• Journal of Environmental Impact Assessment
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• v.15 no.1
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• pp.23-33
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• 2006

The factor of air pollution in a large industrial city is not only manufactories but also, activities related to trucks. Sihwa National Industrial Complex is located in Siheung City; due to the industries, more diverse activities related to trucks occur in Siheung City than other cities. In particular, the new residential area in Siheung City is close to the industrial complex; so, the damage of this residential area is expected that it would be more serious and vulnerable than other areas. The aim of this study is to analyze influence of the air pollution by a truck in Siheung City. ISCST3 Model and Arc View program were used for this study and Siheung City was divided into 1,000 meter by 1,000 meter grid to analyze. Furthermore, this study suggested two reduction controls of air pollution in Siheung City, and analyzed the results from these reduction managements. The results of the present condition showed that residences located in north of Sihwa Industrial Complex are influenced by air pollution material. Furthermore, air pollution by trucks has affected on the residents which is near the road in Siheung City. Therefore, this study suggested two reduction controls by the Traffic System Management. The first alternative plan is setting the truck traffic limitation zone in the road that is located in south of resident areas and many trucks traffic. Next, the second alternative plan is setting freight truck way on the most traffic road to enter the industrial complex. The reduction effect of the first alternative is good on the residential area. And, the second alternate about freight truck way is divided passenger cars into trucks. Therefore, there are increase of average speed and decrease of average concentration, and spatial reduction effects found in wide areas.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1178-1185
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• 2010

Recently, high speed of container freight cars is causing fatigue damage of wheel. Sudden failure accidents cause a lot of physical and human damages. Therefore, damage analysis for wheel prevents failure accident of container freight car. Wheel receives mechanical and thermal loads at the same time while rolling stocks are run. The mechanical loads applied to wheel are classified by the horizontal load from contact of wheel and rail in curve line section and by the vertical force from rolling stocks weight. Also, braking and deceleration of rolling stocks cause repeated thermal load by wheel tread braking. Specially, braking of rolling stocks is frictional braking method that brake shoe is contacted in wheel tread by high breaking pressure. Frictional heat energy occurs on the contact surface between wheel tread and brake shoe. This braking converts kinetic energy of rolling stocks into heat energy by friction. This raises temperature rapidly and generates thermal loads in wheel and brake shoe. There mechanical and thermal loads generate crack and residual stress in wheel. Wetenkamp estimated temperature distribution of brake shoe experimentally. Donzella proposed fatigue life using thermal stress and residual stress. However, the load applied to wheel in aforementioned most researches considered thermal load and mechanical vertical load. Exact horizontal load is not considered as the load applied to wheel. Therefore, above-mentioned loading methods could not be applied to estimate actual stress applied to wheel. Therefore, this study proposed safety estimation on wheel of freight car using heat-structural coupled analysis on the basis of loading condition and stress intensity factor.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.361-364
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• 2005

Some bogie frames manufactured in 1999, 2000 year have the fatal problem. Three or four years later, the cracked end beam among them have discovered in 2002, 2003 year. The crack situation of the end beam have a bad effect on brake system. In that case, the cars would be in danger of derailment. To improve the end beam, a research of covering the whole field of welded type bogie frame was started. Main line real tests were performed at Young-Dong line. The stress of main positions for bogie frame was measured. Also up-down direction and left-right direction vibration acceleration of the bogie frame were measured. At this time the tests were performed for the three types bogie. The test result concludes that the crack cause of the end beam is not brake load but vibration at running mainly. It is estimated that the life of the improved car which end beam reinforced is safe within the car permitted life(25 years). The improvement methods of the end beam are presented by construction modification, parts modification. The integrity evaluation is inspected by analysis the real line test results, the improvement methods of the end beam.

• International Journal of Highway Engineering
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• v.18 no.5
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• pp.95-103
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• 2016

PURPOSES : Permitted left turn is a turning maneuver in which a vehicle turns left using a gap between oncoming vehicles, called gap acceptance, and it enables for more efficient traffic operation at intersections. In Korea, the permitted left turn has not been a common maneuver at signalized or un-signalized intersections. However, many experts and the Police Agency tried to apply this effective turning maneuver at intersections in Korea since 2010. Though the investigation of gap acceptance is significantly important in understanding a driver's behavior at intersections, there have not been many studies about this topic, specifically a study to develop probability models of gap acceptance behavior. METHODS : In this study, the probability model of gap acceptance behavior for a permitted left turn was developed based on observational field studies. To develop the model, seven variables were analyzed including gap, waiting time, traffic volume, conflict-flow vehicle type, left-turning vehicle type, the number of lane, and time. RESULTS : In the final model, gap and left-turning vehicle type were found to be significant influencing factors. CONCLUSIONS : Through this model development, it was concluded that as the gap size increased, the probability of gap acceptance was higher. Moreover, when a left-turning vehicle was a passenger car, the probability of gap acceptance was higher than compared to large size buses or freight cars.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.3
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• pp.53-59
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• 2021

In vibration-free vehicles such as limousine buses, the vibration is minimized by installing an air spring instead of the leaf spring used in the existing freight cars to prevent the damage to the loaded cargo from shocks generated during movement. In the existing vehicles, steel structures support the air spring system. This study was aimed at replacing the steel structures used in the Z-spring by carbon fiber and glass fiber reinforced plastics. In addition, the mechanical properties (elastic modulus, tensile strength, and shear strength) of carbon fiber and glass fiber prepreg were derived using specimens molded with the corresponding prepreg. The final goal was to develop a material lighter than the conventional steel material but with enhanced mechanical properties. Although the CF prepreg exhibited excellent mechanical properties, the production cost was extremely high. To overcome this limitation, hybrid composites with GF prepreg were examined, which are expected to be promising future materials.

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.5
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• pp.273-280
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• 2022

Along with the advancement of deep learning technology, securing high-quality dataset for verification of developed technology is emerging as an important issue, and developing robust deep learning models to the domestic road environment is focused by many research groups. Especially, unlike expressways and automobile-only roads, in the complex city driving environment, various dynamic objects such as motorbikes, electric kickboards, large buses/truck, freight cars, pedestrians, and traffic lights are mixed in city road. In this paper, we built our dataset through multi camera-based processing (collection, refinement, and annotation) including the various objects in the city road and estimated quality and validity of our dataset by using YOLO-based model in object detection. Then, quantitative evaluation of our dataset is performed by comparing with the public dataset and qualitative evaluation of it is performed by comparing with experiment results using open platform. We generated our 2D dataset based on annotation rules of KITTI/COCO dataset, and compared the performance with the public dataset using the evaluation rules of KITTI/COCO dataset. As a result of comparison with public dataset, our dataset shows about 3 to 53% higher performance and thus the effectiveness of our dataset was validated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.843-850
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• 2020

The purpose of this study is to evaluate the structural risk and weakness of a railway tank car through nonlinear collision analysis according to overseas collision safety standards. The goal is to propose a crash safety design guideline for railway tank cars for transporting dangerous goods in Korea. We analyzed the buffer impact test procedure of railway freight cars prescribed in EN 12663-2 and the tank puncture test criteria prescribed in 49CFR179. A nonlinear finite element model according to each standard was modeled using LS-DYNA, a commercial finite element analysis solver. As a result of the buffing impact test simulation, it was predicted that plastic deformation would not occur at a collision speed of 6 km/h or less. However, plastic deformation was detected at the rear of the center sill and at the tank center supporting the structure at a collision speed of 8 km/h or more. As a result of a head-on test simulation of tank puncture, the outer tank shell was destroyed at the corner of the tank head when 4% of the kinetic energy of the impacter was absorbed. The tank shell was destroyed in the area of contact with the impacter in the test mode analysis of tank shell puncture when the kinetic energy of the moving vehicle was reduced by 30%. Therefore, the simulation results of the puncture test show that fracture at the tank shell and leakage of the internal material is expected. Consequently, protection and structural design reinforcement are required on railway tank cars in Korea.

• Journal of the Korean Society for Railway
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• v.15 no.5
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• pp.517-523
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• 2012

Double Stack Train(DST) is being used variously around USA and Canada. The greatest advantage of the DST is mass transportation without extending the length of freight train and number of cars. So the DST system can be a kind of innovative train to increase the competitiveness of rail logistic business. As the domestic rail logistic increase, for enhancement of environment friendly green transportation amount, the DST needs more for efficiency. In this study, as the alternative way to introduce the DST to the Kyungbu Line, it's investigated the extensibility of rail freight with the relation of rail fare discount and examined the necessity of pilot business to the Kyungjeon Line which was expected comparatively lower cost. If the DST system is introduced to the Kyungjeon Line, the cost of mass transportation can be much lower and then the comparativeness of rail transportation will be increased, therefore logistic companies can have some margin additionally. In the result of survey to the related companies, if rail transportation fare is 37.7 % cheaper than current road transportation fare, the modal shift can be transferred by maximum 100%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.845-853
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• 2017

The main reason for urban traffic problems is the increasing in the use of private cars. In order to solve this problem, strong traffic demand management policies such as the collection of congestion tolls and the crackdown on freight vehicles are emerging. Now, however, it is necessary to seek ways for users to make changes in traffic behavior through direct communication between public agencies and passenger car users. As a technique to make this possible, mobility management, which aims to use rational passenger cars by inducing behavior change through individual consciousness change, has recently been proved to be effective in overseas. Therefore, this study concluded that the introduction of MM, which emphasizes individual voluntary behavior change, is necessary at present. In order to investigate the ways of inducing voluntary changes in traffic behavior of passenger car users, a questionnaire survey was conducted on traffic experts and the priorities of voluntary traffic behavior change measures were calculated using AHP. As a result of the analysis, it was shown that "to actively appeal to change the traffic behavior by using the mass media" was the top priority. The next priority were in order of company education for the change of traffic behavior, education for the school, and small-scale workshops.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.403-411
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• 2020

This paper discusses the main findings of the development of the twin-hull Car ferry for island freight and passenger transport. The final model had a 19 m wide beam to create enough space for cars on the deck area and thus, enhance the economic feasibility in the market. The vessel had a V-shape with a bulbous bow to minimize the wave-making resistance and the hydrodynamic performance of the ship was verified through computational fluid dynamics. Multi-objective optimization problems of Pareto simulated annealing were used to achieve a weight reduction of approximately 3.9 % and reduce the manufacturing cost. The main results obtained in this study are expected to be useful to engineers and professionals in related industries interested in research on twin catamaran.