• 한국건설관리학회논문집
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• 제6권5호
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• pp.69-77
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• 2005

Change is inevitable and is a reality of construction projects. Most construction contracts include change clauses and allowing contractors an equitable adjustment to the contract price and duration caused by change. However, the actions of a contractor can cause a loss of productivity and furthermore can result in disruption of the whole project because of a cumulative or ripple effect. Because of its complicated nature, it becomes a complex issue to determine the cumulative impact (ripple effect) caused by single or multiple change orders. Furthermore, owners and contractors do not always agree on the adjusted contract price for the cumulative Impact of the changes. A number of studies have attempted to quantify the impact of change orders on project costs and schedule. Many of these attempted to develop regression models to quantify the loss. However, regression analysis has shortcomings in dealing with many qualitative or noisy input data. This study develops ANN models to classify and quantify the labor productivity losses that are caused by the cumulative impact of change orders. The results skew that ANN models give significantly improved performance compared to traditional statistical models.

• 한국농공학회논문집
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• 제60권4호
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• pp.1-13
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• 2018

The grain complex of Saemangeum is created for promoting the foundation of agriculture combined the global competitiveness. However, the masterplan is being also revised with changing of local conditions and social needs. Thus, the dynamic masterplan is needed to consider the change of time for Saemangeum project. The present study was made to set up the dynamic masterplan of Saemangeum grain complex for handling the change such as project progress, local environment, and project conditions flexibly. In this study, the dynamic masterplan for the progressive development of water supply, farmland composition, and introduction facilities is presented to the 6-2 zone in three stages. We believed that the water supply would be possible through the pumping and desalination facilities with the development stages. The farmland composition proceeded for each complex with reclamation, soil preparation, and soft soil processing. And it is planned to carry out crop cultivation from the complex where the construction is completed first. The introduction facilities were analyzed focusing on the silos and forage loading facilities, and the optimal location of them was selected using road and accessibility. The concept of dynamic masterplan may provide the direction for the planning and progress of reclamation project.

• 건축역사연구
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• 제27권2호
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• pp.51-62
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• 2018

This study examines the site and erection of the Government Complex Seoul which was a project attempted to assemble dispersed government buildings in a certain place. The study focuses on the fact that the project is situated between the 1960s' making of capital Seoul and Seoul urban planning, and the way how the project achieved symbolism in capital Seoul. The project, one of the 1960s' Major Government Buildings, led both plan of capital Seoul and transforming city Seoul. The 1960s' Major Government Building Plan had identical drive with the 1950's Major Government Building Plan, however the 1960s' had additional layer: Seoul urban planning. After restoration of the Capital building, Sejongro the capital street was planned to the site arranging government offices. The Government Complex Seoul was set to be a modern building on a site with historical context according to the plan. Because of the site, the Government Complex Seoul was constructed in aware of other buildings that represented a competitive high-rise atmosphere in the late 1960s, including the Capital building nearby. PAE International's plan was completed through a series of design modification, and it boasted a vertical aspect, unlike the horizontal-looking plan that was already won after the design competition. The Government Complex Seoul tried to acquire the symbolism in the central space of the capital Seoul and high-rised city Seoul. "The new construction method" was a requirement to achieve the height.

• Architectural research
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• 제11권2호
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• pp.35-42
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• 2009

Recently, intensive urban redevelopment concentrated on new towns has reduced the number of settled population, and weakened various functions such as commercial, culture, education and welfare in old towns, and made the stagnation and declination of the entire or some parts of old towns. Urban regeneration project means renewing cities' functions in terms of physical, environmental, social, cultural, industrial and economic aspects or revitalizing the existing functions through improvement project in the entire or part of a city, which is now drawing keen attention from the public. However, urban regeneration project is huge in scale, needs long construction period and various complex facilities, and also characterized by complicated relations with many stakeholders. Due to such characteristics, there are many risks in the project. Therefore, systematic risk management is absolutely necessary to efficiently manage various risk factors inherent in urban regeneration project. The purpose of this research proposes a basic model to establish risk management plan and work process in order to help project participants to perform risk management more systematically and rationally in the development phase of urban regeneration project.

• 한국건설관리학회논문집
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• 제17권3호
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• pp.71-80
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• 2016

대규모 복합 프로젝트(complex project) 또는 메가 프로젝트(mega project)들에서 확률적으로 공정계획을 수립하는 대표적인 방법이 PERT (Project Evaluation and Review Technique)기법이다. PERT기법은 작업공기의 불확실성에만 중점을 두고 작업간 연결관계는 Finish-to-Start(FS)관계로 제한되기 때문에 작업간 중복관계가 존재할 경우 작업간 연결관계의 불확실성에 대한 확률적인 추정이 불가능하다. PERT기법의 이러한 한계를 극복하기 위해, 작업간 다양한 중복관계들의 불확실성을 고려하여 사업전체 공기를 추정하는 방법으로 PLET (Probabilistic Linkage Evaluation Technique)기법을 제안되었다. 그러나 PLET 기법에 의한 사업공기 추정은 작업간 연결관계의 불확실성만을 고려할 뿐, PERT기법에서의 작업공기에 대한 불확실성은 고려하지 않으므로, 완전한 사업공기 추정방법이라 할 수 없다. 본 논문은 작업공기의 불확실성을 고려하는 PERT기법과 작업간 연결관계의 불확실성을 고려하는 PLET기법을 결합시켜 사업공기를 추정하는 통합 모델을 제안하고 확률적 타당성을 검증한다. 그리고 통합 모델의 일정계산방법을 제시하고 이를 실제사례에 적용하여 검증함으로써, 고위험 건설사업의 공정계획을 수립할 때 보다 폭넓고 다양한 위험요인들을 통합적으로 고려하는 확률적 사업공기 추정 방법을 제안하는 것이다.

• 대한안전경영과학회지
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• 제25권2호
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• pp.113-120
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• 2023

Occupational safety and health management expenses in the construction industry are statutory and separately included in the cost statement to prevent occupational accidents and health problems. The expenses are determined by multiplying the standard amount by the rate decided according to construction types and scales. However, the current expense appropriation method does not properly reflect the recent changes in the construction industry such as industry size, industry diversification, and social atmosphere about safety reinforcement. This study surveyed 1579 questionnaires in total and analyzed expense execution rate and proportion of each expense category. The expense execution rate was relative higher in complex construction (e.g., heavy construction = 126%, civil engineering = 125%) and long-period project (equal to or over 48 months construction = 133%) compared to general construction (98~116%) and short-period project (less than 48 months construction = 115%). The proportion of spending expenses was higher in the category of safety manager labor costs (25~52%), safety facility costs (22~40%), and personal protective equipment costs (10~25%). The analysis results of the study can be utilized in revising the standard expense appropriation method by reflecting the current usages of the occupational safety and health management expenses in the construction industry.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2003년도 학술대회지
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• pp.202-213
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• 2003

타워팰리스 III 현장은 현존하는 국내 건축물로는 가장 높은 초고층 주상복합건물이다. 초고층 현장에는 일반현장과는 다른 시공기술 및 엔지니어링 기술의 적용이 요구되는 바, 타워팰리스 III 현장은 지금까지 축적된 기술을 바탕으로 보다 발전된 시공기술과 엔지니어링 기술, 그리고 공정관리기법을 통하여 마감공사 포함 충 당 13.4일이라는 공사 속도를 달성하였다. 이와 같은 공사를 성공적으로 수행하기 위하여 적용된 첨단 시공기술로 1) 골조공사 및 외벽공사의 3-Day Cycle을 달성하기 위한 여러 가지 공법, 2) 초고층 주거건물의 마감공사 공정관리를 위한 Tact 공정관리 시스템, 3) 현장관리 시스템으로 물류관리 및 정보공유 시스템 등이 적용되었다. 또한 엔지니어링 요소기술로 1) 고유동 무다짐 콘크리트와 국내 최초의 압축강도 $800kgf/cm^{2}$의 초고강도 콘크리트 등의 New Material, 2) 냉각수 순환형 파이프쿨링 시스템 등의 New Method, 3) Smart Fan Control 주방환기 시스템을 포함한 Mechanical System 4) False Car System을 포함한 Electrical System 등이 있다.

• 한국농공학회논문집
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• 제60권4호
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• pp.15-25
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• 2018

The accident risk at the construction workplace associated with agricultural engineering is comparatively higher than those of other fields due mainly to its complex work types and processes. Agricultural engineering deals with a variety of agricultural infrastructures from irrigation and drainage facilities to giant-scale coastal reclamation land infrastructures. The characteristics that most agricultural projects have conducted on a small-scale even worsen the situation drawing low attentions to risk management. Therefore, systematical risk assessment that focuses on details of agricultural construction work process is required in order to enhance safety management capacity and to prevent repetitive accidents ultimately. This study aims to categorize construction work types and processes of agricultural construction works, and to quantitatively assess the accident risk of them based on accident analysis. Regarding classification of construction works, actual 827 accident cases were thoroughly reviewed and coded by their construction site, facility and work type, project scale and so on. Most accidents (71.8 % of total cases) occurred in small-scale construction workplaces with less than 5 billion Korean won project budget. And those accidents related to agricultural infrastructure project (37.4%) and agricultural water development project (22.4%). In terms of work types, accidents frequently took place in form-work followed by pipe installation work, steel bar work and concrete work. The potential risks were compared with actual outbreak of accidents based on Analytic Hierarchy Process (AHP). The results show that the potential conditions of accident expected to be took place is somewhat different from the actual conditions where accidents actually happened. This implicates that risk management manuals or education needs to be adjusted by reflecting unexpected circumstances. Overall, this study is meaningful in that the results could be foundations as to strengthen risk management capacity for agricultural engineering projects.

• 국제초고층학회논문집
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• 제6권1호
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• pp.33-47
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• 2017

This mixed-use Raffles City (RCH) development is located near the Qiantang River in Hangzhou, the capital of Zhejiang province, located southwest of Shanghai, China. The project incorporates retail, offices, housing, and hotel facilities and marks the site of a cultural landscape within the Quianjiang New Town Area. The project is composed of two 250-meter-tall twisting towers with a form of vibrant waves, along with a commercial podium and three stories of basement car parking. It reaches a height of 60 stories, presenting views both to and from the Qiantang River and West Lake areas, with a total floor area of almost 400,000 square meters. A composite moment frame plus concrete core structural system was adopted for the tower structures. Concrete filled steel tubular (CFT) columns together with steel reinforced concrete (SRC) beams form the outer moment frame of the towers' structure. The internal slabs and floor beams are of reinforced concrete. This paper presents the engineering design and construction of this highly complex project. Through comprehensive discussion and careful elaboration, some conclusions are reached, which serve as a reference guide for the design and construction of similar free-form, hybrid, mix-use buildings.

• 대한토목학회논문집
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• 제35권3호
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• pp.715-723
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• 2015

단지 조성을 위한 토공사는 대상 부지의 지형고를 계획고와 맞추기 위한 대규모 토량이동으로 이루어지는 공사로 전체 공사비에 20~30%를 차지하는 중요한 공정이다. 한편 토공사는 주로 적재-운반-하차-복귀의 단순 작업사이클로 구성되어 있어 계획의 품질은 공기와 비용에 매우 큰 영향을 끼친다. 본 연구에서는 대규모 단지 조성 공사에서 토공 운반거리를 최소화할 수 있는 토량구획 모델을 제시하였다. 본 모델은 구획 알고리즘과 simulated Annealing 알고리즘에 기반하고 있으며, 이러한 알고리즘은 국부해에 빠질 수 있는 현행 토공구획 방법을 개선하기 위하여 도입되었다. 제시된 모델의 적용성을 평가하기 위하여 실제 단지공사 토량이동도를 대상으로 시뮬레이션을 실시한 결과 약 14%의 개선효과를 확인하였다.