Searching for multiobjective preventive maintenance schedules: Combining preferences with evolutionary algorithms

Heavy industry maintenance facilities at aircraft service centers or railroad yards must contend with scheduling preventive maintenance tasks to ensure critical equipment remains available. The workforce that performs these tasks are often high-paid, which means the task scheduling should minimize worker idle time. Idle time can always be minimized by reducing the workforce. However, all preventive maintenance tasks should be completed as quickly as possible to make equipment available. This means the completion time should be also minimized. Unfortunately, a small workforce cannot complete many maintenance tasks per hour. Hence, there is a tradeoff: should the workforce be small to reduce idle time or should it be large so more maintenance can be performed each hour? A cost effective schedule should strike some balance between a minimum schedule and a minimum size workforce.     

Rethinking Statistics Teaching for Operational Research

Statistics is a standard component of most Management Science or Operational Research courses. This paper argues that the teaching of Statistics in such courses should emphasise the philosophical aspects of the discipline, should concentrate on developing concepts rather than techniques, should stimulate ideas and should allow each student to reach his/her own level in the discipline. A postgraduate course structured in this way is described in detail.     

非对称信息条件下的企业人力资源规划研究

本论针对企业管理中存在的员工工作表现难考核和信息不对称的问题，提出企业首先要根据各类职务的工作性质制定出可量化的标准(合理)的工作绩效水平，其次在信息不对称的情况下，考虑管理成本的节约，建立博弈模型，最后得出企业应选取的最优监督概率和员工的违规概率，据此采取相应的策略以取得最好的经济效益。     

Stock Levels for Slow-Moving Items

When setting stock levels for slow-moving items, a decision should be taken as to whether the item should be stocked at all. Formulae are developed for making this decision, and for determining the optimum stock if the item should be carried.     

On the optimization of supply chain networking decisions

Companies strive to position themselves to maximize the value they add to the supply chains in which they are embedded. This raises strategic questions such as: Which durable resources should be developed to enhance current core competencies? Which activities should be externalized and to which potential partner should they be given? Which internal activities should be preserved and developed? How should the resources of the enterprise be allocated to activities? The aim of this paper is to propose a mathematical programming model of the extended enterprise which can be used to investigate this type of strategic networking issues. A number of general network modeling constructs are first proposed. A model to optimize the supply chain structure under specific assumptions on the nature of production, cost and value functions in typical production/distribution companies is then derived. A heuristic to obtain solutions from the model is also presented. Finally, an example based on a refrigerator company is used to illustrate the usefulness of the approach.     

社会演进中钢未来使用规律预测及政策分析

运用国际上新兴的动态物质流分析方法,对2014~2100年中国钢使用规律进行预测。研究发现,2014年至21世纪30年代,中国人均钢存量迅速增长,并于2035年以后达到饱和。在联合国中等方差人口增长情景下,2014年以后中国钢总存量出现了先迅速上升、后逐步下降的态势。中国未来钢消费量将于2015年左右达到峰值。2035年以后,钢退役量将超过钢消费量,并于消费峰值出现的30年后达到最大值。根据上述钢未来使用规律,中国应根据消费峰值出现的时间和数量合理安排钢的生产量,并于消费峰值出现之前做好减产准备;提高退役钢的处理能力,加强循环技术研究,实现资源解耦;开拓国际钢铁市场,与初级工业化国家进行产业联合,释放过剩产能。     

Predicting the future of scholarly publishing

Conclusions  What should we conclude? Should we steadfastly maintain the status quo? Do we avoid technology altogether? Of course not.We should experiment; we should try out new things; we should tinker with technology and find better ways to communicate. This article is based on a talk given at the Conference on Electronic Information and Communication, Tsinghua University, China, August 29-31, 2002. A version of this paper will appear in the proceedings of that conference.     

关于极限理论的学习经验

分析极限理论在数学分析学习中的重要性，介绍学习极限理论的三点经验与体会，即充分理解基本内容；加强基本功训练；试着多问自己一些问题，学会举出各种各样的例子。     

Mechanisms and Difference-Making

I argue that difference-making should be a crucial element for evaluating the quality of evidence for mechanisms, especially with respect to the robustness of mechanisms, and that it should take central stage when it comes to the general role played by mechanisms in establishing causal claims in medicine. The difference-making of mechanisms should provide additional compelling reasons to accept the gist of Russo-Williamson thesis and include mechanisms in the protocols for Evidence-Based Medicine (EBM), as the EBM+ research group has been advocating.     

A dynamic analysis of corporate investments and emission tax policy in an oligopoly market with network externality

We investigate the product innovation, green R&D investments and the emission tax policy in an oligopoly market with network externality. It is shown that an appropriate tax policy should be deployed to effectively control pollution and motivate innovation. At the early stage of the market, the emission tax should gradually reduce to motivate firms to achieve optimal investments. Later at the mature stage, the emission tax policy should carefully consider both the market competition and green technology levels.     

Japanese and American teachers' evaluations of mathematics lessons: A new technique for exploring beliefs

In our study, we use a novel technique to explore the beliefs of Japanese and American elementary school teachers. Four American and four Japanese teachers watched a mathematics lesson—videotaped in either Nagano, Japan or Chicago, Illinois—and commented on the lesson's strengths and weaknesses. The major pedagogical issues that differentiated the teachers' comments were: what students should do during a lesson, how instructors should use language, how instructors should pace lessons and address ability differences, and how instructional materials should be used. The specific beliefs of the American and Japanese teachers in this study mapped easily onto common instructional practices in elementary school mathematics classes in the United States and Japan. We conclude that, at least for the teachers in this sample, beliefs are linked to practices and they may help to tie teachers to their culturally preferred method of mathematics instruction.     

A stochastic approach to professional services firms’ revenue optimization

Regarding professional service time as perishable goods, it should be possible to directly migrate the successful airline revenue management techniques to professional services firms (PSFs) for their analogous business characters. However, there are salient differences between airlines and PSFs should be highlighted—the network structure of length-of-continuance and capacity allocation of multifunctional staff. Customers booking to be served from a first continuance time to a last continuance time in consecutive time continuance. Multifunctional professionals should be properly allocated to maximize the benefit. The arrival demands and lengths of service are stochastic in nature.     

Stability of the Cournot process – experimental evidence

We report results of experiments designed to test the predictions of the best-reply process. In a Cournot oligopoly with four firms, the best-reply process should theoretically explode if demand and cost functions are linear. We find, however, no experimental evidence of such instability. Moreover, we find no differences between a market which theoretically should not converge to Nash equilibrium and one which should converge because of inertia. We investigate the power of several learning dynamics to explain this unpredicted stability. Received May 1997/Revised June 2002     

开源软件服务提供商的市场策略及社区参与策略研究

开源软件由开源社区内的成员自发参与并协同完成开发,是一种高效的、有别于传统的软件生产模式。开源社区的主要成员有软件用户及开源软件服务提供商。本文通过构建三阶段模型,研究了服务提供商的市场策略及开源社区内用户创新对服务提供商参与策略的影响。研究发现:(1)若市场上高价值用户较少,服务提供商应采取低质量、低价格的市场策略,否则应采取高质量、高价格策略。(2)服务提供商要避免搭便车行为,即为了增加服务利润,它必须投入资源参与开源社区、提高软件质量。(3)当服务市场上目标用户较多且开源社区内用户参与动机较强时,服务提供商应采取高参与策略,否则采取低参与策略。本文的研究对服务提供商如何利用和参与开源社区具有指导意义。     

Mathematics: a means of collaboration between industry and university

This paper is divided into two distinct but connected parts. In the first one we look for the best approach to the Mathematics teaching of the future engineer. This approach should have an eminently pragmatic character and should be directed towards teaching engineers to know and manage Mathematics at a tool. In the second part we illustrate how a collaboration with industry can be obtained from this kind of teaching.

Finally the conditions and consequences which should produce this cooperation are analysed, and some particular examples are mentioned.