Optimal stopping in software testing

In this paper we address the problem of how to decide when to terminate the testing/modification process and to release the software during the development phase. We present a Bayesian decision theoretic approach by formulating the optimal release problem as a sequential decision problem. By using a non‐Gaussian Kalman filter type model, proposed by Chen and Singpurwalla (1994), to track software reliability, we are able to obtain tractable expressions for inference and determine a one‐stage look ahead stopping rule under reasonable conditions and a class of loss functions. © 2002 Wiley Periodicals, Inc. Naval Research Logistics, 2003     

调运问题中基于栅格模型的快速路径规划方法

针对调运路径规划这一问题,采用栅格模型表示环境地图,通过设定路径搜索方向权重,剔除不必要的搜索区域,提高了搜索效率.仿真结果表明,该算法能有效地提高路径搜索效率,并能搜索到最优路径.     

基于遗传算法的湿陷性黄土地基灰土挤密桩优化设计

利用Visual C＋＋语言,定义了一个面向对象的基于实数编码遗传算法类。运用可最大限度保证遗传算法搜索到问题的全局最优解的深度搜索策略,编制了灰土挤密桩的优化设计和造价估算遗传算法程序,并针对兰州某地灰土挤密桩复合地基进行了计算分析,并与原有方案比较,结果表明：两种优化方案在满足承载力和变形的条件下,在降低造价成本方面优势非常明显。     

随机动态规划的混合算法研究

针对随机条件下动态规划模型的主要特点,运用智能算法混合编程理论,设计了一种探索多阶段决策问题的智能混合算法.该算法首先将问题转化成一族同类型的一步决策子问题,然后利用随机模拟和遗传算法,依据训练样本形成的训练神经元网络,在单步决策中寻求最优策略和最优目标值,逐个求解,再据初始状态逆序求出最优策略序列和最优目标值.仿真结果表明,该算法具有一定的通用性,初始设计点可以随机产生,其计算精度不因函数的非线性强弱而受影响,对目标和约束的限制较少,可应用于多种形式的随机多阶段决策优化问题,较好地满足了随机动态规划模型求解和优化的要求.     

To wait or not to wait: Optimal ordering under lead time uncertainty and forecast updating

There has been a dramatic increase over the past decade in the number of firms that source finished product from overseas. Although this has reduced procurement costs, it has increased supply risk; procurement lead times are longer and are often unreliable. In deciding when and how much to order, firms must consider the lead time risk and the demand risk, i.e., the accuracy of their demand forecast. To improve the accuracy of its demand forecast, a firm may update its forecast as the selling season approaches. In this article we consider both forecast updating and lead time uncertainty. We characterize the firm's optimal procurement policy, and we prove that, with multiplicative forecast revisions, the firm's optimal procurement time is independent of the demand forecast evolution but that the optimal procurement quantity is not. This leads to a number of important managerial insights into the firm's planning process. We show that the firm becomes less sensitive to lead time variability as the forecast updating process becomes more efficient. Interestingly, a forecast‐updating firm might procure earlier than a firm with no forecast updating. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009     

What you should know about approximate dynamic programming

Approximate dynamic programming (ADP) is a broad umbrella for a modeling and algorithmic strategy for solving problems that are sometimes large and complex, and are usually (but not always) stochastic. It is most often presented as a method for overcoming the classic curse of dimensionality that is well‐known to plague the use of Bellman's equation. For many problems, there are actually up to three curses of dimensionality. But the richer message of approximate dynamic programming is learning what to learn, and how to learn it, to make better decisions over time. This article provides a brief review of approximate dynamic programming, without intending to be a complete tutorial. Instead, our goal is to provide a broader perspective of ADP and how it should be approached from the perspective of different problem classes. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009     

基于任意分布随机Petri网的装备维修保障建模与分析

通过将任意分布随机Petri网的基本理论和算法应用到装备维修保障的建模与分析,建立了维修保障系统的任意随机Petri网模型,实现了随机Petri网中变换概率服从指数分布的限制.根据实际系统中相关数据的统计分析和经验估计,以便为利用矩姆函数分析方法对维修保障系统的性能进行分析,为维修保障决策层提供参考,获得了一些有价值的性能指标信息.     

基于背景建模和前景建模的红外运动检测

为抑制了红外图像信噪比低、非静止背景等引起的虚警产生,将基于背景建模和前景建模运动检测(BM-FM)算法引入红外面目标检测中;为抑制因目标与背景对比度低引起的部分目标区域漏检,提出了基于空间邻域信息的前景建模方法(SNFM),利用前一帧图像在像素点邻域内的前景目标点为样本,用核密度估计进行前景建模.试验表明了基于该前景建模方法的BM-FM算法的有效性.     

自行火炮扭力轴载荷谱的测量及疲劳寿命预测

为预测自行火炮扭力轴寿命,对某型自行火炮在不同工况下进行实车试验,获得了多工况下扭力轴的载荷谱。受力分析表明,表面最大拉应力是扭力轴的破坏应力;提出基于随机响应面对扭力轴寿命进行预测的方法,将低周疲劳寿命表达式中的随机参数表示为标准随机变量,引人随机响应的Hermite多项展开式进行拟合,建立了扭力轴疲劳寿命的显式函数。通过对实测载荷谱进行统计分析,依据寿命表达式可以预测扭力轴疲劳寿命,并给出概率分布。该方法弥补了传统响应面法以一般多项式拟合时不能保证收敛性的缺陷。     

舰机协同海上搜寻关键问题研究?

直升机应用于海上搜救可以大大提高搜救速度和成功率。针对水面舰船和直升机的使用特点,分析了在海上搜救中实施舰机协同的必要性,研究了直升机在水面舰船协同下实施海上搜寻的搜寻方式,建立了直升机与舰船协同机动的数学模型,对实际的海上搜寻工作具有较高的实用价值。