Bayesian sampling plans for exponential distributions with interval censored samples

This article studies the problem of designing Bayesian sampling plans (BSP) with interval censored samples. First, an algorithm for deriving the conventional BSP is proposed. The BSP is shown to possess some monotonicity. Based on the BSP and using the property of monotonicity, a new sampling plan modified by the curtailment procedure is proposed. The resulting curtailed Bayesian sampling plan (CBSP) can reduce the duration time of life test experiment, and it is optimal in the sense that its associated Bayes risk is smaller than the Bayes risk of the BSP if the cost of the duration time of life test experiment is considered. A numerical example to compute the Bayes risks of BSP and CBSP and related quantities is given. Also, a Monte Carlo simulation study is performed to illustrate the performance of the CBSP compared with the BSP. The simulation results demonstrate that our proposed CBSP has better performance because it has smaller risk. The CBSP is recommended. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 604–616, 2015     

改进型Voronoi图和动态权值A*算法的无人机航迹规划

针对实际作战环境中的不同威胁等级和不同威胁实体的威胁源,提出了改进型的Voronoi图,并建立了基于改进型Voronoi图的航迹规划空间;基于A*算法的估价函数在不同阶段对指标的敏感度不同,在传统的启发式A*搜索算法基础上提出了动态权值A*搜索算法,提高了航迹搜索的效率,实现了航迹搜索过程快速性和准确性的结合。最后通过Matlab仿真计算出由动态权值A*算法得到的最优航迹,并进行了航迹的平滑处理,仿真表明了该方法的可行性。     

试验训练领域仿真体系结构及研究现状

试验训练领域仿真体系结构的研究对我国国防力量的建设有着重要的作用。对国内以及美国试验训练领域仿真体系结构的研究情况进行了阐述和分析,总结了国内和美国的仿真体系结构的研究现状和出现的问题,并总结了试验训练领域仿真体系结构的发展前景,提出了一些建立仿真体系结构的建议。目前国内有很多单位都在研究试验训练领域仿真体系结构,但是就建立一个完整的仿真体系结构而言,国内还需要更多的努力。相关技术最发达的美国也遇到了一些困难,且可能在以后主推CTIA。     

热图像与瞄准镜分划图像实时叠加处理系统研究

热像仪是夜战中用于观察和瞄准的重要装备,但目前装备的某些坦克和装甲车辆上的热像瞄准镜,本身并不具有瞄准分划,因而也就很难获取目标更多的信息,限制了对目标进行有效的瞄准射击:为了使其热像瞄准镜同样具有坦克微光瞄准镜所具有的功能,作者利用高速数字信号处理器ADsP21535开发评估板,研究设计了热图像和瞄准镜分划图像实时叠加处理系统,从而较好的解决上述问题.     

Newsvendor problems with sequentially revealed demand information

This article analyzes a capacity/inventory planning problem with a one‐time uncertain demand. There is a long procurement leadtime, but as some partial demand information is revealed, the firm is allowed to cancel some of the original capacity reservation at a certain fee or sell off some inventory at a lower price. The problem can be viewed as a generalization of the classic newsvendor problem and can be found in many applications. One key observation of the analysis is that the dynamic programming formulation of the problem is closely related to a recursion that arises in the study of a far more complex system, a series inventory system with stochastic demand over an infinite horizon. Using this equivalence, we characterize the optimal policy and assess the value of the additional demand information. We also extend the analysis to a richer model of information. Here, demand is driven by an underlying Markov process, representing economic conditions, weather, market competition, and other environmental factors. Interestingly, under this more general model, the connection to the series inventory system is different. © 2012 Wiley Periodicals, Inc. Naval Research Logistics 2012     

警报关联图：一种网络脆弱性量化评估的新方法

作为一种基于模型的脆弱性分析技术,攻击图能够识别网络中存在的脆弱性和它们之间的相互关系,分析出可能的攻击路径和潜在威胁.论文在攻击图的基础上提出了警报关联图的概念,利用攻击图中蕴含的脆弱性先验知识,将实时IDS警报信息映射到攻击路径,动态反映攻击进程和攻击者意图.在此基础上提出了一种基于警报关联图的网络脆弱性量化评估方法,通过计算警报关联边的权值对网络脆弱性进行动态分析,这种方法结合了静态的网络脆弱性先验知识和动态变化的攻击者意图,能有效反映网络脆弱性在动态攻击情况下的变化.     

A standardized scan statistic for detecting spatial clusters with estimated parameters

The scan statistic based on likelihood ratios (LRs) have been widely discussed for detecting spatial clusters. When developing the scan statistic, it uses the maximum likelihood estimates of the incidence rates inside and outside candidate clusters to substitute the true values in the LR statistic. However, the parameter estimation has a significant impact on the sensitivity of the scan statistic, which favors the detection of clusters in areas with large population sizes. By presenting the effects of parameter estimation on Kulldorff's scan statistic, we suggest a standardized scan statistic for spatial cluster detection. Compared to the traditional scan statistic, the standardized scan statistic can account for the varying mean and variance of the LR statistic due to inhomogeneous background population sizes. Extensive simulations have been performed to compare the power of the two cluster detection methods with known or/and estimated parameters. The simulation results show that the standardization can help alleviate the effects of parameter estimation and improve the detection of localized clusters. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

Irreducibility of joint inventory positions in an assemble‐to‐order system under (r,nQ) policies

In a typical assemble‐to‐order system, a customer order may request multiple items, and the order may not be filled if any of the requested items are out of stock. A key customer service measure when unfilled orders are backordered is the order‐based backorder level. To evaluate this crucial performance measure, a fundamental question is whether the stationary joint inventory positions follow an independent and uniform distribution. In this context, this is equivalent to the irreducibility of the Markov chain formed by the joint inventory positions. This article presents a necessary and sufficient condition for the irreducibility of such a Markov chain through a set of simultaneous Diophantine equations. This result also leads to sufficient conditions that are more general than those in the published reports. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

基于相关熵的MACH滤波器

最大平均相关高度(MACH:Maximum Average Correlation Height)滤波器是一种重要的基于相关的模式识别方法。滤波器由训练数据线性构造而成,具有良好的畸变容忍能力,在线性高斯噪声条件下具有理论最优性。为将算法适用于广泛的非线性、非高斯情形,本文引入一种新的度量函数相关熵,可隐性地将输入数据通过非线性变换映射到特征空间;并在新的空间中提出了基于相关熵的MACH滤波器构造方法。最后将此方法应用于合成孔径雷达(SAR:Synthetic Aperture Radar)图像目标分类进行了实验,在接收机工作性能曲线和峰值旁瓣比的比对中,本文算法的性能均有所提升。     

坦克实体智能机动路径模型

根据坦克机动作战的一般原则,首先对影响坦克实体机动的因素进行了分析和合理的假设;充分考虑战术模拟中的实际情况,将数字地图中各点间的空间距离转化为以各点间机动时间为权边的网图,通过求任意两点间的最短距离的方法,建立坦克实体机动最短时间路径的数学模型。并给出了人工智能算法,把问题求解过程简化,从而解决战术模拟系统中智能机动中的路径选择问题。