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A critical performance issue for a number of scientific and engineering applications is the efficient transfer of data to secondary storage. Languages such as High Performance Fortran (HPF) have been introduced to allow programming distributed-memory systems at a relatively high level of abstraction. However, the present version of HPF does not provide appropriate constructs for controlling the parallel I/O capabilities of these systems. In this paper, constructs to specify parallel I/O operations on multidimensional arrays in the context of HPF are proposed. The paper also presents implementation concepts that are based on the HPF compiler VFC and the parallel I/O run-time system Panda. Experimental performance results are discussed in the context of financial management and traffic simulation applications. 相似文献
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《Journal of the European Ceramic Society》2014,34(2):217-227
Tough ceramics can be made by introducing weak interfaces which deflect a growing crack. A simple discrete element model was employed to study crack growth in SiC-C laminate with graphite as weak interfaces. By modelling the three-point-bending test of the notched laminate, de-bonding, de-lamination and crack deflection were observed dynamically. The fracture features of the laminate as like “graceful failure” and R-curve behaviour were replicated both qualitatively and quantitatively. It has been revealed that the strength of the weak interface should be in a certain range to assure the appearance of the toughening effect. A minimum presence of the weak interface is required to increase the strength of the laminate. The employed model is explicit and simple, it can be used to reproduce the dynamic process of crack propagation in ceramic laminates and guide the design of the laminate's structure in the future. 相似文献
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We show the results of an experimental campaign to study the pressure drop during the restart of a core-annular flow from a stratified configuration. In normal core annular flow operations, due to fouling or pump failures, a core flow may not be sustained anymore and hence it stratifies. Since the pressure drops connected to the stratified flow regime are much larger than the ones of core annular, the flow suddenly stops. To restart it there are two possibilities: one is to try to provide a higher pressure gradient trying to restore the flow of water and oil, the other is to clean the pipe using water only: in both cases an attachment of a thin layer of oil on the pipe internal wall occurs and the pressure drop for water only or oil–water are higher than the previous ones with clean pipe wall. We focused our attention on the cleaning by water only and we provide experimental data on the evolution of the pressure drop as function of time in order to find when the pipe could be considered as perfectly cleaned or, at least, when the pressure drop are low enough to restart the oil flow. The experimental results are finally compared with a two-fluid model available in literature. 相似文献
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智能计量仪表中掉电重启动的实现方法 总被引:1,自引:0,他引:1
The method of imple menting restart after
power outagein in struments based on single chip computer is introduced. The requirement
of restart and the detection of power outage as well as the flow charts of power outage
processing procedure and restart program are described. 相似文献
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本文介绍了变频器的控制模式。主要有:V/F控制、开环矢量控制、带PG反馈的矢量控制,等。此外,本文还介绍了变频器各控制端子的功能,如输入控制端子、输出控制端子、报警控制端子等。最后,介绍了变频器的几种保护功能。 相似文献
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融合社交信息的推荐算法有效缓解了推荐算法中的数据稀疏性问题和冷启动问题,近年来受到极大的关注。但社交信息依然存在数据稀疏性问题,而且社交网络提供的二值数据无法衡量不同用户间的信任程度。针对这些问题,利用重启随机游走算法获取社交网络中的重要节点。提出重要节点信任传播算法建立重要节点和其他用户节点之间的信任关系,同时利用节点的结构信息进一步量化用户间的信任权重,以得到更精确的推荐结果。在三个公开数据集上的实验表明,结合重要节点信任传播的社会化推荐算法(INTP-Rec)丰富了社交信息,有效地提高了推荐算法的准确率和召回率。 相似文献
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本文介绍罗克韦尔(A—B)ControlLogix PAC在天然气配气站控制系统中的应用。作者概述了该配气站的工艺流程;简介了以冗余的ControlLogix PAC为核心的该控制系统的拓扑架构、软硬件配置和主要功能。该文还着重对ControlLogix冗余系统的特点以及PID调节的无扰动重启和天然气流量计量两个关键环节进行了较为详细的阐述。 相似文献
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New acceleration schemes and restarting procedures are defined and studied in view of application to the EM algorithm. In most cases the introduced algorithms circumvent the problems of stagnation and degeneracy. Their behavior is analyzed on real data sets. 相似文献