求解武器目标分配问题的改进粒子群算法

在建立多种类型武器目标分配模型的基础上,提出了一种求解该模型的改进粒子群算法。首先,定义粒子聚焦距离变化率,使惯性权重依据聚焦距离变化率自适应调整;其次,采用速度最大值线性递减的策略平衡算法收敛精度与全局寻优能力之间的矛盾;最后,粒子替换策略使算法改善了因自适应惯性权重的引入而造成收敛速度变慢的问题。仿真结果表明,提出模型和算法合理有效,算法收敛快,适合求解各种种群规模的武器目标分配问题。     

基于NMPC的战斗机末端机动规避策略

利用非线性模型预测控制（nonlinear model predictive control,NMPC）的思想建立了战机末端规避导弹的机动策略求解方法。根据导弹与战机的空战态势,建立了导弹与战机的相对运动微分方程;将导弹的导引律引入到导弹运动模型中,与飞机模型一起构建了系统预测模型,并对飞机和导弹的运动约束进行了分析。通过对导弹结构限制和战术特性的分析,给出了飞机机动规避导弹的性能指标,进而建立了机动规避导弹的最优控制模型。利用高斯伪谱法对模型进行求解,采用滚动优化策略实现了对机动规避策略的闭环求解。针对导弹气动参数和导航比未知以及相对测量量具有噪声的问题,利用极大似然法对导弹的气动参数和导航比进行估计,实现了对系统预测模型的反馈校正。仿真结果表明,此方法能够实现对导弹的机动规避。     

基于目标满意度的舰载直升机保障能力评估

针对目前我国舰载直升机保障能力评估方面存在数据不完整、评估指标权重不确定的问题,研究了基于目标满意度的舰载直升机保障能力评估方法。通过调研并参考陆基直升机的保障经验,构建了舰载直升机保障能力评估指标体系;在原始样本数据的基础上,以区间数形式给出权重范围,利用满意度模型对权重进行优化,最终得出评估结果,解决了在部分权重信息下、以满意度为评估目的的评估问题。实例分析表明:该方法实用性较强,适用于现阶段舰载直升机保障能力评估问题,具有一定的应用价值。     

地磁导航旋回法自差校正系数的适用性研究

针对地磁导航系统,从直感式地磁导航系统的自差分析出发,解出直感式地磁导航系统的自差校正公式与舰艇纵横摇倾角之间的关系,并分析了纵横摇测量误差对于最后磁航向的影响,以及在潜艇正常的纵横摇范围内自差校正公式中系数的稳定性,即研究了地磁导航旋回法自差校正系数的适用性以达到提高地磁导航精度的目的。对于舰船地磁导航,尤其是对隐蔽性要求比较高的潜艇,具有现实的指导意义。     

Deterministic and stochastic scheduling with teamwork tasks

We study a class of new scheduling problems which involve types of teamwork tasks. Each teamwork task consists of several components, and requires a team of processors to complete, with each team member to process a particular component of the task. Once the processor completes its work on the task, it will be available immediately to work on the next task regardless of whether the other components of the last task have been completed or not. Thus, the processors in a team neither have to start, nor have to finish, at the same time as they process a task. A task is completed only when all of its components have been processed. The problem is to find an optimal schedule to process all tasks, under a given objective measure. We consider both deterministic and stochastic models. For the deterministic model, we find that the optimal schedule exhibits the pattern that all processors must adopt the same sequence to process the tasks, even under a general objective function GC = F(f₁(C₁), f₂(C₂), … , f_n(C_n)), where f_i(C_i) is a general, nondecreasing function of the completion time C_i of task i. We show that the optimal sequence to minimize the maximum cost MC = max f_i(C_i) can be derived by a simple rule if there exists an order f₁(t) ≤ … ≤ f_n(t) for all t between the functions {f_i(t)}. We further show that the optimal sequence to minimize the total cost TC = ∑ f_i(C_i) can be constructed by a dynamic programming algorithm. For the stochastic model, we study three optimization criteria: (A) almost sure minimization; (B) stochastic ordering; and (C) expected cost minimization. For criterion (A), we show that the results for the corresponding deterministic model can be easily generalized. However, stochastic problems with criteria (B) and (C) become quite difficult. Conditions under which the optimal solutions can be found for these two criteria are derived. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

Scheduling recurrent construction

A problem we call recurrent construction involves manufacturing large, complex, expensive products such as airplanes, houses, and ships. Customers order configurations of these products well in advance of due dates for delivery. Early delivery may not be permitted. How should the manufacturer determine when to purchase and release materials before fabrication, assembly, and delivery? Major material expenses, significant penalties for deliveries beyond due dates, and long product makespans in recurrent construction motivate choosing a release timetable that maximizes the net present value of cash flows. Our heuristic first projects an initial schedule that dispatches worker teams to tasks for the backlogged products, and then solves a series of maximal closure problems to find material release times that maximize NPV. This method compares favorably with other well‐known work release heuristics in solution quality for large problems over a wide range of operating conditions, including order strength, cost structure, utilization level, batch policy, and uncertainty level. Computation times exhibit near linear growth in problem size. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

Parametric inference for component distributions from lifetimes of systems with dependent components

In system reliability analysis, for an n ‐component system, the estimation of the performance of the components in the system is not straightforward in practice, especially when the components are dependent. Here, by assuming the n components in the system to be identically distributed with a common distribution belonging to a scale‐family and the dependence structure between the components being known, we discuss the estimation of the lifetime distributions of the components in the system based on the lifetimes of systems with the same structure. We develop a general framework for inference on the scale parameter of the component lifetime distribution. Specifically, the method of moments estimator (MME) and the maximum likelihood estimator (MLE) are derived for the scale parameter, and the conditions for the existence of the MLE are also discussed. The asymptotic confidence intervals for the scale parameter are also developed based on the MME and the MLE. General simulation procedures for the system lifetime under this model are described. Finally, some examples of two‐ and three‐component systems are presented to illustrate all the inferential procedures developed here. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

主被动传感器异地配置下的航迹关联

在雷达和电子支援(ESM)传感器异地配置的情况下,提出了一种基于位置统计量和最大似然准则的异类传感器航迹关联算法。首先基于位置统计量对目标进行了航迹粗关联,排除掉一些虚假关联组合;然后采用最大似然准则对目标进行了航迹细关联,以求进一步提高雷达和ESM传感器航迹关联的检测概率。仿真结果表明,该算法能够快速、准确地完成对多目标的航迹关联。     

成败型产品的Bayes鉴定试验方案研究

利用可靠性增长模型给出了成败型产品鉴定试验的一种Bayes方法.提出了Bayes鉴定试验的最大后验风险准则,利用这种准则制定的鉴定试验方案综合了产品研制过程中的先验信息.在确保产品质量的前提下,与传统的鉴定试验方案相比,将大大节省试验时间.     

混合指数分布模型的Bayes分析

针对截尾试验数据的情况,给出了二元混合指数分布模型的平均寿命和可靠性函数的严格的Ｂａｙｅｓ点估计,并运用最大熵准则给出了可靠性函数的近似的Ｂａｙｅｓ置信下限估计。