Waypoint analysis for command and control

Command and Control (C2) in a military setting can be epitomized in battles‐of‐old when commanders would seek high ground to gain superior spatial‐temporal information; from this vantage point, decisions were made and relayed to units in the field. Although the fundamentals remain, technology has changed the practice of C2; for example, enemy units may be observed remotely, with instruments of varying positional accuracy. A basic problem in C2 is the ability to track an enemy object in the battlespace and to forecast its future position; the (extended) Kalman filter provides a straightforward solution. The problem changes fundamentally if one assumes that the moving object is headed for an (unknown) location, or waypoint. This article is concerned with the new problem of estimation of such a waypoint, for which we use Bayesian statistical prediction. The computational burden is greater than an ad hoc regression‐based estimate, which we also develop, but the Bayesian approach has a big advantage in that it yields both a predictor and a measure of its variability. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

Numerical investigation of the shockwave overpressure fields of multi-sources FAE explosions

Shockwaves from fuel-air explosive (FAE) cloud explosions may cause significant casualties. The ground overpressure field is usually used to evaluate the damage range of explosion shockwaves. In this paper, a finite element model of multi-sources FAE explosion is established to simulate the process of multiple shockwaves propagation and interaction. The model is verified with the experimental data of a fourfold-source FAE explosion, with the total fuel mass of 340 kg. Simulation results show that the overpressure fields of multi-sources FAE explosions are different from that of the single-source. In the case of multi-sources, the overpressure fields are influenced significantly by source scattering distance and source number. Subsequently, damage ranges of overpressure under three different levels are calculated. Within a suitable source scattering distance, the damage range of multi-sources situation is greater than that of the single-source, under the same amount of total fuel mass. This research provides a basis for personnel shockwave protection from multi-sources FAE explosion.     

基于深度强化学习的无人战车自主行为决策

针对高动态强对抗战场环境下,无人战车面临的自主行为决策问题,分析了未来陆战场无人战车实际作战需求,构建了基于马尔可夫决策过程的自主行为决策模型,提出了一种深度强化学习结合行为树的方法,利用行为树的逻辑规则与先验知识降低强化学习问题的难度,保证收敛性和鲁棒性,同时使行为决策模型具有学习能力.构建典型作战场景,验证深度强化学习结合行为树的无人战车自主行为决策方法的有效性.     

扭杆式坦克悬挂系统的强度分析

针对目前悬挂系统设计理论的不足,运用工程力学中的卡氏第二定理和莫尔法求出负重轮行程与所受载荷之间的理论关系,并考虑了平衡肘的变截面对应力状态的影响,进而得到系统内关键点处的应力值;在理论分析的基础上,由简单到复杂,分别建立了初步模型、修正模型和最终的实体模型.应用有限元软件对悬挂系统进行三维数值模拟,计算了悬挂系统的应力场和位移场.理论分析和数值模拟的结果表明:悬挂系统力学模型较好地描述了悬挂系统的实际情况;有限元计算模型对于扭杆式悬挂系统强度计算非常有效,所得应力集中区与实际失效情况基本一致;应用本研究结果,可对悬挂系统作进一步的疲劳分析.     

Approximating nondominated sets in continuous multiobjective optimization problems

Many important problems in Operations Research and Statistics require the computation of nondominated (or Pareto or efficient) sets. This task may be currently undertaken efficiently for discrete sets of alternatives or for continuous sets under special and fairly tight structural conditions. Under more general continuous settings, parametric characterisations of the nondominated set, for example through convex combinations of the objective functions or ε‐constrained problems, or discretizations‐based approaches, pose several problems. In this paper, the lack of a general approach to approximate the nondominated set in continuous multiobjective problems is addressed. Our simulation‐based procedure only requires to sample from the set of alternatives and check whether an alternative dominates another. Stopping rules, efficient sampling schemes, and procedures to check for dominance are proposed. A continuous approximation to the nondominated set is obtained by fitting a surface through the points of a discrete approximation, using a local (robust) regression method. Other actions like clustering and projecting points onto the frontier are required in nonconvex feasible regions and nonconnected Pareto sets. In a sense, our method may be seen as an evolutionary algorithm with a variable population size. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

一种基于重要性权重的证据合成方法及其应用

针对Dempster方法在合成高度冲突证据时结果与直观结论相悖的问题,提出了一种改进的基于重要性权重的证据合成方法,并将其应用到海上目标的识别。首先,根据证据之间的相似性程度判断证据间是否存在冲突,对于有冲突的情形,由基于P距离的权重分配模型得到各证据的重要性权值;然后,对BPA函数进行修正,采用Dempster规则修正后的BPA函数进行合成;最后,利用雷达和舰船的对应关系,将侦察雷达探测到的目标雷达信号载频、脉宽、重频转化为雷达参数的概率分配,并运用改进的证据合成方法进行了目标识别。仿真计算结果证明:该方法能有效处理冲突证据组合,克服了一票否决问题,减小了识别结果的不确定性,并保留了Dempster方法处理非冲突证据组合的良好特性。     

Analysis of a new vehicle scheduling and location problem

We consider a container terminal discharging containers from a ship and locating them in the terminal yard. Each container has a number of potential locations in the yard where it can be stored. Containers are moved from the ship to the yard using a fleet of vehicles, each of which can carry one container at a time. The problem is to assign each container to a yard location and dispatch vehicles to the containers so as to minimize the time it takes to download all the containers from the ship. We show that the problem is NP‐hard and develop a heuristic algorithm based on formulating the problem as an assignment problem. The effectiveness of the heuristic is analyzed from both worst‐case and computational points of view. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 363–385, 2001