• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.375-378
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• 2020

본 연구는 토지 보상비의 추정 모델 개발을 위해서 건설 CALS (Continuous Acquisition & Life-cycle Support) 시스템의 내부데이터와 개별공시지가 및 표준지 공시지가 등의 외부데이터, 그리고 개발된 추정 모델의 고도화를 위한 개별공시가 데이터를 기반으로 생성된 데이터를 활용하였다. 이렇게 수집된 3가지 유형의 데이터를 분석하기 위해서 기존 선형 모델 또는 의사결정나무 (Tree) 기반의 모델상 과적합 오류를 제거할 경우 매우 유용한 알고리즘으로 Decision Tree 기반의 Xgboost 알고리즘을 데이터 분석 방법론으로 토지 보상비 추정 모델 개발에 활용하였다. Xgboost 알고리즘의 고도화를 위해 하이퍼파라미터 튜닝을 적용한 결과, 실제 보상비와 개발된 보상비 추정 모델의 MAPE(Mean Absolute Percentage Error) 범위는 19.5%로 확인하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.153-153
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• 2010

The world is moving towards a post-carbon society and needs clean and renewable energy for sustainable development. There are many methodological approaches which are helping this shift based on analyzed data about energy resources and which focus on limited types of energy including liquid fossil, solid fossil, gaseous fossil, and biomass (e.g. IPCC Guidelines, ISO 14064-1, WRI Protocol, etc.). We should also consider environmental impact (e.g. greenhouse gas emissions, water use, etc.) and the economic cost of the renewable energy to make a better decision. Recently, researchers have addressed the environmental impact of new technologies which include photovoltaics, wind turbines, hydroelectric power, and biofuel. In this work, we analyze the environmental impact with a carbon emission factor to present a correlation between $CO_2$ emission and the cost of energy resources standardized by the energy output. In addition, we reviewed Life Cycle Assessment (LCA) as another methodology. Researchers who are studying energy systems have ignored the impacts of entire energy systems, e.g. the extraction and processing of fossil fuels. In power sector, the assessment should include extraction, processing, and transportation of fuels, building of power plants, production of electricity, and waste disposal. Therefore LCA could be more suitable tool for energy cost and environmental impact estimation.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.150-156
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• 2004

Though the concept of Life-Cycle Cost (LCC) itself is not new, its effectiveness for planning, design, rehabilitation and maintenance/management of civil infrastructures is becoming increasingly recognized. For the decision problems as in the case of the LCC of plant facilities, equipments, bridge decks, pavements, etc., the Life-Cycle Cost Analysis (LCCA) is relatively simple, and thus its practical implementation is rather straightforward. However, when it comes to major infrastructures such as bridge, tunnels, underground facilities, etc., the LCCA problem becomes extremely complex because lack of cost data associated with various direct and indirect losses, and the absence of uncertainty data available for the assessment as well. As a result, the LCC studies have been largely limited only to those relatively simple LCCA problems of planning or conceptual design for making decisions. Accordingly, in the recent years, the researchers have pursued extensive studies on the LCC effectiveness mostly related to LCC models and frameworks for civil infrastructures. Moreover, recently the demand on the practical application of LCC effective decisions in design and maintenance is rapidly growing unprecedently in civil engineering practice. Indirction cost is very important on LCC formulation. But that is very difficult and complicate the estimation every LCC. The objective of this paper is to suggest efficient regression model for the estimation of indirect cost approach to the practical application of LCC for the design and rehabilitation of civil. infrastructures considering traffic, traffic network, detour condition, and workzone condition. In this paper, it performed the sensitivity analysis and correlation analysis of parameter for development of regression model of inflection cost.

• International Journal of High-Rise Buildings
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• v.10 no.1
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• pp.29-34
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• 2021

Vertical greenery has become an important technological means to improve the ecological environment condition in urban high-density areas, especially in central areas of Chinese cities. The cost of vertical greenery has significantly increased both in the decision-making process of architectural design and in the assessment of the sustainability potential of urban complexes. The estimation and evaluation of the cost of vertical greenery have become important obstacles to multi-party investment in the construction of vertical greenery. Considering the factors of the building typology and full life-cycle cost, this paper constructs an assessment model of vertical greenery in seven types in urban complex, and suggests an optimized approach to vertical greenery in an urban complex.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.162-163
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• 2014

Operation and maintenance stage consists the largest portion of project life cycle cost. Appropriate management and analysis of such stages have massive effect on the total project cost. The effective prediction of optimized repair period is one of main factors in ㅌ management. However, it has been analyzed that the prediction of appropriate repair period revealed limitations in reliability. Therefore, this study suggests a methodology of repair period prediction by dividing finished projects into similar groups with same properties to be compared with the target project using quantitative variables.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.394-399
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• 2009

Since some decades ago, there has been a concern for resource depletion and environmental pollution associated with building properties. In addressing such impact of the built environment, there is a recognition of the existence of alternative building materials, fuels for energy supply as well as technologies for waste handling and disposal. Nevertheless, for long time, the choice between such alternatives was dictated by factors such as differences in prices and aesthetic values. A new important dimension in discriminating between different options is the environmental dimension. This aspect is important since buildings are one of the spatially big new additions to the natural environment that consume a lot of materials and energy during their long lifetime. Thus, with the environmental dimension kept in mind, a existing cost estimation needs to be changed. A new cost assessment method, Life Cycle Cost, should calculate overall costs with dimensional factors: investment and utility costs as well as maintenance costs over the lifetime of the building. Aiming to give an overview of the present status of Building Life Cycle Assessment(LCA) tools as a basis for further research and development including economic performance, this paper describes and compares 3 different tools for Life Cycle Assessment(LCA) and economic analysis of the green buildings. This paper compared these approaches based on various aspects. These include economic analysis method, evaluation duration, data of results(index). Use of the comparison analysis is to produce a better picture and indicate profits and shortcomings for the tools as a group; thus providing important direction improvement of LCA tool as well as further research and development of this group of tools.

• Journal of Applied Reliability
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• v.16 no.4
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• pp.280-286
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• 2016

Purpose: Recently, Jiang defines the tradeoff B life to minimize a sum of life lost by preventive maintenance (PM) and corrective maintenance (CM) contribution parts and sets up an optimal replacement age of age replacement policy as this tradeoff life. In this paper, Jiang's model only considering the known lifetime distribution is extended by assigning different weights to two parts of PM and CM in order to reflect the practical maintenance situations in application. Methods: The new age replacement model is formulated and the meaning of a weight factor is expressed with the implied cost of failure under asymptotic expected cost model and also discussed with one-cycle expected cost criterion. Results: The proposed model is applied to Weibull and lognormal lifetime distributions and optimum PM replacement ages are derived with corresponding implied cost of failure. Conclusion: The new age replacement policy to escape the estimation of cost of failure in classical asymptotic expected cost criterion based on the renewal process is provided.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.469-472
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• 2003

A life cycle cost analysis model for public water supply systems should be different from the ones for other civil and architectural facilities as the operation and the maintenance cost of the water supply systems mainly come from the various mechanical systems and the pipeline systems of the collecting/treating/distributing facilities. This paper presents a cost classification scheme and a life cycle cost analysis model for public water supply systems. A value analysis (VA) procedure that is well suited for practical purposes is also presented. The presented life cycle model and the value analysis procedure were applied to a real world project, and this case study is discussed in the paper. The model and the procedure presented in this study can greatly contribute to the value-oriented design alternative selection, the estimation of the maintenance cost, and the allocation of budget for water supply system construction projects.

• Korean Journal of Construction Engineering and Management
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• v.5 no.2 s.18
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• pp.181-193
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• 2004

A life cycle cost analysis model for public water supply systems should be different from the ones for other civil and architectural facilities as the operation and the maintenance cost of the water supply systems mainly come from the various mechanical systems and the pipeline systems of the collecting/treating/distributing facilities. This paper presents a cost classification scheme and a probabilistic life cycle cost analysis (PLCCA) model for public water supply systems. A value analysis (VA) procedure that is well suited for practical purposes is also presented. The presented probabilistic life cycle model and the value analysis procedure were applied to a real world project, and this case study is discussed in the paper. The model and the procedure presented in this study can greatly contribute to the value-oriented design alternative selection, the estimation of the maintenance cost, and the allocation of budget for water supply system construction projects.

• The Journal of Society for e-Business Studies
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• v.15 no.1
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• pp.139-155
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• 2010

The purpose of this paper is to develop a framework of software cost estimation guidelines and to derive a mid-long term direction for development of the software cost estimation guidelines. In this paper, all the steps in the software life cycle are researched in the view of cost estimation, and current software cost estimation guidelines and models have been reviewed and analysed first. Second, a plan to separate unit cost per function point from standard procedure in current software cost estimation guidelines is presented to strengthen maket self-regulating function as a mid-long term developmental direction for software cost estimation guidelines. Third, construction of cost repository, making standard procedure for software cost estimation guidelines, development of various kinds of software cost estimation models, and a system for experts on software cost estimation are presented as the prerequisites for the future model framework of software cost estimation guidelines. Finally a roadmap for establishing the future model is proposed.