• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.5
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• pp.155-163
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• 2006

Car seat is one the most important element to make comfortable drivability. It can absorb the impact or vibration during driving state. In addition to those factors, it is needed to have enough strength for passenger safety. From energy efficiency and environmental point of view lighter passenger car seat frame becomes hot issue in the auto industry. In this paper, weight optimization methodology is investigated for commercial car seat frame using CAE. Optimized designs for seat frame are developed using commercially available finite element code(ANSYS) and design of experiment method. At first, car seat frame is modelled using 3-D computer aided design tool(CATIA) and simplified for finite element modelling. Finite element analysis is carried out for the case of FMVSS 202 Head Restraint test to check the strength of the original seat frame. Two base brackets are selected as optimized elements that are the heaviest parts in the seat frame. After finite element analysis for the brackets with similar load condition to the previous test optimization technique is applied for 10% to 50% weight reduction. Design of experiment is utilized to obtain optimization design for the bracket based on the modified 50% weight reduction model in which outer shape of the bracket is conserved. Weight optimization models result in the decrease of the strength in spite of weight reduction. The more design points should be considered to get better optimized model. The more advanced optimization technique may be utilized for more parts of the seat frame to increase whole seat frame characteristics in the future.

• Journal of recreation and landscape
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• v.12 no.4
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• pp.1-10
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• 2018

This study is about the investigation of the walking environment of the First Experimental Elementary School in Shapingba District of Chongqing City and the Zaozilanya Elementary School in Yuzhong District and the analysis of the pedestrian's consciousness. The improvement plan is obtained by comparing and analyzing the walking environment around the school. The survey results are as follows. According to the survey results of the walking environment around the school, the sidewalks of the two schools are relatively narrow, and there are more pedestrians crossing the road. There is a phenomenon of parking in both schools. The phenomenon of parking in Zaozilanya Elementary School is even more serious. In investigating the most important elements of the school's pedestrian environment, the setting of the signpost, the setting of the crosswalk and signal lights, the setting of the fence, the setting of the vehicle's deceleration facilities, and the control of the school gate are all necessary. Therefore, in order to create a safe and comfortable improvement plan for the surrounding environment of the school, first of all, in the improvement of the facilities around the school, the setting of the fence, the setting of the speed bump, the improvement of the crosswalk and the signal light. Second, in terms of restrictions, the scope of protection around the school needs to be expanded, and restrictions on parking and restrictions on vehicle traffic need to be implemented. Third, in terms of education and publicity, it is not only necessary to provide safety guidance for students to go to school, but also to provide drivers with driving safety education and publicity.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.6
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• pp.21-34
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• 2011

VANET offers variety of services to allow safe and comfortable driving through V2V and V2I communications in transportation systems. To use these services, safe and reliable V2V and V2I communications must be guaranteed. In this regards, many RSU-based studies have been carried out to meet certain issues such as: efficiency of frequent communication between RSU and vehicles, security of stored information in RSU, and invasion on vehicle's privacy. In this paper, a scheme is proposed to reduce the dependency on RSU and to enhance the vehicle privacy by using signature-based authentication protocol. The proposed protocol is more efficient than existing protocol with group signature, and satisfies all the requirements of VANET.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.3
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• pp.40-46
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• 2021

An automatic transmission of automobiles enables comfortable driving experience with lower transmission shifting jerks. However, the assembly structure is more complicated and requires additional components with lower efficiency than the manual transmission system. Extensive research has been conducted to improve the overall transmission efficiency by optimizing each component of the automatic transmission assembly. This study focuses on enhancing the friction torque of double angular contact ball bearings used in automatic transmission. The friction torque of the bearing varies with the operating conditions such as the operational load and rotating speed. Since reducing the friction torque of the bearing tends to deteriorate the durability of the bearing, it is necessary to design the bearing having a minimum required friction torque by determining the durability life of an automatic transmission assembly, In this study, the theoretical life and friction torque of conventional and newly-developed bearings are calculated. The difference in the friction torque between the new and existing bearings are also evaluated.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.4
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• pp.95-105
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• 2021

Road surface damage detection is essential for a comfortable driving environment and the prevention of safety accidents. Road management institutes are using automated technology-based inspection equipment and systems. As one of these automation technologies, a sensor to detect road surface damage plays an important role. For this purpose, several studies on sensors using deep learning have been conducted in recent years. Road images and label images are needed to develop such deep learning algorithms. On the other hand, considerable time and labor will be needed to secure label images. In this paper, the adversarial learning method, one of the semi-supervised learning techniques, was proposed to solve this problem. For its implementation, a lightweight deep neural network model was trained using 5,327 road images and 1,327 label images. After experimenting with 400 road images, a model with a mean intersection over a union of 80.54% and an F1 score of 77.85% was developed. Through this, a technology that can improve recognition performance by adding only road images was developed to learning without label images and is expected to be used as a technology for road surface management in the future.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.37-46
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• 2021

Government agencies, such as police and local governments, strive to prevent traffic hazards and create a comfortable road environment by pormoting transportation and road facilities. To this end, roads and transportation facilities are enhanced and adjusted, and improvement projects in areas with frequent traffic accidents are carried out. Usually, improvement projects in areas with frequent traffic accidents vary by projects and region. Moreover, these projects are carried out under the supervision of a person in charge and related parties. Hence, civil complaints and subjectivity are reflected in deriving priorities for the improvement projects, limiting the efficiency of the project. To this end, a study was conducted to estimate the direction of improvement of the project target site. This study comprehensively considered road, traffic, and accident conditions of representative projects with high effectiveness in handling traffic accidents. The results of the study state that the accuracy of estimating the improvement project was around 88%. In addition, the study found that there was a strong relationship between traffic volume, accident rate, and accident severity in estimating the improvement direction.