A quadratic time exact algorithm for continuous connected 2-facility location problem in trees

This paper studies the continuous connected 2-facility location problem (CC2FLP) in trees. Let \(T = (V, E, c, d, \ell , \mu )\) be an undirected rooted tree, where each node \(v \in V\) has a weight \(d(v) \ge 0\) denoting the demand amount of v as well as a weight \(\ell (v) \ge 0\) denoting the cost of opening a facility at v, and each edge \(e \in E\) has a weight \(c(e) \ge 0\) denoting the cost on e and is associated with a function \(\mu (e,t) \ge 0\) denoting the cost of opening a facility at a point x(e, t) on e where t is a continuous variable on e. Given a subset \(\mathcal {D} \subseteq V\) of clients, and a subset \(\mathcal {F} \subseteq \mathcal {P}(T)\) of continuum points admitting facilities where \(\mathcal {P}(T)\) is the set of all the points on edges of T, when two facilities are installed at a pair of continuum points \(x_1\) and \(x_2\) in \(\mathcal {F}\), the total cost involved in CC2FLP includes three parts: the cost of opening two facilities at \(x_1\) and \(x_2\), K times the cost of connecting \(x_1\) and \(x_2\), and the cost of all the clients in \(\mathcal {D}\) connecting to some facility. The objective is to open two facilities at a pair of continuum points in \(\mathcal {F}\) to minimize the total cost, for a given input parameter \(K \ge 1\). This paper focuses on the case of \(\mathcal {D} = V\) and \(\mathcal {F} = \mathcal {P}(T)\). We first study the discrete version of CC2FLP, named the discrete connected 2-facility location problem (DC2FLP), where two facilities are restricted to the nodes of T, and devise a quadratic time edge-splitting algorithm for DC2FLP. Furthermore, we prove that CC2FLP is almost equivalent to DC2FLP in trees, and develop a quadratic time exact algorithm based on the edge-splitting algorithm. Finally, we adapt our algorithms to the general case of \(\mathcal {D} \subseteq V\) and \(\mathcal {F} \subseteq \mathcal {P}(T)\).     

可变产能的按订单装配系统库存和生产决策研究

本文基于一个ATO 生产商的实践,考虑一个需求不确定并具有子装配件的单周期ATO 系统,为了应对较长的采购提前期和有限产能的挑战,生产商可以在得到确定的需求之前提前采购零件,装配子装配件以至于最终产品。由于产品物料清单结构中存在子装配件作为可选的中间件,因此完全使用零件和使用子装配件装配最终产品的不同,造成装配能力在时间上具有可变性。我们对此问题建立了利润最大化模型,分析在上述ATO 环境中的最优库存和生产决策。通过一系列最优解的性质,我们得到了该问题的有效解决方法。     

股市波动率的短期预测模型和预测精度评价

基于幂转换以及不设定扰动项的具体相关结构和分布形式,构建了半参数的短期预测模型来预测中国股市的波动率.模型采用基于极值估计量的两阶段估计法进行估计,估计方法的小样本性质表现良好.此外,还通过具有Bootstrap特性的SPA检验实证比较了新模型与其他6种预测模型的预测精度.实证结果表明,在各种损失函数下,半参数短期预测...     

基于心理契约的劳资博弈模型研究

论文基于心理契约理论,借助于柯布一道格拉斯(Cohb-Dauglass)生产函数,建立了企业劳资双方的博模型,研究发现当单位产品投入资本与单位产品售价之比大于产出的资本弹性时,最优单位产品工资与单位产期望工资成正向变动,与劳方最优有效劳动量成正向变动关系,资方可以通过员工大会等方式降低最优期望单产品工资;反之,情况则相反,资方可以通过加强监管,寻求其他的激励方式提高员工的有效劳动量,从而达到有激励、留住人才的目的.     

网络外部性下的企业R&D竞争与合作行为研究

本文将网络外部性函数引入D'Aspremont C和Jacquemin A(1988)的模型中,研究双寡头企业的R&D活动.每个企业首先确定自己的R&D投入,然后在产品市场上进行竞争.在R&D阶段有合作和竞争两种情况,在每种情况下讨论了网络外部性对企业R&D投入、最优溢出、企业利润和社会福利的影响.研究发现,网络外部性增强会导致企业R&D投入和企业R&D合作利润的增加,且企业的R&D行为有助于改善社会福利.     

上市公司总经理更换、高管团队重组与企业绩效改进

本文针对以往总经理更换理论研究存在的关键问题,特别是对高管团队重组现象的忽视,构建了新的理论假设,并利用中国上市公司数据进行了检验.研究发现,总经理被迫离职时企业绩效呈现改进之面貌,但常规离职时无此效应;国有控股阻碍了企业绩效改进而内部董事则反之,且在总经理被迫离职情况下,前者负效应减弱而后者正效应增强;总经理是否为竞争者继任对企业绩效改进无显著影响,而选择外部继任对其有显著负面效应;总经理更换后的高管团队重组总体上不利于企业绩效改进,但受到继任类型的调节作用,在外部继任情形下消极影响尤为明显,而对竞争者继任则具有积极作用.     

住房保障政策选择的动态分析模型

在中央计划者经济框架内,将无房户率引入效用函数,构建关于公共住房投资和租金补贴的最优增长模型.通过中央计划者的最优决策得到均衡状态,给出均衡状态下的模型最优解和鞍点路径,得出公共住房存量增长对无房户率的影响规律.结论显示,住房保障政策的选择与住宅市场发展阶段、住宅市场供给状况、政府偏好等因素密切相关.这为我国住房保障政策的制定与实施提供了依据.     

虚拟产业群的运作管理模式研究

虚拟产业群是一种松散的企业网络组织,在网络信息技术的支持下成为虚拟企业构建与运作的基础平台。基于这一出发点,本文通过分析与研究虚拟产业群运作的目标、创建过程、组织结构形式、运作过程主要活动及必需的基础设施建设等问题,提出了虚拟产业群运作管理的基本模式。同时,为充分理解这一模式,文后给出了两个实际案例。最后,总结了虚拟产业群运作对虚拟企业的基础作用与价值所在。     

品牌延伸:资产价值转移与理论模型创建

本文通过对品牌延伸(Brand Extension)的研究综述和实证研究,提出决定品牌延伸的三大因子,并在此基础上构成品牌资产价值(Brand Asset Value),进而研究其在品牌延伸过程中的价值转移,从而构成了评估品牌延伸成败的标准,最终将各种因子和评估标准进行整合,提出了品牌延伸的理论模型。     

An Empirical Analysis of Virtual Goods Permission Rights and Pricing Strategies

With the rapid development of the virtual world industry in the past few years, trading of virtual goods and services has grown significantly. Virtual goods creators can set different permissions to their creations, such as the length of usage, the ability to copy or modify a virtual good, or the ability to give the good to others. The permissions of virtual goods endow their creators with additional power to control the allocation and exchange of virtual goods in a virtual world. We examine how the unique virtual goods permission settings (copy, modify, and transfer) and other factors are associated with virtual goods prices. Using data from a Second Life marketplace, we find that permissions of virtual goods are not random, as creators strategically set the permissions for their virtual creations. Our results show that the copy and transfer permissions are significant factors associated with virtual goods prices. The impact of other factors on virtual goods prices is analyzed and managerial implications are discussed.