An efficient and simple model for multiple criteria supplier selection problem

Simply looking for vendors offering the lowest prices is not “efficient sourcing” any more. Selection of suppliers is a multiple criteria decision. We propose a weighted linear program for the multi-criteria supplier selection problem. In addition to mathematical formulation, this paper studies a transformation technique which enables our proposed model to be solved without an optimizer. The model for multi-criteria supplier selection problem can be easily implemented with a spreadsheet package. The model can be widely applied to practical situations and does not require the user with any optimization background.     

图模型及其在统计建模中的应用

图模型是近年来兴起的一个新的统计研究方向,主要借助拓扑图的直观形式对多维概率分布进行统计推断和因果分析。本文对图模型的基本概念、原理、建模及应用进行了简单介绍。     

Affirmative action algorithms

Affirmative action is a new variety of selection rule which employs historical information to favor the choice of elements that have not been selected in the past. We categorize three implementations of this principle and discuss their application to the simplex method, to Bard-type schemes for the linear complementarity problem, and to augmenting path methods for network flow problems. We present analytical and computational results, and some open questions.Research supported by the Georgia Institute of Technology.Research supported by the New Faculty Research Development Program of the Georgia Institute of Technology. Reproduction in whole or in part is permitted for any purpose of the U.S. Government.     

Supplier switching decisions

In order to maximize profit, a buying firm should continuously search for and access sources which offer more favorable prices. While the literature is replete with works on the formation and development of buyer–supplier relationships, there is surprisingly only scarce research on the termination of such relationships and supplier switching. Using the concept of switching costs in a principal-agent framework, we at first analyze whether a firm switches the entire or a partial quantity to an alternative supplier when there is either symmetric or asymmetric information about the alternative supplier’s cost structure. Information asymmetry results in inert supplier switching decisions. Subsequently, we extend our model and take competitive reactions of the incumbent supplier and economies of scale effects into consideration. We find conditions under which ‘no’, ‘partial’ and ‘complete’ switching occurs, which depend on the buying firm’s beliefs about the alternative supplier’s unit costs, switching costs, the price offered by the incumbent supplier, and refinements of the price offered by the incumbent supplier due to competitive reactions and economies of scale. Broader implications for supplier relationship management and sourcing strategy decisions are also provided.     

Continuous benchmark selections

The existence of benchmark selections that are continuous both in production factors and technology is examined. If the class of technologies display non-convexities, continuous selections do not exist in general. For probabilistic benchmarks, i.e., lotteries over efficient productions, existence of continuous selections holds only under additional conditions of well-behavedness.     

Capacity and entry issues in online exchanges

With the advent of open standards and Internet technologies, the number of sellers who can participate in online exchanges is greatly increased. We model the competition between identical sellers vying for the same business, and find that there exists a mixed-strategy equilibrium in prices. The results help us understand the dynamics between a seller’s capacity and his motivation to participate in an auction.     

Parametric multiple regression risk models: Theory and statistical analysis

Parametric multiple regression models for the claim number and the claim amount of an individual risk are introduced allowing explanatory variables to influence the mean claim number (amount). A model for an entire portfolio of risks is established on this basis. Then an extensive and in many cases efficient statistical analysis of this model is presented.     

On the solution of some (parametric) linear complementarity problems with applications to portfolio selection,structural engineering and actuarial graduation

In this paper we discuss three applications of a class of (parametric) linear complementarity problems arising independently from such diverse areas as portfolio selection, structural engineering and actuarial graduation. After explaining how the complementarity problems emerge in these applications, we perform some analytical comparisons (based on operation counts and storage requirements) of several existing algorithms for solving this class of complementarity problems. We shall also present computational results to support the analytical comparisons. Finally, we deduce some conclusions about the general performance of these algorithms.This research is supported in part by the United States Army under Contract No. DAAG29-75-C-0024, the National Science Foundation under Grant No. MCS75-17385 and Grant ENG77-11136.     

车号识别中的补偿光源

公路交通基础建设的不断发展和车辆管理体制的不断完善,为以视觉监控为基础的智能交通系统的实际应用打下了良好基础。在智能交通系统中,车牌自动识别系统是一个非常重要的发展方向。由于对车辆的监控是全天候的,车牌识别系统必须满足这种工作要求。在监控过程中存在自然光线不足的情况(夜晚,阴雨天等),也就是存在逆光环境中对车牌的识别问题,这样就需要补偿光源。目前大多采用大功率泛光灯作补偿光源。由于泛光灯自身的特点,使效果不能达到理想。文章从汽车车灯的光谱及人眼的光谱光视效率曲线等方面详细分析了逆光条件下车牌识别中补偿光源的选取。并经实验证明此选取方法具有很好的效果。