无线传感器/反应器网络中反应节点优化重定位机制研究

针对无线传感器/反应器网络中因多个反应器失效而造成的反应器网络连通性被破坏问题,以网络流理论为基础,提出了一个基于网络流的多目标规划模型来求解优化的反应器重定位方案。模型将反应器网络看成是一个运输网络,通过流平衡条件来重建反应器网络的连通性。最小化多个参与恢复的反应器总体开销和最小化单个反应器的最大开销是该模型的两个优化目标。仿真实验结果表明,基于该模型的优化重定位方案能够有效地恢复因多反应器节点失效而造成的网络连通性问题。     

无线传感网中能量有效的多sink重定位算法

在无线传感器网络中只部署一个静止不动的sink节点会带来诸多弊端,如网络能耗不均衡、生存期短、丢包率大等。为解决上述问题,提出一种新的且容易操作的多sink重定位算法EEMSR,即在整个网络生存期的时间内,多个sink节点能以逐步逼近和协作的方式移动至各自的最优位置。经仿真验证,该算法能极大提升网络生存期和数据包交付率等网络性能。     

Maximizing lifetime of event-unobservable wireless sensor networks

In wireless sensor networks (WSNs) contextual information such as the information regarding whether, when, and where the data is collected cannot be protected using only traditional measures (e.g., encryption). Contextual information can be protected against global eavesdroppers by periodic packet transmission combined with dummy traffic filtering at proxy nodes. In this paper, through a Linear Programming (LP) framework, we analyze lifetime limits of WSNs preserving event-unobservability with different proxy assignment methodologies. We show that to maximize the network lifetime data flow should pass through multiple proxies that are organized as a general directed graph rather than as a tree.     

带执行器节点的无线传感器网络的分簇算法

带执行器节点的无线传感器网络(WSAN)是指在无线传感器网络中加入执行器,传感器用于检测物理环境信息,执行器收集和处理这些检测数据,并作出适当的执行任务。传感器和执行器的协作是WSAN研究的一个重要内容,就此提出了一个动态分簇算法,根据事件发生的实际情况,仅仅对该事件区域分簇,每个簇包括一个执行器节点以及传送数据到该执行器节点的传感器节点。通过这种分簇,可以决定传感器与哪个执行器通信以及路由方式。     

无线传感执行网络的协调机制研究*

主要研究了无线传感执行网络中执行节点之间的协调,提出了基于单执行节点任务的分布式协调机制。在多执行节点协调算法中,建立了多执行节点协调的数学模型,引入基于进化算法的多目标优化,提高了系统的最优性能。     

A cooperative pursuit-evasion game in wireless sensor and actor networks

This paper studies the problem of the pursuit-evasion game under the wireless sensor and actor networks (WSANs). In order to plan paths for pursuers to capture an evader in the pursuit-evasion game, a novel multi-step cooperative strategy is presented. Under this strategy, the pursuit-evasion game is studied in two stages. In the first stage we assume that the evader is always static in the workplace, and in the second stage the evader will move once it senses the existence of pursuers. A Daisy-Chain Formation algorithm and a sliding mode-based method are presented to control the pursuit. Based on Lyapunov stability theory, the proposed algorithm is proved to be convergent. At last, simulation results are provided to demonstrate the effectiveness of the proposed method.     

Maximizing lifetime in wireless sensor networks with multiple sensor families

Wireless sensor networks are generally composed of a large number of hardware devices of the same type, deployed over a region of interest in order to perform a monitoring activity on a set of target points. Nowadays, several different types of sensor devices exist, which are able to monitor different aspects of the region of interest (including sound, vibrations, proximity, chemical contaminants, among others) and may be deployed together in a heterogeneous network. In this work, we face the problem of maximizing the amount of time during which such a network can remain operational, while maintaining at all times a minimum coverage guarantee for all the different sensor types. Some global regularity conditions in order to guarantee a fair level of coverage for each sensor type to each target are also taken into account in a second variant of the proposed problem. For both problem variants we developed an exact approach, which is based on a column generation algorithm whose subproblem is either solved heuristically by means of a genetic algorithm or optimally by an appropriate ILP formulation. In our computational tests the proposed genetic algorithm is shown to be able to dramatically speed up the procedure, enabling the resolution of large-scale instances within reasonable computational times.     

无线传感器网络栅栏覆盖改进

栅栏覆盖是无线传感器网络中的研究热点,鉴于移动节点的高昂造价以及在移动过程中的巨大能耗,针对高效节能的修复栅栏漏洞问题进行研究.建立静止节点的权重图,并利用迪杰斯特拉算法(Dijkstra)寻找所需最少数目的移动节点和构建栅栏覆盖的最短路径.根据构建栅栏覆盖的最短路径和基于路径上的每个栅栏漏洞所需的最少移动节点,将栅栏漏洞划分为简单情况和一般情况,借助于最大权匹配算法(Kuhn-Munkres)求解移动节点的最短移动距离.仿真实验表明,所提出算法明显减少了移动节点的移动距离,实现了栅栏覆盖.     

Connectivity and coverage maintenance in wireless sensor networks

One of the main design challenges for wireless sensor networks (WSNs) is to obtain long system lifetime without sacrificing system original performance such as communication connectivity and sensing coverage. A large number of sensor nodes are deployed in redundant fashion in dense sensor networks, which lead to higher energy consumption. We propose a distributed framework for energy efficient connectivity and coverage maintenance in WSNs. In our framework, each sensor makes self-scheduling to separately control the states of RF and sensing unit based on dynamic coordinated reconstruction mechanism. A novel energy-balanced distributed connected dominating set algorithm is presented to make connectivity maintenance; and also a distributed node sensing scheduling is brought forward to maintain the network coverage according to the surveillance requirements. We implemented our framework by C++ programming, and the simulation results show that our framework outperforms several related work by considerably improving the energy performance of sensor networks to effectively extend network lifetime.     

无线传感器网络分布式连通算法

针对离散目标覆盖集的连通问题,设计了一种分布式构造连通集的算法,这种算法并不要求网络的全局信息,仅仅依赖每个节点的3跳内的邻居信息;对于大规模密集型的无线传感器网络,这种分布式算法更适合无线传感器网络的实际应用。     

Clustering of wireless sensor and actor networks based on sensor distribution and connectivity

Wireless Sensor and Actor Networks (WSANs) employ significantly more capable actor nodes that can collect data from sensors and perform application specific actions. To take these actions collaboratively at any spot in the monitored regions, maximal actor coverage along with inter-actor connectivity is desirable. In this paper, we propose a distributed actor positioning and clustering algorithm which employs actors as cluster-heads and places them in such a way that the coverage of actors is maximized and the data gathering and acting times are minimized. Such placement of actors is done by determining the k-hop Independent Dominating Set (IDS) of the underlying sensor network. Basically, before the actors are placed, the sensors pick the cluster-heads based on IDS. The actors are then placed at the locations of such cluster-heads. We further derive conditions to guarantee inter-actor connectivity after the clustering is performed. If inter-connectivity does not exist, the actors coordinate through the underlying sensors in their clusters to adjust their locations so that connectivity can be established. The performances of the proposed approaches are validated through simulations.     

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。     

基于激素调节的传感器网络覆盖算法*

人体内环境的平衡是由各种激素的相互作用来协同调节和控制的,根据抽象出的激素作用机理,提出了一种基于激素调节的传感器网络覆盖算法(HCA),该算法是完全分布式的,节能的传感器网络覆盖算法,算法中节点状态(sleep或active)的选择通过激素来调节和控制,即通过给邻居节点发送激活荷尔蒙或抑制荷尔蒙来刺激或抑制邻居节点成为active状态。仿真实验表明,与DELIC和UC算法相比,该算法既能有效地保证区域覆盖,又可以使得active状态的节点尽可能少。     

Localized motion-based connectivity restoration algorithms for wireless sensor and actor networks

In wireless sensor and actor networks maintaining inter-actor connectivity is very important in mission-critical applications where actors have to quickly plan optimal coordinated response to detected events. Failure of one or multiple actors may partition the inter-actor network into disjoint segments, and thus hinders the network operation. Autonomous detection and rapid recovery procedures are highly desirable in such a case. This paper presents DCR, a novel distributed partitioning detection and connectivity restoration algorithm to tolerate the failure of actors. DCR proactively identifies actors that are critical to the network connectivity based on local topological information, and designates appropriate, preferably non-critical, backup nodes. Upon failure detection, the backup actor initiates a recovery process that may involve coordinated relocation of multiple actors. We also present an extended version of DCR, named RAM, to handle one possible case of a multi-actor failure. The proposed algorithms strive to avoid procrastination, localize the scope of recovery and minimize the movement overhead. Simulation results validate the performance of the proposed algorithms.     

Maximizing network lifetime in wireless sensor networks with regular topologies

Limited energy supply (battery-powered) is a crucial problem in wireless sensor networks (WSNs). Sensor node placement schemes and routing protocols are mostly proposed to address this problem. In this paper, we first present how to place sensor nodes by use of a minimal number of them to maximize the coverage area when the communication radius of the sensor node is different from the sensing radius, which results in the application of regular topology to WSNs deployment. With nodes placed at an equal distance and equipped with an equal power supply, the problem of unbalanced energy consumption in 2-D regular topologies becomes more severe and much more difficult to tackle than that in 1-D chains, though the latter is known as an already quite hard problem. We address this problem and propose an adaptive data collection scheme by employing different communication radii for nodes in different locations to balance the energy consumption in WSNs. In order to achieve the ultimate goal of maximizing network lifetime in grid-based WSNs, we give a mathematical formulation, which shows the problem of maximizing network lifetime is a nonlinear programming problem and NP-hard even in the 1-D case. We discuss several heuristic solutions and show that the halving shift data collection scheme is the best solution among them. We also generalize the maximizing network lifetime problem to the randomly-deployed WSNs, which shows the significance of our mathematical formulation for this crucial problem in WSNs.     

一种连通性覆盖的无线传感器网络节点调度算法

研究传感器节点随机部署于监测区域内,无节点地理位置信息情况下,如何能量有效地保证网络的通信连通与感知覆盖;节点采用基于概率的联合感知模型。提出CDS-based SSCA算法,其为一种基于连通支配集构造树的节点调度机制,每个节点根据剩余能量和与父节点的距离来设置等待时间及成为候选节点优先级。模拟实验结果显示,本算法能够能量有效地满足感知覆盖和连通覆盖要求;与ASW算法相比较,工作节点个数较少,网络生命周期明显延长,降低了网络整体耗能。     

一种新型无线传感器网络节能覆盖方案

针对一种实际地理环境下的生态监测问题,把拓扑控制中的功率控制思想引入到节能覆盖的研究中,建立感知半径之和最小的数学模型,并用遗传算法求解该模型,得到最优覆盖解。最后,对该方案进行能耗分析和仿真实验,结果表明该算法不仅节能,而且可以获得较高覆盖率,降低信道通讯干扰并提高网络的抗毁性。     

无线传感器网络节点自调度冗余覆盖算法

对于能量受限的无线传感器网络,延长网络存活的时间很关键。针对这个问题,提出了一种基于能量均衡的传感器节点自调度冗余覆盖协议（SRCP）,通过仿真实验对该算法的有关性能进行了评价,性能评价表明：这种算法能有效使用节点能力,延长网络存活时间。     

无线传感器网络覆盖问题的研究进展*

分析了无线传感器网络的网络特征以及影响网络覆盖的重要因素,总结和评估了近年来提出的覆盖机制,同时对该领域尚存问题以及发展趋势进行了讨论。