信息中心网络中基于节点缓存命中贡献率的缓存替换方案

信息中心网络(CCN)是一种全新的网络架构,其显著的特点是处处缓存,合理的内容缓存部署能够显著提高网络传输效率.缓存替换策略是缓存管理中的重要组成部分,合理地进行缓存内容的替换,成为影响网络整体性能的关键.考虑到内容自身的特性,设计了一种基于节点缓存命中贡献率的贪婪双倍命中(GDH)缓存替换方案.该方案综合考虑了内容的请求次数、传输代价、缓存代价,设计全新的多目标价值函数,用于评估内容的缓存价值,当缓存空间不足时,替换掉价值最小的内容,实现节点缓存内容价值的最大化.仿真结果表明,该替换算法提高了节点的命中率,降低了获取内容的平均跳数.     

内容中心网络中基于内容迁移的协作缓存机制

内容中心网络(CCN)是为了适应未来网络通信模式的转变,提供对可扩展和高效内容获取的原生支持而提出一种新型的网络体系架构,内容缓存机制是其研究的关键问题之一。现有机制在缓存节点的选择时往往过于集中,缓存负载分布严重不均,大大降低了网络资源利用率以及系统的缓存性能。该文提出一种基于缓存迁移的协作缓存机制,首先在缓存节点选择时考虑节点的中心性保证内容尽可能缓存在位置更重要的节点。同时,在缓存压力过大时,通过可用缓存空间大小、缓存替换率以及网络连接的稳定性等信息选择合适的邻居节点进行缓存内容的转移,充分利用邻居资源实现负载分担。仿真结果表明该机制能有效地改善缓存负载在节点上分布的均衡性,提高缓存命中率和缓存资源利用率并降低平均接入代价。     

P2P缓存系统中总开销最小的协作缓存策略

为降低P2P缓存系统中的全局开销,提出一种基于总开销最小的协作缓存策略。该策略综合考虑P2P缓存系统中的传输开销和存储开销,使用跨ISP域间链路开销、流行度、文件大小、存储开销来衡量文件的缓存增益。需要替换时,首先替换掉缓存增益最小的内容。实验结果表明,所提策略能够有效降低系统的总开销。     

内容中心网络中能耗优化的隐式协作缓存机制

综合考虑内容中心网络(CCN)的能耗优化及性能提升,该文提出一种内容中心网络中能耗优化的隐式协作缓存机制。缓存决策时,利用缓存节能量作为判决条件优先在用户远端节点缓存,并利用数据包携带最近上游缓存跳数信息进行隐式协作,减轻用户近端节点缓存空间的竞争压力,提高邻近节点缓存的差异性。缓存替换时,选取缓存节能量最小的缓存内容加以替换,达到最优的能耗优化效果。仿真结果表明,该缓存机制在性能上获得较优的缓存命中率及平均路由跳数,同时有效降低了网络能耗。     

变码率视频服务器间隔缓存的接纳策略和替换算法

本文提出了ROC(Resist-Overload Capability)缓存接纳策略和替换算法,解决了使用间隔缓存变码率视频服务器的缓存管理问题.确定性缓存接纳策略能提供确定的服务质量,却存在不适应交互应用和缓存利用率低的缺点;统计复用缓存接纳策略需要海量卷积运算,因此缺乏实用性;ROC缓存接纳策略通过简单运算,提供概率的缓存服务质量保证和较高的缓存利用率.仿真结果表明,在典型系统配置下,ROC缓存接纳策略和替换算法可以提高约25%的系统吞吐量;相对确定性缓存接纳策略和STP-L缓存替换算法,可以多服务约17%的视频流,平均缓存利用率也要高出约38%.     

基于内容价值的缓存替换策略

缓存替换机制是内容中心网络的重要研究问题之一,考虑到缓存空间的有限性,合理地对缓存内容进行置换,成为影响网络整体性能的关键因素。因此,设计了一种基于内容价值的缓存替换方案。该方案综合考虑了内容的动态流行度、缓存代价以及最近被请求的时间,构建了更实际的内容价值函数,并依据该内容价值函数,设计了有效的内容存储与置换方案。具体地,当缓存空间不足时,对已有缓存内容按照价值从小到大进行置换。仿真结果表明,相比于传统替换算法 LRU、LFU 和 FIFO,本文提出的方案有效地提升了网络节点的内容缓存命中率,降低了用户获取内容的平均跳数。     

基于P2P的CDN新型网络及缓存替换算法

对内容分发网络和P2P网络的特点进行了分析,给出了一种基于P2P的CDN新型网络自治缓存系统的体系结构,提出了自治缓存区域中智能缓存替换问题并给出了智能缓存替换方法和双关键字缓存替换算法.通过仿真实验,可以找到以运算复杂度低命中率高的关键字来实现缓存替换.     

基于内容流行度和节点中心度匹配的信息中心网络缓存策略

在信息中心网络(Information-Centric Network, ICN)中,利用网络内置缓存提高内容获取及传输效率是该网络构架最重要的特性。然而,网络内置的缓存存在应对大量的需要转发的内容时能力相对弱小,对内容放置缺乏均衡分布的问题。该文提出基于内容流行度和节点中心度匹配的缓存策略(Popularity and Centrality Based Caching Scheme, PCBCS),通过对经过的内容进行选择性缓存来提高内容分发沿路节点的缓存空间使用效率,减少缓存冗余。仿真结果表明,该文提出的算法和全局沿路缓存决策方案,LCD(Leave Copy Down)以及参数为0.7及0.3的Prob(copy with Probability)相比较,在服务器命中率上平均减少30%,在命中缓存内容所需的跳数上平均减少20%,最重要的是,和全局沿路缓存决策方案相比总体缓存替换数量平均减少了40%。     

ON-CRP：机会网络缓存替换策略研究

提出了一种新的机会网络缓存替换策略(ON-CRP,opportunistic networking cache replacement policy).与现有策略不同,该策略基于节点与数据项的相关度来选择要替换的缓存数据,并利用人类移动模式提取了目标地址匹配概率这一关键因素来对相关度进行判定;同时结合数据项的访问与更新频率比值这一重要因素来对缓存数据替换标准进行设计.仿真实验结果表明ON-CRP能够有效降低数据的远程访问延迟,与其他缓存替换算法相比网络开销降低了约30%,而数据的缓存命中率性能有约10%～30%的提高.     

基于节点社团重要度的ICN缓存策略

全网内置缓存是ICN(信息中心网络)架构中最重要的特性之一。为使被缓存的内容对象在空间和时间上分布更合理,提出了一种基于节点社团重要度的缓存策略（CSNIC）。该策略以社团为单位,不仅把内容缓存到社团内用户容易获取的节点处,而且使不同流行度的内容对象在各社团内节点处的时间分布上更合理。在多种实验条件下对CSNIC策略进行了仿真验证,结果表明该策略与CEE-LRU、Betw-LFU、Opportunistic相比,能更好地提升包括缓存命中率、跳数减少率、内容差异性及替换数量等在内的网络缓存性能指标,而且,CSNIC策略的额外开销较小。     

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.