基于回归分析确定中间产品价格

中间产品如何合理定价是项目经济效益评价的一个难点。文章以干气法生产苯乙烯为例,探讨通过多元线性回归模型,由原料苯和产品苯乙烯价格推导中间产品乙苯价格的方法。     

引入MATLAB进行线性代数教学的探究

分析了我国线性代数教学的现状,提出了在线性代数教学中结合MATLAB软件教学,并讨论题必要性,首先应用MATLAB在线性代数教学中可以使得抽象问题形象化;其次应用数学知识对实际问题进行建模通过数学软件使得求解变为可能;这些都以实际例子加以解释说明。最后提出结合Matlab进行线性代数教学以后的发展方向和存在的困难。     

Non-permutation flowshop scheduling in a supply chain with sequence-dependent setup times

In this paper, we consider a flowshop scheduling problem with sequence-dependent setup times and a bicriteria objective to minimize the work-in-process inventory for the producer and to maximize the customers' service level. The use of a bicriteria objective is motivated by the fact that successful companies in today's environment not only try to minimize their own cost but also try to fulfill their customers' need. Two main approaches, permutation and non-permutation schedules, are considered in finding the optimal schedule for a flowshop. In permutation schedules the sequence of jobs remains the same on all machines whereas in non-permutation schedule, jobs can have different sequence on different machines. A linear mathematical model for solving the non-permutation flowshop is developed to comply with all of the operational constraints commonly encountered in the industry, including dynamic machine availabilities, dynamic job releases, and the possibility of jobs skipping one or more machines, should their operational requirements deem that it was necessary. As the model is shown to be NP-hard, a metasearch heuristic, employing a newly developed concept known as the Tabu search with embedded progressive perturbation (TSEPP) is developed to solve, in particular, industry-size problems efficiently. The effectiveness and efficiency of the search algorithm are assessed by comparing the search algorithmic solutions with that of the optimal solutions obtained from CPLEX in solvable small problem instances.     

基于多元线性回归的上海市生产性服务业和汽车产业发展的关联分析

生产性服务业是上海市“十二五”重点发展产业,“十二五”期间是上海市汽车产业的关键时期,发展基于汽车行业的生产性服务业将有效促进上海市两大关键产业的发展.从上海市生产性服务业和汽车产业发展的实践出发,基于生产性服务业和汽车行业的关联性概念模型,应用多元线性回归技术,通过对上海市生产性服务业、汽车产业及其外部环境因素的多元线性回归,论文研究了上海市生产性服务业、汽车产业和外部环境的数量关联及其含义.     

土地经营规模对农户种粮收入的影响分析——以吉林省公主岭市为例

土地是财富之母,土地作为农民进行农业生产的基本生产资料,是农民收入来源的重要依托。家庭联产承包责任制实施至今虽然取得很大成就,但是以家庭经营为主的传统经营方式弊端日益显现,农民种粮收入难以实现有效增长。[目的]为了达到农村土地适度规模经营,调整农村产业结构、促进农民增收、加快小城镇建设等目的。[方法]通过选取产粮大县公主岭市为研究对象,利用实地调研数据对不同土地经营规模下的种粮成本及利润水平进行比较,并运用c-D生产函数对数据进行多元线性回归分析。[结果]从种植成本来看,5~20hm~2中等经营规模投入的综合成本低于5hm~2以下小规模和20hm~2以上大规模经营;从利润来看,5~20hm~2中等经营规模无论是自有承包地还是转包地所获得的每667m~2平均利润均高于小规模和大规模的经营规模。[结论]公主岭市农户土地经营面积为5~20hm~2的中规模优于其他土地经营规模。同时运用多元线性回归模型分析其对农户种粮收入的影响程度,进一步证实土地经营规模对农民种粮收入具有积极促进作用。从而提出推进公主岭市土地适度规模经营的对策建议。     

独立学院线性代数教学改革的探索

线性代数是理工科专业必修的一门基础课,该课程为学生学习专业知识提供必要的基础,具有较强的应用性,提高学生的抽象思维和逻辑思维能力。本文从提高学生学习线性代数的兴趣着眼,主要对独立学院线性代数的教学内容、教学方法及教学手段改革的探索。     

The out-of-sample forecasting performance of nonlinear models of regional housing prices in the US

This article provides out-of-sample forecasts of linear and nonlinear models of US and four Census subregions’ housing prices. The forecasts include the traditional point forecasts, but also include interval and density forecasts, of the housing price distributions. The nonlinear smooth-transition autoregressive model outperforms the linear autoregressive model in point forecasts at longer horizons, but the linear autoregressive and nonlinear smooth-transition autoregressive models perform equally at short horizons. In addition, we generally do not find major differences in performance for the interval and density forecasts between the linear and nonlinear models. Finally, in a dynamic 25-step ex-ante and interval forecasting design, we, once again, do not find major differences between the linear and nonlinear models. In sum, we conclude that when forecasting regional housing prices in the United States, generally the additional costs associated with nonlinear forecasts outweigh the benefits for forecasts only a few months into the future.     

Negative affectivity and workplace deviance: the moderating role of ethical climate

This study investigates (1) the relationship between employees’ trait of negative affectivity (NA) and workplace deviance and (2) the moderating role of ethical climate in the above relationship. Data was collected from 310 employees in 40 Taiwanese companies, and hierarchical linear modeling was used to test the hypotheses. Results show that NA was positively related to workplace deviance. In addition, the rules climate weakened the relationship between NA and workplace deviance, and both the instrumental climate and the caring climate strengthened the relationship between NA and workplace deviance. Managerial implications and future research directions are also discussed.     

The importance of the firm and destination effects to explain firm performance

An interesting question in tourism management is why tourist firms obtain different performance levels. Firm performance in the tourism industry depends mainly on the destination where the company operates (location or destination effect), and on firm internal resources and characteristics (firm effect). The purpose of this paper is to determine the relative importance of the firm and destination effects using a multilevel approach and hierarchical linear models. The findings show that both effects impact significantly on firm performance, and also that the firm effect is more important than the destination effect. We equally provide some insights about the relationships between these two levels with the aim of building bridges between them.     

高科技风投企业家项目考察阶段的非理性决策实证研究——基于人口统计特征分析

基于人口统计特征,采用列联表和多元线性回归的方法分析人口统计特征中有关的年龄、学历、留学经历与家庭结构等要素与高科技风投企业家非理性行为在项目考察阶段决策的相关性结果显示:国外留学经验、创业成功经验与企业家项目考察阶段的非理性决策存在着相关性。