PURPOSES : The primary objective of this study is to analyze the relationship between the factors that affect traffic incident duration in the mainline, tunnel, and ramp segments of an expressway. In addition, this study derived the most suitable statistical prediction model based on various incident duration distributions. METHODS : South Korean expressway crash data for 11 years, from 2011 to 2021, were analyzed. The incident durations on the mainline, tunnel, and ramp segments were selected using the accelerated failure time model, which is a parametric survival analysis approach. RESULTS : The mainline segment showed that the incident duration increased during accidents, including guard pipe collisions, multivehicle collisions, and snowfall. In particular, collisions in a tunnel with shoulder facilities increase the incident duration, while decreasing the time in the ramp segment. CONCLUSIONS : The incident duration model for each segment type yielded the most accurate results when applying a log-logistic distribution.

PURPOSES : The primary purpose of this study is to establish a crash probability model based on a statistical method that explains the relationship between regressor and explanatory variables using both fixed and random effects to control the heterogeneous characteristics of the observed data. In addition, an attempt was made to discover the leading cause of crashes by vehicle type, including passenger car, bus, truck, and trailer. METHODS : The levels of each route and day of the week are grouped using raw expressway crash data for 10 years from 2012 to 2021, and a multilevel mixed-effect logit model is constructed for each vehicle type assuming that the error terms are derived from the hierarchical structure of the group to which they belong. RESULTS : Speeding and obstacles on the road are significant factors that increase the probability of passenger car crashes, and bus crashes have a high rate at toll gates on weekdays. CONCLUSIONS : The multilevel mixed-effect logit model derived in the study has higher accuracy than the general logit model, confirming that mixed-effect analysis is plausible.

기존의 유기계 자외선차단제는 피부투과 및 자극으로 인한 안전성의 문제가 제기되었으며, 무기계 자외선차단제는 나노화에 따른 안전성 문제가 제기되고 있다. 이로 인하여, 최근의 자외선차단제 연구는 유효성뿐만 아니라 안전성이 우수한 다양한 형태의 자외선차단제가 연구되고 있으며, 그 중의 하나가 유기-무기 결합구조의 자외선차단제에 관한 연구이다. 본 연구진은 가교된 고분자 입자 타입의 신규 자외선차단제로서 메톡시신나미도프로필실세스퀴옥산의 제조, 물성 및 유효성 평가에 대하여 보고한 바가 있다. 본 연구는 신규 자외선차단제인 메톡시신나미도프로필실세스퀴옥산의 랫드에 대한 배·태자 발생독성 연구에 관한 것으로서, 이러한 평가는 본 시험물질이 임상에서 임신 전·후에 노출 되었을 경우 불임 및 배ㆍ태아의 이상에 대한 구체적인 정보를 제공해줄 것으로 기대된다.