• Communications for Statistical Applications and Methods
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• 제18권5호
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• pp.571-579
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• 2011

본 연구에서는 두 반응 변수에 서로 다른 산포를 허용하는 새로운 이변량 영과잉 음이항 회귀모형을 제안하고, Deb과 Trivedi (1997)에 나타난 헬스케어 자료를 이용하여 두 반응변수가 갖는 서로 다른 산포도를 무시한 Wang (2003)이 제안한 이변량 영과잉 음이항 회귀모형과의 효율성을 로그우도와 AIC의 관점에서 비교 하였다. 모형적합결과, 본 연구에서 제안한 모형이 모형선택기준 관점에서 기존모형에 비하여 월등히 우수한 결과를 보여주었다.

• 한국도로학회논문집
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• 제17권5호
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• pp.39-46
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• 2015

PURPOSES: The operational characteristics of roundabouts are generally influenced by location as well as traffic volume. The goal of this study is to develop urban and rural roundabout accident models and to discuss safety improvement guidelines based on the model. METHODS : To analyze accidents, count data models are utilized in this study. This study used accident data from 2010 to 2013 for 56 roundabouts collected from the Traffic Accident Analysis System (TASS) of Road Traffic Authority. Poisson and negative binomial regression models were developed for this study using NLOGIT 4.0. RESULTS : The main results are as follows. First, the hypotheses that there are distributional differences in the number of accidents and injuries/fatalities among rural and urban roundabouts were accepted. Second, Poisson and negative binomial regression accident models, which were all statistically significant, were developed. Seven independent variables, which were statistically significant, were adopted. Third, the common variable of models was evaluated to be traffic volume. CONCLUSIONS : This study developed two negative binomial roundabout accident models and suggested some accident reduction strategies. The results are expected to give some implications to the safety improvement of roundabout.

• 기술혁신학회지
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• 제17권3호
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• pp.449-466
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• 2014

그동안 기업의 R&D 투자와 기술혁신 성과의 관계에 관해 여러 연구가 있었다. 하지만 지식생산과정에 수반되는 기업의 의사결정 과정은 효과적으로 분석에 반영되지 못하였다. 특히 기업의 특허성과를 분석함에 있어 포와송모형의 한계에 대응해 최근 연구는 음이항모형을 적용해 극복하고자 했지만 기업의 선택과정을 분석하는데는 한계가 있다. 본 논문은 특허권 정보에 내재된 기업체의 의사결정 과정을 보다 효과적으로 반영하는 실증모형을 제시하고, 사업체조사 결과를 적용해 분석하였다. 특히 기업의 대표적 R&D 성과인 특허에 주목하여 특허 출원건수의 결정과정을 살펴보았다. 분석 결과, 과산포의 존재를 확인할 수 있었고, 허들모형과 일반적인 음이항모형의 결과에 유의한 차이가 있음을 제시하였다. 더불어 Wald-검정을 통해 허들의 설정이 타당하였고, 기업의 특허성과 분석에 있어서 기업의 선택과정을 고려할 필요가 있음을 보였다.

• Communications for Statistical Applications and Methods
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• 제17권6호
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• pp.829-843
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• 2010

To test for the serial dependence in time series of counts data, Jung and Tremayne (2003) evaluated the size and power of several tests under the class of INARMA models based on binomial thinning operations for Poisson marginal distributions. The overdispersion phenomenon(i.e., a variance greater than the expectation) is common in the real world. Overdispersed count data can be modeled by using alternative thinning operations such as random coefficient thinning, iterated thinning, and quasi-binomial thinning. Such thinning operations can lead to time series models of counts with negative binomial or generalized Poisson marginal distributions. This paper examines whether the test statistics used by Jung and Tremayne (2003) on serial dependence in time series of counts data are affected by overdispersion.

• 한국안전학회지
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• 제30권2호
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• pp.70-76
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• 2015

This study deals with the traffic accident of circular intersections. The purpose of the study is to develop the accident models by traffic violation type. In pursuing the above, this study gives particular attention to analyzing various factors that influence traffic accident and developing such the optimal models as Poisson and Negative binomial regression models. The main results are the followings. First, 4 negative binomial models which were statistically significant were developed. This was because the over-dispersion coefficients had a value greater than 1.96. Second, the common variables in these models were not adopted. The specific variables by model were analyzed to be traffic volume, conflicting ratio, number of circulatory lane, width of circulatory lane, number of traffic island by access road, number of reduction facility, feature of central island and crosswalk.

• 한국안전학회지
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• 제29권6호
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• pp.151-157
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• 2014

This study deals with the rear-end collision at roundabouts. The purpose of this study is to develop the accident models of rear-end collision in Korea. In pursuing the above, this study gives particular attention to developing the appropriate models using Poisson, negative binomial model, ZAM, multiple linear and nonlinear regression models, and statistical analysis tools. The main results are as follows. First, the Vuong statistics and overdispersion parameters indicate that ZIP is the most appropriate model among count data models. Second, RMSE, MPB, MAD and correlation coefficient tests show that the multiple nonlinear model is the most suitable to the rear-end collision data. Finally, such the independent variables as traffic volume, ratio of heavy vehicle, number of circulatory roadway lane, number of crosswalk and stop line are adopted in the optimal model.

• Journal of applied mathematics & informatics
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• 제30권1_2호
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• pp.135-145
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• 2012

Traditionally, ERM (Equivalent Random Method) is used to determine number of circuits in an overflow circuit group with rough traffic which has vmr(variance to mean ratio) greater than one. Recently, IPP(Interrupted Poisson Process) approximate method which represents the collective feature of the overflow has been introduced. The negative binomial loss formula can be applied to determine the required number of circuits in the overflow circuit group. In this paper, we deal with the negative binomial loss formula and determination method of number of circuits. We also analyze and compare these three loss formulas.

• 한국안전학회지
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• 제27권6호
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• pp.178-184
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• 2012

This study deals with the traffic accidents by weather condition. The objectives are to comparatively analyze the characteristics, and to develop the models of traffic accidents by weather condition. In pursuing the above, this paper gives particular attentions to testing the differences between two groups, and developing the models(Poisson and negative binomial regression) using the data of domestic circular intersections. The main results are as follows. First, three Poisson models and one negative binomial models which were all statistically significant were developed using the number of accident and EPDO by the clear weather and other as the dependant variables. Second, the differences between two models were comparatively analyzed using the chosen variables. This paper might be expected to give some implications to traffic safety policy-making to reduce and prevent the traffic accidents in circular intersections.

• International journal of advanced smart convergence
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• 제10권4호
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• pp.215-224
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• 2021

The purpose of this study is to estimate the factors that affect college students' drinking needs and spending. An analysis model to estimate the determinants affecting drinking needs was applied with a truncated Poisson model and a truncated negative binomial model. Tests to select more appropriate models of the two types were made using the comparison of log-likelihood function and the over-dispersion test. The analysis result was interpreted by applying the truncated negative binomial model as the truncated Poisson model showed over-dispersion. We also applied the Tobit model to analyze the determinantsthat affect college students' expenditure on drinking. According to the analysis, gender, grade, allowance and parental occupation were the factors influencing statistics, and gender, type of household income, and student religion were the factors influencing expenditure.

• 자원ㆍ환경경제연구
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• 제21권4호
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• pp.981-998
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• 2012

이 논문에서는 영산강 하구 방문객을 대상으로 하여 자연휴양지의 수요함수를 추정하여 방문 편익을 도출하기 위해 카운트 자료 모형(count data model)을 적용하였다. 여행지 방문객 자료의 속성을 고려할 때, 포와송 모형의 경우 평균과 분산이 동일하다는 제약적 가정에 의한 과도분산(overdispersion) 속성의 왜곡과 더불어 자료의 1에서 절단 속성을 고려하지 않는 경우의 왜곡이 문제가 된다. 실증 분석 결과에 따르면 방문객 자료의 속성은 반영하는 절단 음이항(truncated negative binomial) 모형이 고려한 모형 중에서 최적이고, 그 모형에 의해 도출된 영산강 하구 1회 방문 편익(즉, 소비자 잉여)는 전라권 거주자들의 경우 89,350원이며, 비전라권 거주자의 경우는 432,526원으로 전라권 거주자의 4.8배 수준이었다. 또한 과도분산의 속성을 반영하지 못하는 포와송 모형으로부터 추정된 영산강 하구의 방문 편익(소비자 잉여)은 과소평가되며, 절단의 속성을 고려하지 못하는 경우의 모형으로부터 추정된 영산강 하구의 방문 편익은 과대평가되는 경향도 확인할 수 있었다. 그러므로 단일 휴양지 방문객에 대한 자료로부터 여행수요 함수 및 방문 편익을 추정하기 위해서는 절단 음이항 회귀모형이 적용되어야 한다.