• Journal of the Korea Concrete Institute
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• v.20 no.1
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• pp.13-22
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• 2008

The initiation and growth processes of cyclic ice body in porous systems are affected by the thermo-physical and mass transport properties, as well as gradients of temperature and chemical potentials. Furthermore, the diffusivity of deicing chemicals shows significantly higher value under cyclic freeze-thaw conditions. Consequently, the disintegration of concrete structures is aggravated at marine environments, higher altitudes, and northern areas. However, the properties of cyclic freeze-thaw with crack growth and the deterioration by the accumulated damages are hard to identify in tests. In order to predict the accumulated damages by cyclic freeze-thaw, a regression analysis by the response surface method (RSM) is used. The important parameters for cyclic freeze-thawdeterioration of concrete structures, such as water to cement ratio, entrained air pores, and the number of cycles of freezing and thawing, are used to compose the limit state function. The regression equation fitted to the important deterioration criteria, such as accumulated plastic deformation, relative dynamic modulus, or equivalent plastic deformations, were used as the probabilistic evaluations of performance for the degraded structural resistance. The predicted results of relative dynamic modulus and residual strains after 300 cycles of freeze-thaw show very good agreements with the experimental results. The RSM result can be used to predict the probability of occurrence for designer specified critical values. Therefore, it is possible to evaluate the life cycle management of concrete structures considering the accumulated damages due to the cyclic freeze-thaw using the proposed prediction method.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.7 no.1
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• pp.23-31
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• 2011

The objectives of this study are to analyze the performance of a heat pump system with the various heat source and to carry out economic assessment for the heat pump system. The COP of the river water and ground source heat pump system was 20% higher than that of the air source heat pump system because river water and geothermal provide stable operating temperature compared with air temperature throughout the year. In addition, the economic assessment of a heat pump system using air, river water, and geothermal as a heat source was carried out. The ratio of the life cycle operating cost to the life cycle cost increased with the increase of building capacity. The payback period was found to be less than 3.3 and 4.5 years, respectively when the capacity of the river water and ground source heat pump was larger than 10 RT.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.839-842
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• 2008

Construction VE is the system introduced in order to reduce the life cycle cost and promote the performance of construction facilities, used in architecture and civil construction since apply to construction over 10 billion from december 2005. But yet it is short of VE specialist and it is not a purpose in maximization of value creation through VE but strong better awareness of tool for budget reduce. This study tries to contribute to qualitative advance of design VE by analyze substantial degree of VE Procedure and VE result by Job Plan used widely in domestic an object design VE competition case to crossroad.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.656-661
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• 2009

상수도시설은 준공후 관련지자체에 이관 관리하는 시설로서 사용관종이 현재 다양하게 생산 보급되고 있어 관종 선정시 다각적인 측면에서 검토하여 채택하여야 한다. 최근 한국토지공사에서 사용하고 있는 상수도 관종은 대부분 택지개발계획 등 인허가 당시부터 관리주체인 지방자치단체 등과의 협의과정을 거쳐 선정되는 경우가 많아 자재선택에 한계성이 있다. 이를 극복하기 위해서는 자재 성능에 대한 공사내 명확한 기준이 제시되어야 한다. 상수관종을 선정하기 위한 가장 중요한 요소는 경제성으로 판단되는데, 관종의 경제성은 시공비와 자재비를 포함한 단순 공사비에만 국한되는 것이 아니라 유지관리비용을 포함한 생애주기비용(LCC: Life Cycle Cost)을 평가하여야 한다. 따라서 본 연구에서는 한국토지공사에서 택지지구 조성을 위해 사용한 배수관.급수관용 상수관종에 대한 경제성 평가기준을 제시하였고, 평가기준에 따라 각각의 택지지구 조성사례별로 종합적인 경제성 평가를 수행하였다. 보다 풍부한 자료를 바탕으로 객관적인 경제성평가 기준을 수립하기 위한 전(前)과정으로 이해되길 바라며, 설계시부터 객관적인 평가기준을 통해 합리적인 상수관을 선정하여 지금까지의 상수관종 자재선택의 한계를 최소한으로 축소하고자 하는데 가장 큰 목표를 가지고 있다.

• The Journal of Sustainable Design and Educational Environment Research
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• v.12 no.1
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• pp.25-34
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• 2013

As the construction industry develops, environmental pollution gets increasingly serious, giving damage including the increase of incidence of respiratory diseases and skin diseases among children with weakened immune systems, rather than adults. In daycare centers, infants and children spending much of their time, have high frequency of contact with the interior floor finish material. However, the majority of the child care centers don not use eco-friendly flooring but ordinary monorium flooring, because the initial investment cost of the eco-friendly flooring is higher than ordinary monorium flooring. Therefore, in this study, life cycle costs including the initial investment cost of the eco-friendly flooring and ordinary monorium flooring were calculated, demonstrating that the eco-friendly flooring is more economical than ordinary monorium flooring in terms of life-cycle cost. In addition, the analysis of the environmental performance also showed the excellence of the eco-friendly floor finishes. It is expected that the use of the eco-friendly floor finishes will increase due to their excellence in the aspect of life cycle cost and eco-friendly performance, through this study.

• Land and Housing Review
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• v.10 no.4
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• pp.51-59
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• 2019

The government is encouraging the notice of obligatory reclaimed asphalt as a result of the economic and social positioning of green growth to reduce the amount of waste resources and to solve natural resource problems by recycling continuously generated waste resources. However, it is necessary to develop application guideline for each application to apply reclaimed asphalt to the site because quality control of the reclaimed asphalt is difficult and the specifications are ambiguous as well. Therefore, in this study, the mix design, quality test, performance test, and finite element analysis about reclaimed Asphalt Pavement were conducted to develop application guideline for reclaimed hot asphalt. The mix design was carried out for the comparative general hot mix asphalt mixture, the reclaimed hot mix asphalt mixture using the additive, and the reclaimed hot mix asphalt mixture without the additive. Indirect tensile strength and tensile strength ratio tests were used to characterize the reclaimed hot mix asphalt mixture. Using the results of dynamic modulus test and FWD test for KPRP analysis and finite element analysis, the performance life was evaluated for general pavement and pavement using recycled aggregate. Finally, the life cycle cost analysis was used to compare and analyze the economics of reclaimed asphalt concrete pavement.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.5
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• pp.212-217
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• 2014

Recently, the use of renewable energy has been increased due to growing concern on the energy-saving at buildings and the reduction of $CO_2$ emission. In the field of architecture, to reduce the energy consumption of heating, cooling and hot water supply, heat pump systems with renewable energy has been developed and used in various applications. However, there have been many of researches on the large-scale commercial heat pump systems, but the research and the field application of a compact heat pump system is rare. Therefore, in order to develop the compact heat pump for the small-scale residential building, this study conducted the performance test and feasibility study for a hybrid heat pump using the heat source of air, solar and ground. In the results of experiments through a trial product, the average COP of cooling mode with ground heat source was 4.75, and it of heating mode was 4.03. Furthermore, the average COP of cooling mode with air heat source was 2.60, and it of heating mode was 2.92. Finally, payback period of the system was calculated as 9.2 years.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.11
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• pp.621-628
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• 2009

The objectives of this study are to analyze the performance of a river water-source heat pump and to carry out economic assessment for the heat pump. The COP of the river water-source heat pump was 3-21% higher than that of the air-source heat pump because river water provides stable operating temperature compared with air temperature throughout the year. The economic analysis was carried out by comparing the initial and operating cost of the river water-source heat pump with those of the conventional air-source heat pump. The ratio of the life cycle operating cost to the life cycle cost increased with the increase of building capacity. The payback period was found to be less than 3.5 years when the capacity of the river water-source heat pump was larger than 10 RT.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.12
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• pp.181-188
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• 2019

The maintenance of school building is pivotal issue. However, it is difficult to obtain basic analysis data for LCC(Lifecycle Cost) analysis and maintenance planning of school building. Therefore, this study proposed System Dynamics(SD) techniques to make maintenance decisions for school building. The interaction between the major parameters related to the aging of a building, maintenance activities, and cost were expressed in Causal Loop Diagram. Based on this, the formula for the relationship between causal maps was defined and converted to Stock and Flow Diagram. Through the completed SD model the 50-year plan of 214 educational building were tested by considered in account budget, maintainability, and budget allocation opinions. As a result, the integrated SD model demonstrated that it can support strategic decision making by identifying the status class and LCC behavior of school buildings by scenario. According to the scenario analysis, the rehabilitation action of preventive maintenance that primarily repairs the buildings in condition grade C showed the best performance improvement effect relative to the cost. Therefore, if the proposed SD model is expanded to consider the effects of other educational policies, the crucial performance improvement budget can be estimated in the long-term perspective.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.744-754
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• 2017

In this study, an analytic hierarchy process (AHP) was conducted with the aim of developing a post-disaster refugee housing performance index system (PPS) to improve the post-disaster refugee housing (PRH) performance criteria for the foundation of quality-based development. The PRH was defined as a mid-term temporary housing facility that is used for a certain period before the permanent housing is established. The safety, rapidity, reusability, habitability, and economy were derived from major performance factors through prior research. A hierarchical PPS was organized by linking the major performance factors with the whole life cycle process of PRH. The priority of each performance index of PPS was determined quantitatively using the analytic hierarchy process through an expert survey. Based on AHP analysis, the performance criterion of the total weight 1-10 ranking and the performance criterion of the first rank in each category were classified into the essential performance criterion (must be achieved) and the others were classified into the recommended performance criterion (optional achieved) and the performance index was constructed considering all stages of PRH development. With the completion of the PRH performance index, it is expected that victims will be able to secure stable residence and return to their daily lives quickly.