• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.48-50
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• 2019

항만 및 해안구조물의 안정성이나 연안지형 변화 등에 가장 주요한 외력조건 중 하나인 파랑의 효율적인 관측을 위하여, 선박용 X-band 레이다를 이용항 파랑 모니터링 시스템을 활용할 수 있다. 과거 해외 시스템의 국내 적용시 문제점을 개선한 3S-system (한동대학교 개발)의 건설현장 실적용 사례를 통해 실시간 공간관측 가능한 파랑 시스템 운영을 소개하고, 이를 해상공사 중 작업선박에 대한 관제시스템으로 확장 사용하는 안에 대하여 제시하였다. 향후 추가적인 확장성에 대해서도 공유하고자 한다.

• Water for future
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• v.56 no.9
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• pp.47-51
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• 2023

2023년 1학기(2023년 3월 2일~2023년 6월 20일) 동안 한국농어촌공사 농어촌연구원 국제융합수리시험센터(안산)에서 현장실습을 한것을 바탕으로 후기를 작성하였다. 현재 농어촌연구원은 농어촌 지역개발, 수자원의 효율적 이용과 관리, 농업 신기술 교육, 스마트팜 기술 보급, 친환경 농업, 남북협력 사업 등 농어업인의 환경 개선과 올바른 정책 방향성을 제시하기 위하여 다양한 분야의 연구를 수행하는 공공기관이다. 이번 현장실습을 경험한 국제융합수리시험센터는 1959년에 국내 최초로 수리모형실험을 시작하였으며, 2018년 대형 실험시설이 추가 증축되어 규모나 시설(장비) 측면에서 국내는 물론 세계 최상위 수준의 인프라를 보유하고 있다. 또한 댐, 하천, 해양, 신재생에너지 등과 관련하여 다수의 실험 실적 보유하고 있어 수 공학 분야의 국가경쟁력 강화에 견인하고 있다. 이번 현장실습은 수리실험 이론 교육, 실험장비 교육, 실험실습, 안전교육으로 구성되어 있다. 교육프로그램(HIGH Center ACE⁺)에 따른 학교에서 배운 전공 이론을 수리실험 분야에 어떻게 적용할 수 있는지 직접 실습하면서 배울 수 있었다. 4개월간 현장실습 교육프로그램에 참여하면서 수리실험 등 수공학 분야의 다양한 경험을 할 수 있었고, 이는 향후 전공과 관련된 직장을 준비하는 데 많은 도움이 될 것으로 생각된다.

• Korean Journal of Construction Engineering and Management
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• v.12 no.1
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• pp.53-61
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• 2011

For construction projects, the importance of early cost estimates is highly recognized by the project team and sponsoring organization because early cost estimates are frequently a foundation of business decisions as well as a basis for identifying any changes as the project progresses from design to construction. However, it is difficult to accurately estimate construction cost in the early stage of a project due to various uncertainties in construction. To deal with these uncertainties, cost estimates should be made several times over the course of the project. In particular, early cost estimates are essential process for successful project management. For accurate construction cost estimates, it is necessary to compare cost estimates with actual costs based on historical project data. In this context, case-based reasoning (CBR), which is the process of solving new problems based on the solutions of similar past problems, can be considered as an effective method for cost estimating. To obtain this, it is also required to define the attribute similarities and the attribute weights. However, no existing method is capable of determining attribute weights of qualitative variables. Consequently, it has been a well-known barrier of accurate early cost estimates. Using Genetic Algorithms (GA), this research suggests the method of determining the attribute weight of qualitative variables. Based on building project case studies, the proposed methodology was validated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.589-601
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• 2020

The Construction Standard Unit Price (CSUP) sets the standard for calculating the estimated construction cost. The CSUP is used as basic data for preparing a standard price for public construction. Currently, the CSUP is calculated in consideration of the market and construction field conditions. However, a long-term management plan was established to prepare revised standards. As part of the plan, a field survey was conducted on changes in construction conditions and market prices. However, the plan continued for more than 5 years. Thus, the plan has a problem of difficulty continuously managing primary activities that have high importance and high price volatility. Therefore, to efficiently manage the CSUP, this study identifies the primary activities of the CSUP and presents a management plan. Through importance analysis and unit price volatility analysis, 242 primary activities in 35 activity groups were identified. Also, a management plan is presented based on the importance levels of activities. The primary activities and management plan could enable the timely revision of important activities. The results of this study provide a base for reflecting the appropriateness of construction cost criteria on time.

• Korean Journal of Construction Engineering and Management
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• v.14 no.2
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• pp.96-107
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• 2013

Tower crane hoisting plan is one of the key element for the success of entire High-Rise Building construction. Hoisting time is the basic factor to appropriate hoisting plan which need to the hoisting load estimate and tower crane selection. With this reason, accurate hoisting time is needed to the proper hoisting plan. The current hoisting time estimation for High-Rise Building focus on the hoisting cycle time estimation with historical data. However, this method underestimated the external influences like environmental factor. Thus, this paper aims to develop the hoisting time estimation model with discrete event simulation which include the wind influences with certain height. According to the simulation result, the hoisting time which applied wind influence is increasing with height growth. Because of the high speed wind, the upper area of building has more operation delay time than the mechanical operation time. Seoul, the research area, has the most fastest wind speed on April and the least on October. Due to these differences of wind speed, the hoisting time is estimated with significant differences between April and October. This hosting time estimation model would be used for estimating the influence of wind. Moreover, this could apply to make the realistic hoisting plan.

• Korean Journal of Construction Engineering and Management
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• v.23 no.3
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• pp.13-24
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• 2022

Construction projects are exposed to various types of risks, which tend to increase. The increasing risks call for contractors' more attentions to forecasting and dealing with these risks. One of the measures to deal with contractors' risks is to forecast or estimate risk cost and include it in the construction budget. Although various researches in relation to risk cost have been observed, little attention has been paid to general contractors' perceptions and current practices in estimating risk cost of construction budget. The objective of the study is to identify and discuss key characteristics and implications based on the survey and analysis of general contractors' perceptions and current practices in estimating risk cost of construction budget. The study shows that there is a gap between the perception and the practice of estimating risk cost, that is, high perception of the importance of risk cost and a relatively low level of practice. It suggests that historical cost data, guidelines and corporate-level standard procedures are required to improve the current practice in addition to sufficient time allocations for risk cost estimating. It discusses that there is a need for using sophisticated estimating techniques including bid data analytics despite a low level of the current adoption, and also proposes that research and development in the field of the sophisticated estimating techniques should be further implemented in order to increase their practicality.

• Korean Journal of Construction Engineering and Management
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• v.21 no.2
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• pp.59-69
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• 2020

The regulation of business area was abolished to improve the competitiveness of the construction industry and the ability of general and specialty contractors to enter the mutual market. As the next step, the government is preparing for a reorganization of business type. If the impact of the abolishing of business area on the construction industry is analyzed, the result can contribute to determining the step by step application scope of the reorganization of business type. This study derived the business types having a high probability of the mutual market entry of general and specialty contractors. Then, the size of mutual market entry is analyzed. First, the connection between the general and specialty construction, and the similarities between the registration standards of general and specialty construction are analyzed. Based on the result, a general contractor can enter 15 business types of specialty construction, and the market size is about 78.8 trillion KRW. This is about 82% of the total contract cost of specialty construction during the year 2017 (about 96 trillion KRW). Next, based on the relevance of business contents, the market size when general contractors enter the specialty construction market is analyzed. As a result, the market size is about 24.7 trillion KRW, and this is about 13% of total contract cost of general construction during the year 2017 (about 190 trillion KRW). Based on the result of this study, there is a higher probability of the mutual market entry of general contractors into specialty construction than vice versa. However, the result of this study is based on the current contents of business types, registration standards, and construction data of before abolishing the regulation of business area. This is a research limitation. If the business contents and registration standards are changed in the future, the result could differ from the current result.

• Journal of the Korea Institute of Building Construction
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• v.14 no.5
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• pp.415-422
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• 2014

There is growing difference between a planned value and an actual cost for increasing as an risk of construction cost. A construction cost index is an alternative to redeem a problem, but it is still very difficult to reduce an actual differential as a price fluctuation. Furthermore an existing theory of a construction cost index is overly complex, and is unsuitable for using in working-level. This study suggests an optimum correction rate in respect of a total construction cost. It is analyzing the actual cost of 53 public buildings that the Public Procurement Service ordered. The objects are main processes that include architectural works, mechanical works, electrical works, telecommunication works, and service facilities. It is compared a total construction cost based on absolute error rate using the median from frequentist principle. For this, it is selected the suitable regression model and set a correction rate.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.234-238
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• 2007

Since the plant industry is a total business, it has great impact on the related industries and generates high value. However, in order to have a competitive engineering skills and capabilities, the plant industry requires long-term investment and a continuous strategic planning at the consortium level or national level. Also, a system needs to be established to share the information of the plant industry's overseas orders awarded and success factors. Thus, this study has conducted a survey and case study of the plant construction in foreign countries. Statistical analysis was performed and a basic data structure was built as a means of improving the future technological capabilities of the plant industry.

• Korean Journal of Construction Engineering and Management
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• v.24 no.3
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• pp.3-11
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• 2023

This research examines the need for a quantitative and objective method of calculating baseline productivity in the construction industry, which is known for its high volatility in performance and productivity. The existing literature's baseline productivity calculation methods rely heavily on subjective criteria, limiting their effectiveness. Additionally, data collection methods such as the "Five-minute Rating" are costly and time-consuming, making it challenging to collect detailed data at construction sites. To address these issues, this study proposes an objective baseline calculation method using unimpacted productivity BP, a work check sheet to systematically record detailed data, and a data collection and utilization process that minimizes cost and time requirements. This paper also suggests using unimpacted productivity BP and comparative analysis to address the objectivity and reliability issues of existing baseline productivity calculation methods.