再生分辨矩阵与决策熵的不完备决策系统属性约简

为了有效地解决不完备决策系统的属性约简问题,提高属性约简的效率,提出了基于再生分辨矩阵与决策熵的不完备属性约简算法。该算法利用基于容差关系的分辨矩阵来计算相对核,通过再生分辨矩阵计算再生集和再生集属性来缩小加入约简集的条件属性选择范围,以再生集属性的分辨度和决策熵为依据,选择加入约简集的条件属性,并通过实例进行验证分析。结果表明,该算法适用于协调不完备决策系统与不协调不完备决策系统,能够有效地降低时间复杂度,并得到最优属性约简。     

天海一体化水下重力辅助导航研究进展

水下航行器精确导航在海洋利用和开发过程中发挥了重要作用。关于抑制水下导航误差随时间累积的问题,进行了详细阐述和分析:简述了惯性器件的发展历程;详细对比了各导航系统的优劣性,着重介绍了国内外重力辅助导航研究现状,分析了针对目前水下航行器高精度导航的需求,以及全球海洋重力基准图空间分辨率不足的科学难题;提出了通过GNSS-R测高星座获得高空间分辨率和高精度全球海洋重力基准图的思路及技术路线,以期提高水下重力辅助导航精度。     

基于系统动力学的防空作战指挥关键因素分析

防空作战指挥效能的高低,对整个防空作战结局有着重要的影响.基于系统动力学的方法对防空作战指挥效能进行评估,分析了影响指挥效能的关键因素.进而提出加强对防空作战指挥不确定决策方法的研究和优化防空作战指挥体制两项对策措施以提高指挥效能.     

基于组合熵权的联合作战目标选择模型研究

针对作战中目标选择与排序问题,分析确定了8种在联合作战条件下影响目标选择关键因素。在此基础上应用多属性决策理论,以组合熵权系数确定指标权重,建立了目标选择模型。模型简洁易于实现,并且在决策中有效减少了主观随意性。最后通过仿真实例说明了模型的有效性和可操作性。     

OLAP技术在器材保障决策支持系统中的应用

为弥补基于模型库和方法库的器材保障决策支持系统的不足,探讨利用OLAP技术处理数据的方法。结果表明,利用OLAP技术从多角度、多侧面观察数据,将为我军器材保障决策的科学化提供强大的支持。     

基于风险评估的检测与修理决策模型

研究了基于故障风险的检测与维修策略，运用威布尔比例风险模型建立系统故障率与工作时间及所处状态的关系。分析了两类基于间接状态信息维修决策的风险，建立了系统检测及维修策略的决策树，通过比较检测与不检测情况下的期望费用确定最优的检测间隔。算例表明，所提出的方法能够有效控制系统运行风险，降低系统运行费用。     

空战机动决策方法研究

在阐述空战机动决策作用的同时 ,分析对比了几种常用空战机动决策方法 :矩阵对策法、专家系统法、神经网络法和微分对策法等 ;在此基础上引入了一种新的空战机动决策方法——决策影响图法 ,并对其具体应用作了探讨。     

基于球面映射和拆卸树的拆卸序列生成算法

拆卸序列生成是虚拟维修的核心之一,直接关系到虚拟维修的可行性及成本。搜索所有可行拆卸序列、避免组合爆炸并保持算法的通用性是序列生成算法的研究难点。通过引入球面映射概念,定义了局部和全局阻碍方向及可拆卸方向,克服了传统方法中基于六坐标轴方向创建干涉矩阵的局限性。提出了一种符合拆卸规则和拆卸关系表的拆卸树生成算法,求得所有可行的拆卸序列,并通过实例在虚拟维修平台上得到了实现。     

On the reduction of total‐cost and average‐cost MDPs to discounted MDPs

This article provides conditions under which total‐cost and average‐cost Markov decision processes (MDPs) can be reduced to discounted ones. Results are given for transient total‐cost MDPs with transition rates whose values may be greater than one, as well as for average‐cost MDPs with transition probabilities satisfying the condition that there is a state such that the expected time to reach it is uniformly bounded for all initial states and stationary policies. In particular, these reductions imply sufficient conditions for the validity of optimality equations and the existence of stationary optimal policies for MDPs with undiscounted total cost and average‐cost criteria. When the state and action sets are finite, these reductions lead to linear programming formulations and complexity estimates for MDPs under the aforementioned criteria.© 2017 Wiley Periodicals, Inc. Naval Research Logistics 66:38–56, 2019     

Maintaining systems with heterogeneous spare parts

We consider the problem of optimally maintaining a stochastically degrading, single‐unit system using heterogeneous spares of varying quality. The system's failures are unannounced; therefore, it is inspected periodically to determine its status (functioning or failed). The system continues in operation until it is either preventively or correctively maintained. The available maintenance options include perfect repair, which restores the system to an as‐good‐as‐new condition, and replacement with a randomly selected unit from the supply of heterogeneous spares. The objective is to minimize the total expected discounted maintenance costs over an infinite time horizon. We formulate the problem using a mixed observability Markov decision process (MOMDP) model in which the system's age is observable but its quality must be inferred. We show, under suitable conditions, the monotonicity of the optimal value function in the belief about the system quality and establish conditions under which finite preventive maintenance thresholds exist. A detailed computational study reveals that the optimal policy encourages exploration when the system's quality is uncertain; the policy is more exploitive when the quality is highly certain. The study also demonstrates that substantial cost savings are achieved by utilizing our MOMDP‐based method as compared to more naïve methods of accounting for heterogeneous spares.