JunShuo Zhang, Chengrui Huang, Feng Guo, Zihan Li, Ke Shi, Menghua Jiang, Jiguo Yu, Shuo Shang, Shen Gao. Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers). 2026.

With the rapid advancement of technology, mobile crowdsensing (MCS) has become a key enabler of improved daily life, drawing on its unique advantages. However, MCS systems face significant challenges concerning location privacy leakage, particularly during task allocation. To address the risk of worker location privacy leakage, we propose a location privacy-preserving system for crowdsensing based on secure sorting (LPPCS). LPPCS integrates elliptic curve cryptography (ECC) and secure multi-party computation (SMPC) technologies. By sorting the actual distances between workers and task locations, it achieves precise task assignment while ensuring the confidentiality and integrity of workers’ location data. The system consists of two main parts. The first part introduces a reverse sealed-bid auction mechanism, which reduces the computational costs by scaling down the number of workers participating in subsequent encryption computations. The second part designs a secure sorting protocolSSP. This protocol ensures that each worker only learns the relative sorting of their true distance to the task location and uploads this information to the server for final task assignment. Crucially, workers cannot access information about one another. This not only effectively protects their location privacy but also improves the accuracy of task assignments—all without the need for a trusted server. Finally, we conducted comprehensive evaluations using both simulated and real-world datasets. The results show that LPPCS performs exceptionally well in reducing computational costs, protecting workers’ location privacy, and improving task allocation precision.

Federated learning is a distributed machine learning paradigm through centralized model aggregation. However, standard federated learning relies on a centralized server, making it vulnerable to server failures. While existing solutions utilize blockchain technology to implement Decentralized Federated Learning (DFL), the statistical heterogeneity of data distributions among clients severely degrades the performance of DFL. Driven by this issue, this paper proposes a decentralized federated prototype learning framework, named DFPL, which significantly improves the performance of DFL under heterogeneous data distributions. Specifically, DFPL introduces prototype learning into DFL to mitigate the impact of statistical heterogeneity and reduces the amount of parameters exchanged between clients. Additionally, blockchain is embedded into our framework, enabling the training and mining processes to be executed locally on each client. From a theoretical perspective, we analyze the convergence of DFPL by modeling the required computational resources during both training and mining. The experiment results highlight the superiority of DFPL in both model performance and communication efficiency across four benchmark datasets with heterogeneous data distributions.

Existing one-time dehazing approaches struggle to simultaneously restore high-fidelity scene content and suppress haze-induced artifacts. Although recursive iterations can enhance the modeling capacity for complex degradations, the associated estimation errors are often amplified during propagation, thereby constraining the overall dehazing performance. To address these challenges, this work proposes a deep unfolding dehazing network, termed I3-Net, which integrates an iterative refinement strategy (IRS) and self-prompted correction learning (SCL). Specifically, we first develop a baseline dehazing network, termed I-Net, which is constructed around a physically-aware feature enhancement module (PFEM). By embedding physical priors into the feature space, PFEM enforces consistency between learned representations and the haze degradation process, thereby providing a reliable foundation for subsequent refinement. Building upon I-Net, IRS is designed to recursively unfold the baseline, progressively improving its dehazing outputs and enabling the construction of a deep unfolding dehazing network, I3-Net, with cross-stage feature association capability. To mitigate the accumulation of minor estimation errors inherent in iterative frameworks, we further propose SCL mechanism inspired by the corrective behavior of the human visual system. By integrating IRS and SCL, I3-Net adaptively identifies and rectifies residual haze regions at each unfolding stage, effectively suppressing error propagation and achieving high-quality image restoration. Extensive experiments demonstrate that the proposed I3-Net consistently outperforms existing SOTA methods in both quantitative metrics and visual perception across multiple benchmark datasets.

This paper investigates one of the most challenging problems in single image dehazing: how to restore haze-free scenes solely from the input observed image without relying on paired or unpaired images and how to extract useful prior information from the observed image to guide the dehazing process. To address these challenges, this paper introduces a novel zero-reference real-world image dehazing method via deep self-decoupling and reverse knowledge transfer (ZRID-Net). Specifically, we first employ a model-driven approach to preliminarily decouple the observed image into coarse-grained components: the haze-free image, transmission map, and atmospheric light. Subsequently, we refine the haze-free image and transmission map separately via a data-driven approach. In addition, we propose a novel reverse knowledge transfer method to exploit latent prior information within hazy images thoroughly for dehazing guidance. This method combines knowledge transfer and contrastive learning to reverse guide the refinement network away from haze characteristics. Finally, a perceptual fusion strategy is employed to obtain haze-free images with high visibility and realism. Extensive experiments demonstrate that the proposed ZRID-Net effectively restores image clarity, enhances structural details, and improves color fidelity across various challenging haze conditions without relying on paired or unpaired supervision. On multiple benchmark datasets, ZRID-Net outperforms existing SOTA approaches in terms of both quantitative metrics and visual quality. The results also confirm its strong generalizability and practical applicability to real-world scenarios. The relevant implementation code can be found at https://github.com/cswangshilong/ZRID-Net.

Federated learning (FL), a distributed computing paradigm, is vulnerable to poisoning attacks that impair model performance and privacy attacks that leak participant information. Existing FL defense schemes struggle to counter poisoning attacks under data heterogeneity and high privacy computation overhead, limiting the practicality of federated learning. To address these issues, this paper proposes a model-contrastive federated learning framework with lightweight privacy preservation and poisoning attack detection, named MCFL. Specifically, we design a novel model-contrastive term by aligning intermediate-layer representations of models in the local optimization function to promote consistency of model updates among benign participants. Additionally, we design a secure aggregation protocol that adopts two-server aggregation instead of the single server to resist poisoning attacks with lightweight privacy protection. The proposed MCFL is theoretically proven in terms of convergence, robustness, and privacy. Extensive experiments demonstrate the superiority of MCFL compared to existing FL defense schemes.

Temporal knowledge graph (TKG) extrapolation aims to predict future, previously unseen events based on historical facts. However, most existing temporal knowledge graph extrapolation methods either focus on global cyclic regularities or on local adjacent transitions. These methods overlook the multi-granularity nature of temporal signals and often rely on heuristic fusion schemes that are sensitive to noise. To address these limitations, we propose MTRM, a Multi-granularity Trend Retrieval and Modeling framework for TKG extrapolation. Specifically, we first apply semantic clustering to retrieve a compact set of long-term trend clusters from sequences of historical subgraphs, capturing enduring interaction patterns. Then, we introduce a trend-aware attention-enhancing evolution module with an auxiliary contrastive loss to learn fine-grained short-term dynamics by aligning each hidden state with its subsequent subgraph. To integrate information at different granularities, we design a multi-granularity attention layer that adaptively fuses the long-term clusters with the short-term trend states for each query entity. Additionally, an inter-granularity contrastive objective is employed to align these representations and enhance robustness to noisy snapshots. Experiments on four benchmark datasets demonstrate that MTRM outperforms state-of-the-art baselines by up to 5.89% in mean reciprocal rank (MRR), indicating improved robustness on large-scale noisy event streams. Moreover, MTRM provides interpretable insights into how long- and short-term temporal granularities jointly drive future-event prediction.

Mobile Edge CrowdSensing (MECS) based on Federated Learning (FL) has attracted widespread attention as an intelligent data collection and processing approach. FL trains the global model through aggregating local models of participants without requiring the exchange of raw data. However, directly sharing local models is vulnerable to backdoor attacks launched by adversaries. What's worse, malicious server may collude with participants to manipulate the parameter updating of models and even compromise the accuracy of whole system. To address these challenges, this paper proposes a Privacy-Enhanced Federated Learning (PEFL) framework for MECS with the aim of resisting both backdoor and collusion attacks. In PEFL, a Backdoor Resistant Privacy-Enhanced Aggregation (BRPEA) mechanism with the Differential Privacy-Enhanced Exponential (DPEE) method is developed to perturb local models of participants. Clustering and clipping techniques are also designed in BRPEA to effectively distinguish backdoor models from the benign local models, which eliminate the influence of local models deviation and optimize the noise introduced by differential privacy. Furthermore, a Collusion Resistant Privacy-Preserving Aggregation (CRPEA) mechanism is studied. CRPEA can avoid the collusion between servers and participants and prevent the privacy of local models from being leaked. The theoretical analysis proves the security of proposed PEFL framework and the simulation experiments demonstrate that PEFL can not only ensure the aggregation accuracy of encrypted models but provide robustness against both backdoor and collusion attacks.

As a combination of digital twin and edge computing, the digital twin edge networks (DITENs) have gained significant interest due to their bridging roles between physical edge networks and digital systems. The Device-to-Device (D2D) communication acts as an ongoing transmission paradigm for DITENs since it facilitates interoperability between nearby wireless entities and enhances the spectrum utilization and overall throughput via direct link. However, most existing works on the D2D communication are related to the centralized ones, and consider the mobility and interference management separately, which cannot be used for the dynamic scenarios in DITENs. In this paper, we consider the D2D communication problem in dynamic DITENs in the context of the SINR model, and propose a dynamicity-tolerant D2D communication algorithm in a distributed manner. Using an oblivious transmission strategy, our algorithm can complete the D2D communication among$n$entities within$O(\log n)$time steps despite the various dynamic factors, which achieves asymptotically optimal time complexity. It is asserted that the D2D communication algorithm is asymptotically optimal, given that the lower bound for successful message dissemination is$\Omega (\log n)$. Rigorous theoretical analyses and empirical results are conducted to show the correctness and efficiency of our proposed algorithm.

The rapid proliferation of the Internet of Things (IoT) has made resource exchange and collaboration across diverse IoT domains commonplace, necessitating secure and privacy-preserving cross-domain authentication. However, existing schemes suffer from critical limitations: they lack time-bound access control, leading to persistent unauthorized access and heightened security risks, and most are incomplete, requiring resource-intensive redeployment of cryptographic mechanisms and increasing management overhead. To address these challenges, we propose a dynamic time-bound anonymous complete cross-domain authentication scheme that leverages consortium blockchain for decentralized trust, embeds dual temporal constraints, expiration time and permissible authentication periods, into credentials for fine-grained access control and automatic natural revocation, and employs accumulators and non-interactive zero-knowledge proofs (NIZKs) to enable anonymous authentication while ensuring strong privacy protection. Crucially, the proposed scheme achieves complete cross-domain authentication without modifying existing cryptographic mechanisms, significantly reducing overhead in computational, communication, and storage. Security and performance analyses confirm that the proposed scheme not only guarantees robust security and privacy but also outperforms existing schemes in efficiency.

The widespread adoption of data-driven services, including networked data collection and analysis systems, has greatly enhanced convenience and decision-making, but it has also raised growing concerns about the trade-off between fine-grained utility and personalized privacy guarantees. Personalized Differential Privacy (PDP) offers a flexible framework by allowing users to specify individualized privacy budgets. However, existing sampling-based PDP mechanisms often rely on coarse risk modeling assumptions that treat individual data characteristics uniformly, leading to suboptimal utility and inefficient privacy expenditure. In this paper, we propose the Utility-Aware Sampling Mechanism (UASM), a principled PDP implementation that enables fine-grained, user-centric privacy control while explicitly optimizing utility. First, UASM formalizes policy-assisted secret specifications, allowing confidentiality to be determined through a combination of baseline protection rules and personalized privacy preferences, and combines them with individualized privacy budgets. Second, UASM employs a two-stage utility-aware sampling strategy to calibrate noise: (i) an optimal global threshold selected to reduce unnecessary privacy-budget wastage while respecting users’ declared budgets, and (ii) a sensitivity-aware refinement stage that allocates privacy loss according to each record’s influence on query accuracy. Formal privacy analysis demonstrates that UASM provides rigorous privacy guarantees and promotes fairer privacy expenditure under heterogeneous privacy requirements. Extensive experiments on synthetic and real-world datasets, including network-oriented downstream tasks, show that UASM achieves a superior privacy-utility trade-off over state-of-the-art PDP baselines, underscoring its practical effectiveness.

The exponential growth of wearable medical devices (WMDs) and the increasing demand for real-time health data sharing necessitate secure and fine-grained access control mechanisms. However, existing ciphertext-policy attribute-based encryption (CP-ABE) schemes suffer from computational and storage overheads that grow linearly with policy complexity. To address this challenge, we propose fog-assisted composite attribute-based encryption (FA-CABE), a novel scheme that integrates composite attributes with fog computing to enhance efficiency. FA-CABE leverages the subset sum problem (SSP) to map conjunctive policy clauses to composite attributes, substantially reducing both encryption and decryption overhead. A dualfog-node architecture offloads cryptographic computations from WMDs, enabling lightweight local processing. Rigorous security analysis under the Decisional Bilinear Diffie-Hellman (DBDH) assumption demonstrates that FA-CABE achieves replayable chosen ciphertext attack (RCCA) security. Experimental results show that FA-CABE achieves encryption speeds that are 22.13×–145.02× faster and decryption speeds that are 6.71×–161.83× faster than existing schemes, while requiring only a constant number of operations for decryption. Additionally, experimental validation on the Raspberry Pi 4B shows that the energy consumption is as low as 0.72 W per core, with data processing speed reaching 23.38 MB/s.

The linkschedulingis to determine which links should be scheduled at what times, each of which is a (sender, receiver) communication pair used to realize wireless transmission of a message. It is an appealing solution to fulfill the resource-constrained and latency requirements of unmanned aerial vehicle (UAV) swarms. However, most existing link scheduling algorithms primarily focus on the throughput or latency in wireless communication, neglecting the protection against the eavesdropping attack due to the openness of UAV swarms, thereby leading to unsafe message dissemination. To address this issue, we consider integrating the covert communication into the link scheduling by concealing the very existence of message transmission. We first present a successive interference cancellation-based link diversity partition (SIC-LDP) algorithm in the context of the physical interference model, to maximize the number of concurrently transmitting links in a single time round, also called the maximum link scheduling (MLS) issue. Then, using a friendly jammer, we further propose a covertness-aware SIC-LDP algorithm (named SIC-CLDP) to resolve the MLS, as well as to defend against the eavesdropping attack. Both SIC-LDP and SIC-CLDP algorithms are proven to have constant approximation ratios. Next, implementing SIC-LDP and SIC-CLDP repeatedly can minimize the number of time rounds schedulingnparticipating links, termed the shortest link scheduling (SLS) issue, with an approximation ratio ofO(lnn). Lastly, theoretical proofs and simulation results demonstrate the correctness, covertness, and efficiency of our proposed algorithms under the eavesdropping attack.

In the era of pervasive online social networks (OSNs), the erosion of information privacy is occurring at an unprecedented rate. Empowering individuals with user-centric control over their private information is crucial to fostering public confidence in OSN services. Hence, the investigation into the personalized privacy configurations within the framework of differential privacy for OSNs, particularly for social relationships, is captivating. In this paper, we introduce a Collaborative Personalized Edge Differential Privacy model (CPEDP), ensuring personalized protection for sensitive social relationships while retaining the high utility of network features. Specifically, CPEDP allows each user to define a policy specification consisting of two complementary components: secret specifications at the edge level to identify sensitive relationships, and privacy specifications at the user level to determine personalized privacy parameters. These user-defined preferences are integrated through a collaborative privacy decision-making process that ensures consistent and interpretable privacy guarantees. Furthermore, we formalize the privacy primitive of CPEDP and develop a sampling-based mechanism to effectively implement the proposed model. Finally, comparative experiments on real-world datasets confirm that CPEDP achieves superior privacy-utility trade-offs, yielding more accurate estimates of key graph statistics through policy-driven personalization.

The vigorous development of the Industrial Internet of Things (IIoT) has brought massive amounts of data. In order to serve users more extensively and fully utilize the potential of data, it is particularly important to establish a fair and open IIoT data market. In order to enhance trust between data owners and consumers and facilitate transactions between the two parties, this article proposes a blockchain-based IIoT data market framework. To address another important issue in the IIoT data market: data pricing, we formulate the problem of maximizing the interests of the data platform, data providers, and consumers as a Stackelberg game pricing model. In this model, the data platform charges the data provider for data transmission, the data provider sells data to the consumer, and the consumer can determine the amount of data to purchase. The existence of Stackelberg equilibrium is proved by backward induction. Finally, the performance of the model was evaluated through numerical simulations.

Owing to the easy deployment and mobile flexibility, Unmanned Aerial Vehicle (UAV) assisted Mobile Edge Computing (MEC) has been deemed as one potential technology for handling the computation-intensive tasks at terminal devices (TDs). In this work, a MEC architecture assisted by UAVs is designed which achieves efficient offloading, computing, and downloading for tasks from multiple TDs via aerial to aerial collaboration of two UAVs. In this architecture, the task offloading process contains two parts, i.e., the offloading from TDs to a mobile UAV which flies around TDs, and the offloading from the mobile UAV to a hovering UAV which hovers in the air. The computing tasks from TDs will be divided into three parts allocated to the TDs themselves, and both two UAVs. Upon completion of computation, the computation results are downloaded to the TDs. The optimization objective is to seek for an optimal task division strategy to attain the weighted total energy consumption minimization for all devices. Since the formulated optimization problem is not convex, we develop a two-step iteration algorithm which jointly optimizes computing frequency, task allocation volume, as well as UAV's trajectory based on the method of block coordinate descent. Simulation results confirm the effectiveness and performance advantages of the designed algorithm.

In Internet of Things(IoT) systems, ensuring the secure exchange of information between devices from different domains is crucial. Current cross-domain authentication schemes based on a single blockchain struggle to meet the confidentiality requirements for data and information exchange in large-scale IoT systems. This paper proposes a blockchain-based identity authentication scheme (BCPPAS) for IoT, featuring dual-chain collaboration, and designs a novel certificateless aggregate signature algorithm to address complex certificate management and key escrow issues. The edge server is capable of aggregating different signatures to achieve batch authentication, markedly improving authentication efficiency and reducing computational and storage overhead. Also, BCPPAS is designed to avoid costly bilinear pairing operations, providing less computational overhead for IoT devices with limited resources. To protect the privacy of IoT devices, BCPPAS uses the pseudonym instead of the real identity. Finally, efficiency of BCPPAS are demonstrated through theoretical analysis and experiments.

The Internet of Things (IoT) connects numerous de-vices and sensors, generating data with significant informational and economic value. However, data silos hinder effective data utilization and trading, leading to the dispersion of data across various devices and systems. Additionally, traditional third-party trading models face challenges related to data security and trust. To address these issues, this paper proposes a secure data trading framework based on a consortium blockchain and designs a corresponding solution. Specifically, it introduces the integration of zero-knowledge proofs into the smart contract scheme for authenticity and integrity verification of transaction data. From the perspective of IoT device users, this paper aims to enable secure data trading through a decentralized platform, using off-chain storage methods to reduce the blockchain's data burden while ensuring security and privacy. Off-chain storage encrypts and securely stores sensitive data, recording only necessary information on the blockchain, effectively protecting user privacy. To validate the practicality of the proposed solution, experiments were conducted using Hyperledger Fabric, demonstrating its feasibility in facilitating secure storage and trustworthy trading of IoT data. Finally, this study analyzes the experimental results and offers valuable insights for future research.

The growing demand for large-scale training data in deep learning has promoted the use of open data collection, thereby increasing the risk of data poisoning attacks. Clean-label data poisoning attacks aim to compromise models by injecting malicious samples into the training set, while being constrained to maintain consistency between the visual features of the samples and their assigned labels. Though this constraint enhances attack feasibility in real-world settings, it also introduces significant technical challenges, such as reliance on white-box assumptions and limitations in stealth and effectiveness. To address these limitations, this paper proposes a novel clean-label data poisoning attack scheme based on representation-conditioned data generation (CPRCG). The scheme identifies "natural poisoned data" from open datasets, extracts their deep representations as constraints, and generates numerous new samples using the conditional data generation model MAsked Generative Encoder (MAGE). These samples preserve core similarities while introducing random variations in form and behavior. Experimental results show that samples generated by CPRCG achieve high stealth and diversity, outperforming MetaPoison by 4.1% in centralized learning and approaching the effectiveness of dirty-label attacks in federated learning.

The awareness of data privacy preservation in the Internet of Things (IoT) environment and the amount of IoT data production, are growing almost in parallel with each other. As a privacy-preserving framework, Federated Learning (FL) allows many participants to collaboratively build machine learning models while ensuring that their raw data remains local and undisclosed. However, as the devices charged in data collection are deployed in different IoT environments, we also face a significant challenge i.e., dealing with non-independently and identically distributed (non-IID) data. If the data is not distributed uniformly among the participants, it may lead to a significant performance degradation of the generated global model, which is far from the case when the data is distributed uniformly. To address this challenge, this study innovatively designs the Enhancing Federated Learning algorithm with Client-Specific Data Augmentation (FedSDA). The FedSDA matches clients by servers, and clients train local models using augmented datasets to overcome the negative influence mainly caused by non-IID, which consequently enhances the model accuracy. Our simulation experiments on the datasets Fashion-MNIST and CIFAR-10 ultimately demonstrate that FedSDA outperforms contemporary state-of-the-art FL strategies with similar design characteristics.

The combination of blockchain and Internet of Things technology has made significant progress in smart agriculture, which provides substantial support for data sharing and data privacy protection. Nevertheless, achieving efficient interactivity and privacy protection of agricultural data remains a crucial issues. To address the above problems, we propose a blockchain-assisted federated learning-driven support vector machine (BAFL-SVM) framework to realize efficient data sharing and privacy protection. The BAFL-SVM is composed of the FedSVM-RiceCare module and the FedPrivChain module. Specifically, in FedSVM-RiceCare, we utilize federated learning and SVM to train the model, improving the accuracy of the experiment. Then, in FedPrivChain, we adopt homomorphic encryption and a secret-sharing scheme to encrypt the local model parameters and upload them. Finally, we conduct a large number of experiments on a real-world dataset of rice pests and diseases, and the experimental results show that our framework not only guarantees the secure sharing of data but also achieves a higher recognition accuracy compared with other schemes.

In the Internet of Things (IoT), a large number of devices are connected using a variety of communication technologies to ensure that they can communicate both physically and over the network. However, devices face the challenge of a single point of failure, a malicious user may forge device identity to gain access and jeopardize system security. In addition, devices collect and transmit sensitive data, and the data can be accessed or stolen by unauthorized user, leading to privacy breaches, which posed a significant risk to both the confidentiality of user information and the protection of device integrity. Therefore, in order to solve the above problems and realize the secure transmission of data, this paper proposed EBIAS, a secure and efficient blockchain-based identity authentication scheme designed for IoT devices. First, EBIAS combined the Elliptic Curve Cryptography (ECC) algorithm and the SHA-256 algorithm to achieve encrypted communication of the sensitive data. Second, EBIAS integrated blockchain to tackle the single point of failure and ensure the integrity of the sensitive data. Finally, we performed security analysis and conducted sufficient experiment. The analysis and experimental results demonstrate that EBIAS has certain improvements on security and performance compared with the previous schemes, which further proves the feasibility and effectiveness of EBIAS.

With the growth of the Internet of Things (IoT), millions of users, devices, and applications compose a complex and heterogeneous network, which increases the complexity of digital identity management. Traditional centralized digital identity management systems (DIMS) confront single points of failure and privacy leakages. The emergence of blockchain technology presents an opportunity for DIMS to handle the single point of failure problem associated with centralized architectures. However, the transparency inherent in blockchain technology still exposes DIMS to privacy leakages. In this paper, we propose the privacy-protected IoT DIMS (PPID), a novel blockchain-based distributed identity system to protect the privacy of on-chain identity data. The PPID achieves the unlinkability of identity-credential-verification. Specifically, the PPID adopts the Zero Knowledge Proof (ZKP) algorithm and Shamir secret sharing (SSS) to safeguard privacy security, resist replay attacks, and ensure data integrity. Finally, we evaluate the performance of ZKP computation in PPID, as well as the transaction fees of smart contract on the Ethereum blockchain.

In this paper, we propose an innovative pricing mechanism for cloud-edge collaborative computing resources that combines Stackelberg differential games with combinatorial double auction. The scenario of trading heterogeneous computing resources between cloud data centers, edge servers and users is modeled as a two-stage game. The Stackelberg game equilibrium is solved by Hamilton-Jacobi-Bellman (HJB) equation to optimize the resource allocation and pricing between data centers and edge servers. Markov game with multi-agent reinforcement learning is used to ensure the optimal bidding strategy of users, while differential privacy mechanism is introduced to protect participants’ sensitive information. Experimental results show that the edge server utility is improved by at least 50% and the user utility by 30% compared to the baseline algorithm. The mechanism accelerates the convergence of the game process while protecting the privacy of auction participants, providing a novel and efficient solution to the resource allocation challenge in dynamic computing environments.

As the Industrial Internet of Things (IIoT) expands, the number of stakeholders increases. Many entities require significant amounts of data from industrial devices. These data streams improve information sharing and optimize the industrial chain. However, IIoT’s enormous data volumes pose challenges to traditional encryption methods, which are unable to meet efficiency and energy consumption requirements. Thus, a new, efficient encryption algorithm is essential for managing data flows among IIoT subscribers. In this paper, we propose a fast, low-energy, high-security encryption scheme to manage multi-entity data streams. First, we introduce a novel encryption scheme based on the Subset Sum Problem (SSP), which improves energy efficiency and speed. Second, to meet subscription requirements, we employ attribute-based encryption (ABE) for key forwarding. Finally, we handle subscription revocations with device key updates. The device owner utilizes their secret value to generate an identity proof with a key update request.

Differential privacy is widely employed in decentralized learning to safeguard sensitive data by introducing noise into model updates. However, existing approaches that use fixed-variance noise often degrade model performance and reduce training efficiency. To address these limitations, we propose a novel approach called decentralized learning with adaptive differential privacy via variance-reduced stochastic gradient push (ADP-VRSGP). This method dynamically adjusts both the noise variance and the learning rate using a stepwise-decaying schedule, which accelerates training and enhances final model performance while providing node-level personalized privacy guarantees. To counteract the slowed convergence caused by large-variance noise in early iterations, we introduce a progressive gradient fusion strategy that leverages historical gradients. Furthermore, ADP-VRSGP incorporates decentralized push-sum and aggregation techniques, making it particularly suitable for time-varying communication topologies. Through rigorous theoretical analysis, we demonstrate that ADP-VRSGP achieves robust convergence with an appropriate learning rate, significantly improving training stability and speed. Experimental results validate that our method outperforms existing baselines across multiple scenarios, highlighting its efficacy in addressing the challenges of privacy-preserving decentralized learning.

Smart healthcare leverages Internet of Things (IoT), wireless communication and cloud computing technologies in the medical industry to enable healthcare professionals and patients to deliver remote medical services, conduct intelligent monitoring and analyze diseases without being constrained by time and location. Wireless Body Area Network (WBAN), extensively utilized in this sector, is a wireless network composed of wearable or embedded devices placed in different parts of the human body to monitor and record human health signals continuously. However, a contradiction exists between identity authentication and privacy protection in WBANs, which necessitates addressing the challenge of balancing anonymity and traceability. The open wireless environment makes WBANs vulnerable to various attacks and security threats, while sensor nodes in these networks face limitations such as restricted computing power. This paper addresses practical concerns in WBANs including identity authentication and dynamic user management, and develops an effective privacy-preserving authentication scheme that incorporates revocability and conditional privacy protection. A novel revocable certificateless short signature algorithm is designed that not only has high execution efficiency but also utilizes the binary tree structure to achieve keys update and user revocation, ensuring high execution efficiency while addressing the issue of high key management complexity in traditional schemes. This scheme uses pseudonyms instead of real identity information in authentication request messages for anonymity, and tracks malicious users based on the (t, k) secret sharing mechanism. The papers security analysis shows that the scheme is unforgeable under the random oracle model (ROM) and can resist typical security threats meeting various security requirements. Compared with other related schemes, this scheme has higher communication and computational efficiency and is more suitable for WBAN environments.

Cloud-fog automation architecture has propelled the advancement of the Industrial Internet of Things (IIoT), significantly enhancing production efficiency and intelligence through extensive data collection and connectivity. Simultaneously, industrial cyber-physical system leverages this data to achieve intelligent control and optimization of production processes. As industrial production becomes increasingly specialized and complex, independent operations within a single domain are no longer sufficient to meet demands, making cross-domain collaborative production inevitable. Consequently, ensuring the security of cross-domain communication and data sharing has become a critical issue for IIoT under the cloud-fog automation architecture. Existing solutions encounter substantial management and computational burdens in cross-domain communication and data sharing, and they are vulnerable to privacy leakage risks. To address these challenges and enhance industrial production efficiency, this paper uses consortium blockchain to co-design a cross-domain authentication and data sharing scheme. The scheme ensures secure and private cross-domain communications with minimal computational, communication, and storage overhead. And, the proposed time-specific plaintext checkable encryption protocol can secure data during cross-domain sharing. Security and performance analyses show that the proposed scheme effectively reduces computational and communication resource demands while maintaining communication and data security.

The pursuit of refined data analysis and the preservation of privacy in Big Data pose significant concerns. Among the paramount paradigms for addressing these challenges, differential privacy stands out as a vital area of research. However, traditional differential privacy tends to be excessively restrictive when it comes to individuals’ control over their own data. It often treats all data as inherently sensitive, whereas in reality, not all information related to individuals is sensitive and requires an identical level of protection. In this paper, we define secret specification-based differential privacy (SSDP), where the term “secret specification” implies enabling users to decide what aspects of their information are sensitive and what are not, prior to data generation or processing. By allowing individuals to independently define their secret specifications, the SSDP achieves personalized privacy protection and facilitates effective data analysis. To enable the targeted application of SSDP, we further present task-specific mechanisms designed for database and graph data scenarios. Finally, we assess the trade-offs between privacy and utility inherent in the proposed mechanisms through comparative experiments conducted on real datasets, demonstrating the utility enhancements offered by SSDP mechanisms in practical applications.

The proliferation of Internet of Things (IoT) devices has led to a surge in data generation within smart home environments. This data explosion has raised significant privacy concerns and highlighted a lack of user-friendly controls. Consequently, there is a pressing need for a robust privacy-enhancing mechanism tailored for smart homes, safeguarding sensitive data from a user-centric perspective. In this paper, we introduce the Fog-enhanced Personalized Differential Privacy (FEPDP) model, which utilizes the distributed nature of fog computing to improve data processing efficiency and security in smart homes. Specifically, the personalization, as a key feature of FEPDP, is manifested through an array of user-driven policy specifications, enabling home users to specify secret and privacy specifications for their personal data. These specifications not only enhance control over personal data but also align with the heterogeneous nature of smart home environments. Subsequently, aligned with fog-based smart home architecture, we propose two policy-driven partitioning mechanisms that utilize threshold partitioning based on dynamic programming to effectively implement FEPDP. Finally, comprehensive theoretical analysis and experimental validation across various statistical analysis tasks and datasets confirm that FEPDP achieves a superior privacy-utility trade-off for smart home data by leveraging non-sensitive data and fog-based partitioning.

This paper investigates the joint active transceiver and passive beamforming design to maximize the weighted sum-rate (WSR) of an IRS-aided multi-streams multiuser multiple-input multiple-output broadcast channel (MIMO-BC) downlink transmission system. Due to the coupling of the transceiver parameters, the considered WSR optimization problem is highly non-convex and thus challenging to solve. Different from the normally used methods, such as the weighted minimum mean-square error (WMMSE), we rely on the matrix fractional programming (MFP) theory to derive an effective algorithm to the WSR problem. Specifically, we reformulate the original problem into a tractable one by exploiting the special structure of the objective function, i.e., a MFP which involves a matrix ratio inside a logarithm in the objective function. An alternating optimization (AO) framework is then devised to decompose the reformulated problem into four subproblems, which optimize the introduced auxiliary variable, the transmit beamforming matrix, the receive matrix, and the reflecting beamforming matrix by fixing other variables respectively. Through the matrix quadratic transform, we reformulate the MFP problem as a convex one, and thus obtain the optimal transmit beamforming matrix. By leveraging the optimality conditions for unconstrained optimization problems, the optimal receive beamforming matrix and the introduced auxiliary variable are derived in closed form. For solving the passive beamforming subproblem, we propose an iterative algorithm based on successive convex approximation (SCA). Since the computational complexity of SCA is relatively high, we propose a computationally efficient method based on manifold optimization (MO) to optimize the passive beamforming matrix. Finally, we also consider the robust beamforming design when the system suffers from imperfect CSI. Simulation results demonstrate the effectiveness of the proposed methods.

With the prevalence of online social networks (OSNs), much personal information is collected and maintained by trusted service providers for third-party queries and analyses. Existing works regarding differentially private social network data publication overlook the fact that different users exhibit distinct privacy preferences or sensitivity inclinations. Neglecting these individual nuances may lead to privacy mechanisms that are overly conservative or inadequately protective. Furthermore, the injection of excessive noise into OSN data perceived by users as non-personal or less sensitive can incur additional privacy costs, resulting in lower service quality. This paper introduces a fine-grained, sensitivity-aware personalized edge differential privacy model (SPEDP) for OSNs. Specifically, SPEDP enables each OSN user to individually define the sensitivity level of their social connections, facilitating user-friendly personalized privacy settings. We design a privacy-aware mechanism that operates within a trusted service provider, capable of establishing privacy protection levels based on user-perceived sensitivity settings. Additionally, we propose a sensitivity-aware sampling mechanism to implement SPEDP. To further optimize the privacy mechanism, we explore a privacy threshold optimization strategy aimed at minimizing privacy budget waste. Finally, the personalized privacy protections and utility improvements achieved by the SPEDP mechanism are rigorously validated through theoretical analysis and comprehensive comparative experiments on benchmark datasets.

Recently, Li et al. proposed an identity-based linearly homomorphic network coding signature (IB-HNCS) scheme for secure data delivery in Internet of Things (IoT) networks, and they claimed that the IB-HNCS scheme can resist pollution attacks. However, this paper shows that the IB-HNCS scheme is vulnerable to pollution attacks, as anyone who only has the public parameter can forge a new file identifier or a valid signature on a corrupted data packet to pollute legitimate sensor data. To enhance security and performance in network coding-based IoT networks, we propose a secure and efficient certificateless linearly homomorphic network coding signature scheme for IoT data delivery, which is free of burdensome certificate management and key escrow issue. In addition, our scheme is proved to be secure against adaptive chosen identity and adaptive chosen subspace attacks under two types of adversaries in the algebraic group model and random oracle model. Therefore, our scheme can verify the validity of data packets and allow data packets to be computed, so as to resist pollution attacks. The performance evaluation demonstrates that our scheme is more efficient and practical than existing secure schemes. Specifically, for a 73-dimensional data vector, the costs of signature generation and verification in our scheme are reduced by 38.588%-86.076% and 38.570%-85.664% respectively under the symmetric bilinear pairing setting, and the costs of signature generation and verification in our scheme are reduced by 17.740%-49.752% and 29.697%-58.645% respectively under the asymmetric bilinear pairing setting.

As a distributed computing paradigm, federated learning (FL) enables multiple clients to cooperatively train in edge scenarios without sharing raw training data. Nonetheless, FL is vulnerable to Byzantine attacks due to its distributed nature. While numerous solutions have been proposed, they ignore the inconsistency of local models among clients caused by data heterogeneity (i.e., Non-IID), which severely degrades the performance of FL. Moreover, to further protect client privacy, complex security algorithms are integrated into FL, which seriously increases the privacy computation overhead on edge nodes. To tackle the above issues, this paper proposes a lightweight privacy-preserving federated learning framework, named LPP-FL, significantly improving the performance of FL against Byzantine attacks with Non-IID data. Specifically, we incorporate a correction-term into local model training to mitigate the inconsistency of local models among clients caused by data heterogeneity. Moreover, we design a secure protocol that is deployed on two servers, which achieves Byzantine-robust aggregation results while providing lightweight privacy protection for clients. Theoretical analysis demonstrates the security and robustness of LPP-FL. Extensive experiments show that LPP-FL exhibits superior performance against Byzantine attacks across various data distributions.

This paper proposes a highly secure and efficient certificateless authenticated key agreement (CL-AKA) scheme, which is particularly apt for deployment in vehicular access networks, as it improves not only communication but also computational efficiency in real-world scenarios where multiple vehicles concurrently access the internet via a limited number of base stations. The cornerstone of our CL-AKA scheme stems from an improved certificateless signature (CLS). Specifically, we re-design the key structure of CLS, allowing signers to locally maintain a single public key (instead of two public keys in most state-of-the-art works) as well as two private keys after key generation. With such a novel key structure, the proposed CLS facilitates pairing-free signature generation and verification and realizes efficient batch verification on the verifier’s end. Moreover, a signer only needs to disseminate one public key to verifiers, thus saving communication bandwidth. In addition to the advanced CLS, we develop a CL-AKA scheme that efficiently handles network access requests from multiple vehicles at base stations. To resist physical attacks and achieve highly secure key management, we further integrate the Physical Unclonable Function (PUF) into our scheme. Formal security proofs demonstrate that the proposed CL-AKA scheme is secure against conventional attacks and preserves common security properties such as forward secrecy and session key independence. Finally, we develop a proof-of-concept prototype and conduct extensive experiments to demonstrate the efficiency and practicality of our scheme.

Throughput-optimal dynamic broadcasting is an essential cornerstone for the efficient operation of Multi-hop Wireless Networks (MWNs). Most existing algorithms for this problem were developed assuming static interference environments and network connectivity. However, wireless interference environments and network connectivity are inherently time-varying in real-world scenarios, primarily due to uncontrollable interference sources and unreliable links. Such time-varying characteristics make these existing algorithms less robust. In this paper, we study the robust throughput-optimal dynamic broadcasting for MWNs with multi-dimensional time-varying characteristics in terms of interference environments, network connectivity, and data arrival. We model the time-varying link existence states using a random process and characterize the time-varying interference environments through a dynamic variant of the classical Signal-to-Interference-plus-Noise-Ratio (SINR) model. In this variant, the SINR model parameters are dynamically adjusted over time by an adversary. Based on this, we first design a Robust Throughput-optimal Dynamic Broadcast (RTDB) algorithm which makes efficient slot-based max-weight link scheduling, power allocation, and data forwarding decisions in each time slot. We then prove its throughput-optimality in time-varying acyclic directed MWNs under the dynamic SINR model. The effectiveness of RTDB is validated via numerous simulations.

Enhancing the prediction of volatile and intermittent electric loads is one of the pivotal elements that contributes to the smooth functioning of modern power grids. However, conventional deep learning-based forecasting techniques fall short in simultaneously taking into account both the temporal dependencies of historical loads and the spatial structure between residential units, resulting in a subpar prediction performance. Furthermore, the representation of the spatial graph structure is frequently inadequate and constrained, along with the complexities inherent in Spatial-Temporal data, impeding the effective learning among different households. To alleviate those shortcomings, this article proposes a novel framework: Spatial-Temporal fusion adaptive gated graph convolution networks (STFAG-GCNs), tailored for residential short-term load forecasting (STLF). Spatial-Temporal fusion graph construction is introduced to compensate for several existing correlations where additional information are not known or unreflected in advance. Through an innovative gated adaptive fusion graph convolution (AFG-Conv) mechanism, Spatial-Temporal fusion graph convolution network (STFGCN) dynamically model the Spatial-Temporal correlations implicitly. Meanwhile, by integrating a gated temporal convolutional network (Gated TCN) and multiple STFGCNs into a unified Spatial-Temporal fusion layer, STFAG-GCN handles long sequences by stacking layers. Experimental results on real-world datasets validate the accuracy and robustness of STFAG-GCN in forecasting short-term residential loads, highlighting its advancements over state-of-the-art methods. Ablation experiments further reveal its effectiveness and superiority.

Online social networks have emerged as a significant data source, but the extensive collection and utilization of personal information have given rise to profound concerns regarding privacy. From a legislative and policy perspective, and in alignment with the concept of privacy as control, users have the right to control their personal privacy information. However, users often encounter challenges in terms of understanding and effectively managing their privacy settings to align with their specific privacy requirements. To address this issue, in this paper, we incorporate the concept of trust and propose a trust-based personalized differential privacy model for online social networks, denoted as TPDP, which relies on a trusted central server to facilitate its operation. Specifically, when a user requests access to another user’s personal information, the TPDP mechanism provides a privacy response, where the privacy level is determined based on the direct and indirect trust values among users, calculated automatically by the trusted central server. Furthermore, the proposed TPDP model offers user-to-user personalized differential privacy protection from the perspectives of network structures, trust-related factors, and trust propagation patterns. Finally, we validate the model’s feasibility and assess the privacy-utility trade-off, as well as its robustness against attacks, through theoretical analysis and performance evaluation.

Data privacy breaches have prompted growing concerns regarding privacy issues on social networks. Preserving the privacy of links in the directed social graph, where edges signify the information flow or data contributions, poses a formidable challenge. However, existing methods for uncertain graphs primarily target undirected graphs and lack rigorous privacy guarantees. In this paper, we present a personal evidence protection algorithm called PEPA, which provides formally dual privacy guarantees for directed social links. Specifically, we implement out-link privacy to protect the out-links of nodes. Despite this protection, the exposure of in-links can still compromise privacy, potentially affecting service quality. To address this, we further introduce an uncertain directed graph algorithm as a post-processing approach for out-link privacy. This algorithm injects uncertainty into nodes’ in-links, effectively transforming the original directed graph into a probability-driven uncertain structure. Additionally, we propose an effective noise optimization method. Finally, we evaluate the trade-off between privacy and utility achieved by PEPA through comparative experiments. The results demonstrate privacy enhancements of PEPA compared to the$(k, \varepsilon )$-obfuscation algorithm and utility improvements over the RandWalk algorithm and UG-NDP. Particularly, PEPA demonstrates approximately a 2-fold improvement in utility compared to PEPA without noise optimization.

Differential privacy has received considerable attention as a privacy concept for releasing statistical information from datasets. While differential privacy provides strict statistical guarantees, it is equally crucial to investigate how these guarantees interact with individual privacy preferences and privacy policies. Existing solutions, such as one-sided differential privacy, treat all sensitive records equally in terms of privacy protection, although datasets can be classified based on predetermined privacy policies that differentiate between sensitive and insensitive records. In this paper, we present a novel concept of privacy termed One-sided Personalized Differential Privacy (OSPDP), offering verifiable privacy assurances at the user level for sensitive records derived from privacy policies. Specifically, OSPDP enables data owners to articulate their privacy needs more flexibly, avoiding a one-size-fits-all approach to privacy protection and potentially establishing a dichotomous privacy policy regarding the sensitivity of records. Furthermore, the truthful release or legitimate disclosure of non-sensitive records reduces unnecessary privacy consumption and can be utilized to significantly enhance data utility. Additionally, we present several well-performing mechanisms for achieving OSPDP. Finally, we evaluate and analyze the trade-off between privacy and utility of the proposed mechanisms through extensive experiments.

In the context of Industry 4.0 and the rise of intelligent manufacturing, the quality of industrial products is becoming more and more important. Strip steel surface defect detection, as a key link in industrial production, is crucial to ensure the quality of industrial products. However, due to the irregularity of the defect scale and the inconspicuous defect features in the surface defect image of strip steel, it is difficult for the existing detection algorithms to realize the effective detection of defects. In order to better extract the features of defects and improve the network’s ability to detect defects, this paper proposes an algorithm for detecting surface defects on industrial strip steel based on receptive field and feature information supplementation. First, we design a receptive field (RF) module to replace the residual structure in the C3 module, which we name C3RF. This module can effectively increase the network’s receptive field, allowing the network to fully capture irregular defect features without increasing the cost. Second, for the characteristics that defective features are not obvious and tend to lose detail information as the network deepens, an extra information supplemental branching feature fusion pyramid (EFPN) is proposed on the basis of the original PAFPN architecture to compensate for the detail information that is lost by the fragile features in deeper layers. Finally, convolutional block attention module (CBAM) is introduced to replace the spatial pooling pyramid (SPPF) in the baseline network, which enhances the contrast between defects and backgrounds, and improves the classification and localization ability of the network. Our network achieves an accuracy of 82.2% on the publicly available strip steel defect detection dataset, which is a 4.0% improvement over the baseline. The results show that the network constructed in this paper can realize effective defect detection.

With the rapid development of information technologies such as cloud computing, big data, artificial intelligence, and edge computing, data centers have become essential infrastructure supporting the modern information society. When constructing data center networks, as the network scale increases, both latency and cost also grow. Therefore, it is essential not only to consider network scalability but also to focus on link overhead and communication latency. The hypercube is an excellent base topology for constructing data center networks. The Möbius cube, a version of the hypercube, not only retains the hypercube’s favorable properties, but also outperforms it in terms of link overhead and network diameter. In this paper, we propose a new server-centric data center network architecture, called MBDC, which is based on the Möbius cube. For networks of the same scale, MBDC achieves a smaller diameter than most existing server-centric networks. Additionally, we present an adaptive fault-tolerant routing scheme for MBDC, which is based on an improved local security information model. Extensive evaluations demonstrate that MBDC is an attractive data center network for constructing low-latency and cost-effective data centers.

YOLOv5s is a classic deep learning target detection framework with balanced speed and performance in recognition, which is widely used in industrial defect inspections. YOLOv5s relies on the residual structure in the C3 module for feature extraction, but due to its simple structure and the small, fixed convolution kernel, it is difficult to accurately and completely extract target features when applied to the detection of defects with inconspicuous features and irregular shapes, which results in a decrease in recognition accuracy. To solve this problem, this paper proposes an improved YOLO architecture based on receptive field enhancement and redundant feature reuse. Firstly, the method designs a redundant feature reuse module (RFRM) to replace the residual structure in the C3 module for feature extraction. This module can deepen the network with a smaller cost and enhance the network’s ability to extract features. Furthermore, the feature reuse process allows the network to deepen while retaining detailed information, enabling the network to classify and localize more accurately. Secondly, a simplified convolutional block attention module (SCBAM) is designed and embedded into the neck of the detection network. This module directs the detection network to focus more on inconspicuous defect features and reduce interference from background noise in the feature map, thereby improving the accuracy of defect classification and localization. Finally, a receptive field enhancement module (RFEM) is designed and inserted between the neck and head of the detection network. This module adds only a small computational cost to expand the receptive field of the network, enabling it to further extract and comb irregular features from the neck in a comprehensive manner, making the features reaching the detection head more complete. Applying the above improvements to defect detection, the experimental results show that the improved YOLO architecture based on receptive field enhancement and redundant feature reuse proposed in this paper has better detection performance in defect image detection scenarios compared to other mainstream target detection methods.

Federated learning (FL) is a distributed machine learning framework enabling multiple clients to collaboratively train a shared ML model without sharing raw data. Despite its aim to safeguard data security and privacy, FL faces risks from advanced adversarial attacks like membership inference attack (MIA), potentially leaking sensitive information. To counter these threats, differential privacy (DP) methods add noise to shared model parameters. However, traditional DP methods struggle with balancing model accuracy, training efficiency, and privacy protection, often compromising one for the other. Additionally, uniform DP mechanisms may not cater to varying client privacy and performance needs. To tackle these challenges, we propose a federated learning framework based on localized random differential privacy (FedLRDP). This approach empowers each client to control noise levels based on their privacy requirements, enhancing model performance while preserving data privacy. We further optimize client-side loss functions to enhance model performance. Theoretical analysis establishes the convergence bounds for FedLRDP, demonstrating its superior convergence performance. Experimental results on MNIST reveal that FedLRDP improves model accuracy by 3.28% compared to traditional DP methods while mitigating MIA with a 72.48% lower attack success rate than FedAvg. Moreover, on EMNIST, FedLRDP boosts model accuracy by 7.31% compared to traditional DP methods, maintaining a 59.4% lower attack success rate than FedAvg. These findings underscore FedLRDP’s efficacy in meeting client privacy needs while enhancing model performance.

Mobile edge computing (MEC) is considered a promising technology to provide low-latency services by keeping computing and other resources physically close to where they are needed. The functions implemented through network function virtualization (NFV) technology in MEC are called virtual network function (VNF) instances, and the deployment and scheduling of VNF instances have always been a hot topic. The deployment refers to deploying instances on the edge servers, while scheduling refers to allocating resources to complete user requests. However, most of the existing works fail to jointly consider the deployment and scheduling of VNF instances, which cannot complete user requests reasonably and efficiently. Besides, the deployment cost can be significantly reduced by making users share the same type of instances instead of assigning one to each user. Therefore, the objective of our article is to investigate the efficient deployment and scheduling of VNF instances that are shared among different users under constraints of user delay and network resources. We first build a VNF instance deployment and scheduling model in MEC networks to study how to minimize cost and maximize network throughput under the constraints of user delay and the computing and storage resources of cloudlets. Then, taking advantage of its sharing feature, we propose a set covering-based efficient deployment and scheduling scheme called SCEDS and evaluate its performance by extensive simulations. The simulation results demonstrate the superiority of our proposed method compared to the existing ones.

The rapid evolution of the smart grid has made the security and reliability of communication within the power system an urgent and critically important issue. To address this challenge, authentication and key agreement (AKA) protocols have gained significant attention and are regarded as indispensable tools for ensuring the secure operation of the smart grid. However, traditional AKA protocols are plagued by a series of issues, including cumbersome certificate management, delayed certificate revocation, and vulnerability to man-in-the-middle attacks. With the emergence of certificate-less public key cryptography (CL-PKC), the integration of conventional AKA protocols with CL-PKC has emerged as a prominent trend. This paper presents an enhanced certificate-less AKA protocol for smart grids, named ECL-AKA. Firstly, the paper outlines the architecture and security model of this protocol. Subsequently, it presents the complete workflow of the ECL-AKA protocol. Notably, the ECL-AKA protocol introduces a private key verification step before key agreement, allowing for rapid screening of malicious requests at a lower computational cost, thereby enhancing the protocol’s resistance to various types of attacks. In addition, the ECL-AKA’s security is formally established through rigorous theoretical proofs based on the random oracle model in the paper. Finally, comparative experimental analysis demonstrates that the ECL-AKA exhibits lower computational and communication overhead while satisfying essential security attributes.

The massive amount of data on the Internet of Things (IoT) drives recommendation systems (RSs) based on graph neural network (GNN) to fully play a role in improving user experience. However, data sharing and centralized storage can pose serious security threats. Even though federated learning (FL) can render data “available but not visible,” the heterogeneity of graph data within IoT institutions can result in limitations in recommendation performance. To address the issues, we propose a privacy-preserving decentralized cross-institutional federated graph learning framework called DCI-PFGL for IoT service recommendation, which alleviates the negative impact of data heterogeneity while protecting data security. Our approach extracts graph feature embeddings using the shortest path graph kernel. These embeddings are then anonymized and compared on a blockchain through smart contracts, which helps match partner IoT institutions with lower data heterogeneity. Subsequently, IoT institutions within the same partition collaborate in federated graph learning. We also ensure the protection of transmitted information through differential privacy measures. Finally, we conduct comprehensive experiments on two benchmark data sets. Results demonstrate that DCI-PFGL outperforms other approaches in terms of system accuracy and collaboration costs.

Sharing the big data generated by IoT via cloud is slow and expensive. Besides, transmitting and sharing data among IoT devices via cloud may be insecure. To address these issues, a novel efficient and secure data sharing scheme termed EB-SDSS (Edge Blockchain Secure Data Sharing Scheme) is proposed in this paper for edge-enabled IoT applications. EB-SDSS constructs a blockchain on edge servers. It guarantees the confidentiality and unforgeability of data by combining the symmetric encryption scheme with an edge blockchain. To ensure the device authenticity and the reliability of shared data, EB-SDSS adopts a certificateless signature scheme. It also provides efficient large-scale data searches for IoT devices through a locality-sensitive hashing algorithm. EB-SDSS has been proven to be secure against the adaptive chosen message attacks under the random oracle model. The experimental results indicate that EB-SDSS is feasible for IoT inter-device data sharing.

Deep learning is a thriving field currently stuffed with many practical applications and active research topics. It allows computers to learn from experience and to understand the world in terms of a hierarchy of concepts, with each being defined through its relations to simpler concepts. Relying on the strong capabilities of deep learning, we propose a convolutional generative adversarial network-based (Conv-GAN) framework titled MalFox, targeting adversarial malware example generation against third-party black-box malware detectors. Motivated by the rival game between malware authors and malware detectors, MalFox adopts a confrontational approach to produce perturbation paths, with each formed by up to three methods (namely Obfusmal, Stealmal, and Hollowmal) to generate adversarial malware examples. To demonstrate the effectiveness of MalFox, we collect a large dataset consisting of both malware and benignware programs, and investigate the performance of MalFox in terms of accuracy, detection rate, and evasive rate of the generated adversarial malware examples. Our evaluation indicates that the accuracy can be as high as 99.0% which significantly outperforms the other 12 well-known learning models. Furthermore, the detection rate is dramatically decreased by 56.8% on average, and the average evasive rate is noticeably improved by up to 56.2%.

With the development of big data technology, the power industry has also entered the data-driven intelligence era. Cloud computing-based smart grids give the power industry stronger capabilities in data analytics. Electricity load forecasting in the cloud helps smart grids allocate resources appropriately. However, the users' privacy is easily compromised in the load forecasting process with cloud computing. The electricity usage data collected by the system may contain sensitive information about the users, which could lead to serious privacy leakage. In order to solve the issues, we propose a novel privacy-preserving cloud-aided load forecasting scheme for the cloud computing-based smart grid. It contains a secure online training algorithm and an efficient real-time forecasting algorithm. Meanwhile, the two-party interaction security scheme is more suitable for real-world applications. Before being sent to the cloud server, the control center of the smart grids encrypts the data using homomorphic encryption. During the process of model training and forecasting, the data remains securely encrypted at all times to avoid the risk of data privacy breaches. Finally, security and experimental analyses show that our scheme effectively avoids privacy leakage while reducing resource consumption.

Social recommendation improved the quality and efficiency of recommendation but increased the risk of privacy leakage, especially with the introduction of social networks. Consequently, the social recommendation considering user privacy has drawn tremendous attention from academia to industry. Nevertheless, most of the existing work regards the recommender systems as static, ignoring the diffusion of social influence over time. In this article, we propose a secure and efficient framework, temporal privacy-preserving social recommendation model (PrivTSR), to capture the changes of user preference for items and item types with time. PrivTSR first utilizes differential privacy to encrypt the data owned by the data owner. Then, inspired by the long short-term memory (LSTM), at each time step the initial user embedding and the initial item embedding are generated via DeepWalk as new ratings of users for items emerges in the user–item-type graph. The initial user-preference embedding is generated randomly at the first time step, and it is equivalent to the updated embedding of the previous time step for the later time steps. Most importantly, on the social graph, PrivTSR updates the user embedding and the user-preference embedding with graph attention convolutional network and graph attention diffused network, which aggregates (diffuses) social influence from (to) neighbors in depth and breadth. On the user–item-type graph, the user embedding and the item embedding are updated by aggregating the embedding of users and items in the six paths. Final, taking into account the users’ preference for items and item types, PrivTSR predicts the ratings of users to the items for the next time step. The extensive experiments are conducted on two real-world datasets, which demonstrated the superiority of our model over several competitive baselines.

Data aggregation (DA) plays an important role in the context of Internet of Things (IoT). Although some favorable solutions have been proposed to improve the performances of DA, the complex collusion attacks are often ignored and may produce more serious negative impact on aggregation accuracy. In this article, we design a novel dynamic robust iterative filtering (DRIF) mechanism to enhance the quality of service of IoT applications and improve the vulnerability of DA to the collusion attack. First, the initial reputations based on the maximum likelihood estimation are assigned to sensor nodes in order to resist the collusion attack. Second, the sensor nodes obtain the aggregation result through iterative filtering so as to ensure the accuracy of DA. Especially, a weight updating scheme is proposed to eliminate the negative effect of the accidental anomaly or collusion nodes. Finally, the simulation study indicates that the proposed DRIF mechanism is effective and it can achieve a higher accuracy in the presence of complex dynamic collusion attacks.

This paper addresses the problem of reliable communications for cooperative learning on Internet-of-Vehicles, where a large amount of data from users and services needs to be processed. Previous works have proposed various cooperative learning schemes, but they often assume that the communications between vehicles are reliable, without considering how to achieve this in an Internet-of-Vehicles network. This paper is the first one that implements an abstract MAC layer using a distributed deep reinforcement learning scheme, which can directly meet the reliable communication requirements of cooperative learning in previous works. Our abstract MAC layer performs two operations:acknowledgement, which makes sure that all vehicles can successfully broadcast their messages to all of their neighbors, andprogress, which ensures that each vehicle can receive at least one message from its neighbors. These operations facilitate vehicles to exchange and update their training models in a cooperative learning service. Our simulation results show the efficiency and fairness of our deep reinforcement learning abstract MAC layer.

The significance of RFID-based information collection is becoming increasingly visible as more and more sensor-augmented RFID systems are deployed. Tag information collection aims at efficiently and accurately collecting valuable information from target objects attached with RFID tags. Polling-based information collection can effectively avoid response collisions between RFID tags, and it is widely adopted to accurately inventory tags. However, in the traditional polling mode, a polling vector can only be used to query a tag at a time, which is inefficient. In this paper, we design a double polling mode to improve the utilization of polling vectors, which can simultaneously interrogate a pair of tags. Afterwards, several techniques are developed to reduce the polling vector length. Firstly, the Basic Double Polling-based protocol (BDP) employs double indexes to collect information, which greatly reduces the number of polling vectors. Secondly, the Segmented Double Polling-based protocol (SDP) divides the double indexes into several segments to cut the polling vector length down. Thirdly, the Partial Double Polling-based protocol (PDP) replaces the double index with the size of the empty segment between two adjacent non-zero indexes to further reduce the average polling vector length. Finally, the Differential Double Polling-based protocol (DDP) utilizes the size of the empty segment between two double indexes to improve the utilization of polling vectors. After that, extensive theoretical analyses and simulations are conducted, which demonstrate the feasibility and effectiveness of the proposed protocols.

The widespread deployment of Internet of Things (IoT) devices brings more and more computation intensive or delay sensitive tasks, causing a series of challenges to efficient services. Collaborative edge computing is an effective way to solve them, where the tasks will be processed in the devices, edge servers, and cloud server in parallel. However, the above collaborative paradigm requires dense deployment of base stations (BSs) and consumes lots of energy. To address this problem, in this paper, we introduce energy harvesting technology and construct a collaborative edge computing system powered by hybrid energy. Considering the highly variable task execution delay caused by the resource contention and the unstable energy state, we further introduce the Holt Linear Exponential Smoothing Prediction to predict the delay and then propose an Online Server Control schedule called OSC based on Lyapunov optimization to obtain the optimized offloading decision without the knowledge of the future system state. The extensive simulations illustrate that the proposed OSC outperforms other benchmark ones.

In the current hypergrowth phase of the Internet of Things, cross-domain data access becomes more and more frequently. Whereas, the lack of trust between domains makes cross-domain data access extremely hard. Traditional schemes typically depend on a third party to establish trust between data accessing entities, which can easily result in single point of failure. To conquer the aforementioned challenge, this paper proposes BSCDA, a blockchain-based cross-domain data access scheme designed to enable secure data transmission across domains. The decentralization, transparency, and anti-tampering features of blockchain perfectly solve the issue of single point of failure and foster trust among various domains. Specifically, a certificate management method is developed to address the certificate storage issue by leveraging a mapping table to store the revocation certificate index on the blockchain. This method not only ensures the verifiability of the certificate but also reduces the storage overhead. Additionally, a four-party key agreement mechanism is designed to guarantee the secure data transmission during the process of cross-domain data access. Security analysis prove the feasibility of our proposed scheme. Extensive experiments demonstrate the superiority of our scheme in cross-domain data access.

Disseminating continuous packet flows injected at multiple location-random source nodes to all network nodes, known as the multi-source dynamic global broadcast problem, is a fundamental building block for wireless multi-hop networks to run smoothly and efficiently. Previous studies on dynamic global broadcast all assume reliable communications. However, in realistic wireless networks, there exist unpredictable transmission failures caused by the randomized signal interference from uncorrelated wireless networks sharing the same spectrum or even malicious attackers. In this paper, by integrating the Signal-to-Interference-plus-Noise-Ratio (SINR) model, multi-channel communication mode, and randomized malicious channel jamming controlled by an adaptive adversary, we present an SINR-based adversarial channel jamming model to capture the unpredictable transmission failures in a wireless multi-hop network. We first propose a distributed Jamming-resilient Multi-source Static Broadcast (JMSB) algorithm based on random channel selection and message transmissions for multi-hop wireless networks under the above SINR-based adversarial channel jamming model. We then propose a distributed stable Jamming-resilient Multi-source Dynamic Broadcast (JMDB) algorithm which iterates JMSB repeatedly and efficiently in a two-stage manner. We derive the maximum supportable broadcast throughput of JMDB under the stability guarantee, i.e., the expected boundedness on the queue length of each network node and expected broadcast latency for each injected packet. Simulation results shows the stability and throughput efficiency of our proposed JMDB algorithm.

Most data center services are finished by the cooperation among the connected servers. However, the malicious attackers always try to divide the network into disconnected components to start some attacks, such as the address resolution protocol (ARP) attack, the denial of service (DoS) attack, the botnet attack, and so on. The connectivity is an excellent indicator to measure the reliability and fault-tolerant ability of the network. Whereas, the traditional connectivity and current conditional connectivity cannot well reflect the fault-tolerant performance of the network when attackers are a block or have a certain structure and the components of the remaining network still have a certain structure. Based on this fact, we propose a new measure: the double-structure connectivity, which can accurately reflect the fault-tolerant ability of the network when attackers are structured and each component of the network has a certain structure after removing the attacked servers. Meanwhile, a hypercube is a high-performance interconnection network that can also be used to design some data center networks. Therefore, we study the double-structure fault-tolerance of the hypercube and determine the double-structure connectivity of distinct structures of the hypercube. Furthermore, we propose algorithms to construct structures of attackers directly to measure the fault-tolerant ability of the hypercube under this attack. Our results can be applied not only to interconnection networks but also to some data center networks.

Topology design is vital to the high performance data center networks. Due to the limited scalability, many traditional server-centric data center networks are confronting the updating and upgrading hurdles. To address the issue, this paper proposes a highly scalable DCell-based server-centric data center network topology, called HS-DCell, which can use inexpensive and typical switches and servers with only three network ports to achieve excellent network performance HS-DCell can accommodate a large number of servers, and its diameter increases linearly with the growth of network levels, which is better than that of most existing server-centric networks. Furthermore, a fault-free routing algorithm and a fault-tolerant routing algorithm are developed based on HS-DCell. Compared with other mainstream server-centric network topologies, the experimental results show that HS-DCell has obvious advantages in many key performance indicators including scalability, fault tolerance, and server port utilization.

Link scheduling plays a pivotal role in accommodating stringent reliability and latency requirements. In this paper, we focus on the availability and effectiveness of applying protocol interference model (PIM) under Rayleigh fading model to solve the problem. The motivation is that PIM caters to distributed link scheduling algorithm design, but usually lead to irrationality due to its localization behavior. While Rayleigh fading model can accurately describe the inherent characteristic of wireless signal propagation, but the features of global interference and channel fading make algorithm design more challenging. To be specific, we first remove the effect of channel fading on algorithmic design by establishing the relationship between Rayleigh fading model and non-fading model. We then propose a centralized once link elimination (OLE) algorithm by utilizing local nature of PIM, and achieve its distributed implementation based on the message delivery with time complexity of$O(\Delta _{\max }\ln \Delta _{\max })$, where$\Delta _{\max }$is the maximum number of nodes around a given node inside some range. Furthermore, based on random contention resolution, we design another distributed algorithm to schedule all the links within$O(\Delta ^{3}_{\max }\ln \Delta _{\max })$rounds. Simulations show that the PIM is of great confidence as same as Rayleigh fading model, and the proposed algorithms outperform three popular link scheduling algorithms.

The growing prevalence of graphs representations in our society has led to a corresponding rise in the publishing of graphs by researchers and organizations. To protect the privacy, it is important to ensure that graphs including sensitive data are not disclosed. Since the weight of edges could be utilized to infer confidential information, the graph should be privately published to avoid ethical and legal issues. In this paper, we propose a novel method for privately publishing shortest paths while preserving the privacy of sensitive edge weights in graph. Specifically, we divide the edge weights into internal and external edges based on their edge betweenness centrality. Then, we give two different differentially private algorithms to perturb edge weights based on the distinction between internal and external edges, respectively. To reduce the error ratios between differentially private shortest paths and real shortest paths, we employ edge betweenness centrality to search for the shortest path, which is closest to the true one. Our experimental results show that our mechanisms can effectively reduce the error in the average shortest path distance by 1.1% for large graphs, while for the shortest path change rate, our mechanisms can reduce it by 8.3%.

Airborne tactical networks (ATN) play a pivotal role in enabling information sharing between manned and unmanned military aircrafts. The design of effective ATNs faces two significant challenges: the network ossification problem and the complexity associated with managing heterogeneous resources. Wireless network virtualization provides a practical solution for the first challenge by abstracting, isolating, and sharing wireless resources among different entities. Flexible and scalable virtual request embedding (VRE) algorithms have the potential ability to address the other challenge. However, existing VRE algorithms are not suitable for the virtualization of an ATN because they do not adequately consider key factors such as global interference, reliability and delay-sensitive information sharing in the air-battlefield context. In this paper, we propose an analytical framework of joint wireless network virtualization and resource allocation in the context of an ATN. This framework ensures coordination between physical node and link resources for the VRE. Based on the proposed framework, we design a centralized embedding mechanism that maps available physical resources to served users by constructing a directed resource topology and designing wireless link scheduling algorithms. Furthermore, we design two VRE algorithms that account for two types of delay sensitivity: transmission time and waiting time, depending on whether virtual requests are split or not. Through simulations, we validate the effectiveness of our algorithms and analyze the impact of key system parameters on the delay performance.

Surface electromyography (sEMG) signal is a physiological electrical signal produced by muscle contraction. Different gestures can be effectively recognized from the characteristics of the sEMG signal. Currently, convolutional neural networks (CNNs) have been widely used in sEMG gesture recognition systems due to their capabilities in acquiring spatial features of sEMG signals. However, these classical CNNs are inefficient in extracting temporal correlation that resides in the time serials of sEMG signals, which is definitely important for gesture recognition. To overcome such a drawback of traditional CNN-based gesture recognition methods, we propose a multichannel hybrid deep learning model for gesture recognition by combining the multichannel CNNs with a gated recurrent unit (GRU). Specifically, we use multiple CNNs to preprocess the original multichannel EMG signals in a one-by-one manner to obtain the spatial features in the current observing window. The outputs of the multiple CNNs are concatenated and fed to a temporal-feature extracting module, which is designed by cascading a GRU with an attention mechanism. Through the GRU, the temporal features of successive signal frames can be established, while the attention mechanism is introduced to further focus on the key information in recognizing the gestures, which is beneficial to improve the robustness and accuracy of the model. Experiments show that the recognition accuracy of the proposed method reaches 97.6% and 96.7% on the Ninapro DB2 and Ninapro DB5 datasets, respectively. Compared with the classical CNN method, the performance improvement is 2.9% and xx% higher than that of the traditona CNN model, respectively.

Trajectory tracking of zebrafish is an important requirement in studying neurological disorders and developing new psychoactive drug. However, many challenges emerge for stable tracking, since zebrafish are similar in appearance, occlusion, agile, non-linear in moving and easy to swarm, all of which will lead to mistrack for multiple fish. And there is no precedent for tracking zebrafish through embedded edge artificial intelligence device. To overcome these difficulties, we present a tracking system for zebrafish based on RK3588-S. First, We construct an embedded edge AI hardware system consisting of two cameras driven by the RK3588-S, one for the front view and the other for top view of the fish. Then, we develop a 2D tracking algorithm based on YOLOv5 and the Observation-Centric Simple online and real-time tracking (OC-SORT) algorithm, which are transplanted to the RK3588-S for tracking the top and front views of the fish at the edge device. Compared with the previous methods, our method has fewer ID exchanges and highly real-time. Moreover, we apply the MQTT mechanism to establish communication links between the edge and the cloud to reliably transmit data to the cloud. The correspondence between cloud server and embedded AI is 1: N. Finally, we design a multi-view data fusion association algorithm to fuse the data of the two views in the cloud, which are further utilized to build the 3D tracklets of the zebrafish.

Drug box recognition is an integral part of the pharmacy automation system (PAS), which checks for discrepancies between the drugs provided by the system and the doctor’s prescription with the help of modern image recognition techniques. Although deep learning has facilitated the development of pharmacy automation systems, practical applications still face challenges. First, pharmacies update drugs frequently, and many pharmacies across the country are trained independently, which requires consuming massive computational resources. Secondly, the equipment performance of pharmacies is poor, and it’s hard to guarantee the real-time and accuracy of recognition. Therefore, we propose a cloud-side collaborative drug box recognition system. When new drugs are added, the new model is trained in the cloud and uniformly distributed to each edge through this architecture. In terms of real-time recognition, an improved lightweight YOLOv5 model is added to the edge part, and a text recognition module is deployed in the cloud to validate the recognition results at the edge. This cloud-edge collaboration architecture not only ensures the accuracy of recognition, but also reduces the burden on the compute edge, ensures the real-time recognition.Experimental results show that the proposed cloud-edge architecture reduces the recognition latency by 37.18% and achieves a precision of 97.47%. The improved YOLOv5 model reduces GFLOPs by 45% while achieving a 1.6% precision improvement.

Medical data visualization is instrumental in assisting disease diagnosis and exploring brain function and structure.In this paper, we constructed a brain connectivity network using changes in BOLD signals at different time intervals and identified frequent characteristics to help doctors quickly pinpoint areas of interest.To study the changes in connectivity between brain regions, we visualize frequent sequences and compare them, highlighting important temporal features of patient brain areas.This makes the study and analysis of fMRI data more convenient and assists doctors in investigating abnormalities in the connections between brain functional areas.

In recent years, the graph feature mining method of brain connection data based on graph theory has been regarded as a popular and universal technology in the field of neuroscience. How to mine valuable information from brain connection data has become a research hotspot. Current research shows that the pathogenic factors of attention deficit and hyperactivity disorder (ADHD) may be caused by the abnormal connection between brain network structures. In order to find out the pathogenic factors of ADHD patients, we also carried out frequent sub-graph mining on the connectivity graph data of brain functional network. By constantly adjusting the sup-port threshold, all the subgraphs of ADHD patients and healthy control group were mined, and the differences in brain region connectivity were successfully found out. By combining the recently introduced neural document embedding model with traditional pattern mining techniques, we regard the brain network connection structure graph as the document and frequent subgraph as the atomic unit of the embedding process. By learning the mapping, each graph can be mapped to a D-dimensional continuous vector. The mapping needs to capture the similarity between the graphs. Feature vectors can be used as the direct input of graph classification in many traditional machine learning methods. Finally, support vector machine in machine learning is used to verify the accuracy of classification, and the results show that the accuracy is high.

Internet of Medical Things (IoMT) technologies significantly improve the quality of health care, especially at the time when COVID-19 is becoming a worldwide pandemic. Due to the complexity of devices and user nodes in the IoMT system, there should be some ways to ensure the security and quality of the service or information. Decentralized trust management techniques are efficient means of promoting application security and reliability in these cases. However, the majority of currently utilized access control schemes cannot be applied in decentralized trust management systems or perform poorly owing to the numerous restrictions of decentralized systems. In this article, we present a policy-hiding and multiauthority key generation CP-ABE scheme (PM-CPABE) for decentralized trust management systems, which could provide fine-grained access control capabilities. Meanwhile, the proposed scheme does not require any fully trusted entity, thus it can be well adapted to decentralized trust management systems. The scheme also implements policy hiding to protect user privacy. In addition, it supports large universe and outsourced decryption. The security analyses and performance comparisons give evidence of our scheme is secure and efficient.

Internet of Things (IoT) devices usually stores data on clouds for computational overhead offloading and easy data sharing. The data owners, as a result, usually have concerns about the security and privacy of their data stored in such cloud-assisted IoT (C-IoT) systems. Traditional encryption and search primitives, including attribute-based encryption (ABE) and public-key encryption with keyword search (PEKS), however, suffer from high overheads in decryption and revocation, and privacy leakage in search. To address these issues, we propose an efficient revocable and searchable multiauthority ABE (MA-ABE) scheme named ERS-ABE, which utilizes blockchain (BC) technology to implement keyword-based search and dynamic user management. ERS-ABE also adopts cloud-assisted decryption to improve the efficiency of IoT devices. It has been proven to be secure against the selective replayable chosen-ciphertext attacks and the chosen-keyword attacks under the random oracle model. The feasibility and efficiency of ERS-ABE have been evaluated through theoretical analysis and extensive simulation studies. The results indicate that EAR-ABE performs better over the state-of-the-art in both storage and computational overheads. Particularly, the operations that are usually done by a central server but taken by a BC in EAR-ABE cost only a few seconds.

With the wide deployment of Internet of Things (IoT), blockchain systems have been playing a crucial role to establish a trusted computing environment among potentially mistrusting agents without depending on a centralized server. Different from previous blockchain consensus protocols adopted in IoT, which rely on efficient and stable transmissions, in this article, we consider how to reach blockchain consensus in wireless networks without reliable network support. Specifically, a realistic signal to interference plus noise ratio (SINR) model is adopted to depict the unreliable transmissions in wireless channels. Based on the SINR model, a distributed and randomized consensus algorithm is proposed to reach$k$-times consensus among$n$devices within$O(k+\log n)$time steps with high probability. Note that the time complexity of our algorithm is asymptotically optimal since$\Omega (k+\log n)$is a lower bound to achieve$k$-times consensus in a distributed environment. We conduct both rigorous theoretical analysis and extensive simulations to validate our method. It is believed that our work can facilitate the implementation of blockchains in many wireless scenarios in which the reliable and fast transmissions cannot be guaranteed.

With the widespread application of real-time embedded systems (ESs), the contradiction between the energy consumption requirements of modern processors and the limited battery capacity becomes more obvious. Dynamic voltage scaling (DVS) has been proven to be one of the most effective technologies for energy management. However, recent studies have shown that the use of DVS leads to a significant increase in the transient fault rate of processors as the characteristic size of logic gates (or transistors) gets smaller and smaller. In this article, we consider the problem of assigning processing frequencies to a group of periodic real-time tasks so as to minimize the overall energy consumption under the constraints of time and reliability. First, under the DVS, we take the reliability of the ESs into consideration through the regularization terms and present the energy consumption optimization model based on the metaheuristic algorithms. Second, a novel algorithm for adaptive differential whale swarm optimization (ADWOA) is proposed according to the optimization requirements. Finally, the optimized data are saved on the chain through the storable feature of the blockchain for the necessary queries. It is worth noting that the on-chain data contains the intrinsic characteristics of the ES, which may give rise to the disclosure of processor privacy. Therefore, we come up with the differential privacy on-chain creating algorithm (DPCA) to protect the privacy of data on the chain. Experimental results show that ADWOA can minimize the energy consumption in real-time ES on the premise of ensuring system reliability and privacy.

As one of the key technologies to enable the internet of things (IoT), cloud computing plays a significant role in providing huge computing and storage facilities for large-scale data. Though cloud computing brings great advantages, new issues emerge, such as data security breach and privacy disclosure. In this paper, we introduce a novel secure and privacy-preserving outsourcing computing scheme (hereafter referred to as SPOCS) to tackle this issue. In SPOCS, the effective use of Intel SGX, one of the trusted execution environment (TEE), ensures the confidence and integrity of sensitive data in cloud computing and prevents data loss from causing privacy disclosure. In order to keep malicious cloud service providers (CSPs) from illegally tampering with the outsourcing results, blockchain is employed to ensure the data immutability. Significantly, our proposed scheme achieves anonymity and traceability. In the outsourcing process, smart contracts are applied to make the whole process fully automated without any human involvement. Finally, the security of the proposed scheme is analyzed in terms of its resistance to different attacks. The experiments indicate that our scheme is effective and efficient.

Smart home systems are both technologically and economically advancing rapidly. As people become gradually inalienable to smart home infrastructures, their security conditions are getting more and more closely tied to everyone's privacy and safety. In this paper, we consider smart apps, either malicious ones with evil intentions or benign ones with logic errors, that can cause property loss or even physical sufferings to the user when being executed in a smart home environment and interacting with human activities and environmental changes. Unfortunately, current preventive measures rely on permission-based access control, failing to provide ideal protections against such threats due to the nature of their rigid designs. In this paper, we propose CommandFence, a novel digital-twin-based security framework that adopts a fundamentally new concept of protecting the smart home system by letting any sequence of app commands to be executed in a virtual smart home system, in which a deep-q network (DQN) is used to predict if the sequence could lead to a risky consequence. CommandFence is composed of an Interposition Layer to interpose app commands and an Emulation Layer to figure out whether they can cause any risky smart home state if correlating with possible human activities and environmental changes. We fully implemented our CommandFence implementation and tested against 553 official SmartApps on the Samsung SmartThings platform and successfully identified 34 potentially dangerous ones, with 31 of them reported to be problematicAuthor: Please provide index terms/keywords for your article. To download the IEEE Taxonomy go tohttp://www.ieee.org/documents/taxonomy_v101.pdf?> the first time to our best knowledge. Moreover, We tested our CommandFence on the 10 malicious SmartApps created by Jiaet al.2017, and successfully identified 7 of them as risky, with the missed ones actually only causing smartphone information leak (not harmful to the smart home system). We also tested CommandFence against the 17 benign SmartApps with logic errors developed by Celiket al.2017, and achieved a 100% accuracy. Our experimental studies indicate that adopting CommandFence incurs a neglectable overhead of 0.1675 seconds.

Training machine learning models in a decentralized way has attracted tremendous attention on intelligent Internet of Vehicles (IIoV). However, it is highly dynamic and asymmetric for the connections between vehicles in IIoV due to the mobility of vehicles and the complex communication environment, which poses great challenges on designing efficient distributed learning algorithms. To address this problem, we focus on the basic stochastic gradient descent (SGD) algorithm and propose a decentralized parallel SGD algorithm (DPSGD-WB) for the complex IIoV. The algorithm is based on weight-balancing to overcome the difficulty caused by the dynamic and asymmetric connectivity in IIoV. With rigorous analysis, we show that DPSGD-WB converges on the optimal rate of$O(1/\sqrt {Kn})$, where$n$is the number of vehicle terminals and$K$is the number of iterations. To the best of our knowledge, our proposed algorithm is the first known decentralized parallel SGD algorithm that can be implemented in asymmetric and dynamic intelligent IoV systems. Finally, extensive experiments demonstrate the efficacy of our algorithm.

Differential privacy provides strong privacy preservation guarantee in information sharing. As social network analysis has been enjoying many applications, it opens a new arena for applications of differential privacy. This article presents a comprehensive survey connecting the basic principles of differential privacy and applications in social network analysis. We concisely review the foundations of differential privacy and the major variants. Then, we discuss how differential privacy is applied to social network analysis, including privacy attacks in social networks, models of differential privacy in social network analysis, and a series of popular tasks, such as analyzing degree distribution, counting subgraphs and assigning weights to edges. We also discuss a series of challenges for future work.

A large amount of high-dimensional and heterogeneous data appear in practical applications, which are often published to third parties for data analysis, recommendations, targeted advertising, and reliable predictions. However, publishing these data may disclose personal sensitive information, resulting in an increasing concern on privacy violations. Privacy-preserving data publishing has received considerable attention in recent years. Unfortunately, the differentially private publication of high dimensional data remains a challenging problem. In this paper, we propose a differentially private high-dimensional data publication mechanism (DP2-Pub) that runs in two phases: a Markov-blanket-based attribute clustering phase and an invariant post randomization (PRAM) phase. Specifically, splitting attributes into several low-dimensional clusters with high intra-cluster cohesion and low inter-cluster coupling helps obtain a reasonable allocation of privacy budget, while a double-perturbation mechanism satisfying local differential privacy facilitates an invariant PRAM to ensure no loss of statistical information and thus significantly preserves data utility. We also extend our DP2-Pub mechanism to the scenario with a semi-honest server which satisfies local differential privacy. We conduct extensive experiments on four real-world datasets and the experimental results demonstrate that our mechanism can significantly improve the data utility of the published data while satisfying differential privacy.

In this article, we study a distributed privacy-preserving learning problem in social networks with general topology. The agents can communicate with each other over the network, which may result in privacy disclosure, since the trustworthiness of the agents cannot be guaranteed. Given a set of options which yield unknown stochastic rewards, each agent is required to learn the best one, aiming at maximizing the resulting expected average cumulative reward. To serve the above goal, we propose a four-staged distributed algorithm which efficiently exploits the collaboration among the agents while preserving the local privacy for each of them. In particular, our algorithm proceeds iteratively, and in every round, each agent i) randomly perturbs its adoption for the privacy-preserving purpose, ii) disseminates the perturbed adoption over the social network in a nearly uniform manner through random walking, iii) selects an option by referring to the perturbed suggestions received from its peers, and iv) decides whether or not to adopt the selected option as preference according to its latest reward feedback. Through solid theoretical analysis, we quantify the trade-off among the number of agents (or communication overhead), privacy preserving and learning utility. We also perform extensive simulations to verify the efficacy of our proposed social learning algorithm.

This paper initiates the study for the basic primitive of distributed message dissemination in multi-hop wireless networks under a strong adversarial jamming model. Specifically, the message dissemination problem is to deliver a message initiating at a source node to the whole network. An efficient algorithm for message dissemination can be an important building block for solving a variety of high-level network tasks. We consider the hard non-spontaneous wakeup case, where a node only wakes up when it receives a message. Under the realistic SINR model and a strong adversarial jamming model that removes the budget constraint commonly adopted in previous work by the adversary, we present a distributed randomized algorithm that can accomplish message dissemination in$\mathscr{T}(O(D(\log n+\log R)))$time slots with a high probability performance guarantee, where$\mathscr{T}(U)$is the number of time slots in the interval from the beginning of the algorithm's execution that contains U unjammed time slots, n is the number of nodes in the network, D is the network diameter,$R$is the distance with respect to which the network is connected. Our algorithm is shown to be almost asymptotically optimal by lower bound$\Omega(D\log n)$for non-spontaneous message dissemination in networks without jamming.

Public clouds have drawn increasing attention from academia and industry due to their high computational and storage performance. Attribute-based encryption (ABE) is the most promising technology to simultaneously achieve confidentiality and fine-grained access control of the cloud-stored data. However, traditional ABE that relies on centralized authority faces several key management issues, such as the key escrow, key distribution, key tracking, key update, and heavy communication and computing overhead for users, which will cause security concerns and impede its widespread application. On the other hand, blockchain technology preserves distributed ledgers to ensure the immutability and transparency of data, which can further solve the security vulnerabilities caused by system centralization. This paper proposes a blockchain-assisted transformation method to solve all the key management problems mentioned above in ciphertext-policy ABE by utilizing technologies such as secret sharing protocols. In addition, our transformation method realizes two additional benefits: outsourced decryption and efficient user revocation, which are extremely valuable for practical implementations. We simulate a demonstration by adopting the most popular permissioned blockchain, Hyperledger Fabric. The security and efficiency analysis reveals that the scheme obtained from our transformation method can achieve replayable chosen-ciphertext security with extremely efficient decryption.

Internet of Things (IoT) is rapidly spreading and reaching a multitude of different domains, since the fifth generation (5G) wireless technologies are the key enablers of many IoT applications. It is hence apparent that the broadcast nature of IoT devices makes data security unprecedentedly critical. Compared with traditional cryptography algorithms, which cannot cater for the features of IoT devices characterized by the severe limits in terms of energy, computation and storage capabilities, physical layer security (PLS) has been regarded as a promising solution to facilitate secure communications by exploiting the intrinsic randomness of the wireless medium. However, most of previous works assumed that all devices are static, and the impact of mobility on PLS deserves further investigation. In this paper, applying two types of random mobile models, i.e., the models of Random WayPoint (RWP) and Random Direction (RD), we study the impact of mobility on PLS in a scenario with three types of wireless devices (i.e., a destination, multiple interferers and an eavesdropper). Specifically, we establish an analytical framework for secrecy transmission capacity (STC), a fundamental metric in the study of PLS, under RWP and RD models. To the best of our knowledge, this is the first paper to derive STC and present the condition to achieve a positive STC with the consideration of mobility. We conclude that the RWP mobile destination can achieve a higher STC than that achievable in RD mobile and static scenarios, while RWP mobile eavesdropper is a challenging scenario to obtain a positive STC. Therefore, we propose an effective secrecy improvement strategy for the latter. Simulation validates the theoretical analyses.

In traditional networks, the multicast tree packing solutions usually aim to minimize the overall multicast tree cost, which can effectively improve network accommodation capacity but is disadvantageous to fully use network resources. In this article, we propose a delay-optimized multicast tree packing problem called delivery delay minimized multicast tree packing (DDMMTP), which aims to minimize the average source-destination delay, under constraints on the bandwidth and maximum source-destination delay, according to available network resources. A low source-destination delay is desirable because it improves the service quality, especially for time-sensitive applications. In practice, the DDMMTP is highly valuable for the software-defined network (SDN) mainly because this new network paradigm has the ability to rapidly rearrange multicast routes on demand. The DDMMTP problem is NP-hard. We solve it approximately by a batched multicast tree packing algorithm and a network accommodation capacity improvement algorithm that adjusts existing multicast paths on demand. We also propose a source-destination delay improvement algorithm to further reduce source-destination delays based on new available network resources.

Remote sensing image scene classification is to label remote sensing images as a specific scene category by understanding the semantic information of the images. It is an essential link in remote sensing image analysis and interpretation and has important research value. Convolutional neural networks (CNNs) have been dominant in remote sensing image scene classification due to their powerful feature extraction capabilities. The general trend has been to make deeper and wider CNN architectures to achieve higher classification accuracy. However, these advances to improve accuracy enlarge the network, creating too many parameters and high computational costs. Large models are difficult to deploy on resource-constrained edge devices for practical applications. Furthermore, CNNs can effectively capture local information but are weak in extracting global features. To overcome these drawbacks, we propose a novel knowledge distillation (KD) based method by employing Swin Transformer as a teacher network for guiding MobileNetV2 with Parameter-Free Attention (MobileNetV2-PFA). First, we modify MobileNetV2 by introducing PFA into the inverted bottleneck block; this improvement helps the model learn more latent and robust features without extra parameters. Second, Swin Transformer is an excellent architecture for capturing long-range dependencies via shifted window-based attention. So, we utilize the long-range dependency information from the Swin Transformer to assist MobileNetV2-PFA training through KD. Experimental results on the challenging NWPU-RESISC45 dataset show that the proposed method outperforms the original MobileNetV2 in classification accuracy with low computational consumption.

Sensing human activity via WiFi Channel State Information (CSI) has considerable application prospects in future intelligent interaction scenarios such as virtual reality, intelligent games, metaverse, etc. Recently, many Deep Learning-based WiFi sensing schemes have been proposed in the literature, which gained high accuracy for a wide range of simple activities such as standing, squatting, and bending. However, the performance will be suffered when existing approaches are used to recognize drastic activities, such as actions in vigorous sports. This is mainly due to the reason that the spatiotemporal information of these actions is not well utilized. To overcome this drawback, we propose a novel DL-based WiFi sensing method for drastic activity recognition by combining the Convolutional Neural Network (CNN) and the Bidirectional Long Short-Term Memory (BiLSTM) network. The designed CNN-BiLSTM architecture is in parallel with feature extraction, which can simultaneously extract sufficient spatiotemporal features of action data and establish the mapping relationship between actions and CSI streams, thereby improving the accuracy of activity recognition. The CNN is used to extract information on the spatial dimension, while the BiLSTM extracts information on the time dimension. To verify the performance of the proposed scheme, we build a hardware experiment platform and constrain a dataset with 1400 pieces of records for 7 classes of basketball actions. After training over the dataset, the proposed CNN-BiLSTM scheme achieves 96% experimental accuracy on the test set, which is better than the benchmark methods.

Generative Adversarial Networks (GANs) have been used in the field of speech enhancement due to their huge potentials in reducing the noise mixed in the signals. Most of existing GAN-based speech enhancement approaches either operate on time domain or exploit the magnitude spectra in time-frequency domain, but lack consideration of direct optimization of the phase. In this paper, we propose a GAN architecture for speech enhancement based on gated linear units (GLUs) and Dual-Path Transformers (DPTs), which simultaneously deals with the amplitude and phase information on the time-frequency domain. The generator of the proposed GAN architecture is designed following an autoencoder structure fed by the real and imaginary parts of the time-frequency frames. The encoder of the generator is constructed by multiple cascaded convolutional GLUs (ConvGLUs), while the decoder consists of two groups of cascaded deconvolutional GLUs (DeconvGLUs), one for the real part of the spectrogram and the other for the imaginary part. The GLUs are adopted since they are potential in avoiding the gradient vanishing issue dwelling in deep architectures by providing a linear path for the gradients while retaining non-linear capabilities. Aiming at capturing the long-range dependent features in speech, we place DPTs between the encoder and the decoder of the generator, which contains multi-head attention modules and Bi-directional Gated Recurrent Units (BiGRUs). Moreover, the DPT structure is also merged with multiple one-dimensional convolutional layers in the discriminator of the GAN. Such a design not only improves the speech enhancement performance of GAN by focusing on multiple features of speech, but also reducing the volume of model parameters of GAN. Experimental results suggest that the proposed GAN architecture outperforms the existing benchmark GANs in terms of both objective speech intelligibility and quality with less computational complexity.

Abstract Remote sensing scene classification aims to automatically assign a specific semantic label to each image. It is challenging to classify remote sensing scene images due to the images' diversity and rich spatial information. Recently, convolutional neural networks have been widely used to overcome these difficulties, such as the famous Visual Geometry Group (VGG) network. However, the VGG network with local receptive fields cannot model the global information of remote sensing images well. It also needs a large number of parameters and floating point operations to achieve satisfactory accuracy. To overcome these challenges, we introduce the self‐attention mechanism to the VGG network. Specifically, we replace the last four convolutional layers in the VGG‐19 network with two cascaded self‐attention blocks, each consisting of two multi‐head self‐attention (MHSA) layers with the residual network structure. The new structure can simultaneously explore the local and global information from remote sensing scenes. Such improvements not only reduce model parameters but also improve the classification performance. The effectiveness of the proposed method is validated through experiments on four public data sets, i.e., NaSC‐TG2, WHU‐RS19, AID and EuroSAT.

Abstract In the medical image analysis domain, medical image segmentation has a significant impact on the quantitative analysis of organ or tissue function, as the first and critical component of diagnosis and treatment pipeline. In this paper, a dense R‐CNN segmentation model based on dual‐attention are proposed for medical images multi‐target instance segmentation. The model combines channel and spatial attention mechanism to extract image features and fuse multi‐scale feature information hierarchically. It combines up‐sampling strategies such as dilated convolution and bilinear interpolation to strengthen the distinguishability between multi‐target instances and pixel‐level features in other regions. The multi‐target detection mechanism of R‐CNN is combined with the multi‐scale feature extraction and fusion ability of dense convolution network. In the encoding stage, the multi‐scale hybrid bottleneck module and deformable convolution are introduced to extract more accurate structural feature information and increase the receptive‐field. In the decoding stage, the bilinear interpolation and the adaptive hierarchical fusion mechanism are used to strengthen the distinguishability between the target region and other regions, and improve the accuracy of instance segmentation. Taking cardiac MRI segmentation as an example, the left and right ventricles, and left ventricular myocardium are selected as segmentation targets. The pixel accuracy is 90.82%, the class pixel accuracy is 87.91%, the mean intersection‐over‐union is 81.52%, the Dice coefficient is 89.82%, and Hausdorff distance is 9.2, which is improved compared with other methods. It verifies the accuracy and applicability of the proposed method for multi‐target instance segmentation of medical images.

As one of the most widely used applications of the Internet of Things (IoT), intelligent transportation system (ITS) is of great significance for urban traffic planning, traffic control, and traffic guidance. However, widespread traffic congestion occurs with the increased number of vehicles. The traffic flow prediction is a good idea for traffic congestion. Therefore, many schemes have been proposed for accurate and real-time traffic flow prediction, but there still exist many issues, including low accuracy, weak adaptability and inferior real-time. Meanwhile, the complex spatial and temporal dependencies in traffic flow are still challenging. To address the above issues, we propose a novel spatial-temporal Chebyshev graph neural network model (ST-ChebNet) for traffic flow prediction to capture the spatial-temporal features, which can ensure accurate traffic flow prediction. Concretely, we first add a fully connected layer to fuse the features of traffic data into a new feature to generate a matrix, and then the long short-term memory (LSTM) model is adopted to learn traffic state changes for capturing the temporal dependencies. Then, we use the Chebyshev graph neural network (ChebNet) to learn the complex topological structures in the traffic network for capturing the spatial dependencies. Eventually, the spatial features and the temporal features are fused to guarantee the traffic flow prediction. The experiments show that ST-ChebNet can make accurate and real-time traffic flow prediction compared with other eight baseline methods on real-world traffic data sets PeMS.

Blockchain creates a secure environment on top of strict cryptographic assumptions and rigorous security proofs. It permits on-chain interactions to achieve trustworthy properties such as traceability, transparency, and accountability. However, current blockchain trustworthiness is only confined to on-chain, creating a “trust gap” to the physical, off-chain environment. This is due to the lack of a scheme that can truthfully reflect the physical world in a real-time and consistent manner. Such an absence hinders further blockchain applications in the physical world, especially for the security-sensitive ones. In this paper, we propose a framework to extend blockchain trust from on-chain to off-chain, and take trustworthy vaccine tracing as an example scheme. Our scheme consists of 1) a Trusted Execution Environment (TEE)-enabled trusted environment monitoring system built with the Arm Cortex-M33 microcontroller that continuously senses the inside of a vaccine box through trusted sensors and generates anti-forgery data; and 2) a consistency protocol to upload the environment status data from the TEE system to blockchain in a truthful, real-time consistent, continuous and fault-tolerant fashion. Our security analysis indicates that no adversary can tamper with the vaccine in any way without being captured. We carry out an experiment to record the internal status of a vaccine shipping box during transportation, and the results indicate that the proposed system incurs an average latency of 84 ms in local sensing and processing followed by an average latency of 130 ms to have the sensed data transmitted to and been available in the blockchain.

Blockchain technologies can enable secure computing environments among mistrusting parties. Permissioned blockchains are particularly enlightened by companies, enterprises, and government agencies due to their efficiency, customizability, and governance-friendly features. Obviously, seamlessly fusing blockchain and cloud computing can significantly benefit permissioned blockchains; nevertheless, most blockchains implemented on clouds are originally designed for loosely-coupled networks where nodes communicate asynchronously, failing to take advantages of the closely-coupled nature of cloud servers. In this paper, we propose an innovative cloud-oriented blockchain -- CloudChain, which is a modularized three-layer system composed of the network layer, consensus layer, and blockchain layer. CloudChain is based on a shared-memory model where nodes communicate synchronously by direct memory accesses. We realize the shared-memory model with the Remote Direct Memory Access technology, based on which we propose a shared-memory consensus algorithm to ensure presistence and liveness, the two crucial blockchain security properties countering Byzantine nodes. We also implement a CloudChain prototype based on a RoCEv2-based testbed to experimentally validate our design, and the results verify the feasibility and efficiency of CloudChain.

Online social networks have gained tremendous popularity and have dramatically changed the way we communicate in recent years. However, the publishing of social network data raises more and more privacy concerns. To protect user privacy, social networking data are usually anonymized before being released. Nevertheless, existing anonymization techniques do not have sufficient protection effects. A large number of deanonymization attacks have arisen, and they mainly make use of either network topology or node attribute information to successfully reidentify anonymized users. In this article, we model a social network as a structure-attribute network (SAN) integrating the structural characteristics and the attribute information associated with social network users. A novel similarity measurement of social network nodes is proposed by considering the structural similarity and attribute similarity. A two-phase scheme is then designed to perform deanonymization by first dividing a social network (graph) into smaller subgraphs based on spectral graph partitioning and then applying the proposed deanonymization algorithm on each matched subgraph pair. We simulate the deanonymization attack with extensive experiments on three real-world datasets, and the experimental results demonstrate that our approach can improve the accuracy and time complexity of deanonymization compared with the state of the art.

This article studies the core maintenance problem in dynamic graphs. The core number is a fundamental index reflecting the cohesiveness of a graph, which is widely used in large-scale graph analytics. The core maintenance problem requires updating the core numbers of vertices after a set of edges and vertices are inserted into or deleted from the graph. Previous works focus on the scenario of single-edge updates and process the edges one by one when multiple edges are inserted/deleted. We initiate the studies of processing multiple edges concurrently to improve the efficiency of core maintenance. Specifically, we discover a structure of inserted/deleted edges,superior edge set, which can be processed together to greatly reduce unnecessarily repeated visits of vertices in the procedure of sequential edge processing. Based on the structure of the superior edge set, efficient algorithms are then devised for incremental and decremental core maintenance, respectively. Compared with single-edge processing algorithms, our algorithms show a significant speedup in the processing time. Furthermore, our algorithms admit parallel implementations, which can further improve the update efficiency. We also conduct extensive experiments on different types of real-world, temporal, and synthetic data sets, and the results illustrate that the proposed algorithms exhibit good efficiency, stability, and scalability.

Radio frequency identification (RFID) systems have achieved wide applications in various scenarios, such as warehouse management, logistic tracking, smart transportation, etc. Despite the enormous benefits from the RFID systems, the security issues are still of great concern, such as the cloning attacks. In this article, we focus on the detection of probabilistic cloning attacks for the anonymous RFID systems, in which each cloned genuine tag suffers attacks from its clone tags with a certain probability. We propose an efficient detection protocol against the probabilistic cloning attacks in anonymous RFID systems named DAP, which can detect the probabilistic cloning attacks with the required detection reliability$\alpha$if at least one tag is attacked with the probability no less than the threshold$P_T$. The proposed DAP protocol fully utilizes the inconsistency and unreconcilable collision caused by the probabilistic cloning attacks to effectively detect the probabilistic cloning attacks.The parameters are theoretically analyzed to maximize the detection efficiency. The extensive simulations are conducted and the results demonstrate the effectiveness of the proposed DAP protocol.

This article studies decentralized federated learning algorithms in wireless IoT networks. The traditional parameter server architecture for federated learning faces some problems such as low fault tolerance, large communication overhead and inaccessibility of private data. To solve these problems, we propose a decentralized wireless federated learning algorithm called DWFL. The algorithm works in a system where the workers are organized in a peer-to-peer and server-less manner, and the workers exchange their privacy preserving data with the analog transmission scheme over wireless channels in parallel. With rigorous analysis, we show that DWFL satisfies$(\epsilon,\delta)$-differential privacy and the privacy budget per worker scales as$\mathcal {O}(\frac{1}{\sqrt{N}})$, in contrast with the constant budget in the orthogonal transmission approach. Furthermore, DWFL converges at the same rate of$\mathcal {O}(\sqrt{\frac{1}{TN}})$as the best known centralized algorithm with a central parameter server. Extensive experiments demonstrate that our algorithm DWFL also performs well in real settings.

This article addresses the problem of fault-tolerant consensus control of a general nonlinear multiagent system subject to actuator faults and disturbed and faulty networks. By using neural network (NN) and adaptive control techniques, estimations of unknown state-dependent boundaries of nonlinear dynamics and actuator faults, which can reflect the worst impacts on the system, are first developed. A novel NN-based adaptive observer is designed for the observation of faulty transformation signals in networks. On the basis of the NN-based observer and adaptive control strategies, fault-tolerant consensus control schemes are designed to guarantee the bounded consensus of the closed-loop multiagent system with disturbed and faulty networks and actuator faults. The validity of the proposed adaptively distributed consensus control schemes is demonstrated by a multiagent system composed of five nonlinear forced pendulums.

This paper studies joint beamforming problems for an intelligent reflecting surface (IRS)-aided multi-cell multiple-input single-output (MISO) system, and the goal is to maximize the sum rate by jointly optimizing the transmit beamforming vectors at BSs and the reflective beamforming vector at the IRS, subject to the individual maximum transmit power constraints at BSs, and the reflection constraints at the IRS. Due to the formulated optimization problem is highly non-convex, we propose an alternating optimization (AO) algorithm based on successive convex approximation (SCA) such that the transmit and reflective beamforming vectors can be optimized alternately. We further consider the SINR balancing beamforming design scheme by maximizing the minimum SINR among all users to enhance the fairness among users, in which the transmit and reflective beamforming vectors are optimized in an alternating manner. The transmit beamforming vectors are optimized by the second-order-cone programming (SOCP) based on bisection method and the reflective beamforming vector is updated based on the technique of semidefinite relaxation (SDR). Simulation results show that the two proposed algorithms considerably outperform the benchmark zero-forcing (ZF) scheme. Moreover, the AO algorithm based on SCA has good communication performance than the other two schemes. And the AO algorithm based on bisection search guarantees the fairness for all users.

Emerging applications impose the min-max line barrier coverage (LBC) problem that aims to minimize the maximum movement of the sensors for the sake of balancing energy consumption. In the paper, we devise an algorithm for LBC that finds an optimal solution within a runtime$O(n^{2})$, improving the previous state-of-art runtime$o(n^{2}\log n)$due to [7]. The key idea to accelerating the computation of the optimum solutions is to use approximation solutions that are obtained by our devised approximation algorithm. Numerical experiments demonstrate our algorithms outperform all the other baselines including the previous state-of-art algorithm.

As a fundamental task in natural language processing, sentence semantic matching (SSM) is critical yet challenging due to difficulties in learning expressive sentence representation while capturing complex interactions between sentences. Recent work has shown the great potential of deep neural models in improving the performance of SSM task. However, existing work usually employs recurrent neural networks (RNNs) or 1D (one-dimensional) convolutional neural networks (CNNs) to learn sentence representation, leading to limited performance improvement. Benefiting from the multi-dimensional structure, 2D convolutional neural networks are expected to be more powerful to learn expressive sentence representation by capturing the implicit inter-sentence interactions and thus can further improve the performance of SSM. To this end, in this paper, we propose a novel sentence semantic matching model named Hierarchical CNN based on Dimension-augmented Representation (HiDR). In HiDR, first, bidirectional long short-term memory networks (LSTMs) are utilized to generate dimension-augmented representation for each of the input sentences; then, a hierarchical 2D CNN is devised to learn sentence representation while capturing the inter-sentence interactions, followed by a prediction layer based on sigmoid function to output the matching degree between sentences. To evaluate the performance of our proposed model, we conducted extensive experiments on two public real-world data sets. The empirical results show that HiDR has achieved remarkable results, which demonstrates either better or comparable performance w.r.t. BERT-based models.

Chinese semantic matching is a fundamental task in natural language processing, which is critical and yet challenging for a series of downstream tasks. Although recent work on text representation learning has shown its potential in improving the performance on semantic matching, relatively limited work has been done on exploring the relevant interactive information between two granularity of Chinese text, i.e., character and word. Existing methods usually focus on capturing the interactive features from single granularity, which lead to inefficient text representation. Also, they typically fail to consider the fusion of features from different granularity. As a result, they only achieve limited performance improvement. This paper proposes a novel Chinese semantic matching model based on multi-granularity alignment and feature fusion (MAFFo). To be specific, we first encode the texts from different granularity, which are further handled with soft-alignment attention mechanism to extract relevant interactive information between texts on different granularity. In addition, we devise a feature fusion structure to merge the features from different granularity to generate an ideal representation for the pair of input text sequences, followed by a sigmoid function to judge the semantic matching degree. Extensive experiments on the publicly available dataset BQ demonstrate that our model can effectively improve the performance of semantic matching task and achieve comparable performance with BERT-based methods.

The pool-hopping attack casts down the expected profits of both the mining pool and honest miners in Blockchain. The mainstream countermeasures, namely PPS (pay-per-share) and PPLNS (pay-per-last-N-share), can hedge pool hopping but need to charge miners some fees when they join in a pool. Obviously, the higher fee charged, the higher cost of joining the pool, the less motivation of a miner to mine in the pool. In this article, we apply the zero-determinant (ZD) theory to design a novel pooled mining which offers an incentive mechanism for motivating miners not to switch in pools strategically by economic means without fee charged. In short, the proposed pooled mining has three unique features: 1) fee-free. No fee is charged if the miner does not hop, 2) wide applicability. It can be employed in both prepaid and postpaid mechanisms, and 3) fairness. Even can dominate the game with any miner, a pool has to cooperate when a miner does not hop among pools, implying that the pool cannot squeeze the honest miners financially. The fairness of our scheme makes it have long-term sustainability. Both theoretical analyses and numerical simulations demonstrate the effectiveness of our scheme.

Radio-Frequency Identification (RFID) is an emerging technology which has been widely applied in various scenarios, such as tracking, object monitoring, and social networks, etc. Cloning attacks can severely disturb the RFID systems, such as missed detection for the missing tags. Although there are some techniques with physical architecture design or complicated encryption and cryptography proposed to prevent the tags from being cloned, it is difficult to definitely avoid the cloning attack. Therefore, cloning attack detection and identification are critical for the RFID systems. Prior works rely on that each clone tag will reply to the reader when its corresponding genuine tag is queried. In this article, we consider a more general attack model, in which each clone tag replies to the reader's query with a predefined probability, i.e., attack probability. We concentrate on identifying the tags being attacked with the probability no less than a threshold $P_{t}$ with the required identification reliability $\alpha $ . We first propose a basic protocol to Identify the Probabilistic Cloning Attacks with required identification reliability for the large-scale RFID systems called IPCA. Then we propose two enhanced protocols called MS-IPCA and S-IPCA respectively to improve the identification efficiency. We theoretically analyze the parameters of the proposed IPCA, MS-IPCA and S-IPCA protocols to maximize the identification efficiency. Finally we conduct extensive simulations to validate the effectiveness of the proposed protocols.

The growing threat of personal data breach in data trading pinpoints an urgent need to develop countermeasures for preserving individual privacy. The state-of-the-art work either endows the data collector with the responsibility of data privacy or reports only a privacy-preserving version of the data. The basic assumption of the former approach that the data collector is trustworthy does not always hold true in reality, whereas the latter approach reduces the value of data. In this paper, we investigate the privacy leakage issue from the root source. Specifically, we take a fresh look to reverse the inferior position of the data provider by making her dominate the game with the collector to solve the dilemma in data trading. To that aim, we propose the noisy-sequentially zero-determinant (NSZD) strategies by tailoring the classical zero-determinant strategies, originally designed for the simultaneous-move game, to adapt to the noisy sequential game. NSZD strategies can empower the data provider to unilaterally set the expected payoff of the data collector or enforce a positive relationship between her and the data collector's expected payoffs. Both strategies can stimulate a rational data collector to behave honestly, boosting a healthy data trading market. Numerical simulations are used to examine the impacts of key parameters and the feasible region where the data provider can be an NSZD player. Finally, we prove that the data collector cannot employ NSZD to further dominate the data market for deteriorating privacy leakage.

Dynamicity is one of the most challenging, yet, key aspects of wireless networks. It can come in many guises, such as churn (node insertion/deletion) and node mobility. Although the study of dynamic networks has been popular in distributed computing domain, previous works considered only partial factors causing dynamicity. In this work, we propose a dynamic model that is comprehensive to include crucial dynamic factors on nodes and links. Our model defines dynamicity in terms of localized topological changes in the vicinity of each node, rather than a global view of the whole network. Obviously, a localized dynamic model suits distributed algorithm studies better than a global one. The proposed dynamic model makes use of the more realistic SINR model to describe wireless interference, instead of the oversimplified graph-based models adopted by most existing research. Under the proposed dynamic model, we develop an efficient distributed algorithm accomplishing local broadcast services in the abstract MAC layer that was first presented by Kuhnet al.[24]. Our solution paves the way for many new fast algorithms to solve high-level problems in dynamic networks, such as consensus, single-message broadcast, and multiple-message broadcast. Extensive simulation studies indicate that our algorithm exhibits good performance in realistic environments with dynamic network behaviors.

Many applications such as smart metering and location based services pose strong privacy requirements but achieving privacy protection at the client side is a non-trial problem as payment for the services must be computed by the server at the end of each billing period. In this paper, we propose a privacy preservation and billing scheme termed PPDIR based on delayed information release. PPDIR relies on a novel group signature mechanism and the asymmetric Rabin cryptosystem to protect the privacy of the clients and their requests, to achieve accountability and non-repudiation, and to shift the computational complexity to the server side. It adopts a secret token for anonymity and the token is updated for each client at the beginning of each billing period and securely released only to the server at the end of the billing period. Such a strategy can prevent the server from linking a client's requests made at different billing periods. It also prevents any adversary from linking any request to any client. Note that the server is able to figure out all requests made by a client within a billing period after receiving the delayed token, which is unavoidable for billing purpose. We prove the security properties of the group signature scheme, and analyze the security strength of PPDIR. Our study indicates that PPDIR can achieve privacy-preservation, confidentiality, non-repudiation, accountability, and other security objectives. We also evaluate the performance of our scheme in terms of communication and computational overheads.

Link scheduling is an appealing solution for ensuring the reliability and latency requirements of Internet of Things (IoT). Most existing results on the link scheduling problem were based on the graph or SINR (Signal-to-Interference-plus-Noise-Ratio) models, which ignored the impact of the random fading gain of the signals strength. In this paper, we address the link scheduling problem under the Rayleigh fading model. Both Shortest Link Scheduling (SLS) and Maximum Link Scheduling (MLS) problems are studied. In particular, we show that a set of links can be activated simultaneously under Rayleigh fading model if all link SINR constraints are satisfied. Based on the analysis of previous Link Diversity Partition (LDP) algorithm, we propose an Improved LDP (ILDP) algorithm and a centralized algorithm by localizing the global interference (denoted by CLT), building on which we design a distributed CLT algorithm (denoted by RCRDCLT) that converges to a constant approximation factor of the optimum with the time complexity of$O(\ln n)$, where$n$is the number of links. Furthermore, executing repeatedly RCRDCLT can solve the SLS with an approximation factor of$\Theta (\ln n)$. Extensive simulations indicate that CLT is more effective than previous six popular link scheduling algorithms, and RCRDCLT has the lowest time complexity while only losses a constant fraction of the optimum schedule.

In this paper, we investigate distributed broadcasting in dynamic networks, where the topology changes continually over time. We propose a network model that captures the dynamicity caused by both churn and mobility of nodes. In contrast to existing work on dynamic networks, our model defines the dynamicity in terms of localized topological changes in the vicinity of each node, rather than a global view of the whole network. Obviously, a local dynamic model suits distributed algorithms better than a global one. The proposed dynamic model uses the more realistic SINR model to depict wireless interference, instead of oversimplified graph-based models adopted in most existing work. We consider the fundamental communication primitive of global broadcast, which is to disseminate a message from a source node to the whole network. Specifically, we present a randomized distributed algorithm that can accomplish dynamic broadcasting in an asymptotically optimal running time of$O(D_{T})$with a high probability guarantee, under the assumption of reasonably constantdynamicity rate, where$D_{T}$is thedynamic diameter, a parameter proposed to depict the complexity of dynamic broadcasting. We believe our local dynamic model can greatly facilitate distributed algorithm studies in mobile and dynamic wireless networks.

The byzantine model is widely used to depict a variety of node faults in networks. Previous studies on byzantine-resilient protocols in wireless networks assume reliable communications and do not consider the jamming behavior of byzantine nodes. Such jamming, however, is a very critical and realistic behavior to be considered in modern wireless networks. In this paper, for the first time, we integrate the jamming behavior of byzantine nodes into the network setting. We show that, in this much more comprehensive and harsh model, efficient distributed communication protocols can be still devised with elaborate protocol design. In particular, we developed an algorithm that can accomplish the basic multiple-message dissemination task close to the optimal solution in terms of running time. Empirical results validate the byzantine-resilience and efficiency of our algorithm.

This paper presents$\mathit {wChain}$, a blockchain protocol specifically designed for multihop wireless networks that deeply integrates wireless communication properties and blockchain technologies under the realistic SINR model. We adopt a hierarchical spanner as the communication backbone to address medium contention and achieve fast data aggregation within$O(\log N\log \Gamma)$slots where$N$is the network size and$\Gamma $refers to the ratio of the maximum distance to the minimum distance between any two nodes. Besides,$\mathit {wChain}$employs data aggregation and reaggregation as well as node recovery mechanisms to ensure efficiency, fault tolerance, persistence, and liveness. The worst-case runtime of$\mathit {wChain}$is upper bounded by$O(f\log N\log \Gamma)$, where$f=\lfloor \frac {N}{2} \rfloor $is the upper bound of the number of faulty nodes. To validate our design, we conduct both theoretical analysis and simulation studies. The results not only demonstrate the nice properties of$\mathit {wChain}$, but also point to a large new space for the exploration of blockchain protocols in wireless networks.

In this paper, we study distributed algorithms to realize efficient communications under the Rayleigh-fading model. This model extends the popular deterministic SINR model using stochastic propagations to address the fading effects observed in reality. Stochastic propagations can greatly increase the difficulty of handling interference and collisions, especially in a local context without much global knowledge. We present a new technique called Inductive Coloring that can be used to schedule fast transmissions with Rayleigh-fading interference. The computation of inductive coloring takes only O(log2n) time with the proposed distributed algorithm, where n is the number of nodes in the network. We illustrate the power of inductive coloring by giving a distributed and randomized algorithm to implement the abstract MAC (absMAC) layer, which was first proposed by Kuhn et al.. With two basic time-guaranteed communication primitives, namely acknowledgement and progress, which correspond to the operations of node local broadcasts and message receptions from others, the absMAC layer decomposes the algorithm design and analysis in networks into two independent components, i.e., implementing the absMAC layer over a physical network and designing algorithms with the help of the two primitives in the absMAC layer. Thus, it sharply reduces the fussy and complicated process of algorithm design and analysis over the physical network. Our proposed algorithm implements the absMAC layer under the Rayleigh-fading model with no more than a logarithmic factor inferior to the optimal solution in terms of time complexity. The presented simulation results indicate that our algorithm performs well in realistic environments. Furthermore, we show that by making full use of our proposed absMAC layer algorithm, many network primitives such as Neighbor Discovery, Single/Multiple-Message Broadcast, and Consensus, can be efficiently implemented.

Cloud‐assisted Internet of Things (IoT) significantly facilitate IoT devices to outsource their data for high efficient management. Unfortunately, some unsettled security issues dramatically impact the popularity of IoT, such as illegal access and key escrow problem. Traditional public‐key encryption can be used to guarantees data confidentiality, while it cannot achieve efficient data sharing. The attribute‐based encryption (ABE) is the most promising way to ensure data security and to realize one‐to‐many fine‐grained data sharing simultaneously. However, it cannot be well applied in the cloud‐assisted IoT due to the complexity of its decryption and the decryption key leakage problem. To prevent the abuse of decryption rights, we propose a multiauthority ABE scheme with white‐box traceability in this paper. Moreover, our scheme greatly lightens the overhead on devices by outsourcing the most decryption work to the cloud server. Besides, fully hidden policy is implemented to protect the privacy of the access policy. Our scheme is proved to be selectively secure against replayable chosen ciphertext attack (RCCA) under the random oracle model. Some theory analysis and simulation are described in the end.

Age of Information (AoI) is an emerging concept to model information freshness from the perspective of destinations of information deliveries. Serving as a metric to characterize the data delivery timeliness, the peak age indicates the maximum value of the AoI prior to a data packet reception. In this paper, we present a distributed scheduling algorithm for peak age optimization in a wireless network where a number of sensor nodes attempt to deliver their sensed data to a data collector over a wireless channel. In particular, each sensor node accesses the channel for data delivery independently according to an adaptively tuned transmission probability. The beauty of our algorithm lies in that, even with neither centralized infrastructure nor coordinations among the sensor nodes, our algorithm asymptotically approximates the optimal solution by only a constant factor. We perform solid theoretical analysis and extensive simulations to verify the efficacy of our algorithm. To the best of our knowledge, it is the first fully distributed scheduling algorithm for AoI optimization in wireless networks.

Nodes in wireless sensor networks (WSNs) are usually deployed in an unattended even hostile environment. What is worse, these nodes are equipped with limited battery, storage, computation, and communication resources. Therefore, it is challenging to ensure the security of a WSN without decreasing its network performance. Data aggregation (DA) combined with a security mechanism can provide a good scheme for solving the aforementioned problems. This article presents a comprehensive review of secure DA (SDA) in WSNs, including its security goals together with the existing problems. The traditional network topologies as well as new emerging ones are discussed and compared in order to indicate the application scenes and security levels of different topologies. Meanwhile, the contrastive analyses of security strategies are presented which divides SDA protocols into five categories according to different security mechanisms, security goals, and network topologies. Besides, the discussion points out some open issues which may be the valuable topics of SDA in the future.

The Internet of Things (IoT) changed our lives with huge amounts of data production. Due to source-limited IoT devices, one of the best ways to process the data is cloud storage. However, a series of security and privacy issues arise, such as illegal data access, data tampering, and privacy leak. Though symmetric encryption can guarantee data confidentiality, it cannot realize fine-grained data sharing and searching. The keyword-based searchable attribute-based encryption (KSABE) can achieve data confidentiality and fine-grained access control. More importantly, it realizes a keyword-based search for data users. However, the heavy decryption computation burden and the management of massive user keys appear when implementing attribute-based encryption schemes to IoT. Therefore, this article proposes a blockchain-aided searchable attribute-based encryption (BC-SABE) with efficient revocation and decryption, where the traditional centralized server is replaced with a decentralized blockchain system being in charge of the threshold parameter generation, key management, and user revocation. All revocation tasks are done by the blockchain and it is on longer necessary for ciphertext reencryption and key update. Moreover, users utilize the coalition blockchain to generate partial tokens. Besides, the cloud server contained in our scheme not only stores the massive encrypted data but also performs search and predecryption for users who only require one exponentiation in the group G to decrypt fully. Security analyses prove that our scheme realizes the security under the chosen plaintext attack and the chosen keyword attack. Simulations show that the decryption and token generation cost of our scheme are preferable.

One of the best ways to deal with the massive data generated by the Internet of Things (IoT) is storing them in the cloud. However, outsourced storage raises some security and privacy issues, such as data leaking and illegal access. The attribute-based signcryption (ABSC) is one of the most promising approaches which can ensure the confidentiality and authenticity of data simultaneously. Nonetheless, it not only inherits the fine-grained access control but also the heavy computational cost which is intolerable for most resource-limited IoT devices. In this article, we propose lightweight hybrid-policy ABSC (LH-ABSC), a lightweight ABSC scheme which adopts ciphertext-policy encryption (CPABE) and key-policy attribute-based signature (KPABS). Ciphertext-policy attribute-based signature leads the decision making that who can decrypt to the data owners directly. Meanwhile, the signature is related with data owners' attribute set which can be used to testify the authenticity of data. In particular, LH-ABSC has constant signature size and satisfies public verification which is deeply important for IoT devices. Moreover, LH-ABSC outsources most computing overhead to fog nodes, including signature, verify, and decryption. Comprehensive theoretical analyses, such as confidentiality, unforgeability, and verifiability, are provided. Also, the selective chosen ciphertext security, the selective chosen message security, and signers anonymity are achieved.

The rapid growth of DNA-sequencing technologies motivates more personalized and predictive genetic-oriented services, which further attract individuals to increasingly release their genome information to learn about personalized medicines, disease predispositions, genetic compatibilities, etc. Individual genome information is notoriously privacy-sensitive and highly associated with relatives. In this paper, we present an inference attack algorithm to predict target genotypes and phenotypes based on belief propagation in factor graphs. With this algorithm, an attacker can effectively predict the target genotypes and phenotypes of target individuals based on genome information shared by individuals or their relatives, and genotype and phenotype association from genome-wide association study (GWAS). To address the privacy threats resulted from such inference attacks, we elaborate the metrics to evaluate data utility and privacy and then present a data sanitization method. We evaluate our inference attack algorithm and data sanitization method on real GWAS dataset: Age-related macular degeneration (AMD) case/control dataset. The evaluation results show that our work can effectively defense against genome threats while guaranteeing data utility.

Cloud computing has promoted the success of big data applications such as medical data analyses. With the abundant resources provisioned by cloud platforms, the quality of service (QoS) of services that process big data could be boosted significantly. However, due to unstable network or fake advertisement, the QoS published by service providers is not always trusted. Therefore, it becomes a necessity to evaluate the service quality in a trustable way, based on the services' historical QoS records. However, the evaluation efficiency would be low and cannot meet users' quick response requirement, if all the records of a service are recruited for quality evaluation. Moreover, it may lead to `Lagging Effect' or low evaluation accuracy, if all the records are treated equally, as the invocation contexts of different records are not exactly the same. In view of these challenges, a novel approach named Partial Historical Records-based service evaluation approach (Partial-HR) is put forward in this paper. In Partial-HR, each historical QoS record is weighted based on its service invocation context. Afterwards, only partial important records are employed for quality evaluation. Finally, a group of experiments are deployed to validate the feasibility of our proposal, in terms of evaluation accuracy and efficiency.

Resilience problem is defined on a database d, given a boolean query q where q(d) is initially true, and an integer k, it is to find the tuple set d′ of smallest size such that the query result q(d∖d′) becomes false. As a potential explanation of a specified query, resilience plays a fundamental and important role in query explanation, database debugging and error tracing. Complexity results of resilience decision on relational algebraic queries have been studied previously. In this paper, we investigate the resilience decision problem on aggregation queries. New results on the hardness are provided. We show that, this problem is polynomially intractable on nested COUNT and SUM query both under data complexity and parametric complexity, and even it is NP-hard to approximate it within a constant ratio under the active domain constraint.

This article studies the batch processing of truss maintenance in large graphs. Trussness is a widely used index in graph analytics for cohesive subgraph mining. It is defined on edges to reflect the closeness of vertices connected by the edges. The trussness maintenance problem, i.e., updating trussness after edge insertions/deletions and avoiding recomputation, was proposed by Cohen (2008) with the assumption that real graphs are continuously evolving in nature and their dynamicity usually only affects few edges. Different from the existing work that mainly focuses on simple single edge/vertex insertion/deletion, we propose batch processing algorithms for truss maintenance with multiedge insertions/deletions. By presenting an edge structure called triangle disjoint set, whose insertion/deletion can make each edge change its trussness by at most 1, we tackle the difficulty in quantifying the trussness changes of the edges in batch processing. More specifically, we propose two indices, namely sustain support and pivotal support, to help measure whether the edges have the potential to change their trussness, such that the search range of the potential edges is greatly reduced. The extensive experiments on real-world graphs illustrate that compared with the single-edge processing approach, our batch processing algorithms can significantly improve the processing efficiency, and the improvement becomes more obvious when more edges are inserted/deleted.

Enabled by the industrial Internet, intelligent transportation has made remarkable achievements such as autonomous vehicles by carnegie mellon university (CMU) Navlab, Google Cars, Tesla, etc. Autonomous vehicles benefit, in various aspects, from the cooperation of the industrial Internet and cyber-physical systems. In this process, users in autonomous vehicles submit query contents, such as service interests or user locations, to service providers. However, privacy concerns arise since the query contents are exposed when the users are enjoying the services queried. Existing works on privacy preservation of query contents rely on location perturbation or k-anonymity, and they suffer from insufficient protection of privacy or low query utility incurred by processing multiple queries for a single query content. To achieve sufficient privacy preservation and satisfactory query utility for autonomous vehicles querying services in cyber-physical systems, this article proposes a novel privacy notion of client-based personalized k-anonymity (CPkA). To measure the performance of CPkA, we present a privacy metric and a utility metric, based on which, we formulate two problems to achieve the optimal CPkA in term of privacy and utility. An approach, including two modules, to establish mechanisms which achieve the optimal CPkA is presented. The first module is to build in-group mechanisms for achieving the optimal privacy within each content group. The second module includes linear programming-based methods to compute the optimal grouping strategies. The in-group mechanisms and the grouping strategies are combined to establish optimal CPkA mechanisms, which achieve the optimal privacy or the optimal utility. We employ real-life datasets and synthetic prior distributions to evaluate the CPkA mechanisms established by our approach. The evaluation results illustrate the effectiveness and efficiency of the established mechanisms.

This article studies the core maintenance problem for dynamic graphs which requires to update each vertex's core number with the insertion/deletion of vertices/edges. Previous algorithms can either process one edge associated with a vertex in each iteration or can only process one superior edge associated with the vertex (an edge 〈u; v〉 is a superior edge of vertex u if v' core number is no less than u's core number) in each iteration. Thus for high superior-degree vertices (the vertices associated with many superior edges) insertions/deletions, previous algorithms become very inefficient. In this article, we discovered a new structure called joint edge set whose insertions/deletions make each vertex's core number change at most one. The joint edge set mainly contains all the superior edges associated with the high superior-degree vertices as long as these vertices are 3+-hop independent. Based on this discovery, faster parallel algorithms are devised to solve the core maintenance problems. In our algorithms, we can process all edges in the joint edge set in one iteration and thus can greatly increase the parallelism and reduce the processing time. The results of extensive experiments conducted on various types of real-world, temporal, and synthetic graphs illustrate that the proposed algorithms achieve good efficiency, stability and scalability. Specifically, the new algorithms can outperform the single-edge processing algorithms by up to four orders of magnitude. Compared with the matching based algorithm and the superior edge based algorithm, our algorithms show a significant speedup up to 60× in the processing time.

Link scheduling plays a key role in the network capacity and the transmission delay. In this paper, we study the problem of maximum link scheduling (MLS), aiming to characterize the maximum number of links that can be successfully scheduled simultaneously under Rayleigh-fading and multiuser interference. After analyzing the minimum distance between successful links in the existing GHW scheduling algorithm, we propose a DLS (Distance-based Link Scheduling) algorithm. Then, the global interference is characterized and bounded by introducing a separation distance between selected links, building on which we propose a distributed version of DLS (denoted by DDLS) that converges to a constant factor of the non-fading optimum within time complexity$O(n\ln n)$, where$n$is the number of links. Furthermore, we study the Shortest Link Scheduling (SLS) problem, which minimizes the number of time slots to successfully schedule each link for at least once. An algorithm for SLS with approximation factor of$O(\ln n)$is obtained by executing DDLS. Extensive simulations show that DDLS greatly outperforms GHW and the other two popular algorithms.

The development of Internet of Things (IoT) and Mobile Edge Computing (MEC) has led to close cooperation between electronic devices. It requires strong reliability and trustworthiness of the devices involved in the communication. However, current trust mechanisms have the following issues: (1) heavily relying on a trusted third party, which may incur severe security issues if it is corrupted, and (2) malicious evaluations on the involved devices which may bias the trustrank of the devices. By introducing the concepts of risk management and blockchain into the trust mechanism, we here propose a blockchain-based trust mechanism for distributed IoT devices in this paper. In the proposed trust mechanism, trustrank is quantified by normative trust and risk measures, and a new storage structure is designed for the domain administration manager to identify and delete the malicious evaluations of the devices. Evidence shows that the proposed trust mechanism can ensure data sharing and integrity, in addition to its resistance against malicious attacks to the IoT devices.

Wireless Sensor Networks (WSNs) are increasingly involved in many applications. However, communication overhead and energy efficiency of sensor nodes are the major concerns in WSNs. In addition, the broadcast communication mode of WSNs makes the network vulnerable to privacy disclosure when the sensor nodes are subject to malicious behaviours. Based on the abovementioned issues, we present a Queries Privacy Preserving mechanism for Data Aggregation (QPPDA) which may reduce energy consumption by allowing multiple queries to be aggregated into a single packet and preserve data privacy effectively by employing a privacy homomorphic encryption scheme. The performance evaluations obtained from the theoretical analysis and the experimental simulation show that our mechanism can reduce the communication overhead of the network and protect the private data from being compromised.

The extreme boom of online social networks paves the way for rumor propagation, which may incur an economic loss and cause further public panic. Hence, there is a pressing need to develop countermeasures for reducing side effects posed by rumors. Different from the state-of-the-art work that mostly conducted micro-perspective studies, our paper focuses on a macro-perspective one. In detail, our study neglects technical details and analyzes the antagonistic dynamics between the rumormonger and the rumor suppressor, which provides a deep understanding of the overall development trend of rumor propagation. To reveal the potentials of the rumormonger and the rumor suppressor, the competence-oriented analysis is proposed, where the sufficient and necessary conditions for the existence of the Nash equilibrium in this rumor game are proved rigorously, helping us to derive steady ratios of people who trust or deny a rumor. To figure out the optimal strategy to strike back the rumormonger, the target-oriented analysis is conducted, in which the analytical solutions when the strategies of both players are static are solved and an iteration algorithm is employed to obtain the numerical solutions when their strategies are dynamic. Both numerical and real-world-data based simulations are adopted to verify the proposed competence-oriented and target-oriented analyses.

We study the fundamental problem of fault-tolerant distributed sampling towards uniform probabilistic distribution in dynamic multi-hop wireless networks. Whereas uniform sampling has been extensively studied without concerning fault tolerance, only quite few proposals investigate how the uniform sampling algorithm tolerate Byzantine faults on dynamic networks with very special topologies, e.g., regular graphs with constant node degree. Therefore, designing fault-tolerant uniform sampling algorithms for more general graphs is still an open problem. To this end, we propose a fast and highly fault-tolerate randomized algorithm, such that nearly-uniform sampling is achieved in O(log2n) rounds, while up to O(√n/(polylog(n)·Δ)) Byzantine nodes can be tolerated, where Δ is the maximum degree of the network. Moreover, the proposed algorithm is also communication efficient in the sense that only O(log n) bits need to be exchanged on each link in every round. To show the power of distributed uniform sampling, we apply the proposed algorithm in designing polylogarithmic time distributed algorithms for two typical fundamental issues, i.e., to achieve agreement or data aggregation in Byzantine dynamic networks.

This paper studies jamming-resilient distributed backbone construction in multi-hop wireless networks. Specifically, a strong adversarial jamming model is proposed that captures the general jamming phenomena suffered by wireless communications. The jamming model is based on the realistic Signal-to-Interference-plus-Noise-Ratio (SINR) interference model, and is featured by local-uniformity, unrestricted energy budget and reactivity, which covers more jamming scenarios and is much closer to reality than existing jamming models. Under the strong adversarial jamming model, we propose a randomized distributed algorithm that can construct a backbone in J(O(log n + logR)) rounds with high probability, where J(O(log n + log R)) is the number of rounds in the interval from the beginning of the algorithm execution that contains O(log n + log R) unjammed rounds for every node. This result is asymptotically optimal considering the trivial lower bound of Ω(log n) for a successful transmission even without interference and jamming.

This paper investigates distributed Dominating Set (DS) and Connected Dominating Set (CDS) construction in dynamic wireless networks under the SINR interference model. Specifically, we present a new model for dynamic networks that admits both churns (due to node arrivals/departures) and node mobility. Under this dynamic model, we propose efficient algorithms to construct a DS and a CDS with constant approximation ratios w.r.t. the corresponding minimum ones in O(log n) time with a high probability guarantee. To the best of our knowledge, these algorithms are the first known ones for DS and CDS construction in dynamic networks assuming the SINR interference model. We believe our dynamic network model can greatly facilitate distributed algorithm studies in mobile and dynamic wireless networks.

In smart grid systems, vulnerable lines may lead to cascading failures which can cause large-scale blackouts. Successfully detecting vulnerable lines can increase the stability of the smart grid systems and reduce the risk of cascading failures. By modeling a smart grid system into a directed graph, we investigate the problem of vulnerable line identification from a clustering perspective. By jointly considering the topological parameters and the electrical properties, we propose an affinity propagation-based bus clustering algorithm to classify buses into clusters, where the center of each cluster represents the most influential bus in each partition. According to the clustering results, we design a vulnerable line identification scheme, which captures different types of potential critical lines in the smart grid system. Experiments over the IEEE-39 bus system demonstrate the effectiveness and correctness of our proposed algorithm.

We define the following problem termed n × 1-out-of-n oblivious transfer (n × 1-out-of-n OT): in a system with one server and n clients, how to securely and efficiently assign n secrets to n clients by the server, with each client getting a unique secret from the server, and the server and clients remain unknown of how the secrets are distributed? This is a novel problem that is fundamentally different than 1-out-of-n OT repeated n times, and is different than k-out-of-n OT as well. Nevertheless, the proposed OT has many practical applications such as privacy-preserving data aggregation in smart grids. It can also be employed to design crypto protocols for anonymous communications and group signatures. In this paper, we propose the first algorithm to efficiently and effectively implement the n × 1-out-of-n OT. We construct hidden permutation circuits to obliviously assign n secrets to n clients by the server within O(lg(n)) time. A rigorous theoretical analysis is also carried out to investigate the security strength and performance of the protocol.

Health-related Internet of Things (IoT) devices are becoming more popular in recent years. On the one hand, users can access information of their health conditions more conveniently; on the other hand, they are exposed to new security risks. In this paper, we presented, to the best of our knowledge, the first in-depth security analysis on home-use electroencephalography (EEG) IoT devices. Our key contributions are twofold. First, we reverse-engineered the home-use EEG system framework via which we identified the design and implementation flaws. By exploiting these flaws, we developed two sets of novel easy-to-exploit PoC attacks, which consist of four remote attacks and one proximate attack. In a remote attack, an attacker can steal a user's brain wave data through a carefully crafted program while in the proximate attack, the attacker can steal a victim's brain wave data over-the-air without accessing the victim's device on any sense when he is close to the victim. As a result, all the 156 brain-computer interface (BCI) apps in the NeuroSky App store are vulnerable to the proximate attack. We also discovered that all the 31 free apps in the NeuroSky App store are vulnerable to at least one remote attack. Second, we proposed a novel deep learning model of a joint recurrent convolutional neural network (RCNN) to infer a user's activities based on the reduced-featured EEG data stolen from the home-use EEG IoT devices, and our evaluation over the real-world EEG data indicates that the inference accuracy of the proposed RCNN is can reach 70.55%.

The rapid developments of the Internet of Things (IoT) and smart mobile devices in recent years have been dramatically incentivizing the advancement of edge computing. On the one hand, edge computing has provided a great assistance for lightweight devices to accomplish complicated tasks in an efficient way; on the other hand, its hasty development leads to the neglection of security threats to a large extent in edge computing platforms and their enabled applications. In this paper, we provide a comprehensive survey on the most influential and basic attacks as well as the corresponding defense mechanisms that have edge computing specific characteristics and can be practically applied to real-world edge computing systems. More specifically, we focus on the following four types of attacks that account for 82% of the edge computing attacks recently reported by Statista: distributed denial of service attacks, side-channel attacks, malware injection attacks, and authentication and authorization attacks. We also analyze the root causes of these attacks, present the status quo and grand challenges in edge computing security, and propose future research directions.

Due to the prominent development of public transportation systems, the taxi flows could nowadays work as a reasonable reference to the trend of urban population. Being aware of this knowledge will significantly benefit regular individuals, city planners, and the taxi companies themselves. However, to mindlessly publish such contents will severely threaten the private information of taxi companies. Both their own market ratios and the sensitive information of passengers and drivers will be revealed. Consequently, we propose in this paper a novel framework for privacy-preserved traffic sharing among taxi companies, which jointly considers the privacy, profits, and fairness for participants. The framework allows companies to share scales of their taxi flows, and common knowledge will be derived from these statistics. Two algorithms are proposed for the derivation of sharing schemes in different scenarios, depending on whether the common knowledge can be accessed by third parties like individuals and governments. The differential privacy is utilized in both cases to preserve the sensitive information for taxi companies. Finally, both algorithms are validated on real-world data traces under multiple market distributions.

It has been found that there exists an essential similarity between solving equations and controlling dynamic systems: Both errors are expected to decrease to zero (or an acceptably tiny value) as soon as possible. By exploiting such a similarity, researchers have presented and investigated continuous-time recurrent neural network models for solving time-varying problems. To be compatible with digital computers, it is desirable to develop discrete-time neural algorithms from the control perspective for performance improvement. In this paper, a discrete-time zeroing neural algorithm is proposed for the solving system of linear equations with the aid of control techniques. To lay a basis for theoretical analyses, the proposed zeroing neural algorithm with nonlinearity is converted into a second-order linear system plus a residual term, and then, analyzed using the control theory. Theoretical results and numerical experiments are provided, which illustrate that the proposed neural algorithm possesses an improved performance compared to the existing solutions.

As the next generation of information and communication infrastructure, Internet of Things (IoT) enables many advanced applications such as smart healthcare, smart grid, smart home, and so on, which provide the most flexibility and convenience in our daily life. However, pervasive security and privacy issues are also increasing in IoT. For instance, an attacker can get health condition of a patient via analyzing real-time records in a smart healthcare application. Therefore, it is very important for users to protect their private data. In this paper, we present two efficient data aggregation schemes to preserve private data of customers. In the first scheme, each IoT device slices its actual data randomly, keeps one piece to itself, and sends the remaining pieces to other devices which are in the same group via symmetric encryption. Then, each IoT device adds the received pieces and the held piece together to get an immediate result, which is sent to the aggregator after the computation. Moreover, homomorphic encryption and AES encryption are employed to guarantee secure communication. In the second scheme, the slicing strategy is also employed. Noise data are introduced to prevent the exchanged actual data of devices from disclosure when the devices blend data each other. AES encryption is also employed to guarantee secure communication between devices and aggregator, compared to homomorphic encryption, which has significantly less computational cost. Analysis shows that integrity and confidentiality of IoT devices’ data can be guaranteed in our schemes. Both schemes can resist external attack, internal attack, colluding attack, and so on.

Smart home IoT devices have been more prevalent than ever before but the relevant security considerations fail to keep up with due to device and technology heterogeneity and resource constraints, making IoT systems susceptible to various attacks. In this paper, we propose a novel graph-based mechanism to identify the vulnerabilities in communication of IoT devices for smart home systems. Our approach takes one or more packet capture files as inputs to construct a traffic graph by passing the captured messages, identify the correlated subgraphs by examining the attribute-value pairs associated with each message, and then quantify their vulnerabilities based on the sensitivity levels of different keywords. To test the effectiveness of our approach, we setup a smart home system that can control a smart bulb LB100 via either the smartphone APP for LB100 or the Google Home speaker. We collected and analyzed 58,714 messages and exploited 6 vulnerable correlated sub graphs, based on which we implemented 6 attack cases that can be easily reproduced by attackers with little knowledge of IoT. This study is novel as our approach takes only the collected traffic files as inputs without requiring the knowledge of the device firmware while being able to identify new vulnerabilities. With this approach, we won the third prize out of 20 teams in a hacking competition.

In this paper, we present the first algorithm for exactly implementing the abstract MAC (absMAC) layer in the physical SINR model. The absMac layer, first presented by Kuhn et al. in [15], provides reliable local broadcast communication, with timing guarantees stated in terms of a collection of abstract delay functions, such that high-level algorithms can be designed in terms of these functions, independent of specific channel behavior. The implementation of absMAC layer is to design a distributed algorithm for the local broadcast communication primitives over a particular communication model that defines concrete channel behaviors, and the objective is minimizing the bounds of the abstract delay functions. Halldórsson et al. [10] have shown that in the standard SINR model (synchronous communication, without physical carrier sensing or location information), there cannot be efficient exact implementations. In this work, we show that physical carrier sensing, a commonly seen function performed by wireless devices, can help get efficient exact implementation algorithms. Specifically, we propose an algorithm that exactly implements the absMAC layer. The algorithm provides asymptotically optimal bounds for both acknowledgement and progress functions defined in the absMAC layer. Our algorithm can lead to many new faster algorithms for solving high-level problems in the SINR model. We demonstrate this by giving algorithms for problems of Consensus, Multi-Message Broadcast and Single-Message Broadcast. It deserves to point out that our implementation algorithm is designed based on an optimal algorithm for a General Local Broadcast (GLB) problem, which takes the number of distinct messages into consideration for the first time. The GLB algorithm can handle much more communication scenarios apart from those defined in the absMAC layer. Simulation results show that our proposed algorithms perform well in reality.

Dynamicity is one of the critical characteristics and a major challenge in designing communication protocols in wireless networks. Most of the previous works had focused on the internal node changes (e.g., mobility, arrival, or departure) and not considered the effect of external environmental change. However, the external environmental change, in general, is a more complex phenomenon that can impede nodes from successful communication, implying the protocols of the previous dynamic models do not work well in practice. In this paper, we give an algorithm for distributed broadcasting in a more general model with fully dynamic wireless networks, called FD-Broadcast. Specifically, we present a fully dynamic model which allows node mobility and churns (due to node arrivals/departure) and external environmental change. In contrast to the previous works on dynamic networks, our model defines the full dynamicity in terms of localized topological changes of each node and can tolerate some external environmental change. The external environment changes are captured by the random jamming method. We show that FD-Broadcast can achieve broadcasting in$O(D_{S})$rounds with a high probability guarantee under the assumption of constant dynamic rate in the SINR model, where$D_{S}$is the dynamic diameter, a parameter proposed to depict the complexity of dynamic broadcasting. Moreover, the lower bound of dynamic broadcasting is proved to be$\Omega(D_{S})$, thus, FD-Broadcast is asymptotically optimal with high probability.

Applying the proliferated location-based services (LBSs) to social networks has spawned mobile social network (MSN) services that allow users to discover potential friends around them. While enjoying the convenience of MSN services, the mobile users also are confronted with the risk of location disclosure, which is a severe privacy preserving concern. In this paper, we focus on the problem of location privacy preserving in MSN. Particularly, we propose a repartitioning anonymous region for location privacy preserving (RPAR) scheme based on the central anonymous location which minimizes the traffic between the anonymous server and the LBS server while protecting the privacy of the user location. Furthermore, our scheme enables the users to get more accurate query results, thus improving the quality of the location service. Simulation results show that our proposed scheme can effectively reduce the area of anonymous regions and minimize the traffic.

Due to the complexity and volume, outsourcing ciphertexts to a cloud is deemed to be one of the most effective approaches for big data storage and access. Nevertheless, verifying the access legitimacy of a user and securely updating a ciphertext in the cloud based on a new access policy designated by the data owner are two critical challenges to make cloud-based big data storage practical and effective. Traditional approaches either completely ignore the issue of access policy update or delegate the update to a third party authority; but in practice, access policy update is important for enhancing security and dealing with the dynamism caused by user join and leave activities. In this paper, we propose a secure and verifiable access control scheme based on the NTRU cryptosystem for big data storage in clouds. We first propose a new NTRU decryption algorithm to overcome the decryption failures of the original NTRU, and then detail our scheme and analyze its correctness, security strengths, and computational efficiency. Our scheme allows the cloud server to efficiently update the ciphertext when a new access policy is specified by the data owner, who is also able to validate the update to counter against cheating behaviors of the cloud. It also enables (i) the data owner and eligible users to effectively verify the legitimacy of a user for accessing the data, and (ii) a user to validate the information provided by other users for correct plaintext recovery. Rigorous analysis indicates that our scheme can prevent eligible users from cheating and resist various attacks such as the collusion attack.

Recommending appropriate product items to the target user is becoming the key to ensure continuous success of E-commerce. Today, many E-commerce systems adopt various recommendation techniques, e.g., Collaborative Filtering (abbreviated as CF)-based technique, to realize product item recommendation. Overall, the present CF recommendation can perform very well, if the target user owns similar friends (user-based CF), or the product items purchased and preferred by target user own one or more similar product items (item-based CF). While due to the sparsity of big rating data in E-commerce, similar friends and similar product items may be both absent from the user-product purchase network, which lead to a big challenge to recommend appropriate product items to the target user. Considering the challenge, we put forward a Structural Balance Theory-based Recommendation (i.e., SBT-Rec) approach. In the concrete, (I) user-based recommendation: we look for target user's “enemy” (i.e., the users having opposite preference with target user); afterwards, we determine target user's “possible friends”, according to “enemy's enemy is a friend” rule of Structural Balance Theory, and recommend the product items preferred by “possible friends” of target user to the target user. (II) likewise, for the product items purchased and preferred by target user, we determine their “possibly similar product items” based on Structural Balance Theory and recommend them to the target user. At last, the feasibility of SBT-Rec is validated, through a set of experiments deployed on MovieLens-1M dataset.

Non-negative Matrix Factorization (NMF), a classical method for dimensionality reduction, has been applied in many fields. It is based on the idea that negative numbers are physically meaningless in various data-processing tasks. Apart from its contribution to conventional data analysis, the recent overwhelming interest in NMF is due to its newly discovered ability to solve challenging data mining and machine learning problems, especially in relation to gene expression data. This survey paper mainly focuses on research examining the application of NMF to identify differentially expressed genes and to cluster samples, and the main NMF models, properties, principles, and algorithms with its various generalizations, extensions, and modifications are summarized. The experimental results demonstrate the performance of the various NMF algorithms in identifying differentially expressed genes and clustering samples.

Crowdsourcing applications are vulnerable to malicious behaviors, posing serious threats to their adoption and large deployment. Based on the notion that the requestor (i.e., the crowdsourcer) can block malicious behaviors via leveraging the market power through task allocation and pricing, we propose two novel frameworks based on the mechanism design game theory (i.e., the reverse game theory). To the best of our knowledge, we are the first to exploit the market power and to apply the mechanism design game theory in thwarting malicious behaviors in crowdsourcing. The first proposed framework is built on a requestor-dominant mechanism design game (Rd-MDG), where the game rule is determined solely by the requestor. The second proposed framework is based on the worker-assisted mechanism design game (WaMDG), where the worker (i.e., the contributor) can assist the requestor to determine the game rules by offering advices. These two frameworks have the following salient features: i) neither of them requires the workers to reveal their private information; ii) the game rules of each framework are designed to be able to force the workers to calculate their best strategies based on their actual private information; iii) our theoretical analysis shows that equilibriums exist for both frameworks; and iv) our extensive simulation results demonstrate that these two frameworks can thwart malicious behaviors by driving the workers with a higher attack intent into obtaining lower utilities.

As a virtual backbone structure, connected dominating sets (CDSs) play an important role in topology control for wireless networks. In this paper, we develop a distributed self-stabilizing CDS construction algorithm under the SINR model (also known as the physical interference model), a more practical yet more challenging interference model for distributed algorithm design. Specifically, we propose a randomized distributed algorithm that can construct a CDS in O (log n) timeslots with a high probability, where n is the total number of nodes in the network. The constructed CDS achieves constant approximation in both density and diameter. To the best of our knowledge, this is the first known asymptotically optimal self-stabilizing result in terms of both density and diameter for distributed CDS construction under the practical SINR model.

This paper analyzes the secrecy transmission capacity (STC) over wireless ad hoc networks, where the legitimate nodes and eavesdroppers are distributed as Poisson point process. We calculate the connection outage probability (COP) and the bounds of the secrecy outage probability (SOP) based on the tools from stochastic geometry and establish a theoretical model for STC. Different from previous work considering the lower bound of STC, we characterize the relationship between target outage constraints and the densities of legitimate transmitters and eavesdroppers, and propose a necessary condition to achieve an upper bound of the positive STC. That is, the length of legitimate transmitter-receiver pair has an upper bound.

Today, there is widespread use of mobile applications that take advantage of a user's location. Popular usages of location information include geotagging on social media websites, driver assistance and navigation, and querying nearby locations of interest. However, the average user may not realize the high energy costs of using location services (namely the GPS) or may not make smart decisions regarding when to enable or disable location services-for example, when indoors. As a result, a mechanism that can make these decisions on the user's behalf can significantly improve a smartphone's battery life. In this paper, we present an energy consumption analysis of the localization methods available on modern Android smartphones and propose the addition of an indoor localization mechanism that can be triggered depending on whether a user is detected to be indoors or outdoors. Based on our energy analysis and implementation of our proposed system, we provide experimental results-monitoring battery life over time-and show that an indoor localization method triggered by indoor or outdoor context can improve smartphone battery life and, potentially, location accuracy.

The Internet of Things (IoT) is changing human lives by connecting everyday objects together. For example, in a grocery store, all items can be connected with each other, forming a smart shopping system. In such an IoT system, an inexpensive radio frequency identification (RFID) tag can be attached to each product which, when placed into a smart shopping cart, can be automatically read by a cart equipped with an RFID reader. As a result, billing can be conducted from the shopping cart itself, preventing customers from waiting in a long queue at checkout. Additionally, smart shelving can be added into this system, equipped with RFID readers, and can monitor stock, perhaps also updating a central server. Another benefit of this kind of system is that inventory management becomes much easier, as all items can be automatically read by an RFID reader instead of manually scanned by a laborer. To validate the feasibility of such a system, in this paper we identify the design requirements of a smart shopping system, build a prototype system to test functionality, and design a secure communication protocol to make the system practical. To the best of our knowledge, this is the first time a smart shopping system is proposed with security under consideration.

Ultraviolet (UV) radiation has a great impact on human health. Nowadays, the public basically gets information about UV radiation through weather forecasts, which can only provide rough and average prediction for a certain large area. Since CMOS sensors in smartphone cameras are very sensitive to UV radiation, smartphones have potential to be the ideal equipment to measure it. At the same time, result optimization can be achieved in real time by taking advantage of fog computing because fog servers are able to aggregate UV radiation data and compute the results at local areas. This paper exhaustively discussed a novel procedure that could measure UV radiation through smartphone cameras, and also briefly covered how to leverage fog computing to improve UV measurement accuracy. To implement the procedure, an Android app called UV meter was developed. Experiments were conducted by utilizing the app to validate and evaluate the correctness and accuracy of the procedure on both smartphones and smart watches. Results showed that the proposed procedure could achieve an average of 95% accuracy of a typical professional digital UV meter, and could be easily implemented on smart devices.

The development of the Internet of Things has made extraordinary progress in recent years in both academic and industrial fields. There are quite a few smart home systems (SHSs) that have been developed by major companies to achieve home automation. However, the nature of smart homes inevitably raises security and privacy concerns. In this paper, we propose an improved energy-efficient, secure, and privacy-preserving communication protocol for the SHSs. In our proposed scheme, data transmissions within the SHS are secured by a symmetric encryption scheme with secret keys being generated by chaotic systems. Meanwhile, we incorporate message authentication codes to our scheme to guarantee data integrity and authenticity. We also provide detailed security analysis and performance evaluation in comparison with our previous work in terms of computational complexity, memory cost, and communication overhead.

Due to the close correlation with individual's physical features and status, the adoption of cyber-physical social systems (CPSSs) has been inevitably hindered by users' privacy concerns. Such concerns keep growing as our bile devices have more embedded sensors, while the existing countermeasures only provide incapable and limited privacy preservation for sensitive physical information. Therefore, we propose a novel privacy preservation framework for CPSSs. We formulate both the privacy concerns and user expectations in CPSSs based on real-world knowledge. We also design a corresponding data publishing mechanism for users. It regulates the publishing behaviors to hide sensitive physical profiles. Meanwhile, the published data retain comprehensive social profiles for users. Our analysis demonstrates that the mechanism achieves a local maximized performance on the aspect published data size. The experiment results toward real datasets reveals that the performance is comparable to the global optimal one.

More and more Web services raise the demands of personalized service recommendation; there exist some recommendation technologies, which improve the qualities of service recommendation by using service ranking and collaborative filtering. However, privacy and security are also important issues in service scheduling process; social relationships have been the key factors of interpersonal communication; service selection based on user preferences has become an inevitable trend. Starting from user demand preferences, this paper analyzes social topology and service demand information and obtains trusted social relationships; then we construct the fusion model of service historical preferences and potential ones; according to social service recommendation demands, TSRSR algorithm has completed designing. Through experiments, TSRSR algorithm is much better than the others, which can effectively improve potential preferences’ learning. Furthermore, the research results of this paper have more significance to study the security and privacy of service recommendation.

In this paper, we consider the problem of mutual privacy protection in social participatory sensing in which individuals contribute their private information to build a (virtual) community. Particularly, we propose a mutual privacy preserving k-means clustering scheme that neither discloses an individual's private information nor leaks the community's characteristic data (clusters). Our scheme contains two privacy-preserving algorithms called at each iteration of the k-means clustering. The first one is employed by each participant to find the nearest cluster while the cluster centers are kept secret to the participants; and the second one computes the cluster centers without leaking any cluster center information to the participants while preventing each participant from figuring out other members in the same cluster. An extensive performance analysis is carried out to show that our approach is effective for k-means clustering, can resist collusion attacks, and can provide mutual privacy protection even when the data analyst colludes with all except one participant.

This paper presents the first distributed algorithm to construct a spanner for arbitrary ad hoc networks under the physical signal-to-interference-and-noise-ratio (SINR) interference model. Spanner construction is one of the most important techniques for topology control in wireless networks, which intends to find a sparse topology in which only a small number of links need to be maintained, without substantially degrading the path connecting any pair of the nodes in the network. Due to the non-local property of interference, constructing a spanner is challenging under the SINR model, especially when a local distributed algorithm is desired. We meet this challenge by proposing an efficient randomized distributed algorithm that can construct a spanner in O(log n log Γ) timeslots with a high probability, where n is the total number of nodes and Γ describes the ratio of the maximum distance to the minimum distance between nodes. The constructed spanner concurrently satisfies two most desirable properties: constant stretch and linear sparseness. Our algorithm employs a novel maximal independent set (MIS) procedure as a subroutine, which is crucial in achieving the time efficiency of spanner construction. The MIS algorithm improves the best known result of O(log2n) [33] to O(log n) and is of independent interest as the algorithm is applicable also to many other applications. We conduct simulations to verify the proposed spanner construction algorithm, and the results show that our algorithm also performs well in realistic environments.

Spanner construction is one of the most important techniques for topology control in wireless networks. A spanner can help not only to decrease the number of links and to maintain connectivity but also to ensure that the distance between any pair of communication nodes is within some constant factor from the shortest possible distance. Due to the non-locality, constructing a spanner is especially challenging under the physical interference model signal-to-interference-and-noise-ratio (SINR). In this paper, we develop two localized randomized algorithms SINR-directed-YG and SINR-undirected-YG to construct a directed Yao graph (YG) and an undirected YG in O(log n) (n is the number of wireless nodes) time slots with a high probability, in which each node is capable of performing successful local broadcasts to gather neighborhood information within a certain region and the SINR constraint is satisfied at all the steps of the algorithms. The resultant graph of SINR-undirected-YG, which is based on SINR-directed-YG, possesses a constant stretch factor 1/1-2 sin(π/c), where c > 6 is a constant. To the best of our knowledge, SINR-undirected-YG is the first spanner construction algorithm under SINR. We also obtain Yao-Yao graph under SINR. Extensive theoretical performance analysis and simulation study are carried out to verify the effectiveness and the efficiency of our proposed algorithms.

Holistic aggregations are popular queries for users to obtain detailed summary information from Wireless Sensor Networks. An aggregation operation is holistic if there is no constant bound on the size of the storage needed to describe a sub-aggregation. Since holistic aggregation cannot be distributable, it requires that all the sensory data should be sent to the sink in order to obtain the exact holistic aggregation results, which costs lots of energy. However, in most applications, exact holistic aggregation results are not necessary; instead, approximate results are acceptable. To save energy as much as possible, we study the approximated holistic aggregation algorithms based on uniform sampling. In this article, four holistic aggregation operations, frequency, distinct-count, rank, and quantile, are investigated. The mathematical methods to construct their estimators and determine optional sample size are proposed, and the correctness of these methods are proved. Four corresponding distributed holistic algorithms to derive (ϵ, δ)-approximate aggregation results are given. The solid theoretical analysis and extensive simulation results show that all the proposed algorithms have high performance on the aspects of accuracy and energy consumption.

Recent research shows that characteristic gene selection based on gene expression data remains faced with considerable challenges. This is primarily because vast amount of gene expression data have been generated with the development of gene detection technology. Nonetheless, the recognition rate and reliability of gene selection still need to be improved. In this paper, we propose a novel constrained method: robust graph regularized discriminative nonnegative matrix factorization (RGDNMF) for characteristic gene selection. The method mainly includes two aspects: firstly, we incorporate both intrinsic geometrical structure and discriminative label information into the NMF model. Secondly, we adopt L2,1 -norm minimization to both the error function and the regularization term which is robust to noises and outliers in gene data. Furthermore we present the multiplicative update rules and the convergence proof. Our experiments demonstrate that RGDNMF is far more effective than other existing methods.

Sparse Principal Component Analysis (SPCA) is a method that can get the sparse loadings of the principal components (PCs), and it may formulate PCA as a regression-type optimization problem by using the elastic net. But the selected features are different with each PC and generally independent. A new method named SPCA has been proposed for removing these detect, which replaces the elastic net with L2,1-norm penalty. The results of the method on gene expression data are still unknown. Therefore, we will take a test to prove this point in this paper. Firstly, this method is applied to the simulated data for obtaining an optimal parameter. Secondly, the L2,1SPCA method is applied to the gene expression data, that is the head and neck squamous carcinoma data (HNSC). Thirdly, the characteristic genes are selected according the PCs. The results consist of very lower P-value and very higher hit count, which shows the method of L2,1SPCA can obtain higher recognition accuracy and higher relevancy to the genes. Finally, the experimental results demonstrate that the L2,1SPCA works well and has good performances in the gene expression data.

Video surveillance has been widely adopted to ensure home security in recent years. Most video encoding standards such as H.264 and MPEG-4 compress the temporal redundancy in a video stream using difference coding, which only encodes the residual image between a frame and its reference frame. Difference coding can efficiently compress a video stream, but it causes side-channel information leakage even though the video stream is encrypted, as reported in this paper. Particularly, we observe that the traffic patterns of an encrypted video stream are different when a user conducts different basic activities of daily living, which must be kept private from third parties as obliged by HIPAA regulations. We also observe that by exploiting this side-channel information leakage, attackers can readily infer a user's basic activities of daily living based on only the traffic size data of an encrypted video stream. We validate such an attack using two off-the-shelf cameras, and the results indicate that the user's basic activities of daily living can be recognized with a high accuracy.

The use of mobile phones while driving has become a major source of distraction to drivers, leading to a large number of car accidents. In this paper, we study the problem of automatically detecting driver phone calls by monitoring smartphone activities and utilizing the vehicle on-board unit. The challenges to overcome include: i) passenger phone calls should be allowed while the calls of the driver should be blocked; ii) the detection mechanism should be phone position-independent and phone owner-independent as the driver may put the smartphone at any position in the front row and make calls via an earphone, or the driver may borrow a passenger's phone to make a call; iii) the in-vehicle environment is noisy resulted from the operating engine, the music the driver and passenger may listen to, and the conversation between passengers and/or the driver; and iv) the computational cost at the smartphone should be light as realtime phone call detection is expected to effectively block an ongoing call to and from the driver. To overcome these challenges and achieve our objective of detecting driver phone calls, we take advantage of the uniqueness of individual's voice features. Through a short period of learning stage, our proposed system can recognize the driver's voice from the collected audio data. Combined with the smartphone's call state, our scheme can determine whether the driver is participating in the current phone call or not. Our strategy takes into account the complicated in-vehicle environment, and the proposed algorithm does not rely on the location of the phone within the vehicle nor the ownership of the smartphone, as the most existing driver phone call detection mechanisms do. We develop a client-server based system with the smartphones being the clients and the vehicle on-board unit being the server. To validate our mechanism, we perform extensive real-world experiments under different scenarios. The results demonstrate a high probability of detecting driver phone calls with a small false alarm rate.

Global broadcasting is a fundamental problem in wireless multi-hop networks. In this paper, we propose two distributed deterministic algorithms for global broadcasting based on the Signal-to-Interference-plus-Noise-Ratio (SINR) model. In both algorithms, an arbitrary node can become the source node, and the rest of the nodes are divided into different layers according to their distance to the source node. A broadcast message is propagated from the source node to all the other nodes in a layer by layer fashion. Our first proposed algorithm (named TEGB) selects a Maximal Independent Set (MIS) for each layer. Subsequently, multiple subsets of the MIS are carefully selected so as to allow the most concurrent transmissions. Our theoretical analysis shows that TEGB has the time complexity of O(D log n), where n is the total number of nodes in the network and D is the diameter of the network. Compared with the popular algorithm DetGenBroadcast proposed in the work of Jurdzinski et al.(2013), TEGB has a logarithmic improvement in running time. Furthermore, we develop the second algorithm (named TBGB) to reduce the number of duplicated broadcast messages at each layer. To be specific, TBGB attempts to form a unidirectional spanning tree of the network. On the spanning tree, only the non-leaf nodes transmit the broadcast message. Therefore, the redundant broadcasts in the same layer are eliminated. Our theoretical analysis shows that TBGB has the time complexity of O(DΔ log n), where Δ is the maximum node degree.

As a distributed system, a wireless network, usually faces a complex environment (transient faults and topology changes occur frequently). The connected dominating set (CDS) problem has been widely studied due to its important applications in wireless communication and networks, especially the important role as a virtual backbone for efficient routing. In this paper, under SINR (Signal-to-Interference-plus-Noise-Ratio) model, we propose a distributed self-stabilizing maximal independent set (MIS) algorithm (DSSMIS). Based on DSSMIS, we design a distributed self-stabilizing algorithm (DSSCDS) for CDS construction with constant approximation within O(log n) rounds. To best of our knowledge, this is the first self-stabilizing CDS algorithm under SINR model.

Discrete beeping is an extremely rigorous local broadcast model depending only on carrier sensing. It describes an anonymous broadcast network where the nodes do not need unique identifiers and have no knowledge about the topology and size of the network. Within such a model, time is divided into slots, and nodes can either beep or keep silent at each slot. We consider the problem of constructing a minimum dominating set (MDS) and a minimum connected dominating set (MCDS), respectively, under the discrete beeping model in this paper. By assuming that an upper bound N of the network size is known, we first propose and analyze a distributed synchronous algorithm termed BMDS for constructing a minimum dominating set (MDS) and then propose a distributed synchronous algorithm BCDS for CDS construction based on a maximal independent set (MIS) algorithm and a weakly CDS (WCDS). To our best knowledge, we are the first to study the MCDS construction under the discrete beeping model. We prove that the time complexity of BMDS is O(log2N) rounds with constant approximation ratio of at most 2, and BCDS can converge to a CDS within O(log3N) rounds.

This paper initiates the study of distributed information exchange in multi-channel wireless ad hoc networks. Information exchange is a basic operation in which each node of the network sends an information packet to other nodes within a specific distance R. Our study is motivated by the increasing presence and popularity of wireless networks and devices that operate on multiple channels. Consequently, there is a need for a better understanding of how and by how much multiple channels can improve communication. Based on the SINR interference model, we propose a multi-channel network model which incorporates certain features commonly seen in wireless ad hoc networks, including asynchrony, little non-local knowledge, limited message size, and limited power control. We then present a randomized algorithm that can accomplish information exchange in O ((Δ/F + Δlog n/P) log n + log Δ log n) timeslots with high probability, where n is the number of nodes in the network, Δ is the maximum number of nodes within the range R, F is the number of available channels and P is the maximum number of packets that can fit in a message. Our algorithm significantly surpasses the best known results in single-channel networks, achieving a Θ(F) times speedup if Δ and P are sufficiently large. We conducted empirical studies that confirmed the performance of the proposed algorithm as derived in the analysis.

In communication networks such as social networks, wireless networks and biology networks, it is of importance to find all cliques which can help understand the network topology. The clique structures can also be utilized in facilitating message forwarding in wireless networks. For instance, using a set of cliques of maximal and disjoint, one of the nodes in each clique can be elected to forward messages, by which the duplicate message transmissions can be efficiently reduced. Further, it is well known that the maximum clique problem (MCP) is closely related to the maximum independent set and the vertex cover problems. In recent years, the fundamental problem of finding maximal cliques or maximum cliques has attracted lots of attentions. However, few of these works focus on distributed solutions in wireless networks. In this paper, we pay our attention to this missing corner of research. Specifically, we first give a distributed algorithm which can compute all maximal cliques in a wireless network represented by a graph. The algorithm takes O(n) time and uses O(mn) messages, where n is the number of nodes and m the number of edges. Then, with the proposed algorithms MCP (maximum clique problem) and UMCP (unique MCP), we show that a unique maximum clique can be selected from all maximal cliques in O(n) rounds and using O(mn) messages. To the best of our knowledge, our algorithms are the first deterministic distributed solutions for MCP in wireless networks.

Multiple-message broadcast is a generalization of the traditional broadcast problem. It is to disseminate k distinct (1 ≤ k ≤ n) messages stored at k arbitrary nodes to the entire network with the fewest timeslots. In this paper, we study this basic communication primitive in unstructured wireless networks under the physical interference model (also known as the SINR model). The unstructured wireless network assumes unknown network topology, no collision detection and asynchronous communications. Our proposed randomized distributed algorithm can accomplish multiple-message broadcast in O((D + k) log n + log2n) timeslots with high probability, where D is the network diameter and n is the number of nodes in the network. To our best knowledge, this work is the first one to consider distributively implementing multiple-message broadcasting in unstructured wireless networks under a global interference model, which may shed some light on how to efficiently solve in general a “global” problem in a “local” fashion with “global” interference constraints in asynchronous wireless ad hoc networks. Apart from the algorithm, we also show an Ω(D+k+log n) lower bound for randomized distributed multiple message broadcast algorithms under the assumed network model.

Efficient routing protocol will receive a prolonged network lifetime. In this paper we propose an energy-efficient multi-hop routing protocol for wireless sensor networks (EEMR). It mainly includes nodes clustering and inter- cluster multi-hop routing selection. In clustering stage, we introduce an uneven clustering mechanism. Cluster heads which are closer to the base station (BS) have smaller cluster size than those farther from BS, thus they can preserve some energy for the purpose of inter-cluster data forwarding. What is more, we propose an energy-efficient multi-hop routing protocol executed by BS for inter-cluster communication. Our strategy is making the most of BS's energy, so the node energy in the network is saved furthest. Simulation results show that EEMR clearly prolongs the network lifetime over HEED.

High delivery ratio with low energy consumption and transmission delay is one of design challenges for wireless sensor network routing protocol. In this paper, we proposed a grid-based distributed multi-hop routing protocol (GDRP) for wireless sensor network. At one time there is only one node is selected as grid head per grid and the remaining nodes perform grid head tasks by rotating dynamically. For the sake of decreasing the energy consumed by grid heads, the inter-grid communication uses multi-hop routing pattern. In GDRP each grid head executes a distributed algorithm and chooses an optimal next h-hop routing path independently according to the routing cost, distance and residual energy of neighboring grid heads. The experiment results show GDRP balances energy consumption well, thus leads to a high data delivery ratio, low transmission delay and prolonged network lifetime.