• 한국공간구조학회논문집
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• 제18권2호
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• pp.69-78
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• 2018

In current research, it was attempted a preliminary design and evaluation of non-uniform ultra high-strength concrete (UHSC) truss members. UHSC used here has the compressive strength of 180 MPa, the tensile strength of 8 to 20 MPa, and the tensile strain after cracks up to 2%. By the three-dimensional finite element stress analysis as well as strut-tie approach on concrete solid beams, the non-uniform truss shape of UHSC truss was designed with the architectural esthetic concept. In a series of examples, to compare with conventional concrete members, the proposed UHSC truss members have advantages in capabilities of the slender design with minimum weight with high performances under transverse loadings as well as the aesthetically non-uniform design for spatial structures.

• 한국의류산업학회지
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• 제8권1호
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• pp.17-24
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• 2006

This research recognizes the importance of hotel and regular traditional restaurants contributing to tourism industry that goes along with demands of an era that considers traditional culture important, and focuses on searching for possibility by proposing direction of designs that traditional restaurant uniforms should aim. To achieve this study goal, by surveying the problems & preferences of the current uniform, over 60% of both the attendants & customers expected an improvement in the uniform. Most of the subjects wanted the improvement in design, followed by the improvement in functionality. Over 80% preferred traditional design or modernized design where traditional aspects were applied. Also, over 70% preferred a design where a pattern was applied. Among the patterns, over 80% of the subjects said that they prefer traditional patterns or modernized patterns where traditional aspects are applied. We admit that there are some limitations on this study, such as insufficient analysis & study on the attendants' action and their uniform, as well as limitations on restaurant selection. However, Through the study we expect that the Korea uniform can be differentiated from others, achieving World-class competitiveness.

• Structural Engineering and Mechanics
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• 제84권4호
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• pp.517-530
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• 2022

In re-assessing the Jacket-type fixed steel structures, the current standards often allow the simplicity of corrosion sections using local buckling or equivalent section approach to applying empirical formulae of frame stress and resistance analyses. However, those approaches can lead to significant errors for non-uniform corroded frames in a specific area, including force distribution, stress, and allowable strength of the tubular section, compared to the actual cases. This paper investigates a suitable approach to determine the actual stress on non-uniform corroded tubular frames under compression through the non-linear ABAQUS model by considering the effect of large deformation on the frame axis and the frame section. There are 3 scenarios of interest. In the 1st and 2nd scenarios with simple corrosion cases, the stress ratios using the numerical model and theoretical formulae correspond to the calculation of allowable strength reduction ratios in standards. However, scenario 3, which describes non-uniform corroded sections based on survey data, provides considerable differences in results. Therefore, it proves the reliable and effective results when using this method to analyze the resistance of the actual corroded section in the Jacket platforms.

• 디자인학연구
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• 제18권3호
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• pp.105-116
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• 2005

본 연구는 전통 문화상품으로 잠재력을 지니고 있는 씨름의 이미지 구축에 관한 복식 연구로서, 씨름복의 체계화 및 시각화에 관한 방안제시, 그리고 씨름복 디자인 개발에 관한 기초 기반연구를 목적으로 하고 있다. 따라서 기초적인 부분으로는 씨름복의 역사성에 대한 탐구로 세계 씨름과 우리나라의 씨름을 비교 고찰해 보았으며, 씨름복에 관한 변천사에 관하여 탐구해 보았다. 또한 실질적인 부분으로는 현행 씨름 및 씨름복에 관한 기준에 대하여 그 내용을 숙지하고, 디자인 기반 연구로서 씨름복이 갖는 미학적인 부분을 크게 네 가지 항목으로 분류하여 첫째 전통성과 독창성, 둘째 유온성과 적합성, 셋째 상징성과 장식성, 넷째 다양성과 통일성으로 그 내용을 체계화하였다. 결론적으로 씨름복 디자인 기획에 있어 가장 중요한 부분은 상기에서 제시한 미학적 부분을 토대로 일관된 컨셉을 시각화하는데 있다. 이번 연구는 씨름복에 관한 미학적 부분의 이론 연구로서, 디자인 컨셉 설정 및 디자인 전개의 지침을 제시하는데 의의를 지니며, 향후 추진될 전통 문화 복식 디자인의 기획에 관한 기반연구였다는 점에 그 의미를 둔다.

• 한국표면공학회지
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• 제49권5호
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• pp.423-430
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• 2016

In this study, we investigated the corrosion damage characteristics of steel for offshore wind turbine tower substructure using an accelerated electrochemical test. The galvanostatic corrosion test method was employed with a conventional 3 electrode cell in natural sea water, and the steel specimen was served as a working electrode to induce corrosion in an accelerated manner. Surface and cross-sectional image of the damaged area were obtained by optical microscope and scanning electron microscope. The weight of the specimens was measured to determine the gravimetric change before and after corrosion test. The result revealed that the steel tended to suffer uniform corrosion rather than localized corrosion due to active dissolution reaction under the constant current regime. With increasing galvanostatic current density, the damage depth and surface roughness of surface was increased, showing approximately 25 times difference in damage depth between the lowest current density ($1mA/cm^2$) and the highest current density ($200mA/cm^2$). The gravimetric observation showed that the weight loss was proportionally increased with increment of current density that has 75 times different according by experimental conditions. Consequently, uniform corrosion of the steel specimen was conveniently induced by the electrochemically accelerated corrosion technique, and it was possible to control the extent of the corrosion damage by varying the current density.

• 한국전기전자재료학회논문지
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• 제20권7호
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• pp.626-630
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• 2007

The AC loss is an important issue in the design of the high temperature superconductor (HTS) power cables and fault current limiters. In these applications, a cylindrical HTS conductor is often used. In commercialization of these apparatuses, AC loss is a critical factor but not elucidated completely because of complexities in its measurement, e.g. non-uniform current distribution and phase difference between currents flowing in an individual HTS tape. We have prepared two cylindrical conductors composed of a Bi-2223 tape with different critical current density. In this paper, the AC loss characteristics of the conductors have been experimentally investigated and numerically analyzed. The result show that the measured losses for two conductors are not dependent on both arrangements and contact positions of a voltage lead. This implies that most of loss flux is only in the conductors. The loss for the Bi-2223 conductor with low critical current density is in good agreement with the calculated loss from Monoblock model, whereas the loss measured for the Bi-2223 conductor with high critical current density doesn't coincide with the loss calculated from the Monoblock model. The measured loss is also different from numerically calculated one based on the polygon model especially in low transport current.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.82-84
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• 2003

In case contact between point of contacts is not achieved well, contact resistance is grown, and by current concentration at current conducting contacts can weld. In order to decrease contact resistance between contacts in case of busbar, installing spring between fixed contact and moving contact. and then force on faying surface of contacts increase and contact resistance decrease. But, in case increase force of spring to widen contact area, operating force moving contact can grow, on the contrary force of spring is small, contact resistance becomes low. Therefore, need to optimize force and number of spring. position, and also need to examine force change on contact surface at point of contact moving. In this paper, dynamic kinetics analysis for force on faying surface of contacts is performed at unsteady state. It is showed to not uniform force on surface between contacts, and we can got more uniform force by means of change spring position.

• International Journal of Naval Architecture and Ocean Engineering
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• 제1권2호
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• pp.101-107
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• 2009

The VIV (Vortex-Induced Vibration) analysis of a flexible cylindrical structure under locally strong shear flow is presented. The model is made of Teflon and has 9.5m length, 0.0127m diameter, and 0.001m wall thickness. 11 2-dimensional accelerometers are installed along the model. The experiment has been conducted at the ocean engineering basin in the University of Tokyo in which uniform current can be generated. The model is installed at about 30 degree of slope and submerged by almost overall length. Local shear flow is made by superposing uniform current and accelerated flow generated by an impeller. The results of frequency and modal analysis are presented.

• Elastomers and Composites
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• 제57권4호
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• pp.147-156
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• 2022

In this study, we chose a flat die to optimize a general die geometry. The optimization was aimed at obtaining a uniform velocity distribution across the exit of the die. For the optimization, the input and output design parameters were randomly computed, and response surfaces were generated to obtain statistical data for the minimum and maximum sensitivities computed during optimization. Subsequently, object functions with constraints were numerically computed to obtain the minimum errors in the velocity difference (i.e., variable "Outp" in this study). Finally, we obtained the candidate optimized dataset. Note that the current numerical computations were simultaneously conducted for an entire extruder, i.e., screw plus die. The numerical outlet velocity distributions in the modified die geometry tended to be much more uniform than the conventional distributions in the current optimization processes for this specific flat die.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 추계학술대회
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• pp.549-550
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• 2021

본 논문에서는 다양한 돌연변이 전략을 인식하기 위해 MUDE (Uniform Local Search)를 사용한 다중 인구 차등 진화 알고리즘을 제안한다. MUDE에서 집단은 진화 비율(DE/rand/1 및 DE/current-to-rand/1)에 따라 서로 다른 돌연변이 전략을 수행하는 다른 집단 크기를 가진 여러 하위 집단으로 나뉜다. 인구의 다양성을 개선하기 위해 정보는 소프트 아일랜드 모델에 의해 하위 인구 간에 마이그레이션된다.