Lower Bound Restrictions on Intensities in Data Envelopment Analysis

We propose an extension to the basic DEA models that guarantees that if an intensity is positive then it must be at least as large as a pre-defined lower bound. This requirement adds an integer programming constraint known within Operations Research as a Fixed-Charge (FC) type of constraint. Accordingly, we term the new model DEA_FC. The proposed model lies between the DEA models that allow units to be scaled arbitrarily low, and the Free Disposal Hull model that allows no scaling. We analyze 18 datasets from the literature to demonstrate that sufficiently low intensities—those for which the scaled Decision-Making Unit (DMU) has inputs and outputs that lie below the minimum values observed—are pervasive, and that the new model ensures fairer comparisons without sacrificing the required discriminating power. We explain why the low-intensity phenomenon exists. In sharp contrast to standard DEA models we demonstrate via examples that an inefficient DMU may play a pivotal role in determining the technology. We also propose a goal programming model that determines how deviations from the lower bounds affect efficiency, which we term the trade-off between the deviation gap and the efficiency gap.     

Optimising a Probabilistic Model of the Development of Play in Soccer

We present a probabilistic model based on the one developed by Hernández Mendo and Anguera (Revista de Psicologíca Social, 16(1), 71–93, 2001). Here we have tried to break down the interaction contexts that the opposing teams are able to generate and transform during the game. We are aware that a given player or team does not produce consistent behaviour in similar situations. However, a degree of uncertainty is assumed to exist regarding whether the results obtained are a specific function of the analysis used. In order to carry out this research a category system which optimized that used in the previous model was developed. This system should enable the interaction between teams to be observed within the actual play of a soccer game. A lag sequential analysis was performed on the basis of a coding of the behavioural flow. After describing the behavioural patterns obtained a probabilistic model of the development of play in soccer is proposed.     

基于顾客导向的物流企业风险预警

文中通过回顾企业风险预警管理相关文献,分析了物流企业风险形成主要影响因素,并结合物流企业运营特征,建立基于顾客导向的物流企业预警指标体系,运用灰关联分析方法评价物流企业顾客满意度,对物流企业的风险进行预警。     

Preventing HIV in injection drug users: exploring the tradeoffs between interventions

Injection drug users (IDUs) transmit the human immunodeficiency virus (HIV) via both needle sharing and sex. Available interventions for this population have varying costs and effectiveness and focus on different risk behaviors. In this analysis, we look at two interventions. One is inexpensive, broad-based and provides modest risk reductions (street outreach (SO)); the other is narrowly focused, expensive and relatively effective (methadone maintenance). This analysis explores the effects of population risk behavior, intervention effectiveness, intervention costs, and decision constraints when allocating funds between these two interventions to maximize effectiveness. We develop a model of the spread of HIV, dividing IDUs into susceptibles (uninfected) and infectives, and separately portraying sex and injection risk. We simulate the epidemic in New York City for time periods from the mid-1980s to the early 1990s, and incorporate the behavioral effects of two interventions performed singly or in combination to find the allocation that maximizes the number of infections averted in the IDUs and their noninjecting sex partners, assuming interventions have increasing marginal costs. We find that the optimal allocation nearly always involves spending the maximum allowable amount on SO. This result is largely insensitive to variations in risk parameters, intervention efficacy, or cost. The model's structure, however, makes clear that many factors contribute to this insensitivity, namely the scope of the interventions, the dual drug/sex nature of HIV risk in the population, the asymmetry of sexual risk for men and women, and the potential benefits to nonIDUs.     

Selecting Sites for New Facilities Using Data Envelopment Analysis

This paper develops a mathematical programming model for obtaining a best set of sites for planned facilities. The model is concerned with those situations where resource constraints are present. The specific setting for the paper involves the selection of sites for a set of retail outlets, wherein the ratio of aggregate outputs to inputs for the selected set is maximal among all possible sets that could be chosen. At the same time, the model guarantees that the only sets of stores allowable are those for which the available resources are used to the maximum extent possible.     

湿地公路与农田水利建设关系分析

湿地因其特殊的自然状况，公路交通建设投资大，成绩显著，但农田水利设施损失严重，正确处理好湿地公路建设与农田水利建设的矛盾，有利于发展交通建设和解决三农问题。文章从公路交通与农田水利现状分析出发，试图找到湿地交通发展与农田水利建设的平衡点，形成公路建设，农田水利建设共同发展的良好循环。     

Hybrid governance and governance performance in industrial purchasing relationships

Hybrid governance arrangements (e.g. joint action, long-term contracting and vertical coordination) feature regularly as an effective response to inter-firm dependence in the literature of business-to-business relationships. However, current empirical work has paid little attention to whether such governance arrangements really do improve governance efficacy and reduce transaction costs. The present study focuses on the governance efficacy of vertical coordination in industrial business-to-business relationships. Building on transaction costs arguments, the author examines whether vertical coordination is an effective means for adapting to inter-firm dependence, realized as the substantial employment of specific assets.Empirical findings from a survey of 170 industrial supplier–buyer relationships demonstrate that when asset specificity reaches a certain level, greater vertical coordination reduces ex post transaction costs significantly. On the other hand, this efficacy pattern is modest or non-existent in relationships with low asset specificity.The research findings support the basic TCA assumption that the performance of hybrid governance arrangements is highly dependent on a situation of substantial inter-firm dependence with subsequent small-number conditions.     

基于主成份分析的江苏省各市区经济发展潜力评价

本文选取15项适当的主要经济指标构建了评价指标体系,基于主成分分析法和SPSS12.0数据处理,对江苏省13个市(区)进行了定量分析。根据各地区的综合得分以及排名评价了江苏各市区的经济发展水平同时指出了各地区社会经济发展不平衡的原因,提出相应的对策,为挖掘江苏社会经济发展的潜力提供了一定的借鉴作用。     

不同企业下物流信息系统的实现

本文首先讨论了不同企业建立物流信息系统的前提要求，然后指出了不同企业下构建物流信息系统的基本原则和模式，并提出了在国内的特殊环境下企业构建物流信息系统的几点建议。     

On the Use of Value Efficiency Analysis and Some Further Developments

The purpose of this paper is to discuss the use of Value Efficiency Analysis (VEA) in efficiency evaluation when preference information is taken into account. Value efficiency analysis is an approach, which applies the ideas developed for Multiple Objective Linear Programming (MOLP) to Data Envelopment Analysis (DEA). Preference information is given through the desirable structure of input- and output-values. The same values can be used for all units under evaluation or the values can be specific for each unit. A decision-maker can specify the input- and output-values subjectively without any support or (s)he can use a multiple criteria support system to assist him/her to find those values on the efficient frontier. The underlying assumption is that the most preferred values maximize the decision-maker's implicitly known value function in a production possibility set or a subset. The purpose of value efficiency analysis is to estimate a need to increase outputs and/or decrease inputs for reaching the indifference contour of the value function at the optimum. In this paper, we briefly review the main ideas in value efficiency analysis and discuss practical aspects related to the use of value efficiency analysis. We also consider some extensions.