Automatic sleep staging plays a vital role in assessing sleep quality and diagnosing sleep disorders. Most existing methods rely heavily on long and continuous EEG recordings, which poses significant challenges for data acquisition in resource-constrained systems, such as wearable or home-based monitoring systems. In this paper, we propose the task of resource-efficient sleep staging, which aims to reduce the amount of signal collected per sleep epoch while maintaining reliable classification performance. To solve this task, we adopt the masking and prompt learning strategy and propose a novel framework called Mask-Aware Sleep Staging (MASS). Specifically, we design a multi-level masking strategy to promote effective feature modeling under partial and irregular observations. To mitigate the loss of contextual information introduced by masking, we further propose a hierarchical prompt learning mechanism that aggregates unmasked data into a global prompt, serving as a semantic anchor for guiding both patch-level and epoch-level feature modeling. MASS is evalutaed on four datasets, demonstrating state-of-the-art performance, especially when the amount of data is very limited. This result highlights its potential for efficient and scalable deployment in real-world low-resource sleep monitoring environments.

Intelligent fault-tolerant (FT) computing has recently demonstrated significant advantages in predicting and diagnosing faults proactively, thereby ensuring reliable service delivery. However, due to the heterogeneity of fault knowledge, dynamic workloads, and limited data support, existing deep learning-based FT algorithms face challenges in fault detection quality and training efficiency. This is primarily because their homogenization of fault knowledge perception difficuties to fully capture diverse and complex fault patterns. To address these challenges, we propose FT-MoE, a sustainable-learning fault-tolerant computing framework based on a dual-path architecture for high-accuracy fault detection and classification. This model employs a mixture-of-experts (MoE) architecture, enabling different parameters to learn distinct fault knowledge. Additionally, we adopt a two-stage learning scheme that combines comprehensive offline training with continual online tuning, allowing the model to adaptively optimize its parameters in response to evolving real-time workloads. To facilitate realistic evaluation, we construct a new fault detection and classification dataset for edge networks, comprising 10,000 intervals with fine-grained resource features, surpassing existing datasets in both scale and granularity. Finally, we conduct extensive experiments on the FT benchmark to verify the effectiveness of FT-MoE. Results demonstrate that our model outperforms state-of-the-art methods.

Jia Liu, Jiaxin Luo, Weiwen Xu, Jonathan M. Garibaldi, Xiao-Kun Wu, Yixue Hao, Min Chen. Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers). 2026.

Human activity prediction is crucial for enabling intelligent smart home services, yet it is often hindered by the scarcity of high-quality, multi-dimensional datasets. Existing datasets are typically fragmented, capturing either long-term activity sequences or short-term device interactions, but rarely both in a unified manner. Traditional data collection methods are costly and time-consuming, while conventional simulation techniques struggle to generate diverse and logically coherent behavior sequences. To address these limitations, we propose SmartLLM, a novel Large Language Model (LLM)-based simulation framework for automated generation of multi-dimensional smart home datasets. SmartLLM simulates simulated agents with distinct profiles (e.g., old man, remote worker, holiday maker) performing daily activities within configurable home environments, generating temporally aligned sequences across Activity-Device-Sensor dimensions. We generate two months of simulated data for three user profiles and validated their plausibility through activity distribution visualization, statistical perplexity analysis, and case studies. Multi-dimensional feature validation experiments further demonstrate that our multi-dimensional data significantly enhances the accuracy of activity prediction models compared to using single-dimensional features. This work successfully addresses key bottlenecks in smart home data acquisition and provides a scalable, high-quality data foundation for advancing smart home algorithm research. The code is available at https://github.com/HuankeZheng/SmartLLM.

The proliferation of hate speech on social media presents an escalating threat to both public discourse and individual mental well-being. Traditional strategies that prioritize detection and removal often neglect to engage directly with hate speakers or address the underlying causes of their hostility. This article proposesHateMediator, a dialogue-based intervention framework that fine-tunes large language models (LLMs) to generate persuasive, context-aware counter-hate speech. The framework emphasizes two core aspects: the generation of effective counter-hate responses and their evaluation through multiturn dialogues. Our fine-tuning approach integrates tutorial-based learning with critical token guidance, enabling LLMs to recognize and reproduce strategic rhetorical patterns observed in expert interventions. To support training and evaluation, we introduce theMedHatedataset, grounded in social science theory, comprising complete dialogue records from 85 real-world hate incidents (including 255 dialogues), expert-crafted counter-responses, and feedback from the original hate speakers. Experimental results show thatHateMediatorconsistently outperforms baseline LLMs across multiple evaluation dimensions. This study advances both the technical frontier of hate speech intervention and the ethical deployment of LLMs in addressing complex social issues.

In a socially tense environment with rising emotional pressure, understanding the spread patterns of group emotions-particularly negative emotions-is crucial for identifying social risks. Extensive research has explored emotion contagion, often using propagation models where node state transitions rely on preset probabilities. However, these methods introduce randomness, making them less reflective of real-world dynamics by failing to capture individual node behaviors and interactions in emotional networks. To address this, our study introduces a novel approach integrating text-based emotion recognition with propagation models, reconstructing emotion contagion at an individual level. This model enhances traditional nodes with multihop agents driven by text emotion analysis, where agents record and respond to neighbors' emotional states. As a result, emotion spread becomes a deterministic process, with individualized infection rates reflecting node variability. We categorized nodes based on emotional states, creating corresponding agent types to form the dynamic agent-based emotion model (AEmo). Tests on real-world and scale-free networks show this method effectively predicts group negative emotion spread and provides insight into individual emotion evolution, validating the model's effectiveness.

Sleep staging is a crucial method for the evaluation of sleep quality and the diagnosis of sleep disorders. In recent years, rapid progress has been made in sleep research through the application of fabric computing and neural networks. Flexible fabric sensors introduced by fabric computing minimize the discomfort of data collection devices on individuals, while neural network-based algorithms can automatically perform sleep staging based on the collected signals. However, there are two key challenges hinder the integration of automatic sleep staging networks with fabric computing: (1) signals in fabric-based environments exhibit strong heterogeneity due to the wide range of individuals, and (2) interactions between individuals and the fabric space introduce behavioral dynamics to the system. In this paper, we propose a masked autoencoder-based sleep staging neural networks (MAESleepNet), designed to integrate automatic sleep staging algorithm with fabric space. Specifically, MAESleepNet addresses the challenge of signal heterogeneity by learning fine-grained representations from local signals. Furthermore, MAESleepNet tackle the challenge of behavioral dynamics through stochastic masking and reconstruction pre-training. Experiments were conducted on three public datasets: (1) Sleep-EDF-20, (2) Sleep-EDF-78 and (3) SHHS. MAESleepNet achieves overall accuracies of 88.9%, 85.5%, and 87.3%, respectively, outperforming other state-of-the-art models. Furthermore, feature visualization and reconstruction visualization experiments were also conducted. The results demonstrates that MAESleepNet is an effective solution to the aforementioned challenges, paving the way for seamless integration into the fabric space.

With the popularity of electric vehicles (EVs), wireless power transmission (WPT) technology has become a hot research topic for next-generation battery charging technology. However, the vulnerability of wireless networks to malicious interference attacks is inherited by WPT. To alleviate the privacy and security issues of WPT, we propose a novel FedDQ, a federated deep reinforcement learning with Q-ensemble, to cope with interference attacks in EV wireless charging network environments. Federated learning protects the security privacy of EVs by training a global model that exploits the property that data and models will not be transmitted. In order to trade-off the training cost and efficiency, we introduce offline-to-online training models by pre-training the offline Q-network with pre-collected data, and the trained model serves as an initialization of the online model. Then, the online Q-network is obtained by weakening or removing the original pessimistic constraints to enhance the training speed. Secondly, we introduce the intelligent reflective surface (IRS) to enhance the security performance of WPT by modifying the IRS phase shift and amplitude to cancel the malicious interference signal. Experimental results show that our proposed FedDQ algorithm has superior performance and outperforms existing baseline methods in terms of anti-jamming metrics.

Transformers are widely utilized in the point cloud domain. However, existing methods tend to overburden Transformer with the dual task of local geometric perception and global feature extraction, limiting its ability to capture highlevel semantic knowledge. To address this issue, we present Representation Decoder (R-Decoder), a novel representation extraction module compatible with various point cloud Transformer methods, enabling the Transformer to focus on its excellent local perception. The R-Decoder iteratively extracts multiple global features from tokens generated by Transformer, refining them to construct an overall representation of point cloud. To ensure full adaptation of the R-Decoder to the knowledge of pre-trained Transformers, we design a cross-modal representation alignment task that leverages multimodal knowledge to specifically pre-train the R-Decoder. As a post-processing module, the R-Decoder seamlessly integrates with Transformers, while decoupling local perception and global representation. This design allows the Transformer to focus on the semantic encoding role for point tokens. Extensive experiments show that our RDecoder significantly boosts the capabilities of 3D representation learning in various point cloud Transformer methods. Notably, it achieves impressive classification accuracies of 95.1% on the ScanObjectNN dataset and 95.3% on the ModelNet40 dataset. Moreover, our method obtains new SOTA on all benchmarks of few-shot and zero-shot classification, while enhancing the multimodal task capabilities of pre-trained Transformers. Code and weights are available athttps://github.com/TangYuan96/RDecoder.

Transformer-based models have recently adopted increasingly complex structure (e.g., deeper or wider stacked network) to promote the representation learning capabilities of vision recognition. However, progressively deeper or wider stacked network cause the expensive computation cost, which hinders their effective deployment in resource-constrained edge clouds or end devices. In this paper, we propose DTSNet, a dynamic transformer slimming model, which scales vision transformers (ViTs) down across layers from both of the model depth and input width. This is the first time to explore the joint reduction of input tokens and model parameters for ViTs under maintaining performance. Specifically, DTSNet adopts a diversity-enhanced weight sharing module to reduce network parameters, where the weight knowledge of multiple adjacent blocks is effectively integrated into one block. Furthermore, DTSNet designs a unified and massively scalable token pruning mechanism that dynamically discarding less important tokens with a model-driven manner, by introducing a series of discriminant parameters, which is a simple change to the common architecture of vision transformers. Extensive experiments are conducted to verify that DTSNet is able to yield high efficacy in compressing parameter space and accelerating model inference. DTSNet-T/-S/-B on ImageNet achieves 3.0M/11.1M/42.9M parameters and 0.8/2.9/13.7 GFLOPs, where number of parameters are reduced by 48%$\sim$51% and inference speed are improved by 1.3$\times \sim 1.5\times$. Experiments results on semantic segmentation and object detection dataset further demonstrate the potential of DTSNet on complex dense prediction tasks. Code will be available upon publication.

Recently, generative aspect-level sentiment quadruple prediction (ASQP) methods based on pre-trained language models have made significant progress. However, some challenges remain in extracting and recognizing complex sentiment elements from semantically rich sentences, limiting the generalization and adaptability of unidirectional generative models in aspect-level sentiment analysis. To overcome this limitation, this article proposes a Generative Aspect-Based Sentiment Quadruple Prediction Model based on Multi-Order Prompting (GenMOP). The model draws on the concept of prompt learning and introduces a multi-order prompting strategy, which breaks the traditional framework of a single generative order and enhances the flexibility and adaptability of the model. Furthermore, we integrate a quadruple quantity-aware module and a multi-view uncertainty-aware module based on a basic generative architecture, not only providing the model with more fine-grained information about the quadruple quantity but also improving the prediction accuracy through uncertainty estimation. The extensive experiments show that the GenMOP method achieves excellent performance in the ASQP task. On the four benchmark datasets including Rest15, Rest16, Rest and Lap, our model achieves F1 score improvements of 1.26%, 0.23%, 0.28%, and 2.07%, respectively, compared to existing state-of-the-arts, demonstrating its effectiveness and superiority in dealing with the joint extraction of multiple sentiment elements of the ASQP model.

The integration of Large Language Models (LLM) with multimodal agentic AI within the Medical Internet of Things (MIoT) ecosystem is redefining modern healthcare intelligence. This convergence enables continuous patient observation, adaptive clinical decision-making, and context-aware interaction between humans and machines across various biomedical data modalities. Healthcare systems generate a wide range of multimodal data, including textual records such as EHRs, prescriptions, and pathology notes; medical imagery such as CT, MRI, fundus, and radiographs; spoken data from consultations and transcriptions; video streams for rehabilitation and physiotherapy monitoring; and sensor readings such as ECG, SpO \({}_{2}\) , and glucose levels. Conventional unimodal algorithms fall short in interpreting this diversity, whereas LLM-augmented agentic frameworks fuse and reason over these heterogeneous sources, grounding their outputs in medical ontologies and coordinating task-specific agents to enhance real-world clinical workflows. This article presents a comprehensive overview of multimodal agentic AI powered by LLM for MIoT-enabled healthcare systems. Introduces a 6D unified taxonomy that covers multimodal input channels, fusion mechanisms, core LLM reasoning capabilities, agentic coordination models, computational deployment layers, and ethical governance frameworks. To contextualize this taxonomy, the discussion includes a Virtual Hospital case study centered on cancer that demonstrates how multimodal signals such as imaging, genomics, patient dialogues, and clinical updates integrate through intelligent agents to enable personalized diagnosis, automated documentation, home rehabilitation, and rapid intervention in emergencies. The survey also consolidates current progress on datasets, benchmarks, and evaluation protocols for AI in multimodal and agentic healthcare. The survey identifies critical research gaps, such as the lack of longitudinal multimodal datasets, standardized evaluation frameworks for multi-agent reasoning, and reliable methods to assess trustworthiness in clinical AI. Furthermore, it examines security and compliance issues such as adversarial manipulation, data leakage, and accountability across distributed agent networks, and it proposes countermeasures through federated data governance, secure MCP-oriented orchestration, and privacy-aware edge deployment strategies. By situating recent advances within the Virtual Hospital paradigm and oncology workflows, this study provides a systematic foundation for developing scalable, secure, and ethically aligned multimodal agentic systems based on LLMs, guiding the next generation of intelligent MIoT-driven healthcare ecosystems.

Intelligent adaptive bitrate (ABR) schemes have been widely recognized for their excellent learning strategies. However, existing intelligent ABR methods have limitations, i.e., the lack of logical reasoning capability for video-aware symbolic representations leads to low sampling efficiency and fails to achieve the optimal performance of Bitrate Adaptation. We introduce NeuroBA, a learning-based approach to realize ABR using neuro-symbolic deep reinforcement learning. NeuroBA trains a neuro-symbolic deep network model without making any assumptions about the edge video scene and without relying on a predefined model. Instead, it enables bitrate decision-making under uncertainty and partial observability by knowledge-driven video quality perception in symbolic first-order logic. To enhance wireless signals, we have introduced Intelligent Reflecting Surface (IRS) technology to address this issue. By dynamically adjusting the phase shift of IRS, the throughput performance of wireless networks is significantly improved. Based on trace-driven and real-world experiments covering a variety of edge video scenarios, and network performance metrics, NeuroBA is compared with state-of-the-art ABR schemes, and NeuroBA exhibits superior performance, with an average QoE improvement of 16.58% (BOLA)-25.34% (Fugu). In particular, it outperforms existing baseline approaches even without pre-programmed models and network scenarios assumed for the edge network.

Video streaming has emerged as a widely used Internet service, in which adaptive bitrate (ABR) algorithms play a critical role in delivering high quality of experience (QoE). However, existing learning-based ABR methods often suffer from limited generalization in unseen and dynamically changing network conditions. Although some meta-reinforcement learning techniques have been proposed to mitigate this issue, they generally depend on additional online training or fine-tuning. To overcome these limitations, this paper introduces EAStream, an environment-aware ABR algorithm based on meta-reinforcement learning for reliable video streaming services. The method employs a variational autoencoder to extract a latent representation of the current network environment from historical interaction data. This latent variable, along with the current system state, is fed into a policy network that perceives network conditions in real time and adapts bitrate decisions accordingly, without requiring further online training. A comprehensive evaluation is conducted using diverse real-world network traces. Experimental results show that EAStream not only achieves leading performance on in-distribution test sets compared to state-of-the-art ABR algorithms, but also demonstrates superior generalization capability on out-of-distribution test scenarios.

With the increasing demand for artificial intelligence generated content (AIGC) services across diverse applications, AIGC service migration is essential to ensuring continuous service for mobile users in edge intelligence networks. However, AIGC service migration can lead to decreased inference accuracy due to the discarding of contextual memory. Furthermore, migrating large-scale AIGC models incurs high migration costs and latency. In this paper, we propose a context-aware AIGC service migration scheme to address the trade-off among inference accuracy, latency, and migration cost. Specifically, we focus on migrating historical AIGC context rather than large-scale AIGC models to achieve cost-efficient service provisioning. To improve service migration performance, we propose a Value of Context (VoC) metric to quantify the relevance and freshness of historical AIGC context. Based on the VoC, we formulate an optimization problem to jointly optimize inference accuracy, latency, and migration cost. To solve this problem, we develop a TransFormer-based Soft actor-critic algorithm for Context-aware AIGC service Migration (TFSCM) that leverages long-term dependencies in historical decisions for optimizing the migration process. Extensive experiments on real-world datasets demonstrate that the proposed TFSCM algorithm significantly enhances system performance compared to baseline solutions.

Enabling Large Language Models (LLMs) to comprehend the 3D physical world remains a significant challenge. Due to the lack of large-scale 3D-text pair datasets, the success of LLMs has yet to be replicated in 3D understanding. In this paper, we rethink this issue and propose a new task: 3D Data-Efficient Point-Language Understanding. The goal is to enable LLMs to achieve robust 3D object understanding with minimal 3D point cloud and text data pairs. To address this task, we introduce GreenPLM, which leverages more text data to compensate for the lack of 3D data. First, inspired by using CLIP to align images and text, we utilize a pre-trained point cloud-text encoder to map the 3D point cloud space to the text space. This mapping leaves us to seamlessly connect the text space with LLMs. Once the point-text-LLM connection is established, we further enhance text-LLM alignment by expanding the intermediate text space, thereby reducing the reliance on 3D point cloud data. Specifically, we generate 6M free-text descriptions of 3D objects, and design a three-stage training strategy to help LLMs better explore the intrinsic connections between different modalities. To achieve efficient modality alignment, we design a zero-parameter cross-attention module for token pooling. Extensive experimental results show that GreenPLM requires only 12% of the 3D training data used by existing state-of-the-art models to achieve superior 3D understanding. Remarkably, GreenPLM also achieves competitive performance using text-only data.

Recent advancements in deep learning have greatly enhanced 3D object recognition, but most models are limited to closed-set scenarios, unable to handle unknown samples in real-world applications. Open-set recognition (OSR) addresses this limitation by enabling models to both classify known classes and identify novel classes. However, current OSR methods rely on global features to differentiate known and unknown classes, treating the entire object uniformly and overlooking the varying semantic importance of its different parts. To address this gap, we propose Salience-Aware Structured Separation (SASep), which includes (i) a tunable semantic decomposition (TSD) module to semantically decompose objects into important and unimportant parts, (ii) a geometric synthesis strategy (GSS) to generate pseudo-unknown objects by combining these unimportant parts, and (iii) a synth-aided margin separation (SMS) module to enhance feature-level separation by expanding the feature distributions between classes. Together, these components improve both geometric and feature representations, enhancing the model’s ability to effectively distinguish known and unknown classes. Experimental results show that SASep achieves superior performance in 3D OSR, outperforming existing state-of-the-art methods. The codes are available at https://github.com/JinfengX/SASep.

Generating 3D meshes from a single image is an important but ill-posed task. Existing methods mainly adopt 2D multiview diffusion models to generate intermediate multiview images, and use the Large Reconstruction Model (LRM) to create the final meshes. However, the multiview images exhibit local inconsistencies, and the meshes often lack fidelity to the input image or look blurry. We propose Fancy123, featuring two enhancement modules and an unprojection operation to address the above three issues, respectively. The appearance enhancement module deforms the 2D multiview images to realign misaligned pixels for better multiview consistency. The fidelity enhancement module deforms the 3D mesh to match the input image. The unprojection of the input image and deformed multiview images onto LRM’s generated mesh ensures high clarity, discarding LRM’s predicted blurry-looking mesh colors. Extensive qualitative and quantitative experiments verify Fancy123’s SoTA performance with significant improvement. Also, the two enhancement modules are plug-and-play and work at inference time, allowing seamless integration into various existing single-image-to-3D methods. Project page: https://github.com/YuQiao0303/Fancy123.

Vehicular edge computing (VEC) is an emerging computing paradigm that is rapidly advancing the development of the Internet of Vehicles (IoV). However, edge server has limited data storage capacity and computing resource, making it difficult to handle the massive offloading requests from IoV applications. Moreover, the mobility of vehicles and dynamic data traffic make it highly challenging to design optimal offloading and resource allocation strategies. To address the challenges mentioned above, we design a cloud-edge–vehicle hierarchical architecture for IoV task offloading, introducing a cloud server to assist in computation and alleviate the overload pressure on edge server. Considering the impact of vehicle mobility on task offloading, we propose a mobility detection method to predict which vehicles might leave the communication range of the base station, thereby preventing task offloading failures. Additionally, to achieve efficient task offloading and resource allocation in this complex IoV system, we propose a multiagent-reinforcement-learning-based vehicle proposal offloading algorithm (MVPOA). This algorithm enables vehicles to autonomously decide whether to process tasks locally or propose offloading to edge server. The edge server then decides whether to accept offloading requests based on task priority and sends rejected tasks to cloud server for processing, thereby maximizing the utilization of resources at each layer of the system. Simulation results demonstrate that MVPOA outperforms other baseline approaches in optimizing system delay and energy consumption.

A multi-tenant metaverse enables multiple users in a common virtual world to interact with each other online. Information sharing will occur when interactions between a user and the environment are multicast to other users by an interactive metaverse (IM) service. However, ineffective information-sharing strategies intensify competitions among users for limited resources in networks, and fail to interpret optimization intent prompts conveyed in high-level natural languages, ultimately diminishing user immersion. In this paper, we explore reliable information sharing in a multi-tenant metaverse with time-varying resource capacities and costs, where IM services are unreliable and alter the volumes of data processed by them, while the service provider dynamically adjusts global intent to minimize multicast delays and costs. To this end, we first formulate the information sharing problem as a Markov decision process and show its NP-hardness. Then, we propose a learning-based system GTP, which combines the proximal policy optimization reinforcement learning with feature extraction networks, including graph attention network and gated recurrent unit, and a Transformer encoder for multi-feature comparison to process a sequence of incoming multicast requests without the knowledge of future arrival information. The GTP operates through three modules: a deployer that allocates primary and backup IM services across the network to minimize a weighted goal of server computation costs and communication distances between users and services, an intent extractor that dynamically infers provider intent conveyed in natural language, and a router that constructs on-demand multicast routing trees adhering to users, the provider, and network constraints. We finally conduct theoretical and empirical analysis on the proposed algorithms for the system. Experimental results show that the proposed algorithms are promising, and superior to their comparison baseline algorithms.

Heterogeneous graph neural networks (HGNNs) have recently demonstrated significant advantages of capturing powerful structural and semantic information in heterogeneous graphs. Different from homogeneous graph neural networks directly aggregating information based on neighbors, HGNNs aggregate information based on complex metapaths. ReRAM-based processing-in-memory (PIM) architecture can reduce data movement and compute matrix-vector multiplication (MVM) in analog. It can be well used to accelerate HGNNs. However, the complex metapath-based aggregation of HGNNs makes it challenging to efficiently utilize the parallelism of ReRAM and vertices data reuse. To this end, we propose ChainPIM, the first ReRAM-based processing-in-memory accelerator for HGNNs featuring high-computing parallelism and vertices data reuse. Specifically, we introduce R-chain, which is based on a chain structure to build related metapath instances together. We can efficiently reuse vertices through R-chain and process different R-chains in parallel. Then, we further design an efficient storage format for storing R-chains, which reduces a lot of repeated vertices storage. Finally, a specialized ReRAM-based architecture is developed to pipeline different types of aggregations in HGNNs, fully exploiting the huge potential of multilevel parallelism in HGNNs. Our experiments show that ChainPIM achieves an average memory space reduction of 47.86% and performance improvement by$128.29\times $compared to NVIDIA Tesla V100 GPU.

Drug combination therapy with significant advantages is a well-established concept in cancer treatment. Some related efforts have been made with multiple artful deep learning techniques. However, they are usually based on data for drug synergy prediction, ignoring the professional characteristics of data and the systematic knowledge accumulation. Meanwhile, integrating the dispersed professional knowledge and effectively utilizing it in data remains a crucial technical challenge. In this study, we propose KSDDC, a novel model for knowledge-aware synergistic discovery of drug combinations from a large language model (LLM) perspective (i.e., from the continuously learnable and refined large database). Within this framework, three main modules are well-designed, i.e., knowledge-aware drug feature auto-encoding, knowledge-aware cell line feature encoding and drug-drug synergy prediction. Informative embeddings of samples are discovered and combined to make accurate drug synergy prediction. Overall, KSDDC is superior compared with the other shallow machine learning based methods and deep learning based methods on several synergistic prediction benchmarks, where about 19% F1-score improvements over the second best method on DrugComb_1 can be observed. Starting with drug synergy prediction, our studies with knowledge-enabled data mining offer valuable insights and serve as a reference method for future research in this field.

The Uniform Resource Locator (URL) is a primary vector for numerous security threats, including phishing, malware propagation, and spam attacks, making URL-based analysis a critical task in security systems. However, existing research often focuses on static lexical features of individual URLs, overlooking deeper semantic, structural, and behavioral signals that can indicate malicious intent or evasive patterns. In this paper, we propose Behavior-Enhanced Semantic URL Embedding, a novel framework that integrates semantic, structural, and contextual information to improve the detection of security threats embedded in URLs. Our model is composed of three core modules: a semantic understanding module to extract token-level and contextual semantics, a topology structure learning module to capture hierarchical and sequential patterns of URL components, and a downstream multi-task adaptation module that fine-tunes embeddings with supervised contrastive learning for various security detection tasks. We evaluate our method across five public datasets covering key security applications such as malicious URL detection, phishing website identification, and spam filtering, consistently achieving superior performance over existing baselines. Additionally, we demonstrate the extensibility of our approach to related security tasks, showcasing its potential integration into real-world threat detection and security monitoring systems.

Clinical staging of liver cancer (CSoLC), an important indicator for evaluating primary liver cancer (PLC), is key in the diagnosis, treatment, and rehabilitation of liver cancer. In China, the current CSoLC adopts the China liver cancer (CNLC) staging, which is usually evaluated by clinicians based on radiology reports. Therefore, inferring clinical information from unstructured radiology reports can provide auxiliary decision support for clinicians. The key to solving the challenging task is to guide the model to pay attention to the staging-related words or sentences, and the following issues may occur: 1) Imbalanced categories: Early- and mid-stage liver cancer symptoms are subtle, resulting in more data in the end-stage. 2) Domain sensitivity of liver cancer data: The liver cancer dataset contains substantial domain knowledge, leading to out-of-vocabulary issues and reduced classification accuracy. 3) Free-text and lengthy report: Radiology reports sparsely describe various lesions using domain-specific terms, making it hard to mine staging-related information. To address these, this article proposes a large language model (LLM)-based Knowledge-aware Attention Network (LKAN) for CSoLC. First, for maintaining semantic consistency, LLM and a rule-based algorithm are integrated to generate more diverse and reasonable data. Second, an unlabeled radiology corpus is pre-trained to introduce domain knowledge for subsequent representation learning. Third, attention is improved by incorporating both global and local features to guide the model's focus on staging-relevant information. Compared with the baseline models, LKAN has achieved the best results with 90.3% Accuracy, 90.0% Macro_F1 score, and 90.0% Macro_Recall.

Patent data generally includes information from different perspectives or different types, and its heterogeneous attributes can be greatly beneficial to data clustering analysis. However, the existing patent analysis method always focus on the patent text cues, and such a strategy merely depends on the feature information to capture the data characteristics, failing to multi-type informative patent representation. Therefore, in this paper, to model the underlying structure/relationships of patent data, we employ the knowledge graph to depict the heterogeneous attributes of patent, and propose a novel Knowledge Graph-based Patent Clustering (KGPC) method, where the relationship reconstruction in knowledge graph as well as clustering-oriented representation refinement for patent clustering are jointly considered. With this model, there are three components, i.e., entity representation refinement, relationship reconstruction and self-supervised entity clustering. Given a patent knowledge graph as input, the entity representation refinement can be mutually boosted by the relationship reconstruction and self-supervised clustering objective, thereby leading to a balanced clustering-oriented output. Extensive experiments on several real-world patent knowledge graph datasets validate the effectiveness of KGPC while compared with the state-of-the-art.

Human digital twin bridges humans with digital avatars in the fabric metaverse, assisting users and healthcare professionals with real-time visualization, analysis, and prediction of personal data sensed by fabric sensors. The human digital twin-assisted healthcare monitoring (HHM) service refreshment refers to sending personal health data to corresponding services hosted on nearby edge servers and receiving the results to update local digital avatars continuously. However, the malicious nature and resource limitations of edge servers may lead to user privacy leaks and refreshment timeout, thereby impacting diagnostics. In this paper, we investigate a novel privacy-enhanced HHM service refreshment maximization problem in the fabric metaverse by considering privacy data encryption, model compression, and personalized user requirements. To this end, we first formulate the above issue as an Integer Linear Programming (ILP) problem, and prove its NP-hardness. Then, a resource scheduler named Wiper is designed, consisting of a shallow-deep distiller and an agile refresher library. To enable efficient inference while preserving user privacy, the former replaces violation modules in existing models with approximations and conducts shallow distillation on model layers to meet operation type and depth limits of homomorphic encryption, and then deep distillation on model parameters to decrease end-to-end refreshment delay. Finally, to satisfy user requirements on accuracy and delay during encrypted refreshments while maximizing the throughput of HHM services in offline and online situations with different problem scales, a series of HHM service refreshment algorithms are merged into the latter, including exact, performance-guaranteed approximation, and residual diffusion reinforcement learning algorithms. Theoretical analyses and experiments demonstrate that our algorithms are promising compared with baseline algorithms.

In real-world physiological and psychological scenarios, there often exists a robust complementary correlation between audio and visual signals. Audio-Visual Event Localization (AVEL) aims to identify segments with Audio-Visual Events (AVEs) that contain both audio and visual tracks in unconstrained videos. Prior studies have predominantly focused on audio-visual cross-modal fusion methods, overlooking the fine-grained exploration of the cross-modal information fusion mechanism. Moreover, due to the inherent heterogeneity of multi-modal data, inevitable new noise is introduced during the audio-visual fusion process. To address these challenges, we propose a novel Cross-modal Contrastive Learning Network (CCLN) for AVEL, comprising a backbone network and a branch network. In the backbone network, drawing inspiration from physiological theories of sensory integration, we elucidate the process of audio-visual information fusion, interaction, and integration from an information-flow perspective. Notably, the Self-constrained Bi-modal Interaction (SBI) module is a bi-modal attention structure integrated with audio-visual fusion information, and through gated processing of the audio-visual correlation matrix, it effectively captures inter-modal correlation. The Foreground Event Enhancement (FEE) module emphasizes the significance of event-level boundaries by elongating the distance between scene events during training through adaptive weights. Furthermore, we introduce weak video-level labels to constrain the cross-modal semantic alignment of audio-visual events and design a weakly supervised cross-modal contrastive learning loss (WCCL Loss) function, which enhances the quality of fusion representation in the dual-branch contrastive learning framework. Extensive experiments conducted on the AVE dataset for both fully supervised and weakly supervised event localization, as well as Cross-Modal Localization (CML) tasks, demonstrate the superior performance of our model compared to state-of-the-art approaches.

Hierarchical federated learning (HFL) improves the scalability and efficiency of traditional federated learning (FL) by incorporating a hierarchical topology into the FL framework. In a typical HFL system, clients are divided into multiple tiers, and the training process involves both local and global model aggregation. However, existing HFL approaches have several significant drawbacks. Firstly, the root parameter server (PS) is vulnerable to single-point failure and also acts as a bottleneck for global aggregation. Additionally, frequent global aggregation over the wide area network (WAN) incurs substantial communication costs, which negatively affect training efficiency. In this paper, we propose a novel HFL algorithm called CPFedAvg to address the aforementioned challenges. CPFedAvg introduces a root-free hierarchical topology, where the top tier consists of multiple PSes, effectively resolving the issues associated with the root PS. Additionally, we substitute the expensive global aggregation with parameter mixing operations between the PSes in the top tier. We analyze the convergence rate of CPFedAvg under non-convex loss. Based on this analysis, we formulate a convex optimization problem to optimize the frequency of executing local aggregations between consecutive parameter mixing operations. To simulate real-world communication networks, we develop FedNetSimulator to simulate a diverse range of FL communication processes. Finally, we conduct extensive experiments using real datasets (i.e., CIFAR-10 and CIFAR-100). The experimental results demonstrate that CPFedAvg can improve model accuracy by up to 18% and the speedup can be as high as 6 compared with the state-of-the-art baselines.

Faithfully reconstructing textured meshes is crucial for many applications. Compared to text or image modalities, leveraging 3D colored point clouds as input (colored-PC-to-mesh) offers inherent advantages in comprehensively and precisely replicating the target object's 360$^{\circ }$∘ characteristics. While most existing colored-PC-to-mesh methods suffer from blurry textures or require hard-to-acquire 3D training data, we propose PointDreamer, a novel framework that harnesses 2D diffusion prior for superior texture quality. Crucially, unlike prior 2D-diffusion-for-3D works driven by text or image inputs, PointDreamer successfully adapts 2D diffusion models to 3D point cloud data by a novel project-inpaint-unproject pipeline. Specifically, it first projects the point cloud into sparse 2D images and then performs diffusion-based inpainting. After that, diverging from most existing 3D reconstruction or generation approaches that predict texture in 3D/UV space thus often yielding blurry texture, PointDreamer achieves high-quality texture by directly unprojecting the inpainted 2D images to the 3D mesh. Furthermore, we identify for the first time a typical kind of unprojection artifact appearing in occlusion borders, which is common in other multiview-image-to-3D pipelines but less-explored. To address this, we propose a novel solution named the Non-Border-First (NBF) unprojection strategy. Extensive qualitative and quantitative experiments on various synthetic and real-scanned datasets demonstrate that PointDreamer, though zero-shot, exhibits SoTA performance (30% improvement on LPIPS score from 0.118 to 0.068), and is robust to noisy, sparse, or even incomplete input data.

Point scene instance mesh reconstruction is a challenging task since it requires both scene-level instance segmentation and instance-level mesh reconstruction from partial observations simultaneously. Previous works either adopt a detection backbone or a segmentation one, and then directly employ a mesh reconstruction network to produce complete meshes from incomplete instance point clouds. To further boost the mesh reconstruction quality with both local details and global smoothness, in this work, we propose JIMR, a joint framework with two cascaded stages for semantic and geometry understanding. In the first stage, we propose to perform both instance segmentation and object detection simultaneously. By making both tasks promote each other, this design facilitates subsequent mesh reconstruction by providing more precisely-segmented instance points and better alignment benefiting from predicted complete bounding boxes. In the second stage, we propose a complete-then-reconstruct procedure, where the completion module explicitly disentangles completion from reconstruction, and enables the usage of pre-trained weights of existing powerful completion and reconstruction networks. Moreover, we propose a comprehensive confidence score to filter proposals considering the quality of instance segmentation, bounding box detection, semantic classification, and mesh reconstruction at the same time. Experiments show that our proposed JIMR outperforms state-of-the-art methods regarding instance reconstruction qualitatively and quantitatively.

Reciprocal recommender systems (RRS) have been widely used in online platforms such as online dating and recruitment. They can simultaneously fulfill the needs of both parties involved in the recommendation process. Due to the inherent nature of the task, interaction data is relatively sparse compared to other recommendation tasks. Existing works mainly address this issue through content-based recommendation methods. However, these methods often implicitly model textual information from a unified perspective, making it challenging to capture the distinct intentions held by each party, which further leads to limited performance and the lack of interpretability. In this paper, we propose a Knowledge-Aware Explainable Reciprocal Recommender System (KAERR), which models metapaths between two parties independently, considering their respective perspectives and requirements. Various metapaths are fused using an attention-based mechanism, where the attention weights unveil dual-perspective preferences and provide recommendation explanations for both parties. Extensive experiments on two real-world datasets from diverse scenarios demonstrate that the proposed model outperforms state-of-the-art baselines, while also delivering compelling reasons for recommendations to both parties.

Automatic multi-modal depression recognition using artificial intelligence technology is crucial to advance early diagnosis and treatment. Existing methods suffer from a weak performance in detecting depression due to incomplete unimodal semantic information and insufficient fusion effects. To address these challenges, we propose a novel Semantic-Enhanced Dual Cross-modal Fusion Network (SE-DCFN) for multi-modal depression recognition, specifically designed for text-audio data. Firstly, we utilize a prompt learning-based text encoder and a language-audio pertaining-based audio encoder to capture specific information to enhance the semantic representation. Then, we introduce a dual cross-modal fusion module based on self-attention and cross-attention mechanisms to effectively explore linguistic and acoustic representation, facilitating inter-modal and intra-modal interaction and fusion. Additionally, a triplet contrastive loss is formulated to optimize the training process of the SE-DCFN. Experimental results on the EATD-Corpus dataset and AVEC-2017 dataset demonstrate the effectiveness and superiority of our proposed SE-DCFN on multi-modal depression recognition, outperforming existing methods.

Existing point cloud semantic segmentation networks cannot identify unknown classes and update their knowledge, due to a closed-set and static perspective of the real world, which would induce the intelligent agent to make bad decisions. To address this problem, we propose a Probability-Driven Framework (PDF)11Code available at: https://github.com/JinfengX/PointCloudPDF. for open world semantic segmentation that includes (i) a lightweight U-decoder branch to identify unknown classes by estimating the uncertainties, (ii) a flexible pseudo-labeling scheme to supply geometry features along with probability distribution features of unknown classes by generating pseudo labels, and (iii) an incremental knowledge distillation strategy to incorporate novel classes into the existing knowledge base gradually. Our framework enables the model to behave like human beings, which could recognize unknown objects and incrementally learn them with the corresponding knowledge. Experimental results on the S3DIS and ScanNetv2 datasets demonstrate that the proposed PDF outperforms other methods by a large margin in both important tasks of open world semantic segmentation.

Yong Cao, Ruixue Ding, Boli Chen, Xianzhi Li, Min Chen, Daniel Hershcovich, Pengjun Xie, Fei Huang. Proceedings of the 18th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers). 2024.

Due to the emergency of multi-view graph data, considerable attention is focused on the multi-view graph clustering. Although great efforts have been made in developing the multi-view graph clustering methods, most of them implicitly follow the homophily assumption, where the connected nodes with edges tend to be in the same category. As a matter of fact, such an ideal assumption is hard to be satisfied in the real-world graph data, and there are some heterogeneous edges connecting dissimilar nodes in graph. How to well consider the homophily and refine the noisy/heterogeneous edges in multi-view graph clustering still remains an under-explored challenge. Therefore, in this paper, we propose a Homophily-enhanced Adaptive Graph Refinement for Multi-view Graph Clustering (HomoMGC) method, where an adaptive graph refinement strategy is seamlessly designed. Specifically, a feature-oriented graph is constructed based on the shared feature, and an integrated graph is computed by averagely fusing all the input adjacent graphs. Then, the feature-oriented graph and integrated graph are stacked into a graph tensor with a low-rank tensor constraint, where a refined affinity probability matrix can be adaptively recovered from the integrated graph by considering multiple graph information as well as the semantics features. Extensive experiments on several benchmark datasets demonstrate the superiority of HomoMGC compared with the state-of-the-art graph clustering methods. For the code reproducibility, the source code of HomoMGC is public available at https://github.com/ManshengChen/Code-for-HomoMGc-master.

In the evolving landscape of sequential recommendation systems, the application of Large Language Models (LLMs) is increasingly prominent. However, current attempts typically utilize general-purpose LLMs, which present a mismatch in capability and a large semantic gap relative to the specialized needs of recommendation tasks. To tackle these issues, we introduce RecCoder, an innovative model that reformulates sequential recommendation as a code completion task. This approach leverages the superior reasoning capability of code LLMs as a backbone, aligning well with the requirements of recommendation systems. To bridge the semantic gap, RecCoder creates extra tokens for each item and employs item content to initialize token embeddings. Furthermore, we have developed a suite of Semantic Adaptation Fine-tuning tasks, tailored to enhance the model's acquisition of both content and collaborative semantic information, thus aligning the model's intrinsic capabilities with the unique demands of recommendation tasks. Through extensive testing on three public datasets, RecCoder has shown remarkable improvements over existing models in terms of recommendation accuracy and efficiency. This success highlights the substantial yet previously underexplored potential of code LLMs in improving recommendation accuracy and efficiency, suggesting a promising new direction for future research in this area. The implementation code is accessible at https://github.com/AllminerLab/Code-for-RecCoder-master.

In next basket recommendation, baskets are usually formed through a large number of user interactions with items in the early stage. In general, the existing methods for next basket recommendation primarily focus on historical purchase behavior of users, assuming that user purchase interests are static, and overlook the dynamic and diverse changes in user purchase interests. In order to fully capture dynamic user interests and provide users with more diverse recommendations, we propose our method, Dynamic Heterogeneous Graph Prompt (DHGP), for next basket recommendation. By constructing a dynamic heterogeneous graph, we can adequately consider the influence of various interactive behaviors on the user's baskets at different times. Furthermore, we introduce a periodic dynamic heterogeneous prompt strategy to capture the interest directions between baskets from different users and provide users with more diverse interest directions. Extensive experimental validation on six real world datasets demonstrates that our method shows strong applicability across datasets under various conditions and outperforms several state-of-the-art recommendation methods. To the best of our knowledge, DHGP is the first next basket recommendation method that effectively combines dynamic and heterogeneous information. The implementation code is accessible at https://github.com/AllminerLab.

With the explosive growth of information, recommendation systems have emerged to alleviate the problem of information overload. In order to improve the performance of recommendation systems, many existing methods introduce Large Language Models to extract textual information from description text. However, Large Language Models are trained on large-scale generic textual data and may face a semantic gap for downstream recommendation tasks. To address the above issues, we propose Contrastive Learning for Adapting Language Model to Sequential Recommendation (CLA-Rec). In CLA-Rec, we first extract text embeddings from description text using Large Language Models and align the text embeddings learned by Large Language Models with the collaborative information through contrastive learning to obtain high-quality item representations. Through semantic alignment, we bridge the semantic gap between Large Language Models and the recommendation task. To map textual information and collaborative information into user representations, we utilize a Transformer model to learn user representations and capture user preferences by combining the semantically aligned item representations. Extensive experiments on three public datasets demonstrate that our method outperforms state-of-the-art approaches on multiple evaluation metrics, illustrating the effectiveness of the CLA-Rec model in adapting Large Language Models to recommendation tasks.

Next-basket recommendation (NBR) infers a set of items that a user will interact with in the next basket. Existing methods often struggle with the data sparsity problem, particularly when the number of baskets is significantly large due to diverse user behaviors. Cross-domain recommendation (CDR) can effectively alleviate this problem in NBR by transferring knowledge across different domains. Nevertheless, these methods often rely on the similarities of overlapping users, which leads to the negative transfer problem and ignores the overlapping items that are general in real-world scenarios like chain stores. In this paper, we provide a clear symbolic definition of cross-store recommendation (CSR) and distinguish it from CDR. We also propose a novel CSNBR model for cross-store next-basket recommendation task. To fully model the transferable collaborative information between two stores, we learn the embeddings of users, baskets, and items by two intra-store bipartite graphs, and use an inter-store unified bipartite graph to transfer the previously learned knowledge. Furthermore, to alleviate the negative transfer problem, we propose to reconstruct the inter-store unified bipartite graph by utilizing user embeddings obtained from the transfer layer and the disentanglement layer. We also employ two sequence encoders to model the historical sequential information at basket-level and item-level. Extensive experiments conducted on real-world datasets demonstrate the effectiveness of the CSNBR model.

In social media platforms such as Weibo, Twitter, and Facebook, a variety of information is diffused daily. Exploring and exploiting the diffusion patterns in this information play crucial roles in areas such as viral marketing, recommendation systems, and public opinion management. However, the diffusion of this information is not merely sequential propagation among users, as most researchers assume. When we observe the diffusion of information in the entire network from a macroscopic perspective, we discover that these phenomena of information diffusion exhibit a series of interconnected relationships, such as alternation or dependency. In traditional methods of information diffusion prediction (IDP), these aspects are often overlooked. To address this, we introduce a substitution theory of information diffusion, minimal substitution (MS), and we combine it with neural networks to design a network model known as MSNN. First, the incorporation of MS theory enables our model to effectively capture the complex interrelations among pieces of information. Second, we analyze the relationship of the multi-scale IDP task, develop a one-step MS-based microscopic IDP method and a dynamic MS-based macroscopic IDP method, and utilize these two methods for joint training to achieve multi-scale prediction. Finally, we validate the accuracy of the proposed MSNN model through training on two real-world datasets with different growth patterns.

Gaze prediction is essential for enhancing user experiences of virtual reality (VR) applications. However, existing methods seldom considered the privacy nature of gaze data, which may reveal both psychological and physiological characteristics of VR users. Moreover, the commonly adopted one-sizefits-all prediction model cannot well capture behavioral patterns of different VR users. In this paper, we propose a privacyaware personalized gaze prediction framework called GazeFed, which can train a personalized gaze prediction model for each user in a collaborative manner. In GazeFed, only intermediate computations are exchanged between users and the server. The raw gaze data samples are locally preserved to protect user privacy. The global model is shared among all users, which can be further trained with local gaze data to generate a personalized prediction model for each individual user. We also propose a deep neural network tailored for VR gaze prediction called GazeNet, which can effectively extract features from VR contents, gaze data and other user behaviors, and improve the accuracy of gaze prediction. Moreover, the technique of differential privacy (DP) is also integrated to provide more privacy protection, and we theoretically prove that GazeFed can well converge and satisfy the requirement of differential privacy in the meanwhile. Last, we conduct extensive experiments to evaluate the effectiveness of our proposed GazeFed on real datasets and various VR scenarios. The experimental results demonstrate that GazeFed outperforms the state-of-the-art approaches.

Large 2D vision-language models (2D-LLMs) have gained significant attention by bridging Large Language Models (LLMs) with images using a simple projector. Inspired by their success, large 3D point cloud-language models (3D-LLMs) also integrate point clouds into LLMs. However, directly aligning point clouds with LLM requires expensive training costs, typically in hundreds of GPU-hours on A100, which hinders the development of 3D-LLMs. In this paper, we introduce MiniGPT-3D, an efficient and powerful 3D-LLM that achieves multiple SOTA results while training for only 27 hours on one RTX 3090. Specifically, we propose to align 3D point clouds with LLMs using 2D priors from 2D-LLMs, which can leverage the similarity between 2D and 3D visual information. We introduce a novel four-stage training strategy for modality alignment in a cascaded way, and a mixture of query experts module to adaptively aggregate features with high efficiency. Moreover, we utilize parameter-efficient fine-tuning methods LoRA and Norm fine-tuning, resulting in only 47.8M learnable parameters, which is up to 260x fewer than existing methods. Extensive experiments show that MiniGPT-3D achieves SOTA on 3D object classification and captioning tasks, with significantly cheaper training costs. Notably, MiniGPT-3D gains an 8.12 increase on GPT-4 evaluation score for the challenging object captioning task compared to ShapeLLM-13B, while the latter costs 160 total GPU-hours on 8 A800. We are the first to explore the efficient 3D-LLM, offering new insights to the community. Code and weights are available at https://github.com/TangYuan96/MiniGPT-3D.

Magnetic resonance imaging (MRI) with the high-resolution in computer-aided diagnostic technology is widely used to provide doctors with diagnostic advice, especially in brain tumor segmentation. In addition, MRI multi-sequence images of brain tumors also provide better image data support for studying brain tumor segmentation. In this paper, an adaptive threshold segmentation numerical optimization spiking neural P system (ATONSNPS or ATONSN P system) is designed to dynamically adjust the threshold quantity. In addition, the ATONSN P system and connectivity algorithm are combined to finish multi-sequence brain tumor segmentation. Experimental results on BraTS2019 show that the multi-sequence brain tumor segmentation approach can achieve more effective segmentation of brain tumor images comparing with several benchmark algorithms.

In recent years, significant breakthroughs have been achieved in smart fabric technology within the healthcare sector, providing an impetus for the smart integration of wearable devices and equipment in medical applications. However, the tight coupling between fabric hardware devices and software solutions, tailored for various scenarios, has led to inefficient utilization of hardware resources and led to challenges for device upgrades and iterations. This paper focuses on the virtualization technology of smart fabric hardware resources and introduces a novel approach, termed “Big Fiber Slicing”. First, we outline the design of novel fiber devices customized for two major application scenarios: health monitoring and protection. Subsequently, we delve into the process of partitioning hardware resources into multiple “fiber slices” to better meet the unique requirements of various application scenarios and services. Next, we built a smart fabric platform, combined with 5 real multi-modal applications with different preferences, to verify the performance of the system when resources are limited and demand changes dynamically. Lastly, we explore the potential challenges that smart fabric technology may encounter in future application scenarios and provide insights into the future direction of this field.

Due to the collective decision-making nature of enterprises, the process of accepting recommendations is predominantly characterized by an analytical synthesis of objective requirements and cost-effectiveness, rather than being rooted in individual interests. This distinguishes enterprise recommendation scenarios from those tailored for individuals or groups formed by similar individuals, rendering traditional recommendation algorithms less applicable in the corporate context. To overcome the challenges, by taking the corporate volunteer as an example, which aims to recommend volunteer activities to enterprises, we propose a novel recommendation model calledAttributeKnowledgeGraphNeuralNetworks (AKGNN). Specifically, a novel comprehensive attribute knowledge graph is constructed for enterprises and volunteer activities, based on which we obtain the feature representation. Then we utilize anextendedVariationalAuto-Encoder (eVAE) model to learn the preferences representation and then we utilize a GNN model to learn the comprehensive representation with representation of the similar nodes. Finally, all the comprehensive representations are input to the prediction layer. Extensive experiments have been conducted on real datasets, confirming the advantages of the AKGNN model. We delineate the challenges faced by recommendation algorithms in Business-to-Business (B2B) platforms and introduces a novel research approach utilizing attribute knowledge graphs.

Most researchers focus on designing accurate crowd counting models with heavy parameters and computations but ignore the resource burden during the model deployment. A real-world scenario demands an efficient counting model with low-latency and high-performance. Knowledge distillation provides an elegant way to transfer knowledge from a complicated teacher model to a compact student model while maintaining accuracy. However, the student model receives the wrong guidance with the supervision of the teacher model due to the inaccurate information understood by the teacher in some cases. In this paper, we propose a dual-knowledge distillation (DKD) framework, which aims to reduce the side effects of the teacher model and transfer hierarchical knowledge to obtain a more efficient counting model. First, the student model is initialized with global information transferred by the teacher model via adaptive perspectives. Then, the self-knowledge distillation forces the student model to learn the knowledge by itself, based on intermediate feature maps and target map. Specifically, the optimal transport distance is utilized to measure the difference of feature maps between the teacher and the student to perform the distribution alignment of the counting area. Extensive experiments are conducted on four challenging datasets, demonstrating the superiority of DKD. When there are only approximately 6% of the parameters and computations from the original models, the student model achieves a faster and more accurate counting performance as the teacher model even surpasses it.

In recent years, the recognition of human emotions based on electrocardiogram (ECG) signals has been considered a novel area of study among researchers. Despite the challenge of extracting latent emotion information from ECG signals, existing methods are able to recognize emotions by calculating the heart rate variability (HRV) features. However, such local features have drawbacks, as they do not provide a comprehensive description of ECG signals, leading to suboptimal recognition performance. For the first time, we propose a new strategy to extract hidden emotional information from the global ECG trajectory for emotion recognition. Specifically, a period of ECG signals is decomposed into sub-signals of different frequency bands through ensemble empirical mode decomposition (EEMD), and a series of multi-sequence trajectory graphs is constructed by orthogonally combining these sub-signals to extract latent emotional information. Additionally, to better utilize these graph features, a network has been designed that includes self-supervised graph representation learning and ensemble learning for classification. This approach surpasses recent notable works, achieving outstanding results, with an accuracy of 95.08% in arousal and 95.90% in valence detection. Additionally, this global feature is compared and discussed in relation to HRV features, with the intention of providing inspiration for subsequent research.

How to localize the rumor source is a common interest of all sectors of the society. Many researchers have tried to use deep-learning-based graph models to detect rumor sources, but they have neglected how to train their deep-learning-based graph models in thenoisysocial network environmentefficiently. Especially for deep learning models, the performance relies on the data scale. However, even though its known that a substantial amount of rumor data distributed across multiple edge servers (e.g., cross-platform), due to conflicting business interests, its challenging to coordinate all parties to train a model driven by many samples while avoiding moving data. Federated learning, is an effective technique to bridge this gap. Therefore, this paper proposes aDistributedRumorSourceDetection viaBoostedFederatedLearning (DRSDBFL). Specifically, this paper proposes an effective rumor source detection method based on a deep-learning-based graph model with a denoising module. To the best of our knowledge, we are the first to attempt to the use of a denoising module to reduce the noisy effects of social networks. Then, we propose a novel boosted federated learning mechanism through boosting the high-quality edge worker to improve the training efficiency. Finally, the effectiveness of the proposed method is verified by extensive experiments.

The 5G networks have extensively promoted the growth of mobile users and novel applications, and with the skyrocketing user requests for a large amount of popular content, the consequent content delivery services (CDSs) have been bringing a heavy load to mobile service providers. As a key mission in intelligent networks management, understanding and predicting the distribution of CDSs benefits many tasks of modern network services such as resource provisioning and proactive content caching for content delivery networks. However, the revolutions in novel ubiquitous network architectures led by ultra-dense networks (UDNs) make the task extremely challenging. Specifically, conventional methods face the challenges of insufficient spatio precision, lacking generalizability, and complex multi-feature dependencies of user requests, making their effectiveness unreliable in CDSs prediction under 5G UDNs. In this article, we propose to adopt a series of encoding and sampling methods to model CDSs of known and unknown areas at a tailored fine-grained level. Moreover, we design a spatio-temporal-social multi-feature extraction framework for CDSs hotspots prediction, in which a novel edge-enhanced graph convolution block is proposed to encode dynamic CDSs networks based on the social relationships and the spatio features. Besides, we introduce the Long-Short Term Memory (LSTM) to further capture the temporal dependency. Extensive performance evaluations with real-world measurement data collected in two mobile content applications demonstrate the effectiveness of our proposed solution, which can improve the prediction area under the curve (AUC) by 40.5% compared to the state-of-the-art proposals at a spatio granularity of 76m, with up to 80% of the unknown areas.

Edge-enabled Vehicular Metaverse (EVM) is a new paradise supported by various compute-intensive Virtual Vehicle Services (VVSs), where users can immerse and enjoy their spiritual world. User immersion is critical during VVS provisioning in the EVM, yet it can be weakened or curtailed by a sense of disengagement caused by unknown failures. Providing redundant backups VVSs (BVVSs) and keeping the Age of Backup Information (AoBI) could effectively resist and avoid this disengagement when failures occur. However, the trajectories of mobile vehicles are unknown and dynamic, which makes it challenging to optimally migrate VVSs and BVVSs or adjust the update frequency of backup information in real-time, so as to ensure service reliability and AoBI while minimizing the cost of accepting VVS-based metaverse services. In this paper, the above long-term issue is first decomposed into discrete single-slot sub-problems that are modeled as integer linear programming problems. Then, a comprehensive resource explorer named spotlighter is designed, where the first and second parts are a metaverse service home prediction algorithm based on deep learning and a VVS migration algorithm based on randomized rounding, respectively. By tracking the dynamical locations of service homes based on current and historical information, the former can help the latter to adaptively minimize migration costs on VVS re-instantiation and traffic transmission among services and moving vehicles. Finally, a cost-adaptive AoBI guarantee algorithm is merged in spotlighter to ensure the freshness of backup status, by trading-off synchronization cost on BVVS migration, backup update, and backup synchronization. Theoretical analyses and experiments based on real databases show that our algorithms are promising compared with baseline algorithms.

Fabric metaverse employs intelligence fibers embedded with flexible sensors to unknowingly gather and transmit massive hypermodal data around humans to a deep neural network-based metaverse inference service (DMS) for continual and real-time analysis. Each DMS has one primary branch and multiple side branches that allow early termination of service with differential accuracy and energy consumption. However, the continual provisioning of compute-intensive DMS with varying requirements for service model, accuracy, delay, and reliability poses a challenge for edge servers characterized by restricted computing resources and intermittent green energy. In this paper, we focus on a continual individualized DMS provisioning problem in the fabric metaverse consisting of a side branch insertion subproblem and a server activation and service deployment subproblem, and formulate them as Integer linear Programming and Markov Decision Process, respectively. Then, we propose a green continual inference (GCI) system, where a pruner with provable approximation ratios trims superfluous branches of every model to the given number$K$to minimize total overflow accuracy between accuracy demands and reserved branches assigned to users. Based on this exit result, each DMS is further divided into several blocks with dependencies to exploit constrained resources of computing and energy in a fine-grained manner. Finally, a learning-based scheduler is merged into GCI to maximize request throughput while minimizing the activation number of edge servers on different demand scenarios, by adaptively activating suitable servers and deploying required blocks and their corresponding backups on selected servers. Theoretical analyses, simulations, and experiments demonstrate that the GCI is promising compared with baseline algorithms.

With the rapid development of edge intelligence cloud (EIC), mobile users are not satisfied with a single artificial intelligence inference service, but require multiple inference services with chain dependencies to process data. Each AI service chain (AISC) is provided as a series of interconnected virtual network functions (VNFs) on-demand deployed on edge servers. However, AISCs experience unpredictable failures and potential attacks in EIC, which may violate different inference requirements of mobile users for reliability, security, and accuracy. How to optimally deploy VNFs and BVNFs on trusted edge servers, and select secure links to form satisfactory AISCs, meanwhile throughput of receiving requests is maximized while deployment cost of computing resources used to create VNFs and BVNFs with different model sizes is minimized in real-time, is a challenging problem. In this paper, the problem is first formulated as an integer linear programming and proved to be NP-hard. Then, we consider the problem under two online backup scenarios: one is an on-site scenario where AISC requests from the mobile devices arrive one by one, and link securities between VNFs and corresponding BVNFs are ignored because they are always on the same edge server; another is an off-site scenario where a set of AISC requests are given, and VNFs and BVNFs are deployed on different servers. Finally, two online algorithms with provable competitive ratios are proposed to solve the above two problems in polynomial time. Theoretical analyses and experiments based on real network topologies demonstrate that our algorithms are promising compared to baseline algorithms.

Content caching in mobile networks is a highly promising technology for reducing traffic load latency and energy consumption levels. Its fundamental goal is to satisfy the supply-and-demand relationships between content providers and content-requesting users. However, previous research primarily focused on the optimization goals of mobile network operators, and although these caching strategies yield improved latency and energy consumption levels, they fall short of satisfying the diverse content demands of users in real-world scenarios. Therefore, this paper proposes a diversity-driven proactive caching strategy that considers multiple stakeholders' requirements, in which the cache hit rate, cache gain for network operators, and content diversity are jointly optimized. Specifically, a novel improved Latent Dirichlet Allocation (LDA) is designed for radio access network caching, which enables diverse topic associations. For user device caching at the network edge, a Gradient-Guided Contrastive Learning (GGCL) is proposed to optimize the multiple objectives of cache systems with limited labeled data resources. Finally, extensive experiments conducted on the MovieLens dataset demonstrate that the proposed method significantly outperforms other methods in various aspects, including content diversity, the cache hit rate, and some network performance metrics, such as the traffic load and cache gain.

Self-supervised learning has achieved great success in both natural language processing and 2D vision, where masked modeling is a quite popular pre-training scheme. However, extending masking to 3D point cloud understanding that combines local and global features poses a new challenge. In our work, we present Point-LGMask, a novel method to embed both local and global contexts with multi-ratio masking, which is quite effective for self-supervised feature learning of point clouds but is unfortunately ignored by existing pre-training works. Specifically, to avoid fitting to a fixed masking ratio, we first propose multi-ratio masking, which prompts the encoder to fully explore representative features thanks to tasks of different difficulties. Next, to encourage the embedding of both local and global features, we formulate a compound loss, which consists of (i) a global representation contrastive loss to encourage the cluster assignments of the masked point clouds to be consistent to that of the completed input, and (ii) a local point cloud prediction loss to encourage accurate prediction of masked points. Equipped with our Point-LGMask, we show that our learned representations transfer well to various downstream tasks, including few-shot classification, shape classification, object part segmentation, as well as real-world scene-based 3D object detection and 3D semantic segmentation. Particularly, our model largely advances existing pre-training methods on the difficult few-shot classification task using the real-captured ScanObjectNN dataset by surpassing over 4% to the second-best method. Also, our Point-LGMask achieves 0.4%$AP_{25}$and 0.8%$AP_{50}$gains on 3D object detection task over the second-best method. 0.4% mAcc and 0.5% mIoU. Codes have been released athttps://github.com/TangYuan96/Point-LGMask.

Immersive service caching, based on the intelligent edge cloud, can meet delay-sensitive service requirements. Although numerous service caching solutions for edge clouds have been designed, they have not been well explored. Moreover, to the best of our knowledge, there is no work to consider the immersive service caching scheme under the supply of renewable energy. In this article, we investigate the service caching problem under the renewable energy supply to minimize service latency while making full use of renewable energy. Specifically, we formulate the service caching and renewable energy harvesting problem, which considers the dynamic renewable energy, unknown service requests, and limited capacity of the edge cloud. To solve this problem, we propose an effective algorithm, called OSCRE. Our algorithm first uses Lyapunov optimization to convert the time-average problem into time-independence optimization and thus realizes optimal renewable energy harvesting. Then, it realizes the service caching scheme using data-driven combinatorial multi-armed bandit learning. The simulation results show that the OSCRE scheme can save service latency while making sufficient use of renewable energy.

Recently, the advancements in edge computing have boosted the deployment of video analysis systems based on deep learning, which breaks the limitation of the constrained communication and computing resources of local devices. However, processing multi-scene high-resolution video streams in crowd surveillance remains a significant challenge since it is difficult to formulate dynamic video content and communication environments to support offloading decisions. To bridge the gap between applications and modeling, this paper presents aReal-TimeCloud-edge-deviceCollaboration framework, which enables fast and accurateCrowd counting (RT3C) on the real dataset. RT3C comprises key frame detection, adaptive patch partition, patch encoder and decoder and computation offloading decision, designed to divide key frames into a minimum number of patches and determine the offloading location of patches. A Real-Time Multi-Agent Actor-Critic (RTMAAC) algorithm based on multi-agent reinforcement learning is proposed to decide whether to compute patches with a lightweight model on edge or a large model on cloud. Unlike traditional approaches ignoring the contents, RTMAAC is a dynamic online decision algorithm based on context of the network and video. Extensive experiments demonstrate that RT3C effectively discriminate the valid frames and optimizes offloading decisions in complex environments, outperforming other baseline algorithms on the two crowd counting datasets. In summary, RT3C provides a promising framework for multi-scene video streams, which can be extended to other applications to realize video computation based on deep models.

The advance of Digital Twin (DT) technology sheds light on seamless cyber-physical integration with the Industry 4.0 initiative. Through continuous synchronization with their physical objects, DTs can power inference service models for analysis, emulation, optimization, and prediction on physical objects. With the proliferation of DTs, Digital Twin Network (DTN) slicing is emerging as a new paradigm of service providers for differential quality of service provisioning, where each DTN is a virtual network that consists of a set of inference service models with source data from a group of DTs, and the inference service models provide users with differential quality of services. Mobile Edge Computing (MEC) as a new computing paradigm shifts the computing power towards the edge of core networks, which is appropriate for delay-sensitive inference services. In this paper we consider Age of Information (AoI)-aware inference service provisioning in an MEC network through DTN slicing requests, where the accuracy of inference services provided by each DTN slice is determined by the Expected Age of Information (EAoI) of its inference model. Specifically, we first introduce a novel AoI-aware inference service framework of DTN slicing requests. We then formulate the expected cost minimization problem by jointly placing DT and inference service model instances, and develop efficient algorithms for the problem, based on the proposed framework. We also consider dynamic DTN slicing request admissions where requests arrive one by one without the knowledge of future arrivals, for which we devise an online algorithm with a provable competitive ratio for dynamic request admissions, assuming that DTs of all objects have been placed already. Finally, we evaluate the performance of the proposed algorithms through simulations. Simulation results demonstrate that the proposed algorithms are promising, and the proposed online algorithm improves the number of admitted requests by more than 6% than its counterpart.

Semantic scene completion (SSC) aims to complete a partial 3D scene and predict its semantics simultaneously. Most existing works adopt the voxel representations, thus suffering from the growth of memory and computation cost as the voxel resolution increases. Though a few works attempt to solve SSC from the perspective of 3D point clouds, they have not fully exploited the correlation and complementarity between the two tasks of scene completion and semantic segmentation. In our work, we present CasFusionNet, a novel cascaded network for point cloud semantic scene completion by dense feature fusion. Specifically, we design (i) a global completion module (GCM) to produce an upsampled and completed but coarse point set, (ii) a semantic segmentation module (SSM) to predict the per-point semantic labels of the completed points generated by GCM, and (iii) a local refinement module (LRM) to further refine the coarse completed points and the associated labels from a local perspective. We organize the above three modules via dense feature fusion in each level, and cascade a total of four levels, where we also employ feature fusion between each level for sufficient information usage. Both quantitative and qualitative results on our compiled two point-based datasets validate the effectiveness and superiority of our CasFusionNet compared to state-of-the-art methods in terms of both scene completion and semantic segmentation. The codes and datasets are available at: https://github.com/JinfengX/CasFusionNet.

Depression is a mental disorder caused by factors such as genetics, life events and social influences, and has become a major public health problem worldwide. Previous studies have demonstrated the potential of functional near-infrared spectroscopy (fNIRS) in the diagnosis of depression. However, in the real medical scene, fNIRS data are difficult to obtain, limited in number and suffer from class imbalance. To overcome these problems, in this paper, we propose a novel model for depression identification based on data augmentation and pseudo-sequence of fNIRS. Specifically, the data augmentation using the time masking and warping method generates richer data. Then, a stimulation task-driven data pseudo-sequence method is designed to map the sequence data into pseudo-sequence activation images. Finally, a depression recognition model is established based on the class imbalance loss function. Experiments show that the precision of our depression recognition model reaches 0.94. This scheme transforms fNIRS data into image sequences, which provides a new solution idea for subsequent research.

Audio and vision are important senses for high-level cognition, and their special strong correlation makes audio-visual coding a crucial factor in many multimodal tasks. However, there are two challenges in audio-visual coding. First, the heterogeneity of multimodal data often leads to misalignment of cross-modal features under the same sample, which reduces their representation quality. Second, most self-supervised learning frameworks are constructed based on instance semantics, and the generated pseudo labels introduce additional classification noise. To address these challenges, we propose a Supervised Cross-modal Contrastive Learning Framework for Audio-Visual Coding (SCLAV). Our framework includes an audio-visual coding network composed of an inter-modal attention interaction module and an intra-modal self-integration module, which leverage multimodal complementary and hidden information for better representation. Additionally, we introduce a supervised cross-modal contrastive loss to minimize the distance between audio and vision features of the same instance, and use weak labels of multimodal data to eliminate the feature-oriented classification noise. Extensive experiments on the AVE and XD-Violence datasets demonstrate that SCLAV outperforms the state-of-the-art results, even with limited computational resources.

The emergence of mobile edge computing (MEC) technology has deployed edge clouds with strong computing capabilities closer to Internet of Thing (IoT) devices, which can effectively meet the demands for computing power and latency. However, in addition to the stringent latency requirements, more and more emerging IoT applications also have higher standards for the freshness and timeliness of collected information. In order to ensure the freshness and high-information value in IoT system, we propose an Age of Information (AoI)-based optimization strategy for computation offloading and transmission scheduling. The strategy considers the AoI during the transmission phase and the execution phase, respectively, under the constraints of delay and remaining energy. Then, a joint optimization model is established based on the comprehensive benefits of AoI and computation rate. To address the strong coupling between the offloading decision and the transmission decision, the original optimization problem is divided into two stages. By the use of the deep deterministic policy gradient (DDPG) algorithm and the dueling double deep$Q$network (D3QN) algorithm, the solution is obtained in terms of the offloading decision and transmission scheduling decision, respectively. The proposed joint optimization strategy considers the impact of the transmission decision on the offloading decision and is adaptable to the dynamic changes in the channel connection between the edge cloud and the user due to user mobility. Experimental results show that compared with other offloading and transmission strategies, the proposed approach has higher overall system revenue and lower AoI.

Sensing and computing based on intelligent fabrics can meet the ultra-reliable and low-latency communication (URLLC) needs of sixth-generation wireless (6G) by integrating sensing units into fabric fibers to perceive user data. Although some researchers have designed sensing or computing solutions, such solutions have not been well explored. In this paper, we consider the joint sensing adaptation and model placement in a 6G fabric space. We first propose an intelligent-fiber-driven 6G fabric computing network to minimize acquisition latency while ensuring accuracy. Then, we formulate an optimization model that takes the fabric sampling rate, sampling density, and model placement as variables. To solve the model, we propose an effective learning algorithm based on deep reinforcement learning. That is, by transforming the optimization problem into a state space, action space, and reward function, we design an optimal sensing and placement scheme. The simulation results show that our proposed scheme can achieve optimal sensing and computing compared with several baseline algorithms.

Digital twin (DT)-assisted mobile edge network can achieve energy-efficient task offloading by optimizing the decision-making in real time. Although many DT-assisted task offloading solutions in mobile edge networks have been designed, stochastic asynchronizations between the DTs and physical entities are still ignored. In this paper, we investigate a task offloading problem in a DT-assisted URLLC-enabled mobile edge network which considered the uncertain deviation between DT estimated values and physical actual values. Specifically, we formulate a latency and energy consumption minimization problem by optimizing task offloading, resource allocation, and power management. To solve this problem, we propose a DT-assisted robust task offloading scheme (DTRTO) based on learning composed of decision and deviation networks. The deviation network predicts the worst-case deviations based on the pre-decision, and the decision network optimize the decision considered the worst-case deviation. The simulation results show that, compared to the baseline algorithms, the DTRTO scheme can realize low latency and energy consumption in task offloading while maintaining high robustness.

Drone-swarm-assisted mobile edge computing (MEC) provides extra computation and storage capacity for smart city applications and the Industrial Internet of Things. To solve the problems of traditional fixed base stations in a complex terrain, including cost of deployment, transmission loss of telecommunication, and limited coverage, this article brings forward the unmanned aerial vehicles (UAVs) as MEC nodes in the air. For the purpose of matching the dynamic mobile devices and UAV trajectory, this article raises a multi-UAVs-assisted MEC offloading algorithm based on global and local path planning controlled by ground station and onboard computer. Firstly, this article considers a drone swarm scheduling and allocation strategy based on the priority of monitoring areas, UAVs residual energy and distance to target points, so as to minimize the global flight length and energy consumption. Secondly, based on user mobility, this article calculates the optimal communication coverage of a UAV, and jointly optimizes the local path planning and computing offloading, so as to maximize the number of offloading services and minimize the total latency in completing the computation task. Finally, based on the total latency and energy consumption of path planning and computation offloading, a UAV cluster computation offloading strategy with optimized energy efficiency is realized. Experimental results prove that the proposed algorithm can provide more offloading services while obtaining shorter path length and greater energy efficiency.

With the large-scale commercialization of 5G, the global industry has started the exploration of the next generation mobile communication technology (6G). From mobile Internet, to IoT, and then to the smart connection of everything, 6G will transform from 5G’s service objects of people and things to the intelligent networking of agent that supports human–machine–object. 6G networks should have the characteristics of ubiquitous intelligence and ubiquitous perception, which poses challenges for 6G network construction. Therefore, we propose a 6G Semantic Communication Scheme based on Intelligent Fabrics for transportation in-cabin scenarios (6GSCS-IF), which can provide senseless intelligent interaction in transportation in-cabin environment through widely and flexibly deployed intelligent fabrics, demonstrating the superiority of intelligent fabrics in realizing human–machine–object intelligent sensory interaction. Then, we propose a Deep Learning-based Semantic Communication Model for Time-series data (DL-SCMT), and use deep learning for semantic sensing and information extraction to build an end-to-end semantic communication system. The experimental results show that the semantic communication services provided by this model can achieve better signal reconstruction and higher-order intelligent services compared with traditional communication methods.

Due to the expensive and laborious annotations of labeled data required by fully-supervised learning in the crowd counting task, it is desirable to explore a method to reduce the labeling burden. There exists a large number of unlabeled images in the wild that can be easily obtained compared to labeled datasets. Based on the characteristics of consistent spatial transformation with the annotations of heads and image, this paper proposes a self-supervised learning framework with unlabeled and limited labeled data for pre-training and fine-tuning crowd counting model (SSL-FT). It includes an online network and a target network that receive the same images but are randomly processed by two defined augmentation transformations. We leverage unlabeled data to pre-train the online network based on a self-supervised loss and small-scale labeled data to transfer the model to a specific domain based on a fully-supervised loss. We demonstrate the effectiveness of the SSL-FT on four public datasets including ShanghaiTech PartA, PartB, UCF-QNRF and WorldExpo'10 utilizing a classical counting model. Experimental results show that our approach performs better than state-of-art semi-supervised methods.

Cell-to-cell communication (CCC) plays essential roles in multicellular organisms. the identification of CCC between cancer cells themselves and one between cancer cells and normal cells in tumor microenvironment contributes to the understanding of carcinogenesis, cancer development and metastasis. CCC is usually mediated by Ligand-Receptor Interactions (LRIs). In this manuscript, we developed an LRI-mediated CCC estimation framework (LRI-EnABCLG) by incorporating LRI collection, prediction and filtering, CCC inference and visualization. First, four LRI datasets were collected. Second, LRIs were predicted by a heterogeneous deep ensemble model. Third, LRIs were filtered by combining single-cell sequencing (scRNA-seq) data. Fourth, CCC was inferred by combining the filtered LRIs and scRNA-seq data. Finally, the proposed CCC prediction framework was applied to CCC analysis in colorectal tumor tissues. Our proposed LRI-EnABCLG model obtained better LRI prediction performance. Case study demonstrated that fibroblasts was more likely to communicate with colorectal cancer cells, which was in accord with the results from iTALK (a classical CCC analysis pipeline). We anticipate that this work can contribute to diagnosis and treatment of cancers.

The future ubiquitous network, which is mainly characterized by full coverage communication, air-ground integration, multidimensional fusion, network reconfiguration and sensing-communication-computing integration, has become the development trend of 6G technology. The realization of ubiquitous coverage and perceptive fusion of IoT-UAV-Edge is an urgent problem to be solved for complex fusion services. Therefore, this paper proposes a drone-enabled smart air agent in 6G edge fusion system. Firstly, the energy efficient dynamic routing strategy based on joint air-ground control optimization is designed to improve the fusion sensing performance and prolong the service time of drone swarm. Then, the system integration of user-IoT-UAV-Edge is realized to achieve the functionalities of perception, transmission, computing and analysis. Finally, an airborne data fusion mechanism based on multi-source sensing is designed to solve the associated cognitive optimization problem for multi-modal information. The experimental results invalidate the effectiveness and practicability of our system on autonomous path planning, effective computing offloading and accurate airborne fusion.

As the mainstream solution for semi-supervised learning (SSL), pseudo-labeling-based approaches have achieved re-markable success. However, an obvious drawback of existing methods is that the valuable semantic relationships among categories are often ignored, thus leading to suboptimal encoded embeddings. To address this, we present a novel Semantics-Enhanced Pseudo Labeling Network, called SEPL-Net, for image analysis in a semi-supervised manner. SEPL-Net explores the prior knowledge of visual similarity between different classes to improve the quality of pseudo label decision making. Particularly, we encode semantic labels combined with the one-hot label to jointly train our network by exploiting their disagreement. To alleviate the difficulty of labeling unlabeled images due to the introduction of semantic labels, we further design different classifiers with differentiated strong augmentation modes to enable cooperative pseudo labeling. Extensive experimental results show that our SEPL-Net outperforms existing SSL methods with the averaged 1.84% accuracy improvement on image classification task. Code is available at https://github.com/sweetvicky/SEPLNet.git.

Mobile edge computing (MEC) is a key technology that enables the deployment of applications (or services) at the proximity of mobile users. However, the performance of mobile edge computing is sensitive to the quality and availability of underlying connection links. It is still unclear to what extent intermittent connectivity affects the performance of mobile edge computing. In this paper, we make the first attempt to quantify the influence of intermittent connectivity on mobile edge computing from a theoretical perspective. Specifically, we propose an analytical framework based on discrete-time Markov chain and derive a closed-form expression of the task processing time under different network conditions. Our model can be further extended to account for the case with group task arrivals. We also conduct extensive simulations to examine the accuracy of our proposed analytical models with both synthetic and real-world user mobility traces. The results show that our model can well capture the influence of intermittent connectivity on MEC. Our model sheds important insights into the impact of intermittent connectivity on task processing in MEC, which we believe should be taken into account when designing future MEC systems.

With the widespread application of artificial intelligence and the Internet of Things, the intellectualization of the industrial Internet of Things (IIoT) has received more and more attention. However, in the application scenario with numerous sensors, the contradiction between massive requests of computing tasks and high requirements of inference quality affects the operation efficiency and service reliability. Moreover, due to the heterogeneity of computing resources and the randomness of communication environments of the cloud-edge system, how to compute and deploy deep learning models in a cloud-edge collaborative environment has also become a challenging problem. Therefore, this article presents a collaborative cloud-edge service cognitive framework for deep neural network (DNN) model service configuration to provide dynamic and flexible computing services. In order to adapt to different service requirements, we explored the tradeoffs between accuracy, latency, and energy consumption indicators, and a revenue target is established, which considers the quality of service experience and the system energy consumption to improve resource utilization efficiency. By transforming the optimization of the revenue target into a partially observable DNN configuration reinforcement learning problem, a dueling deep Q-learning network-based self-adaptive DNN configuration algorithm is proposed. Experimental results show that the proposed mechanism can effectively learn from external experience, adapt to the dynamic network environment, and reduce delay and energy consumption while meeting the service requirements.

The papers in this special section focus on the use of artificial intelligence (AI)-enabled technologies to address human wellness. As the COVID-19 pandemic took hold over the last several years, there was an urgent demand to pay more attention to psychological health for human wellness by providing methods and means of sensing psychological parameters, emotional care and mental disorder patient monitoring, especially during these difficult times. With the aid of wearable computing technology and artificial intelligence, emotion and mental disorder detections are available through sensing and analyzing psychological parameters. Discusses the use of AI-based patient monitoring and the ability to monitor human wellness via remote sensing technologies. The papers in this issue provide a snapshot of some of the latest research advances on the research and application of Small Things and Big Data, knowledge discovery and knowledge representation for the combination towards biomedical and health informatics.

In recent years, depression has become an increasingly serious problem globally. Previous studies of automatic depression recognition based on functional near-Infrared spectroscopy (fNIRS) or other brain imaging techniques have shown potential to serve as auxiliary diagnosis methods that provide assistance to medical professionals. Recently, some studies have found that, besides directly using the data themselves (temporal data), the use of functional connectivity among channels (spatial data) also can be effective. In this paper, we propose a method based on Graph Neural Network (GNN) that combines both temporal and spatial features of fNIRS data for automatic depression recognition. Specifically, fNIRS data of 96 subjects were collected and pre-processed. Basic statistical metrics of each channel were extracted as temporal features, and channel connectivity (coherence and correlation) were calculated as spatial features. Point-biserial analysis was conducted on these features and depression labels as a data-driven motivation. For classification, we considered data of each subject as a graph, with temporal features as node features and spatial features as edge weights. The graphs were fed into GNNs for training and testing. Experimental results showed that our GNN-based methods realized the best depression recognition performance compared with classical machine-learning methods regarding accuracy, F1 score, and precision, especially in F1 score for over 10%.

The significant achievements have been made in crowd detection and tracking due to the advancement of artificial intelligence in the autonomous driving. However, the image-based methods have strict requirements for the collection conditions of video, and the development of the new generation of flexible fabrics has become potential sensors to perceive context. In this paper, an intelligent fabric space enabled by multi-sensing sensors is established to track the motion objects. We propose a behavior analysis pipeline including the modules of data preparation, trajectory coupling, motion scenario segmentation, and motion pattern measurement to capture the crowd information from micro-level and macro-level over the intelligent fabric space. After making preprocess for the multi-sensing data, a coupling mechanism is formulated to fuse the video-based trajectory and fabric-based trajectory. And an automatic motion scenario segmentation model divides the surrounding scenario into main-crowd, sub-crowd, and background according to the motion behavior. Further, we define measurement metrics to analyze the motion pattern for the different crowds. Extensive experiments prove that our proposed methods effectively fuse multiple trajectories and realize the crowd segmentation and the motion description. This will greatly help autonomous vehicles and control system perceive the surrounding pedestrians and the environment to make precise driving decisions.

The outbreak of the corona virus disease 2019 (COVID-19) has caused serious harm to people’s physical and mental health. Due to the serious situation of the epidemic, a lot of negative energy information increases people’s psychological burden. However, effective interventions against mental health problems are not in abundance. To address such challenges, in this article, we propose the concept of negative information to describe information that has a negative impact on people’s mental health. To achieve the measurement of negative information, the level of mental health inversely measures the degree of negative information. Specifically, we design a system to measure the negative information used to monitor the mental health state of the user under the impact of negative information. The cognition of mental health is realized based on the intelligent algorithm deployed on the edge cloud, and the needs of users can be responded to in real time in practical applications. Finally, we use real collected dataset to verify the influence of negative information. The experiments show that the system can achieve negative information measurement and provide an effective countermeasure for solving mental health problems during a pandemic situation.

With the rapid economic development, the prominent social competition has led to increasing psychological pressure of people felt from each aspect of life. Driven by the Internet of Things and artificial intelligence, intelligent psychological pressure detection systems based on deep learning and wearable devices have acquired some good results in practical application. However, existing studies argue that the psychological stress state is influenced by the current environment. They put much attention on the momentary features but ignore the dynamic change process of mental status in the time dimension. Besides, the lack of research in the general laws of psychological stress makes it difficult to quantitatively evaluate the stress status, resulting in the inability to perceive the stress state of users effectively. Thus, this article proposes an evaluation mechanism of psychological stress for adjusting the mental status of users. Specifically, we design a multi-dimensional feature space and a time-aware feature encoder, which integrate various stress features and capture time characteristics of stress state change. Moreover, a novel mental state model is proposed, which uses the pressure features with time characteristics to evaluate the pressure stress level. This model also quantifies the internal relationship between pressure features. Last, we establish a practicable testbed to demonstrate how to evaluate and adjust mental state of users by the proposed evaluation mechanism of psychological stress.

With the growth of participating clients, the centralized parameter server (PS) will seriously limit the scale and efficiency of Federated Learning (FL). A straightforward approach to scale up the FL system is to construct a Parallel FL (PFL) system with multiple parallel PSes. However, it is unclear whether PFL can really accelerate FL or reduce the training time of FL. Even if the answer is yes, it is non-trivial to design a highly efficient parameter average algorithm for a PFL system. In this paper, we propose a completely parallelizable FL algorithm called P-FedAvg under the PFL architecture. P-FedAvg extends the well-known FedAvg algorithm by allowing multiple PSes to cooperate and train a learning model together. In P-FedAvg, each PS is only responsible for a fraction of total clients, but PSes can mix model parameters in a dedicatedly designed way so that the FL model can well converge. Different from heuristic-based algorithms, P-FedAvg is with theoretical guarantees. To be rigorous, we theoretically analyze the convergence rate of P-FedAvg in terms of the number of conducted iterations, the communication cost of each global iteration and the optimal weights for each PS to mix parameters with its neighbors. Based on theoretical analysis, we conduct a case study on five typical overlay topolgoies formed by PSes to further examine the communication efficiency under different topologies, and investigate how the overlay topology affects the convergence rate, communication cost and robustness of a PFL system. Lastly, we perform extensive experiments with real datasets to verify our analysis and demonstrate that P-FedAvg can significantly speed up FL than traditional FedAvg and other competitive baselines. We believe that our work can help to lay a theoretical foundation for building more efficient PFL systems.

Federated learning (FL) emerges as a promising paradigm to enable a federation of clients to train a machine learning model in a privacy-preserving manner. Most existing works assumed that the central parameter server (PS) determines the participation of clients implying that clients cannot make autonomous participation decisions. The above assumption is unrealistic because the participation in FL training may incur various cost and clients also have strong desire to be rewarded for participation. To address this problem, we design a novel autonomous client participation scheme to incentivize clients. Specifically, the PS provides a certain reward shared among participating clients for each training round. Clients decide whether to participate each FL training round or not based on their own utilities (i.e., reward minus cost). The process can be modeled as a minority game (MG) with incomplete information and clients end up in the minority side win after each training round because the reward of each participating client may not cover its cost if too many clients participate and vice verse. The challenge of autonomous participation schemes lies in lowering thevolatilityof participating clients in each round due to the lack of coordination among clients. Through solid analysis, we prove that: 1) The volatility of participating clients in each round is very high under the standard MG scheme. 2) The volatility of participating clients can be reduced significantly under the stochastic MG scheme. 3) A coalition based MG is proposed, which can further reduce the volatility in each round. By conducting extensive experiments in real settings, we demonstrate that the stochastic MG-based scheme outperforms other state-of-the-art algorithms in terms of utility and volatility, and the coalition MG-based client participation scheme can further boost the utility by 39%-48% and reduce the volatility by 51%–100%. Moreover, our algorithms can achieve almost the same model accuracy as that obtained by centralized client participation algorithms.

It is always a challenging problem to deliver a huge volume of videos over the Internet. To meet the high bandwidth and stringent playback demand, one feasible solution is to cache video contents on edge servers based on predicted video popularity. Traditional caching algorithms (e.g., LRU, LFU) are too simple to capture the dynamics of video popularity, especially long-tailed videos. Recent learning-driven caching algorithms (e.g., DeepCache) show promising performance, however, such black-box approaches are lack of explainability and interpretability. Moreover, the parameter tuning requires a large number of historical records, which are difficult to obtain for videos with low popularity. In this paper, we optimize video caching at the edge using a white-box approach, which is highly efficient and also completely explainable. To accurately capture the evolution of video popularity, we develop a mathematical model calledHRSmodel, which is the combination of multiple point processes, including Hawkes’ self-exciting, reactive and self-correcting processes. The key advantage of the HRS model is its explainability, and much less number of model parameters. In addition, all its model parameters can be learned automatically through maximizing the Log-likelihood function constructed by past video request events. Next, we further design an online HRS-based video caching algorithm. To verify its effectiveness, we conduct a series of experiments using real video traces collected from Tencent Video, one of the largest online video providers in China. Experiment results demonstrate that our proposed algorithm outperforms the state-of-the-art algorithms, with 15.5% improvement on average in terms of cache hit rate under realistic settings.

In today's Internet, recommender systems play an indispensable role in helping users discover items of interests, such as products, books, movies and so on. However, a higher recommendation accuracy is commonly at the cost of more disclosure of user privacy. Thus, a wider adoption of recommender systems poses significant security and privacy concerns to users. In this article, we propose a light-weight privacy-preserving framework calledRAPfor recommender systems, which can protect user privacy while still ensuring a high recommendation accuracy. Instead of directly sending users’ private ratings to the recommender, users first conduct a local perturbation operation on private ratings, and then send the perturbed ratings to the recommender. The recommender can run recommendation algorithms directly over the perturbed ratings and return the results to users. Different from crypto-based methods, our perturbation and de-perturbation methods are linear operations. Thus,RAPis light-weight and highly efficient in privacy protection. To be more rigorous, we formally prove that the order of recommendation accuracy will not decrease when ourRAPframework is applied to any MF (Matrix Factorization)-based recommender systems. We also derive the closed-form expression for the degree of privacy preservation of our framework. Finally, we conduct extensive evaluations using large-scale real-world datasets to verify the effectiveness of ourRAPframework and compare with other baseline algorithms. The results show that ourRAPframework can improve the degree of privacy preservation from zero to over 0.5 for theMovielensdataset and 4 for theJesterdataset, and still maintain the approaching level of recommendation accuracy.

Limited by the computational capabilities and battery energy of terminal devices and network bandwidth, emotion recognition tasks fail to achieve good interactive experience for users. The intolerable latency for users also seriously restricts the popularization of emotion recognition applications in the edge environments such as fatigue detection in auto-driving. The development of edge computing provides a more sustainable solution for this problem. Based on edge computing, this article proposes a multi-modal multi-layer emotion-aware service (MULTI-EASE) architecture that considers user’s facial expression and voice as a multi-modal data source of emotion recognition, and employs the intelligent terminal, edge server and cloud as multi-layer execution environment. By analyzing the average delay of each task and the average energy consumption at the mobile device, we formulate a delay-constrained energy minimization problem and perform a task scheduling policy between multiple layers to reduce the end-to-end delay and energy consumption by using an edge-based approach, further to improve the users’ emotion interactive experience and achieve energy saving in edge computing. Finally, a prototype system is also implemented to validate the architecture of MULTI-EASE, the experimental results show that MULTI-EASE is a sustainable and efficient platform for emotion analysis applications, and also provide a valuable reference for dynamic task scheduling under MULTI-EASE architecture.

The arrival of 5G networks has extensively promoted the growth of content delivery services (CDSs). Understanding and predicting the spatio-temporal distribution of CDSs are beneficial to mobile users, Internet Content Providers and carriers. Conventional methods for predicting the spatio-temporal distribution of CDSs are mostly base-stations (BSs) centric, leading to weak generalization and spatio coarse-grained. To improve the spatio accuracy and generalization of modeling, we propose user-centric methods for CDSs spatio-temporal analysis. With geocoding and spatio-temporal graphs modeling algorithms, CDSs records collected from mobile devices are modeled as dynamic graphs with spatio-temporal attributes. Moreover, we propose a spatio-temporal-social multi-feature extraction framework for spatio fine-grained CDSs hot spots prediction. Specifically, an edge-enhanced graph convolutional block is designed to encode CDSs information based on the social relations and the spatio dependence features. Besides, we introduce the Long Short Term Memory (LSTM) to further capture the temporal dependence. Experiments on two real-world CDSs datasets verified the effectiveness of the proposed framework, and ablation studies are taken to evaluate the importance of each feature.

Unmanned aerial vehicles (UAVs) with communication, computing, and storage capabilities have high mobility. Based on this advantage, it can push the service closer to the user. Our research group is concerned with implementing the Internet of Things (IoT) enabled massive crowd management platform that employs 5G to facilitate network connectivity among the UAV and sensory networks. In such a highly dynamic environment, IoT devices, users, and UAVs are the key factors to determine the caching strategies. Due to the limitations of drone batteries and changes in UAV cluster density, the environment is characterized as highly dynamic. However, the existing UAV caching strategy does not consider both the changes of the users and UAVs. Therefore, this paper proposes a three-layer UAV cache architecture in 5G network to achieve hierarchical adaptation to the dynamic changes of users and UAVs. Based on this architecture, we propose a dual dynamic adaptive caching(DDAC) algorithm. The DDAC algorithm is divided into two parts: user adaptation and UAV adaptation. For user adaptation, we designed a user-adaptive UAV trajectory model, which ensures the transmission efficiency of the UAV. For UAV adaptation, we designed and deployed a UAV-adaptive cache model based on a greedy algorithm in the cognitive center layer. The UAV can dynamically adjust the caching strategy according to the cluster density. Finally, the results of the experiment prove that our proposed UAV adaptive cache model has better performance in the cache hit ratio compared with the existing UAV cache model.

With the advantage of being close to the network, edge cloud-enabled computing mode brings flexibility to task scheduling. However, with the heterogeneity of computing resources between cloud and edge cloud, and the complexity of computing and communication processes between multi-edge cloud, challenges have been brought to the deployment and computing of tasks in cloud-edge collaborative environments. In order to solve this challenge, firstly a deep reinforcement learning controller based cloud-edge collaborative computing framework has been proposed. Then a system QoS model has been estab-lished considering both the user benefits and the service provider benefits. By using deep Q-network, a deep reinforcement learning based collaborative task placement algorithm has been proposed for dynamically optimizing the target system utility. Finally, the experimental results show that the proposed method has a good learning ability for the computing cost of cloud and edge cloud as well as the communication cost between multi-edge cloud. In addition, compared with Q-table learning, random computing and cloud computing, a 10% improvement of system utility has been achieved with the proposed method.

With the growth of participating clients, the centralized parameter server (PS) will seriously limit the scale and efficiency of Federated Learning (FL). A straightforward approach to scale up the FL system is to construct a Parallel FL (PFL) system with multiple PSes. However, it is unclear whether PFL can really achieve a faster convergence rate or not. Even if the answer is yes, it is non-trivial to design a highly efficient parameter average algorithm for a PFL system. In this paper, we propose a completely parallelizable FL algorithm called P-FedAvg under the PFL architecture. P-FedAvg extends the well-known FedAvg algorithm by allowing multiple PSes to cooperate and train a learning model together. In P-FedAvg, each PS is only responsible for a fraction of total clients, but PSes can mix model parameters in a dedicatedly designed way so that the FL model can well converge. Different from heuristic-based algorithms, P-FedAvg is with theoretical guarantees. To be rigorous, we conduct theoretical analysis on the convergence rate of P-FedAvg, and derive the optimal weights for each PS to mix parameters with its neighbors. We also examine how the overlay topology formed by PSes affects the convergence rate and robustness of a PFL system. Lastly, we perform extensive experiments with real datasets to verify our analysis and demonstrate that P-FedAvg can significantly improve convergence rates than traditional FedAvg and other competitive baselines. We believe that our work can help to lay a theoretical foundation for building more efficient PFL systems.

As an information carrier, the Internet of Things (IoT) based on the Internet and sensing equipment makes all physical objects form an interconnected network. The 5th generation mobile networks (5G) technology has many advantages, such as high data rates, reduced latency, energy savings, reduced costs, increased system capacity and large-scale device connectivity, realize the real-time data collection, transmission, analysis, management, and application in the era of global Internet of Everything. In order to quickly respond to people’s daily requirements and provide the smart application based on artificial intelligence technology in various scenarios, the number of IoT devices will further increase. The integration of mobile-edge computing (MEC) and IoT is imperative, especially in industries needing real-time data computing, such as smart home, public security, automobile transportation, smart health, emotion care, etc. As a new form of IoT terminal combining 5G and MEC, wearable device based on intelligent fabrics plays an important role in smart health and emotion care, which is one of the potential development directions of the next generation of intelligent medical and rehabilitation systems.

Currently, the integration of distributed energy generators through virtual power plants in the Internet of Energy is a mainstream method. The complex structure of virtual power plants and the characteristics of distributed energy make it difficult to solve the economic dispatch problems of virtual power plants. In addition, the load of a virtual power plant is unstable and uncertain and thus requires a robust economic dispatch strategy. Because the selection of the set of uncertain conditions is conservative, the traditional robust economic dispatch strategies cannot effectively reduce the cost of virtual power plants. In addition, the traditional methods for solving robust strategies cannot directly solve nonlinear and nonconvex problems. In this article, we propose a scenario-based robust economic dispatch strategy for virtual power plants, aiming to reduce the operational costs of virtual power plants. First, to reduce the conservatism of the strategy, scenario-based data augmentation is adopted for data generation. Through a generative adversarial network, a large amount of scene data are generated to extend the set of uncertain conditions. The scene data cannot only reduce the conservatism but also can be used in the determination of robust strategies. Second, deep reinforcement learning is adopted for historical data training, directly solving nonlinear and nonconvex problems to obtain a robust economic dispatch strategy. As experiments show, with the accurate generation of scene data, the proposed economic dispatch strategy is robust and effectively reduces the cost of virtual power plants.

The Internet of Things (IoT) enables the interconnection of new cyber–physical devices that generate significant traffic of distributed, heterogeneous, and dynamic data at the network edge. Since several IoT applications demand for short response times (e.g., industrial applications, emergency management, real-time systems, and healthcare systems) and, at the same time, rely on resource-constrained devices, the adoption of traditional data mining techniques is neither effective nor efficient. Therefore, conventional data mining techniques need to be adjusted for optimizing response times, energy consumption, and data traffic while still providing adequate accuracy as required by the IoT applications.

With the increase in natural gas consumption, distributed natural gas supply and transaction have become new development goals of the industrial Internet of Things (IoT) for natural gas. However, there are obvious disadvantages of the existing natural gas pipeline network in aspects of infrastructure warning, multilevel data transmission, automatic transaction, and security. Emerging technologies, such as blockchain, edge computing, and AI have been introduced to address these shortcomings. This article proposes Smart Micro-GaS, i.e., the concept of a cognitive micro natural gas industrial ecosystem based on mixed blockchain and edge computing. Three aspects, multilevel, multiview, and multidimension, are put forward for its design and deployment. Then, based on the most important smart contract algorithm in blockchain, a mixed transaction model for natural gas is established. Finally, a case analysis is conducted on a smart natural gas testbed for data prediction and the proposed smart contract algorithm. The framework proposed in this article makes the natural gas data have multilevel liquidity and realizes diversified transactions.

At present, computed tomography (CT) is widely used to assist disease diagnosis. Especially, computer aided diagnosis (CAD) based on artificial intelligence (AI) recently exhibits its importance in intelligent healthcare. However, it is a great challenge to establish an adequate labeled dataset for CT analysis assistance, due to the privacy and security issues. Therefore, this paper proposes a convolutional autoencoder deep learning framework to support unsupervised image features learning for lung nodule through unlabeled data, which only needs a small amount of labeled data for efficient feature learning. Through comprehensive experiments, it shows that the proposed scheme is superior to other approaches, which effectively solves the intrinsic labor-intensive problem during artificial image labeling. Moreover, it verifies that the proposed convolutional autoencoder approach can be extended for similarity measurement of lung nodules images. Especially, the features extracted through unsupervised learning are also applicable in other related scenarios.

Most of the existing mobile application (app) vetting mechanisms only estimate risks at a coarse-grained level by analyzing app syntax but not semantics. We propose a semantics-aware privacy risk assessment framework (SPRisk), which considers the sensitivity discrepancy of privacy-related factors at semantic level. Our framework can provide qualitative (i.e., risk level) and quantitative (i.e., risk score) assessment results, both of which help users make decisions to install an app or not. Furthermore, to find the reasonable weight distribution of each factor automatically, we exploit a self-learning weight assignment method, which is based on fuzzy clustering and knowledge dependency theory. We implement a prototype system and evaluate the effectiveness of SPRisk with 192,445 normal apps and 7,111 malicious apps. A measurement study further reveals some interesting findings, such as the privacy risk distribution of Google Play Store, the diversity of official and unofficial marketplaces, which provide insights into understanding the seriousness of privacy threat in the Android ecosystem.

Future industrial cyber-physical system (CPS) devices are expected to request a large amount of delay-sensitive services that need to be processed at the edge of a network. Due to limited resources, service placement at the edge of the cloud has attracted significant attention. Although there are many methods of design schemes, the service placement problem in industrial CPS has not been well studied. Furthermore, none of existing schemes can optimize service placement, workload scheduling, and resource allocation under uncertain service demands. To address these issues, we first formulate a joint optimization problem of service placement, workload scheduling, and resource allocation in order to minimize service response delay. We then propose an improved deep Q-network (DQN)-based service placement algorithm. The proposed algorithm can achieve an optimal resource allocation by means of convex optimization where the service placement and workload scheduling decisions are assisted by means of DQN technology. The experimental results verify that the proposed algorithm, compared with existing algorithms, can reduce the average service response time by 8-10%.

The potential for the wide-scale acceptance of the Industrial IoT is limited by a lack of automation, real-time monitoring, and connectedness. However, the future communication trend towards 5G is expected to bring greater benefits to IIoT infrastructures in terms of high-speed transmission and ultra-low latency. Furthermore, with emerging techniques such as millimeter-wave (mmWave), massive multiple-input multiple-output (MIMO), and machine-to-machine (M2M) communications, the coupling of IIoT and 5G will advance profoundly. Despite these advantages, 5G-envisioned IIoT ecosystems are expected to face other potential concerns such as trust, security, and privacy. Apart from this, the challenges related to data storage and processing and computational complexities will also draw significant attention. To address the above-mentioned challenges, it's important to analyze data in real-time. In this direction, transfer learning (TL) can be a revolutionary breakthrough. TL fosters greater explorations and experimentations, leading to innovations and greater productivity.

Depression is the result of a complex interaction of social, psychological and physiological elements. Research into the brain disorders of patients suffering from depression can help doctors to understand the pathogenesis of depression and facilitate its diagnosis and treatment. Functional near-infrared spectroscopy (fNIRS) is a non-invasive approach to the detection of brain functions and activities. In this paper, a comprehensive fNIRS-based depression-processing architecture, including the layers of source, feature and model, is first established to guide the deep modeling for fNIRS. In view of the complexity of depression, we propose a methodology in the time and frequency domains for feature extraction and deep neural networks for depression recognition combined with current research. It is found that compared to non-depression people, patients with depression have a weaker encephalic area connectivity and lower level of activation in the prefrontal lobe during brain activity. Finally, based on raw data, manual features and channel correlations, the AlexNet model shows the best performance, especially in terms of the correlation features and presents an accuracy rate of 0.90 and a precision rate of 0.91, which is higher than ResNet18 and machine-learning algorithms on other data. Therefore, the correlation of brain regions can effectively recognize depression (from cases of non-depression), making it significant for the recognition of brain functions in the clinical diagnosis and treatment of depression.

This paper comprehensively discusses the cooperative communication and computation of vehicular system. Based on the cooperative transmission, an stochastic model of vehicle-to-vehicle (V2V) communication reliability is established using probability theory. Furthermore, the computation reliability is defined as a new metric for computation offloading, and a vehicle computational performance evaluation model is also established. In order to effectively compute the required data, we combine V2V communication and vehicle computing to further characterize the coupling reliability of cooperative communications and computation systems. In addition, we propose a virtual queue model that combines queue length and vehicle privacy entropy to optimize partitioning. Finally, considering the amount of processing data and cut-off time of vehicle applications, we establish the optimal partition model of vehicle computing with the goal of maximizing the coupling reliability, and propose the coupling-oriented reliability calculation for vehicle collaboration using dynamic programming methods. Simulations show that the proposed scheme outperforms traditional approaches in terms of coupling reliability and completion rate. In addition, the allocation between local computing and data offloading is controlled by the server’s privacy perception of collaboration events.

The autonomous vehicular technology is approaching a level of maturity that gives confidence to end-users in many cities around the world for their usage so as to share the roads with manual vehicles. Autonomous and manual vehicles have different capabilities which may result in surprising safety, security, and resilience impacts when mixed together as a part of the intelligent transportation system (ITS). For example, autonomous vehicles can communicate electronically with one another, make fast decisions and associated actuation, and generally act deterministically. In contrast, manual vehicles cannot communicate electronically, are limited by the capabilities and slow reaction of human drivers, and may show some uncertainty and even irrationality in behavior due to the involvement of humans. At the same time, humans can react properly to more complex situations than autonomous vehicles. Unlike manual vehicles, the security of computing and communications of autonomous vehicles can be compromised thereby precluding them from achieving individual or group goals.

With the development of smart cities, Internet services will be pervasively accessible for moving vehicles. It is envisioned that the video content demand of vehicles will explode in the near future. However, the strategy to efficiently distribute video content in large-scale vehicular networks is still absent due to challenges arising from the huge video population, heavy bandwidth consumption, heterogeneous user devices, and vehicles’ mobility. In this work, we propose to collaboratively replicate video content on Roadside Units (RSUs) to enhance video distribution services based on the fact that the contact period between moving vehicles and a single RSU is not long enough to complete video downloading. In our design, a video file is split into multiple chunks. Each RSU replicates a small number of original chunks and chunks encoded by network coding. Replicating encoded chunks can reduce redundancy of chunks on different RSUs so that RSUs can complement each other better, whereas original chunks can be transrated to chunks with lower bitrates flexibly to fit in users’ devices. Therefore, we replicate both original and encoded chunks on RSUs to take advantages of both sides. Stochastic models are employed to analyze chunk download processes and a convex optimization problem is formulated to determine the optimal partition of space allocated to each kind of chunks. Furthermore, we extend our strategy to support video streaming services and empirically prove that the influence caused by limitations of network coding is moderate. In the end, we conduct extensive simulations which not only validate the accuracy of our models but also demonstrate that our strategy can effectively boost video distribution services.

Autism spectrum disorder (ASD) is a serious hazard to the physical and mental health of children, which limits the social activities of patients throughout their lives and places a heavy burden on families and society. The developments of communication techniques and artificial intelligence (AI) have provided new potential methods for the treatment of autism. The existing treatment systems based on AI for children with ASD focus on detecting health status and developing social skills. However, the contradiction between the terminal interaction capability and availability cannot meet the needs for real application scenarios. At the same time, the lack of diverse data cannot provide individualized care for autistic children. To explore this robot-based approach, a novel AI-based first-view-robot architecture is proposed in this article. By providing care from the first-person perspective, the proposed wearable robot overcomes the difficulty of the absence of cognitive ability in the third-view of traditional robotics and improves the social interaction ability of children with ASD. The first-view-robot architecture meets the requirements of dynamic, individualized, and highly immersed interaction services for autistic children. First, the multi-modal and multi-scene data collection processes of standard, static, and dynamic datasets are introduced in detail. Then, to comprehensively evaluate the learning ability of children with ASD through mental states and external performances, a learning assessment model with emotion correction is proposed. Besides, a wearable robot-assisted environment perception and expression enhancement mechanism for children with ASD is realized by reinforcement learning, which can be adapted to interactive environments with optimal action policies. An interactive testbed for children with ASD treatments is demonstrated and experimental cases for test subjects are presented. Last, three open issues are discussed from data processing, robot designing, and service responding perspectives.

In recent years, the rapid growth of traffic has become a serious problem of mobile network operators. For effectively mitigating this traffic explosion problem, there have been many efforts to research on offloading the traffic from cellular links to direct communications among users. In this paper, we are motivated by users' sharing activities, and hence propose the framework of Traffic Offloading assisted by Social network services (SNS) via opportunistic Sharing in mobile social networks (MSNs), TOSS, to offload SNS-based cellular traffic by user-to-user sharing. First, a subset of users who are to receive the same content was selected as initial population depending on their content spreading impacts in the online SNSs and their mobility patterns in the offline MSNs. Then users move, encounter and share the content via opportunistic local connectivity with each other, the content via opportunistic local connectivity with each other, e.g., Bluetooth, Wi-Fi Direct, Device-to-Device in LTE. Individual users have distinct access patterns, which potentially allow TOSS to exploit the user-dependent access delay between the content generation time and each user's access time for content sharing purposes. The traffic offloading and content spreading among users are analyzed by taking into account various options in linking SNS and MSN traces. Four mobility traces and online SNS trace for evaluation are analyzed. An extended evaluation over a large-scale data set are further carried out, and the effectiveness of TOSS is further proved.

With the advent of the Internet era, the trend of highly informed society has been becoming more and more obvious, and the requirement of society on communication is also increasing. flexible satellite communication mode has many advantages such as large communication load and no geographic restriction, which cannot be replaced by other communication modes. In the satellite communication system, the most important is the satellite earth station (SES). When receiving signals from the target satellite, the SES terminal must accurately point to the satellite and track it to obtain the maximum receiving signal and reduce the interference with other signals simultaneously. However, the motion of either satellite or terminal can cause a change in signal intensity, so it is necessary to adjust the pointing of the SES antenna in time to maintain optimal signal receiving conditions. In order to satisfy different satellite communication scenarios, in this paper, Artificial intelligent (AI) technology is applied to the satellite communication process, mainly to optimize the optimal antenna angle and time consumption reduction. Firstly, the process of antenna pointing is introduced, and the traditional antenna search algorithm Auto-Acqire algorithm (AA algorithm) is analyzed in detail. Considering that the satellite system needs to adapt to the communication requirements of different terminals, based on AI antenna pointing algorithms are proposed. In order to verify this research, we build an experimental platform and compare the traditional AA algorithm as a benchmark algorithm with FI-GRU and II-DRL algorithms. According to the experimental results, the two algorithms proposed in this paper can improve the efficiency of satellite pointing and tracking tasks.

With the development of software-defined network (SDN), there will be a large number of devices to access network, which may cause an incalculable burden to the communication network. In addition, due to the high bandwidth in the fifth-generation (5G) era, innovation will occur in different fields. There are not only strict requirements on the communication capability of SDN for these application scenarios but also a lot of computing resources. For massive access devices, it is difficult for the traditional service resource scheduling and the allocation system to meet user demand growth. To address the above-stated problems, an artificial intelligence agent (AI Agent) system is put forth in this article. AI Agents can be deployed in different layers of the SDN, thus realizing functions like network service prediction and resource scheduling. A brand new AI Agent framework is designed, and an AI algorithm is adopted to replace the traditional service prediction and resource scheduling strategies. In the meantime, a relevant agent deployment scheme is put forward. Finally, an AI Agent-based simulation experiment for resource scheduling is designed, and the accuracy in network service prediction and rationality in resource allocation based on this framework are tested. The experimental result showed that the operation efficiency of the SDN can be effectively improved, and the resource hit ratio and user service quality may be improved with AI-agent-based traffic prediction and resource allocation model.

With the development of Internet of Things (IoT) and communication technology, the number of next-generation IoT devices has increased explosively, and the delay requirement for content requests is becoming progressively higher. Fortunately, the edge-caching scheme can satisfy users' demands for low latency of content. However, the existing caching schemes are not smart enough. To address these challenges, we propose a human-like hybrid caching architecture based on the software-defined edge cloud, which simultaneously considers the content popularity and the fine-grained user characteristics. Then, an optimization problem with a caching hit ratio as an optimization objective is formulated. To solve this problem, using reinforcement learning, we design a human-like hybrid caching algorithm. The extensive experiments show that compared with popular caching schemes, human-like hybrid caching schemes can improve the cache hit ratio by 20%.

With the popularity of wearable devices, along with the development of clouds and cloudlet technology, there has been increasing need to provide better medical care. The processing chain of medical data mainly includes data collection, data storage and data sharing, etc. Traditional healthcare system often requires the delivery of medical data to the cloud, which involves users' sensitive information and causes communication energy consumption. Practically, medical data sharing is a critical and challenging issue. Thus in this paper, we build up a novel healthcare system by utilizing the flexibility of cloudlet. The functions of cloudlet include privacy protection, data sharing and intrusion detection. In the stage of data collection, we first utilize Number Theory Research Unit (NTRU) method to encrypt user's body data collected by wearable devices. Those data will be transmitted to nearby cloudlet in an energy efficient fashion. Second, we present a new trust model to help users to select trustable partners who want to share stored data in the cloudlet. The trust model also helps similar patients to communicate with each other about their diseases. Third, we divide users' medical data stored in remote cloud of hospital into three parts, and give them proper protection. Finally, in order to protect the healthcare system from malicious attacks, we develop a novel collaborative intrusion detection system (IDS) method based on cloudlet mesh, which can effectively prevent the remote healthcare big data cloud from attacks. Our experiments demonstrate the effectiveness of the proposed scheme.

In this paper, we propose a label-less learning for emotion cognition (LLEC) to achieve the utilization of a large amount of unlabeled data. We first inspect the unlabeled data from two perspectives, i.e., the feature layer and the decision layer. By utilizing the similarity model and the entropy model, this paper presents a hybrid label-less learning that can automatically label data without human intervention. Then, we design an enhanced hybrid label-less learning to purify the automatic labeled data. To further improve the accuracy of emotion detection model and increase the utilization of unlabeled data, we apply enhanced hybrid label-less learning for multimodal unlabeled emotion data. Finally, we build a real-world test bed to evaluate the LLEC algorithm. The experimental results show that the LLEC algorithm can improve the accuracy of emotion detection significantly.

Confronting with the sheer amount of Over-the-Top (OTT) videos, personalized recommendation is especially important for users to locate videos of interest. However, previous approaches seldom considered the influence of watching time when designing video recommendation algorithms. In this paper, we first conduct a detailed measurement study on a leading OTT video service provider in China and our results show that user view preferences are substantially influenced by watching time. Based on the above results, we further propose a personalized time-aware video recommendation algorithm called TAMF for OTT videos. The basic idea of our proposed TAMF algorithm is to utilize matrix factorization to unveil how watching time affects user view interests and cluster time slots with similar influence. In this way, we can collaboratively learn users' personal interests if their views belong to the same cluster, and precisely capture user view preferences with watching time. Finally, we also conduct extensive experiments using real traces to evaluate the performance of our algorithm, and the experimental results show that our proposed algorithm can improve video recommendation performance by 4.83% and 4.42% in terms of WMRR and WMAP respectively and significantly boost user engagement.

With the development of communication technology and the explosive growth of video traffic brought by the rapid growth of mobile devices (such as smartphones and wearable devices), great business opportunities have been brought to video service providers. In this paper, we make full use of the cache and computing capacity of edge cloud. Considering the multi bitrate of video, we design the video caching and processing model that offers maximized profit to video service provider. Specifically, we model this problem as the 0-1 optimization problem and design the learning-based online upper confidence bound algorithm based on multi-arm bandit theory. This algorithm can design the corresponding cache and process strategy in real time according to the users' request to video. Furthermore, this strategy can maximize the profit of video provider and satisfy the service quality for users. Finally, experimental results show that our proposed video caching and processing scheme is superior to other schemes.

With energy scarcity and environmental pollution becoming increasingly serious, the accurate estimation of fuel consumption of vehicles has been important in vehicle management and transportation planning toward a sustainable green transition. Fuel consumption is calculated by fuel-level data collected from high-precision fuel-level sensors. However, in the vehicle monitor platform, there are many types of error in the data collection and transmission processes, such as the noise, interference, and collision errors that are common in the high speed and dynamic vehicle environment. In this paper, an effective method for cleaning and repairing the fuel-level data is proposed, which adopts the threshold to acquire abnormal fuel data, the time quantum to identify abnormal data, and linear interpolation based algorithm to correct data errors. Specifically, a modified Gaussian mixture model (GMM) based on the synchronous iteration method is proposed to acquire the thresholds, which uses the particle swarm optimization algorithm and the steepest descent algorithm to optimize the parameters of GMM. The experiment results based on the fuel-level data of vehicles collected over one month prove that the modified GMM is superior to GMM-expectation maximization on fuel-level data, and the proposed method is effective for cleaning and repairing outliers of fuel-level data.

The interactive robot is expected to support emotion analysis and utilize the deep learning and machine learning to provide users with continuous emotional care. However, it is a great challenge to securely acquire sufficient data for emotion analysis such that the privacy of emotional data is adequately protected. To address the security issue, this paper proposes a security policy based on identity authentication and access control to ensure the security certificate through an interactive robot or edge devices while the access control of private data stored in the edge cloud is adequately protected. Specifically, this paper adopts a polynomial-based access control policy and designs a secure and effective access control scheme. At the same time, this paper puts forward an identity authentication mechanism in view of edge cloud systems, which can reduce the computational overhead and authentication delay in a collaborative authentication of multiple edge clouds. The effectiveness of the proposed access control policy and identity authentication mechanism is verified by an actual testbed platform.

Driven by the vision of edge computing and the success of rich cognitive services based on artificial intelligence, a new computing paradigm, edge cognitive computing (ECC), is a promising approach that applies cognitive computing at the edge of the network. ECC has the potential to provide the cognition of users and network environmental information, and further to provide elastic cognitive computing services to achieve a higher energy efficiency and a higher Quality of Experience (QoE) compared to edge computing. This article first introduces our architecture of the ECC and then describes its design issues in detail. Moreover, we propose an ECC-based dynamic service migration mechanism to provide insight into how cognitive computing is combined with edge computing. In order to evaluate the proposed mechanism, a practical platform for dynamic service migration is built up, where the services are migrated based on the behavioral cognition of a mobile user. The experimental results show that the proposed ECC architecture has ultra-low latency and a high user experience, while providing better service to the user, saving computing resources, and achieving a high energy efficiency.

Vehicular ad hoc networks (VANETs) have a potential to promote vehicular telematics and infotainment applications, where a key and challenging issue is the design of robust and efficient vehicular content transmissions to combat the lossy inter-vehicle links. In this paper, we focus on the robust optimization of content transmissions over cooperative VANETs. We first derive a stochastic model for estimation of time-varying inter-vehicle distance, which is dependent of the vehicle real-time kinematics and the distribution of the initial space headway. With this model, we analytically formulate the transient inter-vehicle connectivity assuming Nakagami fading channels for the physical (PHY) layer. We also model the contention nature of the medium access control (MAC) layer, on which we are based to evaluate the throughput achieved by each vehicle equipped with dedicated short-range communication (DSRC). Combining these models, we derive a closed-formed expression for the upper bound of the probability of failure in intact-content transmissions. Based upon this theoretical bound, we develop a robust optimization model for assigning content data traffic among different cooperative transmission paths, where the objective is to minimize the maximum likelihood of unsuccessful content transmissions over the cooperative VANET. We mathematically transform the optimization model to another equivalent form, such that it can be practically deployed. Finally, we validate our theoretical development with extensive simulations. Numerical results are also provided to confirm the power of cooperation in boosting the VANET performance as well as demonstrate the advantage of the proposed robust optimization in terms of content data reception reliability.

With the advance of cloud computing and 4G/5G technology, video contents recorded by in-car cameras (i.e., vehicular digital video recorders) can be uploaded to the cloud to facilitate accident analysis, online surveillance, video sharing, etc. However, the cost of uploading such huge volume of video contents via unstable vehicular access networks (including cellular base stations and road-side units) can be considerable by considering the increasing video quality requirement, time constraint, and limited local buffer space. In this paper, we propose an adaptive video recording and uploading scheme to maximize the overall utility of cloud-based in-car video uploading over vehicular access networks. Specifically, the utility function is defined as the weighted sum of bandwidth cost and video quality and we formulate the problem into a constrained Markov decision process (MDP). Based on the theoretic foundation of MDP, we design and implement an algorithm to obtain an adaptive chunk uploading policy for video contents over vehicular access networks. Extensive simulations have been conducted to demonstrate that our policy can achieve the best performance compared with other alternative strategies.

As for deployment of security strategy, corresponding forwarding rules for switches can be given in allusion to different traffic conditions. However, due to lack of global cognitive control for security strategy deployment in traditional Internet of Vehicles (IoV), it is quite difficult to realize global and optimized security strategy deployment scheme so as to meet security requirements in different traffic conditions. On basis of traditional IoV, cognitive engine is added in cognitive IoV (CIoV) to enhance the intelligence of traditional IoV. In allusion to CIoV, and in consideration of restrictions on transmission delay, the security strategy deployment for switches on core network is formulated in this paper, thus not only the safe transmission rules are met, but the transmission delay can also be the lowest. To be specific, the path selection of switches is modeled as 0-1 programming problem in this paper, and that optimization problem is proved to be a nonconvex optimization problem. Then we convert that problem into a convex optimization problem by log-det heuristic algorithm, thus to give path selection scheme to meet security requirements with the lowest delay on the whole. Experiment proves that cognitive engine-based security strategy deployment put forth in this paper is much better than other schemes.

Vehicular ad hoc networks (VANETs) can help reduce traffic accidents through broadcasting emergency messages among vehicles in advance. However, it is a great challenge to timely deliver the emergency messages to the right vehicles which are interested in them. Some protocols require to collect nearby real-time information before broadcasting a message, which may result in an increased delivery latency. In this paper, we proposed an improved position-based protocol to disseminate emergency messages among a large scale vehicle networks. Specifically, defined by the proposed protocol, messages are only broadcasted along their regions of interest, and a rebroadcast of a message depends on the information including in the message it has received. The simulation results demonstrate that the proposed protocol can reduce unnecessary rebroadcasts considerably, and the collisions of broadcast can be effectively mitigated.

Cognitive Internet of Things (IoT) is the use of cognitive computing technologies, which is derived from cognitive science and artificial intelligence, in combination with data generated by connected devices and the actions those devices can perform. Cognitive IoT provides high performance of communicating, computing, controlling, and even high degree of machine intelligence. Cognitive IoT redefines the relationship between human and their pervasive digital environment. They may play the role of assistant or coach for the user. Specifically, the IoT generated big data, when used to power predictive analytics algorithms or to develop a corps for a cognitive computing solution, can provide insights that would never be discovered in time to be useful if the departmental silos do not collaboration in data sensing and analysis. It is the integration of this data that enables cognitive computing applications for IoT of the next decade. Therefore, the services of a cognitive IoT could be constructive, prescriptive, or instructive in nature.

With the development of recent innovative applications (e.g., augment reality, self-driving, and various cognitive applications), more and more computation-intensive and data-intensive tasks are delay-sensitive. Mobile edge computing in ultra-dense network is expected as an effective solution for meeting the low latency demand. However, the distributed computing resource in edge cloud and energy dynamics in the battery of mobile device makes it challenging to offload tasks for users. In this paper, leveraging the idea of software defined network, we investigate the task offloading problem in ultra-dense network aiming to minimize the delay while saving the battery life of user's equipment. Specifically, we formulate the task offloading problem as a mixed integer non-linear program which is NP-hard. In order to solve it, we transform this optimization problem into two sub-problems, i.e., task placement sub-problem and resource allocation sub-problem. Based on the solution of the two sub-problems, we propose an efficient offloading scheme. Simulation results prove that the proposed scheme can reduce 20% of the task duration with 30% energy saving, compared with random and uniform task offloading schemes.

As a major strategy to ensure the safety of IT infrastructure, anomaly detection plays a more important role in cloud computing platform which hosts the entire applications and data. On top of the classic Markov chain model, we proposed in this paper a feasible multi-order Markov chain based framework for anomaly detection. In this approach, both the high-order Markov chain and multivariate time series are adopted to compose a scheme described in algorithms along with the training procedure in the form of statistical learning framework. To curb time and space complexity, the algorithms are designed and implemented with non-zero value table and logarithm values in initial and transition matrices. For validation, the series of system calls and the corresponding return values are extracted from classic Defense Advanced Research Projects Agency (DARPA) intrusion detection evaluation data set to form a two-dimensional test input set. The testing results show that the multi-order approach is able to produce more effective indicators: in addition to the absolute values given by an individual single-order model, the changes in ranking positions of outputs from different-order ones also correlate closely with abnormal behaviours.

Advances in future computing to support emerging sensor applications are becoming more important as the need to better utilize computation and communication resources and make them energy efficient. As a result, it is predicted that intelligent devices and networks, including mobile wireless sensor networks (MWSN), will become the new interfaces to support future applications. In this paper, we propose a novel approach to minimize energy consumption of processing an application in MWSN while satisfying a certain completion time requirement. Specifically, by introducing the concept of cooperation, the logics and related computation tasks can be optimally partitioned, offloaded and executed with the help of peer sensor nodes, thus the proposed solution can be treated as a joint optimization of computing and networking resources. Moreover, for a network with multiple mobile wireless sensor nodes, we propose energy efficient cooperation node selection strategies to offer a tradeoff between fairness and energy consumption. Our performance analysis is supplemented by simulation results to show the significant energy saving of the proposed solution.

Location-based service (LBS) has gained increasing popularity recently, but protecting users' privacy in LBS remains challenging. Depending on whether a trusted third party (TTP) is used, existing solutions can be classified into: TTP-based and TTP-free. The former relies on a TTP for user privacy protection, which creates a single-point-failure and is thus impractical in reality. The latter does not require any TTP, but usually introduces redundant point-of-interest (POI) records in query result and thus incurs significant computation and communication costs on the user side, making them unsuitable for resource-constrained mobile devices. In this paper, we propose a novel framework to protect user privacy while ensuring efficiency. Our framework also uses redundant POI records to protect privacy against LBS provider but employs a semi-trusted third party, called proxy, to filter out redundant POI records. To protect privacy against proxy, we design a novel filtering protocol, Blind filter, to allow the proxy to filter out redundant encrypted POI records in a blind way. In comparison with existing solutions, our framework is not only resilient to dual identity attack, but also incurs lower communication and computation overhead. Comprehensive analysis and experiments show that our framework is secure and highly efficient in mobile environments.

The knowledge of view preferences of users is crucial for online video providers to improve their system operations and video recommendations. However, it is challenging to accurately acquire this knowledge by merely relying on a single online video system. In this paper, we conduct a joint statistical study using the cross-platform information obtained from Douban, the largest online video database with video rating functionality in China, and Youku, one of the largest online video streaming systems in China. The Douban dataset includes feedbacks (e.g., movie ratings, comments, and reviews) from all users of different online video systems, and movie metadata (e.g., release date, actors, and directors), based on which we can statistically explore effective and significant factors attributing to video view counts. Meanwhile, our study unveils user behaviors that are latent when only observing a single video system. Finally, a multiple correlation analysis reveals that factors extracted from Douban can significantly increase our ability to predict video view counts. Our study can benefit video caching, video procurement, and advertisement campaign for online video providers.

With the growing popularity of mobile devices, a new type of peer-to-peer communication mode for mobile cloud computing has been introduced. By applying a variety of short-range wireless communication technologies to establish connections with nearby mobile devices, we can construct a mobile cloudlet in which each mobile device can either works as a computing service provider or a service requester. Although the paradigm of mobile cloudlet is cost-efficient in handling computation-intensive tasks, the understanding of its corresponding service mode from a theoretic perspective is still in its infancy. In this paper, we first propose a new mobile cloudlet-assisted service mode named Opportunistic task Scheduling over Co-located Clouds (OSCC), which achieves flexible cost-delay tradeoffs between conventional remote cloud service mode and mobile cloudlets service mode. Then, we perform detailed analytic studies for OSCC mode, and solve the energy minimization problem by compromising among remote cloud mode, mobile cloudlets mode and OSCC mode. We also conduct extensive simulations to verify the effectiveness of the proposed OSCC mode, and analyze its applicability. Moreover, experimental results show that when the ratio of data size after task execution over original data size associated with the task is smaller than 1 (i.e.,r<; 1) and the average meeting rate of two mobile devices λ is larger than 0:00014, our proposed OSCC mode outperforms existing service modes.

Many vehicular ad hoc applications rely on vehicular broadcasting-based multi-hop routing to disseminate messages. In this work, we study the question of vehicular broadcasting-based routing. In particular, by modelling the vehicular message dissemination with a limited-time epidemic dynamics, we propose an online self-adaptive beaconing method to dynamically learn the optimal beaconing policy for vehicular broadcasting with consideration of varying opportunistic contacts between vehicles. The vehicular broadcasting incorporated within the proposed method can ensure message delivery with low dissemination delay and routing cost. Both theoretical analysis and simulation results are provided to exhibit the robustness and effectiveness of the proposed solution and the significantly performance with respect to the conventional solution.

The online video streaming service is of huge market values with billions of worldwide users. For online video providers, e.g., Netflix, Youku, the crucial question is how to understand users' view behaviors and preferences because this knowledge is important for their business operation. Existing solutions mainly rely on analyzing users' historical view records, which however are not always available, especially for new videos and unprovided videos. Different from existing solutions, we propose to infer user behaviors and preferences by jointly analyzing data collected from multiple platforms (e.g., video streaming systems, video databases, etc.). In particular, we use the movie data crawled from a leading video streaming system (i.e., Youku), and a well-known video database in China (i.e., Douban) for this study. Our investigation points out that movie quality (evaluated in terms of Douban scores) and release date jointly influence viewers' preferences. In addition, we reveal a series of user behaviors, e.g., users are reluctant to post comments or ratings for movies they do not like, and user eyeballs are heavily captured by new movies. Understanding of these user behaviors covered by this study is essential for video recommendation and video popularity prediction which can benefit video procurement and advertisement campaign.

In Video Coding, the Rate Distortion Optimization (RDO) is the key technique to choose the most efficient coded representation of raw video. Specifically, encoder selects an optimal combination of coding parameters from a fixed and discrete candidate set in the rate-distortion sense. As this process is computation intensive essentially, its practicality can be limited especially for real-time applications. Thus, it is worthwhile to reduce the complexity while still preserve its accuracy. To achieve this goal, we propose an efficient and low-complexity model to estimate the rate and distortion information. A CG level content-adaptive rate model is proposed to ensure the bit rate estimation is accurate and stable against the change of coding parameters and video content. For distortion modeling, an efficient quantization-free estimator is proposed. Extensive experimental results demonstrate that our method significantly reduces in average 34.6% of encoder complexity than existing works with marginal RD performance loss.

In recent years, empowered by rich media generation devices and convenient Internet access, Crowdsourced Live Game Video Streaming (CLGVS) has become one of the most popular Internet services. Twitch.tv, the most well-known CLGVS platform in the world, allows gamers to broadcast their gaming videos over the Internet. With the prevalence of mobile devices, viewers can watch gamers playing video games anywhere, anytime, on any devices (e.g., smartphones, tablets, or personal computers). However, the heterogeneity of user devices makes conventional solutions hard to ensure user-perceived quality. In this paper, we address the problem of cost-effective adaptive live game video streaming from the perspective of CLGVS service providers. Our purpose is to minimize the operational cost for CLGVS service providers by making live transcoding decisions, bit-rate adaptation decisions, and datacenter assignment decisions dynamically. Meanwhile, our algorithm also ensures good-enough service quality for viewers. Due to the diversity of game genres, we also consider game genres when designing our algorithm. To achieve the above purpose, we formulate the problem into a constrained stochastic optimization problem. By leveraging the Lyapunov optimization framework, we derive the online strategy with provable performance bound. To evaluate the effectiveness of our proposed algorithm, we further conduct a series of trace-driven simulations. The experimental results demonstrate the effectiveness of our algorithm in terms of operational cost and service quality. Our proposed algorithm can reduce operational cost by up to 50% while achieving good-enough viewer QoE compared with other alternatives.

The expected advanced network explorations and the growing demand for mobile data sharing and transferring have driven numerous novel applications in Cyber-Physical Systems (CPSs), such as Intelligent Transportation Systems (ITSs). However, current ITS implementations are restricted by the conflicts between security and communication efficiency. Focusing on this issue, this article proposes a Security-Aware Efficient Data Sharing and Transferring (SA-EAST) model, which is designed for securing cloud-based ITS implementations. In applying this approach, we aim to obtain secure real-time multimedia data sharing and transferring. Our experimental evaluation has shown that our proposed model provides an effective performance in securing communications for ITS.

With the drastic increase of mobile devices, there are more and more mobile traffic and repeated requests for content. In 5G networks, small cell base stations (SBSs) caching and caching in wireless device-to-device network can effectively decrease the mobile traffic during peak hours. Currently, most of the related work is focused on how to cache content on SBSs and on mobile devices, and it is assumed that the user can download the entire requested content through the connected SBSs and mobile devices. However, few works have taken user mobility and the randomness of contact duration into consideration. How to improve the caching strategy by exploiting user mobility is still a challenging problem. Thus, in this paper, we first investigate the problem of how to conduct caching placement on SBS and on mobile devices leveraging user mobility, aiming to maximize the cache hit ratio. Specifically, the caching placement on SBSs and on mobile devices is formulated as an integer programming problem, and submodular optimization is adopted to solve the formulated problem. Then, we give the optimal transmission power of SBSs and mobile devices to deliver the caching content in order to reduce the energy cost. Simulation results prove that our caching strategy is more efficient than other existing caching strategies in terms of both cache hit ratio and energy efficiency.

This paper evaluates the energy efficiency of uplink transmission in heterogeneous cellular networks (HetNets), where fractional power control (FPC) is applied at user equipments (TIEs) subject to a maximum transmit power constraint. We first consider an arbitrary deterministic HetNet and characterize the properties of energy efficiency for TIEs in different path loss regimes, or different access regions. By introducing the notion of transfer path loss, we reveal that, for TIE whose path loss is below the transfer path loss, its energy efficiency highly depends on the value of power control coefficient adopted by FPC. In contrast, for TIE with path loss above the transfer path loss, the uplink energy efficiency asymptotically decreases inversely with path loss, independent of the adopted power control coefficient. Based on these properties, we characterize the optimal power control coefficients for maximizing the energy efficiency of FPC in different access regions. Next, we extend the analysis to stochastic HetNets where TIEs and BSs are distributed as independent Poisson point processes, and investigate the distribution of transmit power for uplink TIEs. Moreover, the probability of truncation outage due to constrained maximal transmit power, as well as the average energy efficiency of TIEs are analytically derived as functions of the BS and TIE densities, power control coefficient, and receiver threshold. Simulation results validate the analytical results, show the consistency between deterministic and stochastic analyses, and suggest suitable power control coefficient for achieving energy efficient uplink transmission by FPC in HetNets.

With the ever-growing number of users enjoying online video service in mobile environments, video streaming services have been dominating the mobile traffic. It can be predicted that a small improvement in the user's watching experience will cause a substantial leap in profitability in terms of content providers and distributors, network operators and service providers for mobile videos. Though recent years have witnessed effective efforts to improve a user's video quality of experience (QoE) by the use of big data for analyzing users' viewing behaviors based on large-scale, video- viewing history datasets, it is very challenging to precisely analyze users' hidden intents and feelings when they are watching online videos. In addition to obtain a better video QoE, we propose to introduce user's emotional reactions into QoE assessment. In this scheme, first, the user's mood is detected in a real time fashion via emotion detection networking. Then, a mood matching process is performed to gain the similarity of the user's intent and the video content property in terms of emotion design. Finally, a novel, decision tree-based adjustment model is proposed to characterize the relationship between QoE and various factors, including buffer ratio, average bitrate, and the user's emotions. Our study opens a road for improving video QoE based on emotion detection networking.

Mobile social networks have gained tremendous popularity among hundreds of millions of Internet users due to their fast information spreading and strong inter-person influence. However, the high complexity of social interactions and the intrinsic dynamics of mobile social networks make it challenging to model the spreading mechanism delicately and enable precise prediction of information diffusion. In this paper, we are the first to exploit physical hydrodynamics to model the process of information diffusion in mobile social networks. With our proposed hydrodynamic information diffusion prediction model (hydro-IDP), we can accurately capture the information diffusion process from both temporal and spatial perspectives, and shed more light on the information spreading characteristics (e.g., information popularity, user influence, social platform diffusivity, etc.). We also conduct a large-scale trace-driven validation to verify the accuracy of our model. The results show that the hydro-IDP model is competent to characterize and predict the process of information propagation in mobile social networks.

Multimedia transmissions for IoT (Internet-of-Things) sensing has a high demand of route capacity and tight requirements of end-to-end delay. In this paper, we address the problems on how to guarantee delay-related QoS requirements and to balance the energy consumption, while using multipath routing to offer high transmission capability for IoT multimedia sensing. This motivates us to design a Multipath Planning for Single-Source based transmissions routing scheme, namely MPSS, which establishes desirable multiple route paths following B-spline trajectories based on geographical information of source and sink node, sending and receiving angles, and inter-path distance. We further utilize a factor of hop distance to reduce the cumulated error of each hop due to the density of nodes, and to guarantee the delay-related QoS requirements. A Multipath Planning for Multi-Source routing scheme is also designed, namely MPMS, to assign the angle scope according to the source node's priority and traffic. Experimental results show that MPSS can effectively generate well-patterned multiple spline-based routes, and the end-to-end delay is under control according to the delay QoS requirement, while the total energy consumption is minimized.

Key Management protocol is one of the most important mechanisms for communication security, whereas its security analysis is critical to evaluate the information security. In this paper, we study a kind of group key management schemes which use key calculation in rekeying. At first, the security vulnerability in Code for Key Calculation (CKC) is analyzed. The codes in the key tree can be exposed to the user who should not get them. Thus, the user can get additional key information in group key updating process. Moreover, the user can continue to get the communication contents after he/she leaves the group. Sequentially, we construct two effective attacks and discuss the condition of successful attack. We analyze similar problems in other schemes. Finally, we propose an improved scheme to CKC, named Non-Code-aided Key Calculation (NCKC). Performance analysis and simulation results show that NCKC can fulfill forward and backward security at the cost of a little increase in communication overhead.

Dense heterogeneous cellular networks (HCNs) with energy harvesting nodes are promising solutions to meet both the capacity and energy efficiency needs in the next generation cellular networks. This paper studies the system performance of both energy harvesting and information receiving in a K-tier cellular networks with time-switching simultaneous wireless information and power transfer (SWIPT). Based on stochastic geometry theory, we derive the closed-form formulas for the average harvested energy, the average transmission rate and the total power and information gains. Moreover, we propose a scheme that can optimally adjust the bias factors of tier selection while leveraging the system between energy harvesting and information receiving.

Abstract With the dramatic development of social network applications, such as the Facebook, Twitter, and MySpace, privacy‐preserving problem is getting increasingly concerned. Apart from node information, researchers have found that structure information can also leak data providers' privacy, especially in weighted social networks. However, most of the existing private‐preserving schemes focus on a single aspect. The comprehensive consideration introduces two challenges. On one hand, the different anonymity demands of node and structure information lead to the collision of different design criteria, which is called as consistency matching problem. On the other hand, the simple combination of existing schemes may introduce large amounts of unnecessary changes, which makes the published information meaningless. Thus, we must find the balance between anonymity demands and changes, which is called as optimization trade‐off problem. In this paper, we propose aγ‐Strawman privacy‐preserving scheme in weighted social networks to solve these challenges. To address consistency matching problem, we propose a greedy algorithm based on a user trade‐off metric. For optimization tradeoff problem, a closeness edge‐editing technology is considered, which can change the private information slightly. Finally, we evaluate our scheme on real‐world datasets, the experimental results show that theγ‐Strawman scheme is efficient. Copyright © 2017 John Wiley & Sons, Ltd.

Cloud storage services are widely deployed and employed in recent years. A number of data checking techniques have been proposed for secure cloud storage services. These state-of-the-art schemes only focus on some aspects, such as data integrity, users' ownership, and data resiliency, but the overall safety of cloud storage services is not discussed sufficiently. Considering cloud storage requirements as a whole, in this paper, we propose a model of message-locked proof of ownership and retrievability with remote repairing, which provides data confidentiality, secure cross-user deduplication at the client-side, file retrievability, ownership privacy-preserving, random block accessing, and remote repairing simultaneously. In addition, we also propose a concrete construction and prove its security in the random oracle model. The experimental results show that our construction is efficient in practice. Copyright © 2016 John Wiley & Sons, Ltd.

Location service is one of the primary services in smart automated systems of Internet of Things (IoT). For various location-based services, accurate localization has become a key issue. Recently, research on IoT localization systems for smart buildings has been attracting increasing attention. In this paper, we propose a novel localization approach that utilizes the neighbor relative received signal strength to build the fingerprint database and adopts a Markov-chain prediction model to assist positioning. The approach is called the novel localization method (LNM) in short. In the proposed LNM scheme, the history data of the pedestrian's locations are analyzed to further lower the unpredictable signal fluctuations in a smart building environment, meanwhile enabling calibration-free positioning for various devices. The performance evaluation conducted in a realistic environment shows that the presented method demonstrates superior localization performance compared with well-known existing schemes, especially when the problems of device heterogeneity and WiFi signals fluctuation exist.

The upsurge of cloud video recording (CVR) has gained increasing attention from the general public and entrepreneurs. With live video records archived in the cloud, the CVR paradigm enables various smart services by keeping track of activities in the monitored region from anywhere at any time. However, the limited upstream bandwidth affects the quality of surveillance when multiple distributed cameras share the same upstream link. To solve the problem, this paper proposes an efficient upstream bandwidth multiplexing algorithm to intelligently allocate upstream bandwidth for each live video stream while maximizing the overall utility from the perspective of a CVR user. Specifically, we formulate the upstream bandwidth multiplexing problem as a constrained stochastic optimization problem, and apply the technique of hierarchical approximation to solve it efficiently. Our algorithm can be extended to take the priority of video streams into account and allocate more upstream bandwidth to video streams with higher priorities. We explicitly prove the approximation ratio of the proposed algorithm. In addition, we also conduct extensive trace-driven simulations to verify the effectiveness of our algorithm. The simulation results show that our algorithm improves the overall CVR user utility by over 20% compared with other alternatives, and the average utility per bandwidth unit is guaranteed to be stable even when the number of video streams increases.

In this paper, we address the problem of how to make the wireless service provider (WSP) earn profits in a wireless video broadcast network with consideration of advertisement insertion. At the beginning, this study examines the profit components by analyzing traffic provision and advertisement insertion. This study considers using two components for profit maximization-one is the function for allocating video rates, and the other is the function for inserting advertisement duration. The maximum achievable profit depends on joint optimization of optimal video-rate vectors and advertisement-duration vectors, which are usually computationally intensive. To resolve such a complexity problem, this work also proposes an effective algorithm for joint optimization. First, the overall profit is formulated as the solution of four local optimization problems through horizontal and vertical decomposition. Second, a theoretic polymatroidal framework is introduced in our work for optimization as this framework is proved effective in profit maximization of multiuser systems. Third, this study shows that the overall profit can be maximized by finding the optimal profit points on the boundary of the rate and duration regions. As a result, the optimum points and the total profit can be obtained through a hierarchical greedy algorithm. Experimental results demonstrate that the proposed method is capable of making maximum profits for WSPs in a wide range of broadcasting rates.

Recognizing and retrieving multimedia content with movie/TV series actors, especially querying actor-specific videos in large scale video datasets, has attracted much attention in both the video processing and computer vision research field. However, many existing methods have low efficiency both in training and testing processes and also a less than satisfactory performance. Considering these challenges, in this paper, we propose an efficient cloud-based actor identification approach with batch-orthogonal local-sensitive hashing (BOLSH) and multi-task joint sparse representation classification. Our approach is featured by the following: 1) videos from movie/TV series are segmented into shots with the cloud-based shot boundary detection; 2) while faces in each shot are detected and tracked, the cloud-based BOLSH is then implemented on these faces for feature description; 3) the sparse representation is then adopted for actor identification in each shot; and 4) finally, a simple application, actor-specific shots retrieval is realized to verify our approach. We conduct extensive experiments and empirical evaluations on a large scale dataset, to demonstrate the satisfying performance of our approach considering both accuracy and efficiency.

In the era of mobile Internet, mobile game apps (i.e., applications) enable users to play games on mobile devices anywhere at any time. Such a change has brought a dramatic revolution to the traditional gaming industry. In this paper, we aim at having a comprehensive understanding of the ecosystem of mobile game apps. To this purpose, we conduct a large-scale measurement study over all game apps hosted by four leading app stores in China, which cover both Android and iOS platforms. We collect information of over 75000 mobile game apps in a period of three months (October 2014-January 2015). With obtained datasets, we study the scale, evolution, and overlap of game apps in different app stores from a macroscopic level. We find that none of major app stores can provide a complete set of all game apps. We also investigate download patterns of mobile game apps and the impacts brought by user comments and ratings. We observe clear Pareto effect and power-law effect for game app downloads, and there is no strong positive correlation between app score and the number of its downloads. Last, we characterize the features of popular and unpopular game apps and confirm the negative impacts of embedded ads and paid items. We believe our measurement results can provide useful insights and advice for users, developers, and app store operators.

The four papers in this special section aim to present high-quality contributions and innovations in this interdisciplinary area of mobile big data technologies, systems, and services, especially mobile big data management and innovative applications.

User generated content (UGC)-based applications are gaining lots of popularity among the community of mobile internet users. They are populating video platforms and are shared through different online social services, giving rise to the so-called mobile social media applications. These applications are characterized by communication sessions that frequently and dynamically update content, shared with a potential number of mobile users, sharing the same location or being dispersed over a wide geographical area. Since most of UGC content of mobile social media applications are exchanged through mobile devices, it is expected that along with online social applications, these content will cause severe congestion to mobile networks, impacting both their core and radio access networks. In this paper, we address the challenges introduced by these applications devising a complete framework that 1) identifies such applications/sessions and 2) initiates multicast-based delivery (or offload through WiFi) of the relevant content. The proposed framework leverages the network function virtualization (NFV) paradigm to dynamically integrate its functionalities to the operators' service function chaining (SFC) process, allowing fast deployment and lowering both capital and operational expenditures (CAPEX and OPEX) of the mobile operators. The performance of the proposed framework is evaluated through mathematical analysis and computer simulations, taking Twitter-like social applications as an example.

Abstract With the widespread deployment of cloud services, data center networks are developing toward large‐scale, multi‐path networks. Conventional switching‐oriented data center network meets difficulties in terms of scalability and flexibility to support increasing bandwidth requirements for cloud services. To solve this problem, a simple and scalable architecture, MatrixDCN, is proposed in this paper. MatrixDCN is an approximate non‐blocking network, in which switches and servers are arranged in rows and columns that compose a matrix structure. A MatrixDCN network can accommodate up to hundreds of thousands of servers without bandwidth bottlenecks. Furthermore, the physical topology of a MatrixDCN network can be designed consistently with its logic topology, which helps to reduce the complexity of the management and maintenance of a data center. An efficient routing algorithm, named fault‐avoidance routing (FAR), is well designed for MatrixDCN to fully leverage the regularity in the topology. FAR builds two routing tables for a router. A BRT is built based on local topology, and a novel negative routing table (NRT) is increasingly built based on learned partial network failures, which really avoids the problem of network convergence and further shortens the calculating time of routing tables. FAR also greatly reduces the size of routing tables by introducing NRTs at routers. Theoretical analysis and simulations show that MatrixDCN has advantages on the scalability of topology, network throughput, and the performance of FAR. Copyright © 2015 John Wiley & Sons, Ltd.

Vehicular ad hoc networks (VANETs) which are deployed along roads make traffic systems safer and efficient. Existing theoretical results on capacity scaling laws provide insights and guidance for the design and deployment of VANETs. In this paper, we propose a novel fundamental framework RVWNM (Real Vehicular Wireless Network Model), which enables a more realistic capacity analysis in VANETs. We first introduce a Euclidean planar graph which can be constructed from any real map of urban area, and represents the practical geometry structure of the urban area. Then, an interference relationship graph is abstracted from the Euclidean planar graph which considers the transmission interference relations among the nodes in the network. Finally, we analyze theoretically the interference relationships in the interference relationship graph. As far as we know, we are the first to use a practical geometry structure to calculate the asymptotic capacity of VANETs. To verify the feasibility of RVWNM, we calculate the asymptotic capacity of urban area VANETs with the consideration of social- proximity based mobility of vehicles.

Along with an ever-growing demand for rich video applications by a rapidly increasing population of mobile users, it is becoming difficult for the Internet backbone to cope with a constantly increasing mobile traffic. Though multi-source mobile streaming (MS2) was proposed to solve the bottleneck issue of the Internet backbone considering simultaneous multiple low streaming rate transmissions to mobile users, it does not consider redundant transmissions of popular contents. Recently, Content Centric Networking (CCN) is proposed as a content name-oriented approach to disseminate content to edge gateways/routers. In CCN, if the content is popular, the previously queried content can be reused for multiple times to save bandwidth capacity, reduce overall energy consumption, and improve users' Quality of Experience (QoE). Inheriting all advantages of CCN, a novel architecture "MM3C", which integrates CCN with MS2, is proposed as a better solution to the problem. Using OPNET, the performance of MM3C is evaluated. Compared to MS2 under the same network configuration, the simulation results show that MM3C exhibits less bottleneck links, shorter round trip times, and better performance in terms of traffic offloading.

Dynamic event detection by using participatory sensing paradigms has received growing interests in recent years, where detection tasks are assigned to smart device users who can potentially collect needed sensory data from the equipped sensors. These data can be utilized to detect interested events like noise, air pollution, or even earthquake. Since most existing solutions focus on centralized detection approaches that, however, usually cause heavy communication overhead, it is strongly desired to design distributed solutions to reduce energy consumption while achieving a high level of detection accuracy. In this paper, we first present a novel Minimum Cut based centralized detection algorithm as the performance benchmark, and then introduce a novel distributed, energy-efficient solution, where an optimization problem is formulated and an optimal solution is derived. Simulations based on a real-trace driven data set in Beijing demonstrate the effectiveness of our proposed algorithms.

Performance of multihop cooperative sensor networks depends on relaying candidate selection, optimal relay assignment, and cooperative communication. In this paper, we first propose a novel relaying candidate selection scheme (KCN-selection) to choose k-cooperative nodes (KCN) at each hop based on geographic information, while the certain number of k is initially determined based on an on-demand end-to-end (ETE) reliability in the presence of unreliable communication links. However, the pre-assigned KCN cannot ensure an optimal performance due to wireless channel dynamics. To prolong the lifetime of wireless sensor network (WSN), we schedule some part of KCN to sleep while the on-demand ETE reliability still can be guaranteed with wireless channel variations. A probabilistic ETE reliability model is built to compute optimal duty cycle for KCN in an online manner. Furthermore, a KCN based optimal relay assignment and cooperative data delivery (KCN-delivery) scheme is presented, which can provide fully stateless, energy-efficient sensor-to-sink data delivery at a low communication overhead without the help of prior neighborhood knowledge. Simulation results show that our scheme significantly outperforms existing protocols in wireless sensor networks with highly dynamic wireless channel.

In order to improve the accuracy and efficiency of emotion recognition, we design a novel system called Learning through Interactive Video and Emotion-aware System (LIVES). LIVES includes data collection, emotion recognition, and result validation, as well as emotion feedback. We adopt transfer learning to label and validate moods in LIVES, while the emotion can be classified into six types of mood in a reasonable accuracy. Through transfer learning, the time-consuming and labor-intensive processing cost on data collection and labeling can also be greatly reduced. In our prototype system, LIVES is used to enhance an emotion-aware robot's intelligence provided by cloud. LIVES-based emotion recognition is executed in the remote cloud while corresponding result is sent to the robot for emotion feedback. The experimental results demonstrate LIVES significantly improves the accuracy and effective of emotion classification.

Multipath routing in wireless multimedia sensor network makes it possible to transfer data simultaneously so as to reduce delay and congestion and it is worth researching. However, the current multipath routing strategy may cause problem that the node energy near sink becomes obviously higher than other nodes which makes the network invalid and dead. It also has serious impact on the performance of wireless multimedia sensor network (WMSN). In this paper, we propose a pair-wise directional geographical routing (PWDGR) strategy to solve the energy bottleneck problem. First, the source node can send the data to the pair-wise node around the sink node in accordance with certain algorithm and then it will send the data to the sink node. These pair-wise nodes are equally selected in 360° scope around sink according to a certain algorithm. Therefore, it can effectively relieve the serious energy burden around Sink and also make a balance between energy consumption and end-to-end delay. Theoretical analysis and a lot of simulation experiments on PWDGR have been done and the results indicate that PWDGR is superior to the proposed strategies of the similar strategies both in the view of the theory and the results of those simulation experiments. With respect to the strategies of the same kind, PWDGR is able to prolong 70% network life. The delay time is also measured and it is only increased by 8.1% compared with the similar strategies.

Cloud gaming has become a new trend for gamers to access high-end video games. By rendering games in the remote cloud and streaming video scenes to the users, games can be played anywhere, anytime, on any device (e.g., smartphones, tablets, or personal computers). In this paper, we address the problem of achieving cost-effective adaptive cloud gaming in geo-distributed data centers from the perspective of cloud gaming service providers (CGSPs). Unlike previous work, we consider a cloud gaming system supported with the adaptive streaming technology. Our purpose is to minimize the overall service cost for CGSPs, by adaptively adjusting the selection of data centers, virtual machine allocation and video bitrate configuration for each user. Meanwhile, we also need to ensure good-enough quality of experience (QoE) for gamers. To this objective, we formulate the problem into a constrained stochastic optimization problem, and apply the Lyapunov optimization theory to drive the corresponding online strategy with provable upper bounds. Due to the diverse QoE requirements of video games, we also take the difference among game genres into account during the algorithm design. Finally, we conduct extensive trace-driven simulations to evaluate the effectiveness of our algorithm and our results show that our proposed algorithm can achieve significant gain over other alternative approaches.

The Internet of Things (IoT) opens up tremendous opportunities to location-based industrial applications that leverage both Internet-resident resources and phones' processing power and sensors to provide location information. Location-based service is one of the vital applications in commercial, economic, and public domains. In this paper, we propose a novel localization scheme called NextMe, which is based on cellular phone traces. We find that the mobile call patterns are strongly correlated with the co-locate patterns. We extract such correlation as social interplay from cellular calls, and use it for location prediction from temporal and spatial perspectives. NextMe consists of data preprocessing, call pattern recognition, and a hybrid predictor. To design the call pattern recognition module, we introduce the notions of critical calls and corresponding patterns. In addition, NextMe does not require that the cell tower addresses should be bounded with concrete coordinates, e.g., global positioning system (GPS) coordinates. We validate NextMe across MIT Reality Mining Dataset, involving 500 000 h of continuous behavior information and 112 508 cellular calls. Experimental results show that NextMe achieves fine-grained prediction accuracy at cell tower level in the forthcoming 1-6 h with 12% accuracy enhancement averagely from cellular calls.

Cooperative spatial multiplexing (CSM) system has played an important role in wireless networks by offering a substantial improvement in multiplexing gain compared with its cooperative diversity counterpart. However, there is a limited number of research works that consider the performance of CSM systems. As such, in this paper, we have derived exact performance of CSM with amplify-and-forward and decode-and-forward relays in terms of outage capacity and ergodic capacity. We have shown that CSM systems yield a unity diversity order regardless of the number of antennas at the destination and the number of relays in the networks, which is the direct result of diversity and multiplexing gain trade-off. Our analytical expressions are corroborated by Monte-Carlo simulations

Abstract In sparse mobile wireless networks, normally, the mobile nodes are carried by people, and the moving activity of nodes always happens in a specific area, which corresponds to some specific community. Between the isolated communities, there is no stable communication link. Therefore, it is difficult to ensure the effective packet transmission among communities, which leads to the higher packet delivery delay and lower successful delivery ratio. Recently, an additional ferry node was introduced to forward packets between the isolated communities. However, most of the existing algorithms are working on how to control the trajectory of only one ferry work in the network. In this paper, we consider multiple ferries working in the network scenario and put our main focus on the optimal packet selection strategy, under the condition of mutual influence between the ferries and the buffer limitation. We introduce a non‐cooperative Bayesian game to achieve the optimal packet selection strategy. By maximizing the individual income of a ferry, we optimize the network performance on packet delivery delay and successful delivery ratio. Simulation results show that our proposed packet selection strategy improves the network performance on packet delivery delay and successful delivery ratio. Copyright © 2013 John Wiley & Sons, Ltd.

Online games have been played mainly in desktop computers over wired networks because of high speed and intensive computation requirements. The advances in mobile devices and ever increasing wireless link bandwidth motivate us to study whether players can enjoy online gaming over broadband wireless networks such as mobile Worldwide Inter-operability for Microwave Access WiMAX. In this paper, we carry out comprehensive measurements of the World of Warcraft WoW over the mobile WiMAX in Seoul, Korea, and analyze the network performance focusing on two aspects: 1 network layer dynamics such as round trip time, jitter, and packet loss and 2 WiMAX link layer statistics such as the radio signal strength, handovers, and piggyback mechanism. From the empirical data, we set up performance models and evaluate the performance of WoW over WiMAX. We also discuss how to improve the service quality of online gaming over WiMAX.Copyright © 2013 John Wiley & Sons, Ltd.

In Orthogonal Frequency Division Multiplexing (OFDM)-based mobile networks (e.g., Long Term Evolution Advanced), Downlink Control Information (DCI) in a Physical Downlink Control Channel (PDCCH) plays a unique role in carrying control signaling and scheduling information, which enables the flexibility and diversity of radio resource utilization. Due to system configuration limitations, power dimension is the only potential to enhance DCI reliability. Based on this motivation, we apply the synergy concept to power dimension: called Power Synergy, which can deal with negative effects caused by Cell-specific Reference Signal (CRS) power boosting, and also allow flexibly power lending between OFDM symbols in the physical control region. Under the constraints of the Block Error Rate (BLER) threshold 102given for PDCCHs and the CRS full-cell coverage requirement, performance tests reveal there are significant profits (for example, 10-dB gain available for enhancing DCI reliability in the worst case) from the power headroom in the physical control region. This valuable gain is helpful to accommodate emerging mobile broadband services (e.g., mobile health) in LTE/LTE-A networks.

In contrary to conventional gaming-on-demand solution, cognitive cloud gaming platform facilitates gaming component migration from the cloud server to the players' terminal, a novel flexible solution to provide Gaming as a Service. In this work, we model the component-based game and investigate the capacity of intelligent resource management for different optimization targets, including cloud resource minimization and throughput-oriented optimization. Experimental results show that, with the cognitive resource management, cloud system is adaptive to various service requirements, such as increasing the quantity of supported devices and reducing the network throughput of user terminals, while satisfying players' quality of experience.

The Follow-Me Cloud (FMC) concept enables service mobility across federated data centers (DCs). Following the mobility of a mobile user, the service located in a given DC is migrated each time an optimal DC is detected. The detailed criterion for optimality is defined by operator policy, but it may be typically derived from geographical proximity or load. Service migration may be an expensive operation given the incurred cost in terms of signaling messages and data transferred between DCs. Decision on service migration defines therefore a tradeoff between cost and user perceived quality. In this paper, we address this tradeoff by modeling the service migration procedure using a Markov Decision Process (MDP). The aim is to formulate a decision policy that determines whether to migrate a service or not when the concerned User Equipment (UE) is at a certain distance from the source DC. We numerically formulate the decision policies and compare the proposed approach against the baseline counterpart.

The ever increasing traffic demand becomes a serious concern of mobile network operators. To solve this traffic explosion problem, there have been many efforts to offload the traffic from cellular links to direct communications among users. In this paper, we propose the framework of Traffic Offloading assisted by Social network services (SNS) via opportunistic Sharing in mobile social networks, TOSS, to offload SNS-based cellular traffic by user-to-user sharing. First we select a subset of users who are to receive the same content as initial seeds depending on their content spreading impacts in online SNSs and their mobility patterns in offline mobile social networks (MSNs). Then users share the content via opportunistic local connectivity (e.g., Bluetooth, Wi-Fi Direct, Device-to-device in LTE) with each other. The observation of SNS user activities reveals that individual users have distinct access patterns, which allows TOSS to exploit the user-dependent access delay between the content generation time and each user's access time for traffic offloading purposes. We model and analyze the traffic offloading and content spreading among users by taking into account various options in linking SNS and MSN trace data. The trace-driven evaluation demonstrates that TOSS can reduce up to 86.5% of the cellular traffic while satisfying the access delay requirements of all users.

Content Centric Networking (CCN) is a content name-oriented approach to disseminate content to edge gateways/routers. In CCN, a content is cached at routers for a certain time. When the associated deadline is reached, the content is removed to cope with the limited size of content storage. If the content is popular, the previously queried content can be reused for multiple times to save bandwidth capacity. It is, therefore, critical to design an efficient replacement policy to keep popular content as long as possible. Recently, a novel caching strategy, named Most Popular Content (MPC), was proposed for CCN. It considers the high skewness of content popularity and outperforms existing default caching approaches in CCN such as Least Recently Used (LRU) and Least Frequency Used (LFU). However, MPC has some undesirable features, such as slow convergence of hitting rate and unstable hitting rate performance for various cache sizes. In this paper, a new caching policy, dubbed Fine-Grained Popularity-based Caching (FGPC), is proposed to overcome the above-mentioned weak points. Compared to MPC, FGPC always caches coming content when storage is available. Otherwise, it keeps only most popular content. FGPC achieves higher hitting rate and faster convergence speed than MPC. Based on FGPC, we further propose a Dynamic-FGPC (D-FGPC) approach that regularly adjusts the content popularity threshold. D-FGPC exhibits more stability in the hitting rate performance in comparison to FGPC and that is for various cache sizes and content sizes. The performance of both FGPC and D-FGPC caching policies are evaluated using OPNET Modeler. The obtained simulation results show that FGPC and D-FGPC outperform LRU, LFU, and MPC.

With the development of e-commerce, a growing number of people prefer to purchase medicine online for the sake of convenience. However, it is a serious issue to purchase medicine blindly without necessary medication guidance. In this paper, we propose a novel cloud-based medicine recommendation, which can recommend users with top-N related medicines according to symptoms. Firstly, we cluster the drugs into several groups according to the functional description information, and design a basic personalized medicine recommendation based on user collaborative filtering. Then, considering the shortcomings of collaborative filtering algorithm, such as computing expensive, cold start, and data sparsity, we propose a cloud-based approach for enriching end-user Quality of Experience (QoE) of medicine recommendation, by modeling and representing the relationship of the user, symptom and medicine via tensor decomposition. Finally, the proposed approach is evaluated with experimental study based on a real dataset crawled from Internet.

Recently, cardiovascular disease (CVD) has become one of the leading death causes worldwide, and it contributes to 41% of all deaths each year in China. This disease incurs a cost of more than 400 billion US dollars in China on the healthcare expenditures and lost productivity during the past ten years. It has been shown that the CVD can be effectively prevented by an interdisciplinary approach that leverages the technology development in both IT and electrocardiogram (ECG) fields. In this paper, we present WE-CARE , an intelligent telecardiology system using mobile 7-lead ECG devices. Because of its improved mobility result from wearable and mobile ECG devices, the WE-CARE system has a wider variety of applications than existing resting ECG systems that reside in hospitals. Meanwhile, it meets the requirement of dynamic ECG systems for mobile users in terms of the detection accuracy and latency. We carried out clinical trials by deploying the WE-CARE systems at Peking University Hospital. The clinical results clearly showed that our solution achieves a high detection rate of over 95% against common types of anomalies in ECG, while it only incurs a small detection latency around one second, both of which meet the criteria of real-time medical diagnosis. As demonstrated by the clinical results, the WE-CARE system is a useful and efficient mHealth (mobile health) tool for the cardiovascular disease diagnosis and treatment in medical platforms.

As cloud computing and wireless body sensor network technologies become gradually developed, ubiquitous healthcare services prevent accidents instantly and effectively, as well as provides relevant information to reduce related processing time and cost. This study proposes a co-processing intermediary framework integrated cloud and wireless body sensor networks, which is mainly applied to fall detection and 3-D motion reconstruction. In this study, the main focuses includes distributed computing and resource allocation of processing sensing data over the computing architecture, network conditions and performance evaluation. Through this framework, the transmissions and computing time of sensing data are reduced to enhance overall performance for the services of fall events detection and 3-D motion reconstruction.

With the widely deployed cloud services, data center networks are evolving toward large-scale and multi-path networks, which cannot be supported by conventional routing methods, such as OSPF and RIP. To alleviate this issue, some new routing methods, such as PortLand and BSR, are proposed for data center networks. However, these routing methods are typically designed for a specific network architecture, and thus lacking adaptability while complex in fault-tolerance. To address this issue, this paper proposes a generic routing method, named fault-avoidance routing (FAR), for data center networks that have regular topologies. FAR simplifies route learning by leveraging the regularity in a topology. FAR also greatly reduces the size of routing tables by introducing a novel negative routing table (NRT) at routers. The operations of FAR is illustrated by an example Fat-tree network and the performance of FAR is analyzed in detail. The advantages of FAR are verified through extensive OPNET simulations.

Mobile cloud gaming provides a whole new service model for the video game industry to overcome the intrinsic restrictions of mobile devices and piracy issues. However, the diversity of end-user devices and frequent changes in network quality of service and cloud responses result in unstable Quality of Experience (QoE) for game players. A cognitive cloud gaming platform, which could overcome the above problem by learning about the game player's environment and adapting the cloud gaming service accordingly, does not currently exist. To fill this void, we design and implement a component-based gaming platform that supports click-and-play, intelligent resource allocation and partial offline execution, to provide cognitive capabilities across the cloud gaming system. Extensive experiments have been performed to show that intelligent partitioning leads to better system performance, such as overall latency.

Understanding and modelling the users' perceptual quality of a video are the key steps towards improving multimedia service provision. In this paper, we take an analytical approach to study the joint impact of spatial and temporal resolution on the perceptual video quality. First, we map the subjective quality data as an evaluation function in terms of the spatial resolution and frame rate, which reflect the major features of web video quality. Second, we use ε-Support Vector Regression (ε-SVR) with Radial Basis Function (RBF) kernel to give a more accurate hybrid temporal-spatial quality evaluation model so as to predict the perceptual video quality. The comprehensive subjective quality experiments were carried out to construct and validate this model. The experimental results demonstrated the effectiveness of the proposed model. Besides, the quality model can be easily deployed in a practical multimedia delivery system.

In Long Term Evolution-Advanced (LTE-A) networks, the quasi-static configuration of Control Channel Element (CCE) creates multiple challenges to real-time mobile health (mHealth) applications. To handle these challenges, we propose a novel solution, Service-oriented Self-adaptive CCE (S2-CCE) configuration mechanism. This proposal can dynamically configure the just-enough number of CCEs for mHealth users according to their scenarios, which can avoid the overutilization of the limited CCE resources. Furthermore, this self-adaptive CCE configuration is also self-aware to service quality from an mHealth user, which can solve the time-sensitive concern in mHealth applications, for example, emergency call and Consultation Video for the point of care. Consequently, we conceive an algorithm to implement the S2-CCE mechanism, in which the initial CCE configuration is based on the Channel Quality Indicator (CQI) reported by an mHealth user from a real deployment, and then this initialized CCE configuration can be intelligently adjusted according to QoS (Quality of Service) requirements from the mHealth user by introducing a concept of Service-Aware Degree (SAD). Our LTE-A system-level simulation experiments demonstrate that the S2-CCE can reduce average delay remarkably for mHealth applications (including HL7, DICOM mHealth users achieving 50% lower delay in contrast with non-service-aware method when there are 50 mHealth users in the cell). And it achieves high user satisfaction (almost 100%) in multi-user scenarios given a milder relaxation to user fairness.

Wireless Body Area Network (WBAN) includes a set of body sensor nodes which are placed around human body, collecting data while sending them to medical center. In order to deliver the body signal to remote terminals in timely fashion, an extended communication architecture dubbed “beyond-BAN communication” was proposed. However, existing architectures are not suitable for the scenarios with high mobility of both patients and physicians due to the fluctuation of wireless links. Furthermore, when the amount of healthcare content is large, the quality of delivery is hard to be guaranteed. To address these challenging issues, we propose a novel network architecture, which integrates WBAN with the Long Term Evolution (LTE) networking and Named Data Networking (NDN). The integration with LTE is to enlarge the radio coverage and guarantee the quality of wireless transmissions, while the integration with NDN is to leverage edge router caching technique to enhance the capacity of the WBAN coordinator, and to avoid the packets loss by adapting to dynamic wireless link conditions with the adaptive streaming technique. The experimental results conducted by OPNET Modeler prove that our solution improves the Quality of Service (QoS) performance of WBAN transmission significantly.

In developing countries, people's living pressure is increasing with the society's development by inefficient economic growth mode. Recently, the number of people who suffer from sudden cardiac death is progressively increasing, and cardiovascular disease (CVD) has become one great killer which threats the life and health of people. However, at present, we are confronted with one problem: when a patient has chest distress or chest pain, etc., he/she hurries to the hospital to go through electrocardiograph (ECG) examination but the abnormal ECG signal disappears. Therefore, the opportunity to timely capture the ECG status of a patient and make an accurate judgment is lost. Thus, extensive efforts have been made to design various systems for patient monitoring at anytime and anywhere, in order to have real-time records and analysis on vital signal of patents, so as to provide early detection before the occurrence of adverse effect. However, the mobility of the patient is limited in most existing healthcare systems. While sporting is beneficial to improve patient's health, designing a comfortable and durable healthcare system for facilitating patient's movement is a critical issue. This paper presents a novel comfortable and durable portable ECG monitoring system to have real-time monitoring and analysis on a moving user. In the meantime, its special low power and on-demand data collection design alleviates the problem that the current wearable ECG monitoring equipment could not be used for a long time due to the constraint of its battery life.

Mobile cloud computing, promising to extend the capabilities of resource-constrained mobile devices, is emerging as a new computing paradigm which has fostered a wide range of exciting applications. In this new paradigm, efficient data transmission between the cloud and mobile devices becomes essential. This, however, is highly unreliable and unpredictable due to several uncontrollable factors, particularly the instability and intermittency of wireless connections, fluctuation of communication bandwidth, and user mobility. Consequently, this puts a heavy burden on the energy consumption of mobile devices. Confirmed by our experiments, significantly more energy is consumed during “bad” connectivity. Inspired by the feasibility to schedule data transmissions for prefetching-friendly or delay-tolerant applications, in this paper, we present eTime, a novel Energy-efficient data Transmission strategy between cloud and Mobile dEvices, based on Lyapunov optimization. It aggressively and adaptively seizes the timing of good connectivity to prefetch frequently used data while deferring delay-tolerant data in bad connectivity. To cope with the randomness and unpredictability of wireless connectivity, eTime only relies on the current status information to make a global energy-delay tradeoff decision. Our evaluations from both trace-driven simulation and realworld implementation show that eTime can be applied to various popular applications while achieving 20%-35% energy saving.

In pervasive computing environment, due to the mobility feature of mobile terminals, the mobile service needs to dynamically adapt execution behavior to the changing computing environment as mobile user moves. However, previous researches mainly focused on deploying a service adaption module on mobile terminals or local central server to support the adaptive execution of mobile services, which brings huge overhead to mobile terminals or can hardly meet user's personalized requirements. Therefore, we propose a cloud based framework, called CAMSPF, which includes three parts: RMC (resource management cloud), AMSPC (adaptive mobile service provision cloud), and MSM (mobile service middleware). The CAMSPF deploys the service resources in RMC for realizing efficient resource management and provision, and constructs a PMSAA (private mobile service adaption agent) for each mobile user in AMSPC in order to efficiently support personalized adaptive execution of mobile service. In addition, the MCM is a lightweight software installed on mobile terminals by which CAMSPF can collect user's realtime context and monitor service request from mobile user. Our prototype implementation of CAMSPF verifies that the adaptive execution of mobile services can be performed more efficiently than other traditional approaches, with lower energy consumption on mobile terminals.

Welcome to this special issue of the Computer Journal. This special issue is devoted to the topics of the latest research and development on green mobile networking and communications. Nowadays, the explosive development of information and communication technology has significantly enlarged both the energy demands and CO2 emissions, and consequently makes the energy crisis and global warming problems worse. To meet the requirements of low-carbon economic development, mobile networking and communications techniques should be green and energy-aware, while maintaining an acceptable quality of service for various applications. This special issue explores the recent research contributions in designing, building and deploying green networks and communications. The selected papers are classified into three categories: green mobile networking, green cloud and data center networking and green wireless communications. A comprehensive overview of the selected papers is given below.

In cognitive radio cooperative communication (CR-CC) systems, the achievable data rate can be improved by increasing the transmission power. However, the increase in power consumption may cause the interference with primary users and reduce the network lifetime. Most previous work on CR-CC did not take into account the tradeoff between the achievable data rate and network lifetime. To fill this gap, this paper proposes an energy-efficient joint relay selection and power allocation scheme in which the state of a relay is characterized by the channel condition of all related links and its residual energy. The CR-CC system is formulated as a multi-armed restless bandit problem where the optimal policy is decided in a distributed way. The solution to the restless bandit formulation is obtained through a first-order relaxation method and a primal-dual priority-index heuristic, which can reduce dramatically the on-line computation and implementation complexity. According to the obtained index, each relay can determine whether to provide relaying or not and also can control the corresponding transmission power. Extensive simulation experiments are conducted to investigate the effectiveness of the proposed scheme. The results demonstrate that the power consumption is reduced significantly and the network lifetime is increased more than 40%.

Recent advances in the fields of wireless technology have exhibited a strong potential and tendency on improving human life by means of ubiquitous communications devices that enable smart, distributed services. In fact, traditional human to human (H2H) communications are gradually falling behind the scale of necessity. Consequently, machine to machine (M2M) communications have surpassed H2H, thus drawing significant interest from industry and the research community recently. This paper first presents a four-layer architecture for internet of things (IoT). Based on this architecture, we employ the second generation RFID technology to propose a novel intelligent system for M2M communications.

With the increase in commercial electronic equipment and its complicated control interfaces, how to design an effective and user-friendly control interface has become a topic for many researchers. This research introduces two-directional communication of an interactive graphical user interface on a universal remote control (URC). It is different from current URCs where users must often spend huge amounts of time setting the command codes and encoding each device. With the increase in the number of appliances that the controller needs to manage and the complicated and numerous control buttons, using such controllers often causes difficulties for users. This research employs a cross-platform with integration theories, so when a user wants to connect an appliance, both the appliance end and the controller end will build a two-directional connection through pairing over Radio Frequency for Consumer Electronics (RF4CE). After connection, the system will automatically set the communication protocol between the controller and the device. The appliance will automatically transmit its current state and service in the form of bundles to the controller, then the controller will project it onto an LCD screen. The controller can also show the number of appliances connected to the current position of the user, allowing the user to use one controller to control all home appliances with ease, achieving a simplified and instinctive control interface to build the integrated control environment for commercial appliances.

While demands on video traffic over mobile networks have been souring, the wireless link capacity cannot keep up with the traffic demand. The gap between the traffic demand and the link capacity, along with time-varying link conditions, results in poor service quality of video streaming over mobile networks such as long buffering time and intermittent disruptions. Leveraging the cloud computing technology, we propose a new mobile video streaming framework, dubbed AMES-Cloud, which has two main parts: adaptive mobile video streaming (AMoV) and efficient social video sharing (ESoV). AMoV and ESoV construct a private agent to provide video streaming services efficiently for each mobile user. For a given user, AMoV lets her private agent adaptively adjust her streaming flow with a scalable video coding technique based on the feedback of link quality. Likewise, ESoV monitors the social network interactions among mobile users, and their private agents try to prefetch video content in advance. We implement a prototype of the AMES-Cloud framework to demonstrate its performance. It is shown that the private agents in the clouds can effectively provide the adaptive streaming, and perform video sharing (i.e., prefetching) based on the social network analysis.

Traditional α -fairness resource allocation in wireless multimedia communications assumes that the quality of experience (QoE) model (or utility function) of each user is available to the base station (BS), which may not be valid in many practical cases. In this paper, we consider a blind scenario where the BS has no knowledge of the underlying QoE model. Generally, this consideration raises two fundamental questions. Is it possible to set the fairness parameter α in a precisely mathematical specific α -fairness resource allocation schememanner? If so, is it possible to implement a specific α -fairness resource allocation scheme online? In this work, we will give positive answers to both questions. First, we characterize the tradeoff between the performance and fairness by providing an upper bound of the performance loss resulting from employing α -fairness scheme. Then, we decompose the α-fairness problem into two subproblems that describe the behaviors of the users and BS and design a bidding game for the reconciliation between the two subproblems. We demonstrate that, although all users behave selfishly, the equilibrium point of the game can realize the α-fairness efficiently, and the convergence time is reasonably short. Furthermore, we present numerical simulation results that confirm the validity of the analytical results.

ABSTRACT Relay selection schemes for cooperative communications to achieve full cooperative diversity gains while maintaining spectral and energy efficiency have been extensively studied in a recent research. These schemes select only the best relay from multiple relaying candidates to cooperate with a communication link. In the present paper, we reviewed recently proposed cooperative communication protocols that integrate with relay selection mechanisms. The key design issues for relay selection mechanisms, for example, relaying candidate selection, optimal relay assignment, and cooperative transmission, were identified. We further discussed the challenges of optimal relay assignment in multi‐hop wireless sensor networks and presented the potential applications of cooperative communications with a relay selection in such networks. Future research directions were outlined, for example, the issues of service differentiation and system fairness in cooperative communication systems and the joint use of game theory and adaptive learning techniques in relaying candidate selection and optimal‐relay assignment mechanisms for efficient allocation of network resources. Copyright © 2011 John Wiley & Sons, Ltd.

While demands on video traffic over mobile networks have been souring, the wireless link capacity cannot keep up with the traffic demand. The gap between the traffic demand and the link capacity, along with time-varying link conditions, results in poor service quality of video streaming over mobile networks such as long buffering time and intermittent disruptions. Leveraging the cloud computing technology, we propose a new mobile video streaming framework, dubbed AMVSC, which constructs a private agent at the cloud to provide video streaming services efficiently for each mobile user. For a given user, AMVSC lets her private agent adaptively adjust her streaming flow with a scalable video coding technique based on the feedback of link quality. We implement a prototype of the AMVSC framework to demonstrate its performance. It is shown that the private agents in the clouds can effectively provide the adaptive streaming.

Micro-blog marketing has become a main business model for social networks nowadays. On social networking sites (e.g., Twitter), micro-blog marketing enables the advertisers to put ads to attract customers to buy their products. During this process, a rather key step for the success of advertisers is to conduct marketing researches to discover which micro-blog users are their potential customers who can greatly promote their products to other customers so that the advertising investment can be greatly reduced. This problem is considered as “influence maximization” issue. In this paper and in attempt to discover the influential users in micro-blog marketing, we try to analyze the influences of nodes in a micro-blog network and propose a Community Scale-Sensitive Maxdegree (CSSM) algorithm for maximizing the influences when placing ads. Experimental results on the very hot micro-blog service (i.e., Twitter dataset) demonstrate that our proposed CSSM algorithm significantly outperforms other related node selection strategies, in terms of the influence spread and time complexity.

In intermittently connected mobile Ad Hoc networks, how to guarantee the packet delivery ratio and reduce the transmission delay has become the new challenge for the researchers. Epidemic-theory based routing has shown the better performance in terms of improving packet delivery ratio and reducing the delay, when infinite node buffer and network bandwidth model is assumed. Typically, epidemic routing adopts the 2-hop or multi-hop forwarding mode to deliver a packet. However, these two modes have the intrinsic disadvantage on too much redundant copies or too long delivery delay. In this paper, we introduce a novel H+1 hop forwarding mode that is based on the epidemic theory. Firstly, we utilize the Susceptible-Infective-Recovered (SIR) model of epidemic theory to estimate the amount of relay nodes (epidemic equilibrium) and the delivery delay within the epidemic process. Secondly, we formulate the quantities of relay nodes into a single absorbing Markov Chain model, facilitating the estimation of the expected delay for the packet transmission. Simulation results show that our H+1 hop forwarding mode has the better performance on delay and packet delivery ratio.

Inter-contact time (denoted as TI) between mobile nodes that captures the temporal characteristics of Vehicular Ad Hoc Networks (VANETs) has been intensively studied. Whereas the node spatial distribution is ignored in most existing mobility schemes, which is also worthy of investigation, particularly for real applications. Moreover, the node spatial distribution has a significant influence on the inter-contact time. In this paper, we study the empirical data acquired from taxis in Shanghai city. We find that most taxis distribute on some hot roads which makes the node spatial distribution appear power law. Based on this observation, we propose the concepts of indirect contact and heterogeneous inter-contact time (represented as TH) to reveal how hot roads can change the distribution of inter-contact time. By investigating the empirical data, we show that the THdistribution also appears power law.

In this paper, we consider a power-aware multimedia communications over internet of things (IoT). Specifically, we consider a generic IoT scenario where a multimedia server provides heterogeneous applications without knowing the application's quality of experience (QoE) model and playout period. Our objective aims at dynamically adjusting the power allocation for each application over a uncertain period to maximize the system overall mean opinion score (MOS). Note that the practical QoE model can be observed over time, but the underlying functional relationship between the power and MOS is unknown. The highlight of this paper is to develop a dynamic powering algorithm, in which one learns the satisfaction function and optimizes power-aware user satisfaction with on-line operation. More precisely, the proposed algorithm performance is measured in terms of loss which denotes the MOS loss compared to the optimal one. Numerical simulation results validate the efficiency of the proposed algorithm.

The The ever increasing traffic demand is a serious concern of mobile network operators, and the conventional pull-based (or request-based) communication model may not be able to handle this data explosion problem. To reduce the traffic load on cellular links for disseminating content, we propose to push the content to a subset of subscribers via cellular links, and to allow the subscribers to share the content via opportunistic local connectivity (i.e. Wi-Fi ad-hoc mode). We theoretically model and analyze how the content can be disseminated by both pushing via cellular links and sharing via Wi-Fi links, where handovers are modeled based on the multi-compartment model. We also formulate a mathematical framework to optimize the content dissemination, by which the trade-off between the dissemination delay and the energy cost is explored.

ABSTRACT Network security is an important area in computer science. Although great efforts have already been made regarding security problems, networks are still threatened by all kinds of potential attacks, which may lead to huge damage and loss. Log files are main sources for security analysis. However, log files are not user friendly. It is laborious work to obtain useful information from log files. Compared with log files, visualization systems designed for security purposes provide more perceptive and effective sources for security analysis. Most security visualization systems are based on log files. In this paper, we provide a survey on visualization designs for computer network security. In this survey, we looked into different security visual analytics, and we organized them into five categories. Copyright © 2011 John Wiley & Sons, Ltd.

ABSTRACT Although multi‐hop routing can reduce communication consumption and extend network scale, energy hole is unavoidable to appear because of the relay nodes being overloaded due to take more tasks. In this paper, we formulate the energy equilibrium problem as an optimal corona division, where data fusion and data slice are both considered in data gathering process. For a circular multi‐hop sensor network with uniform node distribution and constant data reporting, we demonstrate that the energy equilibrium of the whole network is unable to be realized no matter whether data fusion and data slice are adopted. However, the maximum energy equilibrium for a given circular area can be achieved only if the area increases in geometric progression from the outer corona to the neighbor inner corona except for the outermost one. Moreover, we use a zone‐based allocation scheme to guarantee energy equilibrium of intra‐corona. The approach for computing the optimal parameters is presented in terms of maximizing network lifetime. Based on the mathematical model, we propose an energy equilibrium routing based on corona structure (EERCS). Simulating results validate that EERCS can effectively achieve energy equilibrium and prolong the lifetime of network. Copyright © 2010 John Wiley & Sons, Ltd.

In sparse mobile social networks, the moving activity of nodes always happen in a specific area, which corresponds to some specific community. How to guarantee the higher packet delivery ratio while reducing forwarding delay in such networks, is a challenging issue and has not been widely investigated yet. Recently, additional super-node was introduced to ferry packets between the isolated areas. However, most existing solutions assume the super-node is always moving according to the fixed trajectory. In this paper, we put some special mobile nodes in the networks, they are called postmen, and their responsibility is to carry packets for normal nodes which belong to specific communities. Our work focus on the optimization of the moving trajectory by considering the minimum transmission delay. We formulate the optimal issue into semi-Markov Decision Process model. The decision process includes two parts: Packets-choosing strategy and trajectory of packet-ferrying-determination strategy. By maximizing the individual reward of a postman, its optimal trajectory will be found. Furthermore, the proposed solution guarantees the packet delivery ratio and delay for isolated communities. Simulation results show that the proposed packet-ferrying solution outperforms two existing ferrying solutions in terms of packet delivery ratio.

In cognitive radio (CR) cooperative networks, the applicable relay scheduling and channel access directly affect the system. However, in practical system, the CR sensor is bound to sensing error. This may lead to low system performance and interfering with primary users. In this paper, we present a learning based centralized scheme for joint relay scheduling and channel access scheme in CR cooperative networks. Specifically, we formulate the joint relay scheduling and channel access problem as a partially observable Markov decision process (POMDP) system, where the most likely channel state is derived by a learning process. The optimal policy is derived by solving the problem. Extensive simulation results show the effectiveness of our proposed scheme.

In traditional delay tolerant networks (DTNs), there exists a potential assumption that the nodes are willing to help others for packet forwarding. However, in the real application scenarios, such as civilian DTNs, selfish behaviors always widely exist. Therefore, the assumption that nodes are cooperative is not realistic in all applications. Currently, most of the existing incentive mechanism focuses on individual selfish behaviors. Few research work is proposed on social selfish behavior in DTNs. In this paper, we stimulate the nodes to cooperate with others by using a virtual bank mechanism. This incentive mechanism can effectively avoid individual selfish behaviors. Meanwhile, we observe that under this individual selfish incentive mechanism, the social distribution is unfair. That means the poverty nodes would appear in the networks, and become the internal threats for the social DTNs. To avoid this, we introduce the Gini coefficient to measure the inequality of the social distribution. Furthermore, by using the taxation strategy, we avoid the internal threats caused by social selfishness. To demonstrate the selfish behavior, we introduce the forwarding protocol which is based on social relations of nodes. We verify the proposed methods using simulation evaluations.

Using body sensor networks (BodyNets) to monitoring the human health is increasingly emerging as a dominant application framework for the evolving sensor network technology. In this paper, we explore how to promote such network work in cold region. Different to the ordinary region, sensors not only need to collect sensory data of human characteristic but also accurately monitor the surround environment of the target human. Specially, the monitoring objectives are affected by the combined effects of many parameters, such as the movement of target human and uncertainty of nature. These parameters are featured in vague and many-to-many association etc, which make the monitoring process in high complexity. We analyze the requirement of Bodynets during the process of monitoring health condition, and design an adaptable system model. Moreover, we use distributed Bayesian estimation to eliminate the inaccuracy of sensory information with the consideration of time and spatial distribution effects on monitoring process. The experiment result show that our design can efficiently guarantee the information accuracy of monitoring objective.

In this paper, we proposed an integrated biometric-based security framework for wireless body area networks, which takes advantage of biometric features shared by body sensors deployed at different positions of a person's body. The data communications among these sensors are secured via the proposed authentication and selective encryption schemes that only require low computational power and less resources (e.g., battery and bandwidth). Specifically, a wavelet-domain Hidden Markov Model (HMM) classification is utilized by considering the non-Gaussian statistics of ECG signals for accurate authentication. In addition, the biometric information such as ECG parameters is selected as the biometric key for the encryption in the framework. Our experimental results demonstrated that the proposed approach can achieve more accurate authentication performance without extra requirements of key distribution and strict time synchronization.

To achieve full cooperative diversity gains while still maintaining spectral and energy efficiency, relay assignment schemes for cooperative communications have been extensively studied in recent research. These schemes select only the best relay from multiple relaying candidates to cooperate with a communication link. In this paper, we formulate the problem of relay assignment as a non-cooperative, mixed strategy, repeated game, where relaying candidates are modeled as rational players. We then propose a Game Theory based Relay Assignment scheme GTRA, in which each player plays against all the other players, and determines whether to cooperate with a communication link on a packet-by-packet basis in a distributed manner. To adapt to dynamic environments, an adaptive learning algorithm is utilized by players to learn optimal strategies of relay assignment, as well as orienting the game to converge to a set of correlated equilibriums. We compare GTRA with BR, a fictitious game based approach. The simulation results show that GTRA outperforms BR in terms of network throughput, especially in environments where the channel fading becomes severe. It is also shown that GTRA can converge to a correlated equilibrium in a short period that enables it to work well in dynamic environments.

Vehicular Delay-Tolerant Network (VDTN) is a new opportunistic network approach where vehicles act as the communication infrastructure, furnishing low-cost asynchronous communications, variable delays, and bandwidth limitations. At the edge of the VDTNs, terminal nodes assume the gateway function with other networks, such as the common TPC/IP. In VDTNs, IP packets (datagrams) are aggregated in large data packets, called bundles. At the edge of the network, incoming nodes aggregate datagrams in VDTN bundles and at the destination edge nodes they are de-aggregated in order to retrieve the original IP packets, forwarding them to the upper layers. This paper proposes several aggregation algorithms for VDTNs and studies their performance evaluation through a laboratory testbed. The results show that combination of time and threshold-based algorithms present the best performance and are more suitable for real deployment.

Recently, vehicular delay-tolerant networks (VDTNs) were proposed as a new network architecture for sparse vehicular networks. VDTN architecture adopts the DTN store-carry-and-forward paradigm. At the edge of the network, terminal nodes provide internetworking on heterogeneous networks. In VDTNs, datagrams are assembled in large data packets, called bundles. At the ingress edge node of VDTNs, bundle aggregation process assemblies incoming IP Packets (datagrams) from the higher layer into bundles. When bundles reach the destination edge node, they are de-aggregated in order to retrieve the original IP packets, forwarding them to the upper layers. This paper proposes several aggregation algorithms based on time or threshold values, and studies their performance evaluation through a laboratory testbed, called VDTN@Lab. The hybrid approach presents the best performance for different types of traffic load.

The sleeping strategy has become popular to reduce power consumption of base stations (BSs) by shutting down underutilized BSs in the management of green cellular networks. In this paper, we propose a novel solution for an energy efficient use of cellular networks, based on traffic load balancing. By modeling the power consumption for BSs connected to uniformly distributed users, the relationship between the optimal number of active (or shut down) BSs and the traffic load is then derived through the power ratio, which is the ratio between dynamic and fixed power part of BS power consumption. Both analytical and simulation results demonstrate that, in order to achieve significant energy savings, less BSs should be turned on at low traffic load while more BSs turned on at high traffic load.

Over the last decade, mobile agent (MA) systems for surveillance applications in wireless sensor networks (WSNs) has gained much attention. However, a conventional MA-based WSN may have the issues of energy efficiency and task duration as the scale of the network is increased. In order to overcome the drawbacks of using a single MA, dispatching two or more MAs for data collection simultaneously is a promising alternative in a WSN. The authors first discuss the itinerary planning issues for multiple MAs: deciding the number of MAs to be dispatched, grouping of source nodes for each MA, routing of each MA for its assigned source nodes. The authors then survey the existing algorithms for these issues, and evaluate their performance by OPNET.

We present a simple but effective handoff protocol that enables continuous monitoring of ambulatory patients at home by means of resource-limited sensors. Our proposed system implements a 2-tier network: one created by wearable sensors used for vital signs collection, and another by a point-to-point link established between the body sensor network coordinator device and a fixed access point (AP). Upon experiencing poor signal reception in the latter network tier when the patient moves, the AP may instruct the sensor network coordinator to forward vital signs data through one of the wearable sensor nodes acting as a temporary relay if the sensor-AP link has a stronger signal. Our practical implementation of the proposed scheme reveals that this relayed data operation decreases packet loss rate down to 20% of the value otherwise obtained when solely using the point-to-point, coordinator-AP link. In particular, the wrist location yields the best results over alternative body sensor positions when patients walk at a 0.5 m/s.

Abstract There has been increasing interest in deploying a team of robots, or robot swarms, to fulfill certain complicate tasks such as surveillance. Since robot swarms may move to areas of far distance, it is important to have a pervasive networking environment for communications among robots, administrators, and mobile users. In this paper, we first propose a pervasive architecture to integrate wireless mesh networks and robot swarm networks to build a robot swarm communication network within the areas of special interest. Under the proposed architecture, one or more robots can get connected with a nearby mesh router and access the remote server, while a self‐organizing mobilead hocnetwork is formed within each swarm for communications among the robots. We then address and analyze many important issues and challenges. Finally, we describe our work to enable this architecture through a scalable algorithm for autonomous swarm deployment and ROBOTRAK, a socket‐based‐swarm monitoring and control toolkit. Extensive simulation results and demonstrations are presented to show the desirable features of the proposed algorithm and toolkit. Copyright © 2009 John Wiley & Sons, Ltd.

ABSTRACT For full cooperative diversity gains to be achieved while still maintaining spectral and energy efficiency, relay assignment schemes for cooperative communications have been extensively studied in recent research. These schemes select only the best relay from multiple relaying candidates to cooperate with a communication link. However, it is challenging to find the optimal relay in distributed wireless networks because of the dynamic nature of such networks. In this paper, we first formulate the problem of relay assignment as a noncooperative, mixed‐strategy, repeated game, where relaying candidates are modeled as rational players. We then propose a game‐theory‐based relay assignment schemeGTRA, in which each player plays against all the other players and determines whether to cooperate with a communication link on a packet‐by‐packet basis in a distributed manner. To adapt to dynamic environments, players utilized an adaptive learning algorithm, that is, modified‐regret‐matching algorithm, to learn optimal strategies of relay assignment, as well as to orient the game to converge to a set of correlated equilibriums, which is often more system efficient than a Nash equilibrium. To evaluate the performance ofGTRA, we compare it withBR, a fictitious two‐player game‐based approach. Simulation results have shown thatGTRAoutperformsBRin terms of network throughput, especially in environments where the channel fading becomes severe. It is also shown thatGTRAcan converge to a correlated equilibrium in a short period that enables theGTRAto work well in dynamic environments. Copyright © 2011 John Wiley & Sons, Ltd.

Nowadays, online gaming is one of the emerging industry on the Internet. Massively Multiplayer Online Games (MMORPG) is one of the most important type of online games. Research on MMORPGs always pay attention to the network situations, such as flow imbalance, system optimization and traffic identification. The results help the game designers and network protocol engineers to improve user game experience. In this paper, we perform traffic analysis and modeling in three distinct game scenarios over two different wireless network connections in World of Warcraft(WoW), which is one of the most popular MMORPGs among the world. In addition, we contribute a random traffic generator base on ns-2 which could be a open development platform for the MMORPGs.

Multimedia video sharing has been developed rapidly over the past years. P2P multimedia sharing mechanisms for P2P network such as PPLive, PPStream, Joost, have been used popularly. However, if Content Server and Client in the home network have to transmit via P2P sharing, P2P network must be adopted, thus it is unable to increase the network transmission speed through this intranet connection. Although there are DLNA, HAVi, and Jini protocols in the home network to share multimedia files, it cannot access P2P network due to the limitation of home network framework. Therefore, this paper extends the DLNA-based multimedia sharing system to P2P network on OSGi frameworks, so that users can access multimedia resource on P2P Network via DLNA, and P2P network users can apply P2P network mechanism in OSGI bundle to access shared DLNA multimedia resource in the home network.

As a multimedia information acquisition and processing method, wireless multimedia sensor network (WMSN) has great application potential in military civilian. Compared with traditional wireless sensor network, the routing design of WMSN should obtain more attention on the quality of transmission. This paper proposes a reliable routing based on energy prediction (REP), which includes energy prediction and power allocation mechanism. The introduced prediction mechanism makes the sensor nodes predict the remaining energy of other nodes, which dramatically reduces the overall information needed for balancing energy. based on the predicted result, REP can dynamically balance the energy consumption of nodes by power allocation. The simulation results prove the efficiency on energy equilibrium and reliability of the proposed REP routing.

Two Phase geographic Greedy Forwarding (TPGF) is a pure on-demand geographic greedy forwarding protocol for wireless multimedia sensor networks (WMSNs). Unlike position-based routing protocols, TPGF has explicit route discovery, i.e., a node greedily forwards a routing packet to the neighbor that is the closest one to the destination to build a route. Thus, TPGF is vulnerable to some greedy forwarding attacks, e.g., spoofing or modifying control packets. In this paper, we identify such vulnerabilities and propose corresponding countermeasures for TPGF, e.g., secure neighbor discovery, route discovery.

Radio frequency identification (RFID) is a kind of electronic identification technology that is becoming widely deployed. Compared to traditional RFID system, tags in the proposed smart RFID system would store not only the fixed ID information but also some information which is “active” and encoded in the form of mobile codes indicating the up-to-date situation and associated services' directives. In the proposed system, the service that the RFID tag bearer needs can be explained in a context-aware decision making system to provide a situation-aware system response and offer a good quality of service (QoS).

Outliers in wireless sensor networks (WSNs) are sensor nodes that issue attacks by abnormal behaviours and fake message dissemination. However, existing cryptographic techniques are hard to detect these inside attacks, which cause outlier recognition a critical and challenging issue for reliable and secure data dissemination in WSNs. To efficiently identify and isolate outliers, this study presents a novel outlier detection and countermeasure scheme (ODCS), which consists of three mechanisms: (i) abnormal event observation mechanism for network surveillance; (ii) exceptional message supervision mechanism for distinguishing fake messages by exploiting spatiotemporal correlation and consistency and (iii) abnormal behaviour supervision mechanism for the evaluation of node behaviour. The ODCS provides a heuristic methodology and does not need the knowledge about normal or malicious sensors in advance. This property makes the ODCS not only to distinguish and deal with various dynamic attacks automatically without advance learning, but also to reduce the requirement of capability for constrained nodes. In the ODCS, the communication is limited in a local range, such as one-hop or a cluster, which can reduce the communication frequency and circumscribe the session range further. Moreover, the ODCS provides countermeasures for different types of attacks, such as the rerouting scheme and the rekey security scheme, which can separate outliers from normal sensors and enhance the robustness of network, even when some nodes are compromised by adversary. Simulation results indicate that our approach can effectively detect and defend the outlier attack.

Compared to conventional wireless sensor networks (WSNs) that are operated based on the client-server computing model, mobile agent (MA) systems provide new capabilities for energy-efficient data dissemination by flexibly planning its itinerary for facilitating agent based data collection and aggregation. It has been known that finding the optimal itinerary is NP-hard and is still an open area of research. In this paper, we consider the impact of both data aggregation and energy- efficiency in sensor networks itinerary selection, We propose an itinerary energy minimum for first-source-selection (IEMF) algorithm, as well as the itinerary energy minimum algorithm (IEMA), the iterative version of IEMF. Our simulation experiments show that IEMF provides higher energy efficiency and lower delay compared to existing solutions, and IEMA outperforms IEMF with some moderate increase in computation complexity.

Abstract Routing protocols in wireless sensor networks (WSNs) typically employ a transmitter‐oriented approach in which the next hop node is selected based on neighbor or network information. This approach incurs a large overhead when the accurate neighbor information is needed for efficient and reliable routing. In this paper, a novel receiver‐oriented load‐balancing and reliable routing (RLRR) protocol is proposed. In RLRR, an intermediate node solicits next hop candidates, each of which is to respond with its own backoff time dubbed a temporal gradient (TG). In this way, the next hop is selected without any central coordination on a packet‐by‐packet basis. Thus, each node needs not maintain any neighbor information. The remaining energy level used to determine the TG is always accurate and up‐to‐date. Furthermore, neighbor nodes whose hop count is less than the soliciting node participate in the next‐hop selection process with loop‐free operation guarantee. Comprehensive simulations are carried out to show that RLRR achieves relatively longer network lifetime and higher reliability than other existing schemes. Copyright © 2007 John Wiley & Sons, Ltd.

Though data redundancy can be eliminated at aggregation point to reduce the amount of sensory data transmissions, it introduces new challenges due to multiple flows competing for the limited bandwidth in the vicinity of the aggregation point. On the other hand, waiting for multiple flows to arrive a

This paper addresses the problem of real-time video streaming over a bandwidth and energy constrained wireless sensor network (WSN). Considering the compressed video bit stream is extremely sensitive to transmission errors, and the constraints in bandwidth and energy in WSNs and delay in video delivery, we exploit the construction of an application-specific number of multiple disjoint paths to enlarge the aggregate bandwidth and facilitate load balancing and fast packet delivery. For efficient multi-path routing of real-time video frames, we propose a path priority scheduling algorithm to satisfy the delay constraint of video frames while balancing energy and bandwidth usage among all the available paths. In the case that the aggregate bandwidth is still not enough to satisfy the required coding rate, we further exploit a cross-layer technique for adaptive coding according to path status. The effectiveness of the proposed scheme is evaluated and demonstrated by simulations.

Recently, mobile agents have been proposed for efficient data dissemination in sensor networks. In the traditional client/server-based computing architecture, data at multiple sources is transferred to a destination; whereas, a task-specific executable code traverses the relevant sources to gather data in the mobile-agent based computing paradigm. As described in Hairong Qi, et al. (2003), many inherent advantages (e.g. scalability, extensibility, energy awareness, reliability) of the mobile agent architecture make it more suitable for sensor networks than the client/server architecture. In this paper, a mobile agent is exploited in three levels (e.g. node level, task level, and combined task level) to reduce the information redundancy and communication overhead.

The paper presents a modified version of the deficit round-robin (DRR) scheduling algorithm due to [M. Shreedha et al., June 1996]. The proposed scheduling scheme called weighted switch deficit round robin (WSDRR) categorises the different frame types of compressed video which are handled in separate queues and prioritizes time-sensitive and visually important data. WSDRR also introduces an overdraft threshold that basically allows a packet to be scheduled even if its flow's deficit is not large enough in a given scheduling round. By numerical experiments, WSDRR achieves better delay and delay jitter performance than DRR scheduling algorithm. Hence the delay, jitter can further meet requirement for real-time VBR video transmission.

In this paper, we propose a modified MAC protocol supporting real-time video traffic over the IEEE 802.11 WLAN. Investigating H.26L real-time video transmission over wireless IEEE 802.11b LANs, we present a novel hybrid automatic repeat request (ARQ) algorithm that efficiently combines forward error control (EEC) coding with the ARQ protocol based on multiple transmission stages. The scheme includes: (1) multiple transmission stages with corresponding ARQ feedback information that determines how many transmission stages should be activated; (2) conditional frame skipping algorithm based on accumulated feedback information. Through analysis and simulation, we show that multiple-stages based Hybrid ARQ scheme has high error recovery rate for real-time video frames. In case of severe unreliable channel which causes losing a lot of IP packets, at the cost of little end-to-end delay's increase, we obtain a peak signal-to-noise ratio improvement up to about 10dB compared to the hybrid ARQ proposed in I A. Majumdar et al. (2002).