软件可靠性分配的遗传模型研究

对软件可靠性分配的遗传模型进行了研究,结合相关知识缩小了基本遗传算法的搜索区域,比较灵活地处理了非线性约束条件,提高了搜索效率,避免了早熟收敛现象.此外,在基本遗传算法中增加了保优操作,从而能够在理论上保证实现分配的最优化.算例表明,该算法十分有效.     

对失控翻滚目标任意位置悬停的模糊控制

针对失控翻滚目标任意位置悬停的控制问题进行研究。在目标器轨道坐标系下建立任意偏心率的三维相对运动方程,并分析失控翻滚目标的姿态运动特性。将悬停问题解耦为三个通道的二维模糊控制问题,并以x通道为例进行Mamdani型模糊控制器设计。确定相应的模糊子集、隶属度函数以及模糊控制规则表,采用面积中心法解模糊化。通过数值仿真验证了模糊控制器的控制性能。     

Level workforce planning for multistage transfer lines

In this article, we define two different workforce leveling objectives for serial transfer lines. Each job is to be processed on each transfer station for c time periods (e.g., hours). We assume that the number of workers needed to complete each operation of a job in precisely c periods is given. Jobs transfer forward synchronously after every production cycle (i.e., c periods). We study two leveling objectives: maximin workforce size () and min range (R). Leveling objectives produce schedules where the cumulative number of workers needed in all stations of a transfer line does not experience dramatic changes from one production cycle to the next. For and a two‐station system, we develop a fast polynomial algorithm. The range problem is known to be NP‐complete. For the two‐station system, we develop a very fast optimal algorithm that uses a tight lower bound and an efficient procedure for finding complementary Hamiltonian cycles in bipartite graphs. Via a computational experiment, we demonstrate that range schedules are superior because not only do they limit the workforce fluctuations from one production cycle to the next, but they also do so with a minor increase in the total workforce size. We extend our results to the m‐station system and develop heuristic algorithms. We find that these heuristics work poorly for min range (R), which indicates that special structural properties of the m‐station problem need to be identified before we can develop efficient algorithms. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 577–590, 2016     

Approximation algorithms for sequential batch‐testing of series systems

We introduce and study a generalization of the classic sequential testing problem, asking to identify the correct state of a given series system that consists of independent stochastic components. In this setting, costly tests are required to examine the state of individual components, which are sequentially tested until the correct system state can be uniquely identified. The goal is to propose a policy that minimizes the expected testing cost, given a‐priori probabilistic information on the stochastic nature of each individual component. Unlike the classic setting, where variables are tested one after the other, we allow multiple tests to be conducted simultaneously, at the expense of incurring an additional set‐up cost. The main contribution of this article consists in showing that the batch testing problem can be approximated in polynomial time within factor , for any fixed . In addition, we explain how, in spite of its highly nonlinear objective function, the batch testing problem can be formulated as an approximate integer program of polynomial size, while blowing up its expected cost by a factor of at most . Finally, we conduct extensive computational experiments, to demonstrate the practical effectiveness of these algorithms as well as to evaluate their limitations. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 275–286, 2016     

对流层散射双向时间比对中对流层斜延迟估计

为精确估计对流层散射双向时间比对系统中对流层斜延迟,分析了估计卫星信号对流层斜延迟的Hopfield天顶延迟模型及CFA2.2映射函数模型并对其进行修正,从而适用于对流层散射斜延迟的精确估计。根据北纬35°~37°范围内的三个测站2010—2012三年的气象数据,验证Hopfield模型精度范围小于35 mm,并将三个测站按相互之间基线距离的不同分为三组比对站,利用2012年的气象数据,计算在不同入射角下一年的对流层散射斜延迟,并得出最大斜延迟对应的年积日和入射角。结果表明,三组比对站的最大单向散射斜延迟为21.82~35.45 m。在双向比对抵消90%的情况下,时间延迟为7.3 ns~11.7 ns;相互抵消95%时,时间延迟为3.6 ns~5.9 ns。     

基于端点梯形白化权函数的飞机保障性灰色评估

保障性评估是提高飞机保障性的有效手段。从保障性的定义出发,构建了飞机保障性评估指标体系,在利用层次分析法(AHP)确定指标权重的基础上,对三角白化权函数进行了改进,建立了基于端点梯形白化权函数灰色评估模型,很好地解决了相邻的若干类别对该类别聚类中心的影响问题,并将其应用于飞机保障性的评估,通过实例分析,验证了此评估方法的可行性,对提升飞机保障性评估的准确性有一定的参考价值。     

基于可用度的电子设备告警系统检查策略研究

针对电子设备告警系统故障具有隐蔽性的特点,考虑检查不完善的因素,运用延迟时间概念,以系统期望可用度最大为优化目标,建立了电子设备隐蔽功能故障检查优化模型。提出了优化检查间隔期的算法,并通过实际案例验证了模型的有效性。     

复杂目标毁伤效果评估关键问题分析

复杂目标毁伤效果评估一直是毁伤效果评估中的重难点问题,作为作战指挥决策的重要依据,对其关键问题进行分析和研究具有重要现实意义。首先总结和梳理复杂目标毁伤效果评估的基本思路,在此基础上归纳出复杂目标毁伤效果评估的一般步骤,并构建毁伤效果评估的基本框架,明确其中的关键环节和问题,并基于现有复杂目标毁伤效果评估的方法和模型对其进行详细的论述和分析,最后指明未来发展的方向。     

水下导弹导引法与弹道仿真

假设目标作直线运动时,以未来方位导引法和自动变提前角导引法两种不同的导引方法为例,建立了水下导弹的线导和自导相对运动方程、导引弹道数学模型并进行了仿真,获得了水下导弹、目标和制导站的相对运动轨迹及水下导弹与目标相对距离随时间变化的曲线和攻击效果。对水下导弹攻击目标距离的预测具有较高的参考价值。     

武器装备作战效能灰色聚类评估

武器装备作战效能的指标是多样的,而且意义不同、量纲不同,且指标的实现值往往在数量上悬殊很大,如何在这种情况下比较好的解决作战效能综合评估问题,提出了基于灰色定权聚类和三角白化权函数的灰色聚类评估方法解决此问题,给出了应用的一般步骤。以某型水陆坦克为例,对其改装前后的作战效能进行了对比分析,并为其将来进一步改进提出了建设性建议。