• Nuclear Engineering and Technology
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• 제48권1호
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• pp.33-42
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• 2016

Spacer grids play an important role in maintaining the proper form of the fuel assembly structure and ensuring the safety of reactor core design. This study applies the Monte Carlo method to the analysis of the neutronics effects of spacer grids in a typical pressurized water reactor (PWR). The core problem used to analyze the neutronics effects of spacer grids is a modified version of Korea Advanced Institute of Science and Technology benchmark problem 1B, based on an Advanced Power Reactor 1400 (APR1400) core model. The spacer grids are modeled and added to this test problem in various ways. Then, by running MCNP5 for all cases of spacer grid modeling, some important numerical results, such as the effective multiplication factor, the spatial distributions of neutron flux, and its energy spectrum are obtained. The numerical results of each case of spacer grid modeling are analyzed and compared to assess which type has more advantages in accuracy of numerical results and effectiveness in terms of geometry building. The conclusion is that the most realistic modeling for Monte Carlo calculation is the "volume-preserving" streamlined heterogeneous spacer grids, but the "banded" dissolution spacer grids modeling is a more practical yet accurate model for routine (deterministic) analysis.

• 한국CDE학회논문집
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• 제20권2호
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• pp.124-132
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• 2015

When Building Information Modeling (BIM) was introduced at the early stage, it was only utilized as a three-dimensional visualization tool. Nowadays, however, BIM is being studied for increasing design productivity and managing enormous information on building life cycle. One of the representative research is developing 'common prototype BIM libraries'. BIM data made of common prototype libraries should be utilized in various ways, quantity takeoff, code checking, energy analysis and so on. However, common prototype BIM libraries are not enough to estimate accurate cost. For example, composite wall libraries should be divided into several single objects, wall structure and finishes, for the quantity takeoff and construction cost calculation. In this paper, we are suggesting an automated division algorithm of composite wall and developing a system prototype for it. This study is expected to reduce extra modeling work and contribute to fast and accurate cost calculation in the construction.

• 대한토목학회논문집
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• 제42권4호
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• pp.571-579
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• 2022

본 연구는 부산·울산·경남 지역의 관광호텔을 대상으로 에너지사용량과 이들의 개별적인 호텔특성 및 입지특성 간의 관계를 실증분석하였다. 복합적인 관계식 도출을 위해 다중회귀모형에서부터 다수준회귀분석(multi-level regression analysis)으로 모형을 확장하였고, 이를 통해 건축물의 개별적인 특성만을 고려한 대부분의 선행연구에서 나아가 호텔이 위치한 지역의 입지적 특성과 호텔-지역 간 위계적 구조를 고려하여 좀 더 개선된 모형을 도출하였다. 분석결과에 따르면, 호텔의 규모, 연한, 서비스 등급과 같은 개별적인 특성은 에너지사용량을 설명하는 주요 변수이고, 그들의 영향은 지역적으로 유의한 차이를 보이는 것으로 나타났다. 또한, 중심상업지에 인접하거나 다수의 관광호텔이 밀집한 지역에 위치할수록 에너지사용량은 달라지는 것으로 나타났으며, 이러한 입지특성 또한 개별호텔의 에너지사용량을 설명함에 있어 주요한 요인임을 확인하였다. 이와 같은 결과는 건축물단위의 에너지정책과 소비수준이 높고 에너지 집약시설이 밀집한 지역에 대한 지역단위의 에너지정책이 함께 고려될 필요성을 시사하며, 관광산업의 지속가능성을 높이기 위한 지역적 책임을 제언한다.

• 조명전기설비학회논문지
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• 제29권1호
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• pp.70-79
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• 2015

In this paper, enhanced stand-alone operation and development of Matlab/Simulink model of emergency diesel based hybrid energy system is presented. Simulations based on the remote community or islands were performed for PV-diesel-battery hybrid system. Modeling of PV-diesel-battery integrated system is done to perform under the solar radiation and load conditions on Matlab/Simulink platform. The models of diesel generator unit, battery energy storage system, PV and frequency-power control are developed and simulation studies have been carried out under various conditions using Matlab/Simulink and SimPowerSystem. It is demonstrated that the proposed system can provide reliable and good quality power to the customers in diesel synchronous generator-based hybrid energy systems.

• 한국BIM학회 논문집
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• 제5권4호
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• pp.30-36
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• 2015

The Leadership in Energy and Environmental Design (LEED) has provided abundant resources and guidelines for a new project to become a sustainable anchor in the neighborhood. Paired with a range of checklist, LEED has strong influence on the standards for a sustainable building, and it also has played an iconic role in energy-efficient architecture. However, it is still unclear as to whether or not an LEED certified building enhances environmental benefits to its surroundings. If an LEED certification promises a baseline for an eco-friendly building, then a group of these structures should ensure significant environmental benefits to the society. This is the main question of this study, and the authors answer this hypothesis by examining the relationship of LEED certificates and their influence on outdoor temperature, especially in terms of urban heat island effect. The goal of this paper is to analyze the influence of the LEED certification on urban temperature as an indicator of sustainable architecture's regional interactions. If an LEED certificate is regarded as a strong contributor to a sustainable built environment, then a group of these certificates should result in greater benefits to society. To this extent, the authors question if there is any possible relationship between a large concentration of LEED certified sites and the temperature of their surroundings. To properly assess the research direction, Global Moran's I analysis, Local Moran's I analysis, and Hot Spot analysis are implemented to find the clustered areas of LEED certified buildings. For examining relationships between clustered area and its temperature, correlation efficients are calculated.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1993년도 가을 학술발표회논문집
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• pp.199-204
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• 1993

Noise and vibration induced by subway operation are one of the major factor that annoying residents living near the. railway. In general, lateral vibration was the major concern when we are considering vibration of the building. Since the energy due to earthquake is enormous it affects wide area. However, the vertical vibration became a major concern in considering the vibration induced by subway because relatively smaller energy affects only nearby areas than that of earthquake. Analysis model of the structure for the vertical vibration should consider the effect of beam vibration. Thus, the model of the structure for the lateral vibration can not be applied. Appropriate analysis model which can consider the inertia force of the beam is necessary when analyzing a structure for the vertical vibration. Modeling technique for the vertical vibration analysis of structures has been studied on this paper. It is recommeneded to use 2 or more elements for columns and to use 3 or more elements for beams when analyzing structures for vertical vibration induced by subway.

• 조명전기설비학회논문지
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• 제27권11호
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• pp.57-68
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• 2013

The market for distributed power generation based on renewable energy is increasing, particularly for standalone mini-grid applications in developing countries with limited energy resources. Stand-alone power systems (SAPS) are of special interest combined with renewable energy design in areas not connected to the electric grid. Traditionally, such systems have been powered by diesel engine generator sets (DEGS), but also hybrid systems with photovoltaic and/or wind energy conversion systems (WECS) are becoming quite common nowadays. Hybrid energy systems can now be used to generate energy consumed in remote areas and stand-alone microgrids. This paper describes the design, simulation and feasibility study of a hybrid energy system for a stand-alone power system. A simulated model is developed to investigate the design and performance of stand-alone hydrogen renewable energy systems. The analysis presented here is based on transient system simulation program (TRNSYS) with realistic ventilation load of a large store. Design of a hybrid energy system is site specific and depends on the resources available and the load demand.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.247-248
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• 2022

3D printer-based self-healing capsules have been proposed to heal cracks by enabling various structural designs, repeatable fabrication, and strength analysis of the capsules. The Fusion Deposition Modeling (FDM) method was used to design, analyze, and produce new self-healing capsules that are widely used at low cost. However, PLA extruded from FDM has low interlayer adhesion energy, and thus strength varies depending on the angle of load applied to the laminated layer and the concrete structure, thereby degrading the performance of the self-healing capsule. Therefore, in this paper, the structure of the capsule manufactured by the FDM PLA method has isotropic strength was designed. In addition, the fracture strength in the x, y, and z directions of the load applied through the compression test was analyzed. As a result, it was confirmed that the newly proposed capsule design has an isotropic fracture strength of 1400% in all directions compared to the existing spherical thin-film capsule.

• 한국지열·수열에너지학회논문집
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• 제13권3호
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• pp.1-8
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• 2017

Variable refrigerant flow (VRF) systems have recently attracted attention in many countries due to a variety of advantages over conventional system. Especially, the water-cooled VRF heat pump, including geothermal heat pump, is a system that accurately controls the flow rate of refrigerant for the improved efficiency under part load operation. This paper describe the process of generating the cooling and heating energy performance curve coefficients and performance expressions for modeling water cooled VRF system using EnergyPlus. Through this study, the process for generating performance curves can be implemented into EnergyPlus or other comparable building energy analysis tools for the long-term evaluation of heat pump under dynamic conditions.

• 대한건축학회논문집:계획계
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• 제34권3호
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• pp.23-34
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• 2018

Due to a waste of energy in korea, about 525,000 which are 75 percent of total buildings are at least 15 years old buildings that need remodeling. There are two current remodeling systems. One is a remodeling system to reduce a waste of resources from the reconstruction. The other is a green-remodeling system aimed to energy savings and reducing environmental costs. This study is to analyze quantitatively these current systems with respect to the cost-benefit caused by the life cycle and suggests the political and institutional implications through the interpretation of the results. For a quantitative analysis, we analyzed reducing maintenance costs and rent benefits with simulation by using opportunity costs, construction costs, plan costs and supervision costs as expense variables and using the reduced floor area ratio, institutional incentives, energy, water resources and certified emission reduction(CER) as benefit variables. As a result of the empirical study, the green-modeling was more beneficial in the field of environment such as the energy savings, however, the final benefits of remodeling which has no green building certification costs but more floor area ratio incentives were more economical. The green-remodeling system focused on reducing environmental costs and energy savings needs a equatable institutional incentive system.