• Title, Summary, Keyword: 로짓모형

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Development and Application of the Heteroscedastic Logit Model (이분산 로짓모형의 추정과 적용)

  • 양인석;노정현;김강수
    • Journal of Korean Society of Transportation
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    • v.21 no.4
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    • pp.57-66
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    • 2003
  • Because the Logit model easily calculates probabilities for choice alternatives and estimates parameters for explanatory variables, it is widely used as a traffic mode choice model. However, this model includes an assumption which is independently and identically distributed to the error component distribution of the mode choice utility function. This paper is a study on the estimation of the Heteroscedastic Logit Model. which mitigates this assumption. The purpose of this paper is to estimate a Logit model that more accurately reflects the mode choice behavior of passengers by resolving the homoscedasticity of the model choice utility error component. In order to do this, we introduced a scale factor that is directly related to the error component distribution of the model. This scale factor was defined so as to take into account the heteroscedasticity in the difference in travel time between using public transport and driving a car, and was used to estimate the travel time parameter. The results of the Logit Model estimation developed in this study show that Heteroscedastic Logit Models can realistically reflect the mode choice behavior of passengers, even if the difference in travel time between public and private transport remains the same as passenger travel time increases, by identifying the difference in mode choice probability of passengers for public transportation.

A Store Choice Model for an Entry Strategy of New Stores: An Application of the Mother Logit Model (신규점포의 진입전략을 위한 점포선택모형: mother 로짓모형의 적용)

  • 김근배;박동준;서봉철
    • Journal of Distribution Research
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    • v.4 no.3
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    • pp.47-64
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    • 2000
  • This study introduces the mother logit model to predict consumer's store choices. The model is not based on the IIA assumptions and thus accounts for substitution among similar alternatives. The choice data as an input to the model is obtained through the conjoint-type choice experiment. The model is applied to consumer's choice of fastfood stores in the context where new store enters the market. The analysis shows that the substitution effects are significant and therefore the mother logit model predicts better than the IIA model. The mother logit model will be useful as well for the market structure analysis in capturing cannibalization among several brands.

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Effects of Multicollinearity in Logit Model (로짓모형에 있어서 다중공선성의 영향에 관한 연구)

  • Ryu, Si-Kyun
    • Journal of Korean Society of Transportation
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    • v.26 no.1
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    • pp.113-126
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    • 2008
  • This research aims to explore the effects of multicollinearity on the reliability and goodness of fit of logit model. To investigate the effects of multicollinearity on the multinominal logit model, numerical experiments are performed. The exploratory variables(attributes of utility functions) which have a certain degree of correlations from (rho=) 0.0 to (rho=) 0.9 are generated and rho-squares and t-statistics which are the indices of goodness of fit and reliability of logit model are traced. From the well designed numerical experiments, following findings are validated : 1) When a new exploratory variable is added, some of rho-squares increase while the others decrease. 2) The higher relations between generic variables lead a logit model worse with respect to goodness of fit. 3) Multicollinearity has a tendency to produce over-evaluated parameters. 4) The reliability of the estimated parameter has a tendency to decrease when the correlations between attributes are high. These results suggest that we have to examine the existence of multicollinearity and perform the proper treatments to diminish multicollinearity when we develop logit model.

An Analysis of Choice Behavior for Tour Type of Commercial Vehicle using Decision Tree (의사결정나무를 이용한 화물자동차 투어유형 선택행태 분석)

  • Kim, Han-Su;Park, Dong-Ju;Kim, Chan-Seong;Choe, Chang-Ho;Kim, Gyeong-Su
    • Journal of Korean Society of Transportation
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    • v.28 no.6
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    • pp.43-54
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    • 2010
  • In recent years there have been studies on tour based approaches for freight travel demand modelling. The purpose of this paper is to analyze tour type choice behavior of commercial vehicles which are divided into round trips and chained tours. The methods of the study are based on the decision tree and the logit model. The results indicates that the explanation variables for classifying tour types of commercial vehicles are loading factor, average goods quantity, and total goods quantity. The results of the decision tree method are similar to those of logit model. In addition, the explanation variables for tour type classification of small trucks are not different from those for medium trucks', implying that the most important factor on the vehicle tour planning is how to load goods such as shipment size and total quantity.

Analysis of Prework Trip-Making and Modal Choice (통근통행 이전의 비통근통행 발생여부와 교통수단 선택행태 분석)

  • 윤대식
    • Journal of Korean Society of Transportation
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    • v.17 no.5
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    • pp.57-65
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    • 1999
  • 본 연구에서는 지금가지 통근통행자의 활동참여 분석(activity Participation analysis)이 주로 일과후 활동참여(postwork activity participation)에 초점이 주어졌다는 점을 감안하여 일과전 활동참여(preworkactivity Participation)를 분석하고자 하였다. 이러한 연구배경하에서 본 연구는 통근통행자의 통근통행 이전의 비 통근통행 발생여부와 교통수단 선택의 행태를 네스티드 로짓모형을 이용하여 분석하였다. 본 연구는 모형의 경험적 추정을 위해 1995년 미국 Nationwide Personal Transportation Survey (NPTS)의 일부분으로 수집된 뉴욕 대도시지역의 설문조사자료를 이용하였으며, 추정된 경험적 모형을 바탕으로 의미 있는 결과를 논의하였다. 본 연구에서 추정된 통근통행 이전의 비 통근통행 발생여부와 교통수단 선택의 네스티드 로짓모형은 통계적 측면이나 행태적 측면에서 볼 때 대체로 타당한 분석결과를 보여준다. 교통수단 선택모형(조건부 모형)의 추정결과를 보면 나이, 운전면허 소지여부, 가구내 차량보유대수, 가구내 직장인수, 연간 가구소득, 교통수단의 통행시간이 통근통행자의 교통수단 선택에 의미 있는 영향을 미치는 것으로 확인되었다. 한편 통근통행 이전의 비통근통행 발생여부 선택모형(한계모형)의 추정결과를 보면 나이 성별, 가구내 차량보유대수, 가구의 생애주기가 통근통행자의 비 통근통행 발생여부에 의미 있는 영향을 미치는 것으로 확인되었다. 본 연구로부터의 중요한 발견은 추정된 네스티드 로짓모형의 inclusive value의 추정계수값을 살펴봄으로써 가능한데, 모형의 경험적 추정결과는 본 연구에서 가설화된 네스티드 로짓모형구조의 타당성을 입증시켜 준다. 아울러 직장인의 교통수단 선택은 통근통행 이전의 비 통근통행 발생여부의 선택과 밀접한 관련을 가지면서 이루어진다는 사실을 확인할 수 있었다.

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Analysis of Urban Workers' Travel Pattern Choice Behavior (통근통행자의 통행패턴 선택행태의 분석)

  • 윤대식
    • Journal of Korean Society of Transportation
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    • v.15 no.4
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    • pp.35-51
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    • 1997
  • The main objective of this research is to develop urban workers' daily travel pattern choice model. For this research, a hovel pattern choice model was empirically estimated by using a survey data collected from Kyongsan and Yeungchun City. For this research, a nested logit model structure was employed. For the model specification, it is hypothesized that urban workers' daily travel pattern choice behavior is represented by two stages of choices with single-destination or multi destination travel pattern choice as the higher stage, and the number of tours as the lower stage. The urban workers' daily travel pattern choice model developed in this research yields intuitively reasonable results. From the empirical results, it is found to be sensible to represent urban workers' daily travel patterns as the nested logit model structure Hypothesized in this research. furthermore, future directions of model development are suggested.

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Comparison of Some Nonparametric Statistical Inference for Logit Model (로짓모형의 비모수적 추론의 비교)

  • 정형철;김대학
    • The Korean Journal of Applied Statistics
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    • v.15 no.2
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    • pp.355-366
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    • 2002
  • Nonparametric statistical inference for the parameter of logit model were examined. Usually nonparametric approach is milder than parametric approach based on normal theory assumption. We compared the two nonparametric methods for legit model, the bootstrap and random permutation in the sense of coverage probability. Monte Carlo simulation is conducted for small sample cases. Empirical power of hypothesis test and coverage probability for confidence interval estimation were presented for simple and multiple legit model respectively. An example were also introduced.

A Logit Model for Repeated Binary Response Data (반복측정의 이가반응 자료에 대한 로짓 모형)

  • Choi, Jae-Sung
    • The Korean Journal of Applied Statistics
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    • v.21 no.2
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    • pp.291-299
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    • 2008
  • This paper discusses model building for repeated binary response data with different time-dependent covariates each occasion. Since repeated measurements data are having correlated structure, weighed least squares(WLS) methodology is applied. Repeated measures designs are usually having different sizes of experimental units like split-plot designs. However repeated measures designs differ from split-plot designs in that the levels of one or more factors cannot be randomly assigned to one or more of the sizes of experimental units in the experiment. In this case, the levels of time cannot be assigned at random to the time intervals. Because of this nonrandom assignment, the errors corresponding to the respective experimental units may have a covariance matrix. So, the estimates of effects included in a suggested logit model are obtained by using covariance structures.

A Generalized Marginal Logit Model for Repeated Polytomous Response Data (반복측정의 다가 반응자료에 대한 일반화된 주변 로짓모형)

  • Choi, Jae-Sung
    • The Korean Journal of Applied Statistics
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    • v.21 no.4
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    • pp.621-630
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    • 2008
  • This paper discusses how to construct a generalized marginal logit model for analyzing repeated polytomous response data when some factors are applied to larger experimental units as treatments and time to a smaller experimental unit as a repeated measures factor. So, two different experimental sizes are considered. Weighted least squares(WLS) methods are used for estimating fixed effects in the suggested model.

A Study on Change of Travel Patterns According to Public Transportation Reform (A Case Study of Gyeongsan City) (대중교통체계 개편에 따른 대중교통 이용자들의 통행패턴 변화에 관한 연구 (경산시를 사례로))

  • Yun, Dae-Sik;Park, Hyeon-Cheol
    • Journal of Korean Society of Transportation
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    • v.28 no.1
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    • pp.51-61
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    • 2010
  • The main objective of this paper is to analyze change of travel patterns according to public transportation reform. The paper uses data collected from Gyeongsan City. So far few researches, especially using before-and-after individual travel survey, have been conducted on analyzing effects of public transportation reform. For this research, some descriptive statistical analyses and statistical hypotheses tests were conducted. Furthermore, some empirical logit models were estimated for analyzing the individual effects of the public transportation reform. Finally, some important foundings, policy implications, and limitations of this research are discussed.