REMUDA: 一个实用地无线传感网络拓扑控制和数据转发机制

In wireless sensor networks, topology control plays an important role for data forwarding efficiency in the data gathering applications. In this paper, we present a novel topology control and data forwarding mechanism called REMUDA, which is designed for a practical indoor parking lot management system. REMUDA forms a tree-based hierarchical network topology which brings as many nodes as possible to be leaf nodes and constructs a virtual cluster structure. Meanwhile, it takes the reliability, stability and path length into account in the tree construction process. Through an experiment in a network of 30 real sensor nodes, we evaluate the performance of REMUDA and compare it with LEPS which is also a practical routing protocol in TinyOS. Experiment results show that REMUDA can achieve better performance than LEPS.     

A unified optimal planner for autonomous parking vehicle

In order to reduce the controlling difficulty caused by trajectory meandering and improve the adaptability to parking into regular lots, a versatile optimal planner (OP) is proposed. Taking advantage of the low speed specificity of parking vehicle, the OP algorithm was modeled the planning problem as a convex optimization problem. Collision-free constraints were formalized into the shortest distance between convex sets by describing obstacles and autonomous vehicle as affine set. Since employing Lagrange dual function and combining KKT conditions, the collision-free constraints translated into convex functions. Taking the national standard into account, 5 kinds of regular parking scenario, which contain $0^\circ$, $30^\circ$, $45^\circ$, $60^\circ$ and $90^\circ$ parking lots, were designed to verify the OP algorithm. The results illustrate that it is benefit from the continuous and smooth trajectory generated by the OP method to track, keep vehicle''s stability and improve ride comfort, compared with A* and hybrid A* algorithms. Moreover, the OP method has strong generality since it can ensure the success rate no less than 82% when parking planning is carried out at the start node of 369 different locations. Both of evaluation criteria, as the pear error and RMSE in x direction, y axis and Euclidean distance d, and heading deviation $\theta$, are stable and feasible in real tests, which illustrates that the OP planner can satisfy the requirements of regular parking scenarios.     

A cross-layer fault tolerance management module for wireless sensor networks

It is a well-established fact that wireless sensor networks (WSNs) are very power constraint networks, but besides this, they are inherently more fault-prone than any other type of wireless network and their protocol design is very application specific. Major reasons for the faults are the unpredictable wireless communication channel, battery depletion, as well as fragility and mobility of the nodes. Furthermore, as traditional protocol design methods have proved inadequate, the cross-layer design (CLD) approach, which allows for interactions between different layers, providing more flexible and energy-efficient functionality, has emerged as a viable solution for WSNs. In this study we define a fault tolerance management module suitable to the requirements, limitations, and specifics of WSNs, encompassing methods for fault detection, fault prevention, fault management, and recovery. The suggested solution is in line with the CLD approach, which is an important factor in increasing the network performance. Through simulations the functionality of the network is evaluated, based on packet loss, delay, and energy consumption, and is compared with a similar solution not including fault management. The results achieved support the idea that the introduction of a unified approach to fault management improves the network performance as a whole.     

SmallWorld Model-Based Polylogarithmic Routing Using Mobile Nodes

The use of mobile nodes to improve network system performance has drawn considerable attention recently. The movement-assisted model considers mobility as a desirable feature,where routing is based on the store-carry-forward paradigm with random or controlled movement of resource rich mobile nodes.The application of such a model has been used in several emerging networks,including mobile ad hoc networks(MANETs),wireless sensor networks(WSNs),and delay tolerant networks(DTNs).It is well known that mobility increases the capacity of MANETs by reducing the number of relays for routing,prolonging the lifespan of WSNs by using mobile nodes in place of bottleneck static sensors,and ensuring network connectivity in DTNs using mobile nodes to connect different parts of a disconnected network.Trajectory planning and the coordination of mobile nodes are two important design issues aiming to optimize or balance several measures, including delay,average number of relays,and moving distance.In this paper,we propose a new controlled mobility model with an expected polylogarithmic number of relays to achieve a good balance among several contradictory goals,including delay,the number of relays,and moving distance.The model is based on the small-world model where each static node has"short"link connections to its nearest neighbors and"long"link connections to other nodes following a certain probability distribution.Short links are regular wireless connections whereas long links are implemented using mobile nodes.Various issues are considered,including trade-offs between delay and average number of relays,selection of the number of mobile nodes,and selection of the number of long links.The effectiveness of the proposed model is evaluated analytically as well as through simulation.     

HierTrack: an energy-efficient cluster-based target tracking system forwireless sensor networks

Target tracking is a typical and important application of wireless sensor networks(WSNs).Existing target tracking protocols focus mainly on energy efficiency,and little effort has been put into network management and real-time data routing,which are also very important issues for target tracking.In this paper,we propose a scalable cluster-based target tracking framework,namely the hierarchical prediction strategy(HPS),for energyefficient and real-time target tracking in large-scale WSNs.HPS organizes sensor nodes into clusters by using suitable clustering protocols which are beneficial for network management and data routing.As a target moves in the network,cluster heads predict the target trajectory using Kalman filter and selectively activate the next round of sensors in advance to keep on tracking the target.The estimated locations of the target are routed to the base station via the backbone composed of the cluster heads.A soft handoff algorithm is proposed in HPS to guarantee smooth tracking of the target when the target moves from one cluster to another.Under the framework of HPS,we design and implement an energy-efficient target tracking system,HierTrack,which consists of 36 sensor motes,a sink node,and a base station.Both simulation and experimental results show the efficiency of our system.     

Performance of IEEE 802.15.4 Clusters with Power Management and Key Exchange

The IEEE 802.15.4 specification is a recent low data rate wireless personal area network standard.While basic security services are provided for,there is a lack of more advanced techniques which are indispensable in modern personal area network applications.In addition,performance implications of those services are not known.In this paper,we describe a secure data exchange protocol based on the ZigBee specification and built on top of IEEE 802.15.4 link layer.This protocol includes a key exchange mechanism.We assume that all nodes are applying power management technique based on the constant event sensing reliability required by the coordinator.Power management generates random sleep times by every node which in average fairly distributes the sensing load among the nodes.Key exchange is initiated by a cluster coordinator after some given number of sensing packets have been received by the coordinator.We develop and integrate simulation model of the key exchange and power management technique into the cluster's reliable sensing function.We evaluate the impact of security function and its periodicity on cluster performance.     

NRCE： A New Random Cluster Election Algorithm

The Intrusion Detection System （IDS） is a secure solution for Mobile Ad Hoc Networks （MANET）. Cluster management can improve cooperating detection ability of mobile nodes. In this paper, a New Random Cluster Election （NRCE） algorithm, which is applied to the intrusion detection system for MANET, is proposed based on analyzing some popular cluster algorithms. NREC considering security and fairness adequately is working in a distrustful mode where mobile nodes distrust each other and the process of electing clusterhead is random. It is a new method for cluster management of IDS for MANET.     

New Distributed Positioning Algorithm Based on Centroid of Circular Belt for Wireless Sensor Networks

This paper presents a new distributed positioning algorithm for unknown nodes in a wireless sensor network.The algorithm is based exclusively on connectivity.First,assuming that the positions of the anchor nodes are already known,a circular belt containing an unknown node is obtained using information about the anchor nodes that are in radio range of the unknown node,based on the geometric relationships and communication constraints among the unknown node and the anchor nodes.Then,the centroid of the circular belt is taken to be the estimated position of the unknown node.Since the algorithm is very simple and since the only communication needed is between the anchor nodes and the unknown node,the communication and computational loads are very small.Furthermore,the algorithm is robust because neither the failure of old unknown nodes nor the addition of new unknown nodes influences the positioning of unknown nodes to be located.A theoretical analysis and simulation results show that the algorithm does not produce any cumulative error and is insensitive to range error,and that a change in the number of sensor nodes does not affect the communication or computational load.These features make this algorithm suitable for all sizes of low-power wireless sensor networks.     

A Fuzzy Inference System for Increasing of Survivability and Efficiency in Wireless Sensor Networks

The nodes of a WSNs （wireless sensors network） are composed of small devices capable of sensing and transmitting data related to some phenomenon in the environment. These devices, named sensor nodes, have severe constraints, such as lower processing and storage capacity, and mainly they have severe constraints related to battery energy. Therefore, the developing of strategies to reduce the power consumption is one of the main challenges in WSNs, and thereby helping to increase the survivability and efficiency of these networks. This paper proposes a new approach to help multi-path routing protocols to choose the best route based on Fuzzy Inference Systems and ACO （ant colony optimization）. The Fuzzy System is used to estimate the degree of the route quality, based on the number of hops and the lowest energy level among the nodes that form the route. The ACO algorithm is used to adjust the rule base of the fuzzy system in order to improve the classification strategy of the route, and hence increasing the energy efficiency and the survivability of the network. The simulations showed that the proposal is effective from the point of view of the energy, the number of received messages, and the cost of received messages when compared against other approaches.     

Energy saving in wireless sensor networks

With the development of low-cost processor, memory, and radio technologies, it becomes possible to build inexpensive wireless micro-sensor nodes. However, energy is the biggest constraint to wireless sensor capabilities and such constraint combined with a typical deployment of large numbers of sensor nodes have posed many challenges to the design and management of sensor networks. Due to their ad-hoc deployment in hazardous environment, once sensor nodes are deployed in a sensor network, they cannot be easily replaced or recharged. Thus, energy saving acts as one of the hottest topics in wireless sensor networks （WSNs） and hence several energy conservation schemes have been proposed in the literature. In this work, we will make a short survey on the main techniques used for energy conservation in sensor networks. Specifically, we will focus primarily on duty cycling schemes which represent the most suitable technique for energy saving. Moreover, we will also survey in-network processing and network coding techniques which can guarantee a significant amount of energy saving in packet transmission. Finally, we will make a review on some communication protocols proposed for sensor networks.     

智能车位锁管理系统设计

为了解决广大市民停车难、停车贵等问题,将ZigBee与WiFi无线通信技术相结合,并引入实时时钟模块和继电器模块,通过软、硬件开发设计了智能车位锁管理系统.当有取车或停车需求时,手机用户通过WiFi接入网络并发送需求指令,ZigBee协调器收到通信请求后发送无线数据到指定终端,从而控制车位锁的升降.此外,该系统利用RTC实时时钟模块可计算停车时间并扣取费用.通过实验验证了该车位锁管理系统的有效性.本管理系统的设计为全市停车场进行联网提供了一种新方案.     

基于无线传感网络的停车引导系统设计

为了提高停车效率,以Jennic公司的无线低功耗嵌入式处理器JN5148为核心,设计了一套基于无线传感网络的停车引导系统。设计了一种低功耗的传感器节点电路,并对JenNet协议栈进行了应用。该系统已经应用于停车场中,实践证明该方法能代替有线线圈,实现引导功能;同时,该系统采用无线通信,小巧,方便安装。     

基于无线通信的智能泊车系统设计

自动泊车是车辆辅助驾驶系统中的一项关键技术.当泊车空间较小时,现有的泊车技术无法发挥作用.设计了一种基于无线通信的新型智能泊车方法,引入无线通信协同泊靠的概念,利用通信网络共享资源信息;使用多类型传感器采集车位信息,多MCU共同规划泊车路径,调整已泊靠车辆位置,为需要泊靠的车辆提供足够空间,从而通过多车协同最大化利用泊车空间.通过实验验证,该方法与现有泊车技术相比,在同等条件下,泊车空间利用率提高20％以上.     

基于ZigBee网络的停车场管理系统

在大型停车场如何快速停车是管理者与停车者之间存在的最大的难题。为了解决这个困扰社会管理的难题,文中提出了一种基于ZigBee与S3C2440的大型停车场管理系统解决方案。该系统采用CC2430和超声波传感器采集与传输停车场车位信息,并用S3C2440和MFRC522模块解决停车场收费问题,用LED点阵屏实时显示停车场车位信息以及引导停车者快速停车。整个系统能够智能地管理与引导停车者快速停车。     

基于ARM的智能车位锁远程控制系统设计

针对目前普遍存在停车难的问题,运用物联网技术和无线通信技术,构建由服务器、移动终端和控制器组成三级网络结构的智能车位远程管理系统.实现服务器、移动终端、控制器和车位锁之间的互联,并通过GSM与互联网连接,用户可通过移动终端进行预定车位、出租车位等操作.实现对城市停车场车位集中管理,分散控制,车位资源的共享,是物联网技术在创建新型智慧城市方面的应用场景之一.     

基于ZigBee技术的智能停车场系统研究

针对当前城市中普遍存在的停车难及停车场管理不规范的问题,提出了一种基于ZigBee技术的智能停车场管理系统。该系统采用125kHz激励器唤醒载有2.4GHz高频电子标签以及语音播报模块的车载单元,结合红外线反射性传感器和CC2530实现停车定位,并通过ZigBee无线通信网络实现车辆和控制中心的交互,从而实现无障碍智能停车场管理。本方法比传统的停车场管理方式更加准确、便捷、高效。     

基于混合天线的火车头车位监控系统

利用定向天线高增益、抗干扰能力强、通信距离远、方向性好和全向天线的覆盖范围广的优点,设计了结合两种天线的火车头车位监控系统.传感器节点以MSP430G2533单片机作为主控芯片,无线通信采用nRF905射频模块,GPS定位模块用于采集火车头的地理信息,并使用VB 6.0编写了监控软件,实现了对火车头车位的监控.测试结果表明,系统数据传输延迟小、丢包率低、运行稳定、测量准确,能够满足火车头车位监控的应用需求.     

基于无线传感器网络的车位管理研究

针对当前大部分停车场管理方法落后,无法提供方便、快捷、高效的停车服务的问题,设计了基于无线传感器网络的车位管理系统。该系统通过传感器检测车位的空闲信息,经汇聚节点传送给监测中心主机,以供停车场管理员统一管理。详细介绍了系统的总体架构,设计开发了传感器节点、汇聚节点和监测中心主机的软硬件模块,并讨论了传感器节点和汇聚节点节省电量的工作策略。系统使用结果表明,该系统的使用让停车场的管理更加智能、高效。     

基于A*算法的停车场路径引导设计

为提高停车场停车效率和选择最佳停车位,根据停车场的车位布局及车位使用状况,设计了泊车路径规划模型。把空闲车位抽象为二维坐标系的坐标点,分别计算其距离用户位置的曼哈顿距离,选取曼哈顿距离最小值的停车位为最优车位。选用改进的A*算法为停车路径规划算法,为进一步优化算法遍历过程,使之更加适用于停车场车位分布较分散的情况,以停车位对应路段为遍历节点进行路径搜索,并完成路径规划,结果表明:该方法有效地去除了冗余节点,提高了算法遍历速度。     

基于433 MHz频段的无线地磁车位检测传感器节点设计

针对现在存在的寻找车位难的问题,设计一种利用地磁传感器的基于433MHz频段的无线车位检测节点.该节点利用地磁传感器在有车和无车状态下的数据变化来检测车位状态;利用MSP430F5438和相应的门控管理电路达到低功耗的特性;利用433MHz通信模块,实现数据的无线传输.阐述了整个节点软件的主流程和车位检测的流程.利用实验验证了该车位检测节点和检测方法的有效性与合理性.