• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1542-1548
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• 2010

Transportation cost takes a major portion on logistics cost. The reduction of transportation cost is a key issue to achieve national competitiveness and logistics cost reduction. And railway must play a important role to shift from road freight transport to environment-friendly transport. There are many idle freight cars in railway freight transportation and they give rise to inefficient operation of freight car. It is well known that the main reason of idle freight cars is unbalanced demand according to direction. In this study, we analysed the current status on idle freight cars in railway at the level of daily data. This results help follow-up research to cut down idle freight cars in railway.

• 한국철도학회논문집
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• 제4권3호
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• pp.116-122
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• 2001

As freight traffic becomes heavier, the high speed of existing freight cars is essential, instead of the construction of a new railway. The high speed can be achieved by the modifications of freight bogie design. In this paper, an analytical model of freight bogie is developed to decide the critical speed. The dynamic responses of the analytical model are compared with the experimental data from a running test of freight bogie and showed good agreements between them. The analytical model is used to find the design of freight bogie. The parameter studies show that the reduction of wheelset mass ratio and the increase of the axle distance of freight bogie can increase the critical speed, but the primary lateral stiffness has little effects on the critical speed. And this study also shows that smaller wheel conicity deteriorates the running safety of freight car, which means that the overhauling of the wheel of freight bogie should be done regularly.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 추계학술대회 논문집
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• pp.179-186
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• 2001

As the freight traffic becomes heavier, the high speed of existing freight cars is essential instead of the construction of a new railway. The high speed can be achieved by the design modifications of the freight bogie. In this paper, an analytical model of freight bogie including the lateral force between rail and the flange of wheel is developed to decide the critical speed, which activates a hunting motion and tells the running safety of freight bogie. The dynamic responses of the analytical model were compared with an experimental data from a running test of a freight bogie and showed good agreements between them. The analytical model is used to find the design modifications of the freight bogie by parameter studies. The results show that the reduction of wheelset mass ratio and the increase of the axle distance of the freight bogie can increase the critical speed, but the primary lateral stiffness has little effects on the critical speed. And this also study shows that smaller wheel conicity deteriorates the running safety of the freight car, which means the overhauling of the wheel of freight bogie should be done regularly.

• 대한교통학회지
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• 제27권5호
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• pp.163-168
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• 2009

통행과정의 시간 절감은 경제성 분석의 큰 편익으로 산정되는데 반하여, 화물의 운송 시간 절감에 대한 의식은 미비하다. 화물의 시간 가치를 사회적 측면에서 살펴볼 때, 운송 시간 절감이 가져오는 이익은 물류 업계에 시사하는 바가 크다. 따라서 본 연구에서는 화물운송의 시간 가치를 산정하여 운송 시간 절감의 방향을 제시하도록 한다. 품목별 시간가치를 도출하기 위한 방법으로 로짓모형을 이용하였다. 연구의 범위는 지역적으로는 경기도, 화물의 종류는 내수 5가지 품목으로 정하였으며 본문에 이용된 자료는 2007년을 기준으로 한다. 산정 결과 평균 19,946(원/대-시간)을 나타냈으며 전자부품이 가장 높은 시간가치를 나타냈다. 다음으로는 자동차 및 자동차 부품, 고무플라스틱, 정밀기기, 섬유제품 순으로 나타났다. 이를 통해 우리나라 화물운송 시간 가치의 현주소를 점검하고 물류 인프라 구축 방향을 제시하도록 한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.263-268
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• 2011

There are many exclusive freight cars in railway freight transportation system. Gondola is one kind of freight cars. Gondolas have a role to carry bulk-type cargo such as coals and ores. A few problems are occurring due to exclusive freight cars. Operation company has redundant freight cars because exclusive freight cars can carry limited items. And purchasing cost of freight cars is higher and higher because of irregular bid. Operation efficiency of gondola is very low because return time of gondola is much longer than that of container car. In this study, we analysed the introduction effect of hopper-type container for through transit. First, we identified the characteristics of spatial distribution on freight stations. And we provided the effect of hopper-type container in terms of operation efficiency, cost reduction, new demand excavation and image enhancement of eco-friendly railroad.

• 한국시스템다이내믹스연구
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• 제12권3호
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• pp.67-86
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• 2011

This study shows the reduction effect of freight volume by the supply chain redesign for the alliance of distributors with system dynamics simulation. The as-is model is composed of 3 independent companies which one has 3 distribution centers (DCS) and 24 agents, another has 1 dc and 9 agents, the other has 3 DCS and 15 agents each. The to-be model is an integrated logistics model and composed of 1 company having 5 areal DCS and 38 agents. Each agent in the same area is integrated with each other. Two models have same demands but very different result. As a result, the freight volume between DCS and agents is reduced by 33.55%. This case study will be useful to analyze the similar cases about the logistics integration by supply chain redesign.

• 무역학회지
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• 제46권6호
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• pp.163-190
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• 2021

The paper studies the impulse buying behavior of Chinese consumers during the online shopping festivals of the specific situations and their influencing factors with empirical analysis. We carried out an empirical analysis on 302 Chinese consumers with shopping experience in the online shopping festival. The study result shows that (1) marketing stimulation, preferential promotion and features of consumers have a significant positive influence on the impulse buying behavior; while the freight reduction has no significant influence on impulse buying behavior; (2) the perceived value has a significant positive influence on the Chinese consumers to have impulse buying behavior; (3) perceived value works as an in the relationship between the marketing stimulation, preferential promotion and features of consumers and the impulse buying behavior, but it has no meditating role between the freight reduction and the impulse buying behavior.

• 대한교통학회지
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• 제30권4호
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• pp.85-94
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• 2012

최근 화물운송은 물류비용절감뿐만 아니라 화물운송효율화, 녹색물류를 추구하고 있으며, 이를 지원하기 위한 방안으로 물류시설 경유 및 다수단간 복합운송을 지향하는 교통물류정책들이 활발히 논의되고 있다. 이러한 추세에 따라 관련 화물통행수요 분석 방안의 변화가 필요한 시점에 이르렀다. 그러나 국내에서는 화물통행수요모형 개발에 대한 논의가 미흡한 상황이며, 특히 중간경유지에서의 수단간 환적 등의 물류활동을 고려하고 있지 않아 물동량 추정의 신뢰성 및 현실성에 한계가 있다. 따라서 본 연구에서는 화물의 순물동량과 총물동량을 고려하여 복합수단교통망에서의 물류시설 경유여부 및 수단간 환적 등의 물류활동을 분석할 수 있는 화물통행수요분석 방안을 제시하였다. 또한 사례품목에 개발된 방법론을 적용함으로써 물류시설 신설 또는 변경에 따른 수단간 전환 효과를 분석에 본 방안의 적용가능성을 살펴보았다.

• 한국기계가공학회지
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• 제17권1호
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• pp.130-137
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• 2018

In long freight trains, there is a brake time delay in the neighboring freight cars that causes damage and fractures of couplers, especially the knuckle of them. If there is a problem for couplers in the cars, this could cause a derailment and lead to damage of human life and property damage. In this study, maximum forces on the couplers are studied when a long freight car brakes, with brake delay time and coupler gap. We have made a dynamic model of 50 freight cars and couplers, applying contact between couplers and a characteristic curve for expressing force and displacement of buffers with SIMPACK, a multi-body dynamics program. We use EN 14531-2 from the British Standards Institution, a standard of freight car brakes for the verification of the dynamic model. We also use a simplified method to analyze the dynamic model of 50 freight cars. With changing coupler gap and brake delay time, we do comparative analysis with AAR M-201 from the Association of American Railroads, a standard of AAR couplers. From this result, we find that the standard on fatigue limit is satisfied, such that the brake delay time is within 0.06 second if the coupler gap of the AAR coupler is within 20 millimeters.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2455-2462
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• 2008

Global warming has become one of the most important social responsibilities. After Kyoto protocol for greenhouse gas reduction by climatic change convention came into effect, developed countries are presenting various policies to reduce greenhouse gas that is produced in transport field. One of those policies is modal shift that change from road freight to sea, inland waterway and railway transportation that is eco-friendly. Because increase of road freight brings about road congestion and accident, logistics cost, air pollution and green house gases. Railways are superior to all other modes of transport in mass transportability, high speed, timeliness, safety and environmental-friendliness, but the railway industry has been pushed behind in competition. In developed country's government actively promoted relevant legislation, policies, and countermeasures known as modal shift policies to shift freight transport from road to large volume mode such as railway and ship. In this paper, we discuss the current situation in modal shift, compare it with cases in other countries EU and Japan, identify problems in Korea, and propose the following ways to enhance competitiveness of rail freight.