The Controller-Area-Network (CAN) Bus has become a vulnerable target because of its ability to manage real-time plaintext vehicle data. Vulnerabilities include Man-in-the-Middle (MitM), Sniffing, Spoofing, Replay, Denial-of-Service (DoS), and other attacks originating from embedded malware or external attacks from the connected Internet. The existing work for CAN Bus enhancement relies on a centralized authority, which causes a single point of security failure. This work discusses decentralized CAN Bus security through a blockchain-reminiscent method, improving the security against CAN Bus attacks. A lab test-bed is built using different Electronic Control Units (ECUs) for performance validation, including ECUs manufactured by Microchip Technology. Instead of simulation, which is employed in other approaches, security attacks are conducted on a Buick Encore vehicle. The results from this study exhibit that VehChain protects CAN Frame data from Sniffing, Spoofing, Replay, and Denial of Service (DoS) attacks by utilizing secure Hashed Message Authentication Codes (HMACs), message counters, and key synchronization.

To enable advanced manufacturing applications, reliable and low-latency communication is crucial between the sensors/actuators and the central controller. However, the current wireless communication protocols fall short in meeting these stringent requirements, thereby hindering the use of wireless sensors despite their low cost, flexibility, and productivity benefits compared to wired communication. This paper proposes a new wireless MAC protocol called L2Wireless that uses cooperative relaying and network coding to address these issues. Our goal is to design a protocol that can support at least ten sensors/actuators in a factory cell while achieving the desired latency and reliability. The L2Wireless MAC layer uses cooperative relay and network coding to ensure successful information exchange between the controller and actuators with constrained latency and reliability. We use practical channel measurements from NIST and industrial wireless systems radio propagation measurements to simulate the performance. Our results indicate that the L2Wireless protocol can support a sufficient number of devices within a work cell while simultaneously achieving the desired latency and reliability using cooperative relaying and network coding. Additionally, we show that the extra bit error rate (BER) required to achieve low latency and high reliability is minimal.

Recently, large-scale networks attract significant attention to analyze and extract the hidden information of big data. Toward this end, graph embedding is a method to embed a high dimensional graph into a much lower dimensional vector space while maximally preserving the structural information of the original network. However, effective graph embedding is particularly challenging when massive graph data are generated and processed for real-time applications. In this paper, we address this challenge and propose a new real-time and distributed graph embedding algorithm (RTDGE) that is capable of distributively embedding a large-scale graph in a streaming fashion. Specifically, our RTDGE consists of the following components: (1) a graph partition scheme that divides all edges into distinct subgraphs, where vertices are associated with edges and may belong to several subgraphs; (2) a dynamic negative sampling (DNS) method that updates the embedded vectors in real-time; and (3) an unsupervised global aggregation scheme that combines all locally embedded vectors into a global vector space. Furthermore, we also build a real-time distributed graph embedding platform based on Apache Kafka and Apache Storm. Extensive experimental results show that RTDGE outperforms existing solutions in terms of graph embedding efficiency and accuracy.

Storing large amounts of data is challenging as it requires large reliable storage space. Currently, peer-to-peer (P2P) systems have been implemented for this purpose. However, these systems provide no guarantee of data retrieval as the data availability is determined by the interest of the users. On the other hand, cloud storage systems, built on top of a pool of powerful servers, can provide reliable data storage; however, they are costly and vulnerable to privacy leakage. This paper proposes a novel distributed data storage system based on the social networks. Particularly, our system utilizes the social information of the users to find the potential storage nodes. The storage nodes are then selected based on the social ties with the data owner. In order to quickly obtain the potential storage nodes, we provide an efficient algorithm to search and compute the social ties in the social networks. The system performance is verified through both theoretical analysis and simulations. The results show that data stored in our proposed system is reliable and stable given the random nature of storage nodes joining and leaving the system. A marginal performance gain is achieved in comparison to P2P systems.

Abstract In a static wireless sensor network (WSN), sensors close to the base station (BS) run out of energy at a much faster rate than sensors in other parts of the network. This is because the sensor close to the BS always relays the data for other sensors, resulting in an unequal distribution of network residual energy. In this paper, we propose a scheme for enhancing the network lifetime using multiple mobile cluster heads (CHs) that can move in the WSN in a controllable manner. The CH controllably moves toward the energy‐rich sensors or the event area, offering the benefits of maintaining the remaining energy more evenly, or eliminating multihop transmission. Therefore, the proposed scheme increases the network lifetime. We theoretically analyze the energy consumption in our scheme and propose three heuristical mobility strategies. We further study the collaboration among CHs in order to maintain their connectivity to the BS to ensure the delay requirement for real‐time applications. Simulation shows that network lifetime is increased by upto 75% over existing approach by making CHs always move toward a stable equilibrium point. Our connectivity algorithm provides a best case improvement of 40% in transmission delays over existing schemes. Copyright © 2009 John Wiley & Sons, Ltd.

A Wireless Mesh Network (WMN) is connected by multiple wireless mesh routers that are able to operate multiple channels for increased network capacity. As other wireless networks, the network capacity is a fundamental issue in the WMN. The analytical results in this paper show that the upper bound of network capacity lambda scales Theta(Wf/cradicn) if the number of infrastructure nodes m is significantly less than the number of MRs (n). Only when m asymptotically grows with n, the network capacity achieves Theta(Wfm/(n(2-P)c)), resulting in significant capacity gain. We shows the WMN upper bounds of the infrastructure network capacity eta and its ad hoc capacity zeta as well.

Wireless mesh network (WMN) technology extends the service coverage by supporting multi-hop communication and enhances the network capacity by utilizing multi-radio and multichannel. The number of multiple channels is essential for the implementation and the efficiency of channel assignment. While the number of channels is not sufficient, channel assignment needs to consider the channel sharing at certain mesh routers (MRs). The distribution of traffic flows in the network greatly affects the channel assignment. Different to a mobile ad hoc network (MANET), the traffic in a WMN is predominated by the Internet traffic. In this paper, we analyze the number of channels for a feasible conflict free channel assignment in such a network. We also propose a flow-based channel assignment in the channel constrained situation by implementing channel mergence algorithm so that MRs can appropriately share the channel resource. Extensive simulations are performed to illustrate the effectiveness of our proposed scheme.

In the recent years, wireless mesh network (WMN) has evolved as a new paradigm for broadband wireless Internet access. The self-configurability, open wireless infrastructure, and different management styles of WMN make them vulnerable to malicious attackers. As a first step to secure WMNs, it is critical to incorporate an authentication mechanism for mesh clients. The existing proposals are primarily based on public key certificates, which incur considerable overhead in signature verification. We propose a network layer authentication mechanism called Merkle Tree based Mesh Authentication Protocol (MT-MAP) for WMNs. It incorporates inexpensive hash operations using Merkle tree to authenticate single/multihop mesh clients. We also show how the use of hash tree facilitates fast and periodic refresh of authentication certificates. Finally, we present a security analysis of MT-MAP against impersonation and replay attacks.

In a wireless mesh network (WMN), mesh routers (MRs) are interconnected by wireless links and form a wireless backbone to provide ubiquitous high-speed Internet connectivity for mobile clients (MCs). The wireless backbone is tightly integrated with the Internet by a special kind of nodes called as Internet gateways (IGWs). Even though the capacity of WMN can be improved by equipping the MRs with multiple radios working at non-overlapping channels, the deployment of IGW is critical to the network performance of WMN. In this paper, we address the IGW placement problem based on a hierarchical cluster based architecture. The problem is first formulated as a linear program (LP) issue, then some heuristic algorithms are developed. Our simulation results show the effectiveness of the proposed algorithms.

The network performance such as node capacity in a wireless mesh network (WMN) could be limited due to inappropriate interface configuration. Mesh routers (MRs) with heavy load may suffer from interface shortage. On the other hand, a MR with less load experiences a low utilization of interfaces. In this paper, we advocate heterogeneous interface configuration to appropriately configure the MRs' interfaces. It achieves the purpose of minimizing the total number of interfaces in a WMN while guaranteeing the various constraints such as traffic demand. We first formulate the problem when the traffic demand is non-uniformly distributed. On the basis of theoretical analysis, we propose a heuristic algorithm to find a ";close-to- optimal"; solution for interface configuration. Our simulation shows the effectiveness of our proposed heuristic algorithm.

Intrusion detection in Wireless Sensor Network (WSN) is of practical interest in many applications such as detecting an intruder in a battlefield. The intrusion detection is defined as a mechanism for a WSN to detect the existence of inappropriate, incorrect, or anomalous moving attackers. For this purpose, it is a fundamental issue to characterize the WSN parameters such as node density and sensing range in terms of a desirable detection probability. In this paper, we consider this issue according to two WSN models: homogeneous and heterogeneous WSN. Furthermore, we derive the detection probability by considering two sensing models: single-singing detection and multiple-sensing detection. In addition, we discuss the network connectivity and broadcast reachability, which are necessary conditions to ensure the corresponding detection probability in a WSN. Our simulation results validate the analytical values for both homogeneous and heterogeneous WSNs.

A wireless sensor network (WSN) has to maintain a desirable sensing coverage and periodically report sensed data to the administrative center (i.e., base station) and the reporting period may range from months to years. Coverage and lifetime are two paramount problems in a WSN due to constraint of associated battery power. All previous theoretical analysis on the coverage and lifetime is primarily focused on the random uniform distribution of sensors or some specific network scenarios (e.g., a controllable WSN). In this paper, we provide an analytical framework for the coverage and lifetime of a WSN that follows a two-dimensional Gaussian distribution. We also study the coverage and lifetime when the dimensions of Gaussian dispersion (i.e., x, y) admit different Gaussian parameters (i.e., standard deviation, $\sigma_x \neq\sigma_y$). We identify intrinsic properties of coverage/lifetime in terms of Gaussian distribution parameters, which is a fundamental issue in designing a WSN. Following the results obtained, we further determine the sensor deployment strategies for a WSN that could satisfy a predefined coverage and lifetime. Two deployment algorithms are developed based on using our analytical models and are shown to effectively increase the WSN lifetime.

Abstract Integration of ad hoc networks with the Internet provides global Internet connectivity for ad hoc hosts through the coordination of mobile IP and ad hoc protocols. In a pure ad hoc network, it is difficult to establish trust relationship between two ad hoc hosts due to lack of infrastructure or centralized administration. In this paper, an infrastructure‐supported and distributed authentication protocol is proposed to enhance trust relationships amongst ad hoc hosts. In addition, an effective secure routing protocol (SRP) is discussed to protect the multi‐hop route for Internet and ad hoc communication. In the integrated ad hoc networks with Internet accessibility, the ad hoc routing security deployed with the help of infrastructure has a fundamental impact on ad hoc hosts in term of Internet access, integrity, and authentication. Both analysis and simulation results demonstrate the effectiveness of the proposed security protocol. Copyright © 2007 John Wiley & Sons, Ltd.

This paper identifies faulty sensor(s) in a polynomial-based data aggregation scenario, TREG proposed in our earlier work. In TREG, function approximation is performed over the entire range of data and only coefficients of a polynomial (P) are passed instead of aggregated data. Performing further mathematical operations on the calculated P can identify the maximum (max) and minimum (min) values of the sensed attribute and their locations. Therefore, if any sensor reports a data value outside the [min, max] range, it can be identified as a faulty sensor. We achieve the following goals: (1) uncorrelated readings from a specific sensor helps in detecting a faulty sensor, (2) faulty sensors are detected near the source and isolated preventing them from affecting the accuracy of the overall aggregated data and reducing the overall delay. Results show that a faulty sensor can be detected with an average accuracy of 94 %. With increase in node density, accuracy in faulty sensor detection improves as more nodes are able to report the information to their nearest tree node.

We propose a polynomial-based scheme that addresses the problem of event region detection (PERD) for wireless sensor networks (WSNs). Nodes of an aggregation tree perform function approximation of the event using multivariate polynomial regression. Only the coefficients of this polynomial are then transmitted up the tree instead of aggregated data. PERD includes two components: event recognition and event report with boundary detection. In addition, PERD is capable of detecting single event or multiple events simultaneously occurring in the WSN. Since PERD is implemented over a polynomial tree on a WSN in a distributed manner, it is easily scalable and computation overhead is very light. Results reveal that event(s) can be detected by PERD with error in detection remaining almost constant achieving a percentage error within a threshold of 10% with increase in communication range.

Unlike ad hoc networks where traffic is randomly distributed among every pair of nodes, the traffic in wireless mesh networks (WMNs) is predominantly toward or from the Internet Gateways (IGWs)for Internet services. Due to this, interference and collision are more serious in the Mesh Router (MRs) closer to the IGWs and the Internet throughput of the network is limited by the number of orthogonal channels and radios of the IGW. In this paper, we propose a channel assignment scheme which exploits a tree-based topology in WMNs and implements a heuristic channel assignment algorithm, aiming to achieve the maximal Internet throughput. The channels are sequentially assigned level by level in the tree, starting from the IGW. The simulation results show that the network using this scheme achieve the Internet throughput close to the maximal capacity of IGW.

The allocation of channel bandwidth without significantly increasing the interference among existing users is a challenge for the future UWB networks. Our research work presents a novel rake optimization and power aware scheduling (ROPAS) architecture for UWB networks. We propose to use cognitive radio (CR) for dynamic channel allocation among the requesting users while limiting the average power transmitted in each sub-band. In our proposed ROPAS architecture, dynamic channel allocation is achieved by a CR-based cross-layer design between the PHY and medium access control (MAC) layers. The joint power control and link scheduling in the MAC layer reduces adjacent channel and multi-access interference introduced by multiple access of the links. Furthermore, the Rake optimization with its strategic selection of propagation paths achieves the minimal bit-error rate (BER) at the rake receiver by mixed integer programming. Our simulated-based performance evaluation confirms the effectiveness and novelty of our proposed ROPAS architecture.

In a wireless mesh network (WMN), mesh routers (MRs) are interconnected by wireless links and form a wireless backbone to provide ubiquitous high-speed Internet connectivity for mobile clients. The wireless backbone is tightly integrated with the Internet by nodes called as Internet gateways (IGWs). In this paper, we address the IGW deployment problem which is shown to be NP-hard. We first formulate it as a linear program (LP) issue, then develop two heuristic algorithms for the purpose of cost-efficient IGW deployment. We further compare our algorithms with a leading approach by extensive simulations. Our analysis shows the effectiveness of the proposed algorithms.

The placement of mesh routers (MRs) in building a wireless mesh network (WMN) is the first step to ensure the desired network performance. Given a network domain, the fundamental issue in placing MRs is to find the minimal configuration of MRs so as to satisfy the network coverage, connectivity, and Internet traffic demand. In this paper, the problem is addressed under a constraint network model in which the traffic demand is non-uniformly distributed and the candidate positions for MRs are pre-decided. After formulating the MR placement problem, we first provide the theoretical analysis to validate the traffic demand and determine the optimal position of Internet gateway (IGW). To reduce complexity of determining the locations of MRs while satisfying the traffic constraint, we propose an effective heuristic algorithm to obtain an close-to-optimal solution. Finally, our simulation results verify our analytical model and show the effectiveness of our proposed algorithm.

This paper proposes a scheme for enhancement of network Lifetime using MObile Clusterheads (LIMOC) in a wireless sensor network (WSN). The low energy, static sensor nodes sense physical parameters and route the data to the highly energy-rich nodes called ClusterHeads (CHs) which are mobile and can transmit data directly to the base station (BS). A collaborative strategy among the CHs increases the lifetime (hence residual energy) of the network further. Simulation has shown that residual energy of the network can be improved by 45% by making the CHs always move towards the event in an event-driven network. For general cases, increased energy savings is obtained by making the CH move towards the center of equilibrium w.r.t. to both the total residual energy and data flow of the network.

This paper proposes a scheme for domain partition to achieve the tradeoff between load-balancing and inter-domain mobility to reduce the negative impact of the host mobility. The load-balancing scheme for domains includes: an initialization procedure to divide a mesh network into domains, and a load adjustment procedure to rebalance the traffic load of neighboring domains when required. Moreover, the proposed scheme provides inter-domain mobility in support of multi-hop communication with the multi-hop cellular IP (MCIP) mobility protocol. Our experimental results show that the proposed protocol effectively controls the migration of mesh routers as well as mobile stations.

Multi-hop cellular networks offer attractive benefits for the next generation of wireless communication by integrating ad hoc relaying to cellular networks. However, most of the existing architectures and protocols for multi-hop cellular networks suffer from a variety of security threats in an adversarial environment. The existing architectures and protocols are not capable of providing end-to-end security protection for mobile users. A generalized multi-hop security protocol (GMSP) is proposed in this paper to achieve an effective route discovery protection from a range of potential security threats. The proposed multi-hop security protocol integrates mobile IP security and ad hoc security schemes. Moreover, the proposed protocol is flexible enough for fulfilling security protection for most existing heterogeneous multi-hop cellular architectures

This paper proposes a new heterogeneous multi-hop cellular IP (MCIP) network that integrates multi-hop communication with cellular IP. MCIP increases the coverage of the wireless network and improves the network robustness against adverse propagation phenomena by supporting communication in dead zones and areas with poor radio coverage. MCIP includes three components: location management, connection management and route reconfiguration. Location management is responsible for maintaining the location information for mobile stations (MSs) in a local domain. Connection management establishes an initial path for data transmission and a route reconfiguration mechanism is proposed to take advantage of various multi-hop connection alternatives available based on terminal interfaces, network accessibility and topology. Our simulation results show that MCIP performs well in networks of various sizes.

Extending mobile IP to ad hoc networks with the foreign agent (FA) acting as the bridge between the wired network and ad hoc networks can provide the global Internet connectivity for ad hoc hosts. The existing research in the area of the integrated wired and ad hoc network is carried out in a nonadversarial setting. This work proposes an effective solution to solve the security related problems encountered in these integrated networks. The proposed approach uses the modified minimal public based authentication protocol not only for mobility binding at the home agent (HA) but also for access control and route discovery. This security protocol also excludes malicious nodes from performing the ad hoc network routing. This paper focuses on preventing ad hoc hosts from the attacks of antiintegrity, anticonfidentiality, antiauthentication and duplication.

The integration of the Internet and ad hoc mobile hosts can be used to eliminate dead zones in wireless networks, and can also be used to extend the coverage of wireless networks. The integration enriches the application range of ad hoc networks. Earlier approaches for the integrated networks either provided only unidirectional global connectivity for ad hoc hosts or caused high overhead and delay for providing full bi-directional connections. In this paper, an enhanced DSDV (EDSDV) protocol is proposed for ad hoc networks. The EDSDV protocol is integrated with Mobile IP to provide full bi-directional Internet connectivity for ad hoc network hosts. This approach has smaller overhead for full bi-directional connectivity and also shorter average packet delay compared to other integration approaches.