理解障碍和《高等数学》教学困难及对策

该文从数学理解的高度,分析了数学学习困难的课程内在原因和当前教育体制的局限性,以及克服这些障碍的一些对策。理解在数学学习中占有重要的地位,因此数学理解障碍是数学学习中的一种重要障碍,如果不注重学生是否具有理解的意向,不了解学生的认知水平,就不能帮助学生克服障碍。在教学上,可以通过创设恰当、有趣的教学情境、帮助学生生成正确的数学表象、注重数学交流等途径来排除理解障碍。     

Manure Applications and Nutrient Standards

Because of environmental concerns, many states are regulating animal manure applications to crops. A conceptual model is presented to describe manure demand for crop nutrient application under alternative regulatory standards. Demand relationships are incorporated into a spatial equilibrium model to estimate welfare costs of phosphorus and nitrogen regulatory standards for manure applications. Model estimates for Virginia indicate that regulatory standards for manure application achieve large reductions in excess nitrogen and phosphorus and result in 5–15% welfare losses excluding nonmarket environmental valuation.     

Optimal Recycling System Design: With an Application to Sophisticated Packaging Tools

This paper deals with the mathematical analysis of product-process chains, aimed at the proper design of recycling systems. A modelling method is presented that can be applied to various chains. It is applied to a case in which a producer of sophisticated packaging tools requires insight into the many options of the design of a reuse/recycling chain. This is due to expectations for the near future that are related to extended product responsibility and the enforcement of recycling. Depending on the weight of different criteria and the choice of systems boundaries, optimal solutions can be selected. It turns out that the modelling method acts as a useful decision tool. A major bottleneck is the availability of data from suppliers and customers.     

马克思劳动价值理论的数理表达与创新——兼析马克思主义价值生产模型与西方使用价值生产模型的沟通

本文首先依据马克思劳动价值论归纳了这一理论的基本假定条件,并在这些假定条件下构建了马克思劳动价值数理模型;其次根据现时代经济发展变化的现实,改变了马克思劳动价值论的一些约束条件,并在这一条件下重新构建了劳动价值理论模型,并进而探讨了技术进步条件下的动态模型。最后探讨马克思主义价值生产模型与西方经济学生产模型的沟通与连接的问题。     

劳动价值论的数学模型分析:方法论特性与建构

马克思主义政治经济学方法是实践观指导下的科学的抽象分析法。劳动价值论的实质是唯物史观方法论的不断转化和科学运用,具体化形式是哲学思维分析与数学模型分析的统一,从而构成经济本质分析与经济运行分析统一的基础。具体而言,价值创造及运行对应了微观层面的价值(经济)本质分析和价值(经济)运行分析的统一,价值决定及其运行对应了宏观层面的价值(经济)本质分析和价值(经济)运行分析的统一。在当前,劳动价值论的数学模型分析需要更加广义化和应用化,以增强实际运用价值。     

Job offers of multi-national accounting firms: the effects of emotional intelligence,extra-curricular activities,and academic performance

This study investigates the effects of academic performance, extracurricular activities (ECA) and emotional intelligence (EI) of potential accounting-major graduates on the outcomes of their respective interviewing activities and the number of final job offers given by the multinational Big 5 public accounting firms. The following outcomes are identified: (a) the number of initial job interviews is affected by both a graduate's academic performance and level of participation in ECA; (b) the number of subsequent job interviews is affected by both the number of initial job interviews as well as the level of a graduate's EI; (c) the number of final job offers is affected by the graduate's level of EI and both the number of initial and subsequent job interviews. The results indicate the relevance of EI in the job search process and will also be useful for accounting educators to plan their curricula more effectively to enhance the job placement of their graduates with the Big 5 firms.     

Timing Movie Release on the Internet in the Context of Piracy

Offering movies on the Internet is one way of combating the issue of online movie piracy, although the tradeoff is the cannibalization of the more revenue-generating channels. Given this tradeoff and the rather unique “staggered window distribution” mechanism followed by the movie industry, this article addresses the problem of when the studio owner should release the movie online to maximize the entire revenue stream of that movie. A general modeling approach that assumes an exponential demand function and fixed release times in the remaining channels is provided. Detailed illustration using three different movie types demonstrates that a high revenue-generating movie should be released online just prior to its home video release, while the online release of an average or below-average movie should coincide with their withdrawal from the theaters. Sensitivity analyses of the results are also displayed and give the circumstances under which a different online release time is warranted. The analysis suggests, among other things, that if a movie has an excellent opening strength and is able to sustain its revenues quite well, it would be more profitable to release the movie online a few weeks before it is withdrawn from the theaters. Additionally, the standard outcomes generated by the model are found to be sensitive to any online per-unit price change.     

数字温度指示调节仪测量不确定度评定

本文介绍了数字温度指示调节仪测量不确定度评定的测量方法,数学模型,标准不确定度评定,合成标准不确定度评定以及扩展不确定度的评定。     

单参数航空发动机性能衰退评估数学模型的建立

航空发动机是各种飞机的动力装置主要组成部分,被称为飞行器"心脏"。作为机械与电子高度融合的航空发动机,在使用过程中性能会出现不同程度的衰退。但如何方便快捷地计算出衰退的进程及其程度是很困难的。为解决这一难题,在性能衰退评估中采用排气温度这一单一参数,并建立其有关数学模型,简便有效地解决使用中的困惑。     

服装缝纫流水线的负荷优化编排

提出一种服装缝纫流水线负荷平衡的编排方法。利用工序分析表,得到各个工序的工作时间、所使用的机械种类以及各个工序之间加工的优先逻辑关系。建立相应的数学模型,依据数学模型编辑相应程序。利用线性规划软件Lingo求解,得到最优化的工位数、生产节拍以及各个工序之间的编组。