Contemporary Extensions of the Rasch Model

This paper will introduce, discuss and illustrate two contemporary extensions of theRasch model: the one parameter logistic model (Verhelst and Glas, 1995) and theMultidimensional Rasch model (Hoijtink et al., 1999). Using data with respect tothe measurement of schizotypy (Vollema and Hoijtink, 2000) the most importantfeatures of both models will be illustrated. For the one parameter logistic modelthese include: a (discrete) discrimination parameter for each item; a test for itembias; and, estimation of the location of a person on the (latent) trait that is beingmeasured. For the multidimensional Rasch model these include: specification ofthe model; and, model selection. All analyses presented in this paper can be executedusing either OPLM (Verhelst et al., 1995), TESTFACT (Wilson et al.,1984) or ConQuest (Wu et al., 1998). At the end of the paper some features ofmodels and software that have not been discussed will be summarized.     

Potential user factors driving adoption of IPTV. What are customers expecting from IPTV?

Internet Protocol Television (IPTV), the convergence services of television and Internet, is being rapidly developed around the world. The advent of digital technologies has changed the convergence market dramatically with the wide diffusion of the convergent services. Using the Technology Acceptance Model as a conceptual framework and method of logistic regression, this research analyzes the demand for IPTV by drawing data from 452 consumers. Individuals' responses to questions about whether they accept IPTV are collected and combined with observations of their socio-economic status and intrinsic/extrinsic factors modified from the Technology Acceptance Model. Results of logistic regression show two variables (intrinsic and extrinsic factors) that seem to explain what influences consumer behavior towards adopting IPTV. Overall, the logistic regression model explains over 50% of the variance in the IPTV adoption. The variances shed light on the multi-open platform environment that IPTV will forge.     

天津物流业基础设施及发展水平统计分析

物流业是天津市重点发展的支柱型产业.本文旨在介绍天津物流业的现状,并对物流产业水平进行系统的统计分析,为宏观物流政策的制定提供依据.     

上市公司关联交易盈余管理实证研究

文章以科技类上市公司为研究样本,运用Logistic(逻辑斯蒂)回归模型对关联交易盈余管理的原因和特征进行了分析。研究结果显示:连续三年没有增发新股和配股的上市公司,其再筹资动机强烈;上市公司的大股东及其关联方占用上市公司大量资金;上市公司关联担保现象严重;大股东及其关联方不仅通过非主营业务管理盈余,而且还通过主营业务管理盈余。     

Technological change in energy systems: Learning curves, logistic curves and input-output coefficients

Learning curves have recently been widely adopted in climate-economy models to incorporate endogenous change of energy technologies, replacing the conventional assumption of an autonomous energy efficiency improvement. However, there has been little consideration of the credibility of the learning curve. The current trend that many important energy and climate change policy analyses rely on the learning curve means that it is of great importance to critically examine the basis for learning curves. Here, we analyse the use of learning curves in energy technology, usually implemented as a simple power function. We find that the learning curve cannot separate the effects of price and technological change, cannot reflect continuous and qualitative change of both conventional and emerging energy technologies, cannot help to determine the time paths of technological investment, and misses the central role of R&D activity in driving technological change. We argue that a logistic curve of improving performance modified to include R&D activity as a driving variable can better describe the cost reductions in energy technologies. Furthermore, we demonstrate that the top-down Leontief technology can incorporate the bottom-up technologies that improve along either the learning curve or the logistic curve, through changing input-output coefficients. An application to UK wind power illustrates that the logistic curve fits the observed data better and implies greater potential for cost reduction than the learning curve does.     

考虑违约距离的上市公司危机预警模型研究

在上市公司财务危机预警中,违约距离起着重要的不可替代的作用,仅考虑财务指标并不足以完全解释企业财务危机发生的原因.文章应用Merton模型对2002～2004年ST公司和相应配对公司的危机发生之前的违约距离进行了研究,发现危机公司违约距离在危机发生前第三年明显低于正常公司的相应值,违约距离比传统财务指标能更早地预警到企业财务危机的发生.结合违约距离因素的危机预警模型能更明显地提高模型的危机判断正确率.     

Application of logistic analysis to the history of physics

Recently, two analyses have tried to put technological progress in a larger context. One interpretation hypothesizes that technological progress is likely to continue at increasingly higher rates of change. Another interpretation, which includes data from the beginning of the universe to the present, suggests that the universe is approaching a transition point in a logistic development of complexity. This logistic development is similar to the way ideas or products diffuse in a population, i.e., the rate of discovery in a field of knowledge is proportional to the amount discovered and the amount to be discovered. To test a part of this hypothesis, a leading indicator field (fundamental physics) was identified and the events in the history of this field were analyzed. Twelve subfields were identified and grouped into six stages. Each stage seemed to demonstrate a logistic-like development. By analyzing both the median time of development and the characteristic time of development of these stages, the overall development of this one field was found to suggest logistic development. These data seem to indicate that development in fundamental physics is slowing down, with at least one subfield beyond string physics yet to be developed. The data tend to support the hypothesis that a knowledge field can develop logistically.     

中国电子商务企业生存的实证分析

本文通过Logisitc回归模型，对电子商务企业生存的影响因素进行了分析。笔者认为，电子商务企业的生存是受企业自身基因构成决定的，而电子商务企业的基因构成包括了企业家才能、资金、信息资本、人力资本、社会资本和技术资本。同时，企业的基因会随着环境的变化而不断地进行着调整和整合，以适应竞争的需要。实证分析的结果证实了笔者的判断。     

A logistic regression point of view toward loss given default distribution estimation

We propose a new procedure to estimate the loss given default (LGD) distribution. Owing to the complicated shape of the LGD distribution, using a smooth density function as a driver to estimate it may result in a decline in model fit. To overcome this problem, we first apply the logistic regression to estimate the LGD cumulative distribution function. Then, we convert the result into the LGD distribution estimate. To implement the newly proposed estimation procedure, we collect a sample of 5269 defaulted debts from Moody’s Default and Recovery Database. A performance study is performed using 2000 pairs of in-sample and out-of-sample data-sets with different sizes that are randomly selected from the entire sample. Our results show that the newly proposed procedure has better and more robust performance than its alternatives, in the sense of yielding more accurate in-sample and out-of-sample LGD distribution estimates. Thus, it is useful for studying the LGD distribution.     

锚企业与科技新城共生模式研究:以阿里巴巴和杭州未来科技城为例

以阿里巴巴和杭州未来科技城为例，采用Logistic模型探讨锚企业与科技新城共生模式，结果表明：总体而言，阿里巴巴和未来科技城属于互利共生模式，阿里巴巴成长会促进未来科技城发展，而未来科技城发展也会反哺阿里巴巴的成长。2013-2016年两者共生系数之间的差值不断缩小，表明阿里巴巴和杭州未来科技城的共生模式从偏利共生转向互利共生。