• 한국농공학회논문집
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• 제49권6호
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• pp.93-101
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• 2007

In general, geotechnical properties have many uncertain aspects, thus probabilistic analysis have been used to consider these aspects. It is, however, quite difficult to select an appropriate target probability for a certain structure or construction process. In this study, minimum expected cost design method based on probabilistic analysis is suggested for design of vertical drains generally used to accelerate consolidation in soft clayey soils. A sensitivity analysis is performed to select the most important uncertain parameters for the design of vertical drains. Monte Carlo simulation is used in sensitivity analysis and probabilistic analysis. Total expected cost, defined as the sum of initial cost and expected additive cost, varies widely with variation of input parameters used in design of vertical drain systems. And probability of failure to get the minimum total expected cost varies under the different design conditions. A minimum value of total expected cost is suggested as a design value in this study. The proposed design concept is applicable to unit construction process because this approach is to consider the uncertainties using probabilistic analysis and uncertainties of geotechnical properties.

• KIEAE Journal
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• 제6권1호
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• pp.3-10
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• 2006

As has been expected, economic factors are a major consideration in almost every decision in building design process. Assuming that improving a lighting system, existing or proposed, will reduce operating cost, what preliminary economic guidelines can be established to determine whether any proposed investment appears cost effective? In such a case a reasonable technique to compare system costs is by life-cycle costing. Stated simply, a life-cycle cost represents the total cost of a system over its entire life cycle, that is, the sum of first cost and all future costs. This paper aims to exemplify the benefit of daylighting in term of economic consideration. Four different electric lighting system designs are proposed and a lighting control system that is continuously operating according to the level of daylight in the space has been adapted. The accumulated performance of electric and daylighting is figured out to declare the effective depth of daylight in the space. The analysis on the saving amount of lighting energy due to daylight has been undertaken in answer to the question, that is, several projects are being considered, which is the most desirable from the cost-effectiveness viewpoint. The result shows clearly that although denser layout of lighting fixtures might be more effective to interface to the level of daylight ceaselessly changeable, its economic benefit may not meet the expected criterion the reason of increased initial investment and maintenance cost for the fixtures and control hardware.

• 한국BIM학회 논문집
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• 제7권2호
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• pp.16-24
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• 2017

It is very important to estimate accurate construction total cost needed early in the project. In the initial phase of the design, the project cost estimates are determined by total quantity from design documents and the variables that affect the calculation of the total cost of the project. In order to determine accurate total construction cost, the contractor has to produce detailed quantity information based on the drawings and specifications. The process of preparing quantification and cost estimation documents is still being worked out manually, and a lot of errors have been occurred in many cases. Recent advances in information technology have led to the BIM based quantity takeoff and cost estimation. However, there are some limits to the extent to which the current specifications for BoQ documents are computed from BIM model. This research analyze the current BoQ cases and analyze how to make quantity takeoff possible through BIM. The study defined five levels of quantity category that could be produced by BIM. Only about 40% or indirectly usable items can be used when information is extracted to BIM modelling. This is very insufficient to fill out the BoQ. The BoQ document structure quantity takeoff specifications should be simplified in order to BIM based cost estimation more efficiently.

• 대한건축학회논문집:구조계
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• 제34권2호
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• pp.41-48
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• 2018

Carbonation is one of the major detrimental factors to the reinforced concrete structures owing to penetration of atmospheric CO2 through the micro pores, thereby it reduces the durability of the concrete. The maintenance periods and cost for concrete according to the coefficient variation of different finishing materials is documented in literature. However, it is required to carry out the systematic and well planned studies. Therefore, keeping them in mind, surface repair was carried out to the carbonated concrete and the maintenance cost was calculated to measure the durability life after repair with different variable. The deterministic and probabilistic methods were applied for durability and repair cost of the concrete. In the existing deterministic model, the cost of repair materials increases significantly when the concrete structure reaches its service life. In present study using a stochastic model, the maintenance period and cost was evaluated. According to obtained results, there was no significant difference in the number of maintenance of the coefficient variation. The initial durability has a great influence on the maintenance time and cost of the structure. Unlike the deterministic model, the probabilistic cost estimating model reduces the number of maintenance to the target service life expectancy.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.119-129
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• 2007

In January 2005, the BTL private investment project was introduced in the Korean construction market as part of the plan to provide high-quality public service and expand the required facilities in a timely manner. Nonetheless, problems such as the low earning rate at the beginning of the business, burden of service compared to the cost of the proposed business, and limitations of the local small and medium-sized companies in relation to their participation in the project arose. The LCC analysis system for the BTL projects was developed as part of efforts toward efficiently investigating the investment eligibility. Specifically, methods for LCC analysis were selected for each stage of the BTL project in relation to the requests of experts for military residential facilities and public educational facilities. Variables were then extracted to derive an accurate analysis value, LCC for the 5 cost items (initial investment cost, operating expenses, maintenance expenses, energy cost, and disposal cost), analyzed, and system enabling comparative analysis for single and multiple initiatives by year and item, developed. Thus, we have to clearly require the accumulation of data to examine the appropriateness of the results of LCC analysis based on data and results.

• 한국도로학회논문집
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• 제13권4호
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• pp.167-175
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• 2011

효율적인 도로의 설계와 관리를 위해서는 도로건설의 경제성 분석이 중요하며 이를 위해서는 도로 상태별 차량별 유류소모량의 평가가 필요하다. 도로에서는 초기 건설비용, 유지보수비용, 차량운행비용, 지정체비용 등이 발생되는데, 도로의 경제성 분석을 위해서는 초기 건설비용, 유지보수비용 등과 같은 관리자비용과 차량운행비용, 지정체비용 등과 같은 이용자비용을 모두 포함한 사회적 비용이 고려되어야 한다. 이 중 차량운행비용은 교통량에 따라 그 비용이 변화되므로 차량운행비용 항목의 큰 부분을 차지하는 유류소모량 또한 교통량에 따라 변화하게 된다. 그런데 유류소모량은 차량의 주행속도 및 도로포장의 상태, 특히 평탄성에 따라 크게 변화되므로 도로의 경제성 분석을 위한 차량운행비용의 산정을 위해서는 주행차량에 대해 도로 상태에 따른 유류소모량을 평가하여 경제성 분석에 반영해야 할 필요가 있으나 아직 이를 고려하지 못하고 있는 상황이다. 본 연구에서는 국내에서 운행되는 승용차에 대해서 도로 상태별 유류소모량 추정모델을 개발하였다. 우선 우리나라의 교통시설 투자평가 및 도로건설의 예비타당성 조사에서 차량운행비용 산정을 위해 사용되고 있는 주행속도와 유류소모량의 관계식을 고찰하고, 승용차를 대상으로 도로포장의 평탄성에 따른 유류소모량 변화의 관계를 실제 도로에서 실측하여 평탄성과 유류소모량 변화의 관계를 분석하였다. 실험 결과, 평탄성에 따른 유류소모량의 변화는 평탄성이 1m/km 증가하였을 경우 100km 주행시 약 $80m{\ell}$ 정도의 비율로 유류소모량이 증가하는 것으로 확인되었다. 따라서 도로의 설계 및 유지관리에 있어서 보다 정확한 경제성 분석을 수행하기 위해서는 도로포장의 평탄성에 따른 유류소모량 변화를 고려해야 할 필요가 있다.

• 대한영양사협회학술지
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• 제9권2호
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• pp.128-137
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• 2003

The purposes of this study were to investigate the current status of contracted hospital food services and to find out the difference in accordance with the number of beds in hospitals. Thirty six hospitals having more than 100beds in Seoul, Inchon and Kyungkido were the subjects of this study. Data was collected through surveys. The survey was conducted during March and April in 2002. The Questionnaires were mailed to the 36 directors of dietetic departments of the hospitals and 36 managers of contracting patient food services. Statistical analysis was completed using SPSS Win(11.0) for descriptive analysis and t-test. The results of the study are summerized as follows; Ⅰ. Hospital perspective : The range covered by contract food service was 63.3% and 36.7% in hospital food services, and medical nutrition services. The patient and employee food services were in 83.3%, and patient food services were in 6.7%. The methods selecting contractors are general, limited, selected and competitive biddings, and private contracts. The responsibility for supervision of contract food services was the dietetic department (51.7%) in most cases. Hospitals having personnel responsible for contracting affairs were in 75.9% of the cases and 24.1% did not have personnel. The biggest reason for contracting was facilitation of personnel management. The most important criteria on selecting food services contractors was the professionality of the contractor. Ⅱ. Contractor's perspective : The cost per meal in the year 2001 was composed of 1,905 won for food cost, 1,081 won for labor cost, 222 won for expenses, 114 won for VAT, 14 won for rent and 146 won for miscellaneous or controllable expense, representing 109 won loss per meal. The profit-and-loss contract cost is higher than the fee-contract cost. The ratios of food cost, labor cost and expenses are higher and the ratios of miscellaneous or controllable expense, VAT, rent and profit are lower in hospitals with more than 400 beds compared with those less than 400 beds. However, no significant differences are present between these two groups of hospitals. The actual contract period was 2.2 years upon initial contract and 1.2 years upon renewal. The initial investment cost was 53 million won and the cost of renovation and repair was 8.5 million won. Significant differences were present between two groups of hospitals. The conditions of employment and number of personnel hired by contractors for contract patient food services were significantly different according to the number of beds.

• 산업경영시스템학회지
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• 제19권40호
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• pp.233-240
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• 1996

A fixed amount compensator is proposed for a process with a linear tool wear function. A Cost model is constructed which involve process adjustment cost and quality loss. Symmetric and asymmetric quadratic functions of the deviation of a quality measurement from the nominal target value are considered as the quality loss functions. Methods of finding optimal values of initial setting and compensation limit are presented and a numerical example is given.

• Architectural research
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• 제7권2호
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• pp.61-68
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• 2005

A methodology for design of reinforced concrete members for serviceability in general and deflection control in particular is presented based on application of utility theory. The approach is based on minimizing total cost including both initial construction and cost of failure considering variability in structural behavior and various forms of serviceability loss function. The method is demonstrated for the case of a simply supported slab for example.

• 산업공학
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• 제6권1호
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• pp.87-97
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• 1993

In this paper, the plant layout planning is optimized at the K-area of the K-airline. The K-area includes 15 activies. The initial solution is found qualitatively by designing a space relationship diagram for the relationship. The cost of material handling is minimized by finding the final layout plan using CRAFT. In comparing to the master plan of K-airline, the final layout plan in this research can reduce the cost of material handling by 52%.