• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.2179-2183
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• 2009

As urbanization is progressed, the network for distributing water in a basin become complex due to the spatial expansion and parameter uncertainties of water supply systems. When a long range water supply plan is determined, the total construction and operation cost has to be evaluated with the system components and parameter uncertainties as many as possible. In this paper, the robust optimization approach of Bertsimas and Sim is applied in a hypothetical system to find a solution which remains feasible under the possible parameter uncertainties having the correlation effect between the uncertain coefficients. The system components to supply, treatment, and transport water are included in the developed water supply system and construction and expansion of the system is allowed for a long-range period. In this approach, the tradeoff between system robustness and total cost of the system is evaluated in terms of the degree of conservatism which can be converted to the probability of constraint violation. As a result, the degree of conservatism increases, the total cost is increased due to the installation of large capacity of treatment and transportation systems. The applied robust optimization technique can be used to determine a long-range water supply plan with the consideration of system failure.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 추계 학술논문 발표대회
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• pp.15-16
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• 2016

Ways to efficiently manufacture gloss exposed mass concrete at an inexpensive price, in other words, ways to paste transparent transfer paper onto the surface of a combined mold has been designated as New Technology Article 191 by the Ministry of Land, Infrastructure and Transport. But if the difference in the coefficient of linear expansion between the mold's and transfer paper's material causes temperature to rise or fall, a wrinkly surface can appear. Therefore this study, by experimentally comparing the deformation characteristics between the mold material and transfer paper material upon changes in temperature, seeks to serve as a basic reference point for selecting the optimal transfer paper for different mold types. Study results revealed that for molds, polyester resin transfer paper is optimal, and for aluminum molds, acrylic resin transfer paper is.

• 한국환경복원기술학회지
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• 제9권4호
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• pp.36-51
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• 2006

Although the demand and necessity for the facilities of nature environmental conservation and its utilization have been increased recently, the local governments has been experiencing difficulties to launch the facilities since there are no confirmed principles or guidelines for the direction of the facility and distinctions from the ordinary parks. In this regard, the aim of this paper is to provide the overall framework for establishing the facility by equipping checklists from planning to operational stage. The stages are disengaged into 5 steps of siting feasibility, planning, preliminary environmental assessment and environmental impact assessment, design, construction, and operation. This paper also include the recommendations to vitalize the existing facilities, of which expansion of educational program development; utilization of various manpower; provision of appropriate settings; strengthened monitoring; and increased public relations. Furthermore, it is suggested to consider the strengthened local characteristics, reviewing management plan at the stage of applying a new facility establishment to the concerned authority, fostering experts, and expansion of the facilities through restoration of environmentally damaged areas for a new facility.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.443-445
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• 2001

As the new large buildings are continuously being built with the advanced technology and skills, an adequate size of electric room needs to be obtained so that engineers establish an efficient and reliable system in the electric room. Considering the current capacity, its expansion and its connecting system, the final size of it should be determined in order to bring an effective use of the building. Usually the extension of electricity capacity is on the increase after construction and it comes from the lack of scientific evaluation on the electric room. Later when the expansion of computer and important electric equipment that needs much capacity is impossible, it will cause a great deal of damage to the renting business of the building as well as becomes the unstable factors of the whole system. Therefore, it is important to have the exact method of calculating the effective size of electric room, the heart of the building, especially when the value of land price is very high. In addition, it should be calculated in an accurate way due to the diversification of the system and the compact size of the electricity equipment. However, the research on this area and the comparison and evaluation of the size after construction have not been made enough and the results of them have not been applied when calculating a new size of electric room. Accordingly, this study examines three methods prescribed in the standards of electricity installation technology through case analysis and suggests substantial data by system, capacity, and purpose.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.71-79
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• 2008

The concrete track is being used at the Phase II of the Kyeongbu High Speed Railway and New Constructed Honam High Speed Railway. When it makes a decision of bridge type, It has to consider about longitudinal forces of Continuous Welded Rail, Displacement at the end of bridges, Up-lift forces for fastener on the track. If it is installed turnout on the bridge, There is likelihood of the deck twist by applying the each difference longitudinal forces at the 4 each rails and the buckling by concentration of rail stress at the turnout. Moreover, If it is installed turnout on the continuous bridge and REJ(Rail Expansion Joint) on the main track or turnout track. It is hard to keep a safety for rail because of coming to twist or folding at the expansion of deck on the turnout track. Therefore when it is a design of bridge with turnout. It need to take bridge type to minimize an additional axial force and a displacement at the turnout. This paper makes a study of the composite steel arch bridge that is able to resolve criteria requirements of safety for track with turnout and suggest a helpful design method for bridge considering track with turnout by being based on design and construction method of Eonyang Bridge at the north part of Ulsan Station in Phase II of the Kyeongbu High Speed Railway.

• 설비공학논문집
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• 제20권12호
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• pp.775-780
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• 2008

A dynamic model to simulate LNG reliquefaction process has been developed. The model was applied to two candidate cycles for LNG reliquefaction process, which are Reverse Brayton and Claude cycles. The simulation was intended to simulate the pilot plant under construction for operation of the two cycles and evaluate their feasibility. According to the simulation results, both satisfy control requirements for safe operation of brazed aluminum plate-fin type heat exchangers. In view of energy consumption, the Reverse Brayton cycle is more efficient than the Claude cycle. The latter has an expansion valve in addition to the common facilities sharing with the Reverse Brayton cycle. The expansion valve is a main cause to the efficiency loss. It generates a significant amount of entropy associated with its throttling and increases circulation flow rates of the refrigerant and power consumption caused by its leaking resulting in lowered pressure ratio. It is concluded that the Reverse Brayton cycle is more efficient and simpler in control and construction than the Claude cycle.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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• pp.57-60
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• 2009

In ultra-high-strength concrete, autogenous shrinkage is larger than dry shrinkage due to the consume of a large amount of cement and cementitous material, and this is a factor deteriorating the quality of structures. Thus, we need a new technology for minimizing the shrinkage strain for ultra-high-strength concrete. So, this paper have prepared super-high-strength concrete with specified mixing design strength of over 150MPa and have evaluated a method of reducing autogenous shrinkage by utilizing expander and shrinkage-reducing agent. According to the results of this study, with regard to the change in length by autogenous shrinkage, an expansion effect was observed until the age of seven days. The expansion effect was higher when the contents of the expander material were higher. In addition, ultra-high-strength concrete showed a shrinkage rate that slowed down with time, and the effect of the addition of expander material on compressive strength was insignificant. That is shown that required more database to be accumulated through experimental research for the shrinkage strain of members.

• International Journal of Air-Conditioning and Refrigeration
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• 제17권4호
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• pp.135-140
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• 2009

A dynamic model to simulate LNG reliquefaction process has been developed. The model was applied to two candidate cycles for LNG reliquefaction process, which are Reverse Brayton and Claude cycles. The simulation was intended to simulate the pilot plant under construction for operation of the two cycles and evaluate their feasibility. According to the simulation results, both satisfy control requirements for safe operation of brazed aluminum plate-fin type heat exchangers. In view of energy consumption, the Reverse Brayton cycle is more efficient than the Claude cycle. The latter has an expansion valve in addition to the common facilities sharing with the Reverse Brayton cycle. The expansion valve is a main cause to the efficiency loss. It generates a significant amount of entropy associated with its throttling and increases circulation flow rates of the refrigerant and power consumption caused by its leaking resulting in lowered pressure ratio. It is concluded that the Reverse Brayton cycle is more efficient and simpler in control and construction than the Claude cycle.

• 한국안전학회지
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• 제35권1호
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• pp.34-44
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• 2020

The purpose of this study is to suggest ways to improve the transparency of occupational safety and health management cost (OSHMC) in order to create a safe working environment that can guarantee the health of construction workers. It was performed in the following procedures and methods. (1) collecting and analyzing resources related to the OSHMC in construction, (2) gathering stakeholder opinions for interviewing actual conditions, (3) deriving the improvement plans based on survey results and (4) suggesting direction for improvement of related laws based on the results of the research. As a result of this study, the following ways were found to be effective for enhancing transparency of the OSHMC in construction. (1) disclosure of usage details in sites, (2) Expansion of the standard for the OSHMC in construction, (3) Increase in fines for false use, (4) Establishment of the plan to improve the OSHMC ratio of small-scale construction sites, (5) Strengthen the role of supervisory and support organizations such as the Ministry of Employment and Labor and the Korea Occupational Safety & Health Agency. The result of this study is expected to be used as a basic data for future improvement of the occupational safety and health acts in Korea.

• 한국건설관리학회논문집
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• 제17권3호
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• pp.3-12
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• 2016

최근 건설업계의 해외진출이 불가피한 상황에서 국내 설계도면의 경쟁력은 뒤처져있다는 평가를 받고 있다. 따라서 객관적 도면평가를 통해 국내도면수준을 파악하고, 설계경쟁력 확보방안을 마련하고자 한다. 실시설계도면을 기반으로 설계속성을 도출하고, 기존 유사연구와 전문가 인터뷰를 거쳐 속성을 보완한 뒤, 이들을 평가항목으로 Likert척도와 FMEA기법을 이용하여 실무자를 대상으로 설문조사를 실시하였다. 그 결과 국내도면의 상대적 수준에 대한 시공사와 설계사의 의견이 다르고, 중요성을 인지하는 속성이 상이함을 확인하고 그 이유를 분석하였다.