Effects of an animal disease shock on meat markets and producer income

This paper simulates pig producer and slaughterhouse income losses due to a classical swine fever outbreak in Finland. The analysis explicitly takes into account that an outbreak of a highly contagious animal disease can shrink export demand for pig meat. After having observed the disease and its impact on pig meat price, producers can optimize animal stocks thought insemination decisions, which affects the number of animals in a dynamic manner. The income losses of pig industry were estimated to be less than €30 million. The losses were mainly due to price movements caused by an export demand shock. The results suggest that if the outbreak causes distortions in meat trade, the disease can cause substantial losses to the industry even if it has directly a small impact on the number of animals on farms. We also found that the optimization could reduce disease losses significantly, even more than 50%.     

PLC输入I/O点数的扩展方法

介绍了 PL C输入 I/ O点数的硬件软件扩展方法 ,为在实际应用中解决 PL C输入点数不足 ,降低系统的硬件费用 ,提出了很好的解决方法     

Discounting long run average growth in stochastic dynamic programs

Summary. Finding solutions to the Bellman equation often relies on restrictive boundedness assumptions. In this paper we develop a method of proof that allows to dispense with the assumption that returns are bounded from above. In applications our assumptions only imply that long run average (expected) growth is sufficiently discounted, in sharp contrast with classical assumptions either absolutely bounding growth or bounding each period (instead of long run) maximum (instead of average) growth. We discuss our work in relation to the literature and provide several examples. Received: July 26, 2000; revised version: July 10, 2002 RID="*" ID="*" I am specially grateful to Cuong Le Van and to anonymous referee for detecting an error in a previous version of this paper and for suggestions that sensibly improved the paper. Comments and suggestions are also acknowledged to Michele Boldrin, Raouf Boucekkine, Fabrice Collard, Tim Kehoe, Omar Licandro, and Luis Puch. I am also indebted to participants to the III Summer School on Economic Theory held at the Universidade de Vigo, the Macroeconomics Workshop at the Universitat Autò}noma de Barcelona, and the Econometrics Seminar at Tilburg University. Financial support from the Belgian government, under project PAI P4/01, at the IRES-UCL, from a European Marie Curie fellowship, Grant HPMF-CT-1999-00410, at the CEPREMAP, and from IVIE and Spanish Ministerio de Ciencia y Tecnología and FEDER, under project BEC2001-0535, at the Universidad de Alicante, is gratefully acknowledged.     

Programming for the Internet and Experiential Learning: a New Approach Incorporating a Constructed World

This paper reports on a novel approach taken by the author to the teaching of an Internet programming course targeted at final year diploma and second year degree students. The uniqueness of engineers and their identity is discussed, as is the self-constructed world and ways of knowing in which humankind operates. The novel approach to teaching a software-coding course, and this course’s underlying philosophies of learning, the approach taken in class-contact time, and the methods of interaction with the students are presented, along with the conventional structure, quantitative measures, outline, and assessment of the course. The effects and observations of approaches employed are discussed, and the quantitative outputs achieved are presented alongside the unquantifiable impressions, comments and positive feedback.     

Economies of Product Diversity in Collaborative Logistics

Collaborative logistics, also known as shipper collaboration, is a method of reducing the freight logistics cost of firms that produce and/or distribute tangible goods (shippers), which seeks to improve capacity utilizations of trucks. This study looks at this shipper collaboration problem in the U.S. truckload (TL) industry and proposes a new approach. Unlike other studies, which focused on reducing TL costs by utilizing economies of density, we present an approach that utilizes specific TL economies gained by mixing multiple products with different weight‐to‐volume ratios, which we call economies of product diversity. Using theoretical and empirical evidence, we show that the performance of shipper collaboration can be enhanced notably using this concept, economies of product diversity, which is currently overlooked in the literature.     

项目教学法在VB程序设计课程中的应用研究

项目教学法是一种以项目内容为中心的新型教学模式,它通过选取项目创设学习情景,以协作学习的方式开展学习,实现项目的完成。项目教学法在VB程序设计课程教学中的成功应用,体现了以学生为主体,强化技能教学,充分发挥学生创新精神的教学思想。     

A DC programming heuristic applied to the logistics network design problem

This paper proposes a new heuristic method for the logistics network design and planning problem based on linear relaxation and DC (difference of convex functions) programming. We consider a multi-period, multi-echelon, multi-commodity and multi-product problem defined as a large scale mixed integer linear programming (MILP) model. The method is experimented on data sets of various size. The numerical results validate the efficiency of the heuristic for instances with up to several dozens facilities, 18 products and 270 retailers.     

An input-and output-oriented data envelopment analysis model

Considering the conventional data envelopment analysis （DEA） model used to measure the relative efficiencies of a group of decision making units （DMUs） is limited to either input or output orientation, a new DEA model which is both input-and output-oriented is proposed in this paper. This model can be treated as a multi-objective programming problem and solved by fuzzy sets theory. The basic idea is to describe the efficient frontier with fuzzy observation and determine projections for DMUs on the frontier by using the fuzzy optimization approach. The measurement of efficiencies for DMUs is obtained by comparing the inputs and outputs of DMUs with their projections. Since the input- and output-oriented DEA model can be transformed into a conventional input- or output-oriented DEA model by using special membership functions, it is therefore more adaptive for efficiency measurement. Finally, a typical example is presented to illustrate the computation methods.     

Goal programming: Planning process of tourism organizations

The complex rapidly changing environment faced by tourism organization officials makes tourism planning extremely difficult. Goal programming can aid the tourism planner in appraising the goal attainment potential associated with proposed tourism marketing program alternatives. By changing priorities of goals, budgetary limitations, and organizational constraints, the policy maker can test the effect of changes before they are implemented. By utilizing goal programming, a tourism organization can more systematically evaluate the nature and relative importance of organizational goals, critical constraints affecting the organization and marketing program alternatives.