Capacitated warehouse location model with risk pooling

In this article, we introduce the capacitated warehouse location model with risk pooling (CLMRP), which captures the interdependence between capacity issues and the inventory management at the warehouses. The CLMRP models a logistics system in which a single plant ships one type of product to a set of retailers, each with an uncertain demand. Warehouses serve as the direct intermediary between the plant and the retailers for the shipment of the product and also retain safety stock to provide appropriate service levels to the retailers. The CLMRP minimizes the sum of the fixed facility location, transportation, and inventory carrying costs. The model simultaneously determines warehouse locations, shipment sizes from the plant to the warehouses, the working inventory, and safety stock levels at the warehouses and the assignment of retailers to the warehouses. The costs at each warehouse exhibit initially economies of scale and then an exponential increase due to the capacity limitations. We show that this problem can be formulated as a nonlinear integer program in which the objective function is neither concave nor convex. A Lagrangian relaxation solution algorithm is proposed. The Lagrangian subproblem is also a nonlinear integer program. An efficient algorithm is developed for the linear relaxation of this subproblem. The Lagrangian relaxation algorithm provides near‐optimal solutions with reasonable computational requirements for large problem instances. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

网络舆论战的心理学意义

从舆论战和网络舆论战的概念和特点出发,阐述了心理学在网络舆论战中的重要作用。综合心理学理论和舆论传播理论分析了网络舆论形成的心理机制,得出了网络舆论是通过个体心理和群体心理两个阶段而形成的结论。根据这个结论,提出了网络舆论引导的具体策略。即在个体层面上,通过操纵信息来影响人的认知;在群体层面上,通过塑造引导者主体的可信性和喜爱性,以及网络技术手段来增强舆论引导的效果。最后,指出了网络舆论战的发展前景在于充分考虑受众的心理,有针对性地进行舆论引导。     

The burglar problem with multiple options

We consider the burglar problem in which a burglar can either retire or choose among different types of burglaries, with each type having its own success probability and reward distribution. Some general structural results are established and, in the case of exponentially distributed reward distributions, a solution technique is presented. The burglar problem's relationship to a stochastic knapsack problem with a random exponentially distributed knapsack capacity is shown. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 359–364, 2014     

A branch‐and‐price approach for the stochastic generalized assignment problem

In this article, we address a stochastic generalized assignment machine scheduling problem in which the processing times of jobs are assumed to be random variables. We develop a branch‐and‐price (B&P) approach for solving this problem wherein the pricing problem is separable with respect to each machine, and has the structure of a multidimensional knapsack problem. In addition, we explore two other extensions of this method—one that utilizes a dual‐stabilization technique and another that incorporates an advanced‐start procedure to obtain an initial feasible solution. We compare the performance of these methods with that of the branch‐and‐cut (B&C) method within CPLEX. Our results show that all B&P‐based approaches perform better than the B&C method, with the best performance obtained for the B&P procedure that includes both the extensions aforementioned. We also utilize a Monte Carlo method within the B&P scheme, which affords the use of a small subset of scenarios at a time to estimate the “true” optimal objective function value. Our experimental investigation reveals that this approach readily yields solutions lying within 5% of optimality, while providing more than a 10‐fold savings in CPU times in comparison with the best of the other proposed B&P procedures. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 131–143, 2014     

DEFENSIVE COUNTERTERRORISM MEASURES AND DOMESTIC POLITICS

Unlike most of the literature, this paper includes domestic political considerations in which two countries must decide defensive countermeasures against a common terrorist threat. A delegation problem arises as voters strategically choose a policymaker whose preferences differ from their own. As a consequence, countries limit the presumed oversupply of defensive countermeasures. Thus, the inclusion of domestic politics gives a new perspective on counterterrorism. The timing of elections is also shown to make a difference.     

THE MORAL PERMISSIBILITY OF AUTOMATED RESPONSES DURING CYBERWARFARE

Automated responses are an inevitable aspect of cyberwarfare, but there has not been a systematic treatment of the conditions in which they are morally permissible. We argue that there are three substantial barriers to the moral permissibility of an automated response: the attribution, chain reaction, and projection bias problems. Moreover, these three challenges together provide a set of operational tests that can be used to assess the moral permissibility of a particular automated response in a specific situation. Defensive automated responses will almost always pass all three challenges, while offensive automated responses typically face a substantial positive burden in order to overcome the chain reaction and projection bias challenges. Perhaps the most interesting cases arise in the middle ground between cyber-offense and cyber-defense, such as automated cyber-exploitation responses. In those situations, much depends on the finer details of the response, the context, and the adversary. Importantly, however, the operationalizations of the three challenges provide a clear guide for decision-makers to assess the moral permissibility of automated responses that could potentially be implemented.     

大学英语课堂教学存在的主要问题及应对策略

课堂是学员语言学习实践的重要场所,无论科技怎样发展,教学如何改革,英语课堂教学仍有不可替代的作用。通过调查研究和教学实践发现,武警初级院校的大学英语课堂活力不足,学员学习热情不高。针对这一现象进行原因分析和探究,找到了激活英语课堂气氛的应对策略,便于指导教学实践。     

二次型极小化问题带误差的迭代算法

证明了二次型极小化问题带误差的迭代算法的有效性,所得结果推广了关于二次型极小化问题迭代的收敛性。     

中继卫星调度问题的CSP模型

中继卫星在地球同步静止轨道上运行,既能直视中、低轨道用户航天器,又能直视地面站,是沟通用户航天器与地面站的桥梁。中继卫星调度问题是一类非常重要的调度问题。基于约束满足理论,通过分析中继卫星调度问题的特点与约束条件,建立了中继卫星调度问题的CSP模型。利用卫星工具箱STK进行模拟仿真,对CSP模型进行了求解。结果表明,所建立的CSP模型是合理的。     

一类m-点边值问题的正解

研究一类二阶m-点边值问题u″ f(t,u,u)′=0,00,i=1,…,m-2,ζi满足0=ζ0<ζ1<ζ2<…<ζm-2<ζm-1=1和i∑=1aiζi<1。应用推广的Krasnosel-skii′s不动点定理,给出了上述边值问题至少存在一个正解的充分条件。