• Title/Summary/Keyword: 포아송 희귀모형

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Rear-end Accident Models of Rural Area Signalized Intersections in the Cases of Cheongju and Cheongwon (청주.청원 지방부 신호교차로의 후미추돌 사고모형)

  • Park, Byoung-Ho;In, Byung-Chul
    • International Journal of Highway Engineering
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    • v.11 no.2
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    • pp.151-158
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    • 2009
  • This study deals with the rear-end collisions in the rural aiea. The objectives of this study are 1) to analyze the characteristics of rear-end accidents of signalized intersections, and 2) to develop the accident models for Cheongju-Cheongwon. In pursing the above, this study gives the particular attentions to comparing the characters of urban and rural area. In this study, the dependent variables are the number of accidents and value of EPDO(equivalent property damage only), and independent variables are the traffic volumes and geometric elements. The main results analyzed are the followings. First, the statistical analyses show that the Poisson accident model using the number of accident as a dependant variable are statistically significant and the negative binomial accident model using the value of EPDO are statistically significant. Second, the independent variables of Poisson model are analyzed to be the ratio of high-occupancy vehicles, total traffic volume and the sum of exit/entry, and those of negative binomial regression are the main road width, total traffic volume and the ratio of high-occupancy vehicles. Finally, the specific independent variables to the rural area are the main road width, the ratio of high occupancy vehicle, and the sum exit/entry.

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Analysis of Failutr Count Data Based on NHPP Models (NHPP모형에 기초한 고장 수 자료의 분석)

  • Kim, Seong-Hui;Jeong, Hyang-Suk;Kim, Yeong-Sun;Park, Jung-Yang
    • The Transactions of the Korea Information Processing Society
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    • v.4 no.2
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    • pp.395-400
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    • 1997
  • An important quality characteristic of a software reliability.Software reliablilty growh models prvied the tools to evluate and moniter the reliabolty growth behavior of the sofwate during the testing phase Therefore failure data collected during the testing phase should be continmuosly analyzed on the basis of some selected software reliability growth models.For the cases where nonhomogeneous Poisson proxess models are the candiate models,we suggest Poisson regression model, which expresses the relationship between the expeted and actual failures counts in disjonint time intervals,for analyzing the failure count data.The weighted lest squares method is then used to-estimate the paramethers in the parameters in the model:The resulting estimators are equivalent to the maximum likelihood estimators. The method is illustrated by analyzing the failutr count data gathered from a large- scale switchong system.

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