• 한국농공학회논문집
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• 제50권4호
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• pp.51-58
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• 2008

Unit costs for energy production in bioenergy facilities are dependent upon both fixed cost for facility construction and operational costs including biomass feedstock supply. With the increase of capacity, unit fixed cost could be decreased while supply cost tends to increase due to the longer transportation distance. It is desirable to take into account biomass availability in planning bioenergy facilities. A cumulative curve relationship was proposed to relate biomass availability and cumulative products of biomass amount and transportation distance. Optimum size of gasification facilities was affected by collection cost, biomass cumulative relationship. Based on biomass availability of Icheon-City, optimum sizes were about $400kW_{th}$ for gas production, and about $200kW_{el}$ for power generation. Unit cost of bioenergy production could be substantially reduced by reducing collection cost through supplying biomass from diverse sources including land development areas where significant amount of waste wood is generated. When planning bioenergy facilities, however, biomass availability and spatial distribution are key factors in determining the size of capacity.

• Industrial Engineering and Management Systems
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• 제9권2호
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• pp.107-120
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• 2010

In today's uncertain economic environment, the evaluation of safety for investment alternatives is of practical importance in manufacturing companies. This paper examines a method of quantitatively evaluating profitability and risk for multiple alternatives using the total-cost unit-cost domain. The paper assumes such factors as unit sales price, sales and production volume, unit variable cost, fixed cost, and yield for each alternative. The paper incorporates the relationship between production capacity and demand, distinguishing between cases of production capacity surplus and shortage for each year over the entire planning horizon. The paper investigates the case in which the values of each factor independently move in the direction of decreasing profit each year, and clarifies the procedure of comparing safety among multiple investment alternatives on a single consolidated total-cost unit-cost domain. The difficulty of the problem lies in the method of consolidating multiple total-cost unit-cost domains into a single domain since the combination of years of capacity surplus and shortage depends upon the change values in each factor under consideration. A systematic method of evaluating profitability as well as risk is presented, and the validity of the proposed method is verified using a numerical example.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.187-189
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• 2011

Standard production unit system has been used as accumulated standard for the cost estimation of public construction projects. However, it is difficult to estimate reasonable cost due to adaptation of a uniform standard and reflect changes in the technology. The purpose of this study is to provide basic data for improvement of standard production unit system through the identifying problems and analysing its influence on enactment and/or revision work of standard production unit system.

• 한국수소및신에너지학회논문집
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• 제31권4호
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• pp.337-344
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• 2020

Worldwide, there is a significant surge in the efforts for addressing the issue of global warming; the use of renewable energy is one of the solutions proposed to mitigate global warming. However, severe volatility is a critical disadvantage, and thus, power-to-gas technology is considered one of best solutions for energy storage. Hydrogen is a popular candidate from the perspective of both environment and economics. Accordingly, a hydrogen production system based on renewable energy sources is developed, and the economics of the system are assessed. The result of the base case shows that the unit cost of hydrogen production would be 6,415 won/kg H₂, with a hydrogen production plant based on a 100 MW akaline electrolyzer and 25% operation rate, considering renewable energy sources with no electricity cost payment. Sensitivity study results show that the range of hydrogen unit cost efficiency can be 2,293 to 6,984 Won/kg H₂, depending on the efficiency and unit cost of the electrolyzer. In case of electrolyzer operation rate and electricity unit cost, sensitivity study results show that hydrogen unit cost is in the range 934-26,180 won/kg H₂.

• 한국산업융합학회 논문집
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• 제25권6_3호
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• pp.1207-1219
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• 2022

「Act On Contracts To Which The State Is A Party」 stipulates that the "Construction Standard Production Rate" and "Construction Standard Unit Price" be used as the criteria for determining the estimated price of construction works performed by public institutions. In this regard, issues such as the application scope of the Construction Standard Unit Price, and the effect of budget reduction continue. However, due to the lack of quantitative data on the actual application of Construction Standard Unit Price, it is difficult to objectively evaluate various issues. In order to prepare data for objective evaluation of the Construction Standard Unit Price, this study analyzed the ripple effect of applying the Construction Standard Unit Price based on the bill of quantity. As a result of the analysis, the Construction Standard Unit Price ripple effect in the civil engineering part was 9.2%, and it was analyzed that there was a ripple effect of about 1.9% based on the civil engineering direct cost. In the construction part, the ripple effect was analyzed to be relatively high at 17%, but it was found to have a ripple effect of about 3% in the construction direct cost. Based on the total direct cost, the ripple effect was calculated as 2.2%. Based on the analysis results, it is possible to evaluate the effect of applying the Standard Market Unit Price, and it is expected to be used as basic data to solve issues. As a future study, it is necessary to additionally analyze the ripple effect by Standard Market Unit Price application range (over 10 billion, over 20 billion won, etc.) and delivery system type (comprehensive evaluation, qualification examination, technical bidding, etc.). In addition, it is necessary to study the appropriate ripple effect of the Standard Market Unit Price.

• 한국건축시공학회지
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• 제14권5호
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• pp.477-485
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• 2014

표준품셈과 실적공사비 적산방식은 건설공사의 예정가격을 산정하는 가장 대표적인 기준자료이다. 하지만 이러한 공사비 산정방식은 1일 작업량 미만의 작업에서 정의, 할증 또는 보정기준 등이 명확하지 않아 적정 공사비의 산정이 어려운 실정이다. 따라서 본 연구는 1일 작업량 미만의 작업에서 표준품셈과 실적공사비의 문제점을 파악하고 이에 대한 개선방안을 제시하고자 한다. 이를 위해 본 연구에서는 경기도내 44개의 전문건설업체에 대하여 설문조사를 실시하여 빈도분석을 하였다. 본 연구를 통하여 표준품셈에서는 인건비, 실적공사비에서는 장비비, 공종별로는 도로포장 및 유지공사의 장비비가 각각 가장 높은 비율로 초과되었다는 결과를 도출하였다. 결과를 바탕으로 표준품셈과 실적공사비는 공사의 규모에 따른 구분 등 각각 3가지의 개선이 필요하다. 본 연구의 결과는 1일 작업량 미만의 작업에서 공사비 산정 제도의 개선을 위한 기초자료로 활용될 수 있을 것이다.

• 대한조선학회논문집
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• 제28권1호
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• pp.197-205
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• 1991

생산계획 최적화를 도모하기 위하여 선박조립공정을 구성하는 소 생산단위인 activity에 대한 수학적인 cost model을 수립하는 방법을 제시하였다. 이 cost model의 수립은 실제로 work study 방법을 이용하여 작업자수와 작업시간간의 관계식을 작성하고 Marginal costing 개념을 이용하여 해당기업의 연간 총 cost를 각 생산자원의 사용량에 분배하여 단위공수 및 단위시설 사용량에 대한 cost를 산출함으로서 이루어진다. 이 방법을 실제의 한 activity의 예에 적용하여 보고 일반적인 방법을 제시하였다.

• 한국건설관리학회논문집
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• 제16권1호
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• pp.110-118
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• 2015

표준품셈은 우리나라 건설공사에 있어 가장 기본적인 요소이지만, 표준품셈이 공동주택 건설공사에서 실제 투입 되는 노무량과 큰 차이를 나타내고 있다. 따라서 실적공사비방식에 의해 공사비를 산정하는 것이 합리적인 대안이 될 수 있으나 원가계산서상에 각종 경비 등에는 정확한 노무량을 파악하여야 비용이 산출될 것이며 공사 진도 관리를 위해 투입 노무량을 정확히 파악할 필요가 있다. 본 연구는 2000년 이후 준공 된 수도권에서 공동주택 건설공사에서 표준품셈과 실투입 노무량을 조사하여 비교한 결과 다음과 같은 결과를 얻을 수 있었다. 실제 투입 노무량은 조적공 1.184인/천매, 미장공 0.048인/$m^2$, 방수공 0.039인/$m^2$, 타일공 0.059인/$m^2$이다. 표준품셈 대비 투입율은 보면 조적공 59.8%, 미장공41.3%, 방수공 31.5%, 타일공 34.3%이다. 방수공의 투입 비율이 가장 낮고 조적공이 비교적 높았다. 따라서 우리나라 공동주택 건설공사의 노무량은 실적공사비를 토대로한 원가계산이 바람직하지만, 공사관리에서 노무량이 주요 변수인 만큼 실제에 근접한 표준품셈을 지속적인 보완이 필요할 것으로 보인다.

• 전기의세계
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• 제14권4호
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• pp.8-17
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• 1965

Firstly, this study has analyzed the following factors affecting the optimum specifications and design of distributive transformers: 1. Facilities installation cost per unit power output. 2. Facilities operating & maintenance cost per unit power output. 3. Production cost per unit power output. 4. Load factor. 5. Loss factor. Secondly, it has clarified the relations between the following factors and the specifications and design of distributive transformers; 1. No-load loss., 2. Load loss., 3. Voltage regulation., 4. Exciting current. Finally, it has determined the method of the most economic design for the transformers using the above factors and relations, and, for optimum the illustrative purpose, suggested their optimum specifications, way of evaluation, and merits by means of typical example.

• 한국경영과학회지
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• 제14권2호
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• pp.67-74
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• 1989

This paper considers single-product production and inventory management problem where cumulative demands up to each time period are mutually independent random variables(known) having continuous probability distributions and the associated cost-minimizing production schedule (when to produce and how much to produce) need be determined in rolling horizon environment. For the problem, both the production cost and the inventory holding and backlogging costs are included in the whole system cost. The probability distributions of these costs are expressed in terms of random demands, and utilized to exploit a solution procedure for a production schedule which minimizes the expected unit time system cost and also reduces the probability of rist that, for the first-period of each production cycle (rolling horizon), the cost of the "production" option will exceed that of the "non-production" one. Numerical examples are presented for the solution procedure illustration.cedure illustration.