• 한국의상디자인학회지
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• 제25권2호
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• pp.97-110
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• 2023

The purpose of this study is to develop 3D pattern textile design of traditional Jogakbo motifs and fashion products using it. As a research method, first, through literature review, the three-dimensional representation of geometry on a plane with Jogakbo, design cases were examined. Second, through a survey, the purchase perception and design preference of Jogakbo cultural products was analyzed. Third, based on the results of the survey on color and print, the 3D pattern design for each type of Jogakbo is printed, and then textile fashion cultural products were developed. The results of this study are as follows. First, the reason why the public was not attracted to the purchase of cultural products was disatisfaction with practicality, unsuitable preference, price adequacy, aesthetics, and originality. Therefore, it was analyzed that quality, practicality, price, carry-on storage harmony and manageability, as well as aesthetic design were important factors for consumers. Second, the stereoscopic space on the plane expanded the two-dimensional plane space by forming a cube through the division and dissolution of geometry could be visualized using color expression of cubes of different brightness depending on the direction of light. Third, Jogakbo had eight types consisting of four detailed forms and three arrangement methods. The 3D pattern design could be developed through regular disolution and stereoscopic construction using Jogakbo's representative images for each type. In addition, it was found that it was easy to produce Jogakbo fashion products suitable for modern people through 3D pattern digital textile printing applying traditional colors.

• 한국산학기술학회논문지
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• 제14권2호
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• pp.955-961
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• 2013

본 연구는 친환경 건축의 대안으로 부각되고 있는 한옥의 열환경 평가를 수행하기 위하여 한옥을 구성하고 있는 건축요소의 전열 메카니즘을 규명하기 한옥건축부재의 규격화와 모델링을 통하여 열환경을 평가하였다. 최근 친환경 건축, 생태건축의 모델로 일반의 한옥 선호도는 높아지고 있으나, 한옥의 우수성이 정성적으로만 평가되고 있다. 이에 한옥의 건축재료 및 형태와 같은 건축요소를 고려, 한옥 건축요소의 Geometry를 작성하여 솔리드 모델을 구축하고, 열환경 평가의 도구로써 CFD를 적용하여 한옥의 실내 열환경을 평가하고자 하였다. 본 연구에서는 복잡한 형태의 Geometry 작성이 가능한 CATIA와 환경 시물레이션 Code인 FLUENT 등의 상용 Code를 활용함으로써 연구의 신뢰성을 높이고자 하였다. 본 연구는 일차적으로 서울지방에 건축된 한옥의 기준모델을 설정하여 벽, 천정, 바닥, 창호 등 건축요소의 부위별 형태를 고찰하고, Geometry작성의 입력자료로 사용하기 위하여 각 부위별 치수체계를 구축하였다. 건축요소의 부위별 각각의 형태를 솔리드 모델로 구축하기 위하여 단계별로 벽, 천정, 바닥, 창호 등에 관한 건축요소의 Geometry를 모델링하여 CFD 입력자료로 활용하여 열환경 시물레이션을 수행하였다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.464-468
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• 2003

A general program of three dimensional profile design of impellers for centrifugal/fixed-flow compressors is successfully commercialized using Bezier curves and quasi-3D flow analysis methods. Control points for meridional hub and shroud contours and blade camberline angles are arbitrarily changed to give smooth Bezier curves. With specified blade normal thicknesses, contructed geometry is instantly analyzed using flow analysis methods to be checked.

• 한국전산유체공학회지
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• 제18권3호
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• pp.26-33
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• 2013

In the present study, unsteady flow simulations of a variable geometry nozzle were conducted using a two-dimensional flow solver based on hybrid unstructured meshes. The variable geometry nozzle is used to achieve efficient performances of aircraft engines at various operating conditions. To describe the motion of the variable geometry nozzle, an algebraic method based on the basis decomposition of normal edge vector was used for the deformation of viscous elements. A ball-vertex spring analogy was used for inviscid elements. The aerodynamic data were obtained for a range of nozzle pressure ratios, and the validations were made by comparing the present results with available experimental data. The unsteady nozzle flows were simulated with an oscillating diverging section and a converging-diverging section. It was found that the nozzle performances are influenced by the nozzle exit flow characteristics, mass flow rate, as well as unsteady effects. These unsteady effects are shown to behave differently depending on the frequency of the nozzle motion.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 가을 학술발표회 논문집
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• pp.457-464
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• 1999

The active earth pressure on the retaining wall is reduced by 3-Dimensional effects of the ground. Therefore, the test was focused on reducing the earth pressure on the retaining wall by inserting the vertical reinforcement in the backfill ground to develope the 3-Dimensional effects. Model tests in sand were peformed to measure the 3-Dimensional effects of the vertical reinforcement on the active earth pressure and its distribution and results were compared with the theories. The size of the vertical reinforcement, the geometry of the backfill space, and the wall friction of vertical reinforcement were varied. It was observed that the active earth pressure and its distribution on the underground structure were affected by the size of the vertical reforcements and wall friction.

• Nuclear Engineering and Technology
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• 제45권5호
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• pp.613-624
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• 2013

Multi-dimensional two-phase phenomena occur in many industrial applications, particularly in a nuclear reactor during steady operation or a transient period. Appropriate modeling of complicated behavior induced by a multi-dimensional flow is important for the reactor safety analysis results. SPACE, a safety analysis code for thermal hydraulic systems which is currently being developed, was designed to have the capacity of multi-dimensional two-phase thermo-dynamic phenomena induced in the various phases of a nuclear system. To validate the performance of SPACE, a two-dimensional two-phase flow test was performed with slab geometry of the test section having a scale of $1.43m{\times}1.43m{\times}0.11m$. The test section has three inlet and three outlet nozzles on the bottom and top gap walls, respectively, and two outlet nozzles installed directly on the surface of the slab. Various kinds of two-dimensional air/water flows were simulated by selecting combinations of the inlet and outlet nozzles. In this study, two-dimensional two-phase void fraction profiles were quantified by measuring the local gap impedance at 225 points. The flow conditions cover various flow regimes by controlling the flow rate at the inlet boundary. For each selected inlet and outlet nozzle combination, the water flow rate ranged from 2 to 20 kg/s, and the air flow rate ranged from 2.0 to 20 g/s, which corresponds to 0.4 to 4 m/s and 0.2 to 2.3 m/s of the superficial liquid and gas velocities based on the inlet port area, respectively.

• 한국정밀공학회지
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• 제22권11호
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• pp.182-189
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• 2005

The human knee joint is the intermediate joint of the lower limb that is the largest and most complex joint in the body. Understanding of joint-articulating surface motion is essential for the joint wear, stability, mobility, degeneration, determination of proper diagnosis and so on. However, many studies analyzed the passive motion of the lower limb because of the skin marker artefact and some studies described medial and lateral condyle of a femur as a simple sphere due to the complexity of geometry. Thus, in this paper, we constructed a three-dimensional geometric model of the human knee from the geometry of its anatomical structures using non-uniform B-spline surface fitting as a study for the kinematic analysis of more realistic human knee model. In addition, we developed and verified 6-DOF contact model of the human knee joint using $C^2$ continuous surface of the inferior region of a femur, considering the relative motion of shank to thigh during locomotion.

• 설비공학논문집
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• 제13권5호
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• pp.398-410
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• 2001

The flow and heat transfer characteristics for three-dimensional mixed convection flows in a radiator flat tube with U--shaped grooves are analyzed numerically. The flow and temperature fields are calculated by using the modified SIMPLE algorithm for irregular geometry. One tube specification among the various flat tube exchangers is recommended by considering the heat transfer and pressure drop. The effects of variation of coolant flow conditions and external air conditions on the flow and the thermal characteristics for the selected tube are investigated. the results show that inlet velocity of coolant flow is the very important factor in heat transfer and pressure drop, and top side is better position than the others as fin cleave to tube.

• ETRI Journal
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• 제44권5호
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• pp.816-825
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• 2022

Nondestructive testing, which can monitor a product's interior without disassembly, is becoming increasingly essential for industrial inspection. Computed laminography (CL) is widely used in this application, as it can reconstruct a product, such as a printed circuit board, into a three-dimensional (3D) high-magnification image using X-rays. However, such high-magnification scanning environments can be affected by minute vibrations of the CL device, which can generate motion artifacts in the 3D reconstructed image. Since such vibrations are irregular, geometric corrections must be performed at every scan. In this paper, we propose a geometry calibration method that can correct the geometric information of CL scans based on the image without using geometry calibration phantoms. The proposed method compares the projection and digitally reconstructed radiography images to measure the geometric error. To validate the proposed method, we used both numerical phantom images at various magnifications and images obtained from real industrial CL equipment. The experiment results confirmed that sharpness and contrast-to-noise ratio (CNR) were improved.

• 터널과지하공간
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• 제22권2호
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• pp.93-105
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• 2012

균열암반의 등가역학적 물성을 수치해석적으로 결정할 때 2차원 및 3차원 해석을 비교하였다. 수직균열모델과 암반균열망(DFN) 모델이 균열암반의 형상으로 이용되었으며 3차원 모델으로부터 다양한 방향으로 2차원 모델을 절단하여 역학적 물성을 비교하였다. 본 연구의 지질데이터는 영국 셀라필드 지역의 자료를 기본으로 사용하였다. 직교균열모델에서는 컴플라이언스텐서의 변환을 이용한 해석적 방법이 물성결정을 위해 이용되었으며 암반균열망모델에서는 수치실험이 실시되었다. 2차원 모델에서는 균열이 항상 모델평면과 직교한다고 가정하기 때문에 탄성계수는 항상 3차원보다 크게 계산이 되었다. 2차원 해석에서의 포아송비는 3차원 해석보다 큰 값을 나타내는 경향이 있었으나 반대의 경향도 관찰되었다. 본 논문은 3차원 형상을 단순화시켜 사용하는 2차원 해석의 한계를 정량적으로 고찰하였다는데 의의가 있다.