• Title/Summary/Keyword: Operational Cost

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마이크로 그리드 운영비용 최소화를 위한 Harmony Search 알고리즘 응용 (An Application of Harmony Search Algorithm for Operational Cost Minimization of MicroGrid System)

  • 이상봉;김규호;김철환
    • 전기학회논문지
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    • 제58권7호
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    • pp.1287-1293
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    • 2009
  • This paper presents an application of Harmony Search (HM) meta-heuristic optimization algorithm for optimal operation of microgrid system. The microgrid system considered in this paper consists of a wind turbine, a diesel generator, and a fuel cell. An one day load profile which divided 20 minute data and wind resource for wind turbine generator were used for the study. In optimization, the HS algorithm is used for solving the problem of microgrid system operation which a various generation resources are available to meet the customer load demand with minimum operating cost. The application of HS algorithm to optimal operation of microgrid proves its effectiveness to determine optimally the generating resources without any differences of load mismatch and having its nature of fast convergency time as compared to other optimization method.

PBL 계약을 위한 수리부속 재고비용 예측과 V-METRIC의 활용에 관한 연구 (A Study on the Repair Parts Inventory Cost Estimation and V-METRIC Application for PBL Contract)

  • 김윤화;이성용
    • 시스템엔지니어링학술지
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    • 제13권1호
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    • pp.79-88
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    • 2017
  • For the PBL contract, it is necessary for the contracting parties to share information regarding the reasonable inventory-level and the cost of its repair parts for the estimated demand. There are various models which can be used for this purpose. Among them, V-METRIC model is considered to be the most efficient and is most frequently applied. However, this model is usually used for optimizing the inventory level of the repair parts of the system under operation. The model uses a time series forecast model to determine the demand rate, which is a mandatory input factor for the model, based on past field data. However, since the system at the deployment stage has no operational performance record, it is necessary to find another alternative to be used as the demand rate of the model application. This research applies the V-METRIC model to find the optimal inventory level and cost estimation for repairable items to meet the target operational availability, which is a key performance indicator, at the time of the PBL contract for the deployment system. This study uses the calculated value based on the allocated MTBF to the system as the demand rate, which is used as input data for the model. Also, we would like to examine changes in inventory level and cost according to the changes in target operational availability and MTBF allocation.

ICT 기반 차상제어시스템 개발에 따른 운영 이슈 분석 (Analysis of Operational Issues for ICT-based On-Board Train Control System)

  • 김영훈;최원석
    • 한국철도학회논문집
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    • 제14권6호
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    • pp.575-583
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    • 2011
  • 철도 지선 구간의 유지보수 비용을 최소화하기 위해 ICT 기반 차상제어시스템을 개발 중이다. 이 시스템은 기존의 열차제어방식과 달리 선로 주변 신호기와 고정폐색장치를 없애고 이동폐색방식을 적용하며 차상에서 선로전환기와 건널목을 제어하는 방식이다. 본 논문의 목적은 ICT 기반 차상제어시스템 개발 이전에 고려해야 할 주요 운영 이슈 사항을 분석하며 주요 대상은 열차운행준비, 운전 편의성, 관제역할, 폐색방식, 그리고 운영비용을 고려하였다. 열차 출발 전에 기관사가 DMI를 통해 입력하여야 할 입력데이터를 정의하였고 관련 업무 프로세스를 UML 도구를 활용하여 설계하였다. 기관사의 운전 편의성 측면에서는 역 진입 시의 제동시점 지원 필요성과 기관사의 원활한 운전 훈련을 위한 운전시뮬레이터가 필요하다. 기관사가 선로전환기와 건널목을 직접 제어하는 업무절차를 UML 도구로 설계하였다. 기존 운영 방식과의 차이를 확인하기 위해 고정폐색방식과 이동폐색방식 간에 비교 분석하였으며, 비용 측면에서는 기존방식과 ICT 방식의 신호설비에 따른 유지보수 비용 이점을 제시하였다.

공공부문 다기관 통합전산센터 모형에 관한 연구 (A Study on Models of Data Consolidation Center for Multi-Organization in Public Sector)

  • 임성묵;이영재
    • 산업공학
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    • 제18권4호
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    • pp.418-430
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    • 2005
  • We establish an efficient strategy for construction and operation of data consolidation center for multi-organization in public sector. First, we introduce important concepts on data consolidation center in public sector, and draw some success factors by analyzing several foreign and domestic cases. Second, we construct all the possible logical operational models of the center and investigate the properties and feasibility of the models. Third, we suggest a virtual operational environment for the two representative models selected by feasibility criteria among the possible logical models, and compare the two models in terms of operational cost. We also utilize AHP methodology to evaluate qualitative opinions on the two models from several experts in public information systems. As a result, we find the best alternative is the case in which all infrastructure and facilities for the center are provided by government, and common essential IT operations are integrated, associated data are consolidated and the whole operational work are outsourced to specialized IT operations service providers.

기능적 조직 형태에 따른 TQM 실행요소와 운영성과간의 관계에 관한 연구 (An empirical study on the relationship between Total Quality Management Practices and Operational Performance depending on Functional Organization Types)

  • 이욱기
    • 산업경영시스템학회지
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    • 제27권2호
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    • pp.1-9
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    • 2004
  • This study aims to examine the relationship between total quality management(TQM) practices and operational performance perceived by employees who are in different functional organization types, R&D function and Non-R&D function organization in manufacturing companies. Operational performance is defined as the degree of operation efficiency in the perspective of quality, delivery, and cost. Our study showed that the significant elements of TQM practice were different depending on functional organization types. In case of R&D organization, the categories of customer focus and process management were the strongest significant predictors of operational performance. Therefore, the optimal TQM practices for R&D organization can be obtained in consideration of customer focus and process management.

CONSTRUCTION EQUIPMENT ACTIVITY RECOGNITION FROM ACCELEROMETER DATA FOR MONITORING OPERATIONAL EFFICIENCY AND ENVIRONMENTAL PERFORMANCE

  • Changbum R. Ahn;SangHyun Lee;Feniosky Pena-Mora
    • 국제학술발표논문집
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    • The 5th International Conference on Construction Engineering and Project Management
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    • pp.188-195
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    • 2013
  • Construction operations generate a significant amount of air pollutant emissions, including carbon emissions. The environmental performance of construction operations is closely relevant to the operational efficiency of each resource employed, which indicates how efficiently each resource (e.g., construction equipment) is utilized. In this context, monitoring the operational efficiency of construction equipment provides key information in managing and improving the environmental performance and productivity of construction operations. In this paper, we report our efforts to measure the operational efficiency of construction equipment, using low-cost accelerometers. An experimental study and real-world case studies are conducted to demonstrate the feasibility of the proposed approach. The results have shown the potential of this approach as an economically feasible means of monitoring the environmental performance of construction operations.

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위탁급식 전문업체의 운영 현황 조사 및 현안과제 분석 (Analysis of Current Operational Practices and Issues of Contract-Managed Foodservice Companies in Republic of Korea)

  • 엄영람;류은순
    • 대한영양사협회학술지
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    • 제9권3호
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    • pp.197-208
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    • 2003
  • This study was surveyed to provide the information on current operational practices and issues of contract-managed foodservice companies. Questionnaires were distributed to 79 contract-managed foodservice companies (eight large-size, 48 mid-size, 23 small-size companies) from March to May in 2002. The contract-managed foodservice companies provided averages of 269,184 (range 140,036-503,500), 14,837 (range 450-75,269), and 4,065 (range 930-8,050) meals daily from large, medium, and small-size companies, respectively. The companies managed to averages of 268.2 (160-619) foodservice contracts at large-size companies, 21.9 (5-63) contracts at mid-size companies, and 4.7 (1-10) contracts at small-size companies. The average numbers of dietitians were 298.6 (range 104-671) in large-size companies, 22.2(6-86) in mid-size companies, and 3.8(1-9) in small-size companies. The averages of sales were 156.5 billion at large-size companies, 6.7 billion at mid-size companies, and 1.7 billion at small-size companies in 2001. The contract was two types including management fee contract(5%), and profit and loss contract(95%). The cost ratios for office foodservice were 59.5% at food cost, 24.2% at labor cost, 6.3% at profit, and 10.1% at other cost. For hospital foodservice, the ratios were 54.0% at the food cost, 34.6% at labor cost, 3.0% at profit, and 11.8% at other cost. For high school foodservice, the ratios were 62.2% at the food cost, 21.5% at labor cost, 5.4% at profit, and 11.2% at other cost. When the contractors managed to the foodservice, the most important matters were the sanitation management and customer satisfaction. Also, the difficult problems were excess investment of equipments and low meal prices.

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서울시 유치원 규모별 급식비 운영실태 및 PSM 분석을 활용한 적정 급식비 인식분석 (Analysis of Operational Meal Costs and Operator Perception of Optimal Price through an Application of the Price Sensitivity Measurement (PSM) Technique by the Size of Kindergartens)

  • 박문경;신서영;김혜영;이진용;김윤지
    • 한국식생활문화학회지
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    • 제37권4호
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    • pp.335-344
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    • 2022
  • The study was aimed to investigate the operational meal costs by kindergarten size in Seoul and to analyze recognition for optimal meal prices. A survey (31.6% recovery rate) was conducted on all kindergartens (779 kindergartens) in Seoul on April 2021 using descriptive analysis, t-test, and dispersion method. A price sensitivity measurement (psm) method was used to determine optimal meal prices. Result showed an average food cost for kindergartens of 2,647 won, an average labor cost of 605 won, an average operating cost of 146 won, and the total meal cost of 3,506 won. Total meal cost decreased with increasing kindergarten size (p<0.001). On the other hand, kindergartens with more students decreased the ratio of food cost to total meal cost, and operating cost and labor costs (p<0.001) increased. The optimal price of kindergarten operators' meal cost (OPP) was KRW 3,673. Furthermore, the analysis showed the sensitivity of operators' meal costs to kindergarten size was insignificant.

ICT기반 차상제어시스템 개발에 따른 운영 이슈 사항 분석 (An operational issues analysis of ICT-based on-board train control system)

  • 김영훈;최원석
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2011년도 춘계학술대회 논문집
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    • pp.1043-1048
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    • 2011
  • In the case of a low density branch line, these areas are operating at a loss. So much money is used for infrastructure maintenance cost. To solve the problem, our institute have a project to develop the Information & Communication Technology based train operation system. In a similar research in the Europe, The UK's Transport Research Laboratory experienced analysis of operational issue for developing ERTMS from Level II to Level III. In this paper, we study about railway operational issues before development of ICT based train operation system. An analysis target of operational issues are railway business process & data, drivability and moving or virtual block system.

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수중유도무기의 운용가용도 향상을 위한 군수지원시스템의 체계적 개발에 관한 연구 (A Study on Systematic Development of Military Logistic Support System to Improve the Operational Availability for Underwater Guided Weapon)

  • 신주환;윤원영
    • 품질경영학회지
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    • 제33권4호
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    • pp.75-87
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    • 2005
  • Generally speaking, weapon system is defined as a combination of primary system and support system which are evaluated by capability and operational availability respectively. Recently comparison of total life cycle cost shows that logistic support system is proved to be more important than primary system. However, until now systematic approach to support system development has not been applied in the area of developing support system. We need to construct a universal metric for effectiveness of logistic support system and to cut out whatever activities or support elements which do not contribute to the metric. This paper describes a new approach based on system engineering approach to logistic support system and also classifies five factors of failure, stock-out frequency, administrative delay time, active repair time and logistic delay time that have influence on operational availability of logistic support system.