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51.
一种高可用对象存储系统的数据组织研究 总被引:1,自引:0,他引:1
通过对现有不同存储系统的容错能力进行认真分析,提出了一种新的高可用对象存储系统架构HAOSS(High Availability Object Storage System).HAOSS系统分两层:上层存储的对象采用在多个设备之间的数据备份的方式来实现高可靠性,多个备份能够同时对外提供服务,保证系统的高性能,但是磁盘利用率比较低.下层采用RAID5,RAID6以及RAID_Blaurn等不同的容错编码来实现多盘容错功能,磁盘利用率较高,但是由于编码越来越复杂,容错编码需要大量的计算,性能受到很大的影响.在数据组织上,新对象和热点对象放上层,这样大部分请求都能够在上层命中,从而保证系统的性能.下层主要用来放不常用的数据.磁盘利用率比较高.在1000Mbps以太网环境下对HAOSS性能进行了测试,结果表明,HAOSS顺序读写性能都比较好,最大可以达到104MB/s,达到1000Mb以太网的理论最大物理带宽. 相似文献
52.
为了使系统满足品质要求并对不确定因素具有较强的鲁棒性,采用滑模控制方法。建立被控对象T-S模糊模型。针对系统状态不完全可测特点,采用迭代线性矩阵不等式方法,利用输出信息构造滑模面。根据系统品质要求,采用参数鲁棒设计方法,配置所需极点,确定相应在参数空间的映射关系。应用平行分布补偿算法,根据映射产生的参数样本训练T-S模糊控制器,实现等效控制律。在此基础上应用高增益方法设计切换控制律,保证系统对满足匹配条件的不确定因素具有较理想的自适应性。最后,直升机模型的仿真结果表明,方法具有很好的控制效果。 相似文献
53.
本文介绍HARSVERT—A系列高压变频器在重钢宽厚板工程步进梁式加热炉风机功率控制中的应用,主要论述了所采用的高压变频器的原理及控制系统技术方案。 相似文献
54.
55.
K.O. RochaAuthor VitaeS.M. ZanettiAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(2):654-661
Nanocrystalline WO3/TiO2-based powders have been prepared by the high energy activation method with WO3 concentration ranging from 1 to 10 mol%. The samples were thermal treated in a microwave oven at 600 °C for 20 min and their structural and micro-structural characteristics were evaluated by X-ray diffraction, Raman spectroscopy, EXAFS measurements at the Ti K-edge, and transmission electron microscopy. Nitrogen adsorption isotherms and H2 Temperature Programmed Reduction were also carried out for physical characterization. The crystallite and particle mean sizes ranged from 30 to 40 nm and from 100 to 190 nm, respectively. Good sensor response was obtained for samples with at least 5 mol% WO3 activated for at least 80 min. Ceramics heat-treated in microwave oven for 20 min have shown similar sensor response as those prepared in conventional oven for 120 min, which is highly cost effective. These results indicate that WO3/TiO2 ceramics can be used as a humidity sensor element. 相似文献
56.
There are several numerical methods for calculation of electric fields but they need some sort of experience and trial and error to get the correct solution. A genetic algorithm (GA) based approach is used to eliminate the need for the experience and to save time and effort spent in the trial and error. Two enhancement techniques, namely, Refreshment Method and No-Twins Method, are used with the GA operators to improve the performance of the GA in assessment of high voltage fields. The performance of these two enhancement techniques has been studied for computing the electrostatic field in high voltage applications. 相似文献
57.
网络教学系统已经逐渐成为新世纪教育教学发展的一种趋势,各高校在今后的教育教学中会更深入、广泛地应用。本文以我院网络教学平台为例,对网络教学平台的应用及管理情况进行探讨。 相似文献
58.
Recently, High Performance Computing (HPC) platforms have been employed to realize many computationally demanding applications
in signal and image processing. These applications require real-time performance constraints to be met. These constraints
include latency as well as throughput. In order to meet these performance requirements, efficient parallel algorithms are
needed. These algorithms must be engineered to exploit the computational characteristics of such applications.
In this paper we present a methodology for mapping a class of adaptive signal processing applications onto HPC platforms
such that the throughput performance is optimized. We first define a new task model using the salient computational characteristics
of a class of adaptive signal processing applications. Based on this task model, we propose a new execution model. In the
earlier linear pipelined execution model, the task mapping choices were restricted. The new model permits flexible task mapping
choices, leading to improved throughput performance compared with the previous model. Using the new model, a three-step task
mapping methodology is developed. It consists of (1) a data remapping step, (2) a coarse resource allocation step, and (3)
a fine performance tuning step. The methodology is demonstrated by designing parallel algorithms for modern radar and sonar
signal processing applications. These are implemented on IBM SP2 and Cray T3E, state-of-the-art HPC platforms, to show the
effectiveness of our approach. Experimental results show significant performance improvement over those obtained by previous
approaches. Our code is written using C and the Message Passing Interface (MPI). Thus, it is portable across various HPC platforms.
Received April 8, 1998; revised February 2, 1999. 相似文献
59.
M. K. Vijaya Sankar E. Eisner A. Garofalo D. Gates T. H. Ivers R. Kombargi M. E. Mauel D. Maurer D. Nadle G. A. Navratil Q. Xiao 《Journal of Fusion Energy》1993,12(3):303-310
HBT-EP is a new research tokamak designed and built to investigate passive and active feedback techniques to control MHD instabilities. In particular, HBT-EP will be able to test techniques to control fast MHD instabilities occurring at high Troyon-normalized beta, N Ba/Ip [Tm/MA], since it is equipped with a thick, close-fitting, and adjustable conducting shell. The major goals of the initial operation of HBT-EP have been the achievement of high beta operation (N 3) using only ohmic heating and the observation of MHD instabilities. By using a unique fast startup technique, we have successfully achieved these goals. A variety of MHD phenomena were observed during the high beta operation of HBT-EP. At modest beta (N 2), discharges have been maintained for more than 10 msec, and these discharges exhibit saturated resistive instabilities. When N approaches 3, major disruptions occur preceded by oscillating, growing precursors. During start-up, one or more minor disruptions are usually observed. A 1-D transport code has been used to simulate the evolution of the current profile, and these early minor instabilities are predicted to be double tearing modes. The simulation also reproduces the observed high beta operation when saturated neo-Alcator energy confinement scaling is assumed. 相似文献
60.
本文提出了一种既便于自动求值,又不致产生歧义的色谱分离优化目标函数。对于反相高效液相色谱RP-HPLC流动相组成优化问题,提出了新的高效迭代方法,并建立了组成优化专家系统。该系统包括优化搜索区域确定、实验谱图辨识、保留特性关系的自适应回归和最优目标预测等功能。经实验验证,该系统具有较高的迭代搜索效率。 相似文献