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。     

云计算关键技术之弹性伸缩控制技术认知研究

云计算的弹性伸缩控制技术因其以弹性可伸缩方式提供资源,提高了资源利用率和用户满意度,较好地解决了资源利用率和应用系统之间的矛盾,而成为云计算的关键技术.弹性伸缩控制技术,是指对一个系统适应负载变化进行调控的能力.弹性伸缩有纵横之分,弹性伸缩的需求是刚性、动态的.虚拟化技术的应用,使得弹性伸缩控制技术的优势发挥得更加充分.在弹性伸缩控制技术支持下,整合了动态负载均衡及资源配置机制的云计算中心,可以很好地解决大规模系统的有效管理问题,具有良好的应用前景.     

基于云计算资源的弹性伸缩创新及应用

随着信息技术和互联网的飞速发展,海量数据处理的需求日益增大,云计算作为一种资源共享模型应运而生.云计算的弹性伸缩控制技术因其以弹性可伸缩方式提供资源,提高了资源利用率和用户满意度.弹性伸缩有垂直和水平两个方面,水平伸缩主要是增加或减少虚拟机的数目,垂直伸缩是更改虚拟机的配置大小.然而,水平伸缩是一种粗力度的弹性调整方式,而且在应用过程中需要暂停应用,停顿时间比较大,会造成了资源的开销及成本浪费,而垂直伸缩虽然可以不中断服务即可对虚拟机大小进行重新配置,但是伸缩规模有限.针对水平伸缩和垂直伸缩各自的缺点,本文提出将水平伸缩和垂直伸缩两种方式相结合,既保证可以对大规模的伸缩需求做出及时响应,还可以满足短时间内对小规模需求进行资源调整,充分地利用了弹性伸缩的两个方面的优点,从而更大程度上地提高了资源利用率,降低了云计算资源的使用成本,进一步增大了用户的满意度.     

基于混合模型的云平台资源弹性伸缩方法

为使云资源数据最大化匹配平台主机的存储条件,保障云服务的质量水平,提出基于混合模型的云平台资源弹性伸缩方法。根据聚类混合系数指标,建立完整的初始定位条件,通过计算云数据优选残差加权量的方式,完成基于混合模型的云数据定位。在此基础上,预测平台主机的需求变化趋势,按照资源数据的采集与融合标准,定义必要的弹性扩容与伸缩扩容条件,实现基于混合模型云平台资源弹性伸缩方法的顺利应用。实验结果表明,与高斯负载型数据伸缩方法相比,在混合模型支持下,云平台主机可将资源数据最小压缩至0.125 bit,最大拉伸至16 bit,能够根据平台主机的实际存储条件,对云资源数据传输体积进行及时调整。     

基于mean-variance的服务集群负载均衡方法

大量并发请求任务进行分配时,负载调度机制是通过最小化响应时间及最大化节点利用率实现网络中节点的负载均衡,在基于遗传算法的负载均衡算法中,适应度函数设计对服务集群负载均衡效率产生重要的影响.对此提出了一种基于mean-variance的服务集群负载均衡方法对适应度函数进行优化,采用投资组合选择模型mean-variance进行最小化响应时间,以得到每个服务器资源利用率的权重,从而获得最优的分配组合,进而提高适应度函数的准确性和有效性.在不同服务环境下与其他模型进行比较,仿真结果表明,本文的负载均衡算法在节点利用率和响应时间方面使服务集群得到了更好的均衡.     

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.     

云计算环境下虚拟机资源均衡调度方法研究

虚拟机资源是云计算环境下的一类主要云服务资源,有效的资源调度方法对于改善负载均衡和提高资源利用率具有重要意义.针对虚拟机资源的调度问题进行分析,利用任务到达触发任务分配,当任务到达时,首先判断云服务资源池的运行状态,分为饱和与不饱和两种;然后针对当前任务请求下的云服务资源池状态,分别给出资源调度策略,并通过算例分析验证所提方法的有效性.所提虚拟机资源调度方法将有助于云服务资源池中虚拟机资源的均衡利用.     

云数据中心高能效的虚拟机迁移整合算法研究

基于多资源能效模型,通过改进CPU双阈值法提出了多资源双阈值法触发虚拟机迁移,并将基于粒子群算法的虚拟机放置算法应用于虚拟机的能效整合.仿真实验结果表明,与传统的启发式算法相比,该算法有效地减少了物理节点的启用数量和虚拟机迁移次数,使系统资源利用率更加均衡.     

基于云计算的资源负载预测

互联网的高速发展,数据量的急剧膨胀,云计算技术应运而生.为了实现按需动态的调整资源、提高利用率、节省成本,云计算的资源弹性可伸缩控制技术变得极其重要.但是弹性伸缩仍然存在一些不足,资源的弹性伸缩需要一定时间,动态变化的资源使用需求不能及时响应.为此,本文提出基于云计算资源的负载预测方法.该方法主要是利用线性回归模型对历史负载数据进行建模分析.历史负载值主要是针对CPU使用率、内存使用率、硬盘大小进行分析.在进行负载预测的过程中,首先建立线性方程,然后利用偏导数进行分析,克莱默法则进行求解,求出两个未知的回归参数.然后利用求得的线性方程预测下一时刻的负载值.实验表明该线性回归预测方法可以及时满足负载变化的需求、提高资源利用率、降低云计算资源的使用成本.     

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.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks