• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.224-232
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• 2020

This study aimed to verify the relationship of a city's history and identity through an architectural assets survey of Daejeon Metropolitan City. To achieve these purposes, the architectural assets survey was carried out, and the characteristics were reviewed. The results of this study are as follows. (1) The architectural assets are composed of 86.5% buildings, 7.4% space environments, and 6.1% infrastructure. (2) Of the architectural assets, 52.7% were constructed in the 1960s~1980s, and 25.0% were built before the Korean War. (3) The physical characteristics of the architectural assets are represented by the single floor, housing and religious facilities, traditional Korean roof tiles, and cement mortar and wood finishing. The characteristics of the architectural assets of Daejeon Metropolitan City are related to the allocation of public offices, banks, and government buildings after the relocation of Chungnam-Do Province Office in the 1930s, and reconstruction and revival around Daejeon station after the Korean War. In particular, the accumulation of Hanok for the shrine in Isa-dong and the townhouse for railroad officers in Soje-dong represent the regional and modern history of Daejeon Metropolitan City.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.6
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• pp.991-999
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• 2018

In urban areas, the proportion of railway traffic in public transport is increasing. The congestion situation is repeated as the passengers concentrate on station and transfer facilities and the inconvenience of the passengers is increasing in terms of safety and convenience. Therefore, the importance of estimating the appropriate area of the station has been emphasized. The area estimation formula used in the metropolitan railway stations currently is a partial modification of the area estimation formula of Japan in the 1970s. It does not reflect changes in the social and cultural environment and patterns of passengers. The technical basis for major decision variables is insufficient. Therefore, the theoretical basis of the area estimation formula and the pedestrian environment satisfaction of the design guideline of metropolitan railway stations were analyzed in order to suggest improvement formula. The improved area estimation formula was verified by conducting field surveys on 5 stations of metropolitan railways and 15 stations of urban railways. The existing area estimation formula is LOS E grade for the main space. However, the LOS D grade is implemented when the improved area estimation formula is applied. Based on the results, the design factors for the area estimation formula are suggested.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3889-3894
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• 2012

The platform of railroad station for domestic passenger train has been operated at two categories like the platforms if low level(500mm, mainline) and high level(1,135mm, metropolitan subway line). To operate both metropolitan subway line and mainline railroad safely, it is essential to develop the doorstep equipment of railway vehicle regardless of low and high level platforms. On the other hand, the domestic test standard at durability and reliability of doorstep equipment has not been existed until now. This study aims at the development on doorstep equipment of telescopic sliding type for low and high level platforms. Durability analysis with VPD(Virtual Product Development) techniques are performed and the durability standard & qualification life through the rig test during no failure test time is examined in accordance with reliability qualification test.

• Journal of the Korean Society for Railway
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• v.19 no.5
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• pp.565-575
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• 2016

Wheel reprofiling is frequently conducted to remove faults such as flange wear, flat areas, and cracks that occur in railway vehicle operation. We analyzed the dynamic performances of a vehicle before and after wheel reprofiling to grasp the influence of reprofiling on the dynamic behavior of the vehicle. We measured the wheel profile of the test vehicle and conducted a running test to analyze the vibration and comfort characteristics of the test vehicle. The result of the test indicated that vibration of the test vehicle after wheel reprofiling was reduced compared to that before wheel reprofiling. And, comfort level of the test vehicle after wheel reprofiling was improved by about 3dB laterally and vertically. Consequently, the positive effect of wheel reprofiling on the dynamic performance of vehicle was verified.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.6
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• pp.106-113
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• 2017

In this paper, we propose a suitable network topology for the Ethernet based Train Communication Network (TCN) for control system in a autonomous multi-articulated vehicle. We propose a network topology considering the structural constraints such as the number of cables and ports, and the performance constraints such as network response time and maximum throughput. We compare the network performances of star topology and daisy chain topology as well as hybrid topology, which is proposed in previous studies and a compromise between daisy chain and star topology. Here, the appropriate number of nodes in a group is obtained for the configuration of the hybrid topology. We first derive estimates of the network performance through simulation with different topologies, and then, implement the network by connecting the actual devices with each network topology. The performance of each topology is measured using various network performance measurement programs and the superiority of the proposed topology is described through comparison.

• Journal of the Korean Geotechnical Society
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• v.33 no.8
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• pp.5-16
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• 2017

When a lateral load is applied to a short pile whose embedded depth is relatively smaller than its diameter, an overturning failure occurs. To investigate the behavior of laterally loaded short piles, several model tests in laboratory scales had been carried out, however the behavior of large moment carrying piles for electric poles, traffic sign and road lamp, etc. have not been revealed yet. This paper deals with the real-scale load tests for 750 mm diameter short piles. To simulate the actual loading condition, very large moment was mobilized by applying lateral loads to the location 8 m away from the pile head. Three load tests changing the pile embedded lengths to 2.0 m, 2.5 m, and 3.0 m were carried out. The test piles overturned abruptly with very small displacement and rotation before the failures. These brittle failures are in contrast with the ductile failures shown in the former model tests with the relatively smaller moment to lateral load ratio. Comparisons of the test results with three existing methods for the estimation of the ultimate lateral capacity show that the method assuming the rotation point at pile tip matches well when the embedded depth is small, however, as the embedded depth increases the other two methods assuming the inversion of soil pressure with respect to rotation points in pile length match better.

• Journal of the Korean Society for Railway
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• v.16 no.4
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• pp.278-285
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• 2013

The suppression of residual settlement is required on earthwork sections as concrete track is introduced. Use of pile-slab structure is one of the settlement restraining methods applied on soft ground. The slab distributes the upper embankment load and piles transfer the load from the slab to the stiff ground. While this method is very effective in terms of load transfer, it has not yet been established for dealing with the vibration transfer effects and interaction characteristics between a structure and the ground. It is possible that vibration caused by a moving train load is propagated in the upper embankment, because the slab acts as a reflection layer and waves are multi-reflected. In this present paper, wave propagation generated by a moving train load is evaluated in the time and frequency domains to consider a roadbed structure using an artificial impact load and field measured train load. The results confirmed the wave reflection effect on the pile-slab structure, if the embankment height is sufficient, vibration propagation can be stably restrained, whereas if the height is not sufficient, the vibration amplitude is increased.

• Journal of the Korean Society for Railway
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• v.19 no.3
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• pp.297-303
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• 2016

This paper introduces auxiliary power supply systems (APS) for railroad applications and proposes a new power conversion structure for highly-efficient and lightweight APS systems. The proposed structure focuses on an improvement of the power density in APS. It eliminates unnecessary power conversion stages in the conventional APS structure by modulating the dc/dc converter circuit and the structure of the system. The dc/dc converter circuit used in the proposed structure is based on a multi-level half-bridge converter, a widely used topology in railroad APS applications; a flying capacitor is newly added to the conventional circuit. The added capacitor is used not only to enhance the soft switching condition of the switches, but also so that the new pantograph will have a side voltage source of a battery charger in the APS structure. Since the battery charger uses the pantograph side voltage source in the proposed structure, rather than using the output of the main dc/dc converter in the conventional structure, the size and efficiency of the main dc/dc converter are reduced and increased, respectively. To verify the effectiveness of the proposed structure, simulation results will be presented with metropolitan transit APS specifications.

• Journal of Korean Society of Transportation
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• v.32 no.4
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• pp.327-335
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• 2014

The Korean government, as of last year, is attempting to introduce a competitive system in the rail-market. However there are some pertinent issues which need to be addressed in order to select the best possible organization for optimum railway traffic control. As there are no standard guidelines in selecting an agency, objective evaluation factors need to be properly applied to ensure the best possible decision is made. Through literature review and various interviews with experts, appropriate criteria were selected to evaluate the suitability of each potential operator. As generally mentioned, both safety and efficiency play vital roles in the selection process but in addition, there are other factors such as security and fairness, which also need to be considered. The individual weight of these factors were calculated by the AHP, in which three groups of experts were interviewed to acquire their expertise. According to the results, as a potential operator, the score of a railway operating company and the management cooperation of railway is 2.75 and 3.85, respectively. In the future, in preparation towards becoming a competitive rail-market, this research is expected to assist in choosing the best party to control the rail traffic system.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.907-914
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• 2011

It has used for Rolling Stock Maintenance a number of maintenance system applied RCM in Railway(Korea Railroad Corporation, Seoul Metro, Korail Airport Railroad Corporation, etc) so far. Some institutions has been using develop Computational System including reliability process. A majority of the system has computerized maintenance work, but it is shown that developed focus on administrator and developer not user. SMRT(Seoul Metropolitan Rapid Transit Corporation) has developed computational system for maintenance in the '90s and saved many data about Maintenance Historical Data. However, this system reached the limits application of this data. Maintenance of computer systems is managed directly by the field staff and to introduce Reliability-centered maintenance SMRT was continually reviewed system development trends and supplement the existing system. To successfully operate RCM program should be gained full support in the whole company and field communicate, secure a reliable data from field and the most important take a patience. Our corporation will operate and develop successful RCM thorough review of these problems in the future.