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1.
无线ad-hoc网络部署在非人为控制的外部环境中,采用电池供电.在这种应用环境中,如何通过合理的路由协议设计降低能量开销、提高网络的生存时间是近年来研究的热点.文章提出一种结合链路质量与能效的跨层路由协议.在路由建立阶段综合考虑链路质量、发送数据包的能耗和节点剩余能量来建立路由.通过在路由维护阶段对链路质量和节点剩余能量进行检测,预测路由中断的发生,并进行本地修复.通过在IEEE 802.15.4 Matlab模拟器下进行仿真,验证了该协议能够有效地提高网络的生存时间、数据投递率及AODV协议的性能和稳定性.  相似文献   

2.
无线传感网络由于受能量和通信能力的限制,为了保证感知数据的有效送达,路由方法(协议)的设计显得尤为关键.本文提出了一种基于前向感知因子的能量均衡路由协议FAF-EBRP,它通过感知链路权重和前向区域内的能量密度来决定下一跳节点,并设计了相应的局部拓扑自发重构机制.通过实验对FAF-EBRP和LEACH、EEUC两个典型路由方法(协议)进行了比较,结果表明,FAF-EBRP能使无线传感网络表现出更好的能量均衡性和更长的有效工作时间.  相似文献   

3.
链路可靠的无线传感器网络组播路由协议   总被引:2,自引:0,他引:2       下载免费PDF全文
宋震  周贤伟  林亮 《电子学报》2008,36(1):64-69
在无线传感器网络实际应用中,组播正在发挥着越来越重要的作用.但由于能量等多方面的因素,使得为无线传感器网络设计一个有效的组播路由是非常困难的.针对无线传感器网络中节点的能量限制,通过寻求节点间最短路径,提出一种能量有效的链路可靠组播路由协议(RLMR).该协议充分考虑到网络中节点的能耗因素和两节点间的链路可靠性等,通过对这两个因素的综合考虑,让能量较多并且以发送节点更靠近的节点承担更多传输任务的方式,为数据流优化路由选择,均衡无线传感器网络节点的能量消耗,以延长网络的生存时间.仿真结果证明了RLMR的有效性和可靠性.  相似文献   

4.
冯彬 《电讯技术》2012,52(6):992-996
针对无线数据链网络,提出了一种新型的基于分层结构的IP路由算法模型,满足至少3种异构数据链网络的集成要求.仿真结果表明,该模型可有效支撑基于链路带宽、传输时延、链路质量等多种QoS的路由算法设计,为无线数据链网络层IP路由协议和算法设计提供了理论框架和实现指导.  相似文献   

5.
无线HART(Highway Addressable Remote Transducer)是当前工业无线传感器网络中应用最为广泛的协议,但无线HART没有提供动态路由机制以满足对工业无线网络应用至关重要的稳定性和鲁棒性。该文在无线HART协议基础上,提出一个基于收集树协议的可应用于工业无线传感器网络的动态路由机制。它占用时分多址(TDMA)超帧中的前几个时间片来产生和维护网络拓扑。通过仿真实验从3个方面对该动态路由机制进行了评估:拓扑生成时间,链路质量及网络拓扑的稳定性。仿真和评估结果表明该动态路由机制可以在基于TDMA的工业无线传感器网络中应用。  相似文献   

6.
在无线Ad Hoc网络中,为了提高链路质量和通信的稳定性,提出一种基于AODV路由协议的链路中断预测和最短路径修复机制(LIFSR-AODV).通过检测网络中的链接质量,预测和避免链路中断的发生,降低了本地修复过程中控制包的开销和传输延迟.同时,在修复过程中能够通过删除链路中的多余节点来缩短路径长度.通过在IEEE 802.15.4 Matlab模拟器下仿真,验证此路由机制能够提高AODV路由协议的性能和链路的稳定性.  相似文献   

7.
无线传感器网络路由中的能量预测及算法实现   总被引:3,自引:0,他引:3  
基于无线传感器网络中路由协议高效合理利用能量的要求,提出一种基于剩余能量预测的地理位置路由(EPGR,energy prediction and geographical routing)算法。算法通过建立传感器网络节点运作模型,及相邻节点剩余能量预测机制,优化路由选择。仿真和分析表明,EPGR算法能够有效地优化数据传输路径,均衡传感器网络节点的能量消耗,延长网络寿命。  相似文献   

8.
本文对无线传感器网络中广泛使用的RPL路由协议进行了深入的分析研究,指出其使用单一的链路质量作为路由度量标准存在的问题。通过引入能耗模型,计算节点的电量消耗情况,并与链路质量加权结合,提出了一种能量感知路由度量标准。使得传感器节点在进行路由选择时不仅能够兼顾链路质量,同时能够避免个别节点负载过重的问题,在节点之间取得了能耗情况的相对平衡。  相似文献   

9.
对于复杂的室外环境,无线传感器网络如何建立可靠的路由,并尽可能延长全网寿命是一个关键问题.在分析总结现有无线Ad Hoe网络路由协议的优缺点的基础上,提出了一种基于能量与链路稳定性感知的多度量的按需路由协议ELSA-AODV.ELSA-AODV协议是AODV协议的增强与扩展,在保证路由可靠性与稳定性的同时,平衡全网的通信负荷与能量,大大延长了全网的工作寿命.通过仿真实验,验证了ELSA-AODV的有效性.  相似文献   

10.
一种适用于非对称链路的Ad Hoc网络路由协议   总被引:3,自引:0,他引:3  
提出了一种适用于非对称链路的Ad Hoc网络路由协议。该协议是一种基于路由池的反应式路由协议,当源节点与目标节点有数据交换时,通过路由发现过程分别在源节点和目标节点构建数据路由池和应答路由池,数据的发送和应答路径随机地从相应路由池中选取,并在数据的交换的过程中动态地更新和维护路由池。仿真结果表明该协议适用于普遍存在非对称链路的无线移动Ad Hoc网络。  相似文献   

11.
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   

12.
High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET > PDMAT > TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.  相似文献   

13.
In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal (200) (2d = 0.4027 nm) is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line(w), the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line(x), the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines(y), the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line(z) in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line(q) in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution(λ/△ 2) is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.  相似文献   

14.
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   

15.
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   

16.
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   

17.
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   

18.
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   

19.
This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.  相似文献   

20.
An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.  相似文献   

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