• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.195-196
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• 2013

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권2호
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• pp.270-287
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• 2015

According to the increase of the operating cost and material cost of a ship due to the change of international oil price, a demand for the lightening of the ship weight is being made from various parties such as shipping companies, ship owners, and shipyards. To satisfy such demand, many studies for a light ship are being made. As one of them, an optimal design method of an existing hull structure, that is, a method for lightening the ship weight based on the optimization technique was proposed in this study. For this, we selected a hatch cover of a bulk carrier as an optimization target and formulated an optimization problem in order to determine optimal principal dimensions of the hatch cover for lightening the bulk carrier. Some dimensions representing the shape of the hatch cover were selected as design variables and some design considerations related to the maximum stress, maximum deflection, and geometry of the hatch cover were selected as constraints. In addition, the minimization of the weight of the hatch cover was selected as an objective function. To solve this optimization problem, we developed an optimization program based on the Sequential Quadratic Programming (SQP) using C++ programming language. To evaluate the applicability of the developed program, it was applied to a problem for finding optimal principal dimensions of the hatch cover of a deadweight 180,000 ton bulk carrier. The result shows that the developed program can decrease the hatch cover's weight by about 8.5%. Thus, this study will be able to contribute to make energy saving and environment-friendly ship in shipyard.

• 건축역사연구
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• 제22권6호
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• pp.23-34
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• 2013

The purpose of this study is to look into the weight-lightening phenomenon of the roof structure of some Hanok(韓屋), the Korean traditional houses found from the survey on the distribution and actual state of urban traditional houses existing in the whole region of Jung-gu, Daegu, Korea. As a result of judging from the pre-test of building registers for the research area, approximately 5,000 wood structure houses were found. A field data survey based on these findings showed that there are 1,752 Hanok houses. And the further classification of the Korean traditional houses by roof structure type shows that about 35% of them underwent weight lightening. While this kind of light-weight Hanok is different from the concept of traditional Hanok, they also show the survival method of Hanok that reflects the economical and technological phases of that period. It is expected that deeper understanding on the urban traditional houses will be possible through carrying out in-depth researches on techniques of the light-weight roof structure of the urban traditional houses that are supposed to have functioned as dwellings as commercial products.

• 한국생산제조학회지
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• 제21권6호
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• pp.920-925
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• 2012

A study of vehicle weight lightening has been progressed to reduce the fuel consumption. In this paper, the body floor in an EV (Electric Vehicle) bus has been applied by composites as CFRP and GFRP. In order to analyse a various reliability and safety, an experiment and FEM analysis was carried out to obtain weight lightening. Especially, the joint. An effective design is obtained through an experiment as well as FEM analysis. Results of stress analysis of GFRP material showed twice as much displacement than those of CFRP material. Among three kinds of joint methods, the bond joint method is occurred to a substantial shape change in the body and floor. It is found that the rivet joints are fairly suitable for stress sustaining capability.

• Spatial Information Research
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• 제21권6호
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• pp.1-9
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• 2013

최근 건설정보가 CAD에서 BIM으로 전환되고 있으며, GIS 분야는 기존 실외공간에서 실내공간으로 확장되고 있다. 이러한 상황에서 건설정보를 GIS와 연계하여 계획 설계 시공의 건설단계는 물론 건설 후 유지관리 및 운영 서비스 단계에서 지속적으로 활용할 필요성이 커지고 있다. 이를 위하여 건설정보와 공간정보의 유기적 결합을 통한 BIM-GIS 상호운용 플랫폼을 구축함에 있어 대용량 3차원 공간객체의 효율적 표현은 필수적인 요소이다. 본 연구에서는 대용량 공간객체를 표현함에 있어 각 레벨별 공간객체와 이에 따르는 텍스처를 효과적으로 생성할 수 있도록 BIM 데이터와 GIS 공간 데이터의 연계활용을 위한 공간데이터 LOD를 설계하고 이를 기반으로 기존의 대용량 공간객체를 경량화할 수 있는 알고리즘을 개발하였다.

• 한국기계가공학회지
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• 제12권4호
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• pp.55-60
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• 2013

In this study, mechanical properties of versatile light weight plywood(manufacturing using piercing) are studied. A credibility evaluation was carried out for different perforation patterns including octagonal shape, rectangular shape and circular shape. A static structural analysis is conducted to find the stresses produced. Circular perforations are found to have better strength to weight ratio. Results of each type of perforation are discusses and compared.

• 한국소음진동공학회논문집
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• 제23권12호
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• pp.1045-1055
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• 2013

It is true that the dependency on import is currently high in case of the safety checkup system of domestic airplanes, and it is at the point of time that localization of HUMS for small airplanes is required. In this study, the design factors were selected for the lightweight of HUMS for small airplanes by using Pro-Engineer which is a design tool and Abaqus. 9 models were made through experiment plans with Taguchi method for this, and the each model for weight lightening was selected through vibration analysis and shock analysis while in operation with experiment profile values. After fabricating HUMS, it was verified that as a result of experiment with the same profile values as the analysis, there was similarity between the analyzed values and values of the experiment. As a result of performing weight lightening which is the purpose of the study, electronic performance for small airplanes is assured and a design plan reducing 15 % weight compared to the targeted weight was deduced. Besides, it could be verified that the light weight model satisfied the maximum allowable displacement value of PCB[printed circuit board] and accordingly satisfied electronic properties of HUMS. In this study, the reliability of a product was certified through the result of an experiment on ground. If the reliability of HUMS were verified through a test flight in the future, it is considered that it would make a big contribution to localization of aerospace electronic equipment.

• Journal of Welding and Joining
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• 제31권4호
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• pp.1-6
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• 2013

Nowadays, the weight lightening of automotive is required as conserving the environment has become a major worldwide issue. To solve this issue, various researches for the use of light materials(Alalloy, Mgalloy)and ultra high strength steel as substitutes of the current structural material have been carried out. Application of laser stitch welding to the assembly of automotive produces improvement in strength, lightening of body, higher fuel efficiency, lower production cost as well as reduction in assemble line due to its fast welding speed, superior accessible and weld quality. This process overcomes the shortcomings of the current resistance spot welding such as high electricity consumption, electrode replacement, and economical, technical limitation in design and production method of automotives.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.141-142
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• 2015

This literature study is focused on the improvement of lightweight concrete in perspective of foaming agent. Lightweight concrete is the cured concrete as putting required amount of foaming agent to slurry which is a mixture of a certain amount of cement, sand, and water. It has lower density than general concrete, because foaming agent disintegrates numerous bubbles evenly and independently. Thus, it is capable of lightening the weight and great for sound absorption and insulation, In foreign countries, studies for structural lightweight concrete mainly of tunnel grouting and weight lightening of heavy structures are going along actively. Domestically, exterior panel and ALC blocks are alternatively used for flooring. Therefore, this research consider improvement of lightweight concrete in perspective of foaming agent with foundation study.

• 한국철도학회논문집
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• 제19권2호
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• pp.135-144
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• 2016

분기기 거더 경량화는 제작비 감소 및 제작의 용이함을 위해 필수적이다. 자기부상열차용 3방향 분기기 경량화를 위한 설계변수는 부상안정성과 관련 있기 때문에 신중히 결정되어야 한다. 도시형 자기부상열차는 대차가 레일을 감싸는 구조로 되어 있기 때문에 거더 높이 변경을 통해서 경량화가 가능하다. 실제 테스트베드에서 반복 주행시험을 통해 안정성을 확보해야 하지만 공간적, 비용적 제한에 의해 여러 거더 높이의 테스트베드 제작은 불가능하며 이를 보완하기 위한 설계 파라미터 연구는 필수적이다. 본 논문에서는 자기부상열차 주행 시 3방향 분기기 경량화에 따른 부상안정성을 고려한 설계 파라미터 연구에 그 목적이 있다. 이를 위해 분기기 거더 높이 변경을 통해 경량화하였고 모달 중첩법을 이용하여 유연체로 모델링 하였다. 유연체 분기기와 자기부상열차 동역학 모델과의 연동해석을 통해 차량의 통과속도, 횡 공극, 부상 공극을 비교하고 부상안정성에 미치는 영향을 분석하였다. 이를 통해 거더높이와 부상안정성과의 상관관계에 대해 분석하였다. 본 논문의 연구 결과는 자기부상열차용 분기기 설계에 활용 가능할 것이다.