In recent years, RF fingerprinting (RFF) has emerged as a promising technology for wireless device authentication. However, temporal variations in device load and temperature, along with channel effects, lead to inconsistencies in RFF distributions between training and testing phases. As a result, deep learning (DL)-based recognition models often suffer from degraded performance. To address this problem, we propose the first test-time-adaptation (TTA) approach to improve the domain generalization ability of RFF recognition models. We first analyze the causes of time-varying RFF distribution shifts, such as carrier frequency offset (CFO), and develop a physical impairment-based data augmentation strategy. Based on this, we further propose a physically information-aware prototype to guide the model for TTA. Our method requires no model retraining or labeled test samples, and is a lightweight, nonparametric solution. Finally, our approach is extensively evaluated using mobile phones with the IEEE 802.11 orthogonal frequency division multiplexing (OFDM) system, which demonstrates that our scheme can effectively improve RFF average recognition performance by about 7.8%.

Text-to-3D Scene Retrieval (T3SR) aims to retrieve 3D scenes that match users' linguistic queries, enabling intuitive access to 3D scene repositories. Existing approaches rely on joint embedding learning with large amounts of paired text–scene data, which is expensive to collect and often fails to generalize under open-vocabulary queries and diverse scene distributions. In this paper, we propose Struct-Align, a foundation-model-driven framework for zero-shot T3SR that eliminates the need for paired training data. Our key insight is to reformulate T3SR as a single-modality structural alignment problem by converting both 3D scenes and textual queries into a shared, schema-aligned textual representation compatible with pretrained text embedding models. To reliably derive such representations from complex 3D environments, we introduce a role-decomposed scene structuring pipeline that mitigates generative instability and produces semantically consistent scene depictions. To address the inherent semantic asymmetry between query and scene representations, we further propose a locality-aware structural matching strategy that explicitly localizes query intent and performs instance- and relation-level alignment within query-relevant substructures. Extensive experiments on multiple benchmarks demonstrate that Struct-Align outperforms both training-based and zero-shot baselines while exhibiting strong robustness to domain shift.

A novel threat, referred to as “Blackhat App Review Optimization (ARO)”, has emerged in the realm of app markets. In blackhat ARO, miscreants advertise and promote illicit services by manipulating the ranking of illicit app reviews. By exploiting the review ranking rules, these blackhat AROers inject reviews into high-ranking positions to facilitate the promotion of illicit content. However, little effort has been made to understand the scale, impact, techniques, and ecosystem associated with this emerging threat. In this paper, we report the first measurement study of the mobile app review ranking manipulation for illicit online promotion. Our findings reveal 41,296 poisoned app reviews on App Store and Google play, which are associated with 165 apps. Moreover, we unveil previously unreported techniques utilized by these blackhat AROers to exploit ranking rules. Additionally, our study explores the underlying malicious services (including illicit promotional review generation services and ranking manipulation services) and their revenues within this ecosystem, providing valuable insights for security practitioners and researchers.

We present SNH-SLAM, a novel expandable dense neural simultaneous localization and mapping (SLAM) method that constructs a neural field in real-time based on run-time observation. To reach this challenging goal without any scene prior, we utilize instant depth supervision to drive the extension of planar convex hulls, where a single hash table maintains multi-level feature units embedded in the planar convex hulls. This design facilitates high-fidelity, hole-free, and low-memory map reconstruction while adding only a tiny time burden to the training process. Our approach performs mapping by minimizing both RGBD-based re-rendering loss and Truncated Signed Distance Field (TSDF) loss. In addition, for camera tracking, our optimization strategy allows SNH-SLAM to converge faster on the pose estimation and maintain robustness. We evaluate our method on common benchmarks and compare it with existing dense neural RGB-D SLAM methods. The evaluation results show the competitiveness of the SNH-SLAM in tracking accuracy, reconstruction quality, memory usage, and frame processing speed. Project page:https://xiaoshumiao123.github.io.

With the rapid growth of 3D content, there is an increasing need for intelligent systems that can search for complex 3D shapes using simple natural language queries. However, existing approaches face significant limitations. They rely heavily on manually labeled datasets and use fixed similarity thresholds to determine matches, which restricts their ability to generalize and accurately retrieve novel or diverse 3D shapes. To bridge these gaps, this paper introduces Open3DSearch, the first attempt to address the challenge of open-domain text-to-shape precise retrieval. Our core idea is to transform 3D shapes into semantically representative 2D views, thereby enabling the task to be handled by mature large vision-language models (LVLMs) and allowing for explicit cross-modal matching judgments. To realize this concept, we design a view rendering strategy to mitigate potential information degradation during 3D-to-2D conversion while capturing the maximal amount of query-relevant information. To evaluate Open3DSearch and advance research in this field, we present the Uni3D-R benchmark dataset, designed to simulate precise associations between user queries and 3D shapes in open-domain contexts. Extensive quantitative and qualitative experiments demonstrate that Open3DSearch achieves state-of-the-art results.

To solve issues of frequent network topology changes to slow consensus speed, and low security in consensus algorithms within heterogeneous dynamic IoT systems, we propose a fast consensus algorithm of large-scale heterogeneous dynamic IoT nodes for DAG-based blockchain, LSHD_DAG. Firstly, an adaptive regional division method for heterogeneous dynamic nodes is proposed, which monitors nodes’ state and counts within each region, adjusting the boundaries of adjacent regions. Secondly, an event-triggered master-slave DAG chain design is proposed. When transaction information pertains to a single region, the transaction is processed as a local transaction to construct a regional DAG slave chain. If transaction information involves multiple regions, it is organized into a multi-regional transaction set and incorporated into the global DAG master chain. Next, a node grade identification mechanism that balances state and reputation factors is proposed. This mechanism adopts the LOF algorithm to classify or dynamically update node grades by considering node state and reputation evaluation results, assigning them identity permissions. Finally, a weighted voting consensus based on the master-slave DAG chain is introduced. Nearby honest nodes with stable movement are selected as consensus nodes, which perform multi-regional weighted voting consensus on transactions and transaction sets. This process concludes with Two-Way Pegging with multi-signature on the master-slave DAG, ensuring secure and rapid consensus for data in heterogeneous and dynamic IoT environments. The experimental results show that no matter how the number of nodes changes, LSHD_DAG can improve transaction throughput, and reduce latency and communication overhead, outperforming the CDBFT, DAG-D, and Avalanche.

Industrial cyber-physical systems (ICPSs) have significantly improved production efficiency, e.g., Siemens applied ICPS in its Amberg factory, which achieved 75% production automation. However, the security problems involved have not been completely solved, e.g., the source location privacy (SLP). Currently, with the expansion of the ICPS network size and the increasing number of devices, the existing defense process uses these device nodes as false nodes to enhance the security of the ICPS. However, this approach also results in additional energy consumption and transmission delays. To address the above challenges, we propose a solution to mix false sources and phantom strategies [i.e., phantom-backbone–fake (PBF)]. First, a relay phantom node selection algorithm is proposed because adversaries are prone to track source nodes through fixed routes. We aim to optimize the path from the source node to the relay node and then to the sink node to minimize transmission delays. Ultimately, we devise a comprehensive strategy that considers both energy efficiency and distance indicators for the selection of appropriate false nodes. Through simulation and analysis, we demonstrate that our approach improves security and overall network performance.

This paper addresses the problem of designing probability-guaranteed set-membership secure estimation algorithms for energy-constrained multi-sensor systems with multi-rate asynchronous samplings. An event-triggered strategy (ETS) is employed to minimize data transmission overhead while maintaining estimation accuracy by transmitting only essential data. A novel measurement model is proposed to accurately characterize the operation of the multi-sensor system under ETS, taking into account both high- and low-energy transmission (HLET) modes and random denial-of-service (DoS) attacks, which impact communication energy consumption and data security. To cope with the challenges posed by uncertain sampling periods, a new fusion estimation model is established, including a redefined fusion estimation weight matrix and the formulation of a probability-guaranteed set-membership secure fusion estimation algorithm. Furthermore, a recursive optimization algorithm based on linear matrix inequalities is utilized to determine the minimum ellipsoid of the design parameters. The effectiveness of the proposed algorithm is validated through simulation studies.

Neural implicit representations have recently shown promising progress in dense Simultaneous Localization And Mapping (SLAM). However, existing works have shortcomings in terms of reconstruction quality and real-time performance, mainly due to inflexible scene representation strategy without leveraging any prior information. In this paper, we introduce SP-SLAM, a novel neural RGB-D SLAM system that performs tracking and mapping in real-time. SP-SLAM computes depth images and establishes sparse voxel-encoded scene priors near the surface reconstruction. Simultaneously, we employ triplanes to store scene appearance information, striking a balance between achieving high-quality geometric texture mapping and minimizing memory consumption. Furthermore, in SP-SLAM, we introduce an effective optimization strategy for mapping, allowing the system to continuously optimize the poses of all historical input frames during runtime without increasing computational overhead. We conduct extensive evaluations on five benchmark datasets (Replica, ScanNet, TUM RGB-D, Synthetic RGB-D, 7-Scenes). The results demonstrate that, compared to existing methods, we achieve superior tracking accuracy and reconstruction quality, while running at a significantly faster speed.

In Earth observation, cloud severely affects the interpretation of optical satellites generated high-resolution images. Cloud-free optical images are vital for downstream tasks such as semantic segmentation and object detection. Thus, the elimination of clouds from optical imagery has emerged as a significant topic in remote sensing. Currently, most existing methods are proposed to leverage the texture information from auxiliary synthetic aperture radar (SAR) images to restore cloud-free images via direct channel merging. However, such a unified feature extraction approach often neglects the inherent distribution disparity between SAR and optical images—the result of differing imaging principles-potentially leading to significant feature loss. To this end, we introduce a network by jointing SAR and optical images multimodal and cross-attention network (MMCANet) to effectively extract multiscale contextual features from SAR imagery and integrate them with optical features. Specifically, instead of simple concatenation of the channels of SAR and optical images, we obtain high-dimensional features from them through independent feature extractors. The integration of these features is facilitated by a cross-attention mechanism that provides a more fine-grained amalgamation of information. Meanwhile, an atrous spatial pyramid pooling (ASPP) module is introduced into the integration of high-level features, which captures multiscale contextual information around clouded areas. In addition, we propose four advanced remote sensing image restoration algorithms that approach image restoration as a series of subtasks, gradually eliminating clouds to enhance performance. Comprehensive assessments show that MMCANet performs well on the SEN 12 MS-CR dataset with peak signal-to-noise ratio (PSNR) of 39.8871, structural similarity index (SSIM) of 0.9672, mean absolute error (MAE) of 0.0081, and spectral angle mapper (SAM) of 2.9884.

The rapid growth of the Internet of Things (IoT) has led to the widespread adoption of the IoT networks in numerous digital applications. To counter physical threats in these systems, automatic modulation classification (AMC) has emerged as an effective approach for identifying the modulation format of signals in noisy environments. However, identifying those threats can be particularly challenging due to the scarcity of labeled data, which is a common issue in various IoT applications, such as anomaly detection for unmanned aerial vehicles (UAVs) and intrusion detection in the IoT networks. Few-shot learning (FSL) offers a promising solution by enabling models to grasp the concepts of new classes using only a limited number of labeled samples. However, prevalent FSL techniques are primarily tailored for tasks in the computer vision domain and are not suitable for the wireless signal domain. Instead of designing a new FSL model, this work suggests a novel approach that enhances wireless signals to be more efficiently processed by the existing state-of-the-art (SOTA) FSL models. We present the semantic-consistent signal pretransformation (ScSP), a parameterized transformation architecture that ensures signals with identical semantics exhibit similar representations. ScSP is designed to integrate seamlessly with various SOTA FSL models for signal modulation recognition and supports commonly used deep learning backbones. Our evaluation indicates that ScSP boosts the performance of numerous SOTA FSL models, while preserving flexibility.

Given the rapid advancement of the physical industrial internet and the growing significance of military reconnaissance, a large amount of signal data will be generated, because signal transmission and reception are the basis of these scenarios. However, due to problems such as air noise, inconsistent transceiver technology, and hacker interference, a large amount of data labels will be lost. With the aim of solving this problem, we propose a Window-based Contrastive Learning for Signal Feature Reconstruction (WCL_SFR) method. This method divides the feature map into small windows and uses similarity to establish a contrastive learning mode, while incorporating a reconstruction module to improve the stability of the model’s capacity for extraction. On two commonly used signal datasets, WCL_SFR generates the most beneficial results, with an improvement of up to 28.32% compared to other contrastive learning methods. In order to simulate real scenarios, we also conducted cross-dataset migration experiments, which achieved accuracies of 65.36% and 66.17%, respectively, which greatly outperformed similar methods. Therefore, WCL_SFR is an innovative development in the field of unsupervised signal recognition.

The rapid proliferation of Internet of Things (IoT) devices has led to an increased need for robust and efficient intrusion detection systems capable of identifying and mitigating novel threats. Traditional methods often struggle with the scarcity of labeled anomaly data, which is highly consequential, particularly in the context of IoT. In this study, we propose a novel few-shot learning approach by leveraging a Multi-Stage Attention Siamese Network (MASiNet) for network traffic intrusion detection based on meta-learning framework. Unlike traditional methods, the proposed MASiNet model is capable of detecting intrusions with minimal labeled samples, addressing the challenge of scarce anomaly data. The model is trained using various attack samples and evaluates unknown samples by comparing similarities with a small set of known attack types. A well-structured cost function design, incorporating two specific losses, is introduced to optimize the effectiveness of the training process. Tested on the NSL_KDD and UNSW-NB15 datasets in a simulated few-shot learning environment, the MASiNet model demonstrates superior performance in terms of accuracy, precision, False Alarm Rate (FAR), outperforming existing methods. Furthermore, we have validated our approach through real-world evaluations. The proposed method provides an effective solution for intrusion detection in the context of few-shot learning, offering a proficient solution that aligns with the dynamic nature of IoT networks.

In order to solve the problems in the blockchain consensus algorithm, such as slow consensus speed, high resource consumption, and low consensus security due to excessive large-scale node data volume and Byzantine attacks in the Internet of Things (IoT) system, we propose a large-scale node lightweight consensus algorithm of blockchain for IoT (LNLCA). First, a transaction set construction mechanism is proposed to improve consensus efficiency and security. The mechanism packages multiple data monitored by IoT nodes into data transactions, and builds the transaction set. Then, it constructs nonconflict subsets and conflict subsets. Second, an adjacent parent node sampling and response mechanism is proposed to reduce the consumption of communication resources. The new transaction set selects nearby parent nodes based on the time distance summation method and collaborates to batch verify each transaction in the transaction set. Finally, an efficient consistent consensus based on transaction set directed acyclic graph (DAG) is proposed to quickly vote for each transaction in the transaction set, thereby constructing the transaction set DAG for batch uploading to the chain, and achieving a secure and lightweight consensus on IoT data. The experimental results show that no matter how the number of Byzantine nodes changes, LNLCA can improve transaction throughput, and reduce transaction delay and communication overhead, which outperforms the credit-delegated Byzantine fault tolerance, Avalanche, and Hashgraph.

ICPS software and hardware suffer from low update frequency, making it easier for insiders to bypass external defenses and launch concealed destructive attacks. To address these concerns, we design a device fingerprinting method based on multi-physical features, augmenting current intrusion detection techniques in the ICPS environment. In this article, we use the sorting system as an example, demonstrating that the proposed device fingerprinting technology has generality in the intrusion detection of ICPS control flow. Specifically, we first formalize the physical model of the sorting system to analyze the critical device features. Then, we extract these physical features from the sensor data collected in a physical testbed. Utilizing featurized data, we train a classifier that generates fingerprints in real-time in the production environment. Moreover, we develop a differential detection model based on device fingerprints to discover stealthy insider attacks efficiently. We evaluate the proposed method in a real-world testbed. Experiment results show that the detecting performance of classifiers approaches 100% when the the number of component types is small.

The recent flourish of deep learning on various tasks is largely accredited to the rich and high-quality labeled data. Nonetheless, collecting sufficient labeled samples is not very practical for many real applications. Few-shot Learning (FSL) provides a promising solution that allows a model to learn the concept of novel classes with a few labeled samples. However, many existing FSL methods are only designed for computer vision tasks and are not suitable for radio signal recognition. This paper calls for a radically different approach to FSL: in contrast to developing a new FSL model, we should focus on transforming the radio signal to be better processed by the state-of-the-art (SOTA) FSL model. We propose Modulated Signal Pre-transformation (MSP), a parameterized radio signal transformation framework that encourages the signals having the same semantics to have similar representations. MSP currently adapts to various SOTA FSL models for signal modulation recognition and can support the mainstream deep learning backbone. Evaluation results show that MSP improves the performance gains for many SOTA FSL models while maintaining flexibility.

Mode decomposition methods are the current workhorse for the analysis of non-stationary signals. However, current attempts at these methods mainly focus on improving accuracy, leaving computational efficiency untouched. To this end, we leverage the neural mode decomposition technique and propose an open-source Neural Mode Estimation (NME) to deliver a large speedup (at least 50×) while maintaining accuracy. Specifically, we transform the mode decomposition problem into an extremum problem of a functional in the cosine transform domain and train a neural network to approximate the solution. We demonstrate in extensive empirical results that NME can provide an improved trade-off between speed and accuracy, enabling fast, high-quality, stable mode decomposition of non-stationary signals.

We study the problem of object reconstruction in a multi-agent collaboration scenario. Specifically, we focus on the reconstruction of specific goals through several cooperative agents equipped with vision sensors to achieve higher efficiency than single agents. Our main insight is that a complete 3D object can be split into several local 3D models and assigned to different agents. In addition, we can use the salient characteristics of the collaboration agent itself to help realize the integration of local models. We develop a novel pipeline that first restores local 3D models from the images obtained from different agents, then the relative poses between collaborative agents are estimated by aligning intrinsic features. After that, all local models are integrated using the estimated parameters. Extensive experiments show that our proposed method is capable of accurately reconstructing 3D objects in the real world in a multi-agent collaborative manner. The full reconstruction pipeline is released to the public as an open-source project.

Automatic modulation classification (AMC) is an important technology for the monitoring, management, and control of communication systems. In recent years, machine learning approaches are becoming popular to improve the effectiveness of AMC for radio signals. However, the automatic modulation open-set recognition (AMOSR) scheme that aims to identify the known modulation types and recognize the unknown modulation signals is not well studied. Therefore, in this paper, we propose a novel multi-modal marginal prototype framework for radio frequency (RF) signals (MMPRF) to improve AMOSR performance. First, MMPRF addresses the problem of simultaneous recognition of closed and open sets by partitioning the feature space in the way of one versus other and marginal restrictions. Second, we exploit the wireless signal domain knowledge to extract a series of signal-related features to enhance the AMOSR capability. In addition, we propose a GAN-based unknown sample generation strategy to allow the model to understand the unknown world. Finally, we conduct extensive experiments on several publicly available radio modulation data, and experimental results show that our proposed MMPRF outperforms the state-of-the-art AMOSR methods.

In recent years, a surging number of unmanned aerial vehicles (UAVs) are pervasively utilized in many areas. However, the increasing number of UAVs may cause privacy and security issues such as voyeurism and espionage. It is critical for individuals or organizations to manage their behaviors and proactively prevent the misbehaved invasion of unauthorized UAVs through effective anomaly detection. The UAV anomaly detection framework needs to cope with complex signals in the noisy-prone environments and to function with very limited labeled samples. This paper proposesBisSiam, a novel framework that is capable of identifying UAV presence, types and operation modes.BisSiamconverts UAVs signals to bispectrum as the input and exploits a siamese network based contrastive learning model to learn the vector encoding. A sampling mechanism is proposed for optimizing the sample size involved in the model training whilst ensuring the model accuracy without compromising the training efficiency. Finally, we present a similarity-based fingerprint matching mechanism for detecting unseen UAVs without the need of retraining the whole model. Experiment results show that our approach outperforms other baselines and can reach 92.85% accuracy of UAV type detection in unsupervised learning scenarios. 91.4% accuracy can be achieved whenBisSiamis used for detecting the UAV type of the out-of-sample UAVs.

Convolutional neural networks (CNNs), such as the time-delay neural network (TDNN), have shown their remarkable capability in learning speaker embedding. However, they meanwhile bring a huge computational cost in storage size, processing, and memory. Discovering the specialized CNN that meets a specific constraint requires a substantial effort of human experts. Compared with hand-designed approaches, neural architecture search (NAS) appears as a practical technique in automating the manual architecture design process and has attracted increasing interest in spoken language processing tasks such as speaker recognition. In this paper, we propose EfficientTDNN, an efficient architecture search framework consisting of a TDNN-based supernet and a TDNN-NAS algorithm. The proposed supernet introduces temporal convolution of different ranges of the receptive field and feature aggregation of various resolutions from different layers to TDNN. On top of it, the TDNN-NAS algorithm quickly searches for the desired TDNN architecture via weight-sharing subnets, which surprisingly reduces computation while handling the vast number of devices with various resources requirements. Experimental results on the VoxCeleb dataset show the proposed EfficientTDNN enables approximate$10^{13}$architectures concerning depth, kernel, and width. Considering different computation constraints, it achieves a 2.20% equal error rate (EER) with 204 M multiply-accumulate operations (MACs), 1.41% EER with 571 M MACs as well as 0.94% EER with 1.45 G MACs. Comprehensive investigations suggest that the trained supernet generalizes subnets not sampled during training and obtains a favorable trade-off between accuracy and efficiency.

Electronic Stability Program (ESP) is widely used in modern vehicles. Its safety and stability largely depend on the strength and reliability of the MEMS gyroscope. However, the tight coupling between this sensor and the environment brings significant safety hazards to the vehicle. In this study, we describe the physical vulnerability of gyroscopes to high-frequency acoustics and introduce methods for finding resonant frequencies. We devised two methods to inject the attack signal into audio files to make the acoustic attack more stealthy. The realized attack is non-intrusive and does not require tampering with the ESP hardware device, making attack detection more difficult. We also consider a neural network-based defense strategy and verify its effectiveness. The construction of the vehicle simulation system and the above experiments are completed in the co-simulation environment of Carsim and Simulink.

Cyber-physical systems (CPS) have been deployed in many areas and have reached unprecedented levels of performance and efficiency. However, the security and privacy problems in CPS have not been properly addressed, e.g., the monitored source location can be inferred by an attacker, which can substantially undermine the reliability of CPS. Unfortunately, the existing techniques to protect against the leakage of the source location do not achieve an acceptable balance among the source location privacy, transmission delay, and energy consumption to guarantee high reliability. To address this issue, we propose an attacker location evaluation-based fake source scheduling (FSSE) for source location privacy in CPS to enhance the privacy level and maintain the system performance. The proposed FSSE contains two main phases. The first, backbone construction, is dependent on the probability of capture derived from the communication information of self and neighboring nodes. This phase aims to build a backbone to form a baseline with respect to the source location privacy and transmission delay. The second phase is fake message scheduling, which is established to provide a trade-off among privacy, transmission delay, and communication overhead in terms of the hypothesized location of the attacker by using stochastic processes. Through analysis and simulation, we demonstrate that the proposed method has a more stable privacy level and more efficient transmission delay and energy consumption than the three compared algorithms, i.e., phantom routing, tree-based diversionary routing, and dynamic fake source selection.

In this paper, we study the correlation of graph da-ta's anonymity, utility, and de-anonymity. Our main contributions include four perspectives. First, to the best of our knowledge, we conduct the first Anonymity-Utility-De-anonymity (AUD) correlation quantification for graph data and obtain close-forms for such correlation under both a preliminary mathematical model and a general data model. Second, we integrate our AUD quantification to SecGraph [31], a recently published Secure Graph data sharing/publishing system, and extend it to Sec-Graph+. Compared to SecGraph, SecGraph+ is an improved and enhanced uniform and open-source system for comprehensively studying graph anonymization, de-anonymization, and utility evaluation. Third, based on our AUD quantification, we evaluate the anonymity, utility, and de-anonymity of 12 real world graph datasets which are generated from various computer systems and services. The results show that the achievable anonymity/de-anonymity depends on multiple factors, e.g., the preserved data utility, the quality of the employed auxiliary data. Finally, we apply our AUD quantification to evaluate the performance of state-of-the-art anonymization and de-anonymization techniques. Interestingly, we find that there is still significant space to improve state-of-the-art de-anonymization attacks. We also explicitly and quantitatively demonstrate such possible improvement space.

With the flourishing of smart mobile devices (e.g., smartphones, tablets), development of mobile cloud computing has received more and more attentions from both industry and academia. Compared with the traditional way of executing large- scale computational tasks on powerful desktop computers and the cloud, mobile cloud computing is featured by the ubiquitous availability, flexibility, and low-cost. However, this feature also brings challenges when we build the satisfactory mobile computing system. First, the computational power on a mobile device is not comparable with that on a personal computer such that many computation-intensive tasks cannot be independently handled by mobile devices. Second, offloading computational tasks to the cloud introduces additional monetary costs (e.g. wireless communication cost, computational service cost), which may be pricy for users. In this paper, we propose a novel connectivity- aware task scheduling paradigm to enable mobile device users to accomplish computation-intensive tasks cooperatively in the device-to-device (D2D) network by incorporating the "fog" - aggregate of computational powers in the ad-hoc. A supernode at the base station is responsible for scheduling cooperation tasks based on user mobility. To further enhance the quality of experience (QoE) for the users, we propose a lightweight heuristic algorithm to perform task scheduling to ensure low cooperative task execution time. Simulation results show that our cooperative paradigm efficiently reduces the average task execution time for mobile device users in the D2D network.

Cloud service selection and financial expense are two main concerns of users considering adoption of cloud computing services. In this paper, we propose a novel cloud federation that is cognitive to the dynamic prices. The cloud federation system first determines on which cloud services should the user applications be deployed. Then, when a cloud provider is charging too high for a VM, the proposed system automatically migrates user tasks to a cloud system that is charging at a lower rate. We discuss the architectural framework and platform design, provide a mathematic formulation and investigate a total service fee minimization approach with privacy constraints. Preliminary simulation results demonstrate the proposed system can lower the cost of cloud services by exploiting the advantages of different price policies provided by multiple cloud providers.

Cloud gaming systems host the game in the cloud, while Gameplays and views are streamed to the players' terminals in the form of encoded video frames. To address the high-bandwidth issue of real-time gaming video transmission, we have proposed a cloudlet-assisted multiplayer cloud gaming system to encourage cooperative video sharing, which exploits the similarities of video frames among multiple players in the same crowd playing the same game via a secondary ad hoc network. In this paper, we provide a detailed modeling of the proposed system, including the correlation between video frames, mobility of terminal devices, and diversity of network quality of service for distinct players. With necessary mathematical formulations, we study the players' behaviors regarding the cooperative sharing patterns to optimize the system performance in terms of the quality of users' experience. Also, heuristic algorithms are proposed to reduce the computational complexity. Empirical study and trace-driven simulation results illustrate the impact of mobility on the system performance and show that the proposed solution is able to provide better quality of experience compared with the existing platform.

Cloud gaming systems host the game in the cloud, and stream players' gaming videos to the terminals in the form of encode video frames. To address the high bandwidth issue of real-time gaming video transmission, a cloudlet-assisted multiplayer cloud gaming system was proposed to encourage cooperative video sharing via a secondary ad-hoc network, on the purpose of exploiting the similarities of video frames among multiple players in a same game. However, the video cooperative sharing among players also introduces fairness problems. In this paper, we complete the ad hoc cloudlet-assisted cloud gaming system by further considering the mobility of terminal devices and the diversity of network quality for distinct players. With mathematical formulation, we study the players' behavior in cooperative sharing patterns and propose a reputation-based multiplayer fairness scheme in terms of frame encoding. Experimental results illustrate the impact of mobility on the system performance and evaluate that the proposed solution provides better fairness gaming ecosystem compared to the existing platform.