• 제목/요약/키워드: operating costs

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단독주택용 지열원 열펌프 시스템 경제성 분석 (Economic Analysis of a Residential Ground-Source Heat Pump System)

  • 손병후;강신형;임효재
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 추계학술대회 논문집
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    • pp.515-518
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    • 2007
  • Because of their low operating and maintaining costs, ground-source heat pump(GSHP) systems are an increasingly popular choice for providing heating, cooling and water heating to public and commercial buildings. Despite these ad- vantages and the growing awareness, GSHP systems to residential sectors have not been adopted in Korea until recently. A feasibility study of a residential GSHP system was therefore conducted using the traditional life cycle cost(LCC) analysis within the current electricity price framework and potential scenarios of that framework. As a result, when the current residential electricity costs for running the GSHP system are applied, the GSHP system has weak competitiveness to conven- tional HVAC systems considered. However, when the operating costs are calculated in the modified price frameworks of electricity, the residential GSHP system has the lower LCC than the existing cooling and heating equipments. The calculation results also show that the residential GSHP system has lower annual prime energy consumption and total pollutant emissions than the alternative HVAC systems considered in this work.

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장기 용수 공급계획 수립을 위한 스프레드 쉬트 모형 (A Spread Sheet Model for a Long Range Water Supply Planning)

  • 김승권
    • 대한토목학회논문집
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    • 제12권3호
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    • pp.153-162
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    • 1992
  • 시스템 분석에 의한 합리적인 장기(長期) 용수공급(用水供給) 계획(計劃)의 수립을 위하여 동적(動的) 입지선정문제(立地選定問題)의 유형으로 수학적 모형을 정립하였고, 복잡한 혼합 정수계획 문제를 푸는 대신에 스프레드 쉬트를 이용한 간단한 계산모형으로 실제적인 해를 구할 수 있음을 보였다. 분석의 결과로서는 용수 공급시설 및 용수로의 최적의 건설 시기와 기간별 최적 용수공급 운영 양상이 정해진다. 시스템 분석을 통한 합리적(合理的)인 용수공급 계획의 수립이 주먹 구구식의 계획수립에 비하여 약 15% 정도의 예산 절감(節減) 효과(效果)가 있을 수도 있음을 사례분석을 통하여 간접적으로 보여준다.

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건물에너지 소비량 해석 소프트웨어 개발 (A Software Development of Energy Consumption for HVAC System of Building)

  • 김병화;조수범;김종필
    • 대한설비공학회지:설비저널
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    • 제19권2호
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    • pp.67-81
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    • 1990
  • The objective of this is to develop a practical software package to calculate annual energy consumption of HVAC (Heating Ventilating, and Air Conditioning) System in a building. It can quickly estimate loads and energy consumption, and have a function of economic analysis through the estimation of operating cost. Techniques of save energy consumption used in a building are necessary from the stage of design process to operation. The single most significant task is on HVAC Systems. Their installation costs, and related operating costs have enormous influence upon initial and maintenance costs. HVAC designers and engineers now have a wide variety of software choices available, but only a few of them have been developed in this country and no source program has been disclosed. Neither load culculation nor estimation of energy consumption is systematically made by the domestic HVAC design firms. Even though computer improved over the years with a trend of large scale load calculation and system selection through simulaion, the utilization of software nowadays does not make good progress due to lack of working environment. Therefore, it is necessary to develop a practical software package with which load calculation can be made with ease and kind manner. This study concerns the development of a software package which makes it possible to design HVAC system and save energy consumption in operation. The algorithm used in this program is a Modified Bin Method widely known as a simplified energy analysis means.

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오픈소스 소프트웨어 도입 시 전환비용이 사용자 저항에 미치는 영향 (The Effect of Switching Costs on user Resistance in the Adoption of Open Source Software)

  • 김희웅;노승의;이현령;곽기영
    • 경영정보학연구
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    • 제11권3호
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    • pp.125-146
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    • 2009
  • 우수한 이점들을 갖춘 오픈소스 소프트웨어(OSS)의 출현은 많은 사람들에게 상당한 흥미를 불러일으켰다. 대표적인 OSS로 알려진 리눅스(Linux)에 관한 연구에서 보편적인 방법으로 개발할 경우, 약 54억 유로의 비용이 들고, 연 73,000명의 개발자들이 필요할 것이라고 추정하였다. 그러나 리눅스는 개인사용자들을 위한 운영체제 시장 점유의 0.65퍼센트만을 차지하고 있었고 이는 마이크로소프트 윈도우즈 제품이 전체의 90퍼센트를 차지하는 것과 대조적인 것이었다. OSS의 개발에 사용된 대부분의 노력들이 낭비되거나, 잠재적인 가치가 실제적으로 사용자들에게는 의미 없게 되는 결과였다. OSS의 채택은 현재의 소프트웨어의 사용을 중단함과 동시에 새로운 소프트웨어로 변경(전환)하는 것이다. 만약 사용자들이 전환하기를 주저한다면, OSS를 채택할 수 없을 것이다. 본 연구에서는 리눅스 사례를 활용하여 현재 사용하고 있는 상업성의 운영체제를 무료 운영체제(오픈소스 소프트웨어)로 전환하는 것에 대한 사용자 저항을 조사하였다. 본 연구는 전환비용을 6개의 세부유형(불확실 비용, 감정비용, 설치비용, 학습비용, 이익 손실 비용, 매몰비용)으로 분류하고, 201명의 사용자들을 대상으로 한 설문결과를 바탕으로 변화에 대한 사용자 저항에 미치는 영향을 조사하였다. 조사 결과, 변화에 대한 사용자 저항은 OSS의 채택의도에 부정적인 영향을 주는 것으로 확인되었다. 또한 본 연구는 불확실 비용과 감정비용이 변화에 대한 사용자 저항에 유의한 영향을 미치는 것으로 조사되었다. 기술 수용에 관한 선행연구들을 뛰어넘어, 본 연구는 전환비용이 변화에 대한 사용자 저항에 영향을 미치는 것을 이해하는데 공헌하고, OSS의 채택을 향상시키기 위한 전략을 개발하는 OSS 주창자들에게 제언하는데 의미가 있다.

의류 물류센터 보관효율 향상을 위한 실증적 연구 : 행거 랙 보관과 건물기둥 간격을 중심으로 (An Empirical Study on Clothing Distribution Center to Improve Storage Efficiency : Especially on Hanger Rack Storage According to Distance between Columns)

  • 남희대
    • 대한안전경영과학회지
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    • 제21권4호
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    • pp.75-80
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    • 2019
  • Sales of the Korean clothing industry grew to 16.9 percent on-year in 2010, but the growth rate dropped to 3 percent from 2011 to 2016 and the overall market began to slump to 1.1.6 percent in 2017. The competitiveness of clothing companies is also a major sector in logistics capability, and the average logistics cost of domestic clothing companies is 8.3 percent of sales in 2011, higher than the average 8 percent of domestic industries, and 36.4 percent of the total storage cost in 2011, higher than the 28.8 percent share of the total storage cost of domestic companies. As domestic production conditions such as wage hikes and labor disputes worsened in the 1990s, production facilities were rapidly moved overseas, which led many clothing companies to have no production facilities or a minimal production base in Korea and focus on marketing and design capabilities. The total storage capacity and storage efficiency of the logistics center became very important as the products were changed to the form of mass warehousing and small-volume forwarding. Research shows that building column spacing, a model of this research, can affect the amount of hanger rack storage empirically, so for sustainable growth of clothing companies, it is necessary to improve competitiveness in the logistics market by reducing costs and improving efficiency to overcome difficulties in corporate management. Because logistics costs are 8.3 percent and operating profit to sales ratio is 2 percent, it is expected that operating profit will increase by 41.5 percent if logistics costs are reduced by 10 percent. If 10% of storage cost is saved based on storage cost, operating profit is expected to increase by 15% To strengthen the competitiveness of the clothing industry, a reduction in logistics costs is essential. Therefore, the purpose of this study is to provide hints that logistics experts can have empirically small amounts in reducing storage costs through column spacing adjustment of logistics centers that have not been dealt with statistically until now, and to contribute to the continued growth of clothing companies and the development of the domestic logistics industry.

몽골기업의 이익조정과 원가의 하방경직성 (Earnings Management and Cost Stickiness: Evidence from Mongolia)

  • 벌러르토야 세르엇;구정호
    • 산업융합연구
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    • 제20권9호
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    • pp.25-38
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    • 2022
  • 본 연구는 2013년부터 2019년까지 몽골 비상장기업을 대상으로 원가행태를 살펴보고, 원가행태와 이익조정 간의 관계를 분석하였다. 이익조정이 의심되는 기업은 이익이 0에 근접하여 적자회피를 위해 상향의 이익조정이 의심되는 경우와 적자 폭이 매우 커 Big-Bath가 의심되는 경우로 구분하여 이익조정이 원가행태에 미치는 영향을 파악하였다. 본 연구의 결과는 다음과 같다. 첫째, 몽골의 비상장기업에서는 영업비용과 판매관리비는 하방경직적인 원가행태를 나타내었다. 둘째, 이익조정 구간에 따라 원가행태가 상이하게 나타났다. 이익이 0보다 약간 큰 구간에서는 영업비용, 판매관리비 모두 하방탄력적인 원가행태를 보여 상향의 이익조정 유인이 있음을 발견하였다. 셋째, 적자가 매우 큰 폭의 손실을 보고하는 구간에서는 영업비용과 판매관리비 하방경직적인 원가행태가 강화됨을 보여 Big-Bath 유인이 있음을 확인하였다. 즉, 이익조정 유인에 따라 원가행태가 상이함을 알 수 있다. 본 연구는 실증자료를 이용하여 최초로 몽골 비상장기업의 원가행태를 분석하여 경영자의 관리적 의사결정을 파악하였고, 적자기업의 이익조정 유인을 적자회피와 Big-Bath로 구분하여 원가행태와의 관계를 실증적으로 검증하였다는 점에서 의의가 있다. 몽골 비상장기업에 대한 연구가 전무한 상태를 고려했을 때 이에 대한 이해도를 높여 몽골기업에 대한 연구 초석이 된다는 점에서 의미가 있을 것이다.

저장캐러셀 설계를 위한 최소비용 모델 및 발견적해법 (A Cost Minimization Model and Its Heuristic Solution Procedure for Storage Carousel Designs)

  • 나윤균
    • 산업경영시스템학회지
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    • 제20권44호
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    • pp.179-184
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    • 1997
  • A solution procedure to minimize total carousel related costs has been developed under the carousel throughput rate and total storage capacity requirements. The carousel related costs include carousel facility costs which are proportional to the number of carousels and carousel operating costs which are directly related to the moving distances of carousels. The number of carousels is dependent upon the size of a carousel and the moving distances are determined by the size of a carousel, storage item assignment to each carousel, and the item positions in a carousel. When the storage/retrieval requirements for each storage item is equal, an optimal algorithm has been developed. When the storage/retrieval requirements is unequal, a heuristic solution procedure has been developed because of the complexity of the problem.

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유연생산시스템에서 절삭공구 비용절감을 위한 가공시간과 경로배합 최적화 (Saving Tool Costs in Flexible Manufacturing Systems: Optimal Processing Times and Routing Mix)

  • 김정섭
    • 대한산업공학회지
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    • 제30권4호
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    • pp.328-337
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    • 2004
  • Tool costs can comprise a significant part of the total operating costs of Flexible Manufacturing Systems. We address the problem of determining the optimal processing times of individual operations and routing mix in FMSs with multiple routes for each part type in order to minimize tool cost, subject to meeting a throughput constraint for each part type. The problem is formulated as a nonlinear program superimposed on a closed queueing network of the FMSs under consideration. Numerical examples reveal the potential of our approach for significant saving in tool costs.

윈도 운영시스템의 지속적 사용의도에 전환비용이 미치는 영향 (The Impact of Switching Costs on Intention to Stay with MS-Windows)

  • 현정석
    • Journal of Information Technology Applications and Management
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    • 제11권1호
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    • pp.69-82
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    • 2004
  • The role of switching costs in customer retention has been posited, but has not been subjected to rigorous empirical testing. Therefore, our main focus is on the factors that influence whether consumers will have intention to switch or stay with an incumbent technology (e.g., MS-Windows). Based on consumer survey with MS-Windows users, we find empirical support for the link between the existence of compactible software, consumer's expertise in MS-Windows and intention to stay with MS-Windows. Specifically, switching costs are found to be positively associated with the existence of compatible software. Further, the lack of expertise in MS-Windows on the part of consumers tends to increase the likelihood that they will rely on current MS-Windows, rather than switch to other alternative operating systems.

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A Dynamic Programming Model for the Project-Sequencing Problem

  • Yoo, Byeong-Woo
    • 대한산업공학회지
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    • 제5권1호
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    • pp.67-82
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    • 1979
  • For many capacity expansion problems, distinct capacity types must be specified to identify capacity at different locations or capacities with different costs and operating characteristics. In this study, a project-sequencing model is developed that allows operating costs to influence the timing decisions for project establishment. Under certain conditions, the power expansion formulation is derived that may be solved through the dynamic programming approach, and its first application to planning in electric power systems is selected to investigate an optimal policy and to show the impact of requiring system to service more than one type of demand. Several sample testing results indicate that in some systems the efficiency of the large nuclear plants is higher than that of smell ones that it may overcome the effects of the drop in reliability.

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