蔬菜温室WSN路由算法研究

以无线传感器网络在蔬菜温室环境监控中的应用为目的,研究几种常用自组网路由算法原理。通过对ABR、TORA、DSR、DSDV、AODV等不同路由算法的分类归纳和各自优缺点对比,得出AODV算法因在降低开销的同时还能减小通信延时而最适用于无线传感器网络的结论,因此以实际应用为目的对AODV算法的工作原理进行研究和梳理。使用NS2和NAM网络仿真工具对使用AODV算法的无线传感器网络进行模拟场景仿真,使用gwark和gnuplot工具对仿真数据进行分析,重点研究一定区域面积下节点数量增加时网络传输延时和丢包率的变化,得出应用场景确定时节点数量对通信质量的影响关系,为今后WSN在蔬菜温室中的实际应用提供理论依据。     

基于ZigBee的工厂化水产养殖溶解氧在线监控系统设计的研究

为了采用分散控制方式对工厂化水产养殖溶解氧进行监控,提出了基于ZigBee的溶解氧在线监控系统。系统采用集散控制模式,分为终端节点、路由节点和网关节点以及监控中心4个层次。终端节点采集养殖池中溶氧量,然后通过路由节点汇聚到网关节点,并根据溶氧量对与之连接的增氧机进行控制。网关节点将所有终端节点数据传输给监控中心,并接收监控中心的控制指令,进而通过各终端节点控制增氧机。同时,监控中心对数据进行存储、统计和分析,并产生控制指令。ZigBee节点采用CC2430作为核心芯片,使用ZigBee2006协议栈实现无线网络节点之间的通信。结果表明：该系统稳定性较好,部署灵活、容易扩展,满足了工厂化水产养殖的要求。实现了对溶解氧的在线实时监测及对增氧机的有效控制,降低了养殖成本。     

一种基于距离和角度的无线传感器网络GPSR协议

传感器节点能量是影响无线传感器网络的生存周期的关键因素,基本的GPSR协议所使用的贪婪算法忽略了角度因素对下一跳选择的影响,在转发失败遇到空洞问题时只能进行周边边界转发算法,以损耗节点能量为代价。为了节约节点能量,延长网络生存周期,从改进GPSR协议出发,综合考虑距离和角度这两个因素解决路由过程中的空洞问题。仿真实验表明,改进后的协议是网络节点消耗大大减少,网络生存时间为300 s,长于基本GPSR协议下的200 s。该协议缩短了路径长度,节约节点能量,减少能量的消耗,延长了网络生存时间。     

基于MQTT协议的移动冷库智能监控系统设计

随着人们对生鲜果蔬需求的增加,我国冷链物流得到快速发展。移动冷库由于其综合成本低,使用方便灵活的优势得到广泛的应用。针对移动冷库分布式、全方位监控的需求,设计了基于MQTT协议的智能移动冷库监控系统。该系统将物联网技术、传感器技术和无线通信技术等诸多技术相结合,采用MQTT协议实现冷库与用户之间消息传递,可实时监测冷库的运行参数,并能远程控制冷库工作模式,设定目标温度,极大提高冷库的智能化水平,具有较大的应用价值。     

物联网技术在农田环境监测中的应用

为了实现农业的自动化管理,为实现农业精准生产,并为科学研究提供全面信息,设计了基于物联网的农田环境监测系统,系统由传感层、传输层和应用层构成。开发了结构灵活、通用性强的路由和协调器节点,节点通过标准模拟接口与传感器连接,在此基础之上构建了具有高可靠性和灵活性的无线传感器网络,该网络能实时感知作物生长环境信息,并将数据可靠地传输到远端服务器管理系统。田间试验表明：基于物联网农田综合环境信息自动监测系统运行稳定、可靠,为科学预测和科学种植提供了依据。     

向环境采集能量的WSN中的自适应周期机会路由算法

如何让可以采集能量的节点充分利用环境能量,从而提高整个网络持续高效工作的能力是在能量采集无线传感网中的关键问题。目前的研究主要集中在如何均衡分配可进行能量采集的节点的能量,从而在提高节点寿命的基础上,实现网络寿命延长,但是仍然存在环境能量变化的不确定性导致的风险。笔者提出了自适应周期机会路由算法,首先对节点进行地理分区,再分配优先级,最后进行优化后路由处理。仿真结果表明,该算法能实现对环境能量更加高效的利用,并能有效提升网络的吞吐量和网络效率。     

XMPP应用于物联网通讯协议的研究

为解决物联网系统之间的信息交换、互联共享问题,探索一种以XMPP协议为基础的物联网通讯协议。本协议定义了物联网端、网关、服务器3个角色,服务器承担各物联网的信息记录、连接管理和信息路由等功能,网关承担不同物联网系统之间的互联互通,各物联网之间相互通信的指令和数据采用XML数据流,采用类似电子邮件地址结构进行寻址。该标准技术协议在农情监测系统中进行了试用,能同时采集不同物联网系统的数据,相互之间还能进行数据交换,可促进物联网系统的整合和综合应用。     

基于无线传感器网络的森林火情实时监测系统

为了实现森林火情监测过程的自动化、智能化和网络化,提出基于无线传感器网络的森林火情实时监测系统。该系统由无线传感监测网络和监控中心2部分组成,可实时、在线、精确获取森林气象及火场环境信息,具有部署灵活、维护方便、成本低廉、扩展性好等优点。移动节点的引入进一步加强了消防人员的安全保障和监测系统的可靠性。将该系统应用在情况复杂多变、实时性要求很高的森林防火,能显著提高救灾效率,减少火灾所带来的人员和财产损失。     

纸板板框式精滤机

由北京东方孚德技术发展中心研发生产的GLA85谷物冷却机可对粮食仓储的出风温、湿度进行全自动精确控制，具有运行稳定、操作方便、投资少、利用率高的优点，还可移动到各仓库轮流使用。     

On-demand routing algorithm based on load balancing and mobility prediction in wireless mobile Ad hoc network

The traditional routing protocol for wireless mobile ad hoc networks is unable to achieve balanced energy consumption and could not adapt to the dynamic topology changes well.A novel on-demand rooting algorithm is proposed based on load balancing and mobility prediction.The proposed rooting algorithm excludes the unstable links in routing discovery,and allows the node with more energy forward the routing request packet preferentially.In addition,it adopts the active local routing recovery strategy by predicting the link connection time,and finishes the repair work before the link being actually failure.The simulation experiments demonstrate that,comparing with the traditional AODV protocol,with slight increase of the rooting control overhead,the proposed algorithm increases the average packet delivery ratio,decreases the average end-to-end delay of the data packets,and achieves load balancing in the network and prolong the life-span of the network,which shows the proposed algorithm is highly practical.     

Intrusion Detection Technology in Ad Hoc Network

With the rapid development of wireless network and mobile computing,the security of network becomes more important.As one of wireless mobile network,mobile Ad hoc network has new vulnerabilities that do not exist in a fixed wired network,and is susceptible to attacks.This paper introduces some methods which used in intrusion detection system and provides a new model of system based on multi-layer integrated distributed technology,especially recommend the protocol analyzing method in this system.     

Recommending Trust Model Based on Behavior for Distributed CA in MANET

Mobile Ad Hoc Networks(MANET) is a multi-ho Pand instant self-organized autonomous system of a collection of wireless mobile nodes.A multi-domain full-distributed Certification Authorities system model was proposed founding on its trait of territorial communication.The thesis researched this model and proposes a new model for the interoperability between virtual Certification Authorities named extended recommending trust model based on behavior.It can improve the system's security,retractility and robustness by dynamic trust chain maintenance with feedback information in the actual course.     

An improved HEED clustering algorithm for Wireless Sensor Network

In wireless sensor network, routing protocols which based on clustering have the advantages of energy consumption, topology management and data fusion. The HEED protocol, which generates cluster heads based on distributed algorithm, drives up the rate of clustering and creates well distributed cluster heads. However, it does not consider the mobility of nodes in the network. When the distance between neighbor nodes has changed, the AMRP method which decides the node belongs to different cluster heads would cause problems such as high energy consumption, short lifetime of network and so on. Responding to these problems, the paper proposes the S HEED, a clustering algorithm based on stability, which chooses the stability as a parameter of nodes when choosing a cluster head. With S HEED algorithm, the high energy consumption problem among cluster nodes and cluster heads caused by the mobility is tackled. The simulation experiment demonstrates that the S HEED algorithm lower the energy consumption of cluster heads and prolongs the network lifetime.     

Routing protocol of the wireless sensor networks for bridge health monitoring

By analyzing the reason that why the existing routing protocols cannot be applied to the wireless sensor networks for bridge health monitoring, a new routing protocol is proposed. Since the locations of the collecting modules are fixed, the proposed protocol exchanges the routing information between the neighbor nodes by adjusting the exchange cycle according to reliability of the modules. For the low routing security requirement, while to increase the routing efficient, the middle nodes replying the routing requirements with variable thresholds is introduced. In order to make full use of information in route discovering procedure, the backup routes mechanism is adopted. The proposed protocol can efficiently forward data and is suitable for the bridge health monitoring.     

Improved WPAN meshed adaptive tree routing algorithm

To expand network coverage and enhance the reliability of wireless personal area network (WPAN), the problem of address overflow resulting from applying the meshed adaptive tree algorithm in large scale mesh network wis studied. By dividing the entire network into smaller sub networks, the subarea meshed adaptive tree wis constructed. An improved meshed adaptive tree routing algorithm wis proposed employing the hierarchical topology structure of the subarea meshed adaptive tree. Experimental results show that the algorithm expands the network coverage without increasing the routing overhead and the network load. It also effectively reduces the end to end delay and increases the packet delivery ratio and communication efficiency. It maintains a good performance in the networks with different scales and provides a theoretical basis for enhancing the coverage and reliability of WPAN.     

Trust management scheme based on community model for mobile Ad hoc networks

The security issues in mobile Ad hoc network, especially caused by inner malicious nodes are analyzed. By tracking the behavior of nodes, trust level of each node can be evaluated and managed; then actions of malicious nodes will be constrained and the security and reliability of entire network are enhanced. According to the features of Ad hoc. The scheme proposed in not only extends the conception of trust but also include the trust computation model and trust management mechanism. Simulation experiments show the novel scheme is more efficient than other trust schemes in traditional protocols.     

Investigation of TCP Veno Performance over Wirless Ad Hoc Network

TCP Veno Performance over Wireless Ad Hoc was studied. The performance of TCP Veno over SANET and MANET were simulated. The results show that the performance of TCP Veno is not good enough when it is working on the Wireless Ad Hoc, and is worse than TCP Reno over the Wireless one hopnetwork.     

A Deadlock-free Routing Algorithm for Locally Twisted Cubes

The n-dimensional locally twisted cube(LTQ_(n)) is a newly introduced interconnection network for parallel computing.First, the authors illustrate that there exists deadlock in the minimal routing algorithm.Second,by employing the common virtual network dividing technique,a new routing algorithm is presented,which is proved to be deadlock-free.By exploring the property that one LTQ_(n) consists of one n-1-dimensional hypercube(Q_(n-1)) and one n-1-dimensional 2-twisted cube(Q_(n1,2)),the authors apply the existing adaptive routing strategies for Q_(n-1) and Q_(n-1,2) to induce an adaptive routing scheme for LTQ_(n).So the algorithm can route adaptively in the Q_(n-1)0 or in the Q_(n-1,2)1.     

Distributed Generation of Shared RSA Keys in Mobile Ad Hoc Networks

Mobile Ad hoc NETworks(MANET) is a totally new concept in which mobile nodes are able to communicate together over wireless links in an independent manner,without needing any fixed physical infrastructure and centralized organizational/administrative infrastructure.However,the nature of ad hoc networks makes them very vulnerable to security threats.Generation and distribution of shared keys for CA(Certification Authority)is challenging in security solution based on distributed PKI/CA.Those solutions that have been proposed in the literature and some issues are discussed.This paper propose the solution of distributed generation of shared CA keys based on threshold RSA cryptosystems,with which the security and robustness of system is enhanced.