JXTA网络短链路由改进算法

JXTA为构建对等网络提供了标准化计算平台,制定一些协议和服务专门解决构建P2P网络所遇见的问题.为了改进JXTA路由查询效率低下问题,提出一种路由短链改进算法.在端点路由协议的基础上,根据小世界短链现象采用物理邻居策略将网络划分簇,簇内采用Pastry算法,簇间运用freePastry算法进行资源搜索,使长跳路由减少短链路由增加.通过仿真实验说明,算法可有效增加检索效率,减少节点间的通讯时延.     

Benders decomposition with alternative multiple cuts for a multi‐product closed‐loop supply chain network design model

In this article, we consider a multi‐product closed‐loop supply chain network design problem where we locate collection centers and remanufacturing facilities while coordinating the forward and reverse flows in the network so as to minimize the processing, transportation, and fixed location costs. The problem of interest is motivated by the practice of an original equipment manufacturer in the automotive industry that provides service parts for vehicle maintenance and repair. We provide an effective problem formulation that is amenable to efficient Benders reformulation and an exact solution approach. More specifically, we develop an efficient dual solution approach to generate strong Benders cuts, and, in addition to the classical single Benders cut approach, we propose three different approaches for adding multiple Benders cuts. These cuts are obtained via dual problem disaggregation based either on the forward and reverse flows, or the products, or both. We present computational results which illustrate the superior performance of the proposed solution methodology with multiple Benders cuts in comparison to the branch‐and‐cut approach as well as the traditional Benders decomposition approach with a single cut. In particular, we observe that the use of multiple Benders cuts generates stronger lower bounds and promotes faster convergence to optimality. We also observe that if the model parameters are such that the different costs are not balanced, but, rather, are biased towards one of the major cost categories (processing, transportation or fixed location costs), the time required to obtain the optimal solution decreases considerably when using the proposed solution methodology as well as the branch‐and‐cut approach. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

Should firms conceal information when dealing with common suppliers?

A firm making quantity decision under uncertainty loses profit if its private information is leaked to competitors. Outsourcing increases this risk as a third party supplier may leak information for its own benefit. The firm may choose to conceal information from the competitors by entering in a confidentiality agreement with the supplier. This, however, diminishes the firm's ability to dampen competition by signaling a higher quantity commitment. We examine this trade‐off in a stylized supply chain in which two firms, endowed with private demand information, order sequentially from a common supplier, and engage in differentiated quantity competition. In our model, the supplier can set different wholesale prices for firms, and the second‐mover firm could be better informed. Contrary to what is expected, information concealment is not always beneficial to the first mover. We characterize conditions under which the first mover firm will not prefer concealing information. We show that this depends on the relative informativeness of the second mover and is moderated by competition intensity. We examine the supplier's incentive in participating in information concealment, and develop a contract that enables it for wider set of parameter values. We extend our analysis to examine firms' incentive to improve information. © 2014 Wiley Periodicals, Inc. 62:1–15, 2015     

Generation and storage dispatch in electricity networks with generator disruptions

We present methods for optimizing generation and storage decisions in an electricity network with multiple unreliable generators, each colocated with one energy storage unit (e.g., battery), and multiple loads under power flow constraints. Our model chooses the amount of energy produced by each generator and the amount of energy stored in each battery in every time period in order to minimize power generation and storage costs when each generator faces stochastic Markovian supply disruptions. This problem cannot be optimized easily using stochastic programming and/or dynamic programming approaches. Therefore, in this study, we present several heuristic methods to find an approximate optimal solution for this system. Each heuristic involves decomposing the network into several single‐generator, single‐battery, multiload systems and solving them optimally using dynamic programming, then obtaining a solution for the original problem by recombining. We discuss the computational performance of the proposed heuristics as well as insights gained from the models. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 493–511, 2015     

装备项目型供应链风险控制策略

项目型供应链管理模式能有效实现装备研制过程中行为主体间的优势互补和资源的优化配置,利于供应链整体效益的提高,但各种不确定性因素会导致主体间风险传递行为的发生。为提供风险控制有效对策,通过考虑节点位置重要度和属性重要度,构建了项目型供应链节点重要度评估模型;通过衡量行为主体风险识别和风险控制的努力程度,给出了行为主体抗风险努力程度的评价方法,最后提出了一种基于节点重要度和抗风险努力程度的项目型供应链利益分配策略,该策略能有效促使行为主体主动进行风险识别和风险控制,是一种"风险共担、利益共享"的项目型供应链合作博弈策略。     

关于推进农业产业化经营的思考

推进农业产业化经营的关键是抓务实。这就要求:从科学区分外部拉动型、内部合作型、产业链一体化型三种农业产业化经营基本类型和正确处理土地规模经营与家庭承包经营、发展农业与发展其他产业、政府宏观调控与企业、农户自主经营的关系入手,科学选择农业产业化经营的模式;在正确把握目前我国农业产业化经营在农产品竞争力、市场建设、利益机制、政府行为等方面存在的问题的基础上,采取相应对策。     

Lot streaming with supplier–manufacturer coordination

Lot splitting refers to breaking a production lot into smaller sublots during production. Coordinating lot splitting decisions across multiple stages of a production process is a challenging task. Traditional lot splitting and lot streaming models implicitly assume that the entire system is operated and owned by the same firm, or there exists a coordinator who controls the operation of all machines in the system. In this paper, we consider the situation where the machines in a multiple‐stage production process are owned and managed by different companies. Every item in a given production lot has to go through the processing by the supplier's machine, followed by the manufacturer's machine, and so on. We develop and analyze coordination mechanisms that enable different parties in the supply chain to coordinate their lot splitting decisions so as to achieve a systemwide optimum. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

基于干扰管理思想的应急装备器材供应扰动恢复模型

为解决应急条件下装备器材供应过程中由于运力受扰而产生的干扰问题,基于干扰管理思想,提出了应急装备器材供应扰动恢复问题的转化策略,构建了基于虚拟需求点的运力受扰扰动恢复模型;为寻求最优解,设计了基于遗传算法的人工鱼群优化算法。通过算例对模型和算法的有效性进行了验证。     

二级库存-运输系统的联合经济订购模型

结合器材供应的实际,构建了一个国家仓库-地区仓库形成的二级库存-运输系统,以最低费用为目标,建立了该系统的联合经济订购模型,求解了该系统各仓库的最佳订货量和订货次数;运用该模型对3种订货策略（年度1次订货、年度多次订货、零库存订货）进行了算例验证,表明了该模型在优化多级库存运输系统订货参数方面的意义。     

Double Mover–Stayer model on customer switching in telecommunications industry

Customer acquisition and customer retention are the most important challenges in the increasingly competitive telecommunications industry. Traditional studies of customer switching always assume that customers are homogeneous, and thus that model customer switching behavior follows a Markov formulation. However, this postulation is obviously inappropriate in most instances. Blumen et al. (Cornell Studies of Industrial and Labor Relations, Cornell University Press, Ithaca, NY, 1955) developed the Mover–Stayer (MS) model, a generalization of the Markov chain model, to relax the requirement of homogeneity and allow the presence of heterogeneity with two different types of individuals—“stayers,” who purchase the same kinds of products or services throughout the entire observation period; and “movers,” who look for variety in products or services over time. There are two purpose of this article. First, we extend the MS model to a Double Mover‐Stayer (DMS) model by assuming the existence of three types of individuals in the market: (1) stable and loyal customers, who have stable usage within the same company; (2) instable but loyal customers, whose usage varies within the same company over time; and (3) disloyal customers, who switch from one company to another to seek for new experiences or/and benefits. We also propose an estimation method for the DMS model. Second, we apply the DMS model to telecommunications data and demonstrate how it can be used for pattern identification, hidden knowledge discovery, and decision making. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012