遗传算法及其在客户关系管理中的应用研究

遗传算法是一种宏观意义下的仿生优化算法，它模拟生物在自然环境中的遗传和进化过程而形成的一种自适应全局优化概率搜索算法。这种算法可以用于对海量的客户信息进行搜索，提取对决策有用的信息，让企业在激烈的市场竞争中处于有利地位，最终达到最高利润。本文还通过一个简单的实例研究将该算法应用在客户关系管理中。     

Characteristics and implications of Chinese macroeconomic data revisions

The research examining macroeconomic data for developed economies suggests that an understanding of the nature of data revisions is important both for the production of accurate macroeconomic forecasts and for forecast evaluation. This paper focuses on Chinese data, for which there has been substantial debate about data quality for some time. The key finding in this paper is that, while it is true that the Chinese macroeconomic data revisions are not well-behaved, they are not very different from similarly-timed U.S. macroeconomic data revisions. The positive bias in Chinese real GDP revisions is a result of the fast-growing service sector, which is notably hard to measure in real time. A better understanding of the revisions process is particularly helpful for studies of the forecast errors from surveys of forecasters, where the choice of the vintage for outcomes may have an impact on the estimated forecast errors.     

The effects of handling outliers on the performance of bankruptcy prediction models

Ratio type financial indicators are the most popular explanatory variables in bankruptcy prediction models. These measures often exhibit heavily skewed distribution because of the presence of outliers. In the absence of clear definition of outliers, ad hoc approaches can be found in the literature for identifying and handling extreme values. However, it is not clear how these different approaches can affect the predictive power of models. There seems to be consensus in the literature on the necessity of handling outliers, at the same time, it is not clear how to define extreme values to be handled in order to maximize the predictive power of models. There are two possible ways to reduce the bias originating from outliers: omission and winsorization. Since the first approach has been examined previously in the literature, we turn our attention to the latter. We applied the most popular classification methodologies in this field: discriminant analysis, logistic regression, decision trees (CHAID and CART) and neural networks (multilayer perceptron). We assessed the predictive power of models in the framework of tenfold stratified crossvalidation and area under the ROC curve. We analyzed the effect of winsorization at 1, 3 and 5% and at 2 and 3 standard deviations, furthermore we discretized the range of each variable by the CHAID method and used the ordinal measures so obtained instead of the original financial ratios. We found that this latter data preprocessing approach is the most effective in the case of our dataset. In order to check the robustness of our results, we carried out the same empirical research on the publicly available Polish bankruptcy dataset from the UCI Machine Learning Repository. We obtained very similar results on both datasets, which indicates that the CHAID-based categorization of financial ratios is an effective way of handling outliers with respect to the predictive performance of bankruptcy prediction models.     

A new method for measuring congestion in data envelopment analysis

In data envelopment analysis (DEA), there are two principal methods for identifying and measuring congestion: Those of Färe et al. [Färe R, Grosskopf S. When can slacks be used to identify congestion. An answer to W. W. Cooper, L. Seiford, J. Zhu. Socio-Economic Planning Sciences 2001;35:1–10] and Cooper et al. [Cooper WW, Deng H, Huang ZM, Li SX. A one-model approach to congestion in data envelopment analysis. Socio-Economic Planning Sciences 2002;36:231–8]. In the present paper, we focus on the latter work in proposing a new method that requires considerably less computation. Then, by proving a selected theorem, we show that our proposed methodology is indeed equivalent to that of Cooper et al.     

An environmental performance index for products reflecting damage costs

Several studies have demonstrated how to use DEA (Data Envelopment Analysis) based techniques to estimate environmental performance indices. None of these studies, however, are taking information on the environmental damage costs of the pressure types considered into account. This study is bridging a gap between environmental indices founded in physical pressures and damage costs founded in welfare economics. The aim of the paper is twofold: first, to demonstrate how to implement the information on environmental damage costs within a DEA based environmental performance index, and second, to estimate these indices at product level by using Danish input-output data and environmental data from 1997.     

Dynamic environmental performance analysis: A Malmquist index approach

This article presents a general framework for dynamic environmental performance analysis by generalizing the approach proposed by Kuosmanen and Kortelainen [Kuosmanen, T., Kortelainen, M., 2005. Measuring Eco-Efficiency of Production with Data Envelopment Analysis. Journal of Industrial Ecology 9(4), 59-72.] from a static to a dynamic setting. For this purpose we construct an environmental performance index (EPI) by applying frontier efficiency techniques and a Malmquist index approach. Compared to other dynamic environmental productivity and efficiency analysis approaches based on these methods, our approach builds on the standard definition of eco-efficiency as it is presented in the ecological economics literature. Recognizing the importance to analyze the sources of environmental performance changes, we show how changes in overall environmental performance can be decomposed into changes in relative eco-efficiency and shifts in environmental technology, respectively. We apply the presented technique at the macro level to dynamic environmental performance analysis of 20 member states of the European Union in 1990-2003. According to the results, environmental technical change mostly explains the improvement in overall environmental performance, while relative eco-efficiency change has been minor for most countries during the sample period.     

Competition and public high school performance

Increasing the level of school competition has been suggested as a way to improve school performance. This study examines one of the most extreme examples of such reform using data from New Zealand public high schools. In the 1990s school zoning was abolished in New Zealand and public schools competed for students, not just with private schools, but also with each other. A categorical Data Envelopment Analysis model using data on school resources and student academic performance, stratified using student socio-economic characteristics, is used to calculate efficiency scores for schools. A regression model is then used to analyse differences in these efficiency scores and their relationship to different levels of competition.     

烟草商业企业数字仓库的基本流程与系统功能设计研究

数字仓库的应用将协助企业保证供应、压缩库存、提高货物周转效率、节约成本。本文介绍了数字仓库的概念,研究了烟草商业企业数字仓库的基本流程与系统功能结构与设计,并对数字仓库的效益进行了评价。对这些问题的深入研究将有利于提高烟草商业企业的物流水平和服务效率。     

基于PDM系统的产品研发过程项目管理

在对企业产品研发过程和项目管理进行分析的基础上,提出了基于PDM系统的产品研发过程项目管理解决方案。通过建立PDM系统中产品研发过程项目管理模型,实现了对产品研发过程管理的综合描述,保证了对项目运行过程中的任务进行管理和监控。     

DEA evaluations of long- and short-run efficiencies of digital vs. physical product “dot com” companies

This paper applies Data Envelopment Analysis to determine relative efficiencies between internet dot com companies that produce only physical products and those that produce only digital products. To allow for the fact that the latter are relatively inexperienced, a distinction is made between long- and short-run efficiencies and inefficiencies, with a finding of no statistically significant difference in the short run but digital product companies are significantly more efficient in the long run. A new way of distinguishing between long- and short-run performances is utilized that avoids the need for identifying the time periods associated with long-run vs. short-run efficiencies and inefficiencies. In place of “time,” this paper utilizes differences in the “properties” that economic theory associates with long- and short-run performances.