一种基于动态资源采集的Hadoop作业调度算法

为了克服Hadoop中基于槽的资源模型对集群资源的浪费,提高Hadoop集群的资源利用率,提出了一种基于动态资源采集的Hadoop作业调度算法.通过在作业运行过程中动态采集部分任务的CPU,内存和IO的资源利用率来评估同一作业中其他任务的资源需求,然后根据任务的实际资源需求以及TaskTracker节点的负载情况进行任务调度,以充分利用各TaskTracker节点的计算资源.通过对比实验表明该调度算法能明显提高集群的资源利用率,缩短作业的完成时间.     

基于Hadoop的分布式哈希算法实现

互联网的发展使得计算密集型的任务正在逐渐走向分布式和云计算。文中对Hadoop项目中的MapReduce和HDFS进行了研究,采用HDFS作为底层分布式文件系统,MapReduce作为编程框架来实现哈希算法。通过对多个节点中的测试结果的分析表明,在Hadoop上运行哈希函数的任务,能够起到在多台计算机的群集中分摊负载的效果,并且有效地减少了任务的总时间开销。以Hadoop为基础的云计算平台具有良好的可靠性和可扩展性,对于哈希算法在Hadoop平台上的实现和测试,为将来密钥恢复等系统的研究和搭建提供了良好的基础。     

Mapreduce模型及支撑系统概述

MapReduce是由并行编程模型及相关支撑系统组成的数据处理框架,通过定义接口和运行时支持库,通过定义良好的接口和运行时支持库,能够自动并行执行大规模计算任务,通过隐藏底层实现细节,降低实现并行编程的难度,Hadoop是目前MapReduce框架最流行的开源实现.文章首先介绍了MapReduce并行编程模型及其hadoop的运行原理、运行机制,深入研究了MapReduce计算任务在Hadoop系统中的运行过程.     

异构Hadoop集群下自适应平衡数据存储的大数据放置策略

Hadoop是一种处理和存储大数据的平台,针对异构Hadoop集群下采用均等数据分配方法易降低系统计算性能的问题,提出一种自适应平衡数据存储的大数据放置策略。根据异构集群中各节点的计算能力比例,将数据分配到节点中。在任务处理过程中,根据反馈的任务完成时间信息,动态更新节点的能力比例,自适应调整数据分配,从而使异构Hadoop集群中各节点处理数据的时间大致相同,降低节点之间的数据移动量,提高了节点利用率。实验结果表明,该策略能够有效缩减任务完成时间,提高了系统的整体性能。     

一种Hadoop异构集群下提高数据本地性的分发算法

Hadoop异构集群由于不同slave节点的硬件配置不同(例如CPU、内存、磁盘等),每个节点的Map任务和Reduce任务的slot也不同。文章通过研究当前Hadoop系统上实现数据本地性的算法,提出一种基于异构节点的性能来分发Map任务的输入数据的算法,该算法评估每个slave节点的Map任务执行速度,将输入数据放在运行更快的节点上,以达到更好的数据本地性。     

基于Hadoop平台的图像识别

基于Hadoop平台以字符识别为例建立图像识别系统。所设计的系统在借鉴云平台高扩展性以及高效性等优势的基础上,有效地解决了传统字符识别系统在计算效率以及数据处理方面所存在的不足。通过实例验证了基于Hadoop平台进行图像识别相比单机图像识别系统具有更高的效率:在仅具有2个节点的Hadoop图像识别平台上进行字符图像的识别时,由于节点数较少,在2台计算机中消耗的数据交换时间使得Hadoop图像识别平台进行图像识别的总时间甚至超过了单台计算机所使用的时间,而在具有4个节点、6个节点和8个节点的Hadoop图像识别平台上,处理相同图像所使用的时间随着节点数量增多而降低。     

树形网格自适应调度模型研究

提出一种基于树形计算网格的自适应调度模型,实现对小粒度独立任务和用户大作业的自适应最优调度.通过对网格环境的实时检测,给出了基于节点负载状况、节点任务执行时间和任务特性的自适应调度算法.实验证明该任务调度模型在负载平衡和容错方面具有良好的性能.     

边缘计算中云边任务下发策略研究

目前边缘计算的相关研究大部分着眼于如何将设备端数据卸载至边缘端进行处理,而未考虑云中心如何高效率、低延时地将不同任务下发至边缘节点的问题.针对该问题,文中提出了一种边缘计算架构模型,通过对任务进行统一建模,使用改进的Dijkstra算法得到任务下发最优路径,减少所需计算节点数量和提升计算性能,使其能在最短的时间内下发到...     

一种基于云计算架构的业务流程优化研究

本文提出了一种将业务流程进行优化分解成为可以进行独立并行处理任务的方法,可以在云计算环境下分组处理具有共同特征的计算和操作任务,实现优化资源调配.通过 Hadoop MapReduce 并行计算架构进行模拟验证,实验结果表明了该方法在业务处理效率、资源使用和灵活性方面的优势,在大量在线和批量业务流程处理领域具有一定的应用和深入研究价值.     

云计算下MapReduce多组容错机制架构的分析与研究

提出了MapReduce多组容错机制,在传统的Hadoop MapReduce架构上进行改进,即在同机柜中的TaskTracker节点之间增加了多组关系,这样可以缩短发现失效节点的时间,同时减轻JobTracker节点的负荷,减低了带宽使用率,减少网络拥塞.通过实验证明,MapReduce多组容错机制提高了MapReduce的工作效率.     

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.