基于近似策略的联合优化方法

针对优化中收敛速度和优化解全局性的问题,提出了一种联合优化方法:构造原问题的近似模型,使用全局优化方法对近似函数进行优化,得到优化点作为初值,再使用局部优化方法对原问题进行优化.为了获得对原问题更好的近似,改进了径向基插值方法,以优化误差的方法来选择参数.利用临近空间机翼模型的优化对算法进行了测试,结果表明,优化参数的...     

有虚拟势能点的编队控制策略

针对人工势能场方法容易陷入局部极值的缺陷,提出了有虚拟势能点的避障算法.该算法在编队进入对队形影响较大的复杂环境中引入额外的虚拟势能点,利用虚拟势能点的作用力使智能体脱离局部障碍物陷阱,进行队形重组,提高了编队队形保持能力;编队运动通过不同的地形时,队形变化程度不一,单一队形控制方法难以在各种环境下保持高效性、有效性,...     

带概率因子的最小费用流经济性分析模型研究

装备跨越式更新换代,传统的备件维修保障模式已难适应装备的发展。针对备件维修级别经济性问题,在备件及其维修网络结构分析的基础上,分析各种维修费用,并借助故障树理论,设定四类模型节点:源节点、修理决策节点、转移概率节点和结束节点;分析建立带概率因子的最小费用流经济性分析的模型网络图,结合概率因子分析各种维修费用,由此建立最小费用流的经济性分析模型,并实例论证了该模型的可行性,为解决备件维修级别问题提供了一种新的思路。     

Optimal pricing and inventory control policy in periodic‐review systems with fixed ordering cost and lost sales

This paper studies a periodic‐review pricing and inventory control problem for a retailer, which faces stochastic price‐sensitive demand, under quite general modeling assumptions. Any unsatisfied demand is lost, and any leftover inventory at the end of the finite selling horizon has a salvage value. The cost component for the retailer includes holding, shortage, and both variable and fixed ordering costs. The retailer's objective is to maximize its discounted expected profit over the selling horizon by dynamically deciding on the optimal pricing and replenishment policy for each period. We show that, under a mild assumption on the additive demand function, at the beginning of each period an (s,S) policy is optimal for replenishment, and the value of the optimal price depends on the inventory level after the replenishment decision has been done. Our numerical study also suggests that for a sufficiently long selling horizon, the optimal policy is almost stationary. Furthermore, the fixed ordering cost (K) plays a significant role in our modeling framework. Specifically, any increase in K results in lower s and higher S. On the other hand, the profit impact of dynamically changing the retail price, contrasted with a single fixed price throughout the selling horizon, also increases with K. We demonstrate that using the optimal policy values from a model with backordering of unmet demands as approximations in our model might result in significant profit penalty. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2006     

试论公安院校实验教学与人才培养

实验教学是培养学生实践能力和创新精神、提高其综合素质的重要环节。其中包括实验教学的总体目标、教学类型、教学内容、教学步骤、教学方法和质量测评等内容。     

多处理机系统中的宏任务并行

多处理机系统是巨型机的发展方向。宏任务是在多处理机系统上用来加快程序执行的一条主要途径。文中介绍了宏任务并行,描述了宏任务的实现,讨论了编译器和操作系统的支持。最后解释了宏任务的一个程序。     

样条函数康特诺维奇法在复合材料板和圆柱曲板弯曲及线性稳定性分析中的应用

样条函数康特诺维奇法是作者首先提出的一种结构数值计算方法。它实质上是一种离散形式的康特诺维奇法,将二维问题化为一维问题,使问题的自由度数大幅度减少。在本文中,基于Mindlin假设,将样条函数康特诺维奇法应用于金属、复合材料单层板及圆柱曲板的弯曲及线性稳定性分析。     

微机数控定比运动速度插补的最小误差法

本文针对微机数控中检测一轴的运动、控制另一轴运动的定比运动,提出了一个控制速度插补的算法,证明了这种方法的最小误差特点,并进行了误差分析。     

Some recent findings in bayesian attribute single and double sampling

This article deals with several items, including theoretical and applied results. Specific topics include (1) a discrete, economically based, attributes acceptance sampling model and its adaptations, (2) relevant costs, (3) relevant prior distributions, (4) comparison of single- and double-sampling results, and (5) reasons for marginal implementation success following excellent implementation efforts. The basic model used is one developed by Guthrie and Johns; adaptations include provisions for fixed costs as well as modifications to permit double sampling. Optimization is exact, rather than approximate. Costs incorporated into the model are for sampling inspection, lot acceptance, and lot rejection. For each of these three categories a fixed cost is included as well as two variable costs, one for each item and the other for each defective item. Discrete prior distributions for the number of defectives in a lot are used exclusively. These include the mixed binomial and Polya distributions. Single- and double-sampling results are compared. Double sampling regularly performs at only slightly lower cost per lot than single sampling. Also, some cost and prior distribution sensitivity results are presented. Comments are provided regarding actual implementation experiences in industry. Practical deficiencies with the Bayesian approach are described, and a recommendation for future research is offered.     

进化计算在机器人轨迹规划中的应用研究

本文介绍了采用进化计算思想研制的机器人轨迹规划系统ＲＴＰ－１，提出多层次动态结构化编码方案，利用低中高三层进化算法分别优化距离、路径和关节角度偏差，基于多层综合优化策略解决多目标多约束工程优化问题，建立了次序相关问题求解的通用框架。在进化算法中，利用拉马克效应加快轨迹规划速度，在ＲＭ－５０１机械手上实现的任意空间直线和空间曲线轨迹规划具有良好的鲁棒性，规划轨迹的相邻臂构型间具有良好的柔顺性，规划轨迹的臂构型序列具有良好的平滑性。本文所采用的机器人轨迹规划方法具有通用性，可推广应用于各种动力学系统的研制。