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Zhou Dong Lv Chuan Li Yongxiang Guo Zhiqi 《Quality and Reliability Engineering International》2014,30(2):247-256
The aim of the maintenance allocation is to allocate the maintenance time to the subsystems reasonably and accurately. Traditional mean time to repair (MTTR) allocation methods are widely used in the industry. However, there are many deficiencies in practical application, which is inconsistent with the purpose of the maintenance allocation. To allocate the MTTR more precisely and reasonably, a better model is needed. The aim of this paper is to develop a maintenance allocation model, which can improve the applicability and operability, and solve the residue problem that exists in maintenance allocation. A case study is used to demonstrate how the model can be applied in practice. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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We present an upper bound for the product of the k largest roots of a monic polynomial of degree n with complex coefficients. For that, we use the theory of compound matrices and the localization of the eigenvalues of matrices.
Received: February 26, 1996; revised version: March 20, 1997 相似文献
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分数阶反常扩散方程具有深刻的物理背景和丰富的理论内涵,其数值解法的研究具有重要的科学意义和工程应用价值.针对二维时间分数阶反常扩散方程,本文研究一种交替分带 Crank-Nicolson 差分的并行计算方法(ABdC-N 方法).该格式是在交替分带技术的基础上,结合经典显式、隐式和 Crank-Nicolson 差分格式构造而成.理论分析和数值试验表明,ABdC-N 方法是无条件稳定和收敛的,具有良好的计算精度和并行计算性质,并且计算效率远优于经典的串行差分方法,证实本文 ABdC-N 差分方法求解二维时间分数阶反常扩散方程是有效的. 相似文献
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通过DEST软件模拟出医院住院部全年动态负荷情况,分析了医院建筑负荷的特点.建立土壤源热泵系统地埋管换热物理和数学模型,以FLUENT为分析工具,对该建筑的地源热泵系统进行以运行时间为变量的数值计算分析,得到不同运行时间下的地温和管内流体的温度分布规律.以间歇运行时间为变量,得到辅助冷却模式下地温和管内流体的温度分布规律,提出了医院建筑地埋管地源热泵系统的优化运行模式. 相似文献
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楔形上Altman不等式的推广 总被引:2,自引:0,他引:2
本文给出Bnnach空间中楔形上半紧1-集压缩映象A的方程Az=ux解的某些结果。其次,还扩充和改进几个具Altman型行列式的不等式的不动点定理。 相似文献
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失稳现象在齿轮耦合的转子-轴承系统中时有发生,失稳原因一直是人们所关心的问题。通过数值计算发现,化轴之间描率分配以及传动比对系统的稳定性有很大的影响;在研究的系统中存在着影响系统稳定运行的薄弱环节,当传动比和轴瓦形式发生变化时,该薄弱环节将从一个子系统转移到另一个子系统;合理地选择轴瓦形式有利于系统稳定性的提高;系统失稳时将产生“倍速涡动”。 相似文献
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应用时间序列移动平均模型预测加工精度的研究 总被引:1,自引:0,他引:1
探讨应用时间序列移动平均模型描述外圆磨削过程 ,介绍了时间序列移动平均模型的特点。针对柱塞外径加工精度的实测数据集 ,在计算机上进行了仿真建模。应用实例表明 ,时间序列移动平均模型适于描述线性趋势分布的外圆磨削过程。 相似文献
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To estimate the mean in a two-stage nested model one would usually use a weighted average of the group sample means with the weights summing to one. Among all those with nonrandom weights we find the estimator that maximizes the minimum possible efficiency. It is found to perform very well in comparison with other estimators that have been proposed. 相似文献
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提出一个飞控系统半物理仿真方案。仿真系统基于嵌入式实时操作系统VxWorks,使用RTW工具箱将飞机的Simulink仿真模型下载到PCI04计算机平台,提高了半物理仿真的效率和可靠性。设计开发支持PC104嵌入式计算机的VxWorks板载支持包,研究RTW的代码生成过程,解决了实现该方案的关键技术。 相似文献
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A relatively simple relationship is presented for determining the mean time to failure for systems with redundancy of the type where r out of n units must be operating for the system to be operating. The special case is for units that have constant failure rates. 相似文献
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管理体系文件庞大,涉及到实验室工作的方方面面,要自觉运行管理体系,还是有一定难度的。为较好地运行管理体系,本文将依据本实验室的管理体系文件,对管理体系文件进行梳理,并着重对程序文件的结构、特点、运行时机等方面进行详细分析,从而为大家理清管理体系文件的脉络,促进管理体系运行工作的顺利开展。 相似文献
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《Drug development and industrial pharmacy》2013,39(5):649-655
AbstractAnhydrous citric acid and sodium bicarbonate were granulated with ethanol in an extruder. A rough estimate of the dwell time was obtained by adding a small amount of colour in the inlet port and measuring the time until it reached the outlet. The mean residence time was calculated from results obtained when analyzing the colour content of the continuously sampled granulations after drying. There was a significant relationship between dwell time and mean residence time. After elimination of the abnormal values of three of the factor combinations, the degree of significance for the slope of the line increased from P=0.003(**) to P=0.0001(***). The mean residence time was significantly influenced by the process variables screw speed and powder flow rate. Higher levels of these two factors reduced the mean residence time. 相似文献
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提出了生产系统时间熵的概念,对精益管理的导入如何改善生产系统中“人、机、料、法、环”五大要素继而影响生产系统时间熵进行了分析,并以科学性和实用性为原则,结合定性与定量的分析方法,构建了生产系统精益管理导入效果评价指标体系和基于时间熵的评价模型,为定量评价生产系统精益管理导入效果提供有效依据。利用所构建的指标体系和评价模型对一家胶管企业生产系统精益管理导入效果进行了量化评价,结合该企业精益管理导入实际情况,验证了所建指标体系和模型具有较好的适用性和有效性,为生产系统的精益管理导入效果评价提供了新的思路和方法. 相似文献
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Scientific analysis of servicing processes has resulted in the development of sequential servicing where a unit requiring service is processed through a fixed number of stages sequentially. A detailed study of such a system has been presented by Boling (1). This paper considers a large servicing system consisting of a finite number of identical sequential service lines. These lines are operated in parallel, but interline transfers of units are made whenever advantageous. Using time homogeneous Markov chains, a model is developed for analyzing the operation of such a system, which shows that interline transfers of units result in improved performance of the system. Practical considerations in the implementation of this mode of operation are discussed, and the model is illustrated. 相似文献