• Journal of Korean Society of Transportation
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• v.26 no.2
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• pp.167-176
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• 2008

Although a rate of car accident death is on the decrease, internal rate of median encroachment accident is still high. In order to reduce the median encroachment accident, government use median barriers but there are no exact criteria of them. Particularly, current impulse measurement method has adopted the uniformly operating speed and encroachment angle. At reality, however, there are various conditions depends on driver's characters. In that reason, this study calculates reasonable impulse quantity through encroachment angle and operating speed. It will be necessary to prevent overuse treasury and car accidents.

• Journal of Korean Society of Transportation
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• v.15 no.1
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• pp.129-156
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• 1997

8차로 고속도로에서 중앙분리대와 길 어깨에 의해 측방 여유폭이 제공되는 외측차 로(1.4차로)와 측방 여유폭이 제공되지 않는 내측차로 (2.3차로)에서 나타나는 운전자의 횡 방향 주행특성을 4개 지점에서 비디오 촬영하여 분석한 결과는 다음과 같다. (1) 차량의 횡 방향 주행궤적은 차로의 중심으로부터 주행방향의 좌측으로 이격된 주행 행태를 보이고 있 으며 이는 운전석의 위치에 의한 영향으로 판단된다. (2) 차량의 병행 주행시 외측 차로의 중심 이격 거리는 평균 0.38m이고 내측차로의 중심 이격 거리는 평균 0.34m로 나타났으며 T-test 겨로가 내측 차로와 외측 차로의 주행 이격 거리는 신뢰도 95%에서 상이한 것으로 나타났다. (3) 외측 차로의 주행궤적간 이격 거리는 평균 3.90m이고 내측 차로의 주행궤적 간 이격 거리는 평균 3.54m로서 내측 차로의 주행궤적간 이격 거리는 외측 차로의 주행궤 적간 이격 거리보다 0.36m 작다. 특히 내측 차로의 주행궤적간 이격 거리는 내측 차로간 차로 중심간 간격인 3.6m 보다 0.1m 작은 것으로 나타났다. (4) 내측차로 확장 대안으로 기존 도로폭 유지안 (3.5m, 3.7m, 3.5m)과 기존 도로폭 확장안 (3.6m, 3.7m, 3.7m, 3.6m)을 고려할 수 있으며 두 대안의 비교·분석결과 경제적 영향을 고려할 때 기존 도로폭 유지안이 우수한 것으로 분석되었다.

• Restorative Dentistry and Endodontics
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• v.35 no.4
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• pp.302-305
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• 2010

Mandibular premolars show a wide variety of root canal anatomy. Especially, the occurrence of three canals with three separate foramina in mandibular second premolars is very rare. This case report describes the root canal treatment of an unusual morphological configuration of the root canal system and supplements previous reports of the existence of such configuration in mandibular second premolar.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.01a
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• pp.301-302
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• 2022

최근 지상 통로에 차량 통행 공간과 보행자 통행 공간이 분리되어있지 않은 공원형 아파트가 증가하고 있다. 이로 인해 택배 차량의 아파트 단지 안으로 진입을 통제하는 아파트가 늘어나고 있다. 현재는 이러한 상황에서 택배기사들이 직접 손수레를 끌고 아파트 안으로 들어가거나, 수령인이 직접 아파트 입구에서 택배를 수령하는 방법으로 문제를 해결 해 왔다. 본 논문은 이러한 불편함을 개선하기 위해 아파트 입구에서 집 앞까지 인공지능 기술과 카메라, 라이다센서를 이용하여 자율주행으로 택배를 운반 해줄 수 있는 '자율주행 택배 운반 로봇' 기술을 제안한다. 기존의 사람이 직접 택배를 집 앞까지 운반하는 방식이 아닌 자율주행 로봇을 이용한 방식으로 택배기사들의 과로로 인한 사고를 예방하고, 아파트 입주민들의 불편도 줄어들 것이다.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.325-328
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• 2019

자율주행 자동차는 운전자가 개입하지 않고 차량에 부착된 다양한 센서를 통해 얻은 데이터를 기반으로 차량을 스스로 제어하며 설정한 목적지까지 주행한다. 본 논문에서는 단일 카메라와 영상을 사용한 차선 검출하고 추적하는 방법을 제안한다. 영상의 하단 부분만 분리하여 차선을 검출하기 위하여 외곽선 검출 과정을 거친 후 허프 변환을 통해 양 차선의 중심을 구한다. 이 값을 바탕으로 PID 제어로 차량의 차선을 유지한다. 모형 차량과 모형 트랙에서 차선 인식 후 차선을 추적하여 주행하는 동작을 시험하였다. PID 제어를 위헌 적정 각 항의 값을 구하였다. 시험 결과 차선 검출 알고리즘은 성공적으로 동작함을 확인할 수 있었다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.739-748
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• 2013

In this study, analytical works for the induced winds due to traveling vehicles on highway have been conducted by Computation Fluid Dynamics (CFD). The traveling condition was considered in two cases: (a) single direction and (b) bi-direction. The analysis was focused on the effects of the induced winds on the upper part of a median strip while the aerodynamic characteristics of the vehicles were directly analyzed in the previous studies. From the analysis results, it has been found that the maximum magnitude of the induced winds was 2.2 m/s when the vehicles travel with the speed of 50 km/h. Additionally, 4.0 m/s and 5.3 m/s were obtained with the speed of 90 km/h and 120 km/h, respectively. Especially, the induced winds was generated about 84% of the vehicle speed at 1.0 m above from the median strip when the vehicles travel with the speed of 120 km/h. The induced winds was maintained during the very short period while the traveling. conclusively, it is noted that the wind power generation can be possible by using the small-sized wind power generators installed on median strips throughout the analytical results in this study.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.147-161
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• 2021

The purpose of this study was to investigate the psychological state and driving safety of drivers driving around the truck platoon driving. Using the driving simulator, the experimental environment was constructed with the situation of changing lanes to the platoon and driving within the platoon. We tried to qualitatively and quantitatively analyze the driver's psychological state and driving safety through simulation driving experiments. As a result, in the case of the older driver group, there were many cases where they judged themselves to be driving safely, even though they were driving dangerously in the actual lane change to the platoon or driving within the platoon. In particular, this group showed that the narrower the distance between vehicles, the greater the misrecognition. The results of this study are expected to be useful in deriving the optimum interval when the interval between platooning of trucks needs to be temporarily extended.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.5
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• pp.182-199
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• 2023

Since 2021, government departments have been promoting Automated Driving Technology Development and Innovation Project as national research and development(R&D) project. The automated vehicles and service technologies developed as part of these projects are planned to be subsequently provided to the public at the selected Living Lab City. Therefore, it is important to determine a spatial area and operation section that enables safe and stable automated driving, depending on the purpose and characteristics of the target service. In this study, the static Operational Design Domain(ODD) elements for Level 4 automated driving services were reclassified by reviewing previously published papers and related literature surveys and investigating field data. Spatial analysis techniques were used to consider the reclassified ODD elements for level 4 in the real area of level 3 automated driving services because it is important to reflect the spatial factors affecting safety related to real automated driving technologies and services. Consequently, a total of six driving mode changes(disengagement) were derived through spatial information analysis techniques, and the factors affecting the safety of automated driving were crosswalk, traffic light, intersection, bicycle road, pocket lane, caution sign, and median strip. This spatial factor analysis method is expected to be useful for determining special areas for the automated driving service.

• Journal of Korean Society of Transportation
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• v.26 no.3
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• pp.187-197
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• 2008

While driving a highway, A driver gets lots of information through geometrical structure, traffic situation, signs on the road. He gets most of the information by visual sense. Acceleration or deceleration and driving direction depend on sight distance. Therefore, it's essential to secure a driver's sight distance for a safe drive. However, design guides of geometrical structure and sight distance suggest respective standards of horizontal and vertical alignment. They do not indicate quantitative standard of combined alignment. Currently, element separated on a two-dimensional projected plane are available, but they do not guarantee safe and pleasant design. I will use the existent model analysing three-dimensional sight distance through mathematical calculation and sort a variety of geometrical structure element and type. In these researches, we will look at how much three-dimensional sight distance is overestimated or underestimated compared to two-dimensional. I will develop a program which predicts traffic velocity on the curvature of two-lane provincial road. stopped sight distance and three-dimensional sight distance will be compared at a predicted drive velocity. I will suggest the way to evaluate road consistency.

• Journal of Korean Society of Forest Science
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• v.104 no.1
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• pp.98-103
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• 2015

This study was conducted to analyze the running stability of a semi-crawler type mini-forwarder. The running stability analysis was performed by using a dynamic analysis program, RecurDyn. Physical properties of the semi-crawler type mini-forwarder was performed by using 3D CAD modeler, AutoCAD 3D. As a result from the computer simulation of stationary sideways overturning, it was found that the semi-crawler type mini-forwarder runs safely on a road with a slope not bigger than $20^{\circ}$ regardless whether it is empty or loaded, but in case of a road with a slope bigger than $20^{\circ}$, it is assumed that it is difficult for the car to run safely due to some dangers. In addition, it was found that the critical slope of its sideways overturning gets much smaller when empty since the location of its gravity center is elevated and much higher when it is loaded. As a result from the computer simulation of its hill-climbing ability, since the running speed is unstable in case of a road with a vertical slope not smaller than $28^{\circ}$, it is assumed that it is safe to drive it on a road with a slope not bigger than $28^{\circ}$. Taking a look at the result from an analysis of the running safety when it passes an obstacle, it was observed that a front tire comes off the ground when the running speed of the car is 5 and 4 km per hour respectively when it is empty and loaded while the gravity center of the front tire is watched. When taking a look at the changes in the location of the gravity center of the rear wheel crawler shaft, it was not found that the shaft comes off the ground at the test speeds both when it is empty and loaded.