火灾安全评价方法研究

火灾安全评价是利用系统工程的方法对拟建或已有工程、系统可能存在的危险性及可能产生的后果进行综合评价和预测,并根据可能导致的火灾事故风险的大小,提出相应的安全对策措施,以达到工程、系统安全的过程。主要论述了火灾安全评价的目的、火灾安全评价的意义、火灾安全评价的一般程序、火灾安全评价方法选择、火灾安全评价方法的比较及火灾安全评价方法在消防中应用。     

Performance evaluation of a production/inventory system with periodic review and endogenous lead times

This paper considers a discrete time, single item production/inventory system with random period demands. Inventory levels are reviewed periodically and managed using a base‐stock policy. Replenishment orders are placed with the production system which is capacitated in the sense that there is a single server that sequentially processes the items one at a time with stochastic unit processing times. In this setting the variability in demand determines the arrival pattern of production orders at the queue, influencing supply lead times. In addition, the inventory behavior is impacted by the correlation between demand and lead times: a large demand size corresponds to a long lead time, depleting the inventory longer. The contribution of this paper is threefold. First, we present an exact procedure based on matrix‐analytic techniques for computing the replenishment lead time distribution given an arbitrary discrete demand distribution. Second, we numerically characterize the distribution of inventory levels, and various other performance measures such as fill rate, base‐stock levels and optimal safety stocks, taking the correlation between demand and lead times into account. Third, we develop an algorithm to fit the first two moments of the demand and service time distribution to a discrete phase‐type distribution with a minimal number of phases. This provides a practical tool to analyze the effect of demand variability, as measured by its coefficient of variation, on system performance. We also show that our model is more appropriate than some existing models of capacitated systems in discrete time. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

Some probability functions in reliability and their applications

There has been much research on the general failure model recently. In the general failure model, when the unit fails at its age t, Type I failure (minor failure) occurs with probability 1 ? p(t) and Type II failure (catastrophic failure) occurs with probability p(t). In the previous research, some specific shapes (constant, non‐decreasing, or bathtub‐shape) on the probability function p(t) are assumed. In this article, general results on some probability functions are obtained and applied to study the shapes of p(t). The results are also applied to determining the optimal inspection and allocation policies in maintenance problems. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

基于DS/AHP的导弹发射阵地选择方法

战术导弹发射阵地选择是导弹作战兵力运筹的重要组成部分,其本质是一多准则多属性决策问题。传统的层次分析法无法明确描述这类问题中所蕴涵的不确定性,通过DS证据理论的引入,研究了战术导弹发射阵地选择的DS/AHP方法,应用实例说明了该方法的可行性和有效性。     

基于GQM的装备软件可靠性参数选取方法

针对装备软件无可靠性定量要求以及开发过程缺少监管的问题,提出基于GQM(Goal-Question-Metric)的装备软件可靠性参数选取方法。首先构建了软件可靠性通用参数集和装备软件可靠性特有参数集,然后按照GQM方法的框架,从不同角度出发,制定装备软件可靠性度量目标,列出为实现目标需要回答的一系列问题,进而以回答问题的方式,确定不同情况下适用的软件可靠性参数,最终建立装备软件可靠性参数体系。     

雷达天线扫描方式的自动识别方法

为了对雷达天线扫描方式进行自动识别,改进开发了天线扫描方式模拟器,并分别研究了电子扫描和机械扫描的特征提取和识别方法。基于最大主瓣脉冲序列的特征参数实现电子扫描和机械扫描的区分,然后基于单个天线扫描周期脉冲序列的特征参数实现8种机械扫描方式的自动识别。仿真结果表明,本文方法能够区分一维电扫、二维电扫和机械扫描,并且采用支持向量机决策树对机械扫描方式的识别正确率高于决策树方法。     

基于群决策协同网络信息的掩护机编队选择

针对任务机群中掩护机编队的选择,用群决策协同网络信息模型进行了掩护机编队的选择。首先,给出了协同网络、模糊数和语言变量的相关概念;其次,分析了掩护机编队选择的指标体系框架和协同网络信息框架;然后,构建了群决策协同网络信息的数学模型,在此基础上,给出了方案选择的步骤;最后,运用该模型对掩护机编队的选择进行求解。结果表明：该模型能够综合群体专家的知识,解决掩护机编队选择中的定性判断问题。该模型可用于个体指标和协同指标均为定性指标时的方案优选问题。     

也谈期刊编辑选题策划

期刊编辑选题策划是编辑在信息传播过程中所从事的决策与设计性工作 ,它具有显著的特征 ,应遵循内在的原则。     

Discriminating between the Weibull and log‐normal distributions

Log‐normal and Weibull distributions are the most popular distributions for modeling skewed data. In this paper, we consider the ratio of the maximized likelihood in choosing between the two distributions. The asymptotic distribution of the logarithm of the maximized likelihood ratio has been obtained. It is observed that the asymptotic distribution is independent of the unknown parameters. The asymptotic distribution has been used to determine the minimum sample size required to discriminate between two families of distributions for a user specified probability of correct selection. We perform some numerical experiments to observe how the asymptotic methods work for different sample sizes. It is observed that the asymptotic results work quite well even for small samples also. Two real data sets have been analyzed. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

基于模糊层次分析法的航天测控方案优选决策

分析了航天测控任务重要度的影响因素,运用模糊层次分析法研究了航天测控任务方案的优选决策问题,详细分析了方案重要度排序的计算步骤,并通过实例计算证明了方法的简单可行性,该方法在处理航天测控冲突时有一定的应用价值。