Actor-Critic-Based UAV-Assisted Data Collection in the Wireless Sensor Network

Wireless Sensor Network(WSN)is widely utilized in large-scale distributed unmanned detection scenarios due to its low cost and flexible installation.However,WSN data collection encounters challenges in scenarios lacking communication infrastructure.Unmanned aerial vehicle(UAV)offers a novel solution for WSN data collection,leveraging their high mobility.In this paper,we present an efficient UAV-assisted data collection algorithm aimed at minimizing the overall power consumption of the WSN.Firstly,a two-layer UAV-assisted data collection model is introduced,including the ground and aerial layers.The ground layer senses the environmental data by the cluster members(CMs),and the CMs transmit the data to the cluster heads(CHs),which forward the collected data to the UAVs.The aerial network layer consists of multiple UAVs that collect,store,and forward data from the CHs to the data center for analysis.Secondly,an improved clustering algorithm based on K-Means++is proposed to optimize the number and locations of CHs.Moreover,an Actor-Critic based algorithm is introduced to optimize the UAV deployment and the association with CHs.Finally,simulation results verify the effectiveness of the proposed algorithms.

Dynamic Coverage with Wireless Sensor and Actor Networks in Underwater Environment

This paper studies the problem of dynamic coverage with wireless sensor and actor networks (WSANs) in underwater environment. Different from most existing works, the WSANs consist of two kinds of nodes, i.e., sensor nodes (SNs) which cannot move autonomously and actor nodes (ANs) which can move autonomously according to the performance requirement. The problem of how to coordinate two kinds of nodes to facilitate dynamic coverage in underwater environment is challenging due to their heterogeneous capabilities. To reduce redundancy of communication links and improve connectivity between ANs and SNs in underwater WSANs, a min-weighted rigid graph based topology optimization scheme is first developed, such that the underwater communication energy consumption can be saved. With the optimized topology, a dynamic coverage strategy is proposed to improve the coverage among SNs and ANs for underwater WSAN where underwater fluid motions are considered. Furthermore, it is proved that the network coverage area is connected by using the min-weighted rigid graph. Finally, simulation results are presented to show the effectiveness of the main results. © 2014 Chinese Association of Automation.

Enhancing real-time performance via controlled actor relocation in wireless sensor and actor networks

Actors'relocation is utilized during the network initialization to enhance real-time performance of wireless sensor and actor networks(WSANs)which is an important issue of WSANs.The actor deployment problem in WSANs is proved NP-Hard whether the amount of actors is redundant or not,but to the best of our knowledge,no effective distributed algorithms in previous research can solve the problem.Thus two actor deployment strategies which need not the boundary control compared with present deployment strategies are proposed to solve this problem approximately based on the Voronoi diagram.Through simulation experiment,the results show that our distributed strategies are more effective than the present deployment strategies in terms of real-time performance,convergence time and energy consumption.

Recharging Sensor Nodes Using Implicit Actor Coordination in Wireless Sensor Actor Networks

Wireless sensor actor networks are composed of sensor and actor nodes wherein sensor nodes outnumber resource-rich actor nodes. Sensor nodes gather information and send them to a central node (sink) and/or to actors for proper actions. The short lifetime of energy-constrained sensor nodes can endanger the proper operation of the whole network when they run out of power and partition the network. Energy harvesting as well as minimizing sensor energy consumption had already been studied. We propose a different approach for recharging sensor nodes by mobile actor nodes that use only local information. Sensor nodes send their energy status along with their sensed information to actors in their coverage. Based on this energy information, actors coordinate implicitly to decide on the timings and the ordering of recharges of low energy sensor nodes. Coordination between actors is achieved by swarm intelligence and the replenishment continues during local learning of actor nodes. The number of actors required to keep up such networks is identified through simulation using VisualSense. It is shown that defining the appropriate number of actor nodes is critical to the success of recharging strategies in prolonging the network lifetime.

The ZigBee Based Wireless Sensor and Actor Network in Intelligent Space Oriented to Home Service Robot

In the study of intelligent space oriented to home service robot, an important technology is how to construct an communication network which has the characters of high reliability and easy building. In this paper, based on the characteristics of ZigBee protocol, ZigBee technology is used to construct a wireless sensor and actor network. Several intelligent services based on ZigBee wireless sensor and actor network are shown to certify the reliability of this communication network. ZigBee wireless sensor and actor network builds an information bridge for the components in the intelligent space, the spatially distributed devices are connected together seamlessly. With this network, robot can share the mass information in the intelligent space and improve its performance with 'light-packs', devices in intelligent space, such as lamp, curtain can be controlled autonomously.

WSN/WSAN中的时间同步算法研究

无线传感器网络实现了人类对现实世界的观测,由于网络中节点可以单独监测,因此在这样的网络中节点间需要时间同步,以确定事件发生的顺序。阐述了WSN时间同步的相关问题,并从同步报文传递方式的角度详细介绍了几种时间同步算法;从定性和定量两个方面对算法进行了比较。在此基础上,针对WSAN的新特点提出算法融合的设计思想。

DGR:dynamic gradient-based routing protocol for unbalanced and persistent data transmission in wireless sensor and actor networks

This paper is concerned with the routing protocol design for large-scale wireless sensor and actor networks (WSANs).The actor-sensor-actor communication (ASAC) strategy is first proposed to guarantee the reliability of persistent actor-actor communication.To keep network connectivity and prolong network lifetime,we propose a dynamic gradient-based routing protocol (DGR) to balance the energy consumption of the network.With the different communication ranges of sensors and actors,the DGR protocol uses a data load expansion strategy to significantly prolong the network lifetime.The balance coefficient and the routing re-establishment threshold are also introduced to make the tradeoff between network lifetime and routing efficiency.Simulation results show the effectiveness of the proposed DGR protocol for unbalanced and persistent data transmission.

设施环境中WSAN执行器节点协作算法研究

针对WSN技术应用于设施作物无法摆脱人力监控的局面,提出将WSAN技术应用于设施作物,并针对应用中存在的执行器节点之间的协作问题提出了一种执行器节点协作算法。首先利用执行器节点重新部署算法将执行器节点部署到执行器节点执行区域的中间,然后利用基于密封第一价的拍卖算法将事件区域发生的任务进行拍卖与求解。仿真试验结果表明所提协作算法可以实现设施作物应用中的控制任务被WSAN网络中的执行器节点以协作的方式有效并快速地分配和执行。

WSAN网络密钥管理模型的研究

无线传感器和反应器网络(wireless sensor and actor network,WSAN)由三种具有不同级别能力和作用的节点构成,节点的异构性导致单纯使用一种安全模型将无法满足不同节点对性能和安全性的要求。为此,本文首次提出了一种复合式的安全模型,根据节点的能力和作用将WSAN网络分为两层,不同层通过应用不同的安全机制,实现不同级别的安全服务。另外,本模型通过多种方式降低系统开销,力求达到安全和性能的平衡。

基于多反应节点下WSANs路由协议研究

针对多个反应节点环境中现有无线传感器网络路由协议不能完全满足无线传感反应网络(WSANs)对能耗和实时性需求的问题,利用J-Sim对WSANs的仿真功能,设计并实现适应单反应节点选择模式的WSANs路由协议BHOER,给出仿真数据及性能分析,实验结果表明,BHOER较好地满足WSANs的应用需求。

基于地理路由和参与者协作模型的WSAN的通信机制

针对无线传感器和参与者网络的通信机制进行了研究。首先,提出了一种主动位置管理机制,它基于移动参与者发送给传感器的更新消息和 Voronoi 图限制的参与者范围,从而使传感器采用先前接收到的更新卡尔曼滤波来预测参与者的移动;然后,提出了一种基于地理路由的最佳能量感知转发规则作为传感器参与者之间的通信,并采用功率控制来控制数据传输过程的时延,通过迫使多个参与者共享事件区域产生的流量来处理网络拥塞;最后,基于多个并发事件的特征,提出了一种参与者参与者之间的协作模型来协调它们之间的运动,以最佳地完成任务。性能仿真结果表明,提出的关于无线传感器和参与者网络的协作通信机制能够有效地减少端到端时延、能量消耗和分组丢失百分比。

基于容量约束的WSANs路由算法的研究

在无线传感反应网络通过引入具有丰富资源、甚至可以移动的反应节点,极大地增强了现有的无线传感器网络的功能和应用范围。针对距离反应节点越近传感节点能量消耗越快的问题,研究了基于容量约束的最大跳数最小化的问题,并在此基础上提出了一种全局近似算法。仿真实验表明,该算法能通过设置节点的容量约束,限制节点每轮转发某个事件的最大报文数,以降低单个节点的最大能耗,达到延长网络生存时间的目的。

SAS模式下WSANs路由协议的分析与研究

针对SAS模式下现有WSNs(Wireless Sensor Networks)路由协议不能很好地满足WSANs(Wireless Sensor and Actor Net-works)应用的需求的问题,利用J-Sim对WSANs的仿真功能,设计并实现了适应SAS模式的WSANs路由协议BHOER,同时给出了仿真数据及性能分析,实验结果表明BHOER很好地满足了WSANs的路由需求。

基于QPSO的WSAN中执行器优化部署研究

为了提高WSAN的工作效率,在量子粒子群算法的基础上,提出一种WSAN中执行器节点的优化部署策略。该策略中多个粒子群在独立搜索解空间的同时,以一定的通信频率共享最优值。仿真结果表明,该部署策略可提高节点的实时覆盖率,并与最新的WSAN部署策略进行了对比。

WSANs中基于线性规划的单反应节点选择算法的研究

介绍了无线传感器反应网络中单个反应节点选择算法的特点,并提出一种基于线性规划方案的最优选择算法MCT。最后就MCT算法的两种情形进行了仿真分析。

WSAN中基于节点分区的能耗均衡路由协议

传感器节点能量消耗不均衡,是影响无线传感器/执行器网络寿命的关键问题之一。文章提出基于节点分区的能耗均衡路由协议(ERPNP),该协议在保证网络连通性的基础上,通过簇内传感器节点分区、传感器节点到执行器节点路由选择、执行器节点到sink节点路由选择等步骤,使传感器节点的发射功率尽可能的小,同时下一跳节点距离执行器节点越来越近,即选择较多节点较小发射功率的传输路径,避免选择较少节点较大发射功率的传输路径,利用较多节点分担传输能量,均衡节点能耗,提高网络寿命。仿真实验表明,相比于传统协议,ERPNP协议能够显著延长网络生存时间。

WSAN中任务智能执行的SDN控制模型

软件定义网络(SDN)是一种新技术,为了提高WSAN的通信效率以及可扩展性,讨论了将SDN应用于WSAN的模型上.具体模型包括一个具有全新控制平面的三层架构、相应的系统实体以及加强了的协议栈.实验结果表明,SDN采用控制和转发相分离的架构,使复杂的网络管理变得简单和方便.

分布式融合算法在WSANs中的性能分析

在无线传感器执行器中,执行器节点接收传感器节点传来的信息并执行相应的动作。为了满足执行器节点及时地采取行动,无线传感器执行器网络对时延有严格的限制。构建了一种一般性的分布式融合算法并与集中式融合算法比较。通过从网络传输时延、节点能量消耗、网络寿命、有效传输次数等方面分析了这种算法在无线传感器执行器网络中的特性。在三种典型拓扑结构下的仿真实验表明,在相同条件下,分布式融合算法比集中式融合算法具有更小的网络传输时延,更长的网络寿命,同时节点的能量消耗更加均匀。

WSAN多反应节点多传感节点模型的数据传输算法

无线传感反应网络由传感节点和反应节点组成,传感节点将监测到的数据发送到反应节点时,通常采用单反应节点传输模型或多反应节点传输模型。针对最近为提高系统容错能力而提出的一种新的多反应节点多传感节点模型,提出了传感节点发送数据到反应节点的基于组播的新算法。实验证明这种算法可以有效地降低数据传输能耗,从而在提高网络容错能力的同时,改善系统的能量有效性。