基于点的POMDPs在线值迭代算法

部分可观察马尔可夫决策过程(partially observable Markov decision processes,简称POMDPs)是动态不确定环境下序贯决策的理想模型,但是现有离线算法陷入信念状态“维数灾”和“历史灾”问题,而现有在线算法无法同时满足低误差与高实时性的要求,造成理想的POMDPs模型无法在实际工程中得到应用.对此,提出一种基于点的POMDPs在线值迭代算法(point-based online value iteration,简称PBOVI).该算法在给定的可达信念状态点上进行更新操作,避免对整个信念状态空间单纯体进行求解,加速问题求解;采用分支界限裁剪方法对信念状态与或树进行在线裁剪;提出信念状态结点重用思想,重用上一时刻已求解出的信念状态点,避免重复计算.实验结果表明,该算法具有较低误差率、较快收敛性,满足系统实时性的要求.     

无线传感器网络目标跟踪动态簇成员调度策略

通过分析目标跟踪无线传感器网络监测精度、节点能量消耗与簇成员唤醒/休眠之间的内在联系,针对网络节点能量有限、密集部署节点监测数据存在冗余、传感器节点的自身位置估计误差和目标监测估计误差等问题,引入部分可观察Markov决策过程(POMDP)理论,提出一种基于目标跟踪准确度和节点能量消耗加权回报率的动态簇成员调度模型;针对动态簇成员调度算法复杂度偏高的问题,采用基于信念点的值迭代在线策略求解算法,实现传感器簇成员节点协作策略的动态生成和在线调整。仿真结果表明:该算法能够提高目标跟踪准确性,降低节点能量消耗,延长网络生存时间。     

基于正六边形区域划分的无线传感器网络动态目标跟踪

针对无线传感器网络(WSNs)目标跟踪应用中的跟踪精度与能耗问题,提出一种能量均衡消耗的目标跟踪协同算法.该算法以正六边形网格作为分簇模型,能动态地唤醒无线传感器网络中合适的簇对目标状态进行估计.同时引入了虚拟簇头的概念用于优化簇头选举策略.仿真分析表明:所提出的算法与簇内集中式算法相比不仅具有相当的估计性能,并能有效降低对簇头节点的性能要求.除此之外,通过自适应动态簇头选举策略,有效地均衡了各簇中节点能量消耗,提高了系统的健壮性.     

改进人工蜂群算法在WSNs覆盖优化中的应用

为了改善无线传感器网络(WSNs)中节点分布不均匀、部署时间长、网络覆盖率低等缺点,提出了一种基于改进人工蜂群(ABC)算法的覆盖优化方法、通过引入覆盖因子改善观察蜂选择算子,结合反馈策略改进采蜜蜂搜索过程,采用基于当前最优值的自适应侦查策略,提高了算法的收敛速度与精度.仿真结果表明:方法通过较少的迭代次数达到传感器分布更加均匀,覆盖率更高的目的,有效减少了传感器节点冗余、降低了网络能耗,延长了WSNs的生命周期.     

基于Grid-VFACO的数字化车间WSNs路由算法

针对数字化车间中无线传感器网络(WSNs)对数据采集频率高,能量消耗快,提出了基于网格和虚拟力导向的蚁群优化(Grid-VFACO)高能效WSNs路由算法。该算法根据最优簇首数将数据采集区划分成网格,在网格中采用基于候选者的机制选择簇首,实现簇首均匀分布。在簇首形成的上层网络中,利用节点间的虚拟吸引力作为蚁群算法中转移概率规则启发因子,寻找最优数据转发路径。仿真实验结果表明:该算法能够有效减少网络能耗,保证数字化车间WSNs长时间稳定地工作。     

基于CPSO的无线传感器网络路由优化

研究无线传感器网络路由优化问题,由于无线传感器节点的能量受到限制,通信过程能量损耗,影响网络的性能。传统粒子群算法难以获得最优网络路由方案。为延长网络生存时间,结合粒子群的快速性和混沌的遍历性优点,提出了一种混沌粒子群(CPSO)的无线网络路由优化方法。通过粒子群算法的自组织、动态寻优能力,并通过混沌机制对粒子群进行混沌扰动,增加多样性,加快最优路由优化速度,使网络最优路由和能量消耗间尽量平衡。仿真结果表明,相对于传统优化算法,CPSO提高了无线传感器网络路由优化速度,减少网络能量消耗,有效延长了网络生存时间,为提高整个网络通信效率提供了参考。     

基于改进粒子滤波器的WSNs目标跟踪算法

提出了一种适用于无线传感器网络(WSNs)的目标跟踪算法,该算法基于改进型粒子滤波器(PF),根据当前的预测值优化PF的方向值,从而保证精确地预测到目标的移动方向;修改了目标突发变化引起的粒子滤波器预测误差,能够很好地跟踪目标移动过程中的异常、突发的移动变化.仿真结果表明:该目标跟踪算法采用新的粒子滤波器之后,可以获得...     

基于Monte Carlo 粒子滤波的POMDPs 在线算法

针对部分可观察马尔可夫决策过程(POMDPs)的信念状态空间是一个双指数规模问题,提出一种基于 Monte Carlo 粒子滤波的 POMDPs 在线算法.首先,分别采用粒子滤波和粒子映射更新和扩展信念状态,建立可达信念状态与或树;然后,采用分支界限裁剪方法对信念状态与或树进行裁剪,降低求解规模.实验结果表明,所提出算法具有较低的误差率和较快的收敛性,能够满足系统实时性的要求.     

一种基于遗传聚类的无线传感器网络分簇算法

针对无线传感器网络(WSNs)存在负载能量不平衡的问题,为实现传感器网络能耗均衡、最大化延长网络周期,提出一种基于遗传模糊聚类算法的WSNs分簇算法。在该算法中,用遗传算法(GA)优化模糊聚类算法,改进模糊聚类算法对初始值敏感的问题,形成节点位置的最优分簇。仿真结果表明:无论传感器节点如何分布,与FCM相比,该算法每次都收敛到最优目标函数值,每次分簇结果都相同,其分簇效果要优于FCM。     

基于群体智能和遗传算法的WSNs能耗优化关键技术研究

节点能耗是决定无线传感器网络(WSNs)生存期的重要参数,设计良好的网络通信协议可以很大程度上减少和平衡能量消耗。网络协议设计簇头和簇间路由的计算过程是多项式时间无法解答的NP问题,该文讨论了5种自然元启发算法,既4种群体智能算法和遗传算法应用于WSNs能耗优化的关键技术,给出了不同网络能量结构模型的簇间单跳和多跳场景的设计建议,旨在为搭建大规模WSNs网络提供参考和借鉴。     

WSN中一种目标追踪在线节点调度算法

针对目标追踪无线传感器网络节点能量有限、感知信息存在不确定性等问题,提出一种基于部分可观察马尔可夫决策过程的在线节点调度算法。通过状态转移函数和观察函数描述移动目标的不确定性,根据奖赏函数平衡追踪性能和节点能量消耗,并构造有限深度的可达信念与或树降低运算复杂度,实现调度策略在线求解。实验结果表明,该算法能平衡目标追踪质量与节点能量消耗,且满足实时性 要求。     

Novel sensor scheduling and energy-efficient quantization for tracking target in wireless sensor networks

This paper focuses on sensor scheduling and information quantization issues for target tracking in wireless sensor networks (WSNs). To reduce the energy consumption of WSNs, it is essential and effective to select the next tasking sensor and quantize the WSNs data. In existing works, sensor scheduling’ goals include maximizing tracking accuracy and minimizing energy cost. In this paper, the integration of sensor scheduling and quantization technology is used to balance the tradeoff between tracking accuracy and energy consumption. The main characteristic of the proposed schemes includes a novel filtering process of scheduling scheme, and a compressed quantized algorithm for extended Kalman filter (EKF). To make the algorithms more efficient, the proposed platform employs a method of decreasing the threshold of sampling intervals to reduce the execution time of all operations. A real tracking system platform for testing the novel sensor scheduling and the quantization scheme is developed. Energy consumption and tracking accuracy of the platform under different schemes are compared finally.     

基于改进蚁群优化算法的无线传感器网络路由研究

无线传感器网络为能量受限系统,为了促使网络节点能量消耗相对均衡,将蚁群优化(ACO)算法应用于无线传感器网络的路由选择,提出一种基于能量均衡的无线传感器网络路由算法。该算法将节点能量作为转移概率规则启发因子,通过计算转移概率和适应度值找到最优路径。仿真结果表明:该算法可以显著减低网络总能耗,从而延长无线传感器网络的生命周期。     

Energy-efficient adaptive sensor scheduling for target tracking in wireless sensor networks

Sensor scheduling is essential to collaborative target tracking in wireless sensor networks (WSNs). In the existing works for target tracking in WSNs, such as the information-driven sensor query (IDSQ), the tasking sensors are scheduled to maximize the information gain while minimizing the resource cost based on the uniform sampling intervals, ignoring the changing of the target dynamics and the specific desirable tracking goals. This paper proposes a novel energyefficient adaptive sensor scheduling approach that jointly selects tasking sensors and determines their associated sampling intervals according to the predicted tracking accuracy and tracking energy cost. At each time step, the sensors are scheduled in alternative tracking mode, namely, the fast tracking mode with smallest sampling interval or the tracking maintenance mode with larger sampling interval, according to a specified tracking error threshold. The approach employs an extended Kalman filter (EKF)-based estimation technique to predict the tracking accuracy and adopts an energy consumption model to predict the energy cost. Simulation results demonstrate that, compared to a non-adaptive sensor scheduling approach, the proposed approach can save energy cost significantly without degrading the tracking accuracy.     

基于博弈论能耗均衡的WSN非均匀分簇路由协议

在无线传感器网络(WSN)的分簇路由算法中,节点间能耗不均容易引发 “能量空洞”现象,影响整个网络的性能。针对这个问题,提出了一种基于博弈论能耗均衡的非均匀分簇路由(GBUC)算法。该算法在分簇阶段,采用非均匀分簇结构,簇的半径由簇头到汇聚节点的距离和剩余能量共同决定,通过调节簇头在簇内通信的能耗和转发数据的能耗来达到能耗的均衡;在簇间通信阶段,通过建立一个以节点剩余能量和链路可靠度为效益函数的博弈模型,利用其纳什均衡的解来寻找联合能耗均衡、链路可靠性的最优传输路径,从而提高网络性能。仿真结果表明:与能量高效的非均匀分簇(EEUC)算法和非均匀分簇节能路由(UCEER)算法相比,GBUC算法在均衡节点能耗、延长网络生命周期等性能方面有显著的提高。     

面向目标跟踪的传感器网络睡眠调度协议

移动目标跟踪是无线传感器网络中的一项重要应用,将睡眠调度机制引入到目标跟踪算法中可以大大降低能耗。针对目标跟踪的实际需求,提出一种面向目标跟踪的传感器网络睡眠调度协议。根据目标跟踪不同阶段,分别设计了目标跟踪前和跟踪过程中传感器节点的睡眠调度机制;另外给出了目标丢失时,如何唤醒节点继续跟踪目标的调度策略。结果表明:该算法能够在保证跟踪质量的同时,降低跟踪能耗。     

Understanding optimal data gathering in the energy and latency domains of a wireless sensor network

The problem of optimal data gathering in wireless sensor networks (WSNs) is addressed by means of optimization techniques. The goal of this work is to lay the foundations to develop algorithms and techniques that minimize the data gathering latency and at the same time balance the energy consumption among the nodes, so as to maximize the network lifetime. Following an incremental-complexity approach, several mathematical programming problems are proposed with focus on different network performance metrics. First, the static routing problem is formulated for large and dense WSNs. Optimal data-gathering trees are analyzed and the effects of several sensor capabilities and constraints are discussed, e.g., radio power constraints, energy consumption model, and data aggregation functionalities. Then, dynamic re-routing and scheduling are considered. An accurate network model is proposed that captures the tradeoff between the data gathering latency and the energy consumption, by modeling the interactions among the routing, medium access control and physical layers.For each problem, extensive simulation results are provided. The proposed models provide a deeper insight into the problem of timely and energy efficient data gathering. Useful guidelines for the design of efficient WSNs are derived and discussed.     

基于虚拟力的WSNs能量高效分簇路由协议

作为无线传感器网络(wireless sensor networks,WSNs)的关键技术之一,分簇路由协议因其可扩展性较强及能耗较低等优势,逐渐成为WSNs路由协议的研究热点.如何对簇首进行最佳化选取,是提高分簇路由协议性能的关键.通过揭示不同场景中的簇首数量及网络能耗之间的映射关系,以能耗最小化为目标,构建了簇首最...     

An Approach of Distributed Joint Optimization for Cluster-based Wireless Sensor Networks

Wireless sensor networks (WSNs) are energyconstrained, so energy saving is one of the most important issues in typical applications. The clustered WSN topology is considered in this paper. To achieve the balance of energy consumption and utility of network resources, we explicitly model and factor the effect of power and rate. A novel joint optimization model is proposed with the protection for cluster head. By the mean of a choice of two appropriate sub-utility functions, the distributed iterative algorithm is obtained. The convergence of the proposed iterative algorithm is proved analytically. We consider general dual decomposition method to realize variable separation and distributed computation, which is practical in large-scale sensor networks. Numerical results show that the proposed joint optimal algorithm converges to the optimal power allocation and rate transmission, and validate the performance in terms of prolonging of network lifetime and improvement of throughput.