云环境下基于迁移的虚拟机集群优化算法

针对云环境中虚拟机集群负载不均衡问题,提出一种基于虚拟机迁移的集群优化算法。通过对节点负载的实时监测,动态调整各种资源的权重,根据资源权重选择可最大程度降低主机负载的虚拟机进行迁移。该算法利用预测机制,消除主机资源利用率的临时越界引起的不必要的虚拟机迁移。在选择目标节点时,采用多目标决策法,兼顾多资源匹配率,服务级目标违背率(SLA)等多种管理目标。实验结果表明,与同类型的负载均衡算法相比,该算法能减少迁移次数,降低SLA违背率。     

基于虚拟机迁移的虚拟机集群负载均衡策略研究

针对虚拟机集群资源负载不均衡的问题,提出了一种多策略与预测机制相结合的、基于虚拟机迁移的负载均衡方案.对导致系统过载的不同类型的资源采用不同的均衡策略,能够更加有效地使系统恢复正常.采用预测机制,消除瞬时峰值导致的不必要的迁移,可以减少传统的基于单阈值策略中虚拟机的迁移频率.在触发迁移后采用概率转发方式选择目的节点,能够有效解决群聚冲突问题.实验结果表明,本方案能够有效地实现系统的负载均衡.     

云计算中基于能耗比例模型的虚拟机调度算法

针对资源虚拟化环境中的混合型负载调度问题,提出一种基于能耗比例模型的虚拟机调度算法.该算法利用处理器的"性能计数器"机制来评估各个虚拟机的近期能耗状态,并采用"最近最小能耗比例优先"的策略进行调度.理论分析给出了该算法的有效性证明和相关特性.实验结果显示,当系统面对混合型负载时,基于能耗比例模型的调度算法在"调度偏差"和"相对能效"两方面明显优于现有的虚拟机调度算法.     

云环境下基于租户的虚拟机分层放置策略

云环境下租户申请虚拟机来部署应用或者计算任务,这些虚拟机之间的通信较频繁,需要消耗较多的网络资源.为了减少网络资源的消耗和物理主机资源的浪费,提出了基于租户的初始化放置算法,并结合运行时放置算法调节虚拟机的位置.仿真结果表明,新算法在达到放置目标的同时,减少了需要重新放置的虚拟机数目,降低了迁移代价.     

基于KVM的虚拟机Post-Copy动态迁移算法稳定性优化

虚拟机动态迁移技术为虚拟化系统的资源调度提供了强有力的支撑,Post-Copy算法作为虚拟机动态迁移的两个核心算法之一,凭借其总体迁移时间稳定与迁移停机时间短的优点,一直是国内外学者研究的热点问题。对虚拟机的故障容错机制、迁移过程中的内存页面传输方式与缺页错误的关联性,以及QEMU-KVM平台源码进行了深入的研究,提出了基于事务同步的故障容错方法以提升Post-Copy迁移算法的稳定性。试验结果表明,提出的虚拟机Post-Copy迁移优化算法,能保证迁移过程中源端虚拟机故障、目标端虚拟机故障以及网络故障的迅速修复,能通过较小的代价解决稳定性问题,所提出的方法有效地提升了Post-Copy迁移算法的稳定性,也为以后的优化研究方向提供了参考。     

基于工作负载预测的虚拟机整合算法

针对云计算环境下满足负载均衡、自动伸缩、绿色节能等需求时所面临的虚拟机(VM)迁移问题,该文设计一种面向云计算基础设施基于工作负载预测的整合调度算法。通过有机结合基于工作负载预测的主动控制技术和基于实际系统状态信息的被动控制技术,并采用指数平滑预测模型预测未来时刻的工作负载情况,提出虚拟机选择阶段最大未来工作负载优先和虚拟机安置阶段比较资源需求队列的虚拟机整合算法。仿真表明,该算法利用基于预测的资源整合方式减少了服务器使用量、虚拟机迁移次数和服务等级协议违例次数,有效提升了以数据中心为核心的云基础设施整体资源利用率。     

云环境下基于虚拟机动态迁移的调度策略研究

针对目前云环境资源调度采用静态负载均衡策略易于导致资源浪费的问题,提出了一种双限定值的虚拟机动态迁移的调度策略.该策略将当前负载状况与负载过重或过轻时两个限定值比较,选择介于二者之间能耗较低的虚拟机迁移至目标节点.仿真实验表明,该策略能够减少迁移次数,降低虚拟机迁移能耗,从而尽可能达到负载均衡和满足服务等级协议的需求.     

基于合作博弈的多虚拟机实时迁移带宽分配机制

IaaS云计算平台采用虚拟机实时迁移技术进行资源动态调度和管理。在实际应用场景下,需要并行实时迁移多个虚拟机。由于实时迁移算法本身以最大利用带宽的方式进行数据传输,存在着迁移进程间竞争带宽的问题,无法保证带宽全局最优分配,影响整体迁移的性能。提出一种基于合作博弈的多虚拟机实时迁移带宽分配机制,将带宽分配问题建模为一个纳什议价,通过求解纳什议价解得到帕累托最优的带宽分配方案,并在实际的虚拟化平台上进行了实现。实验结果表明,相比标准的并行实时迁移,所提出的带宽分配机制能够公平有效地分配带宽,提高了并行实时迁移的性能。     

基于改进蚁群算法的虚拟机放置方法研究

针对云计算资源调度中虚拟机到物理机上的部署问题,提出了基于剩余资源控制阈值和匹配度函数的虚拟机放置模型,该模型采用三重因子的目标函数,为剩余资源总量、新开物理机数量及剩余资源标准差提供了约束;为求解该模型,提出了基于大请求先安置原则的改进蚁群算法,并对算法的及参数进行了改进。仿真实验表明和其它几种算法比较,改进蚁群算法有更好的收敛性和更强的寻优能力;此外,实验结果也表明该放置模型能有效提高资源利用率,降低能耗。     

基于强化学习的虚拟机资源自动配置

虚拟机技术允许多个虚拟机在同一台物理主机上共享资源.为了响应应用需求的变化或者是资源供应的变化,分配到虚拟机上的资源应该能够动态的重新配置.为此,本文提出了一个基于强化学习的算法来自动处理配置进程,即（Standard Reinforcement Learning Auto-Configuration）. 强调了基于算法的模型来解决在资源管理系统的稳定性和适应性问题.这里通过在一个云环境仿真软件CloudSim在基于虚拟机的云测试床实施具有代表性的服务器负载的实验,结果证明了的有效性.这个方法可以在小规模系统里发现最优（或接近最优）的配置策略,并且表现了很好的稳定性和适应性.     

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。     

A Versatile Mixed-Signal Pin Approach for Cost-Effective Test of Automotive ICs

Integrated circuits (ICs) intended for increasingly sophisticated automotive applications bring unique test demands. Advanced ICs for applications such as highly integrated automatic braking system (ABS) and airbag controllers combine high voltage digital channels, significant VI demands and precise timing capability. Along with continued missioncritical reliability concerns, the trend toward higher voltage operation and increased device integration requires specialized test capabilities able to extend across the wide operating ranges found in automotive applications. Among these capabilities, automotive test requirements increasingly dictate a need for a cost-effective versatile mixed-signal pin electronics with very high data rates reaching up to 50MHz with a voltage swing of-2 V to +28 V.     

Optical vibration and deviation measurement of rotating machine parts

It is of interest to get appropriate information about the dynamic behaviour of rotating machinery parts in service. This paper presents an approach of optical vibration and deviation measurement of such parts. Essential of this method is an image derotator combined with a high speed camera or a laser doppler vibrometer （LDV）.     

社长序言（英文）

正Happy New Year!As we step into a new year,we take a look back at the key feature topics covered in China Communications over the past 12 months and set out our expecta-     

Call for Papers

正Introduction Jointly sponsored by the China Institute of Communications(CIC)and the IEEE Communications Society(IEEE ComSoc)since the year 2013,China Communications,currently,is aiming to gradually realise the transition from journal to magazine content and style.     

INTEGRATION OF OPTICAL AND WIRELESS NETWORKS

正For a long time,optical and wireless systems/net-works are developed in separate communities witha few attempts for in-depth convergence.In fact,it prom-ises many advantages to combine the optical and wire-less technologies in the levels of systems and networks.Recently,both academia and industry have made manyefforts to enter a new phase of development to take op-tical and wireless systems as fully integrated networks.To provide high bandwidth and reliable service for bothfixed and mobile users,a well-designed network must     

Call for Papers—Feature Topic,Vol.12,No.3,2015

正Smart Grid Communications The electric power industry is undergoing profound changes as the industry aims to capture the promise of a smart grid for a sustainable energy future.Enabled by the advanced sensing devices such as Phasor Measurement Units(PMUs),increasingly powerful