一种基于细胞动力学的双目匹配方法

双目匹配是计算机立体视觉的一个难点。以往的各种模型把注意力集中于将左视图像和右视图像中的要素特征唯一地进行双目匹配的任务上。有别于以往的这些模型，文章在ＦＡＣＡＤＥ模型框架的基础上，利用细胞动力学模型隐含了竞争和合作这一原理，实现了一个采用“方位合作，视差竞争”方法的双目匹配模型，从而探索一条利用生物视觉原理进行计算机立体视觉研究的可行途径。     

Bayes 试验分析中验前分布的表示

结合武器系统试验鉴定中的问题，研究Ｂａｙｅｓ方法运用中的验前信息表示问题。文中运用自助（Ｂｏｏｔｓｔｒａｐ）方法和随机加权法确定验前分布。对于多种信息源之下的验前信息，给出了验前分布的融合估计。对当前工程实践中常用的方法及存在的问题，提出了看法和处置方法。     

导弹攻防对抗作战效能仿真分析方法论

本文介绍了在基于攻防对抗仿真的导弹作战效能分析时应该面对的四个主要环节，提出了采用攻防对抗仿真进行导弹作战效能分析的一般过程。该方法适用于各类导弹等武器系统攻防对抗仿真作战效能研究。     

分布式间歇干扰下基于SMI的GNSS空时自适应处理器性能分析

针对全球导航卫星系统接收机面临的分布式间歇干扰威胁,全面准确地分析了基于采样矩阵直接求逆方法的空时自适应处理(space-time adaptive processing, STAP)的抗干扰性能。在建立性能分析模型的基础上,根据间歇干扰造成的采样协方差矩阵不匹配情况,通过分类评估、梳理归纳、理论推导全面分析了不同情况下STAP的性能。分析结果表明在采样长度小于闪烁周期且使用预采用处理方法时,空时自适应处理器会出现漏采样,干扰抑制性能会急剧下降,漏采样出现的频率为各干扰闪烁频率之和。数值和仿真分析验证了理论分析的结果,在此基础上讨论了考虑分布式间歇干扰时STAP的优化设计。     

发射车多轴连通式油气悬架的连通耦合效应

重载导弹发射车多使用4轴连通式双气室油气悬架,为了研究其连通耦合效应,以便对发射车设计进行参考。在2轴连通式油气悬架数学模型的基础上,基于AMESim软件分别建立2轴/4轴连通式双气室油气悬架系统的仿真模型,在几种不同信号频率与相位激励下分析了多轴连通式双气室油气悬架系统的连通耦合效应影响。结果表明:连通式油气悬架在低频激励作用下具有明显的阻尼特性。4轴连通式悬架系统与2轴连通式悬架系统相比,其外特性具备明显优势。连通式油气悬架系统受低频激励时外特性表现比较激烈,而在受高频激励时外特性表现良好,这说明系统在处于高频环境时更能衰减系统的不同步振动。     

双箭头负泊松比结构抗侵彻性能

采用数值模拟方法研究了双箭头负泊松比多胞结构抗子弹侵彻性能,对比分析了顶边撞击、铰点撞击、侧边撞击三种弹靶作用条件下子弹的侵彻行为与双箭头负泊松比结构的破坏形式。研究结果表明:当子弹以较高速度撞击双箭头负泊松比结构时,该结构的负泊松比效应不显著;顶边撞击与铰点撞击时,子弹直接贯穿结构,胞元破坏较小,此时双箭头负泊松比多胞结构抗侵彻性能较差;侧边撞击时,子弹未贯穿多胞结构,胞元破坏较大,双箭头负泊松比结构依靠其双三角结构使子弹发生偏转,显著增大了其侵彻阻力。分析了顶边撞击时子弹的入射角度变化对于双箭头负泊松比结构抗侵彻性能的影响,发现存在30°入射角和60°入射角。当子弹处于这两种入射角附近时,双箭头负泊松比多胞结构具有一定的抗侵彻能力。     

Ordering policies for an inventory system with three supply modes

This article explores ordering policies for inventory systems with three supply modes. This model is particularly interesting because the optimal ordering decision needs to balance the inventory and purchase costs, as well as the costs for earlier and later periods. The latter cost trade-off is present only in inventory systems with three or more supply modes. Therefore, the result not only offers guidelines for the operation of the concerned inventory systems, but also provides valuable insight into the complex cost trade-offs when more supply modes are available. We assume that the difference between the lead times is one period, and the inventory holding and shortage costs are linear. We analyze two cases and obtain the structure of the optimal ordering policy. Moreover, in the first case, explicit formulas are derived to calculate the optimal order-up-to levels. In the second case, although the optimal order-up-to levels are functions of the initial inventory state and are not obtained in closed form, their properties are discussed. We also develop heuristic ordering policies based on the news-vendor model. Our numerical experiments suggest that the heuristic policies perform reasonably well. © 1996 John Wiley & Sons, Inc.     

Analysis of a two-component series system with a geometric process model

In this article, a geometric process model is introduced for the analysis of a two-component series system with one repairman. For each component, the successive operating times form a decreasing geometric process with exponential distribution, whereas the consecutive repair times constitute an increasing geometric process with exponential distribution, but the replacement times form a renewal process with exponential distribution. By introducing two supplementary variables, a set of partial differential equations is derived. These equations can be solved analytically or numerically. Further, the availability and the rate of occurrence of failure of the system are also determined. © 1996 John Wiley & Sons, Inc.     

Discrete bathtub failure rate and upside-down bathtub mean residual life

The concepts of a bathtub-shaped failure rate and upside-down bathtub-shaped mean residual life for discrete lifetime distributions are considered. The relationship between these concepts is established. The discrete counterparts of IFRA and DFRA classes discussed in the continuous case are combined into the class of a bathtub-shaped failure rate average. The relationship between bathtub-shaped failure rate and bathtub-shaped failure rate average is also given. © 1993 John Wiley & Sons, Inc.     

润滑脂氧化安定性的伏安法测定

应用伏安法测定了润滑脂中的抗氧剂含量,研究了润滑脂的氧化安定性和储存安定性与抗氧剂含量的关系。发现润滑脂在储存过程中抗氧剂的消耗是有规律的,开始阶段抗氧剂消耗较慢,一定时间后抗氧剂消耗突然加快,这一结果为指导润滑脂储存提供了科学依据。