Large vision-language models (LVLMs) have gained widespread attention in the medical field for their outstanding capability in handling image-text representations. However, the misalignment between medical images and clinical text presents factuality challenges for Medical LVLMs (Med-LVLMs), often resulting in hallucinations. Multimodal Chain-of-Thought (MCoT) can reduce factual errors of Med-LVLMs by encouraging explicit step-by-step reasoning, but it poses two major challenges. First, factually accurate medical rationales are crucial for aligning medical images with the corresponding clinical texts, yet existing Med-LVLMs struggle to generate such rationales. Second, if the model's initial prediction is correct, its inherent knowledge can be disrupted by an over-reliance on the generated medical rationale, resulting in an incorrect answer. To address these challenges, we propose MMReT, a novel multimodal medical reasoning tuning approach designed to improve the factual accuracy of Med-LVLMs. First, we employ carefully designed prompts to guide GPT-4o in generating high-quality medical rationales, which are then used to fine-tune the original Med-LVLM. Second, to address errors stemming from excessive reliance on generated rationales, we introduce medical reasoning preference fine-tuning, which encourages the model to maintain an appropriate balance between leveraging its inherent knowledge and incorporating generated medical rationale. Experimental results show that MMReT substantially enhances the factuality of Med-LVLMs, outperforming previous methods with average improvements of 8.0% on VQA-RAD and 11.6% on SLAKE in factual accuracy.

Dose planning is essential in radiotherapy for cancer patients, yet current practice relies on iterative manual optimization, underscoring the need for automated prediction. Existing deep learning approaches remain limited because they often ignore the 3D spatial relationships between tumors and surrounding organs at risk (OARs), and clinical priors on safe dose thresholds. To overcome these limitations, we propose DKVMU-Net, a distance-aware and knowledge-driven Vision Mamba U-Net for automated dose prediction. Our framework incorporates Vision Mamba blocks to capture global, long-range dependencies from CT scans and OAR signed distance field (SDF) maps, which naturally encode spatial information. Additionally, we introduce a deformable dynamic feature enhancement module (DDFEM) for texture refinement, followed by a linear crossattention fusion module to improve cross-modality integration. A customized loss function is also designed to incorporate prior knowledge of OAR dose constraints, ensuring optimal target coverage and OAR protection. To alleviate the scarcity of doseplanning datasets, we collect an in-house radiotherapy lung cancer dataset (RLCD), consisting of CT volumes, OAR masks, and corresponding SDF maps from 116 patients. We evaluate our DKVMU-Net on both the in-house dataset and public available OpenKBP dataset. Compared with the sate-of-the-art method, our approach achieves an 11.6 % improvement in dose score (1.641 vs. 1.857) and 26.3 % in DVH score (6.481 vs. 8.799) on RLCD, and a 7.8 % improvement in dose score (2.421 vs. 2.626) and 13.9 % in DVH score (1.057 vs. 1.227) on OpenKBP. These results demonstrate the robustness and effectiveness of our approach.

Deformable image registration is essential in medical applications, as accurately estimating organ displacements across respiratory phases enables precise radiation dose planning in dynamic environments, mitigates damage to organs at risk (OARs), and thus improves patients' health-related quality of life. Although current learning-based methods have achieved impressive performance in small deformation registration, challenges remain due to their limited ability to capture large deformations occurring during respiration. To address this issue, we propose a novel Mamba-based hierarchical registration framework that effectively extracts both global and local features for accurate deformation prediction. Specifically, given a pair of source and target 3DCT volumes, we incorporate a foundation model pretrained on medical image registration tasks to enhance alignment accuracy. We further propose a directional-deformable Mamba scheme to facilitate global context extraction and local motion awareness. The directional Mamba component scans input features from multiple orientations to achieve broad contextual perception, while the deformable Mamba module employs adaptive directional scanning strategies to capture dynamic local variations. To overcome the scarcity of annotated respiratory data, we also collect a new respiratory lung cancer dataset comprising 100 annotated phases from 20 patients. Experimental results on our in-house dataset demonstrate that our method outperforms state-of-the-art approaches, achieving a 1.3 % improvement in overall Dice accuracy and a 1.6 dB increase in PSNR, underscoring its strong potential for clinical deployment. Code and test data are available at: https://github.com/yangyangshi806/Mamba_based_Registration.

Given the capability of multimodal data to provide information from multiple perspectives, it is beneficial for improving the accuracy of Alzheimer’s disease (AD) classification. However, during practical multimodal learning, there is a phenomenon where certain modalities dominate the decision-making, leading to insufficient learning from other modalities. Moreover, redundant information within multimodal data can also hinder accurate classification decisions. Therefore, we propose a robust multimodal representation learning method for AD classification. Specifically, we first construct dedicated encoders for each multimodal data, including structural Magnetic Resonance Imaging (sMRI) images, Positron Emission Tomography (PET) images, and Mini-Mental State Examination (MMSE) scores, to extract their respective representations. Then, we employ the information bottleneck (IB) theory to guide the model to retain classification-related information in multimodal representations while reducing redundancy among modalities. Furthermore, to promote a balanced fusion of multimodal data, we redefine the classification confidence of each modality’s representation using an orthogonal weight classifier and then introduce a regularization term to amplify the prediction score differences for modalities with lower confidence. The experimental results on the Alzheimer’s Disease Neuroimaging Initiative (ADNI) dataset demonstrate that our method enhances the robustness of multimodal representations and achieves promising performance in AD-related classification tasks.

In this paper, we tackle the common problem of misclassifying bone gaps in multi-region bone tissue segmentation within 3D medical image analysis by introducing BT-Net, an innovative multi-scale U-Net architecture. The key innovations are: (1) Boundary Rendering Module: Uses morphological methods to extract and smooth image boundaries, improving segmentation accuracy in bone gaps and complex regions; (2) Transformer Fusion Block: Achieves multi-scale feature fusion through attention mechanisms, fully integrating contextual information from multi-resolution images to enhance the model’s global perception and representation of complex skeletal structures; (3) Adaptive Morphological Loss: Utilizes variable dilation kernels to precisely measure differences between predicted and true boundaries, strengthening the model’s focus on boundary regions. BT-Net effectively addressed bone gap misclassification in both the hip joint segmentation task on TotalSegmentator v2 and the spine segmentation task on CTSpine1K, achieving Dice scores of 91.07% and 91.54%, respectively. BT-Net outperforms existing state-of-the-art methods, demonstrating the effectiveness and feasibility of our approach in improving bone tissue segmentation accuracy. The code is available at: https://github.com/xiongjiula/BT-Net

Accurate traffic speed prediction holds immense significance in mitigating traffic congestion and enhancing traffic safety. However, traffic data exhibit distinct patterns across different cycles (such as weekdays, weekends, and holidays), making it challenging for traditional models to effectively capture this multiperiod heterogeneity in traffic data. Furthermore, most existing research on traffic speed prediction struggles to efficiently capture the spatiotemporal characteristics of dynamic traffic data simultaneously. To tackle these challenges, this paper first introduces spatiotemporal‐aware position encoding (STAPE) technology, which addresses the multiperiod heterogeneity in traffic data by integrating temporal cycle information with spatial position information. Second, a multilevel spatiotemporal feature extraction architecture is designed, leveraging graph convolutional network (GCN) to capture the topological structure and spatial features of the traffic road network. By applying gated recurrent unit (GRU) to capture the temporal dependencies of traffic data, and combining GCN and GRU in multiple stages, this architecture deeply explores the spatiotemporal features of traffic data. Additionally, this paper integrates a multihead attention mechanism, which, in conjunction with the parallelized attention channel adaptive mechanism and the multilevel spatiotemporal feature extraction architecture, enhances the model’s ability to adaptively model different spatiotemporal patterns dynamically, thereby efficiently capturing the dynamically changing spatiotemporal features. Extensive performance evaluation experiments conducted on the METR‐LA and PEMS‐BAY datasets demonstrate that the predictive performance of the proposed model surpasses that of nine other baseline methods.

Cancer is an extremely complex disease, whose occurrence and development are influenced by a multitude of factors, among which the abnormal activity of cancer driver genes plays a crucial role in the pathological process. Identifying these genes allows researchers to understand pathogenic mechanisms and biological functions of cancer, facilitating the development of targeted therapies. Current methods for identifying driver genes often ignore the synergism among genes and the importance of features, thereby affecting identification accuracy. In this paper, we propose a cancer driver genes identification method called HMFS, which is based on the hierarchical multi-feature synergy model. Firstly, a hypergraph is constructed using Node2vec and K-means algorithm. By analyzing the topological feature and mutual exclusion degree of genes in each hyperedge, the Mutation Aggregation Coefficient is extracted. Then, based on the functional expression mechanism of genes, differential expression analysis is performed using miRNA and mRNA expression data. Finally, by analyzing the importance among features, the Hierarchical Multi-Feature Synergy is proposed for features fusion. In this paper, experiments are conducted on three real cancer datasets. Compared with seven representative methods, HMFS has the best performance on all evaluation indicators.

Graph neural networks (GNNs) have achieved remarkable success in learning graph representations, especially graph Transformers, which have recently shown superior performance on various graph mining tasks. However, the graph Transformer generally treats nodes as tokens, which results in quadratic complexity regarding the number of nodes during self-attention computation. The graph multilayer perceptron (MLP) mixer addresses this challenge using the efficient MLP Mixer technique from computer vision. However, the time-consuming process of extracting graph tokens limits its performance. In this article, we present a novel architecture named ChebMixer, a newly proposed graph MLP Mixer that uses fast Chebyshev polynomials-based spectral filtering to extract a sequence of tokens. First, we produce multiscale representations of graph nodes via fast Chebyshev polynomial-based spectral filtering. Next, we consider each node's multiscale representations as a sequence of tokens and refine the node representation with an effective MLP Mixer. Finally, we aggregate the multiscale representations of nodes through Chebyshev interpolation. Owing to the powerful representation capabilities and fast computational properties of the MLP Mixer, we can quickly extract more informative node representations to improve the performance of downstream tasks. The experimental results prove our significant improvements in various scenarios, ranging from homogeneous and heterophilic graph node classification to medical image segmentation. Compared with NAGphormer, the average performance improved by 1.45% on homogeneous graphs and 4.15% on heterophilic graphs. And the average performance improved by 1.39% on medical image segmentation tasks compared with VM-UNet. We will release the source code after this article is accepted.

Online group discussions play an important role in education reform by facilitating collaborative learning and knowledge sharing among participants. However, instructors face significant challenges in monitoring discussion progress, tracking student performance and understanding interaction dynamics due to overlapping conversations, time-varying participant behaviors, and hidden interaction patterns. To address these challenges, we propose GroupTrackVis, an interactive visual analytics system that incorporates both advanced algorithms and novel visualization designs, to help instructors analyze group discussions mainly from three perspectives: topic evolution, student performance, and interaction. GroupTrackVis proposes an enhanced topic segmentation algorithm by incorporating word vector weighting and reply relationship analysis, effectively disentangling overlapping discussions. It also extracts six key behavioral attributes from multimodal educational data, offering a comprehensive view of student performance and providing insights into the key factors driving learning outcomes. Additionally, a multi-layer tree network with edge bundling techniques is implemented to clearly visualize the dynamic evolution of student interactions. The integration of algorithms with interactive visualizations enables instructors to explore discussions quickly and dynamically adjust their analysis as the discussion evolves. The effectiveness of GroupTrackVis is demonstrated through two case studies, a user study, and expert interviews, highlighting its ability to support instructors in identifying engaged and disengaged students, and tracking discussion dynamics.

Vision-language foundational models have achieved commendable results on related tasks. However, their application to medical tasks is still limited due to issues arising from data biases. Currently, leveraging existing foundational models to improve medical tasks remains a challenge. To this end, this paper proposes a strong multimodal representation learning method based on cross-domain distillation handling structural Magnetic Resonance Imaging (sMRI), Positron Emission Computed Tomograph (PET) images, and mini-mental state examination (MMSE) score for Alzheimer’s disease (AD) classification. Specifically, we establish a text-to-image cross-domain distillation learning framework, enabling a text encoder pre-trained on general visual recognition tasks to guide the training of sMRI and PET image feature extractors. Simultaneously, positional encoding is used to extract the magnitude features of MMSE scores. Based on the multimodal representations extracted from sMRI, PET images, and MMSE scores, we perform a self-attention operation equipped with a gating mechanism for multimodal feature fusion. This mechanism controls the contribution of each modality representation to the classification decision, dynamically strengthening or weakening specific modality representations and helping construct stronger fused features for AD classification. Our method undergoes 5-fold cross-validation on the widely used ADNI dataset, and comparative experimental results demonstrate that our method achieves advanced performance in two AD-related binary classification tasks.

Deep learning (DL) has been applied in billions of mobile devices due to its astonishing performance in image, text, and audio processing. However, limited by the computing capability of mobile devices, a large amount of DL inference tasks need to be offloaded to edge or cloud servers, which makes powerful GPU servers are struggling to ensure the quality of service(QoS). To better utilize the highly parallel computing architecture of GPU to improve the QoS, we propose BatOpt, a framework that uses dynamic batch processing to strike a good balance between service latency and GPU memory usage in DL inference services. Specifically, BatOpt innovatively models the DL inference service as a$M/G(a,b)/1/N$queue, with the consideration of stochastic task arrivals, which enables it to predict the service latency accurately in different system states. Furthermore, we propose an optimization algorithm to trade off the service latency and GPU memory usage in different system states by analyzing the queueing model. We have implemented BatOpt on Pytorch and evaluated it on an RTX 2080 GPU using real DL models. BatOpt brings up to 31x and 4.3x times performance boost in terms of service latency, compared to single-input and fixed-batch-size strategies, respectively. And BatOpt's maximum GPU memory usage is only 0.3x that of greedy-dynamic-batch-size strategy on the premise of the same service latency.

Regularization is a crucial technology to improve the generalization of deep neural networks. However, traditional regularization method approaches are all scenario-specific, because they are generally with ingeniously designed feature representations from input layer, hidden layer, and output layer, which increase the difficulty of model development and interpretation. To this end, a novel practical and flexible regularization method is presented to obtain higher generalization and interpretability. Specifically, the feature maps are decoupled by global suppression and partial suppression from various scales and locate the salient feature with strong low-resolution semantic information. Moreover, the guided discarding specification for feature decoupling by measuring the feature contributions to network decisions, leads to the logics with better interpretability. Subsequently, the max values of the feature map are suppressed by discarding the corresponding salient features. Comprehensive experiments demonstrate that the proposed adaptive regularization outperforms the state-of-the-art performance in image classification accuracy, generalization, and interpretability on several widely used datasets. And adaptive regularization helps the network to mine the connection between salient features, nonsalient features, and ground truth, encouraging the network to construct multiple layers of feature associations.

Blockchain technology, with its unique decentralized and tamper-resistant features, is being utilized to address the issue of information silos in traditional electronic healthcare. However, as healthcare data sources become increasingly complex and numerous, the limited scalability and transaction throughput of traditional blockchains result in challenges such as slow processing efficiency and vulnerability to attacks in modern healthcare blockchain systems. To address these issues, we propose a Dynamic Security Resource Configuration scheme based on Medical Consortium Blockchain (MC-DSC). This scheme allows for dynamic blockchain configuration based on the varying urgency levels of data, enhancing data processing efficiency. It ensures the security of the data processing process through identity control and data encryption methods. Experimental results demonstrate that, compared to existing blockchain configuration algorithms (SsHealth and Medge-Chain), the proposed scheme achieves approximately a 15% performance improvement by dynamically configuring the blockchain for three data types (secure, urgent, and normal). Additionally, the security module accounts for only 7% of the total time overhead, efficiently safeguarding the security of healthcare data while effectively handling data with different urgency levels.

Reference-based image super-resolution (RefSR) aims to reconstruct high-resolution (HR) images from low-resolution (LR) images by introducing HR reference images. The key step of RefSR is to transfer reference features to LR features. However, existing methods still lack an efficient transfer mechanism, resulting in blurry details in the generated image. In this article, we propose a double-layer search module and an adaptive pooling fusion module group for reference-based image super-resolution, called DLASR. Based on the re-search strategy, the double-layer search module can produce an accurate index map and score map. These two maps are used to filter out accurate reference features, which greatly increases the efficiency of feature transfer in the later stage. Through two continuous feature-enhancement steps, the adaptive pooling fusion module group can transfer more valuable reference features to the corresponding LR features. In addition, a structure reconstruction module is proposed to recover the geometric information of the images, which further improves the visual quality of the generated image. We conduct comparative experiments on a variety of datasets, and the results prove that DLASR achieves significant improvements over other state-of-the-art methods, in terms of quantitative accuracy and qualitative visual effect. The code is available at https://github.com/clttyou/DLASR.

The visual information processing technology based on deep learning can play many important yet assistant roles for unmanned aerial vehicles (UAV) navigation in complex environments. Traditional centralized architectures usually rely on a cloud server to perform model inference tasks, which can lead to long communication latency. Using transfer learning to unload deep neural networks to the edge-fog collaborative networks has become a new paradigm for dealing with the conflicts between computing resources and communication latency. However, ensuring the security of edge-fog collaborative networks entity remains challenging. For such, we propose an anonymous authentication and group key agreement scheme for the UAV-enabled edge-fog collaborative networks, consisting of the UAV authentication protocol and the collaborative networks authentication protocol. Utilizing the AVISPA assessment tool and security analysis, the security requirements and functional features of the proposed scheme are demonstrated. From the performance results of the proposed scheme, we show that it is superior to existing authentication schemes and promising.

In this paper, we propose a wavelet-aware transformer network (WATNet) for multi-contrast knee MRI super-resolution. Unlike conventional image domain-based super-resolution methods that can not explicitly model the lost high-frequency information, our WATNet endeavors to adaptively fuse the complementary frequency information of the multi-contrast image in the wavelet domain and further refine it in the image domain. The proposed WATNet consists of the multi-scale wavelet transformation (MSWT) module, wavelet-aware transformer (WAT) module, and reconstruction (Rec) module. Specifically, the MSWT module learns to transform the MR image to multi-scale wavelet domain features by the wavelet transformation. The WAT module can adaptively search and transfer similar wavelet domain reference information to the low-resolution one. The Rec module can restore high-quality images in the image domain. To further capture more high-frequency details, we also design the wavelet-based high-frequency loss. The qualitative and quantitative experimental results indicate that our proposed WATNet outperforms most state-of-the-art methods.

Facial expression recognition (FER) plays a significant role in our daily life. However, annotation ambiguity in the datasets could greatly hinder the performance. In this paper, we address FER task via label distribution learning paradigm, and develop a dual-branch Adaptive Distribution Fusion (AdaDF) framework. One auxiliary branch is constructed to obtain the label distributions of samples. The class distributions of emotions are then computed through the label distributions of each emotion to exclude ambiguity existing in distributions. Finally, those two distributions are adaptively fused according to the attention weights to train the target branch. Extensive experiments are conducted on three real-world datasets, RAF-DB, AffectNet and SFEW, where our Ada-DF shows advantages over the state-of-the-art works. The code is available at https://github.com/taylor-xy0827/Ada-DF.

Recently, vehicle platooning has demonstrated its potential for improving traffic efficiency and enhancing the driving experience. When the onboard sensors of follower vehicles are unavailable, the leader vehicle typically needs to maintain the safety of platooning system through vehicle-to-vehicle (V2V) communications. Increasing communication resource utilization, such as transmission power, can enhance communication accuracy and ensure platooning safety but induce more communication costs. Balancing communication costs and system safety poses challenges in this dynamic system. In this paper, we propose a joint optimization method for transmission power control and system stability maintenance based on deep reinforcement learning (DRL), which can minimize the total transmission power of the leader vehicle over a period of time while maintaining the stability of the platooning system. To achieve this, we implement two advanced DRL algorithms, namely Deep Q-Network (DQN) and Actor-Critic, to derive task-oriented power control strategies for platooning stability. Experimental results show that the proposed strategy outperforms the conventional power control strategy. The transmission power gradually increases as the follower vehicle approaches the boundary of the safe distance range, indicating that the proposed strategy can adaptively adjust the transmission power to meet the requirements of the task.

The recently proposed learned bloom filter (LBF) opens a new perspective on how to reconstruct bloom filters with machine learning. However, the LBF has a massive time cost and does not apply to multidimensional spatial data. In this paper, we propose a prefix‐based and adaptive learned bloom filter (PA‐LBF) for spatial data, which efficiently supports the insertion and deletion. The proposed PA‐LBF is divided into three parts: (1) the prefix‐based classification. The Z‐order space‐filling curve is used to extract data, prefix it, and classify it. (2) The adaptive learning process. The multiple independent adaptive sub‐LBFs are designed to train the suffixes of data, combined with part 1, to reduce the false positive rate (FPR), query, and learning process time consumption. (3) The backup filter uses CBF. Two kinds of backup CBF are constructed to meet the situation of different insertion and deletion frequencies. Experimental results prove the validity of the theory and show that the PA‐LBF reduces the FPR by 84.87%, 79.53%, and 43.01% with the same memory usage compared with the LBF on three real‐world spatial datasets. Moreover, the time consumption of PA‐LBF can be reduced to 5× and 2.05× that of the LBF on the query and learning process, respectively.

Gesture recognition based on radio frequency identification (RFID) has attracted much research attention in recent years. Most existing RFID-based gesture recognition approaches use signal profile matching to distinguish different gestures, which incur large recognition latency and fail to support real-time applications. In this paper, we design and implement ReActor, a real-time and accurate gesture recognition system that recognizes a user's gestures with low latency and high accuracy even when the gestures'speed varies. ReActor combines the time-domain statistical features and the frequency-domain features to precisely represent the signal profile corresponding to different gestures. To maintain high accuracy across different environments, we preprocess the signals to remove reflection signals from surrounding objects and use only the signals related to gestures to train the classifier. Moreover, we train a classifier to predict the speed of the gesture and feed the extracted features to different classifiers according to the speed. We implement ReActor and evaluate its performance in different scenarios. Experimental results show that ReActor achieves an average accuracy of 97.2% in recognizing 18 different gestures with an average latency of 72 ms, more than two orders of magnitude faster than approaches based on profile template matching.

Although deep learning methods have drastically improved the performance on visual recognition tasks in which large inter-class variances exist, similar-class recognition continues to pose significant challenges, mainly due to the close resemblance between similar classes. The challenge is further compounded in the case of few-shot learning because only a very small amount of training data is available; accordingly, a certain performance degradation has been observed when some few-shot methods are applied for classification tasks. To address the aforementioned issue, we propose a novel Relation Separation Network (RSNet) in this paper, aiming to boost few-shot learning by improving similar-class recognition performance. We assume that image features consist of common and private features, where the common features capture the basic attributes shared among similar classes and their private counterparts capture the unique attributes of each class. Our RSNet learns to decouple the common and private features of an image. As a result, the feature representation of an image is composed of two weakly associated but easily aligned components, and better classification performance is achieved by giving more attention to subtle features. Experimental results on the publicly available datasets miniImageNet, CUB, and CIFAR-FS show that the proposed model outperforms existing state-of-the-art methods. Specifically, compared to PT+MAP, RSNet improves the accuracy of classification on the CUB dataset by approximately 5% and that of similar-class classification by more than 10%.

Face images are typically a key component in the fields of security and criminal investigation. However, due to lighting and shooting angles, faces taken under low-light conditions are often difficult to recognize. Face super-resolution (FSR) technology can restore high-resolution faces based on low-resolution inputs. However, existing face super-resolution methods typically rely on prior knowledge of inaccurate faces estimated from low-resolution images. Faces restored by low-light inputs may suffer from problems such as low brightness and many missing details. In this article, we proposed an Illumination-Enhanced Face Super-Resolution (IEFSR) model that can progressively super-resolve low-light faces of 32 × 32 pixels by an upscaling factor of 8. While reconstructing the low-light low-resolution face into a clear and high-quality face, we introduce a coarse low-resolution (LR) restoration network to recover the LR face details hidden in the dark. In the generator, we use a series of style blocks with noise to make the generated faces appear to have a more realistic visual aesthetic. Additionally, we introduce spectrum normalization in the discriminator to improve training stability. Extensive experimental evaluations show that the proposed IEFSR yields visually and metrically more attractive results than existing state-of-the-art FSR methods.

Visual analytics techniques are widely utilized to facilitate the exploration of online educational data. To help researchers better understand the necessity and the efficiency of these techniques in online education, we systematically review related works of the past decade to provide a comprehensive view of the use of visualization in online education problems. We establish a taxonomy based on the analysis goal and classify the existing visual analytics techniques into four categories: learning behavior analysis, learning content analysis, analysis of interactions among students, and prediction and recommendation. The use of visual analytics techniques is summarized in each category to show their benefits in different analysis tasks. At last, we discuss the future research opportunities and challenges in the utilization of visual analytics techniques for online education.

Integrity and privacy are two important secure matrices in cyber security. Due to the limited resources and computing capability of the sensor nodes, it is challenging to simultaneously satisfy these two matrices for top-k querying in two-tiered sensor networks. To solve this problem, this paper proposes a weight-bind-based secure top-k query processing scheme (WBB-TQ), which utilises both the order-preserving symmetric encryption scheme (OPES) and the pairwise-key encryption technique to ensure data privacy in top-k querying. Since OPES can keep the size orders of the sensed data items unchanged before and after they are encrypted, the upper-layer storage nodes in the network can process top-k queries without knowing the exact values of the sensed data items. To guarantee the completeness of query results, we propose a novel method to establish chaining relationship among all the data items generated by each sensor node. By checking whether the relationship holds on not, Sink can find out whether adversaries drop and/or tamper with part or all of the qualified top-k data items in the query results. Theoretical analyses show that WBB-TQ can preserve data integrity and privacy of the top-k query results. Extensive simulation results further demonstrate that, WBB-TQ incurs very low computational and communication cost in securing top-k querying.

Cryptocurrencies represented by Bitcoin have fully demonstrated their advantages and great potential in payment and monetary systems during the last decade. The mining pool, which is considered the source of Bitcoin, is the cornerstone of market stability. The surveillance of the mining pool can help regulators effectively assess the overall health of Bitcoin and issues. However, the anonymity of mining-pool miners and the difficulty of analyzing large numbers of transactions limit in-depth analysis. It is also a challenge to achieve intuitive and comprehensive monitoring of multi-source heterogeneous data. In this study, we present SuPoolVisor, an interactive visual analytics system that supports surveillance of the mining pool and de-anonymization by visual reasoning. SuPoolVisor is divided into pool level and address level. At the pool level, we use a sorted stream graph to illustrate the evolution of computing power of pools over time, and glyphs are designed in two other views to demonstrate the influence scope of the mining pool and the migration of pool members. At the address level, we use a force-directed graph and a massive sequence view to present the dynamic address network in the mining pool. Particularly, these two views, together with the Radviz view, support an iterative visual reasoning process for de-anonymization of pool members and provide interactions for cross-view analysis and identity marking. Effectiveness and usability of SuPoolVisor are demonstrated using three cases, in which we cooperate closely with experts in this field.

Industrial networks are complex and diverse. Among existing intrusion prevention systems available, several of them have problems such as low detection accuracy rate, high false positive (FP) rate, and low real-time performance for impersonation attacks. To address such issues, it is proposed in this article an industrial network intrusion detection algorithm based on multifeature data clustering optimization model, where the weighted distances and security coefficients of data are classified based on the priority threshold of data attribute feature for each node in the network, given that the data modules in the industrial network environment are diverse and easy to diagnose, restore, and rebuild. The proposed algorithm can effectively improve the detection rate and real-time performance of detecting abnormal behavior for the multifeature data in industrial networks. The novel features are twofold, to rapidly select a node with high-security coefficient as the cluster center, and match the multifeature data around the center into a cluster. Experimental results show that the proposed algorithm has good superiority in terms of detection rate and time compared to other algorithms. In the industrial network, the detection accuracy of abnormal data reaches 97.8%, and the FP of detection is decreased by 8.8%.

Traditional radio monitoring and management largely depend on radio spectrum data analysis, which requires considerable domain experience and heavy cognition effort and frequently results in incorrect signal judgment and incomprehensive situation awareness. Faced with increasingly complicated electromagnetic environments, radio supervisors urgently need additional data sources and advanced analytical technologies to enhance their situation awareness ability. This paper introduces a visual analytics approach for electromagnetic situation awareness. Guided by a detailed scenario and requirement analysis, we first propose a signal clustering method to process radio signal data and a situation assessment model to obtain qualitative and quantitative descriptions of the electromagnetic situations. We then design a two-module interface with a set of visualization views and interactions to help radio supervisors perceive and understand the electromagnetic situations by a joint analysis of radio signal data and radio spectrum data. Evaluations on real-world data sets and an interview with actual users demonstrate the effectiveness of our prototype system. Finally, we discuss the limitations of the proposed approach and provide future work directions.

The television ratings provide an effective way to analyze the popularity of TV programs and audiences’ watching habits. Most previous studies have analyzed the ratings from a single perspective. Few efforts have integrated analysis from different perspectives and explored the reasons for changes in ratings. In this paper, we design a visual analysis system called TVseer to analyze audience ratings from three perspectives: TV channels, TV programs, and audiences. The system can help users explore the factors that affect ratings, and assist them in decisions about program productions and schedules. There are six linked views in TVseer: the channel ratings view and program ratings view show ratings change information from the perspective of TV channels and programs respectively; the overlapping program competition view and the same-type program competition view indicate the competitive relationships among programs; the audience transfer view shows how audiences are moving among different channels; the audience group view displays audience groups based on their watching behavior. Besides, we also construct case studies and expert interviews to prove our system is useful and effective.

Contactless gesture recognition has emerged as a promising technique to enable diverse smart applications, e.g., novel human-machine interaction. Among others, gesture recognition based on radio frequency identification (RFID) is preferred due to its prevalent availability, low cost, and ease in deployment. However, current RFID-based gesture recognition approaches usually use profile template matching to distinguish different gestures, making them suffer from large recognition latency and fail to support real-time applications. In this paper, we propose a real-time and accurate contactless RFID-based gesture recognition approach called ReActor. ReActor uses machine learning rather than time-consuming profile template matching to distinguish different gestures, and thus achieves both very low recognition latency and high recognition accuracy. The major challenge of our approach is to determine a set of suitable attributes that can preserve the profile features of the signals related to different gestures. We combine two types of attributes in ReActor: the statistics of the signal profile that characterize coarse-grained features and the wavelet (transformation) coefficients of the signal profile that characterize fine-grained local features, both of which can be calculated fast. Experimental results demonstrate that ReActor can recognize a gesture with average latency less than 51ms, two orders of magnitude faster than state-of-the-art approaches based on profile template matching. Furthermore, ReActor also achieves higher recognition accuracy than previous works due to its optimized attribute set.

Radio frequency identification (RFID)-based localization and activity recognition have attracted much research attention recently. They rely on accurate measurements of signal features, e.g., phase and received signal strength (RSS), in line-of-sight (LOS) condition to estimate the location or activity status of the target objects. However, the LOS requirement might be frequently breached by obstacles between reader and tags in real deployed RFID systems. The resulting non-LOS (NLOS) signal will greatly reduce localization or activity recognition accuracy. How to filter out NLOS in the localization/activity recognition process is therefore practically important for guaranteeing accuracy. In this paper, we propose the first LOS/NLOS path recognition approach to differentiate the signals by LOS path from the ones by NLOS path. The proposed approach is both precise (with precision higher than 0.95) and real-time in nature (with recognition delay less than 400 ms) due to the following innovative designs. First, we design a new metric that can precisely distinguish LOS and NLOS paths by considering the joint variance of phase and RSS. Second, we propose an efficient method to mitigate the negative impacts of phase ambiguity on recognition precision. Third, we sample over a selected subset of channels and use only a handful of readings to perform LOS/NLOS path recognition, which greatly reduces the recognition delay without sacrificing precision. We conducted extensive experiments with commercial-off-the-shelf RFID devices. The results show that our approach achieves high precision and recall in all testing cases, with a precision of up to 0.969 and a recall of up to 0.991. Furthermore, our approach can also distinguish between different types of obstacles with an accuracy as high as 0.93.

Targeting for providing communication services in the Intermittently Connected Vehicular Networks (ICVN) where there are no end-to-end communication and routing paths between vehicles, many relaying algorithms and routing protocol have been proposed under the assumption that vehicular nodes in the network are homogeneously distributed in the network with the same contact rate and delivery cost. However, experimental data has found the heterogeneous mobility behaviors with vehicles, and various applications of vehicular networks show that the vehicular nodes belong to different types on the aspects communication ability, mobility behaviors, etc. By utilizing these heterogeneous features to enhance the network performance, we investigate the issue of optinal relay selection schemes for ICVN consisting of heterogeneous vehicular nodes. We investigate both the case of in contact relaying and off contact relaying. In each relaying scenario, we select relay vehicles to optimize in reducing the message transmission cost at the same time satisfying the needed transmission ratio considering both the heterogeneous contact rates and transmission cost. Realistic trace driven simulations demonstrate the effective of the designed relaying schemes in various settings and realistic environment.

Traffic congestions become an increasingly important issue influencing people's daily life, and the development of vehicular networks seen to be a significant technology to solve the problem of traffic congestion. In order to solve this problem by vehicular networks and intelligent transportation system, vehicular mobility is an important role in the network and system design. However, it is a still unsolved problem that is there any regularity existed in the daily random vehicular mobility. In this paper, we study the regularity that characterizes the vehicular mobility in large-scale urban environment. Despite the mess the vehicular traces appear to look like, we find certain location patterns across the whole datasets, which imply high potential predictability in vehicle location.

In disruption tolerant networks, gossip is an efficient routing scheme, which significantly reduces the message delivery overhead while maintaining a relatively high delivery rate. This mechanism needs network nodes to forward messages and data according to the system-defined gossip probability in a selfless and cooperative way. In this paper, we investigate how node selfishness influences the performance of energy-constrained gossip. By modeling the data transmission process with selfish behaviors in the gossip using a two-dimensional continuous time model of Markov chain, we derive closed-form formulae for average data delivery delay and cost. Extensive numerical results show that gossip is robust enough to selfish behaviors since even when they increase the data delivery delay, there is a gain on the data transmission cost. Moreover, we analyze tradeoffs among the gossip probability, selfishness and energy constraint on the system performance.

Data gathering is one of the most basic applications of wireless sensor networks. How to effectively preserve the energy of the nodes in order to extend the network lifetime is a challenging problem in data gathering. Currently, many researches focus on constructing a virtual backbone of the network by using minimum connected dominating sets. Each node in the network can transmit its data to the sink by the virtual backbone. However, the minimum connected dominating sets may result in unbalanced energy consumption among nodes, which shortens lifetime of the network and consequently limits their application in many fields. In this paper, we propose an energy-balanced connected dominating set distributed scheme (DGA-EBCDS) which prolongs the network lifetime by constructing an energy-balanced connected dominating set for data gathering. When constructing the virtual backbone in DGA-EBCDS, we prioritize selecting those nodes with higher energy and larger degree. This makes the energy consumption among nodes more balanced. Furthermore, the routing decision in DGA-EBCDS considers both the path length and the remaining energy of nodes on the path. This further prolongs the lifetime of nodes in the backbone and hence extends the lifetime of the whole network. We theoretically analyze the DGA-EBCDS algorithm and conduct extensive simulations to evaluate its performance. Simulation results show that DGA-EBCDS outperforms mr-CDS by prolonging the network lifetime by more than 50 percent.

Data gathering is one basic functional operation provided by wireless sensor networks. Most existing clustering protocols suffer from unbalanced energy consumption among nodes, which shortens the lifetime of the network and limits their application in many fields. In this paper, an energy-balanced dominating set based clustering scheme (EBDSC) is proposed to prolong the network lifetime by balancing energy consumption among nodes. In EBDSC, each node calculates the number of potential data gathering rounds it can afford when it acts as a cluster head. The node that can afford most rounds among its neighbors becomes a candidate cluster head. A normal node that is not a candidate head calculates the average number of candidate cluster heads that cover it and broadcasts the value. A candidate head finds the median of the values received from its neighboring normal nodes, and becomes a final cluster head with a probability inversely proportional to the median. Extensive simulations are conducted to compare the performance of EDBSC and a previous work ECDS. The results show that EBDSC outperforms ECDS by prolonging the network lifetime by at most 51.4% as well as guaranteeing full network coverage.