• Journal of Korean Society of Transportation
• /
• v.16 no.4
• /
• pp.127-138
• /
• 1998

본 논문에서는 기존의 교통정보 시스템의 단점을 보완하는 중앙집중형 교통정보 시스템의 구축에 관하여 설명한다. 이 시스템은 중앙의 교통정보센터에서 전자지도 및 교통정보를 관리한다. 따라서, 사용자는 전자지도 및 교통정보 갱신의 필요가 없어지며, 교통정보 수신장치를 통해서 경로 정보를 원하는 시기에 제공받는다. 교통정보 수신장치는, 휴대용 노트북과 개인휴대 통신기기인 Cellular Phone이나 PCS Phone이 결합된 형태로 구현함으로서 대중적으로 널리 보급될 수 있는 교통정보시스템을 구축한다. 본 논문에서는 정확한 교통정보의 생성을 위하여 실시간 교통정보를 저장하는 새로운 교통데이터베이스의 구조를 제시하고 직진,우회전,좌회전,유턴 차량의 흐름을 모두 표현할 수 있는 새로운 교통 네트워크 모델을 제시한다. 많은 수의 노드와 아크로 이루어진 교통 네트워크 내에서, 경로계획 시간이 길어지는 문제 해결 방법으로 전체를 여러 개의 지역으로 나누는 방법을 제시하고, 각 지역 내의 경로계획에는 교통데이터베이스를 참조하는 Dijkstra 알고리즘을 사용한다.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2023.01a
• /
• pp.341-342
• /
• 2023

배터리 기술 고도화 및 기술표준 강화에 따라 완성차 제조사와 배터리 업계간 활발한 협업이이어질 전망이다. 또한 기존 배터리 제조사들이 활발한 증설 및 밸류 체인 확장을 통한 기술가격 경쟁력 격차 유지에 적극적으로 나서고 있어, 향후 시장 주도권 경쟁이 가속화될 것으로 전망된다. 배터리의 온도 상승은 배터리 효율을 낮추는 원인이며, 배터리 온도 제어가 전기자동차 차량의 전체 성능 향상에 중요한 부분이라고 할 수 있다. 본 연구는 실제 Battery Pack 실험 전 열유동해석을 통해 배터리온도 상승추이 및 냉각효율 검증을 진행하는 과정에서 발생하는 과도한 시간 소요를 줄이기 위해 Machine Learning 을 활용하여 검증 효율 및 설계 효율을 높이는데 그 목적이 있으며, CFD를 활용한 배터리 효율 최적화 설계를 하는 기존 모델 대비 30%~50%정도의 성능향상을 예측할 수 있다.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.4
• /
• pp.1269-1278
• /
• 2014

The urban highway, which is a motorway constructed to solve traffic issues, has the characteristic of extremely high damage to life during traffic accidents because the speed of vehicles is higher than typical roadways. In particular, because traffic accidents involving serious injuries hold a very important place among overall traffic accidents, analysis on factors affecting the occurrence of traffic accidents involving serious injuries must be considered with priority when establishing a reduction measure. Therefore, the study built a model that was capable of distinguishing the degree of the factors as part of microscopic analysis for investigating the complex effect of many elements concerning the occurrence of traffic accidents involving serious injuries in urban highways. The results are as follows. First, discriminant model showed a comparatively high level in overall accuracy rates, and, considering the correlation ratio, the models were determined to be valid, as all characteristics of the factors were clearly distinguished. Second, the problems of traffic accidents involving serious injuries on urban highways according to each factor, were clearly drawn out through the discriminant model. Third, the improvement measure for the problems drawn out from the discriminant models were clearly proposed.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.21 no.1
• /
• pp.105-122
• /
• 2022

According to the statistics about the fatal crashes that have occurred on the expressways for the last 5 years, those who died on the shoulders of the road has been as 3 times high as the others who died on the expressways. It suggests that the crashes on the shoulders of the road should be fatal, and that it would be important to prevent the traffic crashes by cracking down on the vehicles intruding the shoulders of the road. Therefore, this study proposed a method to detect a vehicle that violates the shoulder lane by using the Faster R-CNN. The vehicle was detected based on the Faster R-CNN, and an additional reading module was configured to determine whether there was a shoulder violation. For experiments and evaluations, GTAV, a simulation game that can reproduce situations similar to the real world, was used. 1,800 images of training data and 800 evaluation data were processed and generated, and the performance according to the change of the threshold value was measured in ZFNet and VGG16. As a result, the detection rate of ZFNet was 99.2% based on Threshold 0.8 and VGG16 93.9% based on Threshold 0.7, and the average detection speed for each model was 0.0468 seconds for ZFNet and 0.16 seconds for VGG16, so the detection rate of ZFNet was about 7% higher. The speed was also confirmed to be about 3.4 times faster. These results show that even in a relatively uncomplicated network, it is possible to detect a vehicle that violates the shoulder lane at a high speed without pre-processing the input image. It suggests that this algorithm can be used to detect violations of designated lanes if sufficient training datasets based on actual video data are obtained.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.22 no.6
• /
• pp.32-48
• /
• 2023

Autonomous driving technology is shaping the future of personalized travel, encouraging personalized travel, and traffic impact could be influenced by individualized travel behavior during the transition of driving entity from human to machine. In order to evaluate traffic impact, it is necessary to estimate the total number of trips based on an understanding of individual travel characteristics. The Activity-based model(ABM), which allows for the reflection of individual travel characteristics, deals with all travel sequences of an individual. Understanding the relationship between travel and travel must be important for assessing traffic impact using ABM. However, the ABM has a limitation in the data hunger model. It is difficult to adjust in the actual demand forecasting. Therefore, we utilized a Tour-based model that can explain the relationship between travels based on household travel survey data instead. After that, vehicle registration and population data were used for correction. The result showed that, compared to the KTDB one, the traffic generation exhibited a 13% increase in total trips and approximately 9% reduction in working trips, valid within an acceptable margin of error. As a result, it can be used as a generation correction method based on Tour, which can reflect individual travel characteristics, prior to building an activity-based model to predict demand due to the introduction of autonomous vehicles in terms of road operation, which is the ultimate goal of this study.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.20 no.1
• /
• pp.119-130
• /
• 2018

The VE/LCC study on the existing multi-utility tunnel examined the economical feasibility of the collective area through the cost-benefit analysis of the ten major routes of Seoul for the benefit (7 items) and the cost (5 items) through quantitative methods. In this paper, we analyzed the economic efficiency of 61 sectors by adding 3 items (reduced traffic accident, reduced vehicle noise, social-economic loss). The reduced traffic accident item is an improvement of the traffic accident cost that can be saved by the implementation of the project, and the reduced vehicle noise item is an indicator of the amount of noise change caused by the implement of the business. Finally, the social-economic loss items represent the impact on the local economy due to the construction of the multi-utility tunnel. The amounts of the additional items were compared and items added in the open type and tunnel type multi-utility tunnel were analyzed for each analysis. Result on the analysis, it analyzed the items applied to the basic and detail models in the economic evaluation of the multi-utility tunnel design, and makes it possible to evaluate the economic efficiency more efficiently. The economic evaluation of the basic and detailed models including the items presented in this study will be often used in the design of the multi-utility tunnel design.

• Journal of the Korean Society for Railway
• /
• v.18 no.3
• /
• pp.175-185
• /
• 2015

Generally, in the train area, switch tracks have required high reliability because this system is directly associated with derailment. Especially, switch tracks of Maglev vehicles must be moved in terms of the whole geometric characteristics, in which the bogies are encased in the switch track. For this reason, switch track was constructed with steel lighter than concrete girders. But, the steel switch track was weak because of structural vibration as well as structural deformation. Therefore, it is important to predict the levitation stability when a vehicle passes over flexible switch track. The aims of this paper are to develop a coupled dynamic model to describe the relationship between a Maglev vehicle and switch track and to predict the levitation stability. In order to develop the coupled dynamic model, a three dimensional vehicle model was developed based on multibody dynamics; a switch model was made using the modal superposition method. And, the developed model was verified using comparison measured data.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.11
• /
• pp.1309-1315
• /
• 2014

The switch for a maglev vehicle should be designed such that the vehicle safely changes its track without touching the guiderail. In particular, a medium-to-low-speed EMS -type maglev train relies heavily on a U-type electromagnet where it generates levitation force and guidance force simultaneously. Therefore, it is necessary to evaluate the safety of the vehicle whenever it passes the switch, as it lacks active control of the guidance force. Furthermore, when the vehicle passes a segmented switch, which is a group of curves made up of connected lines with a small radius of curvature, it may come into mechanical contact with the guiderail owing to the excessive lateral displacement of the electromagnet. The goal of this study is to analyze the influence of a segmented switch on the safety of major design-related variables for achieving improved running safety. We propose a three-dimensional multibody dynamics model composed of two cars with one body. Using the proposed model, we perform a simulation of the lateral air gap, which is one of the measurements of the running safety of the vehicle when it passes the switch. The analyzed design variables are the length between short span girder, the articulation angle, the length between two centers of a fixed girder at its ends, and the number of girders. On the basis of the effects of the considered design variables, we establish an optimized design of a switch with improved safety.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.4
• /
• pp.297-306
• /
• 2017

The concrete median barrier used currently in South Korea was developed the impact level of SB5-B(270kJ). However, the impact level of SB6(420kJ) should be considered in many placed with the increased accident of heavy vehicles. In order to increase the impact resistance of newly developed concrete median barrier, the computer simulation was conducted before real field test. For the accurate behavior of concrete, the parameter, such as impact vehicle, concrete cover depth and deterioration, was important. In this paper, a parametric study was conducted depending on vehicle curb weight, concrete cover depth and level of deterioration. The impact resistance of concrete median barrier was severely changed depending on vehicle curb weight and concrete cover depth. Furthermore, the impact resistance of concrete median barrier was also decreased due to deterioration of concrete, therefore the repair and rehabilitation should be conducted for damaged concrete depending on deterioration level. Therefore, vehicle curb weight, cover depth of concrete structures and deterioration level of concrete should be carefully considered for conducting analysis of concrete structure to vehicle collision.

• Journal of the Korean Institute of Gas
• /
• v.27 no.3
• /
• pp.123-133
• /
• 2023

Commercial hydrogen fuel cell vehicles are charged by compressing gaseous hydrogen to high pressure and storing it in a storage tank in the vehicle. This process causes the temperature of the gas to rise, to ensure the safety to storage tanks, the temperature is limited. Therefore, a heat transfer model is needed to explain this temperature rise. The heat transfer model includes the convective heat transfer phenomenon, and accurate estimation is required. In this study, the convective heat transfer coefficient in the hydrogen fueling process was calculated and compared using various correlation equations considering physical phenomena. The hydrogen fueling process was classified into the fueling line from the dispenser to the tank inlet and the storage tank in the vehicle, and the convective heat transfer coefficients were estimated according to process parameters such as mass flow rate, diameter, temperature and pressure. As a result, in the case of the inside of the filling line, the convective heat transfer coefficient was about 1000 times larger than that of the inside of the storage tank, and in the case of the outside of the filling line, the convective heat transfer coefficient was about 3 times larger than that of the outside of the storage tank. Finally, as a result of a comprehensive analysis of convective heat transfer coefficients in each process, it was found that outside the storage tank was lowest in the entire hydrogen fueling process, thus dominated the heat transfer phenomenon.