• International Journal of Naval Architecture and Ocean Engineering
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• 제2권4호
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• pp.217-222
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• 2010

Since 1980's, optimum design techniques for ship structural design have been developed to the preliminary design which aims at minimum weight or minimum cost design of mid-ship section based on analytic structural analysis. But the optimum structural design researches about the application for the detail design of local structure based on FEA have been still insufficient. This paper presents optimization technique for the detail design of a racing motor boat. To improve the performance and reduce the damage of a real existing racing boat, direct structural analyses; static and non-linear transient dynamic analyses, were carried out to check the constraints of minimum weight design. As a result, it is shown that the optimum structural design of a racing boat has to be focused on reducing impulse response from pitching motion than static response because the dynamic effect is more dominant. Optimum design algorithm based on nonlinear finite element analysis for a racing motor boat was developed and coded to ANSYS, and its applicability for actual structural design was verifed.

• Journal of Sport and Applied Science
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• 제3권1호
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• pp.1-14
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• 2019

Numerous types of sporting events have been hosted in Korea during the last decades. Sport events produce various types of data, and there is a clear necessity of storing and utilizing this information. From this background, the purpose of this study is to draw complex sports categories from international sport events life cycles in order to categorize standards of knowledges management system. This study utilized qualitative methods: expert groups discussion for overall life cycle steps and in-depth interviews for detail life cycle steps. The results show that there are several life cycle steps: bidding, preparation, operation, evaluation, post management steps. To be more specific, for the bidding step, there are check, plan, implementing detail phase; and the preparation step is based on event preparation Basis Build, event preparation implementation, test and supplementation phases. For the operation step, event operation system switch, event operation during the period, finish operation phases are deducted. Evaluation and post management step do not have detail phases. Efforts to store and utilize knowledge can be one of the starting points to make the operation of sport events efficiently.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2002년도 추계학술대회 논문집
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• pp.163-170
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• 2002

Terrain surfaces have to be modeled in very detail and wheel-surface contacting geometry must be well defined in order to obtain proper ground-reaction and friction forces for realistic simulation of off-road vehicles. Delaunay triangulation is one of the most widely used methods in modeling 3-dimensional terrain surfaces, and T-search is a relevant algorithm for searching resulting triangular polygons. The T-search method searches polygons in successive order and may not allow real-time computation of off-road vehicle dynamics if the terrain is modeled with many polygons, depending on the computer performance used in the simulation. In order to accelerate the searching speed of T-search, a terrain database of triangular polygons is modeled in multi-levels by adopting the LOD (Level of Detail) method used in realtime computer graphics. Simulation results show that the new LOD search is effective in shortening the required computing time. The LOD search can be even further accelerated by introducing an NN (Neural Network) algorithm, in the cases where a appropriate range of moving paths can be predicted by cultual information of the simulated terrain, such as lakes, houses, etc.. Numerical tests show that LOD-NN search almost double the speed of the original T-search.

• 한국강구조학회 논문집
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• 제23권1호
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• pp.113-124
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• 2011

본 연구는 BIM 기반의 건축구조설계 업무 프로세스에서 활용 가능한 철골 구조물의 구조해석모델과 기본상세모델의 상호운용성에 관한 것으로, 구조설계 업무를 지원하는 구조해석 소프트웨어와 상세모델링 및 도면작성 업무를 지원하는 BIM 소프트웨어 사이의 정보 교환을 수행할 수 있는 인터페이스 모듈의 개발에 관한 것이다. 인터페이스 모듈은 BIM의 상호운용성을 위한 정보 교환 방식 중 직접 연결 방식을 적용하였으며, 상용 BIM 어플리케이션 벤더에서 제공하는 OpenAPI를 이용하여 닷넷 프레임워크 개발환경을 통해 개발하였다. 개발된 인터페이스 모듈의 검증을 위해 예제 모델을 선정하여 구조해석모델로부터 상세모델링을 수행하기 위한 기본상세모델의 생성을 수행하였으며, 수행 과정을 기존 프로세스와 인터페이스 모듈을 적용한 연구 프로세스로 구분하여 비교, 분석함으로써 인터페이스 모듈의 효율성을 검증하였다.

• International Journal of Concrete Structures and Materials
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• 제9권1호
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• pp.61-67
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• 2015

The concept of horizontal shear connection utilization on wood-concrete beams intends to be an alternative connection detail for composite wood-concrete decks. The volume of sawn-wood is over three times more expensive than concrete, in Brazil. In order to be competitive in the Brazilian market we need a composite deck with the least amount of wood and a simple and inexpensive connection detail. This research project uses medium to high density tropical hardwoods managed from the Brazilian Amazon region and construction steel rods. The beams studied are composed of a bottom layer of staggered wood boards and a top layer of concrete. The wood members are laterally nailed together to form a wide beam, and horizontal rebar connectors are installed before the concrete layer is applied on top. Two sets of wood-concrete layered beams with horizontal rebar connectors (6 and 8) were tested in third-point loading flexural bending. The initial results reveal medium composite efficiency for the beams tested. An improvement on the previously conceived connection detail (set with six connectors) for the composite wood-concrete structural floor system was achieved by the set with eight connectors. The new layout of the horizontal rebar connectors added higher composite efficiency for the beams tested. Further analysis with advanced rigorous numerical Finite Element Modeling is suggested to optimize the connection parameters. Composite wood-concrete decks can attend a large demand for pedestrian bridges, as well as residential and commercial slabs in the Brazilian Amazon.

• 항공우주기술
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• 제8권2호
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• pp.26-32
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• 2009

위성영상의 융합에 있어, 가장 중요한 점은 전정영상의 공간적 세밀함과 다중분광영상의 분광정보 모두를 보존하는 것이다. 다양한 영상융합 기법 중에서, IHS 변환을 이용한 융합기법은 폭넓게 사용되고 있으며, 계산과정이 매우 단순하다는 장점을 갖고 있다. 본 연구에서는, fast IHS 변환과 trade-off 파라미터 $\alpha^i$를 이용한 융합기법을 제안한다. 제안한 융합 기법은 분광 ERGAS와 공간 ERGAS의 평가를 통하여, 융합영상에서 분광정보와 공간적 세밀함 사이의 trade-off 최적화를 가능하게 한다. IKONOS 영상의 실험결과, 제안한 기법은 기존의 fast IHS 변환을 이용한 융합기법에 비해 공간적 세밀함과 분광정보의 보존측면에서 더 효과적임을 확인할 수 있었다.

• 대한기계학회논문집A
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• 제33권8호
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• pp.842-848
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• 2009

Fatigue failures are often occurred at welded joints where stress concentrations are relatively high due to the joint geometry. Although employing good detail design practices by upgrading the welded detail class enables to improve the fatigue performance, in many cases, the modification of the detail may not be practicable. As an alternative, the fatigue life extension techniques that reduce the severity of the stress concentration at the weld toe region, remove imperfections and introduce local compressive welding residual stress, have been applied. These techniques are also used as definite measures to extend the fatigue life of critical welds that have failed prematurely and have been repaired. In this study, a hammer peening procedure for using commercial pneumatic chipping hammer was developed, and the effectiveness is quantitatively evaluated. The pneumatic hammer peening makes it possible to give the weld not only a favorable shape reducing the local stress concentration, but also a beneficial compressive residual stress into material surface. In the fatigue life calculation of non-load carrying cruciform specimen treated by the pneumatic hammer peening, the life was lengthened about ten times at a stress range of 240MPa, and fatigue limit increased over 65% for the as-welded specimen.

• 복합신소재구조학회 논문집
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• 제5권4호
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• pp.24-35
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• 2014

An experimental study on the structural behavior of connection types between approach slab and integral abutment has been done for three typical bar connections. Typical hinge style reinforcing bar detail for its connection is preferred in order to accommodate rotation of the approach slab among engineers. However, the straight horizontal bars can be used as connection detail accomodate structural capacity. Total six specimens with three types of rebar detail are tested for direct tensile and bending load. The characteristic structural behaviors are carefully monitored and all the strain gauge data obtained are analyzed. It is shown that the structural performance of all the specimens well exceed its design allowance. Several design suggestions are given based on careful reviews on the experiment.

• 한국BIM학회 논문집
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• 제7권4호
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• pp.8-20
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• 2017

When it comes to set up the BIM through the reverse engineering, the level of detail(LoD) required for finalized outcomes is different from each purpose. Therefore, it is necessary to establish some concrete criteria which describe the definition of LoDs on 3D modeling for the purpose of each reverse engineering. This research shows the criteria of the 1) positional accuracy, 2) generalization level, 3) scale level, 4) scope of description, and 5) the area available for application by classifying LoD from 1 to 6 on 3D modeling for each purpose of reverse engineering. Moreover, through applying those criteria for the 3D point cloud dataset of building made by terrestrial LiDAR, this research finds out the working hour of 3D modeling of reverse engineering by each LoDs according to defined LoD criteria for each level. It is expected that those findings, how those criteria of LoD on reverse engineering are utilized for modeling-workers to decide whether the outcomes can be suitable for their budget, applicable fields or not, would contribute to help them as a basic information.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.259-261
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• 2002

KEPCO(Korea Electric Power Corporation) has been management alone before some time. However through the electrical industry reorganization generation and KPX(Korea Power Exchange) were separated on 2001. A marketing and distribution part will be separated in the future. While many problem for appear in future. how to management for power system network is important. unfortunallity, electrical power industry is starting point right now. Thus, detail data is incomplete for this field and detail research for this field is required with distribution reorganazation. In this paper suggest for customer interruption cost compute method to establish a standard. The standard is need to security operation of power system network. The customer interruption cost compute method necessity of customer interruption cost compute method is minimizing process for total cost. As final total cost compute through the interruption cost compute, we can recognize investment point exactly. We cited foreign survey questions, because exactly matched survey questions for in the country circumstance is not exist. And process to survey performance suggest after modify for match in the country circumstance. Survey questions that suggested fer this paper are classified five categories. This paper suggests to detail survey questions and survey method before survey and suggest to how to customer interruption compute when survey data is ensured. Moreover this paper suggest to average interruption cost compute for residential customer using statistical method.