ZigBee无线传感器网络的地址扩展机制

目前无线传感器网络的地址分配机制为了支持组成几百个以上节点的大规模无线传感器而具有缺点。WSN相关标准化团体ZigBeeAllance提出的分布式地址分配机制是根据深度数分开16bit地址段为一定大小的部分。但这方式是按初期设定一律分配地址,所以在网络的扩张、有效率的地址利用方面还有限制。本文提出为了有效率利用据初期设定剩下的16bit地址空间余裕地址的方法与其路由选择方法,并提示它的模拟分析结果。     

基于ZigBee 的消防救灾无线传感器网络

由于救灾现场情况的多变特性,根据消防救灾的工作需要,设计了一种基于ZigBee的传感器网路.完成了传感器网络中监控中心和各个节点的设计,设计并编写了软件,实现了所需要的功能.最后进行实验检测了在不同通信距离段的通信效果和RSSI的值,实验证明该装置通信效果较为良好,室内的穿墙距离可达100~150 m,室外可达300 m.并且不同距离RSSI的实际值和实验采用的理论模型比较接近.该装置具有一定的实用价值.     

基于分段的ZigBee网络按需可扩展地址分配算法

提出基于分段的按需可扩展地址分配算法,按照预设的地址量对16bit地址空间进行分段,当路由节点子地址空间不足时对其逐段扩展,使更多节点获得地址;同时改进现有树路由协议使之能够兼容扩展的地址.理论和仿真分析表明所提算法的地址分配成功率等性能优于DAAM和它的改进方案SLAR.     

基于ZigBee与Android的城乡智能公交系统

针对城乡公交发展过程中存在的智能化程度低下、管理不便、乘客体验差等问题,文中通过对Zig Bee无线传感网络和Android平台在城乡智能公交中的应用分析,设计了适用于城乡间的智能公交系统。该系统通过Zig Bee与移动设备获取公交车实时位置信息及相应的车辆信息。司机通过车载Android设备掌控车内的信息,公交辖区经理掌控所有车辆运行情况。实际应用测试与分析表明,该系统能提供公交系统的准确定位、自动报站等功能,实现了城市公交系统的智能化管理与服务。     

基于地理位置的无线传感器网络IPv6地址配置

采用全IP互联方式,提出以数据为中心,按地理位置信息实现无线传感器网络(Wireless Sensor Networt,WSN)IPv6地址配置的方案.此方案将无线传感器网络栅格化,在每一个网格内头节点采用无状态地址自动配置方法为普通节点分配IPv6地址,各个网格的节点地址配置过程可同时进行.最后通过仿真分析,验证了此方案的有效性.     

一种面向Portal认证的IPv6可信地址分配机制

随着网络规模的增长,对网络进行精细化管控变得尤为重要。在下一代互联网中将用户可信身份嵌入 IPv6 地址后缀形成可信地址,能够进一步提高网络行为的可追溯性。目前已有研究基于 Portal 认证配合DHCPv6将用户的身份信息嵌入用户终端的IPv6地址中,但是为了分配可信地址而改动的DHCPv6过程造成了机制对用户终端不透明,无法大规模部署。提出了一种面向Portal认证的IPv6可信地址分配机制,通过服务器信令交互配合软件定义网络（SDN）技术实现IPv6可信地址的间接分配,而且与地址分配方式无关。最后,实现了一个原型系统并在江苏南京电信现网机房评估了其可行性和性能,结果表明此机制在对终端透明的情况下仅带来很少的额外开销。     

基于Z—Stack协议的无线传感器网络节点研究

为了简化Zigbee开发,文中利用TI公司推出的Z—Stack协议栈及其对应的芯片,通过组建星形、树形和网状等无线网络,并在节点外设中添加传感器,从而得出了简单快捷地组建无线传感器网络方法。     

紫蜂网络中的时间同步

FTSP时间同步算法是一种网络级的时间同步技术。该算法选取一主节点,作为一个参考时间源来提供服务。采用了发送单个广播消息的思想。具体实现如下:在完成同步字节的发送后,给时间包加盖时间戳,完成包的发送。接收节点记录同步字节到达的时间,并计算位偏移。在收到完整消息后,计算位偏移产生的延迟。然后利用接收节点与发送节点的时间偏移量来调整本地时间以达到与发送节点的同步。     

基于ZigBee的无线传感器网络研究

为了验证ZigBee协议的有效性,叙述了新型无线ZigBee通信技术,介绍ZigBee协议的结构和特点,基于ZigBee协议的无线网络设备以及网络拓扑结构;ZigBee标准协议栈结构及数据在协议栈内部的传输机制。以两个网络设备成网为例,详细给出了ZigBee设备形成网络时,各个设备的工作状态、设备之间网络连接过程以及数据帧的发送过程。最后,通过Microchip公司的ZigBee实验平台验证了ZigBee无线星型组网,实验证明,ZigBee技术是有效的无线传感器网络组网技术。     

AdHoc网络中的地址自动配置和节点ID分配机制

对AdHoc络的地址自动配置问题进行了阐述,说明了现有网络地址配置机制面临的问题和挑战;然后从IPv4和IPv6两个层次分析了AdHoc网络的地址自动配置机制,尤其是IPv6的无状态地址自动配置机制;对AdHoc网络中的节点ID分配机制进行了探讨。     

Efficient distributed address assignment algorithm based on topology maintenance in ZigBee networks

Adopting the borrowed address algorithm can decrease the orphan nodes in ZigBee networks that use distributed address assignment mechanism （DAAM）. The existing borrowed address algorithms can increase the success rate of address assignment, but they have defects such as greater cost of overhead and time in founding network caused by breaking topology. To solve such problems, we propose an more efficient distributed borrowed address assignment algorithm based on topology maintenance （A2BTM） that has a topology maintenance function. It borrows address firstly from the offspring nodes in the same branch for the orphan nodes and replies distributed the request of the borrowed address message immediately, to maintain the network topology and decrease the overhead and time spent on the mechanism of borrowed address. Theoretical and simulation analyses manifest that AZBTM algorithm outperforms DAAM and its improved algorithms in terms of the overhead and time spent in founding network, on the premise of keeping a higher success rate of address assignment. Furthermore, A2BTM can lessen the influence from detour phenomenon efficiently.     

A distributed protocol for dynamic address assignment in mobile ad hoc networks

A Mobile Ad hoc NETwork (MANET) is a group of mobile nodes that form a multihop wireless network. The topology of the network can change randomly due to unpredictable mobility of nodes and propagation characteristics. Previously, it was assumed that the nodes in the network were assigned IP addresses a priori. This may not be feasible as nodes can enter and leave the network dynamically. A dynamic IP address assignment protocol like DHCP requires centralized servers that may not be present in MANETs. Hence, we propose a distributed protocol for dynamic IP address assignment to nodes in MANETs. The proposed solution guarantees unique IP address assignment under a variety of network conditions including message losses, network partitioning and merging. Simulation results show that the protocol incurs low latency and communication overhead for an IP address assignment.     

CRL分发机制改进研究

本文介绍了几种CRL分发机制,指出这些机制的优缺点,在此基础上提出了分段式 重叠发布增量CRL证书撤销机制,并进了性能分析比较。该机制能有效地分散CRL库的峰值请 求率和平均负荷,减小信任方所需下载的CRL大小,改善了时间碎片问题和可扩展性问题。     

Module replication and assignment for real-time distributed processing systems

Response time is an important design criterion for real-time systems. A new analytic model is developed to estimate task response time. It considers such factors as interprocessor communication, module precedence relationship, module scheduling, interconnection network delay, and assignment of modules and files to computers. Since module assignment as well as its replication have great impact on task response time, a new algorithm is developed to iteratively search for module assignments and replications that reduce task response time. An objective function is introduced that is based on the sum of task response time and delay penalty for the violations of thread response time requirements. With this objective function, good module allocations and replications, which minimize task response time and yet satisfy the thread response time requirements, can be determined by the proposed algorithm. To validate the algorithm, we compare the assignments generated by the algorithm for some sample distributed systems to the optimal module assignments obtained from exhaustive search. It shows that with a very small number of initial module assignments, our algorithm is able to generate the optimal or close-to-optimal assignments. The algorithm is also applied to a real-time distributed system for space defense applications where exhaustive search for the optimal assignment is not feasible. The generated module assignments (with replications) satisfy the specified thread response times, and compare closely with the simulation results. A series of experiments is also performed to characterize the behavior of the algorithm. In conclusion, the algorithm can serve as a valuable tool for assigning modules with replications for distributed systems.     

A scalable distributed dynamic address allocation protocol for ad-hoc networks

Dynamic address allocation is an essential part in effective configuration and maintenance of a mobile ad-hoc network (MANET). In this paper, we present a new distributed dynamic address allocation protocol minimizing address allocation latency and communication overhead. Through analytic evaluation and experimental measurements, we show that scalability and faster recovery from failures can be achieved by dynamic address allocation. The dynamic address assignment protocol presented here requires a low memory footprint while supporting unicast, broadcast and multicast communication. A performance analysis of the proposed address allocation protocol is given in terms of address allocation latency and communication overhead. Node and Network mobility is addressed from the point of dynamic address management. The dynamic address allocation protocol is implemented on a TinyOS platform over a cluster tree network.     

基于SOA的分布式光网络路由分配策略

将面向服务体系架构技术(SOA)应用于分布式光网络,提出一种面向服务的路由分配策略,实现不同域的资源共享.介绍了基于SOA的分布式光网络的体系结构,设计了路由的功能模型,给出了分布式路由的分配算法和实现算法的并行信令机制.通过仿真实验,将路由分配策略与传统的先路由后信令(FRLS)的路由分配策略进行了对比.     

SSD中一种地址映射算法研究

SSD中地址映射方式有很多种,常用的有三种：页映射、块映射和混合映射。页映射性能好,但是映射表占用空间大;块映射的映射表占用空间小,但是性能差。本文研究了一种通过算法给定的阀值来判定使用页映射还是混合映射,这样动态的转化使系统映射速度快,空间利用率高,同时也降低了系统资源的浪费和映射表的更新频繁等问题。     

基于ZigBee无线定位的智能车研究

介绍了单片机操作系统、C语言技术和GSM模块结合使用完成智能家居系统的设计与实现.主要实现三大功能:监控室内温度、防盗和检测室内可燃气以及烟雾.实践证明,本系统成本低,操作方便,并且达到了预期的稳定性和可靠性.