共查询到20条相似文献,搜索用时 62 毫秒
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路由均衡过程存在负载开销,导致路由分配风险概率增加,提出基于SVM的电力通信网络路由均衡方法。构建路由均衡模型,通过能量函数分配网络业务路由,基于粒子群优化算法改进最小支持向量机的路由算法,求解均衡模型;通过最小支持向量机估算网络节点剩余能量,选用负载开销最小的路径路由数据,实现电力通信网络全局路由均衡分配。实验结果表明:该方法可均衡电力通信网络中存在的风险,且噪声大小对电力通信网络覆盖率、节点平均剩余能量以及业务中断影响不明显,在均衡电力通信网络业务方面具有可靠性与有效性。 相似文献
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无线传感器网络所具有的集中式数据收集、多跳数据传输、多对一流量模式容易导致严重的包碰撞、网络拥塞,包丢失,同样也会导致能量消耗的热点出现,使某些节点甚至整个网络过早死亡.文中提出一种能耗均衡的数据收集算法,此算法按节点离基站的距离进行分层,根据中间节点的能量参数和通信开销建立到基站的多径路由,在数据收集过程中除了利用具有最小能耗的最优路径外还偶尔使用一些次优路径;为进一步减少节点能耗,算法还采用了数据聚合机制.分析和仿真结果表明,算法在很大程度上均衡了节点间能耗并延长了网络寿命. 相似文献
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基于跨层设计的无线传感器网络节能双向梯度路由算法 总被引:1,自引:0,他引:1
针对现有无线传感器网络梯度路由算法在下行路由创建过程和能量更新机制中存在冗余控制开销的问题,该文提出一种采用跨层和功率控制机制,具有节能功能的双向梯度路由算法(Cross-layer Energy-efficient Bidirectional Routing, CEBR):无需使用专门的控制分组,采用源路由方式以较小开销建立从Sink节点通往传感器节点的下行路由;通过跨层信息共享,定期采集节点剩余能量信息并按需发布;设计使用含跳数和节点剩余能量的合成路由度量标准,减少节点能量和网络带宽消耗的同时均衡节点能耗;结合RSSI(Received Signal Strength Indication)测距实现节点发射功率控制从而在数据及查询分组发送过程中节约节点能量。理论分析表明了CEBR的有效性;仿真结果显示:与现有的典型相关算法相比,CEBR能够在建立双向梯度路由的前提下,至少降低34.5%的归一化控制开销和27.12%的数据分组平均能耗,并使网络生存期延长18.98%以上。 相似文献
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在实际的无线传感器网络中,由于路由空洞的存在,采用边缘转发机制的地理路由算法容易使空洞边缘的节点由于负载较重,能量快速消耗从而过早的死亡,导致空洞进一步的扩大.为了使网络负载更加均衡,延长网络生命周期,提出了一种基于能量信号机制的地理路由算法SIENGR .SIENGR将节点的初始能量划分3个能量区间,并用能量信号来标识节点的剩余能量所处的能量区间.SIENGR算法的边缘转发机制结合节点的能量信号,利用空洞边界节点的所有平面邻居节点来轮流承担边缘转发的数据量,使产生的路由能够根据节点能耗的情况,自适应地避开空洞边缘能量较少的热区节点,均衡热区附近节点的能量消耗,防止空洞扩大.仿真结果验证了SIENGR算法在网络生命周期、网络能耗均衡、数据包到达率等指标上的性能. 相似文献
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基于泛洪约束的MANET按需组播路由协议 总被引:2,自引:0,他引:2
降低路由控制开销是MANET网络组播路由协议节省节点能量,提高带宽利用率的关键因素之一。本文研究了组播路径近邻节点对路由维护的作用以及链路的连通性,分别提出了一个新的泛k-洪约束算法和一个混合泛洪模式。基于泛k-洪约束算法和混合泛洪模式,提出一个新的按需组播路由协议ODMRP-CF,ODMRP-CF协议通过选择k-路由近邻节点转发泛洪分组来提高泛洪效率。ODMRP-CF协议不仅保持了ODMRP协议所具有的简单,对节点移动鲁棒性好的优点,而且有效地降低了ODMRP-CF协议的控制开销。 相似文献
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作为能量有效、基于链状结构的路由协议的典型代表,PEGASIS协议存在三个方面的不足,一是链的生成算法会导致相邻节点间产生长链;二是链头节点选取方法会导致节点间能量消耗不均衡;三是链头节点重选频率增加了通信开销.本文基于PEGASIS提出了一种新算法,新算法通过引入距离门限避免相邻节点间产生长链;通过综合考虑节点剩余能量以及节点到基站的距离来选取链头节点;通过降低链头节点重选频率来节省通信开销.分析和仿真结果表明,在未增加算法复杂度的情况下,新算法在平衡节点能耗和延长网络寿命方面比PEGASIS算法具有更优越的性能. 相似文献
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Michael Reilly 《半导体技术》2004,29(12)
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. 相似文献
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Thomas M.Trexler 《半导体技术》2004,29(5)
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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Qi-jiang Ran Pei-de Han Yu-jun Quan Li-peng Gao Fan-ping Zeng Chun-hua Zhao 《光电子快报》2008,4(4):239-242
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. 相似文献
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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. 相似文献
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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. 相似文献
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It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output(MIMO) communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory. 相似文献
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《中国通信》2014,(7)
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 相似文献