• Nuclear Engineering and Technology
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• 제56권3호
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• pp.1037-1051
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• 2024

This paper presents the construction results and design of the UNIST Reactor Innovation platform for small modular reactors as a versatile testbed for exploring innovative technologies. The platform uses simulant fluids to simulate the thermal-hydraulic behavior of a reference small modular reactor design, allowing for cost-effective design modifications. Scaling analysis results for single and two-phase natural circulation flows are outlined based on the three-level scaling methodology. The platform's capability to simulate natural circulation behavior was validated through performance calculations using the 1-D system thermal-hydraulic code-based calculation. The strategies for evaluating cutting-edge technologies, such as the integration of a solid oxide electrolysis cell for hydrogen production into a small modular reactor, are presented. To overcome experimental limitations, the hardware-in-the-loop technique is proposed as an alternative, enabling real-time simulation of physical phenomena that cannot be implemented within the experimental facility's hardware. Overall, the proposed versatile innovation platform is expected to provide valuable insights for advancing research in the field of small modular reactors and nuclear-based hydrogen production.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.174-178
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• 2015

This paper presents a new method for forecasting construction project cost and time at completion or at any intermediate time horizon of the project duration. The method is designed to overcome identified limitations of current applications of earned value method in forecasting project cost and time. The proposed method usesfuzzy set theory to model uncertainties associated with project performance and it integrates the earned value technique and the contractors' judgement. The fuzzy set theory is applied as an alternative approach to deterministic and probabilistic methods. Using fuzzy set theory allows contractors to: (1) perform risk analysis for different scenarios of project performance indices, and (2) perform different scenarios expressing vagueness and imprecision of forecasted project cost and time using a set of measures and indices. Unlike the current applications of Earned Value Method(EVM), The proposed method has a numberof interesting features: (1) integrating contractors' judgement in forecasting project performance; (2) enabling contractors to evaluate the risk associated with cost overrun in much simpler method comparing with that of simulation, and (3) accounting for uncertainties involved in the forecasting project cost.

• 한국해안해양공학회지
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• 제19권6호
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• pp.533-546
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• 2007

본 연구는 턴키 발주공사의 전면적인 재설계 과정에서 원가절감과 사용자 중심의 요구조건을 충족 시킬 수 있는 여러 방법들 중에서 설계 VE(Value Engineering: 가치공학) 프로세스를 적용한 연구이다. 본 연구에서는 설계 VE 프로세스를 사용하여 합리적이고 실용적인 기능분석 프로세스를 단계별로 정립하였다. 설계 VE가 가지고 있는 문제점으로 프로젝트 시행 시기별 적용 프로세스를 계획단계에서 분석할 수 없는 한계점이 있었으며, 또한 대형프로젝트 수행 과정에 초기분석 및 검증을 할 수 없었다. 본 연구에서는 컴퓨터 시뮬레이션 기법을 도입하여 설계 VE가 가지고 있는 문제점을 보완하고, 효율성과 안전성 등을 증명하였다. 기존에 적용해 온 VE기법은 항만시설물 건설에 적용시 시공분야에만 국한하여 적용됨으로써 기능 및 건설비 절감에는 기여하지 못한 것으로 나타났다. 그러나 본 연구에서 제안한 VE 대상선정 방법에 의하여 기능분석 프로세스를 합리적이고 실용적으로 개선함으로써 재설계 VE 수행절차를 효율적으로 개선 할 수 있었다. 본 연구에서 최적화시킨 VE 기법을 항만시설공사에 실제 적용시킨 결과 약 46억 원의 공사비를 절감하는 효과를 거두었다. 따라서 본 연구 결과를 유사프로젝트에 적용 할 경우 VE를 효과적으로 달성 할 수 있을 것으로 사료된다.

• 한국강구조학회 논문집
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• 제12권3호통권46호
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• pp.317-328
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• 2000

본 연구의 목적은 재료 및 기하학적 비선형을 고려한 고등해석을 이용한 브레이싱된 강뼈대구조물의 최적설계 알고리즘을 개발하는데 있다. 구조물의 해석과정에서 비선형효과를 모두 고려함으로써 기둥의 유효길이 연산이 필요없는 최적설계 알고리즘을 제시하였으며, 전체 구조시스템 및 개별부재의 정보를 이용하여 최적화 하는 2 파라미터형 다단계 최적화 기법을 개발하였다. 해석기법은 단면소성힌지(zero-length plastic hinge) 개념을 이용한 개선된 소성힌지해석법을 수행하였으며, AISC-LRFD '94 규준을 이용하여 최적화 문제를 형성하였다. 본 알고리즘을 브레이싱된 강뼈대구조물에 적용하여 본 연구의 타당성, 효율성, 경제성을 비교검토 하였다.

• 한국강구조학회 논문집
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• 제19권4호
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• pp.395-402
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• 2007

허용응력설계법과 강도설계법으로 설계된 강합성 플레이트 보강형과 콘크리트 보강형으로 구성된 장대교량인 복합사장교의 확률적 위험도 평가를 수행하였다. 최대 축력, 전단력 및 정 부모멘트 발생단면에 기초한 위험단면에 대해 AFOSM 알고리즘과 시뮬레이션기법을 사용하여 케이블, 주탑, 보강형 및 강-콘크리트 접합부의 요소신뢰성을 평가하였다. 체계신뢰성해석을 위해, 케이블, 주탑 및 콘트리트와 강합성 보강형으로 구성된 복합사장교의 시스템을 조합 파괴모드로 모델링하였으며, 이를 통해 전체 구조시스템의 파괴확률과 신뢰성지수를 산출하였다. 본 연구를 통해 복합사장교의 거동특성에 기초한 파괴모드를 제안하였고 위험도평가 방법으로서 부분 ETA기법의 효용성을 확인하였다.

• 한국조경학회지
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• 제22권1호
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• pp.135-148
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• 1994

When we put a construction on the space organization form of Seyeon-jong garden through a consequence of drawing analysis, we were able to certify that a certain space construction principle was applied as following. First, the arrangement and organization of space construction element embodied systematic order y clearing the character of space, and heightening the degree of cognizance with the means of functionability, scale, height, decorationability, an inclination of artificiality and nature, systemetic approchability. Second, the space construction element of Seyeon-jong garden pursued a harmony of human work and nature for creating a various atmosphere and visual quality. Third, Seyeon-jong garden constructed the space by establishing the measurement of human scale that introduced a conception of near, middle, distant view on the visual angle. Forth, Yun go san introduced the natural shape of 'The song of five friends' as a construction element, and represented the symbolism that he had seeked for throught he arrangement method, christening, composing technique of the space construction element for expressing ideal space which is described in 'The four season song of fishermen' spatially at Seyeon-jong garden. As the results of this study, that Yun go san created his own ideal space that he longed for at Seyeon-jong garden with applying fixed design system, and he realized his will that he strived to form a complete whole in perfect harmony.

• 한국주거학회논문집
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• 제24권4호
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• pp.53-60
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• 2013

Apartments amount to 58.3%, the highest proportion of domestic housing types. These apartments' lifespan (approximately 27 years) are one-third of the developed countries' housing lifespan due to the property developers and mass production. It is significantly short-cycle period considering the original physical lifespan of the apartment housing are 60 years. It has caused economic loss and environmental degradation. In recent years, research and development for the long life of the apartment housing has been actively performed, but it is limited on reconstruction and new construction. Reconstruction of existing a number of high-rise apartments is difficult owing to restrictions on the floor area ratio allowing for 40 years limit of decay resistance after the completion. Improving lifespan of the building has recently begun to receive attention as an alternative to remodeling. However, These sort of remodeling techniques tend to be focused on technology developed for the physical life extension. That means developing the techniques about dwelling-unit environment for residents satisfaction are required as well as improving physical construction. The purpose of this study is to propose and verify the Participatory Design Technique which can help the residents as the active participation in the design decision-making process.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.65-84
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• 2002

The Observational Method proposed by Terzaghi can be applied for the safe and economic construction projects where the exact prediction of the behavior of the structures is difficult as in the underground excavation. The method consists of measuring lateral displacement, ground settlement and axial force of supports in the earlier stage of the construction and back analysis technique to find the best fit design parameters such as earth pressure coefficient, subgrade reaction etc, which will minimize the gap between calculated displacement and measured displacement. With the results, more reliable prediction of the later stage can be obtained. In this study, back analysis programs using the Direct Method, based on the Hill Climbing Method were made and evaluated, and to overcome the limits of the method, Genetic Algorithm(GA) was applied and tested for the actual construction cases.

• 한국건설관리학회논문집
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• 제25권2호
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• pp.69-80
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• 2024

Currently rebar spacing inspection is carried out by human inspectors who heavily rely on their individual experience, lacking a guarantee of objectivity and accuracy in the inspection process. In addition, if incorrectly placed rebars are identified, the inspector need to correct them. Recently, laser scanning and AR technologies have been widely used because of their merits of measurement accuracy and visualization. This study proposes a technology for rebar spacing inspection and fixing by combining laser scanning and AR technology. First, scan data acquisition of rebar layers is performed and the raw scan data is processed. Second, AR-based visualization and fixing are performed by comparing the design model with the model generated from the scan data. To verify the developed technique, performance comparison test is conducted by comparing with existing drawing-based method in terms of inspection time, error detection rate, cognitive load, and situational awareness ability. It is found from the result of the experiment that the AR-based rebar inspection and fixing technology is faster than the drawing-based method, but there was no significant difference between the two groups in error identification rate, cognitive load, and situational awareness ability. Based on the experimental results, the proposed AR-based rebar spacing inspection and fixing technology is expected to be highly useful throughout the construction industry.

• 한국실내디자인학회논문집
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• 제15호
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• pp.79-85
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• 1998

Woods have been the familiar constructional materials because they were well suited to natural environments of Korea in terms of history regionalism and nationality. Since the modernization of Korea the wooden structure have mostly disappeared because of constructional costs regulations and convenience. But wooden constructions will reappear because of a prediction of wood demand and supply various choices for life circumstances and various investigations. There are many such cases. Among them Japan became an interesting object of investigation. New wooden constructional structures with new materials and modern skills may be observed in Japan. The purpose of this study is to trace architects' consciousness and to analyze constructions with the combination of wooden and other materials in Japan. Thus we explore a possibility to construct a new wooden structure which is suitable in modern Korea. The results were as follows: First the consciousness of Japanese architects' mixed wooden construction corresponds to the close relations between society and environment. Second the space of a structure with mixed wooden constructions in present Japan is chosen as the best way to consider functions and environments according to the form of need space scale and quality. Third the structure wooden constructional structure is a part of roof open space. in this case woods are represented and composed of japanese traditional wooden structure with new technique. Forth a mixed wooden construction has been used through a merit of each material by mixed of different materials as well as beauty of form.