• Journal of the Korean Society for Railway
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• v.17 no.5
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• pp.381-389
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• 2014

This research focuses on the current trend of 'Sharing Transportation' to clarify the regional factors having a decisive effect on the use of Car Sharing. To accomplish this, the current research is built a Database of the regional characteristics of Car Sharing spots based on railway stations in Seoul and performed an analysis of the primary regional factors affecting Car Sharing usage. As a result, we found conclusive factors affecting the use of Car Sharing. This research can be utilized for establishing strategies and effective measures to support the use of Car Sharing and sustainable development with respect to issues of motorization.

• Journal of the Korean Society for Railway
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• v.16 no.3
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• pp.183-188
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• 2013

The purpose of maintaining rolling stock is to perform train service without failure during operation. It is not possible to prevent failure, however, by using periodic preventive maintenance methods, because new rolling stock is made from many electric components and requires the application of IT skills. RAMS (Reliability, Availability, Maintainability, Safety) methods have consequently been applied to new manufactured rolling stock in KORAIL since implementation of the KTX. With this approach it is possible to verify the reliability at the operating stage, and RCM (Reliability Centered Maintenance) methods for maintenance have been applied to manufactured rolling stock since the beginning of KTX service. A RCRM (Reliability Centered Rolling-stocks Maintenance) system suitable for the characteristics of rolling stock and operational factors is introduced in this paper.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.243-248
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• 2018

The abnormally high temperature of the train part is related to train accidents and monitoring is important for safe operation of trains. In case of KTX an abnormality detecting device that detects the abnormality of the axle and scans the urban railway is installed on the railroad and when there is an abnormal heat generation, a system for automatically informing the control center is installed. The IR sensors module used in this system are depend on quick response. we have conducted a study on the fast response test method through the production of experimental equipments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.1
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• pp.199-206
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• 2019

Recently, an expansion of safety facilities has been widely applied to effectively manage the safety of train operation due to increase of the high-speed section of the general railway and the introduction of high-speed train. Accordingly, performance improvement, upgrading and high reliability of existing safety devices are required. the dragging detector, one of the safety devices, is an analogue system that consists of closed circuit with an electric current flows and operates when the closed circuit is opened by the impact of the dragging object. Such method has unreasonable problem that should be replaced after being detected. It is need to replace with an automatic return type dragging detector which is easy to maintain. In addition, it is necessary to develop a dragging detector that applicable to general railway and urban railway including high-speed railway, in accordance with the speeding up and densification of trains, although it is currently applied only to high-speed railway. In this paper, we propose an automatic return type dragging detector which has versatility and excellent maintainability with digital sensor and real time monitoring.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.37-46
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• 2021

Recently, social technologies have been created to solve problems from businesses for the establishment of generational solidarity ecosystem in terms of employment, residential space, network and social capital, age, cognitive and environmental aspects. This is senior-friendly healthcare business system aimed at meeting the senior needs for health life to enjoy active consumption culture life even after retirement, becoming a catalyst for minimizing generational conflicts, preventing the cognitive and physical deterioration of seniority in the areas of life healthcare, fitness and well-aging, and expanding into systems necessary for seniority self-reliance. We would like to draw up the development and requirements of the concept of the service platform for the study of collective characteristics for generation solidarity with senior class and the establishment of a customized senior health life system for generation solidarity. This system is characterized by a platform that can prevent the decline of seniors' cognitive and physical functions and enhance emotional stability. It is significant in providing feedback on the risk perception index, fall index, and prevention training index information to the child through the analysis and extraction of the senior health index for risk perception, fall probability, and fall prevention.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.6
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• pp.498-506
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• 2022

This study proposes a design methodology for bidirectional, series-resonant, dual-active bridge (SRDAB) converters. The circuit parameters of the SRDAB converters are designed by considering the output power and efficiency of the converter. The proposed method can be used to design a high-power, high-efficiency SRDAB converter. A voltage controller is employed to manipulate the output voltage of the converter, and the controller gains are selected using the transfer function and frequency response of the controller. Simulation results show that the output power of the designed SRDAB converter is 2 kW per converter module as designed. In addition, the performance of the voltage controller is evaluated using the simulation and experimental results. The output voltage follows the reference voltage within 10 ms under the step change of the reference command. The output voltage also follows the reference voltage under the step load change. The efficiency of the designed SRDAB converter is 95.6%.

• International journal of advanced smart convergence
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• v.12 no.1
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• pp.220-229
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• 2023

The development of logistics technology due to the 4th Industrial Revolution and logistics 4.0 has changed the logistics environment from offline to online, and the growth of the online market has accelerated due to the recent increase in non-face-to-face delivery due to COVID-19. Such growth in the online market has expanded the logistics market for delivery, and contributes to creating an advanced logistics ecosystem as last mile services and logistics technologies begin to grow together. As traffic and environmental problems arise as a result, interest in transportation means of cargo increases, and changes to cargo electric vehicles and delivery cycles are being considered. However, since mass transportation of transportation focused on terminal delivery such as cargo electric vehicles and delivery cycles is limited in handling large quantities in urban areas, methods for efficiently transporting cargo while considering the environment are being devised. In order to solve such environmental problems and increase the efficiency of logistics delivery in urban areas, technologies using underground spaces based on existing urban railroads are being developed. In this study, a study was conducted on the establishment of evaluation criteria for selecting a test bed, which is a space for applying the system.

• Journal of the Korean Society of Safety
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• v.38 no.5
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• pp.43-50
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• 2023

With the advent of industrialization, consumers and end-users demand more reliable products. Meeting these demands requires a comprehensive approach, involving tasks such as market information collection, planning, reliable raw material procurement, accurate reliability design, and prediction, including various reliability tests. Moreover, this encompasses aspects like reliability management during manufacturing, operational maintenance, and systematic failure information collection, interpretation, and feedback. Improving product reliability requires prioritizing it from the initial development stage. Failure mode and effect analysis (FMEA) is a widely used method to increase product reliability. In this study, we reanalyzed using the FMEA method and proposed an improved method. Domestic railways lack an accurate measurement method or system for maintenance, so maintenance decisions rely on the opinions of experienced personnel, based on their experience with past faults. However, the current selection method is flawed as it relies on human experience and memory capacity, which are limited and ineffective. Therefore, in this study, we further specify qualitative contents to systematically accumulate failure modes based on the Failure Modes Table and create a standardized form based on the Master FMEA form to newly systematize it.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.6
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• pp.589-597
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• 2015

In this paper, the live load model for the design of high-speed railway bridge is analyzed by statistic and probabilistic methods and the safety level that is given by the load factors of the load combination is analyzed. This study is a part of the development of the limit state design method for the railway bridge, and the train data collected from the Gyeongbu high-speed railway for about one month are utilized. The four different statistical methods are applied to estimate the design load to match the bridge design life and the results are compared. In order to examine the safety level that the design load combination of the railway bridge gives, the reliability indexes are determined and the results are analyzed. The load effect from the current design live load for the high-speed rail bridge which is 0.75 times of the standard train load is came out greater than at least 30-22% that from the estimated load from the measured data. If it is judged based on the ultimate limit state, there is a possibility of additional reduction of the safety factors through the reliability analysis.

• Journal of the Korean Society for Railway
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• v.19 no.6
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• pp.833-843
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• 2016

Recently, in the field of rail freight transportation, the number of trains dedicated for shippers has been increasing. These dedicated trains, which run on the basis of a contract with shippers, had been restricted to the transportation of containers, or so called block trains. Nowadays, such commodities have extended to cement, hard coal, etc. Most full freight cars are transported by dedicated trains. But, for empty car distribution, the efficiency still remains questionable because the distribution plan is manually developed by dispatchers. In this study, we investigated distribution models delineated in the KTOCS system which was developed by KORAIL as well as mathematical models considered in the state-of-the-art. The models are based on optimization models, especially the network flow model. Here we suggest a new optimization model with a framework of the column generation approach. The master problem can be formulated into a transportation problem with additional constraints. The master problem is improved by adding a new edge between the supply node and the demand node; this edge can be found using a simple shorted path in the time-space network. Finally, we applied our algorithm to the Korean freight train network and were able to find the total number of empty car kilometers decreased.