改进离散粒子群的异构无线传感器网络路由算法研究

异构无线传感器网络深受人们青睐,传感器节点能量的损失与路由算法密切相关,所以路由算法成为近年来无线传感器网络研究工作开展的主攻方向。本文结合改进的自适应离散粒子群算法,提出基于改进自适应离散粒子群算法的异构无线传感器网络路由算法,构建综合性目标函数及确定评价指标。仿真结果表明:改进算法由于在适值函数上充分考虑簇头节点能耗及簇间负载均衡因子,使得算法性能得以改良。     

WSN中动态自适应蚁群路由算法

路由问题是无线传感器网络的核心问题,采用动态自适应调整信息素的蚁群算法,克服了基本蚁群算法的搜索时间过长、易于陷于局部最优解等缺点;同时对无线传感器网络存在的节点能量、传输延时、网络生命周期等问题有明显的改善与提高;最后通过实验仿真证实了该算法的有效性.     

无线传感器网络的蚁群自组织算法

探测效能与能量节省的综合性能优化是无线传感器网络研究的一个热点问题.提出了一种分布式、自适应的无线传感器网络蚁群自组织算法,将无线传感器网络节点映射为情绪蚂蚁,通过蚁群间的协同对节点的唤醒概率进行群体智能优化,从而实现无线传感器网络自组织,并以定理的形式给出了性能指标和相关参数的设计方法.仿真表明,算法实现在唤醒较少节点的前提下,对目标保持了较好的探测能力.     

混合光无线传感网络节能路由算法优化

为解决混合光无线传感网络节点因自身能量耗尽而过早消亡的问题。结合改进的蚁群算法,对一般混合光无线传感网络节能路由算法进行优化。首先给出节能路由算法的假定条件,设置算法具体应用场景,然后构建混合光无线传感器网络通信能耗模型,最后从引入路径度量,改进前向蚂蚁和返回蚂蚁的信息素更新规则着手,提高传统蚁群算法收敛速度,以减少能量消耗,实现混合光无线传感网络节能路由算法优化。结果表明：与三种算法进行对比,所研究算法应用下,混合光无线传感网络节点消亡时间更晚,网络能量剩余更多,由此说明所研究算法能延长混合光无线传感网络使用寿命。     

具有能量和位置意识基于ACO的WSN路由算法

通过融合传感器节点的剩余能量和地理位置信息,设计一种具有传感器节点能量和地理位置意识的基于蚁群优化方法的无线传感器网络路由算法(ELACO);针对路由空洞现象,提出一种路由回退机制,提高了路由搜索成功率.仿真结果表明,ELACO算法具有很高的路由查寻成功率,能够更好地均衡传感器节点能量消耗,从而延长网络使用寿命.     

WSN中基于能量感知的最小跳数路由算法

无线传感器网络的拓扑往往由于节点死亡而发生变化。网络拓扑的重新构建加速了剩余传感器节点的死亡,缩短了网络的生存时间。针对无线传感器网络对网络生存时间的苛刻要求,提出了一种基于能量感知的最小跳数路由算法。建立路由时,该算法综合考虑了节点剩余能量和该节点潜在的转发能力。仿真结果显示,该算法在生存时间、存活节点数和吞吐量方面的性能要远优于LEACH算法和HEED算法。     

基于遗传算法和蚁群算法的LEACH改进协议

针对无线传感器网络低功耗自适应集簇分层(Low Energy Adaptive Clustering Hierarchy, LEACH)路由协议因能耗不均衡导致节点过早死亡的问题,提出了一种基于遗传算法和蚁群算法改进的LEACH路由协议。在分簇阶段,通过遗传算法选举合理的簇头节点并根据节点的分布划分簇群;在数据传输阶段,通过蚁群算法使簇头节点尽可能选择能量充足且距离较短的路径进行数据传输。仿真结果表明,与传统的分簇路由协议LEACH和LEACH-C相比,改进算法可以使网络的能量消耗更加均衡,并延长网络的生命周期。     

面向智慧园区的WSN路由优化算法

为解决智慧园区中无线传感器网络(WSN)的能耗不均衡问题,构建了路由代价函数,并提出了一种新的能耗均衡路由算法.该算法结合智慧园区中无线传感器网络的特点,综合考虑节点地理位置和剩余能量来构建路由代价函数.传感器节点通过选择其邻居节点中路由代价最小的节点进行数据转发.仿真结果表明,该算法可以有效节约网络能耗,同时延长了网络的生命周期.     

改进遗传算法优化无线传感器网络路由算法

为了有效延长无线传感器网络的生存时间,针对传感器节点能耗不均衡难题,提出一种改进遗传算法优化的无线传感器网络路由算法。首先对LEACH算法不足进行分析,然后构建簇头节点选择的目标函数,并将其作为遗传算法的搜索目标,最后通过遗传算法找到下一时刻簇头的候选节点,并针对遗传算法不足进行相应改进。采用仿真实验对算法的性能进行分析,结果表明,相对于其它无线传感器路由算法,本文算法可以保证无线传感器的节点能量均衡,延长了网络的生存时间。     

基于BP神经网络和蚁群的WSN分簇算法的研究

在研究经典低能量自适应分簇路由算法的基础上,提出基于BP神经网络和蚁群的无线传感器网络分簇路由算法。在分簇阶段将BP神经网络应用于每个分簇结构中,把采集的大量信息通过设计好的神经网络模型融合得到反映原始数据特征的少量数据信息。在数据传递阶段将蚁群算法应用到簇间路由机制中,寻找簇头到基站的最佳路径。将融合后的数据通过优化的路径传送到汇聚节点。仿真结果表明,该算法和LEACH算法相比,有效地均衡了网络的能量消耗,并延长了网络的生命周期。     

Preparation and Characterization of TaN ALD Precursors

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.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

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.     

Electronic Structure of Semiconductor Nanocrystals

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.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

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.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.