软件限时开发方法的研究与应用

限时开发是快速应用开发的最佳实践之一。文章介绍了限时开发的基本概念和优点以及适用的项目范围,通过一个进销存软件的开发实例说明如何成功地应用限时开发方法。     

逆向物流再造网络成本优化的相关机会目标规划模型研究

逆向物流凭借着其重大的经济社会价值，成为了企业物流战略的重要组成部分。本文简要介绍了逆向物流的经济价值和特点，划分了逆向物流产品构成，重点研究了逆向物流再造网络的结构和特点，并运用相关机会规划理论建立了逆向物流再造网络的成本优化模型。     

基于粒子群优化的模糊聚类分析

基于求解实优化问题时,粒子群优化算法优于遗传算法。在基于遗传算法的模糊C均值聚类算法基础上,给出了基于粒子群的模糊C均值聚类算法,试验结果表明:该算法克服了传统的模糊C均值聚类算法的缺陷,同时在收敛速度方面明显优于基于遗传算法的模糊C均值聚类算法。     

基于时间约束的多源多品种随机配送系统模型

在基于时间竞争的随机需求环境下,配送系统设计除了使系统总费用的期望值最小外,还要考虑系统稳定性和服务水平等方面的要求。在说明了建模的假设条件后,建立了考虑随机需求和时间约束的多源配送系统随机模型。通过等价变换,将随机模型转化为确定性等价问题,从而方便了问题的求解。     

Theory and practice of monetary policy

Summary. We consider an optimally managed renewable resource with stochastic non-concave growth function. We characterize the conditions under which the optimal policy leads to global extinction, global conservation and the existence of a safe standard of conservation. Our conditions are specified in terms of the economic and ecological primitives of the model: the biological growth function, the welfare function, the distribution of shocks and the discount rate. Our results indicate that, unlike deterministic models, extinction and conservation in stochastic models are not determined by a simple comparison of the growth rate and the discount rate; the welfare function plays an important role.Received: 20 October 2004, Revised: 28 February 2005, JEL Classification Numbers: D90, O11, O41, Q32.Santanu Roy: Correspondence toResearch on this paper was completed when the second author visited Cornell University in July, 2003. We thank the Center for Analytic Economics and the Department of Economics at Cornell University for making this research visit possible. The current version has gained considerably from the comments made by an anonymous referee.     

基于网络规划的道路系统设计

针对物流系统设计，基于网络规划法提出了一种在物流中心已经确定的条件下，进行道路系统的新的设计方法。通过合理但设把道路系统的设计转变为网络规划中求解最短路径的问题．通过统计每个路段的最短路径通过率．得出路段的运量负担情况，从而为道路的功能和等级设计提供依据。在此基础上．以宁波化工区的物流系统为例，建立了宁波化工区道路系统的网络模型，对宁波化工区的道路系统进行了功能设计。结果表明，该方法在区域物流系统设计中有良好的应用前景．     

既有结构可靠度的模糊算法

基于结构抗力和荷载效应的不确定性，提出了一种既有结构工程可靠度的模糊算法。该方法利用模糊算法可以反映客观事物因素的层次性，又便于比较和考虑各层次中诸因素作用的大小以决定可靠度。算例结果表明该方法简单实用，其模型可以很好地拟合真实的极限状态函数，是解决既有结构体系可靠度问题的有效方法。     

独立审计质量的经济学分析

本文通过对审计质量的经济学分析,提出高质量的审计是增进契约效率的内生需要,中小股东和上市公司之间的“隐性契约”是推动审计质量提高的重要力量。我国特有的经济环境背景,决定了审计质量的提高存在着制度性障碍,审计质量是各方利益相互均衡的结果。     

Uncertain Climate Change in an Intergenerational Planning Model

A three-generation planning model incorporating uncertain climate change is developed. Each generation features a production activity based on capital and an exhaustible resource. An irreversible climate change may occur in period two or three, reducing the productivity for this and the remaining generation. The model is solved by stochastic dynamic programming. If the climate impact and climate change probability is constant, the optimal period one (and two) resource extraction is larger than for the reference case of climate stability. If, however, climate impact and climate change probability increases with increased aggregate resource use, this result is reversed.     

Portfolio Optimization under Lower Partial Risk Measures

Portfolio management using lower partial risk (downside risk) measures is attracting more attention of practitioners in recent years. The purpose of this paper is to review important characteristics of these riskmeasures and conduct simulation using four alternative measures, lower semi-variance, lower semi-absolute deviation, first order below targetrisk and conditional value-at-risk.We will show that these risk measures are useful to control downside risk whenthe distribution of assets is non-symmetric. Further, we will propose a computational scheme to resolve the difficultyassociated with solving a large dense linear programming problems resulting from these models. We will demonstrate that this method can in fact solve problems consisting of10⁴ assets and 10⁵ scenarios within a practical amount of CPU time.