基于神经网络的自组织传感器网络设计

多传感器目标跟踪是信息融合的一个重要研究内容。尽管已经有许多的融合算法,但目前对跟踪传感器的配置问题研究还很少,而这对于设计一个成功的UGS网络系统是必要的。本文设计了一种神经元阈值可调的自适应Hopfield网络,可以自组织地从整个网络中选取合适数目的传感器组成跟踪器,使整个系统的精度足够高,而使用的传感器数目尽可能少。仿真显示了算法的有效性。     

Two energy efficient algorithms for tracking objects in a sensor network

We propose two energy efficient algorithms for locating a target object moving in an area covered by a wireless ad hoc network. The first algorithm developed conserve energy by efficiently identifying sensor nodes, as Home Nodes, and use only local messages between neighboring nodes to follow the trail of the object. Since we avoid the long‐range transmission and maximize the localization, the algorithms reduce the communication cost. The dynamic nature of the second algorithm exploits the predefined parameters such as the object velocity. Our algorithm represents query shipping against the conventional data shipping as a means to reduce the amount of data being shipped across the network. Hence, it locates the objects over the network with minimal energy conservation using short‐range message transmissions. The performance analysis (both experimental and theoretical) shows the effectiveness of the two algorithms in comparison to another tracking algorithm. Copyright © 2006 John Wiley & Sons, Ltd.     

Fast Response PKC-Based Broadcast Authentication in Wireless Sensor Networks

Public Key-based (PKC) approaches have gained popularity in Wireless Sensor Network (WSN) broadcast authentication due to their simpler protocol operations, e.g., no synchronization and higher tolerance to node capture attack compared to symmetric key-based approaches. With PKC??s security strength, a sensor node that authenticates messages before forwarding them can detect a bogus message within the first hop. While this prevents forged traffic from wasting the sensor nodes?? energy, performing PKC operations in the limited computing-power sensor nodes can result in undesirably long message propagation time. At the other extreme, the sensor node can forward messages to other nodes prior to authenticating them. This approach diminishes propagation time with the trade-off of allowing forged messages to propagate through the network. To achieve swift and energy efficient broadcast operation, sensor nodes need to decide wisely when to forward first and when to authenticate first. In this paper, we present two new broadcast authentication schemes, called the key pool scheme and the key chain scheme, to solve this dilemma without any synchronization or periodic key redistribution. Both schemes utilize a Bloom filter and the distribution of secret keys among sensor nodes to create fast and capture-resistant PKC-based broadcast authentication protocols. Our NS-2 simulation results for a 3,000-node WSN confirm that broadcast delays of our protocol are only 46.7% and 39.4% slower than the forwarding-first scheme for the key pool and the key chain scheme respectively. At the same time, both protocols are an order of magnitude faster than the authentication-first scheme. The key pool scheme is able to keep forged message propagation to the minimal even when the majority of the nodes have been captured by the attacker. The key chain scheme has smaller transmission overhead than the key pool scheme at the expense of less resistance to node capturing. Two generic improvements to these schemes are also described. One reduces the marking limit on the Bloom filter vector (BFV), which makes it more difficult for an attacker to forge a BFV for a bogus message. The other limits broadcast forwarding to a spanning tree, which reduces the number of nodes forwarding bogus messages by one to two orders of magnitude depending on the percentage of compromised nodes. The first improvement can be applied to any BFV scheme, while the second is even more generally applicable.     

A Novel Energy-Aware Target Tracking Method by Reducing Active Nodes in Wireless Sensor Networks

Energy consumption is one of the main challenges in wireless sensor networks. Additionally, in target tracking algorithms, it is expected to have a longer lifetime for the network, when a better prediction algorithm is employed, since it activates fewer sensors in the network. Most target tracking methods activate a large number of nodes in sensor networks. This paper proposes a new tracking algorithm reducing the number of active nodes in both positioning and tracking by predicting the target deployment area in the next time interval according to some factors including the previous location of the target, the current speed and acceleration of the target without reducing the tracking performance. The proposed algorithm activates the sensor nodes available in the target area by predicting the target position in the next time interval. The problem of target loss is also considered and solved in the proposed tracking algorithm. In the numerical analysis, the number of nodes involved in target tracking, energy consumption and the network lifetime are compared with other tracking algorithms to show superiority of the proposed algorithm.     

Learning Automata Based Face-Aware Mobicast

Target tracking is one of the most popular applications of the wireless sensor networks. It can be accomplished using different approaches and algorithms, one of which is the spatiotemporal multicast protocol, called “mobicast”. In this protocol, it is assumed that the area around the moving target, called the delivery zone, is known at any given time during the operation of the network. The aim of the protocol is to awake sensor nodes, which will be within the delivery zone in the near future, to be prepared for tracking the approaching moving target. In this paper, we propose a novel mobicast algorithm, aiming at reducing the number of awakened sensor nodes. To this end, we equipped every sensor node with a learning automaton, which helps the node in determining the sensor nodes it must awaken. To evaluate the performance of the proposed algorithm, several experiments have been conducted. The results have shown that the proposed algorithm can significantly outperform other existing algorithms such as forward-zone constrained and FAR in terms of energy consumption, number of active nodes, number of exchanged packets and slack time.     

Topology Management Ensuring Reliability in Delay Sensitive Sensor Networks with Arbitrary Node Failures

The lifetime of a sensor network is influenced by the efficient utilization of the resource constrained sensor nodes. The tree-based data gathering offers good quality of service (QoS) for the running applications. However, data gathering at the sink reduces the network lifetime due to a fast failure of highly loaded nodes. Loss of connectivity and sensing coverage affect the performance of the applications that demand critical QoS. In this paper, a data gathering tree management scheme has been proposed to deal with arbitrary node failures in delay-sensitive sensor networks. A load-balanced distributed BFS tree construction procedure has been introduced for an efficient data gathering. Based on the initial tree construction, a tree maintenance scheme and an application message handler have been designed to ensure the reliable delivery of the application messages. The correctness of the proposed scheme has been verified both theoretically and with the help of simulation. The proposed scheme offers low overhead, enhanced network lifetime and good QoS in terms of delay and reliability of the application messages.     

基于强跟踪滤波的传感器目标跟踪算法

为了提高运动目标的跟踪精度,提出一种基于强跟踪滤波的传感器目标跟踪算法.首先通过传感器节点测量目标的状态值,并通过融合中心对信息进行融合,然后利用Cholesky分解技术变换成噪声独立的量化融合系统,并采用强跟踪滤波算法对目标状态进行估计,最后与其它目标跟踪算法进行对比实验.结果表明,本文算法不仅提高了目标跟踪的精度,而且具有更好的鲁棒性.     

Cluster Based Routing Protocol for Mobile Nodes in Wireless Sensor Network

Mobility of sensor nodes in wireless sensor network (WSN) has posed new challenges particularly in packet delivery ratio and energy consumption. Some real applications impose combined environments of fixed and mobile sensor nodes in the same network, while others demand a complete mobile sensors environment. Packet loss that occurs due to mobility of the sensor nodes is one of the main challenges which comes in parallel with energy consumption. In this paper, we use cross layer design between medium access control (MAC) and network layers to overcome these challenges. Thus, a cluster based routing protocol for mobile sensor nodes (CBR-Mobile) is proposed. The CBR-Mobile is mobility and traffic adaptive protocol. The timeslots assigned to the mobile sensor nodes that had moved out of the cluster or have not data to send will be reassigned to incoming sensor nodes within the cluster region. The protocol introduces two simple databases to achieve the mobility and traffic adaptively. The proposed protocol sends data to cluster heads in an efficient manner based on received signal strength. In CBR-Mobile protocol, cluster based routing collaborates with hybrid MAC protocol to support mobility of sensor nodes. Schedule timeslots are used to send the data message while the contention timeslots are used to send join registration messages. The performance of proposed CBR-Mobile protocol is evaluated using MATLAB and was observed that the proposed protocol improves the packet delivery ratio, energy consumption, delay and fairness in mobility environment compared to LEACH-Mobile and AODV protocols.     

Fuzzy Logic Based Distance and Energy-Aware Routing Protocol in Delay-Tolerant Mobile Sensor Networks

In challenged networks such as Wireless Sensor Networks, limitations such as nodes mobility, short radio range and sparse network density can prevent communications among nodes. Consequently, it can result in long delays in exchanging messages among nodes. Designing Delay-Tolerant Networks is considered to be an approach for dealing with lengthy breakdown of communication between nodes. Using multi-replica methods seems rational for these networks. However, a majority of these methods inject a large amount of replications of a message in the network so as to enhance message delivery probability which consequently leads to the loss of energy and reduction of network efficiency. Two major issues should be considered to achieve data delivery in such challenging networking environments: a routing strategy for the network and a buffer management policy. This study proposes a new routing protocol called Fuzzy-Logic based Distance and Energy Aware Routing protocol (FLDEAR) in delay tolerant mobile sensor network. A FLDEAR is a distance and energy aware protocol that reduces the number of message replications and uses two fuzzy inference systems in routing and buffer management. The results of conducted simulations indicated that this routing algorithm can be used for enhancing data packet delivery ratios and reducing data transmission overhead than several current Delay-Tolerant Mobile Sensor Networks routing protocols.     

A data transmission protocol for reliable and energy-efficient data transmission in a wireless sensor-actuator network

In a wireless sensor-actuator network, sensor nodes gather information on the physical world and can deliver messages with sensed values to only nearby nodes due to weak radio. Thus, messages sent by nodes might be lost due to not only collision but also noise. Messages are forwarded by sensor nodes to an actuator node. In the redundant data transmission (RT) protocol, a sensor node sends a message with not only its sensed value but also sensed values received from other sensor nodes. Even if a message with a sensed value v is lost, an actuator node can receive the value v from a message sent by another sensor node. In addition, we have to reduce the energy consumption of a sensor node. A sensor node mainly consumes the energy to send and receive messages. Even if an event occurs, only some number of sensor nodes sensing the event send the sensed values to reduce the total energy consumption. We discuss an energy-efficient data transmission protocol. We evaluate the RT protocol compared with the CSMA protocol in terms of how much sensing data a node can receive in presence of messages loss. We evaluate the RT protocol in terms of how many number of sensed values an actuator node can receive in presence of message loss. We show that about 72% of sensed values can be delivered to an actuator node even if 95% of messages are lost due to noise and collision.     

Distributed Group Management in Sensor Networks: Algorithms and Applications to Localization and Tracking

The tradeoff between performance and scalability is a fundamental issue in distributed sensor networks. In this paper, we propose a novel scheme to efficiently organize and utilize network resources for target localization. Motivated by the essential role of geographic proximity in sensing, sensors are organized into geographically local collaborative groups. In a target tracking context, we present a dynamic group management method to initiate and maintain multiple tracks in a distributed manner. Collaborative groups are formed, each responsible for tracking a single target. The sensor nodes within a group coordinate their behavior using geographically-limited message passing. Mechanisms such as these for managing local collaborations are essential building blocks for scalable sensor network applications.     

Networked sensor management and data rate control for tracking maneuvering targets

This paper presents sensor and data rate control algorithms for tracking maneuvering targets. The manuevering target is modeled as a jump Markov linear system. We present novel extensions of the Interacting Multiple Model (IMM), Particle filter tracker, and Probabilistic Data Association (PDA) algorithms to handle sensor and data rate control. Numerical studies illustrate the performance of these sensor and data rate control algorithms.     

A Diversity-based Selfish Node Detection Algorithm for Socially Aware Networking

Because mobile devices only have the limited resource in socially aware networking, some network nodes are unwilling to sacrifice their resource to forward messages to others for free, thus forming selfish nodes. However selfish nodes will cause dropping in the message delivery rate and affect the network performance, so this paper has proposed a diversity-based selfish node detection algorithm (DSNDA). Firstly, it mainly applies the node forwarding willingness mechanism to detect whether the node is selfish. If the node has the inadequate resource, that is, it cannot forward any messages for others; then it will be selfish. If the node’s resource is enough and the node has forwarded messages to other nodes, it indicates that the node is not selfish. Otherwise, DSNDA algorithm will use reputation mechanism to check the node further. If the node has broken faith, it indicates that the node is selfish. On the contrary the message confirmation mechanism will be employed to make the final check on the node. If a message does not be received or discarded after the node’s receiving it, which proves that it has selfish behaviour. If not, the node is normal. It can be proved by the simulation experiment and results that the DSNDA algorithm has significantly improved the delivery rate of messages, comparing with other algorithms. At the same time, reducing the network delay, thus verifying the feasibility of DSNDA.

     

视野有限的传感器网络中分布式多目标跟踪

在传感器网络的多目标跟踪研究中,大多数现有的跟踪算法通常设定网络中所有节点具有相同的视野,即所有节点都能够得到目标的测量,但在实际中,节点的感测范围通常是有限的。针对这一问题,本文提出了一种能够在感测范围有限的多传感器网络中实现多目标跟踪的分布式概率假设密度滤波算法,该算法通过融合传感器网络视野范围内的后验概率假设密度粒子集来克服传感器节点感测范围的局限。仿真结果表明,提出的算法可以在感测范围有限的情况下实现多目标状态和数目的有效跟踪,同时可以在一定程度上抑制杂波,具有较好的跟踪稳定性。      

Social group detection based routing in Delay Tolerant Networks

When implementing Mobile Ad Hoc Networks, a key characteristic of the network is the mobility pattern of the nodes. Based on the application, nodes can follow semi-predictable patterns, such as the routes followed by Vehicular Ad Hoc Networks, or the more strict schedules followed by aerial reconnaissance. Optimal routing schemes tend to take advantage of information regarding these patterns. In social environments, such as wildlife tracking or sending messages between humans, the devices and/or users will follow regular contact habits, tending to encounter social groups in which they participate. By identifying these groups, the patterns are used to optimize routing through a social environment. Dynamic Social Grouping (DSG), used to route messages strictly from a node to a basestation, is ideal for gathering sensor data and updating a shared data cache. In contrast, Dynamic Social Grouping-Node to Node (DSG-N²) is used to route messages between nodes, generally conventional communications. Both of these algorithms can be implemented ad null, meaning the devices initially have no information about their environment, and they work to reduce bandwith and delivery time while maintaining a high delivery ratio. In addition to presenting these two routing schemas, this article compares and contrasts two methods for estimating nodes’ delivery probabilities. The Contact Based Probability is based on encounters with other nodes, and the Performance Based Probability is based on the behavior of previous messages. The probability estimates were then validated with the Oracle analysis, which is based on knowledge of future events. This analysis indicated that DSG-N² probability estimates are comparable to the ideal.     

A probabilistic routing algorithm based on node communication capability and message strength

In delay-tolerant networks (DTN), node connection time and message transmission time are two important influencing factors that can improve the delivery rate. In this paper, we first define a new concept called communication capability (CC) and then apply this concept to the delivery predictability formulation in Prophet and improve it. Then, in Prophet, the selection of relay nodes relies only on the delivery predictability and ignores the caching and forwarding capability of the node. Therefore, we combine delivery predictability, buffering, and forwarding capability to develop a new adaptive relay node selection strategy. Subsequently, we define two metrics called message priority (MP) and message strength (MS). The node forwards messages sequentially based on message priority and discards messages based on message strength. Finally, we present a probabilistic routing algorithm based on node communication capability and message strength (CAMS). The simulation results show that compared with traditional routing algorithms, the CAMS can effectively improve the message delivery rate, reduce the overhead ratio, and keep average hop counts low.     

Extension of Delay Tolerant Network’s Routing Protocols for Preventing Excessive Utilization of Resources

The routing algorithms of DTN have the inbuilt storage management scheme such as Hop based TTL (Spray and Wait) or passive cure (Potential-based Entropy Adaptive Routing PEAR). There has been a significant amount of work in the past regarding buffer management policies. In this paper, we have proposed a new message deletion policy for multi-copy routing schemes. In this scheme, message delivery information is communicated to the other nodes in the network for removing useless bundles from the network, which prevents the nodes from the buffer overflow problem and avoid transfer of useless message replicas thus relaxing the resources of the nodes. We evaluate our proposed method by simulating network, on four major DTNs routing algorithms: Epidemic, Spray and Wait, ProPHET and MaxProp. The simulation results clearly show significant improvement in the value of delivery probability and the overhead ratio for an Epidemic, Spray and Wait, and Prophet routing protocols.     

基于连接质量和节点相关度的机会网络路由

提出利用连接质量估计节点间消息成功转发的概率,并证明了节点间相关度越高,消息转发率越高。在此基础上,提出基于连接质量和节点相关度的机会网络路由机制。路由计算节点转发效用值时,综合了连接质量和节点相关度;消息转发时,不断向相对于目的节点转发效用值高的节点转发消息。仿真结果表明,与传统路由相比,在消息送达率相同的前提下,该路由消息延迟更小、消耗的总能量更少。     

Message Drop Control Buffer Management Policy for DTN Routing Protocols

In delay tolerant network interruptions will occur continuously because there is no end-to-end path exists for the longer period of time from source to destination. In this context, delays can be immensely large due to its environment contrails e.g. wildlife tracking, sensor network, deep space and ocean networks. Furthermore, larger replication of messages put into the network is to increase delivery probability. Due to this high buffer occupancy storage space and replication result in a huge overhead on the network. Consequently, well-ordered intelligent message control buffer drop policies are necessary to operate on buffer that allows control on messages drop when the node buffers are near to overflow. In this paper, we propose an efficient buffer management policy which is called message drop control source relay (MDC-SR) for delay tolerant routing protocols. We also illustrate that conventional buffer management policy like Drop oldest, LIFO and MOFO be ineffective to consider all appropriate information in this framework. The proposed MDC-SR buffer policy controls the message drop while at the same time maximizes the delivery probability and buffer time average and reduces the message relay, drop and hop count in the reasonable amount. Using simulations support on an imitation mobility models Shortest Path Map Based Movement and Map Route Movements, we show that our drop buffer management MDC-SR with random message sizes performs better as compared to existing MOFO, LIFO and DOA.     

A Tracking-Based Target Locating Algorithm in Wireless Sensor Networks

1　IntroductionAwirelesssensornetworkisusuallycomposedofhundredsorthousandsofsensorsequippedwithcomputation ,sensingandcommunicationdevices,whicharecoordinatedinadistributedmodeinordertomonitoracertaingeographicalregionandcollectinformationontheirsurroundings[1 ] .Thecollecteddataisthenusedtoanswervariousqueries.RecentadvancesinMEMS ,wirelesscommunications,anddigitalelectronicshavemadepossiblethecheapandfastdeploymentofsensornetworks[2 ] .Suchadhoc,self organizingsensornetworksarereceivingin…