SDN中一种基于多级流表的功能组合方法

软件定义网络（Software-Defined Network,SDN）中的网络应用往往需要实现多种功能以满足上层业务需求,而如何对运行在控制器上的功能模块进行编排以完成数据包的多功能组合处理是一个仍待解决的问题.针对该问题,本文提出基于多级流表的功能并行和串行组合方案;其次,提出与任意多级流表交换机相适配的功能组合算法;最后,在Ryu控制器中添加功能组合模块并基于NetFPGA-10G节点完成了功能组合的原型实现.仿真实验与结果表明,与现有功能组合方案相比,所提功能组合方法降低了流处理时延及表项存储开销.     

基于非接触式电流传感器的电力系统拓扑识别方法

正确的拓扑结构识别对于电力系统在状态估计及故障定位等方面至关重要。为了解决这一问题,本文提出了一种新的拓扑识别方法,该方法基于非接触式线路电流传感器的测量值,以及节点功率注入的伪测量值。首先将拓扑识别问题表述为混合整数非线性规划问题,然后采用重构方法来处理非线性问题,将其转化为混合整数线性规划形式。此外,还对非接触式线路电流传感器的规划提出了建议,以确保拓扑识别方法的性能。对提出的拓扑识别方法在33节点测试系统以及某某地的真实线路的上进行了测试。该方法能够识别所有可能的拓扑,包括放射型、环型和孤岛,从而扩展了拓扑识别在电力系统运行方面的应用。     

一种基于Viterbi算法的虚拟网络功能自适应部署方法

为了应对移动数据流量的爆炸性增长,5G移动通信网将引入新型的架构设计。软件定义网络和网络功能虚拟化是网络转型的关键技术,将驱动移动通信网络架构的创新,服务链虚拟网络功能的部署是网络虚拟化研究中亟待解决的问题。该文针对已有部署方法未考虑服务链中虚拟网络功能间顺序约束和移动业务特点的问题,提出一种基于Viterbi算法的虚拟网络功能自适应部署方法。该方法实时感知底层节点的资源变化并动态调整拓扑结构,采用隐马尔科夫模型描述满足资源约束的可用的底层网络节点拓扑信息,基于Viterbi算法在候选节点中选择时延最短的服务路径。实验表明,与其它的虚拟网络功能部署方法相比,该方法降低了服务链的服务处理时间,并提高了服务链的请求接受率和底层资源的成本效率。     

多约束的战术互联网拓扑模型研究

为了解决战术互联网拓扑模型生成问题,分析了现有的拓扑构建方法的不足,从拓扑模型建立、约束条件、拓扑分析等几方面对战术互联网网络模型进行了研究.通过构建多约束下的节点模型、边模型,进而构建网络拓扑模型,并从节点度、平均路径长度、网络效率等方面对拓扑模型进行了特性分析.仿真结果表明,提出的多约束的战术互联网拓扑模型生成方法能够很好地满足新一代战术互联网的拓扑结构.     

分布式声传感器阵列校准方法综述

分布式声传感器阵列在军事侦察、公共安全监控和人机交互等领域应用广泛.但时钟异步、频率响应失配和节点位置未知问题严重影响后续基于分布式声传感器阵列的语音处理算法的性能,因此近年来学者们热衷于研究校准这三类阵列失配问题的方法.首先,本文介绍了导致分布式声传感器网络各类失配问题的原因和三类问题解决的先后顺序.然后,将现有的解决三类问题的方法进行了综述.其中,时钟同步方法主要包括基于时间戳交换和短时傅里叶变换域线性相位漂移的方法,频率响应校准方法主要包括基于声源导向矢量和自适应滤波器的方法,节点位置/位姿校准方法则主要包括基于节点间几何构型和深度学习的方法.最后,给出了本领域未来研究的方向.     

双归属环形网络拓扑规划算法设计

本文研究了一种高效的双归属环形网络拓扑规划算法,提出了在满环与非满环间调整节点的启发式搜索算法,当节点数在1 500个以内时,本算法都能很快求解,而现有算法通常只能处理几百个节点的中等规模网络.本文首先给出了相关数学模型,然后详述了初始拓扑生成过程及采用的启发式优化算法.最后通过将CPLEX规划结果、人工规划结果和算法规划进行比对,验证算法性能.     

无线传感器网络中基于EBS的高效安全的群组密钥管理方案

为了保证无线传感器网络(WSN)群组通信的安全性,设计了一种基于EBS的群组密钥管理方案.提出方案首先通过合并链状簇和星型簇简化无线传感器网络的拓扑结构,然后通过增加网络被捕获时所需入侵节点的数量来防止攻击者通过少量共谋节点得到所有管理密钥,之后利用图染色算法对分配密钥组合的节点进行排序,并依据海明距离和EBS方法对网络中的传感器节点进行管理密钥分配.在此基础上给出了对传感器节点的加入和离开事件进行处理的方法.在有效性和性能分析阶段,首先通过2个实验分别对提出方案中共谋攻击的可能性和入侵节点数量对网络抵抗共谋攻击能力的影响进行分析,实验结果表明提出方案增强了WSN抵抗共谋攻击的能力;然后对提出方案和SHELL在加入事件和离开事件时的系统代价进行比较,结果表明提出方案所需的密钥更新消息数量和传感器节点存储量均小于SHELL方案.     

基于无线传感器网络的农业环境监测系统

针对当前农业环境在线监测的需要,提出了一种利用具有自组织特性的无线传感器网络(wireless sensor networks,WSN)对温度、土地湿度和土壤的PH值等环境变量进行在线监测的方法.该方法采用了对等式网络体系结构、低功耗微小网络节点、基于拓扑树的网络初始化配置算法.实验测试表明节点能够有效地采集和处理数据,并可以在节点间成功地进行通信.     

具有QoS保证的分布式服务组合策略

现有的服务组合方法多是获取候选服务节点的信息,在集中式组合引擎上搜索路径.这种集中式方法不仅具有单点失效、可扩展性差等缺点,而且候选服务的QoS没有保证,服务搜索空间过大,组合效率较低.文章提出了一种分布式的服务组合方法(BDDSC),将分散在网络中性能有保证的服务节点构建成服务覆盖网络,使各个节点协作执行进行动态服务...     

一种新型的基于节点类型识别机制的P2P网络拓扑构造协议

现有P2P网络拓扑构造协议大多是基于节点历史行为来决定拓扑的构造方式,在面对P2P节点复杂多变的行为时无法实时地保证拓扑的有效性。该文首先利用博弈论针对不同类型节点的交互行为及收益建立博弈模型。在此基础上,提出了基于节点类型跟踪识别机制的拓扑构造协议TATP。仿真实验表明,TATP协议即使在恶劣的P2P网络环境下也能够让善意节点开始聚集,将恶意节点排斥到网络边缘,使得P2P网络拓扑具有更好的有效性和安全性,同时协议的网络开销较小。     

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.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

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.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

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.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

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.     

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.