• Title/Summary/Keyword: 음이항 모형

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A Development of Traffic Accident Model by Random Parameter : Focus on Capital Area and Busan 4-legs Signalized Intersections (확률모수를 이용한 교통사고예측모형 개발 -수도권 및 부산광역시 4지 교차로를 대상으로-)

  • Lee, Geun-Hee;Rho, Jeong-Hyun
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.14 no.6
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    • pp.91-99
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    • 2015
  • This study intends to build a traffic accident predictive model considering road geometrics, traffic and enviromental characteristics and identify the relationship of 4-legs intersection accidents in Seoul and Busan metropolitan area. The RPNB(Random Parameter Negative Binomial) model shows improvement over the fixed NB(Negative Binomial) and out of 53 variables, 10 variables (main road number of lane, main road vehicle traffic volume(left), minor road vehicle traffic volume(right), main road drive restriction, minor road sight distance, minor road median strip, minor road speed limit, minor road speed restriction) showed to have significant variables affecting traffic accident occurrences in 4-legs signilized intersections. Also, among 10 significant variables, 2 variables(minor road sight distance, minor road speed restriction) found to be random parameters.

A Development of Traffic Accident Estimation Model by Random Parameter Negative Binomial Model: Focus on Multilane Rural Highway (확률모수를 이용한 교통사고예측모형 개발: 지방부 다차로 도로를 중심으로)

  • Lim, Joon Beom;Lee, Soo Beom;Kim, Joon-Ki;Kim, Jeong Hyun
    • Journal of Korean Society of Transportation
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    • v.32 no.6
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    • pp.662-674
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    • 2014
  • In this study, accident frequency prediction models were constructed by collecting variables such as geometric structures, safety facilities, traffic volume and weather conditions, land use, highway design-satisfaction criteria along 780km (4,372 sections) of 4 lane-highways over 8 areas. As for models, a fixed parameter model and a random parameter model were employed. In the random parameter model, some influences were reversed as the range was expressed based on specific probability in the case of no fixed coefficients. In the fixed parameter model, the influences of independent variables on accident frequency were interpreted by using one coefficient, but in the random parameter model, more various interpretations were took place. In particular, curve radius, securement of shoulder lane, vertical grade design criteria satisfaction showed both positive and negative influence, according to specific probability. This means that there could be a reverse effect depending on the behavioral characteristics of drivers and the characteristics of highway sections. Rather, they influence the increase of accident frequency through the all sections.

A Study on the Estimating Visitor's Economic Value of the Mt. Kumjung by Using Individual Travel Cost Model (개인여행비용법(Individual Travel Cost Model)에 의한 금정산 방문객의 경제적 가치추정)

  • Joo, Soo-Hyun;Lee, Dong-Cheol;Hur, Yoon-Jung
    • Management & Information Systems Review
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    • v.33 no.2
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    • pp.301-315
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    • 2014
  • The purpose of this study is to estimate the economic value of the Kumjung Mountain, using a Individual Travel Cost Model(ITCM). This paper compares Poisson and negative binomial count data models to measure the tourism demands. Interviewers were instructed to interview only individuals. So the sample was taken in 700. A dependent variable that is defined on the non-negative integers and subject to sampling truncation is the result of a truncated count data process. The results suggest that the truncated negative binomial model is improved overdispersion problem and more preferred than the other models in the study. This study emphasizes in particular 'travel cost' that is not only monetary cost but also including opportunity cost of 'travel time'. According to the truncated negative binomial model, estimates the Consumer Surplus(CS) values per trip of about 60,669 Korean won and the total economic value was estimated to be 252,383 Korean won.

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Accident Models of Circular Intersections by Type in Korea (사고유형에 따른 원형교차로 사고모형)

  • Han, Su-San;Kim, Kyung-Hwan;Park, Byung-Ho
    • International Journal of Highway Engineering
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    • v.13 no.3
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    • pp.103-110
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    • 2011
  • This study deals with the traffic accidents by type. The objectives are to analyze the characteristics of 2 accident types, and to develop the models by type. In pursuing the above, this paper gives particular attentions to testing the differences between by type two groups, and developing the models (Poisson and negative binomial regressions) using the data of domestic circular intersections. The main results are as follows. First, the number of accidents in vehicle vehicle was analyzed to account for about 73.41% of total and to be higher than vehicle people. Second, two Poisson models and two negative binomial models which were all statistically significant were developed using vehicle people accidents and vehicle vehicle accidents as dependant variables. Finally, the traffic volume as common variable was selected in the models, and right-turn slip lane, speed hump, the number of driveways, the number of pedestrian crossings as specific variables of the models were selected.

The Selection and Decision in R&D and Patents: A Hurdle Negative Binomial Approach (허들음이항모형을 이용한 기업의 혁신선택과 특허성과의 결정요인에 관한 연구)

  • Park, Jaemin
    • Journal of Korea Technology Innovation Society
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    • v.17 no.3
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    • pp.449-466
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    • 2014
  • There have been various researches on the relationship between a company's R&D investment and the outcome from innovation. However, these studies failed to effectively analyze the decision-making process followed by companies in relation to knowledge production. Especially, in analyzing the patent of companies, the Poisson model has been commonly used, but its limitations have been pointed out. In recent years, many studies have adopted negative binomial models, but they still pose limitations in analyzing the selection process. This paper proposed a hurdle negative binomial model to effectively reflect the company's decision embedded within patent information and conduct an empirical analysis on a survey of businesses' activities. In particular, the study analyzed the selection process of companies in determining the number of patents. As a result of estimation, the presence of over-dispersion was identified. In addition, the Wald-test confirmed that setting up of hurdles was valid, and there was a difference between the results of hurdle models and those of general negative binomial settings.

Developing an Accident Model for Rural Signalized Intersections Using a Random Parameter Negative Binomial Method (RPNB모형을 이용한 지방부 신호교차로 교통사고 모형개발)

  • PARK, Min Ho;LEE, Dongmin
    • Journal of Korean Society of Transportation
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    • v.33 no.6
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    • pp.554-563
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    • 2015
  • This study dealt with developing an accident model for rural signalized intersections with random parameter negative binomial method. The limitation of previous count models(especially, Poisson/Negative Binomial model) is not to explain the integrated variations in terms of time and the distinctive characters a specific point/segment has. This drawback of the traditional count models results in the underestimation of the standard error(t-value inflation) of the derived coefficient and finally affects the low-reliability of the whole model. To solve this problem, this study improves the limitation of traditional count models by suggesting the use of random parameter which takes account of heterogeneity of each point/segment. Through the analyses, it was found that the increase of traffic flow and pedestrian facilities on minor streets had positive effects on the increase of traffic accidents. Left turning lanes and median on major streets reduced the number of accidents. The analysis results show that the random parameter modeling is an effective method for investigating the influence on traffic accident from road geometries. However, this study could not analyze the effects of sequential changes of driving conditions including geometries and safety facilities.

A Study on the Convergence Determinants of Premium Bottled Water Purchase Demand (프리미엄 생수 수요에 대한 융합적 영향요인 분석)

  • Lee, Won-Ok;Kim, Soon-Jung
    • Journal of the Korea Convergence Society
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    • v.6 no.6
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    • pp.221-229
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    • 2015
  • This study aims to identify and analyze the main factors that determine the properties and buying behavior in the premium bottled select and analyze the degree of impact on the relevant variables are premium water demand. When applied to the truncated negative binomial model to derive the study results: The results of estimating the variables that affect the demand for premium mineral water are as follows. Premium bottled water demand of this group my purchases with a choice between buying behavior variables are significantly higher than the relative population. To also do a good ingredient water, it appeared to be on a statistically significant positive effect on the demand for the more groups you purchase a premium bottled water for the purpose of receiving special feeling, just buy purpose is called to drinking water does not significantly affect to be analyzed. Among demographic characteristics it showed that demand for premium bottled water purchases are significantly higher in women than in men, professional / clerical job, such as the military, college graduates were more consumer research as significant in comparison to the relative population. Taste and package design factors of premium bottled mineral water among the select attribute factors are having a significant positive impact on the purchasing demand, local conditions and cost factors have been estimated to be insignificant.

A Study on Marginal Effect of Geometric Structure on Freeway Accident Frequencies (고속도로 교통사고에 대한 기하구조의 영향(한계효과)에 관한 연구)

  • Park, Min Ho
    • Journal of Korean Society of Transportation
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    • v.32 no.1
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    • pp.73-81
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    • 2014
  • This study dealt with the impacts of geometric structure on traffic accidents occurring on the interstates. There are standard values for the case of geometric structure which are recommended in the design guideline/policy; however, in the previous models, geometric variables were adapted as integrated ones as opposed to mixed ones in the real world so that derived models had a weakness to reflect the real. Therefore, using subdivided geometric variables, this study tried to derive the model which reflects the real world. In addition, by calculating elasticity, each variables' effect to the accidents are estimated. Hopefully, this study will help to establish the future guideline/policy of geometrics considering traffic safety.

Testing for Overdispersion in a Bivariate Negative Binomial Distribution Using Bootstrap Method (이변량 음이항 모형에서 붓스트랩 방법을 이용한 과대산포에 대한 검정)

  • Jhun, Myoung-Shic;Jung, Byoung-Cheol
    • The Korean Journal of Applied Statistics
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    • v.21 no.2
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    • pp.341-353
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    • 2008
  • The bootstrap method for the score test statistic is proposed in a bivariate negative binomial distribution. The Monte Carlo study shows that the score test for testing overdispersion underestimates the nominal significance level, while the score test for "intrinsic correlation" overestimates the nominal one. To overcome this problem, we propose a bootstrap method for the score test. We find that bootstrap methods keep the significance level close to the nominal significance level for testing the hypothesis. An empirical example is provided to illustrate the results.

Accident Models of Rotary by Vehicle Type (차량유형별 로터리 사고모형)

  • Han, Su-San;Park, Byeong-Ho
    • Journal of Korean Society of Transportation
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    • v.29 no.6
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    • pp.67-74
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    • 2011
  • This study deals with the traffic accidents data from the Korean rotaries (circular intersections) to verify their characteristics affected by different vehicle types. This paper categorized the data into three groups based on vehicle types, and developed a set of accident models. The paper proposed two ZIP models and one negative binomial model through a statistical analysis for three vehicle types: automobile, truck and van, and others. The differences among those models were then statistically compared.