HEED: a hybrid, energy-efficient, distributed clustering approach for ad hoc sensor networks

Topology control in a sensor network balances load on sensor nodes and increases network scalability and lifetime. Clustering sensor nodes is an effective topology control approach. We propose a novel distributed clustering approach for long-lived ad hoc sensor networks. Our proposed approach does not make any assumptions about the presence of infrastructure or about node capabilities, other than the availability of multiple power levels in sensor nodes. We present a protocol, HEED (Hybrid Energy-Efficient Distributed clustering), that periodically selects cluster heads according to a hybrid of the node residual energy and a secondary parameter, such as node proximity to its neighbors or node degree. HEED terminates in O(1) iterations, incurs low message overhead, and achieves fairly uniform cluster head distribution across the network. We prove that, with appropriate bounds on node density and intracluster and intercluster transmission ranges, HEED can asymptotically almost surely guarantee connectivity of clustered networks. Simulation results demonstrate that our proposed approach is effective in prolonging the network lifetime and supporting scalable data aggregation.     

Fault‐tolerance in wireless ad hoc networks: bi‐connectivity through movement of removable nodes

For a wireless ad hoc network to achieve fault‐tolerance, it is desired that the network is bi‐connected. This means that each pair of nodes in the network have at least two node‐disjoint paths between them, and thus, failure at any single node does not partition the network. In other words, in a bi‐connected network, there is no cut‐node (defined as a node such that the removal of it partitions the network). To make a connected but not bi‐connected network become bi‐connected, actions should be taken such that all cut‐nodes become non‐cut‐nodes. In this research, we propose to deal with cut‐nodes from a new perspective. Specifically, we first introduce a new concept of removable node, defined as a non‐cut‐node such that the removal of it does not generate any new cut‐node in the network. Then, we propose to move a removable node to a new location around a cut‐node. In this way, the cut‐node becomes a non‐cut‐node, that is, the failure of it does not partition the network anymore. Algorithms are provided (i) to identify removable nodes; (ii) to match cut‐nodes with a feasible set of removable nodes, in which all nodes can be simultaneously removed from the network without generating any new cut‐node in the network; and (iii) to derive the final location of a removable node such that its movement distance is the shortest and the associated cut‐node becomes a non‐cut‐node. The proposed algorithms do not guarantee the final bi‐connectivity but have the merits of a large success rate (almost 100% in the simulation), a small number of moved nodes, and a short total movement distance. In addition, the proposed algorithms are shown to be effective even when there are a large portion of fixed nodes in the network. Copyright © 2011 John Wiley & Sons, Ltd.     

New nodal design for high throughput data vortex optical interconnection network

This paper proposes a new three input nodal structure within the data vortex packet switched interconnection network. With additional optical switches, the modified architecture allows for two input packets in addition to a buffered packet to be processed simultaneously within a routing node. A much higher degree of parallel processing is allowed in comparison to previously proposed enhanced buffer node with two input processing or the original network node with single input processing. Unlike the previous contention prevention mechanism, the new network operates by introducing the packet blocking within the node if no exit path is available. This eliminates the traffic control signaling and the strict timing alignment associated with the routing paths which simplifies the overall network implementation. This study shows that both data throughput and the latency performance are improved significantly within the new network. The study compares the three input node with the two input node as well as the original single input data vortex node. Due to additional switch count and nodal cost, networks that support the same I/O ports and of the same cost are compared for a fair comparison. The limitation introduced by the blocking rate is also addressed. The study has shown that under reasonable traffic and network condition, the blocking rate can be kept very low without introducing complex controls and management for dropped packets. As previous architectures require operation under saturation point, the proposed architecture should also operate at reasonable level of network redundancy to avoid excessive packet drop. This study provides guidance and criteria on the proposed three input network design and operation for feasible applications. The proposed network provides an attractive alternative to the previous architectures for higher throughput and lower latency performance.     

Exploiting agent mobility for large-scale network monitoring

As networks become pervasive, the importance of efficient information gathering for purposes such as monitoring, fault diagnosis, and performance evaluation increases. Distributed monitoring systems based on either management protocols such as SNMP or distributed object technologies such as CORBA can cope with scalability problems only to a limited extent. They are not well suited to systems that are both very large and highly dynamic because the monitoring logic, although possibly distributed, is statically predefined at design time. This article presents an active distributed monitoring system based on mobile agents. Agents act as area monitors not bound to any particular network node that can "sense" the network, estimate better locations, and migrate in order to pursue location optimality. Simulations demonstrate the capability of this approach to cope with large-scale systems and changing network conditions     

SeRWA: A secure routing protocol against wormhole attacks in sensor networks

A wormhole attack is particularly harmful against routing in sensor networks where an attacker receives packets at one location in the network, tunnels and then replays them at another remote location in the network. A wormhole attack can be easily launched by an attacker without compromising any sensor nodes. Since most of the routing protocols do not have mechanisms to defend the network against wormhole attacks, the route request can be tunneled to the target area by the attacker through wormholes. Thus, the sensor nodes in the target area build the route through the attacker. Later, the attacker can tamper the data, messages, or selectively forward data messages to disrupt the functions of the sensor network. Researchers have used some special hardware such as the directional antenna and the precise synchronized clock to defend the sensor network against wormhole attacks during the neighbor discovery process. In this paper, we propose a Secure Routing protocol against wormhole attacks in sensor networks (SeRWA). SeRWA protocol avoids using any special hardware such as the directional antenna and the precise synchronized clock to detect a wormhole. Moreover, it provides a real secure route against the wormhole attack. Simulation results show that SeRWA protocol only has very small false positives for wormhole detection during the neighbor discovery process (less than 10%). The average energy usage at each node for SeRWA protocol during the neighbor discovery and route discovery is below 25 mJ, which is much lower than the available energy (15 kJ) at each node. The cost analysis shows that SeRWA protocol only needs small memory usage at each node (below 14 kB if each node has 20 neighbors), which is suitable for the sensor network.     

A 200 Mbit/s Synchronous TDM Loop Optical LAN Suitable for Multiservice Integration

This paper describes a 200 Mbit/s multiservice optical local area network (LAN) using a synchronous TDM loop structure. The LAN consists of a central supervisory node and multiple service nodes connected by an optical fiber loop. Each service node supports communication channels which have access to allocated time slots in TDM frames continuously circulating on the loop. Multiple independent communication paths of various speeds up to 140 Mbits/s and various modes including point-to-point, ring, and multicast, can be provided between the channels on the loop. The ring will be useful to support ring networks, such as a token ring. The structure of this LAN is quite suitable for integration of multiple services, including video, image, data, and voice, since each service can independently choose its own speed, access method, and mode. In this development, various LSI-based high-speed hardware technologies including compact E/O and O/E modules, GaAs 4 × 4 matrix switch LSI's, and high-speed TDM-processor LSI's, which are versatilely applicable to high-speed LAN's ranging from 100 Mbits/s up to 560 Mbits/s, have been successfully introduced and compact LAN equipment has been obtained. This paper deals mainly with the system and hardware structure of this LAN, together with high-speed hardware technologies. An outline of firmware and network operation, and an application example are also described.     

Energy efficient fault-tolerant multipath routing scheme for wireless sensor networks

In wireless sensor network （MSN）, reliability is the main issue to design any routing technique. To design a comprehensive reliable wireless sensor network, it is essential to consider node failure and energy constrain as inevitable phenomena. In this paper we present energy efficient node fault diagnosis and recovery for wireless sensor networks referred as energy efficient fault tolerant multipath routing scheme for wireless sensor network. The scheme is based on multipath data routing. One shortest path is used for main data routing in our scheme and other two backup paths are used as alternative path for faulty network and to handle the overloaded traffic on main channel. Shortest pat data routing ensures energy efficient data routing. Extensive simulation results have revealed that the performance of the proposed scheme is energy efficient and can tolerates more than 60% of fault.     

Emergint:一种支持多节点并发动态增删的P2P路由算法

针对P2P网络动态构建问题,提出了一种能够支持多节点并发动态加入和退出的P2P路由算法.该算法具有如下特点:(1)自治性:节点的增删不需要统一控制;(2)动态性:节点的增删不影响其他节点路由过程的正确性;(3)并发性:多节点可以同时加入和退出系统,彼此不干扰.该算法的路由延迟为logN.模拟测试结果表明:该算法的平均RDP为1.5,增删节点的代价为O(logN).     

Performance Evaluation of a Power Management Scheme for Disruption Tolerant Network

Disruption tolerant network (DTN) is characterized by frequent partitions and intermittent connectivity. Power management issue in such networks is challenging. Existing power management schemes for wireless networks cannot be directly applied to DTNs because they assume the networks are well-connected. Since the network connectivity opportunities are rare, any power management scheme deployed in DTNs should not worsen the existing network connectivity. In this paper, we design a power management scheme called context-aware power management scheme (CAPM) for DTNs. Our CAPM scheme has an adaptive on period feature that allows it to achieve high delivery ratio and low delivery latency when used with Prophet, a recently proposed DTN routing scheme. Via simulations, we evaluate the performance of the CAPM scheme when used with the Prophet routing scheme in different scenarios e.g. different traffic load, node speeds and sleep patterns. Our evaluation results indicate that the CAPM scheme is very promising in providing energy saving (as high as 80%) without degrading much the data delivery performance.     

Radio frequency identification: technologies,applications, and research issues

A radio frequency identification (RFID) system is a special kind of sensor network to identify an object or a person using radio frequency transmission. A typical RFID system includes transponders (tags) and interrogators (readers): tags are attached to objects/persons, and readers communicate with the tags in their transmission ranges via radio signals. RFID systems have been gaining more and more popularity in areas such as supply chain management, automated identification systems, and any place requiring identifications of products or people. RFID technology is better than barcode in many ways, and may totally replace barcode in the future if certain technologies can be achieved such as low cost and protection of personal privacy. This paper provides a technology survey of RFID systems and various RFID applications. We also discuss five critical research issues: cost control, energy efficiency, privacy issue, multiple readers' interference, and security issue. Copyright © 2006 John Wiley & Sons, Ltd.     

求解时间窗口网络中前k条最短路径的方法

在一个时间窗口网络中寻找前k条最短路径是一项具有挑战性的任务.在时间窗口网络中，一个节点可能只有在某些特定的时间窗口内才能通行.现有的研究大都假设运动体可以立即通过可通行节点，或者在暂不可通行节点处等待直到未来时间窗口的开始时刻才通过.本文针对一个更一般的时间窗口情况，其中运动体一旦到达节点，可以选择在节点的时间窗口中的任何离散时刻通过该节点.本文将这样的时间窗口网络称为拓展时间窗口网络，其解空间大小和复杂程度都显著增加.通过模拟水面上的自然涟漪扩散现象，本文提出了一种有效的涟漪扩散算法，用于求解拓展时间窗口网络中的前k条最短路径.除了一对一问题之外，涟漪扩散算法（ripple spreading algorithm，RSA）还扩展到一对多问题.在一对多问题中，需要找到从给定起点到网络中的每个其他节点的所有前k条最短路径.新方法具有最优性的理论保证，其计算复杂度仅为O（k×N_ATU×N_L），其中N_L是网络中链接的数量，N_ATU是涟漪通过链接平均所需的仿真时间单位数.实验结果证明了RSA的有效性.     

Identification of faulty links in dynamic-routed networks

The authors present a maximum a posteriori method to identify faulty links in a communication network. A designated network node with management responsibilities determines a fault has occurred due to its inability to communicate with certain other nodes. Given this information as well as the information that it can communicate with another specified set of nodes, one would like to identify as quickly as possible a ranked list of the most probable failed network links. The authors also indicate how the method might be extended to the identification of most probable faulty network resources in a more abstract (higher level) model of a network, including, for example, an object-oriented model     

Fault Diagnosis of Nonlinear Analog Circuits Using Neural Networks with Wavelet and Fourier Transforms as Preprocessors

A neural-network based analog fault diagnostic system is developed for nonlinear circuits. This system uses wavelet and Fourier transforms, normalization and principal component analysis as preprocessors to extract an optimal number of features from the circuit node voltages. These features are then used to train a neural network to diagnose soft and hard faulty components in nonlinear circuits. Our neural network architecture has as many outputs as there are fault classes where these outputs estimate the probabilities that input features belong to different fault classes. Application of this system to two sample circuits using SPICE simulations shows its capability to correctly classify soft and hard faulty components in 95% of the test data. The accuracy of our proposed system on test data to diagnose a circuit as faulty or fault-free, without identifying the fault classes, is 99%. Because of poor diagnostic accuracy of backpropagation neural networks reported in the literature (Yu et al., Electron. Lett., Vol. 30, 1994), it has been suggested that such an architecture is not suitable for analog fault diagnosis (Yang et al., IEEE Trans. on CAD, Vol. 19, 2000). The results of the work presented here clearly do not support this claim and indicate this architecture can provide a robust fault diagnostic system.     

A Scalable-Adaptive Snack Routing Strategy (SRS) for Semi-Administrated Mobile Ad Hoc Networks (SAMANETs)

Recently, Mobile Ad Hoc networks (MANETs) are growing in popularity and importance. They present a possible communication among a set of mobile nodes with no need for either a pre-established infrastructure or a central administration. However, in order to guarantee an efficient communication among network nodes, efficient routing algorithms should be established. Routing plays the central role in providing ubiquitous network communications services in such dynamic networks. The problem is further aggravated through the node mobility as any node may move at any time without notice. Several routing protocols had been proposed; however, most of them suffer from control packet flooding, which results in a scalability problem. In this paper, a new routing strategy for MANETs is proposed which is called Snack Routing Strategy (SRS). The basic idea of SRS is to continuously inform the network mobile nodes with any changes in the network topology without overloading the network by a huge amount of control messages. SRS is a hybrid routing strategy that relies on Learning by accumulation, hence, new routes can be discovered by learning the accumulative data stored in the nodes routing tables by several foraging artificial snacks. SRS uses no periodic routing advertisement messages but uses artificial snacks instead, thereby reducing the network bandwidth overhead and minimizing end-to-end transmission delay. SRS has been compared against two well known protocols AODV and DSR. Experimental results have shown that SRS outperforms both AODV and DSR as it introduces the minimal routing overheads.     

Single-Link Failure Detection in All-Optical Networks Using Monitoring Cycles and Paths

In this paper, we consider the problem of fault localization in all-optical networks. We introduce the concept of monitoring cycles (MCs) and monitoring paths (MPs) for unique identification of single-link failures. MCs and MPs are required to pass through one or more monitoring locations. They are constructed such that any single-link failure results in the failure of a unique combination of MCs and MPs that pass through the monitoring location(s). For a network with only one monitoring location, we prove that three-edge connectivity is a necessary and sufficient condition for constructing MCs that uniquely identify any single-link failure in the network. For this case, we formulate the problem of constructing MCs as an integer linear program (ILP). We also develop heuristic approaches for constructing MCs in the presence of one or more monitoring locations. For an arbitrary network (not necessarily three-edge connected), we describe a fault localization technique that uses both MPs and MCs and that employs multiple monitoring locations. We also provide a linear-time algorithm to compute the minimum number of required monitoring locations. Through extensive simulations, we demonstrate the effectiveness of the proposed monitoring technique.      

基于动态多网段的数据链网络监视与管理系统的设计与实现

提出了一种可动态配置 IP 跨网段的数据链网络监视管理系统的设计与实现方法， 该系统应用层采用 B/S 与 C/S 的混合架构，网络层通过软件定义网络(SDN)集群实现数据链网内成员间的跨网段交互的动态可配置。系统功能涉及平台身份控制、方案管理、跨网段参数控制、 多网段内节点状态监视等技术。所设计方法的应用结果表明，该系统可以为数据链网络提供可靠的监视与管理服务，任意节点间路由关系动态可配置，提高数据链各节点的灵活性，满足项目应用要求。     

Secured routing in wireless sensor networks using fault‐free and trusted nodes

Wireless sensor network (WSN) should be designed such that it is able to identify the faulty nodes, rectify the faults, identify compromised nodes from various security threats, and transmit the sensed data securely to the sink node under faulty conditions. In this paper, we propose an idea of integrating fault tolerance and secured routing mechanism in WSN named as fault tolerant secured routing: an integrated approach (FASRI) that establishes secured routes from source to sink node even under faulty node conditions. Faulty nodes are identified using battery power and interference models. Trustworthy nodes (non‐compromised) among fault‐free nodes are identified by using agent‐based trust model. Finally, the data are securely routed through fault‐free non‐compromised nodes to sink. Performance evaluation through simulation is carried out for packet delivery ratio, hit rate, computation overhead, communication overhead, compromised node detection ratio, end‐to‐end delay, memory overhead, and agent overhead. We compared simulation results of FASRI with three schemes, namely multi‐version multi‐path (MVMP), intrusion/fault tolerant routing protocol (IFRP) in WSN, and active node‐based fault tolerance using battery power and interference model (AFTBI) for various measures and found that there is a performance improvement in FASRI compared with MVMP, IFRP, and AFTBI. Copyright © 2014 John Wiley & Sons, Ltd.     

A novel fault detection and recovery technique for cluster‐based underwater wireless sensor networks

The performance of underwater wireless sensor network gets affected by the working of a cluster in the network. The cluster head (CH) or cluster member (CM) fails because of energy depletion or hardware errors that increase delay and message overhead of the network. To recover the affected cluster, a technique is required to identify the failed CH or CM. We propose a fault detection and recovery technique (FDRT) for a cluster‐based network in this paper. Primarily, while selecting the CH, a backup cluster head (BCH) is selected using fuzzy logic technique based on parameters such as node density, residual energy, load, distance to sink, and link quality. Then, failure of CH, BCH, and CM is detected. If fault is detected at CH, then the BCH will start performing the task of failed CH. Simultaneously, when BCH failed, any other CM will be elected as BCH. If any of the CM appears to be nonperforming, then CH will detect the communication failure and request BCH to transfer the data from the failed CM to CH. The comparison of proposed FDRT is performed with existing FDRTs EDETA, RCH, and SDMCGC on the basis of packet drop, end‐to‐end delay, energy consumption, and delivery ratio of data packets. By simulation results, it is shown that FDRT for cluster‐based underwater wireless sensor network results in quicker detection of failures and recovery of the network along with the reduction in energy consumption, thereby increasing the lifespan of the network.     

An approach for failure recognition in IP‐based industrial control networks and systems

Industrial control networks (ICNs) and systems support robust communications of devices in process control or manufacturing environments. ICN proprietary protocols are being migrated to Ethernet/IP networks in order to merge various different types of networks into a single common network. ICNs are deployed in mission‐critical operations, which require a maximum level of network stability. Network stability is often described using several categories of network performance quality‐of‐service metrics, such as throughput, delay, and loss measurements. The question arises as to whether these network performance metrics are sufficient to run valuable diagnostics of ICN components and their communications. Any abnormal decision with respect to typical IP traffic behavior does not necessarily coincide with ICN fault cases. A precise and specific diagnostic technique for ICNs is required to remove the uncertainty in detecting problems. However, existing Ethernet/IP diagnosis tools have not been able to fully handle fault symptoms and mainly focus on network diagnostics rather than process or device diagnostics. This paper demonstrates that the absence of advanced fault diagnosis techniques leads to the development of new methodologies that are suitazble for ICN. We describe unique traffic characteristics and categorize the faults of ICN. We also propose a fault diagnosis, prediction, and adaptive decision methodologies, and verify them with real‐world ICN data from the steel‐making company POSCO. Our experience in developing the fault diagnosis system provides a firm guideline to understand the fault management mechanisms in large ICNs. Copyright © 2012 John Wiley & Sons, Ltd.