• Architectural research
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• 제16권3호
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• pp.93-100
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• 2014

Existing BIM(Building Information Modeling) based energy evaluation tools cannot be utilized enough for the potential performance of BIM because most of them have not provided the integrated model for energy evaluation, assessment of the material, cost of the construction, and so on. This research aims to propose and develop a new application, EcoBIM, to support an integrated evaluation of the energy and cost efficiencies of the design alternatives within the design process. The proposed application functions as a BIM-based evaluation system that calculates energy-savings performance as well as the construction cost of the alternatives at the design stage. This study mainly focuses on the possibilities of developing the proposed technology. We also suggest an advanced design process using the proposed system, corresponding to changes of national regulations in Korea. This study deduce that EcoBIM can allow architects to make suitable decisions regarding energy- and cost-efficient designs. The proposed design process will allow architects not only to check the eco-friendly performance of design alternatives but also predict the operation cost in a certain period in the future. EcoBIM can prevent large-scale design changes required to obtain environmental certification and enable the owner to make an informed decision about the initial investment of construction according to the result of the analysis of the energy requirement at the design stage.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.67-73
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• 2022

Construction bid documents contain various errors or discrepancies giving rise to uncertainties. The errors/discrepancies/ambiguities in the bid document, if not identified and clarified before the bid, may cause dispute and conflict between the contracting parties. Given the fact that bid document is a major resource in estimating construction costs, inaccurate information in bid document can result in over/under estimating. Thus, any questions from bidders related to the errors in the bid document should be clarified by employers before bid submission. This study aims to examine the pre-bid queries, i.e., pre-bid request for information (RFI), from state DoTs of the United States to investigate error types most frequently encountered in bid documents. For the study, around 200 pre-bids RFI were collected from state DoTs and were classified into several error types (e.g., coordination error, errors in drawings). The analysis of the data showed that errors in bill of quantities is the most frequent error in the bid documents followed by errors in drawing. The study findings addressed uncertainty types in construction bid documents that should be checked during a bid process, and, in a broader sense, it will contribute to advancing the construction management body of knowledge by clarifying and classifying bid risk factors at an early stage of construction projects.

• 한국환경복원기술학회지
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• 제14권2호
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• pp.83-96
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• 2011

The open space of apartment complex has changed diversely according to construction periods which were divided into the introduction stage (the 1980s), the development stage (the 1990s), and the maturity stage (after 1999). This study set out to analyze the periodic changes of visual characteristics and preference with the open space of apartment complexes in Cheongju City. For analysis of visual characteristics and preference, nineteen adjectives that were determined to sufficiently express the feeling of the open space of apartment complex. The results are as follows. As for adjective image assessment by using descriptive statistics, favorable images were shown in complexes of maturity stage phase that were constructed after the liberalization of apartment sale in 1999. These results may be caused both by quantitative increase and diversification of materials in planting and landscaping furniture and by nature-friendly designing. The results of factor analysis by Varimax rotation method showed that common variance was 73.9%, which indicates higher explanation. The nineteen adjectives could be divided into three factors, 'pleasantness factor,' 'negative factor,' and 'irregular factor.' Visual preference was analysed by using Least significant Difference (LSD) by analysis of variance : complexes of maturity stage phase that were constructed according to the liberalization of apartment sale in 1999 were highest in assessment. The correlation between view preference and adjective images was analyzed by multiple regression analysis, and 'feeling like walking,' 'well-arranged,' 'beautiful,' 'friendly,' and 'clean' (in order) were adjective images that most affected the preference. As for the analysis of the correlation between visual preference and physical components of view, the preference increased as the rate of pavement and greens was higher, while it decreased as size of building was larger. Therefore, backgrounds of walking and greens had strong effects on the preference.

• 한국수자원학회논문집
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• 제45권12호
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• pp.1227-1241
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• 2012

본 연구에서는 목자판과 수면이 포함되어 있는 시차를 가진 두 영상에 대해 직사각형 검사영역을 설정하고 그 상관계수를 분석하여 수면을 판단하는 새로운 수면인식 기법을 제안하였다. 상관계수의 수직적인 값들로부터 임계치, 첨두값, 기울기, 분산비 등 4가지 방법을 이용하여 수면의 위치를 판정하였다. 흔들림 등으로 인해 두 영상의 위치가 불일치하여 생기는 문제를 제거하기 위해 추가로 영상의 흔들림을 보정하는 알고리즘과 통계적 필터링 기법을 적용하였다. 저수시에 촬영한 28개 지점의 영상에 개발한 수면 인식 방법을 적용하였다. 이 방법으로 계산한 수면은 목측 수면과의 평균상대오차가 3.4~5.7 cm 정도로 나타났다. 수면의 요동이 있을 경우, 이 방법은 기존 방법을 보완하여 영상수위계의 수위 측정성능을 높이는데 활용될 수 있을 것이다.

• 한국건축시공학회지
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• 제23권4호
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• pp.417-428
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• 2023

사고 원인에 대한 철저한 분석은 사고 재발 방지를 위한 필수적인 과정이다. 해체공사 사고의 원인을 살펴보면 작업자의 불안전한 행동, 불안전한 상태, 심리적·신체적 상태, 현장관리 원인 등 매우 다양하다. 현재 해체공사 사고통계는 지속적으로 조사·보고되고 있으나 사고 유형에 따른 보다 근본적인 원인 분류 정보가 필요하다. 본 연구에서는 하인리히의 도미노 이론을 바탕으로 해체공사 사고의 유형에 따라 사고원인(불안전한 행동, 불안전한 조건)과 휴먼에러(인적요인)를 분류하였다. 본 연구에서는 해체공사시 사고유형에 따라 사고원인을 체계적으로 분류하기 위해 QFD-FMEA(Quality Function Deployment - Failure Mode Effect Analysis) 3단계 모델을 사용하였다. 사고원인 분류 결과는 사고예방을 위한 안전지식 및 체크리스트로 활용할 수 있다.

• 한국유체기계학회 논문집
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• 제20권2호
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• pp.17-25
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• 2017

Prediction of performance and operating characteristics of a state-of-the-art ultra-supercritical (USC) steam turbine is an important issue in many ways. Theoretical and empirical correlation equations, developed a few decades ago, have been widely used in commercial programs for a prediction of performance. To improve of these correlation equations and apply them to the high pressure turbine of a USC steam turbine, computational fluid dynamic analysis was carried out and correlation equations to calculate efficiency variation of each stage were made. Both fluid dynamic characteristic and thermodynamic performance was analyzed for the development of the correlation equations. In particular, the impact of flow addition through an overload valve (OLV) between stages was examined throughly. The trend of pressure drop due to the flow mixing by the OLV flow addition was analyzed and an efficiency correlation equation considering the OLV flow was also made.

• 한국건설관리학회논문집
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• 제10권5호
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• pp.57-66
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• 2009

본 연구는 BTL사업 실시협약을 위한 협상단계에서의 쟁점이 되는 항목의 분석 및 그 발생 원인을 찾아보고 해결방안을 제시하고자 하였다. 이에 기 수행되었거나 또는 수행중인 협상에서 논의되고 쟁점화 되는 항목에 관하여 주무관청과 사업참여자를 대상으로 협상참여 주체들이 인식하고 있는 쟁점화정도를 분석하였다. 또한 협상단계 각 분야별 쟁점항목들의 계층 분석방법을 통한 쌍대비교를 통해 가중치를 산정하고 그 쟁점화정도를 정량적으로 도출하였다. 최종적으로 1차 계층의 6개 협상분야 중 4개 분야에 대한 발생원인 각 2개, 2개 분야에 대한 발생원인 각 1개를 도출한 후 그에 대한 해결방안을 제시하였다.

• Structural Engineering and Mechanics
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• 제8권2호
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• pp.165-180
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• 1999

The cost effectiveness of using steel roof systems for residential buildings is becoming increasingly apparent with the decrease in manufacturing cost of steel components, reliability and efficiency in construction practices, and the economic and environmental concerns. While steel has been one of the primary materials for structural systems, it is only recently that its use for residential buildings is being explored. A comprehensive system for the design of residential steel roof truss systems is presented. In the first stage of the research the design curves obtained from the AISI-LRFD code for the manufactured cross-sections were verified experimentally. Components of the truss systems were tested in order to determine their member properties when subjected to axial force and bending moments. In addition, the experiments were simulated using finite element analysis to provide an additional source of verification. The second stage of the research involved the development of an integrated design approach that would automatically design a lowest cost roof truss given minimal input. A modified genetic algorithm was used to handle sizing, shape and topology variables in the design problem. The developed methodology was implemented in a software system for the purpose of designing the lowest cost truss that would meet the AISI code provisions and construction requirements given the input parameters. The third stage of the research involved full-scale testing of a typical residential steel roof designed using the developed software system. The full scale testing established the factor of safety while validating the analysis and design procedures. Evaluation of the test results indicates that designs using the present approach provide a structure with enough reserve strength to perform as predicted and are very economical.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 추계 학술발표회
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• pp.66-75
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• 2006

As construction for road tunnel is increasing, various geotechnical conditions can be faced during the construction stage. Especially, if the tunnel is located in limestone area, many kinds of site investigations such as in-situ boring, electrical resistance survey, TSP(Tunnel Seismic Prediction) and etc., are conducted before and during the construction. By conducting these preliminary tests, location, size, and filling materials in limestone cavities can be approximately estimated. Once some cavities which can be harmful for tunnel safety are predicted, methods for ground reinforcement and tunnel excavation, corresponding those ground conditions, have to be established and verified by measurement data and numerical analysis. If necessary, invert lining should be also considered. In this paper, by studying some cases of tunnels constructed in limestone area, predicted problems during construction and rational countermeasures for those are presented.

• 한국건설관리학회논문집
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• 제5권6호
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• pp.138-145
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• 2004

공사에 소요되는 기간은 시설물의 품질과 비용에 직접적인 영향을 미치지만, 고등학교 시설공사의 경우 경험과 직관에 의거하여 공기를 산정하고 있어 공사수행과정에서 계약당사자 간에 분쟁이 많이 발생하고 있다. 본 논문은 고등학교 시설공사에 소요되는 기간의 산정에 영향을 미치는 다양한 요인을 분석하여 공기 산정기준을 제안하는 것으로, 인천지 역에서 최근에 개교한 고등학교의 실적자료를 수집하여 다중선형 회귀분석 하였다. 회귀분석 결과로 얻은 순 공사기간에 인천지 역의 기후특성을 고려하여 산정한 작업불가능기간을 더하여 총 공사기간을 산출 하였다. 본 논문에서 제안한 공기 산정식은 공사발주 및 계약 시 계약공기를 정확하게 산정 하는데 도움을 줄 수 있을 것이다