• Journal of the Korean Society for Railway
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• v.20 no.2
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• pp.196-202
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• 2017

A very long test track is required for high-speed operation test of the real-scale Linear Synchronous Motor (LSM) for ultra-high-speed trains. The required length results in huge construction cost and economic loss if any error occurs during development. Therefore, validation study of the LSM design technology using a low-cost small-scale model must be carried out in the early research stages. It is possible to deduce an optimal winding method for the armature and determine the mechanical properties of the LSM through a performance tester that applies a rotary-type small-scale LSM model. In addition, it is possible to utilize previous research on LSM control systems. Therefore, a basic design model, comprising a rotary-type LSM tester that meets the requirements for the propulsion of 600km/h-class ultra-high-speed trains, is derived in this study. Finally, an optimal model, which has a stable structure under the condition of 1500rpm or more high-speed rotation, is derived by electromagnetic and mechanical stiffness analysis.

• Environmental Engineering Research
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• v.24 no.4
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• pp.680-689
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• 2019

Temperature effects on the generation of brake wear particles from railway vehicles were generated, with a particular focus on the generation of ultrafine particles. A real scale brake dynamometer test was repeated five times under low and high initial temperatures of brake discs, respectively, to obtain generalized results. Size distributions and temporal patterns of wear particles were analyzed through visualization using clustered heatmaps. Our results indicate that high initial temperature conditions promote the generation of ultrafine particles. While particle concentration peaked within the range of fine sized particles under both low and high initial temperature, an additional peak occurred within the range of ultrafine sized particles only under high initial temperature. The timing of peak occurrence also differed between low and high initial temperature conditions. Under low initial temperature fine sized particles were generated intensively at the latter end of braking, whereas under high initial temperature both fine and ultrafine particles were generated more dispersedly along the braking period. The clustered correlation heatmap divided particle sizes into two groups, within which generation timing and concentration of particles were similar. The cut-off point between the two groups was approximately 100 nm, confirming that the governing mechanisms for the generation of fine particles and ultrafine particles are different.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1837-1844
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• 2014

The study of safety culture estimate has received a wide attentions in many other industries, rather in the contexture of railroad stands at an initial phase. A factor analysis and internal reliability test were conducted to check if the survey results are reliable by looking at how the factors are dimensioned and how the questionnaires are sub-grouped in accordance with such factors, and further if there are any other common attributes being extracted as a new factor. The designed 5 factors were expanded to 7 through the test, and they were renamed accordingly. The questionnaires are reorganized according to the new 7 factors. It implicates that thorough investigation of the common attributes is important in reducing the gaps between interviewers' and interviewees' understanding. Moreover, the results of internal reliability test represent the new design of questionnaire is reasonably acceptable with the high reliable values. We expect such approaches can be applied for the railway culture survey study to be more reliable and applicable.

• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.939-946
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• 2005

The stiffness properties of heterogeneous concrete materials and their degradation were investigated at different-levels of observations with aids of the opportunities and limitations of multi-resolution wavelet analysis. The successive Haw transformations lead to a recursive separation of the stiffness properties and the response into coarse-and fine-scale features. In the limit, this recursive process results in a homogenization parameter which is an average measure of stiffness and strain energy capacity at the coarse scale. The basic concept of multi-resolution analysis is illustrated with one and two-dimensional model problems of a two-phase particulate composite representative of the morphology of concrete materials. The computational studies include the meso-structural features of concrete in the form of a hi-material system of aggregate particles which are immersed in a hardened cement paste taking due to account of the mismatch of the two elastic constituents.

• Journal of the Korea Convergence Society
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• v.8 no.3
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• pp.41-48
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• 2017

The TAGO and TOPIS systems have limitations in providing not only information collection problems but also customized information that meets the requirements of users in providing information. In addition, there is a lack of integrated link information for various means. In addition, there is a limitation in using public transportation because all the users can not conveniently use public transportation because of lack of user - customized information and traffic - related information. In this paper, in this paper, we analyze the current status of domestic and international public transport information systems and services, Through this, we expect to be able to provide customized information tailored to the requirements of users by providing integrated linking information for various means.

• Journal of the Korean Magnetics Society
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• v.21 no.2
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• pp.61-66
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• 2011

The miniaturization of electrostatic precipitator is becoming a key element to the success of the efficient electrostatic precipitator due to the limited space allowed to install electrostatic precipitator in subway tunnel. Nowadays, a research on electrostatic precipitator in urban railroad equipment technology is under an active study. Finite element method has been used one of the most popular techniques, but it consumes a lot of time especially in computation iterations. Accordingly, the lumped parameter analysis can be an alternative tool to FEM because of its computation iteration capability with fair accuracy. In this paper, lumped parameter model and the simulation results are presented. In addition, the result of lumped parameter analysis is compared with those obtained from finite element analysis for verification.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.501-509
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• 2008

It is very important in designing civil engineering structures that the quantification of geological informations must be carried out in terms of importance. In this study, the geological informations are quantified and evaluated using analytic hierarchy process (AHP). A professional group was organized with 30 people in the field of civil engineering, transport, and geology. On the assumption that the civil engineering structure is linear such as highway or railroad, a survey of the group in terms of geological and hydro-geological elements has found that the hierarchy structure is composed of four levels. And fault structure is a primary factor which causes the stability of a linear civil engineering structure. The importance of geological items are arranged with fault (0.456), foliation/bedding plane(0.l65), lineation(0.144), ground water(0.124), and rock type(0.111).

• Journal of Navigation and Port Research
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• v.35 no.6
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• pp.509-514
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• 2011

The purpose of this study is to provide some ideas for the improvement of the seafarers physical examination systems(PES) in Korea. This paper presents basic data about the items and detailed standards of the seafarers PES which are currently carried out worldwide. In this paper, a comparative analysis of the domestic and the foreign seafarers PES is conducted. In addition, rule of judgment in the railroad workers PES in Korea has been examined for reference. The paper proposes the amended and supplemented 16 items and detailed standards of the seafarers PES. Expert opinions of Occupational and Environmental Medicine specialist and the recommendations of ILO/WHO are also considered to draw an improvement scheme for the seafarers PES in Korea.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.74-79
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• 2016

The Seoul Metropolitan Subway, which started operating in 1974, plays a major role in transporting 7,289 thousands passengers daily. This trend of a steadily increase in passengers from 2012 has increased the congestion rate because of the limited capacity and time. To solve this problem, Seoul city is consistently working on improving the subway facilities, such as the construction of a detour path. This project, however, has only a slight effect on improving the congestion rate and is too expensive to construct the facilities. Hence, this study suggests The Congestion Standardization System based on the IoT for improving the subway congestion rate. Based on the system, the expected effect analysis was performed, which resulted in a decrease in ride passengers from 34 to 20. In addition, this expected effect analysis shows that the number of subway vehicles can increase from 20 to 24. The suggested system will have a significant effect on the efficiency of the management system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2534-2540
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• 2010

In this paper we propose contents and results on installation and commissioning test for ATP on-board unit, which has propelled as one of the research projects, so called, "Reliability assessment and operation technology development for Korean-type tilting trains" in order to ensure the safety and operation efficiency of tilting trains. In KRRI, we have developed tilting trains for the speed-up of existing lines and for the passenger service improvement where the KTX is not available. And we also make progress the operation trial test at the speed of 10km with the use of ATS units, used in existing lines, for the purpose of the reliability assessment of the developed tilting trains. In MLTM, they have decided to accelerate the speed at more than 200km/h for the 7 existing lines including Jungang-line and Chungbuk-line where KTX has not operated. According to this decision, Train control system is to be changed from ATS to ATP. We should install an ATP on-board unit in tilting trains and verify the operational suitability. Therefore, we have installed and tested the same ATP on-board unit on tilting trains that used in the ATP construction project on Gyeongbu-line and Honam-line.