基于双簇头非均匀分簇的LEACH协议的改进

在无线传感器网络中的LEACH协议是一种自适应聚类路由算法．由于LEACH协议存在着无法控制簇首在网络中的分布位置、簇首选择方式限制条件不够等缺点导致能量消耗太大．基于簇头能量限制和双簇头路由方式,对LEACH协议进行了改进,设计了一种降低能耗的双簇头非均匀分簇路由协议．双簇头非均匀分簇路由协议采用NS2进行网络仿真实验,通过仿真结果的分析以及与LEACH协议的对比,证明双簇头非均匀分簇路由协议有效提高了网络能耗的均衡性．     

UCRP—一种能量有效的WSN非均匀分簇路由协议

提出了一种新的能量有效的非均匀分簇路由协议—UCRP.根据距离基站的远近将网络分为大小不同的簇;簇内数据传输根据簇范围的大小采用单跳或多跳;簇间数据传输构建多跳路由,簇首选择下一跳节点时将能量与最小跳数路由算法相结合;最后在能量有效的前提下对LEACH协议易受到HELLO flooding攻击提出了安全设想.仿真结果表明:该协议能够有效地均衡簇首和全网能耗,延长网络生存时间.     

无线传感器网络能量均衡分簇路由协议

LEACH是无线传感器网络(Wireless Sensor Network,WSN)中一种经典的分层式路由协议,在此基础上通过对LEACH成簇算法及簇间路由的改进,提出了一种新的均衡能量消耗分簇路由协议。该协议在无线传感器网络成簇过程中充分考虑了传感器节点的能量状态,同时簇首向基站的通信采用基于能量的簇间路由。理论分析及仿真结果表明,改进的协议能够均衡传感器节点的能量消耗,有效地延长网络寿命。     

基于数据融合的无线传感器网络路由算法

在分簇协议LEACH和链状协议PEGASIS的基础上,提出一种新的基于数据融合的分簇路由算法.簇首节点采用多跳方式传输数据,并根据周围节点的密集程度构造不同大小的簇;簇内节点计算上行和下行节点构造数据融合树,采用时分复用调度算法进行多跳路由.NS2仿真结果表明该路由算法均衡了各个节点的能量消耗,延长了网络存活时间,并降低了网络延迟.     

基于最小生成树的LEACH协议改进

LEACH(Low Energy Adaptive Clustering Hierarchy)是一种被广泛应用于无线传感网络的路由协议.本文针对LEACH协议中,远距离节点作为簇首时能量消耗过多的缺点,提出了一种改进的无线传感网络路由协议.多跳传输LEACH改进协议在节点选出簇首之后,采用最小生成树中Prim算法,在簇首与基站间采用多跳传输.为克服多跳传输时距基站第一跳的簇首能量消耗较多的缺点,阈值需要采用节点距基站的距离和节点距簇首的平均距离来调整,已达到平衡节点能量消耗的目的.仿真结果表明,改进的算法可减少和均衡能量消耗,提高能量的使用,以及延长整个网络寿命方面具有很大的优势.     

基于环形搜索的WSN簇间最优路由选择

为了解决LEACH协议中由单跳路由算法造成的节点能量消耗不均衡的问题,首先,计算分析得出簇间多跳的最优跳数,得到簇头节点到基站的一条理想路径;然后,提出一种环形搜索方法去寻找与理想路径最接近的最优路径;最后,提出了簇头到基站的多跳路由算法。仿真实验结果表明,簇头到基站的多跳路由算法较LEACH协议在均衡节点能量消耗和延长网络生命时间方面的性能有明显的提高。     

无线传感器网络功率路由算法研究

无线传感器网络的应用越来越广泛,主要是军事、工业、医疗等方面。然而无线传感器网络具有节点能量、存储和计算能力非常有限等特点,文中在传统的LEACH（低功耗自适应集簇分层型）协议的基础上进行了改进,并提出了一种新的无线传感器网络路由算法LEACH-N。新算法沿用了LEACH协议簇的结构,在簇头选择方法上基于传统DCHS算法的簇头选择算法,簇内成员与簇头之间直接通信,簇头与基站之间轮流进行单跳和多跳通信;多跳通信则是采用一种改进的MTE（最小传输能量）路由算法。通过NS2仿真软件对LEACH-N协议与LEACH协议分别进行了性能测试。实验结果表明,相比LEACH协议,LEACH—N协议系统能耗低、网络生命周期长,且具有更好的规模可扩展性。     

基于二跳信息的分簇算法

对于低功耗自组织的无线传感器网络,其路由协议和拓扑控制受到了很多学者的关注,且已成为国际的研究热点.在分析了LEACH,FSR算法的基础上,提出了一种基于二跳信息的分簇算法,以有效提高网络生命期.着重对算法的设计思想和工作过程,包括簇首选择与簇建立,簇成员通信等进行了分析和论述.仿真结果表明本文中的算法对于LEALCH能有效提高网络生命期.     

WSN中一种基于LEACH的协同通信算法的研究

近年来,协同通信在无线传感器网络中取得了很大的应用,重点分析和研究了一种基于低功耗自适应集簇分层型协议（LEACH）的协同通信算法;在该算法中,通过选择合适的协同节点来发送数据可以有效的减少簇头节点的能量消耗,并且与多跳传输相比,又节省了路由更新耗费的能量,实验仿真证明基于LEACH的协同算法（LEACH-COOP）在能量消耗上与LEACH和基于LEACH的簇头多跳算法（LEACH-MH）相比表现出了更优的性能。     

一种基于LEACH路由协议的改进算法

无线传感器网络的生存时间受传感器节点软硬件条件的限制,改进传感器网络路由协议是延长网络生存时间的有效途径。LEACH协议是最早提出的经典分层路由协议,文中基于LEACH协议提出改进,应用K-medoids算法改进LEACH协议的簇首分簇机制,并通过Matlab仿真实验,证实了改进后的LEACH算法在均衡化网络能耗,延长网络的生命周期方面具有优越性。     

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.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

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.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.