• Korean Journal of Construction Engineering and Management
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• v.15 no.4
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• pp.119-127
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• 2014

This study aims to determine whether or not the input output life cycle assessment (I-O LCA) model can be used to assess the carbon dioxide (CO2) emission of buildings in initial planning phase. To ensure this end, this study proposed I-O LCA model which is the simplified LCA model and Hybrid LCA model which is the detailed LCA model, and then assessed and compared the CO2 emission of six case projects (three apartment complexes and three educational facilities) using the two LCA model. The results of the case study showed that the CO2 emissions assessed by the I-O LCA is significantly similar to the CO2 emission assessed by the Hybrid LCA model. The similarity of results from both LCA models was 78.2-86.3% in apartment complexes and 59.9-84.8% in educational facilities. However, the CO2 emissions from I-O LCA model were smaller than the CO2 emissions from Hybrid LCA model in case study. Nevertheless, the case study showed that the I-O LCA model was capable of assessing the CO2 emission of buildings quite appropriately although the I-O LCA model is the simplified LCA model which considers only the construction cost. The I-O LCA model is expected to be a useful tool for assessing the CO2 emission of buildings in initial planning phase.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.791-800
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• 2013

Needs for developing a better way of cost estimating process for public construction projects have been widely recognized. Those needs are mainly from the early phases of the project through the construction life cycle due to the its importance to the control process. In contrast to the traditional estimating method based on unit-price references, this research utilized this following process. The first step is analyzing the real cost data from actual cost activities (2000~2010) about the statement of P.S.C(Prestressed Concrete) Box Girder Bridge. The collected data was broken into four categories based on technical construction methods such as I.L.M(Incremental Launching Method), M.S.S(Movable Scaffolding System), F.S.M(Full Staging Method), and F.C.M(Free Cantilever Method). The second, actual design documents including the actual cost estimating documents, drawings and specifications were carefully reviewed to cluster the cost itemized statement from four categories. It was also attempted to seek the proper breakdown of standard works that are responsible for more than 95 percentage in each categories in terms of its cost. The third, this research comes up the index for standard unit materials and unit price of standard work and develops the approximate estimating model applying for the specification(length and breadth of bridges) per square area that the user takes as well as suggests the practical application plan within the original time alloted.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.420-420
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• 2018

하천법에서 정의하고 있는 하천시설은 시설은 제방과 수문을 포함하여 20여종에 달한다. 이 중 하천유지 보수 매뉴얼(국토교통부, 2016)에서 정한 유지관리 대상은 총 14종이며, 국가 및 지방하천 정비와 유지관리에 4대강살리기사업 완료 시점인 2012년 이후 연간 약 1.3조원의 예산을 투입하고 있다. 연간 막대한 예산이 투입되어 관리되고 있는 하천관리의 효율성을 제고하기 위해 하천시설에 대한 생애주기관리기법적용 연구가 진행 중이며 이를 위해서는 하천시설의 성능에 대한 정확한 평가가 선행되어야 한다. 본 연구에서는 배수통문에 대한 성능평가모델을 산정하는 방법을 제시하였다. 우선적으로 배수통문의 설치년도와 시설물안전등급을 조사하고 등급별 평균사용연수를 산정하고 시설물 성능예측 기본식의 계수를 산정하여 성능평가모델 산정식을 도출하였다. 배수통문 성능평가모델 산정식과 등급별 평균 사용연수를 비교하여 산정식의 적용성을 검증하였다. 본 연구를 통해 하천시설의 사용연수에 따른 성능을 개략적으로 예측하여 유지관리예산 투입의 우선 순위를 결정하는데 기초자료로 활용이 가능하다고 판단된다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.197-201
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• 2008

Conceptual cost estimates for domestic highway projects have generally been conducted using governmental unit-price references. Inaccuracies in governmental unit-price data has repeatedly addressed in the Korean construction industry which often lead to poor decision making and cost management practices. Thus, needs for developing a better way of conceptual cost estimating has been widely recognized. This research is considered as the first step in developing such model using real-world cost data based on actual construction activities. The data analyzed in this paper includes 41 P.S.C (Prestressed Concrete) Box bridges which broke into 4 categories based on construction methods such as I.L.M(Incremental Launching Method), M.S.S(Movable Scaffolding System), F.S.M(Full Staging Method), and F.C.M(Free Cantilever Method). Actual design documents; including actual cost estimating documents, drawings and specifications were carefully reviewed to effectively break down cost structures for PSC girder bridges. Among more than 40 cost categories for each P.S.C girder bridge type, 7 of them were identified which accounted for more than 95% of total construction cost (ILM: 99.47%, MSS: 99.22%, FSM: 98.18%, and FCM: 98.12%). In order to validate the clustering of cost categories, the variation of each cost category has been investigated which resulted in between -1.16 % and 0.59%.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.40 no.3
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• pp.28-40
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• 2011

본 논문에서는 열섬완화대책에 관한 수치목표를 설정했을 때, 각 지역에 필요 대기 열부하 삭감량과 구체기술의 필요투입량 파악을 목적으로, 대기 열부하 삭감 포텐셜과 목표설정의 관계에 대해 검토하였다. 먼저, mesoscale 기상모델에 의해 과거회귀로부터 구체적인 수치목표를 구한 결과, 열대야 DH의 필요저감량은 대판평야(大阪平野)부의 공간평균으로 $10.7^{\circ}C{\cdot}h$, 인구 중첩평균으로 $12.5^{\circ}C{\cdot}h$가 산출되었다. 또한, 필요열부하 삭감량은 대판평야부(大阪平野部) 전체에서 일률삭감시에는 공간평균으로 11.5 $W/m^2$, 인구 중첩평균으로 12.0 $W/m^2$인 한편, 열부하 삭감 포텐셜이 큰 도심부를 중심으로 삭감을 행한 지역배분조건에서는 개략적으로 같은 양의 열부하 삭감으로 목표를 달성함을 나타내었다. 대판부(大阪府)내의 어떤 시구를 대상으로, 논문에서 뽑은 각종 열섬완화대책을 도입률 100%로 실시한 경우, 목표를 달성한 시구가 존재함을 나타내었다.

• Journal of the Korean Professional Engineers Association
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• v.20 no.3
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• pp.5-14
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• 1987

연속체의 해석에 있어서, 특별한 경우를 제외하고는, 구조물의 개략적인 거동을 파악해야 될 경우가 종종 있다. 이러한 요구에 부응하기 위해서 강체요소법(Rigid Element Method)이라 불리우는 새로운 해석법이 개발되었다. 강체요소법은 원래 평정연구실에서 벽식프리캐스트 철근콘크리트 구조물의 탄소성해석을 하기 위해서 개발된 해석법에 착안하여, 내수벽과 같은 연속체에 적용함으로서 시작된 수치해석법이다. 그 후 저자들은 도통쉘, 구형쉘 혹은 이들이 조합된 쉘구조물에 적용할 수 있도록 개발 확장하였다. 강체요소법의 기본개념은 연속체의 분해된 각 요소를 강체(rigid body)라고 가정하고, 각 요소들은 요소의 강성으로 치환된 가상스프링으로 서로 연결되어 있다고 가정하여, 이 가상스프링의 거동을 평가함으로서 전체구조물의 거동을 파악하는 해석법이다. 이때 요소의 주변에 취해진 스프링은 해석을 단순화하기 위해서 축력, 면내전단력 및 면외전단력만을 전달한다고 가정하고, 요소의 강체변위(자유도)는 요소내의 임의의 한 점에서 취하며, 이 점에서의 강체변위(rigid displacements)는 요소의 주변에 취해진 스프링을 통하여 다른 요소로 전달된다. 상기와 같은 강체요소법의 개념을 연속체의 탄성 및 탄소성해석에 적용하면, 해석적 개념이 단순할 뿐만 아니라 구조물 전체의 자유도수를 대폭 줄여 컴퓨터 계산시간을 절약할 수 있는 잇점이 있고, 거시적인 모델(macroscopic modeling)과 미시적인 모델 (microscopic modeling)의 중간적인 성격을 가지기 때문에 구조물의 파괴상황에 대해서도 그 개략을 파악할 수 있다. 본 논문에서는 강체요소법을 보다 일반화된 해석법으로 개발, 확장하기 위해서 종전에 단층스프링시스템(single-layer spring system)으로 해석이 어려웠던 문제점들을 보완한 복층프링시스템(double-layer spring system)을 사용함으로서 휨, 비틀림의 효과를 파악할 수 있는 이론적 개념을 적용한 새로운 구요소, 원통요소 및 평면요소를 개발하고, 이러한 강체요소들의 적합매트릭스의 유도 및 해석저긴 방법을 정식화하였다. 또 휨, 비틀림 및 전단력의 효과를 고려한 사각형원통요소 및 능형원 통요소를 이용하여 원통쉘의 탄성 및 탄소성해석할 수 있는 프로그램을 개발하고, 이 프로그램으로 캔틸레버로된 연속형철근콘크리트 원통쉘의 탄성 및 탄소성해석에 적용하여 구조물의 거동에 관한 수치해석의 결과, 즉 내력의 분포, 균열의 진전, 파괴의 상황 및 변형의 상태 등을 파악해 보았다.

• Korean Journal of Construction Engineering and Management
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• v.20 no.4
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• pp.22-33
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• 2019

The government has steadily revised and developed laws and systems for activating remodeling of apartments in response to the problems of aged apartments. However, despite such efforts, remodeling has yet to be activated. For many reasons, this study noted that there were no tools for reasonable profitability judgements and decision making in the preliminary stages of the remodeling project. Thus, the feasibility evaluation model was developed. Generally, the profitability judgements are made after the conceptual design. However, decisions to drive remodeling projects are made at the preliminary stage. So a feasibility evaluation model is required at the preliminary stage. Accordingly, In this study, a feasibility evaluation model was developed for determining preliminary stage profitability. Construction costs, business expenses, financial expenses, and generally sales revenue were calculated using the initial available information and remodeling variables derived through the existing cases. Through this process, we developed an algorithm that can give an overview of the return on investment. In addition, the preliminary stage feasibility evaluation model developed was applied to three cases to verify the applicability of the model. Although applied in three cases, the difference between the model's forecast and actual case values is less than 5%, which is considered highly applicable. If cases are expanded in the future, it will be a useful tool that can be used in actual work. The feasibility evaluation model developed in this study will support decision making by union members, and if the model is applied in different regions, it will be expected to help local governments to understand the size of possible remodeling projects.

• The Journal of Engineering Geology
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• v.19 no.1
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• pp.9-14
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• 2009

In this work applicability of a sharp-interface model to well-scale problems is examined. In coastal areas one of the main concerns in groundwater development is saltwater intrusion. To determine the saltwater intrusion at a well one needs to evaluate the saltwater content from a pumping well. We conducted laboratory sand-tank experiments to determine if a sharp-interface model can simulate the saltwater content of a pumping well. Lateral saltwater intrusion experiments and freshwater lens experiments are conducted. A partially penetrating well and a fully penetrating well are used. Comparison between numerical results and observation results indicates that the sharp-interface model can determine saltwater contents reasonably well. We conclude that a sharp-interface model can be applied to well-scale groundwater flow problems in coastal areas.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.3 s.37
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• pp.55-62
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• 2006

The purpose of the current research is to evaluate the possibility of landslides by using geo-spatial information system. Geological information has been summarized and stability analysis for infinite slopes has been conducted based on the force equilibrium. In addition, the analysis of landslides was performed based on probabilistic approach by using probabilistic variables which can include uncertainty of input parameters. For the purpose of testifing the applicability of the analysis method actual geological data from a construction site was obtained, thereby performing both a preliminary analysis for a large area and detailed analysis for a better result. As a result of the current analysis several issues such as the possibility of development of landslides, detailed analysis of where landslides are most likely to be developed were analysed by using two concepts of safety and index of failure probability.

• Journal of the Korean School Mathematics Society
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• v.14 no.2
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• pp.123-142
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• 2011

Recently, a number of researches acknowledge the importance of 'reflection' and 'reflective teacher education,' and they highlight the implication of 'reflection' on the teacher's profession or the teacher education. The reflective thought is interpreted as a subject that should be taught or a sort of strategy that a teacher should learn, while the aspect is excluded that reflection is the interaction between the innate knowledge and the practice. As a result, the reflective teacher education programs that increase the level of reflection are developed and practiced, and the reflection is accepted as a tool for increasing teacher professionalism. Reflective teaching is en essential and basic element for the development of teacher knowledge. In particular, such teacher knowledge might be being gradually expanded by a teacher's self-assessment on reflection on his own instruction. For this reason, this study develops an assessment framework on instruction which is comprized of teacher knowledge and instructional process. To accomplish this, in this study, teacher knowledge is considered as a whole practice knowledge combined by subject matter knowledge, understanding of learners, teaching and learning methods and assessment, and instructional environment. Also, success on instruction in mathematics class might depend on the acquisition of teacher knowledge, instructional planning, instructional execution, and furthermore reflection on instruction. Especially, this study emphasizes that 'reflection on instruction', the most important step of instruction be reflected and examined by the teacher himself.