• 제목/요약/키워드: safety stock

검색결과 330건 처리시간 0.024초

Rolling Stock Maintenance Scheduling for High-Sneed Railway (고속철도차량의 유지보수계획)

  • 김동희;홍순흠
    • Proceedings of the Safety Management and Science Conference
    • /
    • 대한안전경영과학회 2003년도 춘계학술대회
    • /
    • pp.53-61
    • /
    • 2003
  • The process of railway traffic planning is composed of several steps such as long - term, mid - term, short - term, and real - time plan. The planning of vehicle and manpower resources is a main research topic in tactical short - term planning step Railway vehicle is usually consisted of a power car, passenger/freight cars and human resource is composed of engine driver, cabin crew, ground personnel. So far , power car was main research target in railway vehicle scheduling problem. Recently according as the light electric railway or high - speed railway is introduced, the operational planning of train set vehicles become important . In this paper , we introduce the conceptional model for trainset restoring problem and developed heuristic algorithm.

  • PDF

A simulation for stock level considering client delivery due date in auto part industry (자동차 부품산업의 고객 요구 납기 충족을 위한 적정재고 수준에 관한 시뮬레이션 연구)

  • kim, Joonghoi;Kim, Young-Chun;Kang, Kyung Sik
    • Journal of the Korea Safety Management & Science
    • /
    • 제16권2호
    • /
    • pp.131-138
    • /
    • 2014
  • Auto part industry supplies production for auto manufacturer and after market. These company have inventory for delivery. High inventory level can be good for delivery, but cost will be increase. Low inventory level can be customer unsatisfaction for delivery late. Low inventory level also is reason of low productivity by decreasing product batch size. These article suggest model for calculation a proper inventory level and prove a effect by simulation of some company.

A Parametric Studies to the Wheel Climb Derailment on the Curved track (곡선부 주행 중 타오름 탈선의 매개변수 연구)

  • Mok, Jin-Yong;Lee, Seung-Il;Lee, Hi-Sung;Hwang, Jeong-Taek
    • Proceedings of the KSR Conference
    • /
    • 한국철도학회 2006년도 추계학술대회 논문집
    • /
    • pp.72-79
    • /
    • 2006
  • Derailment is likely to have a direct connection with human life and must be eliminated. A traveling safety evaluation method based mainly on derailment coefficient has already established. But this method is very difficult because Derailment is caused by multiple factors. To evaluate the derailment factor of running train that runs on the curved track, we make use of mechanism that wheel loads and lateral forces were affected by track and rolling stock parameter. In this paper, deal with a search on the parameter and derailment factor. According to results of computer simulation value of Q/P, running safety is connected with operation velocity, curve radius, cant, track irregularity, suspension stiffness and static wheel load ratio, etc.

  • PDF

Investigation on the Service life of Disappeared Buildings in Busan (부산지역 멸실 건축물의 내구년한에 관한 실태조사연구)

  • 이재용;이수용
    • Journal of the Korean Society of Safety
    • /
    • 제18권3호
    • /
    • pp.114-119
    • /
    • 2003
  • The building needs of the community are met by the interrelated construction activities of maintaining, modernizing and replacing the existing stock of building and by the erection of additional new building. Studying the service lift of buildings and how it is determined can serve as an important measuring stick in making decisions on construction policy. Therefore, the purpose of this study is to provide useful information for future construction through a comparative and analytical study of building structures on disappeared buildings. It was found that most building structure had a shorter service life than the standard set by The Korea Appraisal Board. This situation may have occurred due to the sharp rise in replacement of older buildings with new buildings for the purpose of monetary profit. To increase the economic life of buildings reduce losses of the nation's capital henceforth, examination on policy md steady study needs to be done.

Analysis on Passenger Evacuation Flow from EMU using P*FLOW ($P^*FLOW_{(R)}$를 이용한 철도 차량에서의 승객 피난 해석)

  • Nam, Seong-Won
    • Proceedings of the KSR Conference
    • /
    • 한국철도학회 2008년도 추계학술대회 논문집
    • /
    • pp.446-450
    • /
    • 2008
  • Urban transits of metropolises have been used by many citizens due to the merits of environment friendly traffic, mass transportation, safety and scheduled operation. It is very important to keep safety for the increased passengers. When the accidents as like fire occur, rapid evacuation from fire site is one of the most effective methods to decrease casualties. Furthermore, overseas buyers sometimes request the verification results of the passenger evacuation from rolling stock. In this study, algorithm for passenger flow analysis based on DEM(Discrete Element Method) is newly developed and made simulation program package. And, we applied it to the evacuation problem for urban transits. By using the developed program, we compared the simulation results of the effects of the location and size of door and elapsed time qualitatively and quantitatively.

  • PDF

Research about Operation Status of Safety System in High speed Rolling-stock (고속철도차량 안전장치의 운영 실태 조사)

  • Ryu, Byung-Gwan
    • Proceedings of the KSR Conference
    • /
    • 한국철도학회 2008년도 추계학술대회 논문집
    • /
    • pp.1178-1187
    • /
    • 2008
  • According to the operation data between $2007{\sim}2008$(January$\sim$June) for essential safety equipment including ATC, there were nothing special but stable and steady. And also emergency stop number of count are decreasing. But the frequency are still above the resonable count and it means driving condition should be improved through interface between ground and locomotive same as come to an understanding with driver. The number of count of emergency stop for VACMA(vigilance system) are also decreasing but also the frequency are above resonable count. This phenomenon caused by careless driving for the driver or the system malfunction. So the continuous monitoring for the data is necessary.

  • PDF

Public Building Value Evaluation Using Contingent Valuation Method Based on Market Value Estimation

  • PARK, Jieun;YU, Jungho
    • International conference on construction engineering and project management
    • /
    • The 6th International Conference on Construction Engineering and Project Management
    • /
    • pp.367-370
    • /
    • 2015
  • Building deterioration reflects the degradation of basic building performance including structural performance, energy performance, durability, and safety, and it also includes perceived deterioration, which considers a user-based perspective. More than 50% of the existing buildings in Korea are over 15 years old and public buildings compose 2.5% of all buildings domestically. Therefore, there are several different problems, such as poor energy efficiency, structural performance, and safety. To address the challenges of increasing stock in deteriorated buildings, it is necessary to make decisions about reconstruction or renovation. In this study, we propose a new method to evaluate public building value with a contingent valuation method (CVM). By estimating willing-to-pay (WTP) from users of private buildings in similar situation with the public building, it is possible to compare market prices and calculate a correction factor to adjust the WTP data. Finally, we apply the correction factor to the WTP of a public building and estimate market price, willingness to pay (WTP). Finally, we apply the correction factor to willing to pay (WTP) of public building and estimate market price.

  • PDF

Strength Evaluation of Telescopic Sliding Doorstep Equipment for Railway Vehicle (철도차량 슬라이드식(텔레스코픽) 승강문 스텝의 강도평가)

  • Kim, Chul-Su;Park, Min-Heung
    • Journal of the Korean Society for Railway
    • /
    • 제15권4호
    • /
    • pp.352-356
    • /
    • 2012
  • Heights of a platform above the rail for the passenger train in the country are classified into two categories such as the low level (500mm; mainline) and the high level (1,135mm; metropolitan subway line) platforms. In order to operate similarly both a mainline railroad and a metropolitan subway line, as the requisite door safety system, it is necessary to develop the doorstep equipment of the rolling stock regardless of both the low and high level platforms. In this study, Structural analysis and mechanical strength test of doorstep equipments used for two types of platforms are performed on the supposition that the train only for the low level platform could stop in the both low and high level platforms.

A Quantitative Model for a Supply Chain Design

  • Cho, Geon;Ryu, Il;Lee, Kyoung-Jae;Park, Yi-Sook;Jung, Kyung-Ho;Kim, Do-Goan
    • Proceedings of the Korea Society of Information Technology Applications Conference
    • /
    • 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
    • /
    • pp.311-314
    • /
    • 2005
  • Supply chain optimization is one of the most important components in the optimization of a company's value chain. This paper considers the problem of designing the supply chain for a product that is represented as an assembly bill of material (BOM). In this problem we are required to identify the locations at which different components of the product arc are produced/assembled. The objective is to minimize the overall cost, which comprises production, inventory holding and transportation costs. We assume that production locations are known and that the inventory policy is a base stock policy. We first formulate the problem as a 0-1 nonlinear integer programming model and show that it can be reformulated as a 0-1 linear integer programming model with an exponential number of decision variables.

  • PDF

Technical-Economical Evaluation of Chain Vertical Alignment in Underground Urban Subways: The Case of Qom Subway, Line A

  • Abdi Kordani, Ali;Mehrara Molan, Amirarsalan
    • International Journal of Railway
    • /
    • 제7권2호
    • /
    • pp.35-39
    • /
    • 2014
  • Urban subways are one of the main parts of urban transportation networks in every city that always requires much attention in order to improve its efficiency in aspects of safety, reliability speed and costs. As the viewpoint of costs, an accurate design, especially design of vertical alignment, can have a dominant role to reduce the costs of urban railway projects. This paper seeks to evaluate the advantages and disadvantages of designing chain vertical alignment for urban subways in compare to flat vertical alignment. To achieve this goal, line A of Qom subway in Iran was selected as a case study in this research. Five parameters considered in the technical-economical evaluation: (1) energy consumption, (2) rolling stock, (3) operation, (4) civil works and geotechnical and (5) hydrological, drainage and pumping. According to the results, a power saving of about 40% have been estimated in the chain vertical alignment for the train without regenerative braking in compare with the flat vertical alignment, although the power saving was calculated less than 10% for the train with regenerative braking. Finally it was found that due to the modern rolling stock technology, the chain vertical alignment represents fewer advantages in compare to the past years.