可压缩流动压力修正方程分析

依据Ｐａｔａｎｋａｒ提出的差分方程稳定性判断的４项基本法则,对可压缩流动的压力修正方程进行了分析,得出压力修正方程系数为正的条件．指出在每一次求解压力修正方程时必须提高解的收敛程度,以保证下一次迭代的差分方程矩阵接近主对角占优．分析了速度离散方程的欠松驰因子对可压缩流压力修正方程的影响．     

基于一种模型的中子星结构

从物态方程出发,利用中子星结构方程计算了中子星的结构。得到了引力质量材M_G=1.27M_θ材,转动惯量I=1.29x10(45)g/cm~2,与观测结果符合较好。     

高斯定理及安培环路定理的严格证明

在电磁学中,库仑定律和比奥—萨伐尔定律是基本定律,而高斯定理和安培环路定理实用性更强,应用更方便。在一般教科书中,这两个定理(律)的推导都是先取特例,然后再推广到一般情况。本文用数学方法从库仑定律和比奥—萨伐尔定律直接导出这两个定律。     

含非线性半群的微分包含

研究了形如X＇（t）∈-Ax（t）＋F（t,x（t））,0≤t≤T,X（0）＝x0的微分包含解的存在的局部性和整体性的结果,并在某种条件下研究了解的稳定性。     

基于双重酉滤波的再入目标实时跟踪

适当的运动模型和估计方法是提高再入目标跟踪性能的关键.选择机动再入动力学模型,将再入目标跟踪问题转化为状态和参数的联合估计问题,并利用试验数据分析了再入模型状态和参数的相关性.针对原始双重酉滤波算法的确定性系统输入假设造成信息损失的局限性,提出了一种基于随机性系统输入假设的改进双重酉滤波算法,并从理论上分析了该算法的估...     

Coherent systems based on sequential order statistics

The sequential order statistics (SOS) are a good way to model the lifetimes of the components in a system when the failure of a component at time t affects the performance of the working components at this age t. In this article, we study properties of the lifetimes of the coherent systems obtained using SOS. Specifically, we obtain a mixture representation based on the signature of the system. This representation is used to obtain stochastic comparisons. To get these comparisons, we obtain some ordering properties for the SOS, which in this context represent the lifetimes of k‐out‐of‐n systems. In particular, we show that they are not necessarily hazard rate ordered. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

Periodic review inventory management with contingent use of two freight modes with fixed costs

We study a stochastic inventory model of a firm that periodically orders a product from a make‐to‐order manufacturer. Orders can be shipped by a combination of two freight modes that differ in lead‐times and costs, although orders are not allowed to cross. Placing an order as well as each use of each freight mode has a fixed and a quantity proportional cost. The decision of how to allocate units between the two freight modes utilizes information about demand during the completion of manufacturing. We derive the optimal freight mode allocation policy, and show that the optimal policy for placing orders is not an (s,S) policy in general. We provide tight bounds for the optimal policy that can be calculated by solving single period problems. Our analysis enables insights into the structure of the optimal policy specifying the conditions under which it simplifies to an (s,S) policy. We characterize the best (s,S) policy for our model, and through extensive numerical investigation show that its performance is comparable with the optimal policy in most cases. Our numerical study also sheds light on the benefits of the dual freight model over the single freight models. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

基于层次分析法的桂西北古村寨火灾风险评估研究

应用层次分析法,根据桂西北古村寨的实际情况,建立了桂西北古村寨的火灾风险评估体系。采用专家打分法获取数据,并应用统计学中的众值原理,对获得的数据进行了统计,得到了指标的权重,建立了适用于实际情况的消防安全检查表。并应用实例证明了这种评估方法行之有效。     

海警刑事执法存在的问题及对策研究

自2007年《公安机关海上执法工作规定》正式实施以来,公安海警部队已成为打击海上违法犯罪活动,维护海上治安秩序的重要力量。但是,由于海警部队承接海上案件侦查工作时间尚短,经验不足,执法工作仍存在许多问题,已严重影响了海警部队海上刑事执法工作的正常开展。以海警部队海上刑事执法实践中所暴露出的问题为切入点,深刻剖析产生这些问题的原因,并进而提出解决问题的思路与对策,以期对海警部队的海上刑事执法工作提供一定的理论参考,使海警部队在维护我国海洋秩序中发挥更为重要的作用。     

我国周边安全形势对边防工作的影响及应对策略

边防工作作为国防的重要组成部分,涉外性强,受周边安全形势影响大。当前,我国的边防工作既面·l盏着难得的发展机遇,同时更要直面各种挑战。分析周边安全环境对我国边防的影响,可以使我们更好地认清形势,趋利避害,抓住机遇,充分发挥职能作用,确保边防安全稳定。