Patterns in spatial point locations: Local indicators of spatial association in a minefield with clutter

The problem of detecting a minefield in the presence of clutter can be abstracted to that of detecting a spatial pattern within a set of point locations. The point locations are superpositions of several patterns, one of which corresponds to mines. In contrast to previous articles that take a formal, model‐based approach, this article proposes a statistical methodology that is distinctly exploratory. Each point location is considered separately, and its contributions to a global measure of spatial distances between locations are featured. Different patterns and unusual points can be more easily identified on the new scale. Both minefield data and simulated point patterns demonstrate the power of the method. © 2001 John Wiley & Sons, Inc., Naval Research Logistics 48:333–347, 2001     

关于取绝对值的函数可微性的讨论

求绝对值函数的导数是高等数学的一个难点。本文证明了一个公式,能较全面地解决绝对值函数的求导问题。     

子自仿射集的Hausdorff维数

设S1,S2 ,… ,SN 是Rn 上的N个仿射压缩映射 ,若Rn 的紧子集E满足E UNi =1 Si(E) ,则称E为子自仿射集 .作者在一定条件下得到了子自仿射集E的Hausdorff维数 .     

投资消费模型中价值函数的基本性质

在有交易费的投资消费模型下,讨论了价值函数的一些基本性质,即给出了价值函数是有限连续和非减凹函数.     

利用验前信息的一种序贯检验方法——序贯验后加权检验方法

序贯验后加权检验方法是Bayes 统计观点在假设检验中的运用。本文提出了该方法的一般理论,给出了当总体的分布参数具有验前信息时的序贯检验方法。文中确定了决策区的划分,同时讨论了序贯截尾方案,给出了检验中可能犯两类错误的概率的上界,并将一般理论应用于产品的可靠性检验和再入飞行器随机落点的精度鉴定。由于运用了验前信息,因此能有效地在少量试验之下进行统计假设检验。本文所提供的方法对于昂贵产品试验结果的统计评定具有普遍意义。     

基于RBF网络的导弹攻击区解算及对比分析

研究了神经网络在空空导弹攻击区处理中的运用,在提出多层前馈(MF)网络和径向基函数(RBF)网络设计方案的基础上,着重对MF网络的BP算法、改进BP算法以及RBF网络的应用进行了仿真,并从收敛速度、逼近精度和实时性三个方面,对计算结果进行了对比分析,结论表明RBF网络在导弹攻击区处理中具有更高的可行性,更适用于快速高精度的火控解算。     

基于非局部理论的黏弹性基体中压电纳米梁热-机电振动特性

基于非局部Euler梁理论和Hamilton原理建立黏弹性基体中压电纳米梁的热-机电振动特性分析模型。综合考虑非局部效应、压电效应、温度场、电场等复杂因素影响,推导出黏弹性基体中压电纳米梁振动特性分析的振动控制方程,并利用分布参数传递函数方法求解出一般边界条件下压电纳米梁的固有频率及相应振型。以锆钛酸铅压电陶瓷-4材料制成的某压电纳米梁为例,给出了四种典型边界条件下该压电纳米梁的前四阶固有频率,并系统分析了非局部效应、外部电压、温度载荷、黏弹性基体等因素对压电纳米梁热-机电振动特性的影响规律。分析结果表明:所建立的振动特性分析模型及其求解方法在分析黏弹性基体中压电纳米梁的热-机电振动特性问题中准确有效。     

A cost–benefit analysis of terrorist attacks

A cost–benefit analysis of terrorist attacks is developed and placed within a systematic theoretical structure. For the target or object of the attack, we consider the lost value of human lives, lost economic value, and lost influence value, counted as benefits for the terrorist. The corresponding losses for the terrorist are counted as costs. The terrorist attacks if benefits outweigh costs. Bounded rationality is enabled where the three kinds of benefits and costs can be weighted differently. We account for two ex ante probabilities of successful planning and attack, and enable the terrorist to assign different weights to its multiple stakeholders. We introduce multiple time periods, time discounting, attitudes towards risk, and subcategories for the benefits and costs. The cost–benefit analysis is illustrated with the 11 September 2001 attack, and 53 incidents in the Global Terrorism Database yielding both positive and negative expected utilities. The paper is intended as a tool for scientists and policy-makers, as a way of thinking about costs and benefits of terrorist attacks.     

基于灰色聚类的管道电伴热系统安全评价

虽然管道电伴热系统在国防工业领域有着十分广泛的应用,但在实际使用过程中也经常会出现各种问题.本文针对管道电伴热系统安全性的评价问题,在分析总结管道电伴热系统常见故障的基础上,从系统设计、安装施工、电气连接与操作使用4个方面,选取17个影响因素构建管道电伴热系统安全评价指标体系,通过改进层次分析法计算得到各方案层的权重值...     

基于效用分析的武器装备发展方案决策

武器装备发展方案效用决策分析的目的就是以一定的方法和途径,根据决策者对武器装备发展所涉及的各项决策准则的偏好及其对各决策备选方案可能出现风险程度的态度,诱导出决策者对于各项准则的效用函数,从而以诱导的形式综合出各决策备选方案的综合效用,以获得决策者认为是最满意的决策方案.