• International Journal of Aeronautical and Space Sciences
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• 제10권2호
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• pp.134-139
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• 2009

Various modules are generally combined with one another in order to perform rotorcraft preliminary design and its optimization. At the stage of the preliminary design, analysis fidelity is less important than the rapid assessment of a design is. Most of the previous researchers attempted to implement sophisticated applications in order to increase the fidelity of analysis, but the present paper focuses on a rapid assessment while keeping the similar level of fidelity. Each small-sized module will be controlled by an externally-operated global optimization module. Results from each module are automatically handled from one discipline to another which reduces the amount of computational effort and time greatly when compared with manual execution. Automatically handled process decreases computational cycle and time by factor of approximately two. Previous researchers and the rotorcraft industries developed their own integrated analysis for rotorcraft design task, such as HESCOMP, VASCOMP, and RWSIZE. When a specific mission profile is given to these programs, those will estimate the aircraft size, performance, rotor performance, component weight, and other aspects. Such results can become good sources for the supplemental analysis in terms of stability, handling qualities, and cost. If the results do not satisfy the stability criteria or other constraints, additional sizing processes may be used to re-evaluate rotorcraft size based on the result from stability analysis. Trade-off study can be conducted by connecting disciplines, and it is an important advantage in a preliminary design study. In this paper among the existing rotorcraft design programs, an adequate program is selected for a baseline of the design framework, and modularization strategy will be applied and further improvements for each module be pursued.

• 한국도로학회논문집
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• 제18권5호
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• pp.75-82
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• 2016

PURPOSES : This study was initiated to estimate the benefits from the campaign to prevent drowsy driving crashes on expressways. The study was conducted by the Korea Expressway Corporation using a contingent valuation method. METHODS : First, a questionnaire was designed for a preliminary survey. From the survey's results, the initial willingness to pay for the campaign was determined by averaging different amounts of payments chosen under virtual scenarios in the survey. The willingness to pay data was used to find a first bid price for the open-ended method used for the second survey. After that, a primary questionnaire was designed and conducted using a single dichotomous choice question (SDBCQ). Drivers at expressway resting areas were asked their willingness to pay for the campaign. Based on statistical analysis using data collected from the second survey, the mean willingness to pay was estimated using a probability utility function. Finally, the benefit from the campaign was calculated using the estimated willingness to pay and accident data on expressways. CONCLUSIONS : Based on the result from the contingent valuation method, the benefit from the campaign to prevent drowsy driving crashes was estimated to be 170.6 won per expressway trip. The benefit is to be paid as an additional toll. In addition, the traffic crash cost estimate is about 2,209,680,000 won less than the cost during the same period in 2014.

• 자원ㆍ환경경제연구
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• 제22권2호
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• pp.367-391
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• 2013

후쿠시마원자력발전소의 사고를 계기로 원전의 안전대책비용, 사고위험대응비용과 같은 외부비용들의 존재가 부각되고 있다. 이에 본 연구는 원전의 외부비용들 중에서 추가안전대책비용과 사고위험대응비용을 추정하고, 이를 발전원가 및 전기요금에 반영하여 변화정도를 살폈다. 원전의 추가안전대책비용은 70~90%의 이용률에서 0.53원/kWh~0.80원/kWh으로 원전의 발전원가에 큰 영향을 미치지는 않는다. 사고위험대응비용은 원전사고피해규모별, 사고발생빈도별, 이용률별로 0.0025원/kWh~26.4188원/kWh로 추정되었다. 사고위험대응비용을 포함시키면 원전발전원가는 47.58원/kWh~85.92원/kWh가 된다. 2011년을 기준으로 사고위험대응비용을 내부화한 경우의 전기요금의 증가율은 70~90%의 이용률에서 0.001%~10.0563% 로 추정되었다. 본 연구는 원전의 외부비용을 내부화하는 방법으로서 외부비용을 발전원가에 포함하여 전기요금에 반영하였다. 본 연구는 지금까지 우리나라에 논의되지 않았던 원전 외부비용을 내부화하는 방법의 하나가 될 것이다.

• 대한간호학회지
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• 제40권1호
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• pp.69-77
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• 2010

This methodological research was designed to develop performance evaluation key indicators (PEKIs) for management by objectives (MBO) and to estimate their weights for hospital nurses. Methods: The PEKIs were developed by selecting preliminary indicators from a literature review, examining content validity and identifying their level of importance. Data were collected from November 14, 2007 to February 18, 2008. Data set for importance of indicators was obtained from 464 nurses and weights of PEKIs domain was from 453 nurses, who worked for at least 2 yr in one of three hospitals. Data were analyzed using $X^2$-test, factor analysis, and the Analytical Hierarchy Process. Results: Based upon Content Validity Index of .8 or above, 61 indicators were selected from the 100 preliminary indicators. Finally, 40 PEKIs were developed from the 61 indicators, and categorized into 10 domains. The highest weight of the 10 domains was customer satisfaction, which was followed by patient education, direct nursing care, profit increase, safety management, improvement of nursing quality, completeness of nursing records, enhancing competence of nurses, indirect nursing care, and cost reduction, in that order. Conclusion: PEKIs and their weights can be utilized for impartial evaluation and MBO for hospital nurses. Further research to verify PEKIs would lead to successful implementation of MBO.

• 한국산업융합학회 논문집
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• 제24권6_2호
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• pp.861-872
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• 2021

An efficient cost management is important for the domestic social overhead capital(SOC) based on a long lifecycle after 30 years since completion. Maintenance in South Korea have had the restrictions of consistency and suitability of decision-making by the establishment of a budget plan based on the company estimate and repair and reinforcement methods determined by the inspection and diagnosis engineers' subjective determination for each facility. To resolve this issue, the Korea Institute of Civil Engineering and Building Technology is currently in development of a methodology to propose an optimum maintenance method according to the damage of components by artificial intelligence. This study has deduced the primary factors by analyzing information generated during bridge maintenance and management as a prior step for the development of technologies, and conducted a preliminary analysis to select the optimum artificial intelligence technology.

• 한국재난정보학회 논문집
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• 제8권4호
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• pp.319-327
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• 2012

본 연구는 대표적인 TMB 장비 회사인 독일 WRITH사에서 개발한 TMB 공법 적용 현장의 굴진보고서를 수집하여 작업운영 생산성을 분석하였다. 그리고 분석된 자료를 근거로 구경별(2.6m, 3.0m, 3.5m, 5.0m, 8.0m) 월굴진속도(m/월)를 도출하였다. 또한, 도출된 구경별 월 굴진속도를 근거로 독일의 WRITH사에서 구경별로 제시한 1m당 굴진에 소요되는 공사비 와 총공사기간을 산출하였다. 경암 40.0%, 연암 30.0%, 보통암 20%, 풍화암 10.0%로 구성된 암질을 기준으로 구경별로 도출된 월굴진속도, m당 공사비, 총공사기간은 향후 TBM 공법 적용시 기본계획단계와 기본설계단계에서 구경별 공사기간 및 공사비를 추정하는데 효과적인 활용 자료가 될 것으로 사료된다.

• 교육녹색환경연구
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• 제9권2호
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• pp.1-8
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• 2010

This study is to present an engineering solution for the repair frequency and repair rates of a building. The existing data for the repair frequency and repair rates are used to draw the probability distribution for the generalized repair frequency and repair rate in a building. The suggested methodology can be widely used for most buildings to estimate the legal repair frequency and repair rates. Also, the methodology can be applied to resolve the risks on the maintenance costs in LC (Life Cycle) plans or LCC (Life Cycle Cost) analysis. As the future studies, there are the multiple regression analysis including the parameters on incurred costs and the decision methods on efficient repair and replacement.

• 한국건설관리학회논문집
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• 제14권4호
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• pp.24-34
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• 2013

2004년부터 정부는 무분별한 저가입찰을 방지하고, 기술 경쟁에 의한 적정 시장 가격 반영 및 효율적인 계약관련 업무를 추진하는 것을 목적으로 실적공사비 제도를 도입 시행하고 있다. 하지만 실적공사비 제도의 도입이 낙찰단가 하락에 의한 정부의 예산 절감에만 기여할 뿐, 실질적인 시장가격을 반영하고 있지 못하고 있다는 우려의 목소리 또한 꾸준히 제기되고 있는 실정이다. 낙찰단가 하락에 의한 일반건설업체의 비용 부담은 전문건설업체로 전가되며 최종적으로 건설노동자의 피해로 이어질 가능성이 크기에, 실적공사비에 적정 가격을 반영하고 현실화하는 것은 성공적인 실적공사비 제도의 정착에 매우 중요한 요소이다. 따라서 본 연구는 노무비를 중심으로 노무중심공정을 도출하고 이들의 실적공사비단가와 해당 기능공의 시중노임단가를 비교하여 실적공사비의 현실화수준을 파악하고, 시계열분석을 통해 변화를 분석하고 예측하였다. 시장가격이 반영되지 않은 낙찰 단가의 실질적 하락은 노무 환경의 변화를 가속화하고, 임금체불, 업체부도 등 건설근로자의 직접적인 피해로 이어질 수 있기에 향후 본 연구가 현행 실적공사비 제도의 문제점을 해결하고, 개선방안을 수립하기 위한 기초 자료로 활용될 수 있을 것으로 기대된다.

• 한국전산구조공학회논문집
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• 제30권6호
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• pp.567-576
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• 2017

본 연구는 BIM 도입 효과를 극대화할 수 있는 현장 적용성 확보에 중점을 둔 철근콘크리트 골조공사의 BIM 견적모델 작성과 BIM기반 견적 업무 프로세스를 표준화한 가이드라인을 제시하는 것을 목적으로 한다. 이를 위하여 기존 지침 및 가이드라인의 BIM 견적모델 작성 범위 및 방식을 고찰하고, 철근콘크리트공사 수량산출 견적 지침 및 기준을 분석하며, 기존 견적 방식과 BIM기반 견적 방식에 대해 비교분석한다. 이를 통하여 BIM기반 견적 업무의 표준 프로세스를 수립하고, 콘크리트/거푸집/철근 견적모델의 작성 및 수량산출 기준을 도출하며, 철근콘크리트공사 BIM기반 수량산출 및 견적 업무의 성과물 목록 및 양식을 제시한다. 본 연구를 통해 작성된 BIM 견적 가이드라인은 BIM기반의 새로운 기술환경에 대한 진입장벽을 낮추고, 견적의 정확성 극대화를 통한 원가절감을 실현하며, BIM 업무와 건설산업의 생산성과 부가가치를 증대시켜, 궁극적으로 건설사업 전 생애주기에서 생산되는 정보를 통합 관리할 수 있는 기반을 구축하고 BIM 생태계를 조성하는데 기여할 것으로 기대한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.585-593
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• 2011

Actual fire test under a laboratory and fire simulation by using computer are considered into main methodology in order to estimate and predict fire size of railway train. Even if practical fire size could be obtained from the full-model railway car test such as a large scale cone-calorimeter test, it is not always possible and realistic due to that expensive cost and attendant dangers could in no way be negligible. In this point of view, fire simulation analysis method based on the computational fluid dynamics could be proposed as an alternative and it seems to be also efficient and reasonable. However, simulation results have to be verified and validated in accordance with the proper procedure including comparing analysis with the actual fire test. In this paper, fire load and growth aspect was investigated through the room corner test (ISO 9705) for the mock-up model of the actual railway car. Then, it was compared with the output data derived from the simulation by using Pyrolysis Model of the FDS (Fire Dynamics Simulator, by NIST) for the exact same domain and condition corresponding with pre-performed room-corner test. This preliminary verified and validated fire modeling method could enhance the reliability of output data derived from the fire simulation under the similar domain and condition.