• 한국건축시공학회지
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• 제21권2호
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• pp.105-112
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• 2021

국내 해체시장 규모는 꾸준히 증가되고 있는 반면, 해체공사비 예측 연구는 미흡한 실정이다. 이에 본 연구에서는 해체공사비 변동에 영향을 미치는 다양한 속성을 반영한 공사비 예측 모델을 제시하고자 하였다. 이를 위하여 기존 문헌고찰과 전문가 자문을 바탕으로 13개의 영향요인과 실적공사비 데이터를 수집하였으며, 회귀분석을 통해 2개의 예측모델을 구축하고 예측정확도를 평가하였다. 그 결과, 약 6~12%의 평균 오차율을 보였으며, 예측 모델로서의 활용 가능성을 모색할 수 있었다. 본 연구 결과는 향후 국내 해체공사의 적정 공사비산정 및 관련 기준 정비에 기여할 수 있을 것이다.

• 한국도로학회논문집
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• 제19권4호
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• pp.9-18
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• 2017

PURPOSES : This study evaluates the reasonableness of the recommended amount of deicing chemicals based on historical data for snow removal. The result can be used to aid decision-making for the reservation of cost-effective de-icing chemicals. METHODS : First, the recommended amount of de-icing chemical to use and historical usage data were evaluated to identify specific usage characteristics for each region. Road maintenance length and snow-removal working days were analyzed over the past five winter seasons. Next, differences in the recommended amount of chemical to use and actual use were compared using the Kolmogorov-Smirnov test. Last, the two types of data were analyzed using a chi-square test to verify if the two distributions of variation pattern are statistically significant. We found that there are significant differences between the data from each region during the past five winter seasons. RESULTS : The results showed that the equation for calculating the amount of de-icing chemical to use appears to be revised. CONCLUSIONS : The results imply that the equation for calculating the amount of de-icing chemical to apply as a national standard is very important when the public agency makes decisions related to snow-removal.

• 한국산학기술학회논문지
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• 제17권11호
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• pp.128-134
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• 2016

교량관리시스템(Bridge Management System, BMS)을 활용한 교량의 생애주기 관리를 위해서는 교량의 부재별 보수보강 비용 산정이 필수적이다. 본 연구에서는 BMS에 적용 가능한 체계적인 유지관리 비용 모델의 개발을 위하여 교량을 구성하는 대표 부재를 정의하고, 대표 부재별 세부 및 대표 보수보강 공법을 도출하였다. 세부 보수보강 공법별 단가를 산정하기 위해 표준 품셈과 실적 공사비를 이용해 각 세부 보수보강 공법별 일위대가를 구성하고, 적산 프로그램을 활용하여 보수보강 단가의 갱신이 용이하도록 체계적인 절차를 제시하였다. 또한 세부 보수보강 공법별 단가와 적용 빈도를 고려해 가중 평균 형태로 대표 보수보강 공법의 평균 단가를 산정하였다. 도출된 평균 단가를 기존의 실적 비용 단가와 비교 검증하여 적정성을 검토하였다. 제안된 평균 보수보강 비용 단가는 교량 유지관리 계획 수립 단계에서 요구 예산의 타당성을 검증하거나 보수보강 실적 비용의 적정성을 검토하는 데 활용될 수 있다. 본 연구를 통해 유지관리 비용 정보의 신뢰도와 의사결정의 합리성을 증진시킬 수 있을 것으로 판단된다.

• Industrial Engineering and Management Systems
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• 제15권4호
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• pp.403-431
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• 2016

The objective of this study is to integrate the business, maintenance and production processes of a manufacturing system by incorporating errors. First, the required functions are estimated according to the historical data. The system activities are simulated by Visual SLAM software and the required outputs are obtained. Several outputs including lead times in different dimensions, total cost and production rates are computed through simulation. Finally, data envelopment analysis (DEA) is utilized in order to select the best option between the defined scenarios due to the multi-criteria feature of the problem. This is the first study in which the lead times, cost and production rates are simultaneously considered in the integrated system imposed of business, maintenance and production processes by incorporating errors. In the current study, the major bottlenecks of the system being studied are identified and suggested different strategies to improve the system and make the best decision.

• Membrane and Water Treatment
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• 제8권2호
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• pp.137-147
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• 2017

A water treatment utility in South Korea operates a large system of pressurized hollow fiber membrane (PHFM) modules. The optimal selection of membrane module for the full scale plant was critical issue and carried out using Risk-based Life Cycle Cost (RbLCC) analysis based on the historical data of operation and maintenance. The RbLCC analysis was used in the process of decision-making for replacing aged modules. The initial purchasing cost and the value at risk during operation were considered together. The failure of modules occurs stochastically depending on the physical deterioration with usage over time. The life span of module was used as a factor for the failure of Poisson's probability model, which was used to obtain the probability of failure during the operation. The RbLCC was calculated by combining the initial cost and the value at risk without its warranty term. Additionally, the properties of membrane were considered to select the optimum product. Results showed that the module's life span in the system was ten years (120 month) with safety factor. The optimum product was selected from six candidates membrane for a full scale water treatment facility. This method could be used to make the optimum and rational decision for the operation of membrane water purification facility.

• 산업경영시스템학회지
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• 제45권3호
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• pp.18-30
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• 2022

Predicting remaining useful life (RUL) becomes significant to implement prognostics and health management of industrial systems. The relevant studies have contributed to creating RUL prediction models and validating their acceptable performance; however, they are confined to drive reasonable preventive maintenance strategies derived from and connected with such predictive models. This paper proposes a data-driven preventive maintenance method that predicts RUL of industrial systems and determines the optimal replacement time intervals to lead to cost minimization in preventive maintenance. The proposed method comprises: (1) generating RUL prediction models through learning historical process data by using machine learning techniques including random forest and extreme gradient boosting, and (2) applying the system failure time derived from the RUL prediction models to the Weibull distribution-based minimum-repair block replacement model for finding the cost-optimal block replacement time. The paper includes a case study to demonstrate the feasibility of the proposed method using an open dataset, wherein sensor data are generated and recorded from turbofan engine systems.

• 한국건축시공학회지
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• 제6권3호
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• pp.115-122
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• 2006

This study is aimed to get clear model for CM fee level in public construction project. For the practical use and main target, CM for fee contract only is assessed and analysed. Cost estimate by percentage of total contract sum and method based on the historical construction data have significant deficiency. An regression model and probabilistic model are suggested with 9 independent variables. In the case of limited work scope, an element based floor area model is suggested and concluded with fish-bone scheme.

• 대한토목학회논문집
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• 제31권4D호
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• pp.595-601
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• 2011

고속철도 기본계획단계에서 노반공사의 토공사 공사비 추정은 단위길이당 공사비(원/km)를 활용하고 있다. 이 단가는 과거자료를 기준으로 한 산술평균으로 오차가 클 수 있으며, 기본설계 단계 등 다음단계의 견적과 연계성이 부족한 단점이 있다. 본 연구는 철도연장에 토공사의 기술적 특성인 지질조건을 추가하는 매개변수 기반 개략공사비 산정모델을 제시한다. 데이터분석은 회귀분석법을 적용하였으며, 독립변수는 길이, 지질(토사, 풍화암, 연암, 경암) 구성 비율이고, 36개 공구 실적공사비를 참조하였다. 개발된 모델은 실적공사비와 비교한 결과 -0.4% ~ +31% 범위로 나타나, 전형적 범위인 -30% ~ +50% 이내이므로 유효한 것으로 판정한다. 본 모델은 공사비 영향의 주요요인인 길이에 기술적 특성인 지질요건을 추가함으로써 공사비 산정결과의 신뢰도 향상을 꾀함으로써 단계별 효과적 총사업비관리, 재정지출 감소 및 사업의 경제성 확보에 기여할 수 있을 것으로 기대된다.

• 한국조경학회지
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• 제25권1호
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• pp.82-99
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• 1997

The purpose of this study is to establish work classification system of landscape construction in order to offer the basis of new estimation system of public landscape construction. New estimation system is based on historical construction data. For application of this system, the standard work classification system is necessary. Because extensive cost data should be accumulated under an unified construction work classification system. In the study of new estimation system carried by KICT(Korea Institute of Construction Technology), landscaping works belong to earth work of civil engineering. It looks very unreasonable work classification, because landscape archtecture has its own specialties and professional domain. In this study, information classification systems in the construction industry and various landscaping works of housing developments are analysed. As a result. a standard work classification system of housing landscape construction is proposed in section VI-3. This standard work classification structure consists of three levels divisions (i.e large work division, middle work division, small work division) . Now in this study, housing landscape construction works are divided into four large works and twenty six middle works. According to work attributes, middle and small work division is possible to subdivide into details.

• 대한전기학회논문지:전력기술부문A
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• 제52권12호
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• pp.705-712
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• 2003

In this paper, we propose new unified methodologies of reliability and its cost evaluation in power distribution systems. The unified method means that the proposed reliability approaches consider both conventional evaluation factor, i.e. sustained interruptions and additional ones, i.e. momentary interruptions and voltage sags. Because the three voltage quality phenomena generally originate from the outages on distribution systems, the basic and additional reliability indices are summarized considering the fault clearing mechanism. The proposed unified method is divided into the reliability evaluation for calculating the reliability indices and reliability cost evaluation for assessing the damage of customer. The analytic and probabilistic methodologies are presented for each unified reliability and its cost evaluation. The time sequential Monte Carlo technique is used for the probabilistic method. The proposed DVL(Demand Varying Load) model is added to the reliability cost evaluation substituting the average load model. The proposed methods are tested using the modified RBTS(Roy Billinton Test System) form and historical reliability data of KEPCO(Korea Electric Power Corporation) system. The daily load profile of the each customer type in domestic are gathered for the DVL model. Through the case studies, it is verified that the proposed methods can be effectively applied to the distribution systems for more detail reliability assessment than conventional approaches.