柴油机检测与诊断系统的研制

本文以作者参加研制的柴油机检测与诊断系统为对象,在分析柴油机故障机理及特点的基础上,详细论述了检测与诊断系统的组织与结构,检测参数的选择与取舍,信号数据的采集与处理和系统故障诊断等方面的问题。文章着重论述了转速的测量及其在柴油机检测与诊断系统中的应用,柴油机高压油路的检测与诊断,ＤＳＰ系统软件的开发及其在柴油机表面振动诊断中的应用。     

关于空投反潜鱼雷最佳入水点的探讨

“观测—定位—决策”组成了航空反潜作战的一个战术周期。高效率的反潜作战除了加速决策过程,缩短决策周期之外,还体现在选择一个最佳的决策方案中。其中,最佳入水点的选择就是一个重要的决策问题。本文在充分考虑空投鱼雷反潜特点基础上,分两种情况从理论上探讨了反潜鱼雷最佳入水位置和投雷入水方位。     

价值工程在引信方案论证中的应用

本文结合我国引信产品方案论证的实际,论述了应用价值工程原理,综合考虑引信战术性能、可靠性、安全性、寿命、费用等进行引信方案论证的方法、步骤和原则。     

Evasion policies for a vessel being chased by pirate skiffs

Piracy attack is a serious safety problem for maritime transport worldwide. Whilst various strategic actions can be taken, such as rerouting vessels and strengthening navy patrols, this still cannot completely eliminate the possibility of a piracy attack. It is therefore important for a commercial vessel to be equipped with operational solutions in case of piracy attacks. In particular, the choice of a direction for rapidly fleeing is a critical decision for the vessel. In this article, we formulate such a problem as a nonlinear optimal control problem. We consider various policies, such as maintaining a straight direction or making turns, develop algorithms to optimize the policies, and derive conditions under which these policies are effective and safe. Our work can be used as a real‐time decision making tool that enables a vessel master to evaluate different scenarios and quickly make decisions.     

一种基于TF·IEF模型的在线新闻事件探测方法

空间电磁编队具有不消耗推进剂、无羽流污染、连续可逆和同步控制等优势,静态电磁编队在光学干涉成像等领域具有广阔应用前景。动力学平衡态的稳定性与控制是实现静态电磁编队的基础。论文针对双星电磁编队沿径向、切向和法向分布的三种平衡态构形,利用Kane方法建立了6-DOF耦合非线性动力学模型,分析了三种平衡态构形的开环稳定性、耦合特性与控制需求,最后设计LQR控制器,实现了平衡态构形的稳定控制,并进行了仿真验证。     

Estimating the lead-time demand distribution for an autocorrelated demand by the pearson system and a normal approximation

The exact first four moments of lead-time demand L are derived for an AR(1) and a MA(1) demand structures where the arbitrary lead-time distribution is assumed to be independent of the demand structure. These moments then form a basis for the Pearson curve-fitting procedure for estimating the distribution of L. A normal approximation to L, a version of the central limit theorem, is obtained under some general conditions. Reorder points (ROPs) of an inventory system are then estimated based on the Pearson system and a normal approximation. Their performances are evaluated. Numerical investigation shows that the Pearson system performs extremely well. The normal approximation, however, is good only for some limited cases, and is sensitive to the choice of the lead-time distribution. A possible improvement is noted.     

机动式指挥自动化系统电磁兼容性设计

电磁兼容性设计是机动式指挥自动化系统的重要环节。电磁屏蔽、滤波、接地等技术是电磁兼容性设计的重要方法。电磁屏蔽是抑制辐射干扰的一种有效隔离方法。滤波是抑制传导干扰最直接、最有效的方法,对于瞬态脉冲干扰,最有效的办法是采用脉冲吸收技术。接地的综合考虑,对产品电磁兼容性有至关重要的意义。针对机动式指挥自动化系统的结构和组成特点,给出了一些具体的电磁干扰抑制设计,对满足实际的电磁兼容性方面作出了有意义的尝试。     

美军军法官制度简介

美军的政治性工作一般由两“师”完成,一个是牧师,另一个则是随军律师。而随军律师是处理法律问题的军官的泛称,主要指的就是军法官(JudgeAdvocate)和其领导下的法律助手、律师等。2003年的伊拉克战争中,美军约有103位军法官、62名法律专职助手深入战场。①他们在拘押战犯,发表对外声明,与英军建立联合军事司法系统和提供交战规则,促使官兵遵守国际战争法、军事行动法上起了相当大的作用。一、起源与概念在美军中没有法律战的明确词汇和概念,但是这并不意味着美军不运用法律武器以达到军事目的。相反,他们相当擅长和重视这一工作,而且已有…     

椭圆型方程曲线网格的快速生成方法

本文在用椭圆型方程的网格生成方法生成曲线网格时,通过比较四种常用的计算格式,得到了收敛速度较快的生成方法。在计算流体力学领域,对于边界形状随时间变化的流动问题的数值计算,及自适应网格的生成等同题,生成网格的收敛速度直接影响流场的计算速度。在上述情况下使用本文的结果,能有效的减少机时,提高计算效率。     

Workload distribution of discrete‐time parallel queues with two servers

We study discrete‐time, parallel queues with two identical servers. Customers arrive randomly at the system and join the queue with the shortest workload that is defined as the total service time required for the server to complete all the customers in the queue. The arrivals are assumed to follow a geometric distribution and the service times are assumed to have a general distribution. It is a no‐jockeying queue. The two‐dimensional state space is truncated into a banded array. The resulting modified queue is studied using the method of probability generating function (pgf) The workload distribution in steady state is obtained in form of pgf. A special case where the service time is a deterministic constant is further investigated. Numerical examples are illustrated. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 440–454, 2000