• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.321-324
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• 2008

Recently, there is an increasing demand for efficient high power/weight auxiliary power supplies for use on high speed traction application. many new conversion techniques have been proposed to reduce the voltage and current stress of switching components, and the switching losses in the traditional pulse width modulation(PWM) converter. Among them, the phase shift full bridge zero voltage switching PWM techniques are thought most desirable for many applications because this topology permits all switching devices to operate under zero voltage switching(ZVS) by using circuit parasitic components such as leakage inductance of high frequency transformer and power device junction capacitance. The proposed topology is found to have higher efficiency than conventional soft-switching converter. Also it is easily applicable to phase shift full bridge converter by applying an energy recovery snubber consisted of fast recovery diodes and capacitors.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.742-749
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• 2008

In 21th century, high oil price and environmental pollution appeared by serious social problem. It brought important change of logistics environment, and environmentally-friendliness and sustainability are emphasized. In spite of that railroad has high energy efficiency and environmental-friendliness to advantage traditionally, there is still transport division rate of railroad in declining tendency as investment policy that is concentrated on road and insufficiency of social realization about environmental problem. The construction of environment-friendly transport system and the reasonable role sharing between modes of transportation are important. Transportation policy of Korea is presented through plans to constructs efficiently and manages national transportation system. In this study, examine development process of national railroad logistics plan with logistics environment change, and proposes the following ways to development of railroad logistics policy.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1689-1696
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• 2008

Heat pumps transfer heat by circulating a substance called a refrigerant through a cycle of evaporation and condensation. But Heat pumps system by only using heat-source is not efficient. Because the mean temperature of North Korean winter season is low, economy of air heat-source heat pump descend. This paper is practiced the simulation on evaluation criteria for Heat pump heating and cooling systems to Rolling Stock. Efficiency of the heat pump in order improving from certainly the development of the technique will be able to prevent a freezing actual condition must proceed. As a result, Below $-10^{\circ}C$ used heating and cooling systems of heat pump format even in cold winter season and is serviceable confirmed with heat source supply circle of the Rolling Stock.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1799-1802
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• 2008

More than 7 million people use the Seoul metropolitan subway network daily. This number tends to increase due to the increase of oil price. Indoor air quality of electrical multiple unit (EMU) is strongly affected by outdoor air quality, however, indoor thermal comfort is subjected to heating, ventilating, and air conditioning (HVAC) system of EMU. In general, air temperature, humidity, air velocity, surface temperature, and illumination are key parameters affecting thermal comfort of passenger. It is known that the well-designed HVAC system should improve the thermal comfort of passengers and should increase the energy efficiency of HVAC system also. In this study, we analyzed the thermal comfort of advanced EMU developed by Korea Railroad Research Institute by using the computational fluid dynamics (CFD) in order to find the optimum HVAC system which can improve thermal comfort of passengers with a minimal energy use.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.162-168
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• 2008

To predict efficiency of Interior Permanent Magnet Synchronous Motors(IPMSM) and to cope with the demagnetization risk of permanent magnets used in the IPMSM, accurate iron analysis of the IPMSM is very important at the motor design stage. In the analysis, we developed a new iron loss model of electrical machines for high-speed operation. The calculated iron loss was compared with the experimental data. It was clarified that the proposed method can estimate iron loss effectively at high-speed operation.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.536-543
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• 2008

When the electric motor car was first introduced, an engineer, responsible for the work related to operation and a conductor for the announcement and management of entrances and the other services like as monitoring the passengers in the platforms used to take together the train for passengers' safe. As new technologies developed and the urban transit system had the automatic driving facilities, automatic door switch and broadcasting systems, to solve the financial problems, most subway systems introduced the one-man operation system. To curtail the operating expense through automatic control and operation for the economical efficiency, the crewless driving system was introduced abroad around 1970 on the light weight train and Japan started the crewless driving system in 2005, Germany started it in June 2008. We examine system requirements of the system and methods to construct safe systems that would be introduced, suitable for one-man operation system or crewless driving system through the surveys and analysis of driving state and the systems.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1029-1037
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• 2008

As for track maintenance, Seoul Metro executes track bed improvement project from obsolete ballast track bed to concrete track bed in order to achieve maintenance free and to extend its LCC(Life Cycle Costing). When it comes to obsolete ballast track bed withdrawal task, now it is done solely relying on man power and ballast inhalation vehicle. In this paper, I suggested ballast cleaning system with lighter equipment to change manpower withdrawal tasks to mechanized ones. It is expected to improve work efficiency and economic benefits by applying track excavator having variable wheels and container etc, which is able to keep on the site.

• 대한안전경영과학회지
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• 제24권1호
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• pp.1-9
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• 2022

The growth of the online market is accelerating due to the development of technology and the pandemic era. The delivery service through the courier must be used to deliver the ordered goods to the customer through the online market. With the growth of the online market, the logistics market for delivery is also growing. The traffic and environmental problems are emerging as social issues. Urban logistics technology using underground space based on the urban railway developed to improve logistics efficiency in a metropolitan area and a new alternative to environmental problems. This study proposed a plan to secure system safety through safety analysis based on operational concept definition and scenario analysis by applying model-based perspective analysis to the system under development.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1054-1061
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• 2009

본 연구에서는 현재 국내외적으로 설치가 이루어지고 있는 PSD에 대하여 설치 유무에 따른 화재유동 변화와 배연효율변화에 중점을 두어 연구를 진행하였다. 시뮬레이션 모델은 대구지하철 중양로 역사이며, 승강장과, 대합실 2개층을 포함하여 화재해석을 수행하였고, 화재해석 프로그램은 FDS를 사용하였다. 역사 전체를 모델링함에 따른 격자수 증가로 많은 계산시간이 소요되므로 병렬처리 기법을 통한 화재해석을 수행하였다. PSD 유무에 따른 화재유동 및 배연효율 변화의 비교를 위하여 화재사나리오를 작성하여 Case 별로 화재해석을 수행하였다. 화재규모는 NFPA-130 을 참조하여 10Mw 상황에서의 화재유동 을 연구하였다. 해석 결과는 NFPA-130을 참고하여 승객안전에 중점을 두어 분석하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2493-2502
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• 2011

소프트웨어 RAMS를 위한 소프트웨어 코드의 정적 분석을 위해서 경험 있는 테스터들은 안전에 고장을 야기시키는 정적 기법을 선별적으로 사용하여 결함을 검출하기를 선호한다. 코딩 규칙, 소프트웨어 메트릭스, 위험데이터 등의 정적 기법들의 많은 사례들이 보고되고 있다. 그러나 다수의 분석 사례들은 정적 분석의 효과를 이론적으로만 제시할 뿐, 코드 분석에 사용된 코드 결함들을 테스터가 어떻게 판단하여 분류하고 이를 높은 품질을 보증하기 위해 올바르게 제거 수정하였는가에 대한 구체적인 설명이 부족하다. 간혹, 일부 사례를 통해서 그 효과를 제시하는 자료들도 있으나 그 적용과정이 구체적이지 않아 신뢰를 얻기가 어려운 경우가 많다. 본 논문에서는 안전성 화보를 위해 철도분야에서 많이 사용되는 정적 기법들을 소개하고 이들을 실제 개발 과제에 적용하여 각각의 결과를 비교하고 분석하였다. 본 논문의 결과를 일반화하기는 어려울 것이지만 하나의 사례 연구로서 참고하고 활용될 수 있을 것이다.