A note on the projection properties of Hadamard matrices obtained by the first Payley construction

We show that the projections on four factors of an arbitrary orthogonal array of strength 2 allow the estimation of main effects and two-factor interactions when all other effects are assumed to be zero, if those projections satisfy the bounds given by Weils theorem. The only exceptions are the Hadamard matrices of orders 16 and 24. A consequence is again the estimability of main effects and two-factor interactions for the projections on four factors of the first Payley construction for arbitrary run size.     

基于复杂供应链库存管理策略的系统动力学研究

在分析了具有不同提前期和加工时间的复杂供应链特点基础上，研究了混合CONWIP／Kanban库存管理思想与同步CONWIP库存管理思想在复杂供应链上的应用。同时借助Vensim建模平台。针对这两种管理思想建立了基于复杂供应链系统的动态仿真模型，并对模拟结果进行了分析。     

On the evolutionary edge of altruism: a game-theoretic proof of Hamilton’s rule for a simple case of siblings

We offer a game-theoretic proof of Hamiltons rule for the spread of altruism. For a simple case of siblings, we show that the rule can be derived as the outcome of a one-shot prisoners dilemma game between siblings.JEL Classification: A13, C70, D64Correspondence to: Oded Stark, ZEF, University of Bonn, Walter-Flex-Strasse 3, 53113 Bonn, GermanyWe are indebted to an anonymous referee and to Uwe Cantner for helpful comments and suggestions. Partial financial support from the National Institute on Aging (grant RO1-AG13037) and from the Humboldt Foundation is gratefully acknowledged.     

影响盈余信息含量的因素——来自A股的实证结果

研究中习惯用回报／盈余关系来表示会计盈余的信息含量。通过A股的实证结果发现，当时间窗口为公告日前后60关时，回报／盈余关系较显著；盈余的持续性越高，回报／盈余关系越显著；非线性的模型比线性模型的解释能力更强。但是模型总体的R2水平都较低，这可能是由于研究方法的缺陷、市场的非理性、盈余本身信息含量低等原因造成的。     

THE JOINT ARRIVAL AND DEPARTURE PROCESS FOR THE M/M/l QUEUE

We consider the M/M/1-queue and derive an explicit expression for the joint distribution of the number of arrivals and the number of departures in [0, t), given the number of customers initially present. The derivation is almost purely combinatorial, it avoids the use of generating functions, and immediately yields a simple probabilistic interpretation of the result.     

基于Intranet结构的中小企业MIS构建

知识经济的发展源自于以信息技术、网络技术等高科技及其产业为发展标志的科技革命。中小企业应用Intranet技术，构建企业现代管理信息系统，对提高中小型企业的管理水平和经济效益是十分有益的。     

一种灵活的ADO方式的SQL Server数据连接方法

在基于SQLServer数据系统的C/S开发中,大多数的开发平台与数据库的连接在应用中使用的是固定参数的连接模式,灵活性很差,对于服务器端的可维护性(如服务器更名,IP地址的改变,多数据库系统混合应用等)变得越来越弱,同时维护成本也随之提升,有的甚至服务器系统安装完毕后除了数据备份之外便一直不作任何变动,在安全性和数据库系统混合运用上形成很多不兼容的问题。本文提供了一种基于TCP/IP的客户机与SQLServer连接方法(使用VB开发环境描述),使得无论服务端还是客户端的维护和应用具备高度灵活性也便于安全性维护,同时这种方法也适应于广域网环境的应用。     

Managerial judgment and forecast combination: An experimental study

This paper examines the role of managerial judgment in forming a final forecast, or judging the achievability of a critical level of sales, when multiple forecasts or opinions are available to the decision maker. Several factors that can help improve the quality of human intervention are identified and incorporated in a decision aid. Experimental results show that aided combination can help the decision maker exploit her relevant private information and mitigate the generally observed negative effects of human intervention. Further, the results suggest that emphasizing expected sales, even when the organization is primarily interested in go/no-go decisions, helps improve performance. Several suggestions for future research are presented.

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Problem-solving in teaching/learning packages for Technology

In the project Technology in Secondary Education: Problem-solving in Teaching/learning Packages, two experiments regarding a construction problem and an explanation problem were conducted, in which two variants of a teching/learning package (strongly structuredvs. weakly structured) were compared. Only with the strongly structured instructional variant of the package for the explanation problem did the pupils come to a quick solution of the problem. In both experiments, the factors that influenced the problem-solving processes of the pupils were investigated. The results are of importance for curriculum developers and the authors of teaching/learning packages for Technology but further research into the factors influencing the problem solving process of pupils is necessary.     

我国固定资产投资宏观效益分析

固定资产投资的直接目的是增加固定资产 ,应考察投资和增加固定资产的关系 ,其宏观指标为固定资产交付使用率和项目建成投产率 ;固定资产投资的最终目的是促进经济增长 ,增加国民收入 ,应考察投资和增加国民收入的关系 ,其宏观指标为固定资产投资效益系数或投资系数。我国固定资产交付使用率“七五”时期比“六五”末不断提高 ,“八五”较为平稳 ,“九五”开始回升。我国固定资产投资效益系数“六五”以来较为平稳 ,“八五”较高 ,“九五”下滑幅度较大。应采取多种措施 ,不断提高投资效益。