Heuristics for the location of inspection stations on a network

This article considers the preventive flow interception problem (FIP) on a network. Given a directed network with known origin‐destination path flows, each generating a certain amount of risk, the preventive FIP consists of optimally locating m facilities on the network in order to maximize the total risk reduction. A greedy search heuristic as well as several variants of an ascent search heuristic and of a tabu search heuristic are presented for the FIP. Computational results indicate that the best versions of the latter heuristics consistently produce optimal or near optimal solutions on test problems. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 287–303, 2000     

联合作战目标协同模型构建与求解方法?

在对联合作战目标协同研究内容分析的基础上,提出了多任务部队与多作战目标的协同目标分配模型,其融合了目标综合价值、目标打击有效性、目标威胁适配度、目标类型匹配、目标距离匹配等因素。通过对各因素量化并将协同目标分配模型转换为指派问题进行求解,验证了分析方法的可行性。     

复杂约束下的导弹作战任务规划模型和算法研究*

导弹作战任务规划是一个涉及时间、资源、质量和其他关系约束的复杂问题.首先通过定叉约束满足效用对基本约束满足模型进行了扩展,建立了导弹任务规划的约束满足优化模型.在此基础上,研究了任务规划模型求解的时间和效用传播算法,提出了基于综合效用的优化求解框架.该模型和求解框架易于解决具有多种约束因素的复杂问题,具有较好的通用性.通过定义软、硬约束效用,使得实际任务规划问题求解具有更好的灵活性.     

Concise RLT forms of binary programs: A computational study of the quadratic knapsack problem

The reformulation‐linearization technique (RLT) is a methodology for constructing tight linear programming relaxations of mixed discrete problems. A key construct is the multiplication of “product factors” of the discrete variables with problem constraints to form polynomial restrictions, which are subsequently linearized. For special problem forms, the structure of these linearized constraints tends to suggest that certain classes may be more beneficial than others. We examine the usefulness of subsets of constraints for a family of 0–1 quadratic multidimensional knapsack programs and perform extensive computational tests on a classical special case known as the 0–1 quadratic knapsack problem. We consider RLT forms both with and without these inequalities, and their comparisons with linearizations derived from published methods. Interestingly, the computational results depend in part upon the commercial software used. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

Fully sequential procedures for comparing constrained systems via simulation

We consider the problem of finding the system with the best primary performance measure among a finite number of simulated systems in the presence of a stochastic constraint on a single real‐valued secondary performance measure. Solving this problem requires the identification and removal from consideration of infeasible systems (Phase I) and of systems whose primary performance measure is dominated by that of other feasible systems (Phase II). We use indifference zones in both phases and consider two approaches, namely, carrying out Phases I and II sequentially and carrying out Phases I and II simultaneously, and we provide specific example procedures of each type. We present theoretical results guaranteeing that our approaches (general and specific, sequential and simultaneous) yield the best system with at least a prespecified probability, and we provide a portion of an extensive numerical study aimed at evaluating and comparing the performance of our approaches. The experimental results show that both new procedures are useful for constrained ranking and selection, with neither procedure showing uniform superiority over the other.© 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

浅析汉语应用中的问题及对策

在英语等强势语言的影响下,受到网络语言等非主流语言的冲击,汉语应用中出现了一些问题。分析现阶段汉语应用现状,找出汉语污染源,有利于有的放矢地加强汉语保护工作。     

兵团少数民族教师双语培训中存在的问题与对策

兵团中小学少数民族教师双语培训工程自2005年实施以来,已进行五期学员培训,在取得成绩获得经验的同时,也出现了不少值得思考的问题。本文从兵团少数民族教师双语培训的教学管理,日常管理,教育实习,学员自身等几个方面进行详细分析,针对主要问题及其成因进行客观深入地分析并提出相应的对策,在全面推行少数民族双语教育的今天,具有非常重要的现实意义。     

二次型极小化问题的迭代算法

在新的控制条件下,证明了二次型极小化问题的迭代算法的有效性,所得结果改进了徐洪坤关于二次型优化的最新结果。     

Analysis of a machine repair problem with an unreliable server and phase type repairs and services

In this paper we study a machine repair problem in which a single unreliable server maintains N identical machines. The breakdown times of the machines are assumed to follow an exponential distribution. The server is subject to failure and the failure times are exponentially distributed. The repair times of the machine and the service times of the repairman are assumed to be of phase type. Using matrix‐analytic methods, we perform steady state analysis of this model. The time spent by a failed machine in service and the total time in the repair facility are shown to be of phase type. Several performance measures are evaluated. An optimization problem to determine the number of machines to be assigned to the server that will maximize the expected total profit per unit time is discussed. An illustrative numerical example is presented. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 462–480, 2003     

A bidirectional heuristic for maximizing the net present value of large‐scale projects subject to limited resources

We consider the scheduling of large‐scale projects to maximize the project net present value given temporal and resource constraints. The net present value objective emphasizes the financial aspects of project management. Temporal constraints between the start times of activities make it possible to handle practical problem assumptions. Scarce resources are an expression of rising cost. Since optimization techniques are not expedient to solve such problems and most heuristic methods known from literature cannot deal with general temporal constraints, we propose a new bidirectional priority‐rule based method. Scheduling activities with positive cash flows as early and activities with negative cash flows as late as possible results in a method which is completed by unscheduling techniques to cope with scarce resources. In a computational experiment, we compare the well‐known serial generation scheme where all activities are scheduled as early as possible with the proposed bidirectional approach. On the basis of a comprehensive data set known from literature containing instances with up to 1002 activities, the efficiency of the new approach is demonstrated. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2003