DAI based wireless sensor network for multimedia applications

In Wireless Multimedia Sensor Network (WMSN), the time critical and delay sensitive applications like video, audio, image demands high bandwidth and transmission resources. The provision of Cognitive Radio (CR) can effectively utilize the available spectrum in the most appropriate way to provide high bandwidth in the Wireless Sensor Network (WSN) environment as Cognitive Radio sensor network (CRSN). The CR features are applicable in WMSN paradigm with required changes in transmission parameter for bandwidth hungry multimedia applications. In this paper, we propose an approach for setting up a cost-efficient and higher data rates communication in Wireless Multimedia Cognitive Radio Sensor Network (WMCRSN). The process analyses power allocation for sensor nodes by dynamic channel modelling and allocates power using multi-agent based Distributed Artificial Intelligence (DAI) in WMCRSN applications. The novelty in the approach lies in analyzing the real-time spectrum sensing outputs system for high data rate wireless multimedia applications. The DAI makes the process of power allocation in a smart way for having low latency based intra and inter cluster communication between sensor nodes. The performance parameters of the network, i.e. probability of detection and false alarm with the modelled error rates are presented. The mathematical analysis and simulation results justifies the feasibility and merits of the proposed method over conventional methods.

     

能量有效的无线传感器网络协同覆盖

在节点随机分布的无线传感器网络目标覆盖中,考虑到单个节点有时难以完成对目标的感知,利用节点的概率感知模型和漏检率的概念,提出了节点协同覆盖的思想,并建立了协同覆盖模型;详细分析并推导了协同覆盖感知概率、节点数目和节点参与协同覆盖的最低感知概率之间的关系;在协同覆盖模型的基础上,考虑节点能量消耗的因素,设计了优化网络使用寿命的协同覆盖算法ECTC;仿真结果表明,该算法在改善网络感知概率的同时,延长了网络的使用寿命。     

基于APIT的三维移动代理路由算法研究*

针对现有的移动代理路由算法都是基于二维环境的不足,提出了一种能应用于三维环境中的移动代理路由算法。首先,使用APIT定位法来获取三维空间中的传感器坐标;在获取传感器节点坐标后,引入蚁群算法对移动代理访问传感器节点的路径进行优化,由此,得到了一种全新的基于APIT的三维移动代理路由算法。仿真实验表明,新移动代理路由算法能较好地适应无线传感器网络的实际应用环境,且路径优化效果明显。     

认知车载网中基于TDMA/CSMA的混合多信道MAC协议研究

在传统车载自组网(Vehicular Ad Hoc Network, VANET)中采用认知无线电(Cognitive Radio, CR)技术可以解决无线电频谱资源短缺的问题,该技术形成了新兴的认知车载网络(CR-VANET),其关键技术之一是设计高效可靠的介质访问控制(Medium Access Control, MAC)协议。MAC协议在很大程度上影响着车载移动环境的吞吐量,丢包率和传输时延等性能,基于认知车载网中MAC协议的要求,提出了一种TDMA与CSMA相结合的多信道MAC协议(CRTC-MAC)。在固定时隙分配时采用基于无竞争的TDMA访问策略,在动态时隙分配时采用基于竞争的CSMA接入方案,并在此基础之上对传统的TDMA和CSMA访问方式进行了改进。性能分析和仿真结果表明,所提出的MAC协议能有效降低节点间数据包传输时所产生的碰撞,改善网络性能。     

无线传感器网络中覆盖控制技术综述

覆盖控制是无线传感器网络应用的一个基本问题,反映了网络所能提供的"感知"服务质量,可以使无线传感器网络的空间资源得到优化分配,进而更好地完成环境感知、信息获取和有效传输的任务;立足于无线传感器网络的覆盖控制问题,分析了网络覆盖技术在国内外研究的现状与发展,指出了传感器网络覆盖算法中需要解决的问题,并提出了将多目标进化算法与智能计算技术用于动态覆盖控制技术研究设想。     

基于优化策略的混合定位算法

针对无线传感器网络(Wireless sensor network, WSN)的应用需求提出一种基于优化策略的混合节点定位算法. 选择1-hop节点最多的点作为初始点, 利用多维标度(Multi-dimensional scaling, MDS)方法计算初始节点及其1-hop节点的相对坐标, 并将这些节点的坐标发送给周围未定位节点; 未定位的节点根据接收到的坐标与节点间的距离, 利用极大似然法估算自身的坐标; 最后通过坐标变换计算所有节点的绝对坐标. 在此基础上, 进一步提出将本文节点定位算法与集中式和分布式优化策略相结合来优化网络节点的估计坐标, 以提高节点定位精度. 仿真结果表明本文提出的算法是有效的, 能够较好地完成无线传感器网络节点的定位.     

基于协作传输的大范围WSNs能耗均衡分簇算法

由于大范围无线传感器网络（WSNs）节点的数量巨大,网络的能量消耗极不均,提出一种基于协作传输的分簇算法—EBBMCC—LS算法。该算法在保证网络均匀分簇的前提下,能保证网络中簇头节点的均匀分布,在簇间通信时加入协作传输策略,传感器节点之间通过协作传输构成虚拟多天线系统,改善系统性能,解决了大范围WSNs中的能耗不均现象。实验验证：该算法能够均衡大范围WSNs中的能耗,延长网络寿命,可促进大范围WSNs应用的推广。     

无线传感器网络中多Sink节点位置部署研究

通过对随机分布的无线传感器网络节点密度和能量消耗的关系的分析,提出了无线传感器网络中多异构节点位置部署的区域密度优先(RDF)算法。此算法采用密度优先原则来决定Sink节点的放置位置,通过栅格和异构节点通信范围对网络进行区域划分。该算法比递归算法的异构节点放置位置优越,虽然在网络寿命上相接近,但远大于随机分布策略的寿命,且RDF更适合实际应用。通过仿真验证:该算法能够有效延长网络寿命和快速实现部署。     

An efficient range-free localization algorithm for wireless sensor networks

Node positioning is a fundamental problem in applications of wireless sensor networks (WSNs). In this paper, a new range-free algorithm, called spring swarm localization algorithm (SSLA), is proposed for positioning WSNs. To determine the locations of sensor nodes, the proposed algorithm uses network topology information and a small fraction of sensor nodes which know their locations. Numerical simulations show that high positioning accuracy can be obtained by using the algorithm. Some examples are given to...     

Clustering synchronisation of wireless sensor network based on intersection schedules

Wireless sensor network (WSN) technology has gained in importance due to its potential support for a wide range of applications. Most of the WSN applications consist of a large number of distributed nodes that work together to achieve common objectives. Running a large number of nodes requires an efficient mechanism to bring them all together in order to form a multi-hop wireless network that can accomplish specific tasks. Even with the recent developments made in WSN technology, a number of important challenges still create vulnerabilities for WSNs, including: energy waste sources; synchronisation leaks; low network capacity; and self-configuration difficulties. However, energy efficiency perhaps remains both the most challenging and highest priority problem due to the scarce energy resources available in sensor nodes. Synchronization by means of scheduling clusters allows the nodes to cooperate and transmit traffic in a scheduled manner under the duty cycle mechanism. This paper aims to make further advances in this area of work by achieving higher accuracy and precision in time synchronisation through controlling the network topology, self-configuration and estimation of the clock errors between the nodes and finally correcting the nodes’ clock to the estimated value. Furthermore, the target in designing energy efficient protocol relies on synchronized duty cycle mechanism and requires a precise synchronisation algorithm that can schedule a group of nodes to cooperate by communicating together in a scheduled manner. These techniques are considered as parameters in the proposed OLS-MAC algorithm. This algorithm has been designed with the objective of ensuring the schedules of the clusters overlap by introducing a small shift in time between the adjacent clusters’ schedules to compensate for the clock drift. The OLS-MAC algorithm is simulated in NS-2 and compared to some S-MAC derived protocols. The simulation results verified that the proposed algorithm outperforms previous protocols in number of performance criterion.     

无线传感器网络节点调度优化分簇算法研究*

节点调度优化分族算法根据网络节点部署的特点,在不影响网络服务质量的情况下,通过冗余节点调度优化分族的方法能有效减少网络中工作节点的数量,从而节约网络平均每一轮的网络能耗.仿真结果表明,与未考虑冗余节点状态调度的算法相比,节点调度优化分簇算法有效提高了网络能量利用率,延长了网络寿命.     

A learning automata-based algorithm for solving coverage problem in directional sensor networks

Wireless sensor networks have been used in a wide variety of applications. Recently, networks consisting of directional sensors have gained prominence. An important challenge facing directional sensor networks (DSNs) is maximizing the network lifetime while covering all the targets in an area. One effective method for saving the sensors’ energy and extending the network lifetime is to partition the DSN into several covers, each of which can cover all targets, and then to activate these covers successively. This paper first proposes a fully distributed algorithm based on irregular cellular learning automata to find a near-optimal solution for selecting each sensor’s appropriate working direction. Then, to find a near-optimal solution that can cover all targets with the minimum number of active sensors, a centralized approximation algorithm is proposed based on distributed learning automata. This algorithm takes advantage of learning automata (LA) to determine the sensors that must be activated at each stage. As the presented algorithm proceeds, the activation process is focused on the sensor nodes that constitute the cover set with the minimum number of active sensors. Through simulations, we indicate that the scheduling algorithm based on LA has better performance than the greedy algorithm-based scheme in terms of maximizing network lifetime.     

MidFusion: An adaptive middleware for information fusion in sensor network applications

Applications and services are increasingly dependent on networks of smart sensors embedded in the environment to constantly sense and react to events. In a typical sensor network application, information is collected from a large number of distributed and heterogeneous sensor nodes. Information fusion in such applications is a challenging research issue due to the dynamicity, heterogeneity, and resource limitations of sensor networks. We present MidFusion, an adaptive middleware architecture to facilitate information fusion in sensor network applications. MidFusion discovers and selects the best set of sensors or sensor agents on behalf of applications (transparently), depending on the quality of service (QoS) guarantees and the cost of information acquisition. We also provide the theoretical foundation for MidFusion to select the best set of sensors using the principles of Bayesian and Decision theories. A sensor selection algorithm (SSA) for selecting the best set of sensors is presented in this paper. Our theoretical findings are validated through simulation of the SSA algorithm on an example scenario.     

抵御虫洞攻击的无线传感器网安全定位算法

节点定位技术是无线传感器网络的支撑技术之一,节点位置信息是很多基于无线传感器网络的应用的基础.无线传感器网络是一个动态的网络,每隔一段时间需要进行重新定位,并且在重定位过程中易受到攻击节点攻击.针对无线传感器网络中无需测距的定位技术,分析虫洞攻击对DV-Hop定位的影响,提出了一种基于信誉模型的抵御虫洞攻击的分布式轻量级DV-Hop安全定位算法TMDV-Hop(Trust-Model-based DV-Hop Localization Against Wormhole Attack).仿真表明,在无需额外硬件辅助下,TMDV-Hop算法能有效降低虫洞攻击对定位过程的影响,验证了该算法的有效性.     

基于移动锚节点无线传感器网络定位的算法

无线传感器网络应用在很多场合中,监测目标进行定位和跟踪是最基本的应用。在无线传感器网络中基于移动锚节点的定位算法进行设计仿真,网络部署成本显著减少。节点能耗减少,运行时间延长,而且在网络边缘上的节点100％都能获得节点位置．该设计算法能得到完整的网络信息,即使在网络节点出现故障后,通过移动锚节点来重新确认所有无故障节点的位置,进行重新定位。     

一种基于时间延迟机制的无线传感器网络分簇算法

为了延长网络的生存时间,需要设计能量有效的路由协议以适应传感器网络的特点.成簇算法是传感器网络中减少能量消耗的一种关键技术,它能够提高网络的生存时间.本文提出一种基于时间延迟机制的分簇算法,称为CHTD.该算法建立了节点的时间延迟机制模型,使得能量较多的节点能够在每一轮中被优先选为簇首.同时,通过维持每个节点的簇首信息集合使得每轮产生的簇首数目稳定且位置均匀分布.模拟实验表明,CHTD有效地均衡了网络中节点的能量消耗,并显著地延长了网络的存活时间.     

三维水下监视传感器网络的拓扑生成算法

当前大多数传感器网络研究假设传感器节点在二维平面部署,然而许多水下传感器网络应用要求节点在三维空间分布。针对三维水下监视应用,提出一种新颖的分布式传感器网络拓扑生成算法（ETG）。基于格理论,ETG算法将节点的移动控制与活动设备的调度相结合。初始时刻监视设备密集部署在二维海平面上,ETG算法根据局部信息选择活动设备,并通过控制其传感器节点在垂直方向的移动,形成一个三维水下网络。仿真实验表明,ETG算法能够以较小的平均节点移动距离覆盖较大的空间,从而有效减少网络建立阶段的能量开销。     

Hotspot Preventing Routing algorithm for delay-sensitive applications of in vivo biomedical sensor networks

Networks of implanted biomedical sensor nodes promise to give a new direction to medical research. The in vivo sensor nodes collect desired biometric data and communicate the data wirelessly to a base-station through a multi-hop network. The wireless communication produces heat, leading to a rise in the temperature of the nodes. A high temperature of the in vivo nodes for a prolonged period is not desired as it might damage the surrounding tissues. Medical applications are also often delay-sensitive. In this paper, we propose Hotspot Preventing Routing (HPR) algorithm that performs much better than the shortest hop routing algorithm and the previously proposed Thermal Aware Routing Algorithm (TARA) in terms of preventing the formation of hotspots and reducing the average packet delivery delay by dynamically adapting to the network load. The simulation results presented also show that the HPR algorithm is highly scalable, increases the operational life of the network and helps reduce the number of packets dropped.     

无线传感器网络一种不相交路径路由算法

无线传感器网络经常被用来采集物理数据,监测环境变化.由于低功耗无线通信不确定性、链路质量不稳定性以及节点失效等问题,传感器网络很容易导致路由数据包丢失.为了提高网络路由的可靠性,人们提出多路径路由算法.多路径路由中源节点到目的节点的多条路径可能含有公共节点,或者公共边,如果公共节点或者公共链路失效,则这个数据包也丢失,因此又有人提出不相交多路径路由算法.不相交多路径路由算法又分为链路不相交多路径路由算法和节点不相交多路径路由算法.提出了一种不相交路径路由算法,可以将感知节点采集到的数据通过不相交路径传送到汇聚节点,提高路由的可靠性.而且,这个算法还可以很方便地应用到多Sink节点的网络当中.该路由算法用到的路由表大小为|K|,其中|K|表示路径数.算法的运行时间复杂度是O(|L|),其中|L|表示网络中的边数.     

面向交通信息采集的智能无线传感器节点

为了准确实时获取交通信息参量,利用无线传感器网络技术作为智能交通感知前端和通信手段,融合GPRS技术,构建交通信息采集网,为道路交通信息采集提供了更加便捷的解决方案。设计了交通信息采集的传感器节点,提出了动态车辆探测算法和车速测量算法。实测结果表明:动态车辆探测算法和车速测量算法能够在计算能力有限的传感器节点上实现,能准确实时地获得车流量、车速等交通参量;该交通信息采集系统能满足网络大规模部署的需求,可应用于智能交通系统。