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481.
For a component or a system subject to stochastic degradation with sporadic jumps that occur at random times and have random sizes, we propose to model the cumulative degradation with random jumps using a single stochastic process based on the characteristics of Lévy subordinators, the class of nondecreasing Lévy processes. Based on the inverse Fourier transform, we derive a new closed‐form reliability function and probability density function for lifetime, represented by Lévy measures. The reliability function derived using the traditional convolution approach for common stochastic models such as gamma degradation process with random jumps, is revealed to be a special case of our general model. Numerical experiments are used to demonstrate that our model performs well for different applications, when compared with the traditional convolution method. More importantly, it is a general and useful tool for life distribution analysis of stochastic degradation with random jumps in multidimensional cases. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 483–492, 2015 相似文献
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针对目前大学自习教室资源浪费普遍存在的现象,将学生上自习与否视为独立同分布随机变量,从自习教室的管理与维护成本、电费成本以及学生的满意度3个方面出发,建立了双目标随机规划模型,并在模型基础上提出了大学自习教室设置的一般方法。通过实例分析,对模型的正确性和有效性进行了论证。结果表明:在各种情况下,该模型都能很好地解决自习教室设置这一问题,并且能在学生满意度较高的条件下,节约能源13%以上。该模型可以有效地对自习教室进行优化设置,不仅提高了资源利用水平,而且节约了能源。 相似文献
484.
In this paper, we investigate systems subject to random shocks that are classified into critical and noncritical categories, and develop two novel critical shock models. Classical extreme shock models and run shock models are special cases of our developed models. The system fails when the total number of critical shocks reaches a predetermined threshold, or when the system stays in an environment that induces critical shocks for a preset threshold time, corresponding to failure mechanisms of the developed two critical shock models respectively. Markov renewal processes are employed to capture the magnitude and interarrival time dependency of environment-induced shocks. Explicit formulas for systems under the two critical shock models are derived, including the reliability function, the mean time to failure and so on. Furthermore, the two critical shock models are extended to the random threshold case and the integrated case where formulas of the reliability indexes of the systems are provided. Finally, a case study of a lithium-ion battery system is conducted to illustrate the proposed models and the obtained results. 相似文献
485.
为降低传统层次分析法(analytic hierarchy process,AHP)赋权过程主观片面性影响,提出了一种综合AHP与Arena仿真建模技术的无人机训练资源配置效率评价方法。基于飞行训练流程分析,确定了训练资源配置效率影响因素和效率评价指标,建立了层次型综合评价体系,概括了AHP-Arena综合评价步骤。利用Arena建模软件构建训练流程动态仿真系统并验证有效性,采用单变量数值仿真法、均方差决策法完成了影响因素客观赋权,通过线性加权综合法得出综合评价系数,实现资源配置效率评价与方案优选。实例应用说明了该方法的有效性,同时,该方法可推广至其他类似的训练过程中,亦可为其他多因素、多指标评价决策过程提供借鉴。 相似文献
486.
邹涛 《武警工程学院学报》2014,(6):11-14
为提高无线多跳网络的吞吐量和传输可靠性,提出一种信道分配算法。该算法优先考虑最小生成树上的可用信道,为每个节点分配信道资源;然后考虑利用生成树外其他可用链路,为节点提供信道资源,以提高吞吐量。算法通过考虑每个用户的通信需求,可以充分利用空闲信道资源。仿真结果显示,相比于不考虑最小生成树外链路时,有效地提高了网络整体吞吐量。 相似文献
487.
Hadas Shabtay 《Defence and Peace Economics》2014,25(5):461-480
This study presents a framework and models for the analysis of government budget allocation into defense and civilian expenditures in situations of uncertainty about the incidence of war. The models display the intricate relationships between security levels, subjective probabilities of the occurrence of war, and potential war damages. We show that poor countries tend to perceive greater probabilities of war than their richer rivals, and that the psychological burden of insecurity is larger when the country’s wealth is larger and when its preference for security is higher. We apply our models to the Israeli–Syrian arms race and show that the higher rate of growth of Israel’s gross domestic product relative to that of Syria is expected to lead to an increase in Syria’s perception of the likelihood of war and to a decrease in Israel’s perception of such a likelihood. We also show that if Syria’s regime becomes ideologically more extreme, the monetary cost of maintaining Israel’s security at the level that it enjoyed prior to the change will be very high, whereas the monetary cost of maintaining Israel’s welfare will be moderate. 相似文献
488.
任务分配是多导弹协同攻击目标的重要前提,在充分考虑满足复杂战场环境各种约束的条件下,提出了基于混沌粒子群算法的实时动态算法,使得算法在求解WTA问题时具有处理意外目标和任意时刻响应当前战场状态的实时动态特性。并为了解决战场环境中各不确定性因子对新加入目标优先级的影响,提出基于三元区间数表示关联熵的复合物元目标排序方法。 相似文献
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