基于极值分布的离散选择模型尺度参数  

Scale parameter of discrete choice model based on extreme value distribution

作　　者：郑柯[1] 郑勇[2] 

机构地区：[1]湖南大学土木工程学院,湖南长沙410082 [2]山西省交通科学研究院,山西太原030006

出　　处：《交通运输工程学报》2009年第1期92-95,共4页Journal of Traffic and Transportation Engineering

基　　金：国家西部交通建设科技项目(200731800003)

摘　　要：为了准确把握尺度参数在模型建模、分析以及应用过程中的作用,以基于极值分布的Multinomial Logit模型和Nested Logit模型为研究对象,从建模的基础——误差项的分布形式入手,通过模型形式和误差项性质两方面研究了尺度参数在两种模型中的特性,并对其进行了对比分析。分析结果表明:尺度参数不仅限制了模型效用函数的尺度,而且也反映了误差项的方差水平,但对于以上两种不同的模型,其在尺度限制、误差项方差水平及独立性、自身取值范围等方面均表现出不同的特性,Multinomial Logit模型的尺度参数反映了有关整个效用确定项的误差项方差水平,而Nested Logit模型的尺度参数只是反映了与某一选择枝有关的部分效用确定项的误差项方差水平。In order to understand the role of scale parameter in the process of modeling, analysis and application, multinomial logit model and nested logit model were discussed based on extreme value distribution. Starting with the distribution of error terms, the properties of scale parameter in two models were studied in aspects of model expressions and error term properties, and a comparison analysis was made. Analysis result shows that scale parameter not only restricts the scale of utility function, but also reflects the variance of error terms. However, it reveals different properties at two different models in terms of scale restriction, variance and independenee degree of error terms, and numerical areas. For multinomial logit model, the scale parameter reflects the variance of entire error terms, while for nested logit model, it only reflects the variance of a part concerning the observed term for a specific alternative. 1 tab, 10 refs.

关 键 词：交通规划 离散选择模型 LOGIT模型 Nested LOGIT模型 尺度参数 

分 类 号：U491.1[交通运输工程—交通运输规划与管理]