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161.
郭艳丽 《中国人民武装警察部队学院学报》2006,22(6):18-21
分析了液态烃泵在设计制造、密封失效、静电危害、安全管理等方面存在的火灾危险性,并从密封技术的改进、泵结构的改造、生产操作安全规程的制定和实施等方面探讨其预防对策,为石油化工行业液态烃泵的安全使用和消防技术管理工作提供参考依据。 相似文献
162.
从线性化的Euler方程和连续方程出发,采用线性自由面条件,通过傅里叶变换法研究水平运动点源在分层流体中产生的内波.利用源汇分布法分析运动潜体产生的lee波,采用稳定相法计算远场速度.计算结果表明,高模态内波的波域角小于低模态内波的波域角,内波的波域角小于Kelvin波的波域角;随航速增大lee波主要表现为散波. 相似文献
163.
The deterministic problem for finding an aircraft's optimal risk trajectory in a threat environment has been formulated. The threat is associated with the risk of aircraft detection by radars or similar sensors. The model considers an aircraft's trajectory in three‐dimensional (3‐D) space and represents the aircraft by a symmetrical ellipsoid with the axis of symmetry directing the trajectory. Analytical and discrete optimization approaches for routing an aircraft with variable radar cross‐section (RCS) subject to a constraint on the trajectory length have been developed. Through techniques of Calculus of Variations, the analytical approach reduces the original risk optimization problem to a vectorial nonlinear differential equation. In the case of a single detecting installation, a solution to this equation is expressed by a quadrature. A network optimization approach reduces the original problem to the Constrained Shortest Path Problem (CSPP) for a 3‐D network. The CSPP has been solved for various ellipsoid shapes and different length constraints in cases with several radars. The impact of ellipsoid shape on the geometry of an optimal trajectory as well as the impact of variable RCS on the performance of a network optimization algorithm have been analyzed and illustrated by several numerical examples. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006 相似文献
164.
Variation reduction of manufacturing processes is an essential objective of process quality improvement. It is highly desirable to develop a methodology of variation source identification that helps quickly identify the variation sources, hence leading to quality improvement and cost reduction in manufacturing systems. This paper presents a variation source identification method based on the analysis of the covariance matrix of process quality measurements. The identification procedure utilizes the fact that the eigenspace of the quality measurement covariance matrix can be decomposed into a subspace due to variation sources and a subspace purely due to system noise. The former subspaces for different samples will be the same if the same variation sources dominate. A testing procedure is presented, which can determine the closeness of the subspaces under sampling uncertainty. A case study is conducted to illustrate the effectiveness of this methodology. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006. 相似文献
165.
把AHP(Analytic H ierarchy Process)方法运用于装备研制项目风险分析,实现了风险因素的排序、系统总风险的评价以及风险响应措施的选择。在风险发生概率和风险损失的基础上,将风险因素的可控制性和用户满意度风险也同时作为风险判断准则,使得风险的评价更合理、更准确地反映项目实际。最后给出了风险因素排序及风险响应措施选择的应用实例。 相似文献
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图形图像技术在仿真中的应用除使之高度可视化外,更重要的是引入了“三维描述”的概念,扩大了“定量” 相似文献
169.
A mathematical model of portfolio optimization is usually represented as a bicriteria optimization problem where a reasonable tradeoff between expected rate of return and risk is sought. In a classical Markowitz model, the risk is measured by a variance, thus resulting in a quadratic programming model. As an alternative, the MAD model was developed by Konno and Yamazaki, where risk is measured by (mean) absolute deviation instead of a variance. The MAD model is computationally attractive, since it is easily transformed into a linear programming problem. An extension to the MAD model proposed in this paper allows us to measure risk using downside deviations, with the ability to penalize larger downside deviations. Hence, it provides for better modeling of risk averse preferences. The resulting m‐MAD model generates efficient solutions with respect to second degree stochastic dominance, while at the same time preserving the simplicity and linearity of the original MAD model. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 185–200, 2001 相似文献
170.
无信息先验下几种不同Bayes估计的比较 总被引:5,自引:0,他引:5
讨论了在二项分布场合关于成功率的不同无信息先验分布下的Bayes估计 ,并从Bayse风险的角度对它们进行了比较 相似文献