• 소성∙가공
• /
• 제25권5호
• /
• pp.319-324
• /
• 2016

Recently, the roll forming process is one of the most widely used processes for manufacturing automotive part. In this study, flower patterns of roll forming process were designed to manufacture an ultra high strength bumper beam using the finite element analysis. Three types of flower patterns such as the basic type, the rotation type and the split type were designed based on the constant arc length forming method using the design software, UBECO Profil. Finite element analysis was performed to evaluate the suitability of designed flower patterns in terms of the longitudinal strain and the bow defect. The analytical results show that the split type represents more uniform longitudinal strain distributions and a good dimensional accuracy than other types of flower patterns.

• 한국해안해양공학회지
• /
• 제12권4호
• /
• pp.157-167
• /
• 2000

한국해양연구소는 1998년에 이어도 종합해양과학기지의 기본설계를 수행한 바 있으며 심해 설계파에 Morison 식과 Stream function 이론을 적용하여 설계파력을 결정한 바 있다. 본 연구에서는 삼차원 수리모형실험 통하여 이어도 해역에서의 파랑전파를 모의하였으며, 구조물의 파력 및 Air gap를 계측하고 이들을 SACS 프로그램의 계산치와 비교함으로써 기본설계 값들의 타당성을 검토하였다. 그 결과, 시도된 4개의 심해파향 중에서 SSW, S, SE계열의 파향에 대해서는 계측치가 SACS 계산치 보다 작게 나타났다. 그러나, 유일하게 구조물에 미치기 전에 쇄파되는 NNW계열의 파향에서는 전반적으로 SACS 계산치를 상회하였으며, 그방향성 흐름과 파가 복합되어 있는 경우와 매우 유사한 파력변화를 보여주었다. 구조물의 Air gap은 모든 심해파향에 대하여 계측치가 기본설계치보다 작은 것으로 나타났다.

• 한국의류학회지
• /
• 제47권1호
• /
• pp.123-136
• /
• 2023

To develop smart sportswear capable of measuring biometric data, we created a close-fitting pattern using two- and three-dimensional (2D and 3D, respectively) methods. After 3D virtual fitting, the tightness of each pattern was evaluated using image processing of contact points, mesh deviation, and cross-sectional shapes. In contact-point analysis, the 3D pattern showed high rates of contact with the body (84.6% and 93.1% for shirts and pants, respectively). Compared with the 2D pattern, the 3D pattern demonstrated closer contact at the lower chest, upper arm, and thigh regions, where electrocardiography and electromyography were primarily carried out. The overall average gap was also lower in the 3D pattern (5.27 and 4.66 mm in shirts and pants, respectively). In the underbust, waist, thigh circumference, and mid-thigh circumference, the cross-section distance between clothing and body was showed a statistically significant difference and evenly distributed in the 3D pattern, exhibiting more closeness. The tightness and fit of the 3D smart sportswear sensor pattern were successfully evaluated. We believe that this study is critical, as it facilitates the comparison of different patterns through visualization and digitization through 3D virtual fitting.

• 패션비즈니스
• /
• 제20권4호
• /
• pp.153-171
• /
• 2016

With the advent of smart clothing for health care and sports, the sophisticated designs with curved seams are drawing attention. One of the problems in those clothing is to determine the design curves in 2D pattern, such that it corresponds to the lines on the intended 3D body. Moreover, the difficulty increases when the original pattern needs to be changed for various sizes and body types. We compare two methods of pattern enlargement in this paper: one is the offset/projection type, and the other is the split grading type. For the enlarged pattern with offset/projection type, the 3D surface offset was first adopted to transform the standard lower body to the target larger size; next, the design lines were projected to the new 3D surface, following which the 3D pattern was developed from the newly transformed 3D surface. In the second method, the enlarged pant patterns were developed by the split grading method. Here, a 3D pattern was developed from the initial body, and then enlarged to the target size by the conventional split grading method. Two feminine pants patterns were examined by 3D virtual fitting. We observed that the 3D offset/projection pants pattern was well fitted, having an evenly distributed surplus, as compared with the sample developed using the split grading method. The difference between the two patterns were apparent at the location where several curved lines merged.

• 한국레이저가공학회지
• /
• 제10권1호
• /
• pp.29-34
• /
• 2007

We propose a novel application of laser engraving to patterning of light guide panel (LGP) for backlight. The feasibility of three-dimensional engraved pattern in the LGP was verified by measuring brightness and uniformity. To improve the overall uniformity, we have modified proposed patterns and found improved design for patterns. The tailoring of pattern by using laser engraving method could endow the controllability of uniformity. The proposed LGPs are more efficient in both average brightness and uniformity of illumination than the conventional LGPs which have surface pattern on the panel.

• 한국광학회지
• /
• 제12권1호
• /
• pp.17-24
• /
• 2001

엄밀한 결합파 해석(rigorous coupled-wave analysis)을 이용하여 2차원 및 3차원의 주기적인 구조 제작을 위한 2차원 이진위상 회절격자를 설계 및 분석하였다. 이 회절격자는 근접장 홀로그래피를 위한 위상 마스크로서 수직 입사하는 빛에 대하여 여거 개의 회절파들을 발생하고 이들은 공간상에 주기적인 간섭무늬를 형성한다. 입사파의 편광상태, 파장, 표면 양각형태, 요철 깊이와 duty cycle을 바꿈으로써 회절된 빛들을 조절할 수 있는데 2차원 구조의 경우 0차 회절효율이 최소가 되고 1차회절효율이 최대가 될 때 최적의 결과를 보인다. 한편 0차 회절효율이 상당한 크기를 가지거나 심지어 다른 차수의 회절효율보다 높을 때 마이크로 미터 이하의 미세구조를 갖는 tetragonal-body-centered 구조와 hexagonal 구조의 포토닉 결정을 제작 할 수 있는 다양한 형태의 3차원 공간 간섭무늬가 형성된다.

• 한국정보통신학회논문지
• /
• 제4권1호
• /
• pp.59-65
• /
• 2000

This paper describes the characteristics of a one dimensional narrow-wall slotted waveguide array with a single-layer linear-to-circular polarization converter consisting of a dipole array. An external boundary value Problem of one slot and three dipoles, which approximates the mutual coupling between the dipole array and an edge slot extending over three faces of a rectangular waveguide, is formulated and analyzed by the method of moments; design of polarization conversion is conducted for this model as a unit element. If every unit element has perfect circular polarization, grating lobes appear in the array pattern due to the alternating slot angle: these are suppressed in this paper by changing the dipole angle and degrading the axial ratio of the unit element. The validity of the design is confirmed by the measurements. The dipole array has negligible effects upon slot impedance; the polarization conversion for existing narrow-wall slotted arrays is realized by add-on dipole array.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.3440-3445
• /
• 2007

For proton exchange membrane fuel cell, it is very important to design the flow channel on separation plate optimally to maximize the current density at same electrochemical reaction surface and reduce the concentration polarization occurred at high current density. In this paper, three dimensional computation model including anode and cathode domain together was developed to examine effects of flow patterns and operation conditions such as humidity and operating temperature on performance of fuel cell. Results show that voltage at counter flow condition is higher than that at coflow condition in parallel and interdigitated flow pattern. And fuel cell with interdigitated flow pattern which has better mass transport by convection flow through gas diffusion layer has higher performance than with parallel flow pattern but its pressure drop is increased such that the trade off between performance and pressure drop should be considered for selection of flow pattern of fuel cell.

• Nuclear Engineering and Technology
• /
• 제48권1호
• /
• pp.189-199
• /
• 2016

Fast neutrons with a broad energy spectrum, with which it is possible to evaluate nuclear data for various research fields such as medical applications and the development of fusion reactors, can be generated by irradiating proton beams on target materials such as beryllium. To generate short-pulse proton beam, we adopted a deflector and slit system. In a simple deflector with slit system, most of the proton beam is blocked by the slit, especially when the beam pulse width is short. Therefore, the available beam current is very low, which results in low neutron flux. In this study, we proposed beam modulation using a buncher cavity to increase the available beam current. The ideal field pattern for the buncher cavity is sawtooth. To make the field pattern similar to a sawtooth waveform, a multiharmonic buncher was adopted. The design process for the multiharmonic buncher includes a beam dynamics calculation and three-dimensional electromagnetic simulation. In addition to the system design for pulsed proton generation, a test bench with a microwave ion source is under preparation to test the performance of the system. The design study results concerning the pulsed proton beam generation and the test bench preparation with some preliminary test results are presented in this paper.

• 전자공학회논문지
• /
• 제51권1호
• /
• pp.195-201
• /
• 2014

본 연구에서는 $(2D)^2PCA$ 알고리즘을 이용한 pRBFNNs 패턴분류기 기반 얼굴인식 시스템을 설계하였다. 기존의 1차원 PCA는 행과 열의 곱으로 표현한 이미지의 차원을 축소한다. 하지만 $(2D)^2PCA$(2-Directional 2-Dimensional Principal Components Analysis)는 이미지의 행과 열에서 각각 차원축소를 수행한다. 그 다음 제안된 지능형 패턴분류기로 축소된 이미지를 사용하여 성능을 평가한다. (pRBFNNs)로 성능 평가를 한다. 제안된 다항식 기반 RBFNNs은 조건부, 결론부, 추론부 세가지의 기능적 모듈로 구성되어 있고 조건는 퍼지 클러스터링을 사용하여 입력 공간을 분할하고, 결론부는 RBFNNs의 연결가중치로 일차 선형식으로 표현한다. 또한 차분진화 알고리즘을 이용하여 제안된 분류기의 파라미터, 즉 입력의 수, 퍼지 클러스터링의 퍼지화 계수를 최적화 한다. 얼굴인식에 많이 사용되는 Yale과 AT&T를 사용하여 인식률을 평가하였다. 실험 평가를 위해 IC&CI 연구실 데이터를 추가하여 실험하였다.