Optimal pest control in agriculture

Based on economic methodology we model an ecosystem with two species in predator–prey relationship: mice feed on grain and grain feeds on a resource. With optimizing behavior of individual organisms a short-run ecosystem equilibrium is defined and characterized that depends on the farmer's use of fertilizer and pesticide and on the mice population which, in turn, is affected by pesticides. In that way, a microfounded agricultural production function is derived. Linking a sequence of short-run ecosystem equilibria yields the growth function of the mice population which is thus derived rather than assumed. In each period the farmer harvests all grain in excess of some given amount of seed. If she maximizes her present-value profits, optimal farming is characterized by either using no pesticide or a moderate amount of pesticide or by applying a chattering control. Pest eradication is never optimal. On the other hand, if the farmer takes into account steady-state mice populations only, it may be optimal to eradicate mice or to use no or a moderate amount of pesticide depending on prices as well as on the shape of the grain production function which is determined by microparameters of grain reproduction.     

浅析网络信息安全技术

文章总结分析了网络信息的几种安全技术,并简要叙述了安全技术的具体应用。     

西方管理控制理论比较与启示

管理控制理论的研究在西方国家已有200余年的历史，了解其发展历史并总结管理控制理论的研究趋势，对于我国发展管理控制理论、改进管理控制实践具有重要意义。本文在对管理控制思想的源起与发展脉络、不同学派管理控制概念的比较与差异以及管理控制系统框架的比较与差异进行探讨的基础上，得出了未来管理控制理论研究的发展趋势。     

基于多元统计分析的封闭式基金业绩评价

本文引入在险价值(VaR)和基金折价率指标,利用因子分析和聚类分析方法对基金业绩进行综合评价。实证分析发现我国封闭式基金收益率优于市场收益率,少数几只基金业绩相对突出,实现低风险高收益的目标。但封闭式基金折价幅度较大,基金内部收益水平与外部评价状况背离,反映了市场投资者的投资非理性现象。     

Distribution-free tests for comparing several treatments with a control

Abstract  In this paper we propose distribution-free treatments versus control tests for the one- and two-way classifications. The null distribution properties are shown to be equivalent to those of well-known statistics for which critical values have been extensively tabled. Asymptotic relative efficiencies with respect to corresponding normal theory competitors are derived and optimal designs for the allocation of experimental units to the treatments and control are obtained.     

The housing question in Japan

This article first examines how bad housing conditions are in Japan based on international comparisons. The next question is whether the extremely high land prices in Japan can be explained by economic logic. We then turn to more specific housing policy questions that are peculiar to or important in Japan, such as the tax advantages of owning land that have caused under-utilization of land and the reasons why the average size of Japanese rental housing is so small.     

建筑外墙氟碳涂料施工的质量监控

建筑外墙氟碳涂料克服了以往氟碳涂料不能常温固化的缺点，能应用于混凝土等无机材质的表面。由于其具有超耐候性等卓越性能，已受到业主、设计的关注和市场的认可，在外墙饰面中将得到广泛应用。文章浅析了外墙氟碳涂料的材料特性，阐述了外墙氟碳涂料施工阶段的质量事前控制、事中控制和事后控制；对某工程外墙氟碳涂料施工质量缺陷产生的原因进行了分析，提出了相应的预控措施。     

经济生产量模型对库存的控制

在分析需求变化的基础上修改和完善了经济批量模型,进一步研究了单项物品和多项物品的最小经济生产批量以及年最小总成本,改进了经济生产量模型。     

倒排计划和安全库存计划相结合的物料需求计划与控制方法--用于非定型产品制造业

介绍生产非定型产品企业的物料需求计划与控制的原则，根据制造业企业的物料整体逻辑流程图，找出影响物料需求计划与控制的各个因素，提出合理实效的需求计划与控制方法并以实例加以说明。