智能家居ZigBee网络的构建与路由优化

ZigBee网络技术是一项新兴的低成本、低功耗的短距离无线通信技术,在智能家居中有广阔的应用前景。介绍了智能家居中ZigBee的通讯协议和网络地址分配方法,并针对传统的AODVjr路由算法在路由过程中RREQ分组过量洪泛问题和Cluster-Tree算法只按父子关系选择路由问题,提出了一种改进路由算法。改进算法将AODVjr和Cluster-Tree算法相结合,引入邻居表,适当控制RREQ转发方向,并考虑节点最小剩余能量。仿真结果表明,改进算法可以减少路由开销,延长节点的生存时间,均衡网络负荷。     

基于簇树AODVjr的混合动态成簇路由算法北大核心

针对ZigBee无线传感器网络在移动过程中严重丢包和能量受限问题,通过分析簇算法、簇树(ClusterTree)与AODVjr混合算法,设计了一种基于ClusterTree+AODVjr协议的混合动态成簇路由算法。该算法采用动态成簇机制,能够使节点移动后及时响应拓扑变化,快速重建网络连接,减少丢包现象,提高网络有效分组递交率;同时利用减少RREQ(路由请求分组)的洪泛广播来降低能耗。利用网络仿真器NS2进行了仿真实验,结果表明与原ClusterTree+AODVjr算法相比,该改进算法可平均降低14%的能耗,提高8%的平均有效分组递交率。     

一种基于动态概率转发的AODV路由协议

在Ad hoc网络(自组织网络)的路由建立过程中,由于AODV(Ad hoc按需距离矢量)路由采用洪泛方式转发RREQ(路由请求)消息会产生很多不必要的重传,很可能引发广播风暴而影响网络性能。文章提出了一种基于动态概率转发RREQ消息的改进方案,该方案根据邻居节点的个数选择不同的概率转发RREQ消息。仿真结果表明,在网络节点较多且网络比较稠密的情况下,改进方案能有效减少网络端到端时延,提高网络吞吐量和分组投递率。     

一种能量平衡的无线体域网络AODV多播路由发现协议

在动态网络拓扑中,AODV协议通过数据源节点S泛洪广播RREQ消息请求到任意目标节点D的路由,而在无线体域网络中,只有一个sink目标节点,除最短跳数路由上的节点外,其他参与RREQ接收和转发的节点浪费了能量。提出了一种能量平衡的无线体域网络AODV多播路由发现协议,通过在节点广播的hello消息中增加到sink的最小跳数hops、到sink的下一跳节点next和节点本身是否具备转发能力isforward 3 个参数,只选择能到达sink节点的邻居节点参与转发RREQ消息,变广播为多播,有效地降低了路由发现的能量开销,并通过能量平衡延长了WBAN的使用寿命。性能分析与模拟实验表明,该协议在RREQ数量、数据传输率和能量消耗等方面优于相似协议EAAODV。     

ZigBee路由算法的改进

网络层的路由协议是ZigBee协议规范的研究重点之一,因为网络节点中节点的能量资源、计算能力和带宽都非常有限,路由算法优化与否对整个网络的性能有着至关重要的作用。从控制RREQ分组以及能量均衡的角度出发,对AODVjr算法提出了改进。通过仿真实验,将改进的算法与原AODVjr算法进行性能参数的比较分析,实验结果验证了改进后的算法的有效性。     

基于灰色关联的ZigBee网络混合路由算法

ZigBee网络混合路由算法(ZigBee Routing,ZBR)中将源节点和目的节点之间的最小跳数作为唯一的路由度量因素.但随着节点能量消耗以及节点的频繁移动,ZBR算法的这一特性会造成网络间歇性连接,从而导致网络性能下降.提出一种选择最优分组转发路径的ZigBee网络混合路由算法(Grey Relational Algorithm based ZBR,GRA-ZBR).GRA-ZBR算法在目的节点选择路径时引入灰色关联算法,综合考虑节点剩余能量、链路质量、节点剩余队列长度以及路径长度等因素.仿真结果表明,GRA-ZBR算法可以有效提高网络分组投递率,降低平均端到端时延.     

基于节点特性的LR-WPAN网络能量优化路由算法

针对ZigBee网络混合路由算法的不足,考虑低速无线个域网(LR-WPAN)网络的能耗问题,提出了一种基于ZBR路由协议的改进算法(F-ZBR).本算法通过定义最小路由能量值和控制路由请求分组(RREQ)的传输方向、跳数以及在RREQ分组中加入能量标志位等措施,降低网络的整体能耗.仿真结果表明,F-ZBR算法的分组投递率、网络可用节点比率和网络剩余能量都较ZBR有明显提高,从而可以延缓ZigBee网络中大量数据传输造成的RN+节点能量过度损耗而导致的网络瘫痪等问题的发生,延长网络生命周期.     

基于灰色关联的ZigBee网络混合路由算法研究

ZigBee网络混合路由算法(ZigBee Routing,ZBR)中将源目的节点之间的最小跳数作为唯一的路由度量因素。但随着节点能量消耗以及节点的频繁移动,ZBR算法的这一特性会造成网络间歇性连接,从而导致网络性能下降。本文提出一种选择最优分组转发路径的ZigBee网络混合路由算法—GRA-ZBR算法。GRA-ZBR算法在目的节点选择路径时引入灰色关联算法,综合考虑节点剩余能量、链路质量、节点剩余队列长度、以及路径长度等因素。仿真结果表明：GRA-ZBR算法可以有效提高网络分组投递率,降低平均端到端时延。     

ZigBee路由协议算法的研究

通过对ZigBee中的Cluster-Tree算法以及对AODVjr中的路由发现进行研究,在Cluster-Tree邻居表的基础上提出捷径路由,从该节点周围的邻居节点中找出可以用少量跳数即可到达目的节点。此后通过路由代价函数,计算通过Cluster-Tree改进算法中找到节点路径的能量使用代价,选择可靠性较高的路径,从而可以延长网络生存周期和降低能耗。最后通过实例,验证了算法改进的可行性。     

基于限制广播域和节点剩余能量的按需路由算法研究

按需路由协议AODV的路由发现使用洪泛方式的扩散法,导致网络超负荷运行和拥塞,而且在选择转发路由时,总是选择最少跳数的路由,造成无线传感网络中节点能量不均,减少网络寿命.本文提出了AODV-DE算法,该算法引入广播域的概念,限制RREQ分组的转发范围,同时避免使用剩余能量低的节点转发数据分组,选择路由路径时选择总剩余能量最多的路径进行信息的传送.仿真结果表明,AODV-DE协议在路由开销、网络寿命和端到端的延迟这三个方面表现出了优势.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first