• 전자공학회논문지 IE
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• 제47권3호
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• pp.47-52
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• 2010

본 논문에서 P-HEMT를 이용한 100 mW급 중전력 주파수체배기를 제안한다. 3차 고조파 성분을 발생 시키는 비선형 장치를 이용하여 2.4GHz의 입력을 3체배 하여 7.2GHz 주파수를 얻도록 설계하였다. 주파수 체배기는 로드풀 모의실험 방식을 이용하여 설게 하였고 기본파와 2차 고조파가 억압된 노치 필터를 사용 하였다. 15dBm 입력에 약21dBm의 출력을 얻도록 하였다 즉 6dB의 변환 이득을 얻었고 기본파에서 20dBc 2차 고조파에서 30dBc의 고조파 억압을 하였다.

• 산업공학
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• 제12권3호
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• pp.480-486
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• 1999

Mold base design is one of the most critical steps in production of plastic parts. This paper presents an efficient method for generating a 3D CAD library for injection mold base and mold components. In this paper, a new description language (DL)formats are proposed. These DL formats can represent the geometric feature, the variable dimensions and the assembly structures of mold base and its components. And the processes of adding the mold components and creating the mold assemblies can be performed very easily and efficiently by using DL scripts. Proposed method has been tested by implementation of 3D library with DL scripts and DL-interpreter with C language. The DL and interpreter are independent of CAD system. They were applied to the automatic mold base designing system which works on Unigraphics V15. The system is developed with UG API function under Windows-NT environment.

• Wind and Structures
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• 제11권5호
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• pp.361-376
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• 2008

This paper considers internal pressure fluctuations for a range of building volumes and dominant wall opening areas. The study recognizes that the air flow in and out of the dominant opening in the envelope generates Helmholtz resonance, which can amplify the internal pressure fluctuations compared to the external pressure, at the opening. Numerical methods were used to estimate fluctuating standard deviation and peak (i.e. design) internal pressures from full-scale measured external pressures. The ratios of standard deviation and peak internal pressures to the external pressures at a dominant windward wall opening of area, AW are presented in terms of the non-dimensional opening size to volume parameter, $S^*=(a_s/\bar{U}_h)^2(A_W^{3/2}/V_{Ie})$ where $a_s$ is the speed of sound, $\bar{U}_h$ is the mean wind speed at the top of the building and $V_{Ie}$ is the effective internal volume. The standard deviation of internal pressure exceeds the external pressures at the opening, for $S^*$ greater than about 0.75, showing increasing amplification with increasing $S^*$. The peak internal pressure can be expected to exceed the peak external pressure at the opening by 10% to 50%, for $S^*$ greater than about 5. A dominant leeward wall opening also produces similar fluctuating internal pressure characteristics.

• 전자공학회논문지 IE
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• 제46권1호
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• pp.37-43
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• 2009

본 논문에서는 구면 좌표계 기반에서 3차원 모델을 검색하는 새로운 알고리즘을 제안한다. 3차원 모델 위의 임의의 점들의 좌표(x, y, z)를 구하고, 이 좌표들을 구면좌표계의 좌표로 변환한다. 이 샘플들의 위도(zenith)의 분포를 3차원 모델의 특징으로 정의한다. 임의의 샘플 좌표를 구하기 위해 우리는 Osada가 제안한 방법을 사용하였고, 좌표축을 정규화하기 위하여 PCA 알고리즘을 사용하였다. 데이터는 프린스턴 대학의 벤치마크 데이터를 사용하였으며 Vranic이 제안한 depth buffer-based feature vector 알고리즘과 비교하였고, 본 논문에서 제안한 방법이 정확도에서 12.6% 더 정확하게 모델을 검색하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.883-884
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• 2004

High-speed IC for time-division multiplexing (TDM) optical transmission systems have been designed and fabricated by using InP heterojunction-bipolar-transistor (HBT) technology. The driver IC was developed for driving external modulators, featuring differential outputs and the operation speed up to 10 Gbps with an output voltage swing of 1.3 Vpp at each output which was the limit of the measurement. Because -3 dB frequency was 20GHz, this circuit will be operated up to 20Gbps. 1.3Vpp differential output was achieved by switching 50 mA into a 50 $\Omega$ load. The power dissipation of the driver IC was 1W using a single supply voltage of -3.5Y. Input md output return loss of the IC were better than 10 dB and 15 dB, respectively, from DC to 20GHz. The chip size of fabricated IC was $1.7{\Box}1.2 mm^{2}$.

• 산업공학
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• 제9권2호
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• pp.119-128
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• 1996

A procedure is presented for a 3D-contour machining without cutter interferences. The 3D-contouring machining along a spatial curve is often required for manufacturing trimming and flange dies in motor industries. Input data for the machining contour is a spline curve with polynomial vector equation provided by CATIA system. Points are sampled on the contour curve and line segments and helical curves are approximated from the point data. Cutter interference is checked on the approximated spline and all of interference curves are substituted with interference-free helical curves for a tool path generation. The non-machined curve areas are locally machined by tools with smaller diameters. A tool radius offset is considered for generating NC data to be free with tool size.

• 산업공학
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• 제18권1호
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• pp.82-87
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• 2005

Most of virtual reality systems ask users to control 3D objects or to navigate 3D world using 3D controllers. To maximize the human performance in the control, the design of virtual reality system and its input and output devices should be optimized. In this study, an experiment was designed to investigate the effects of three resolution factors of a virtual reality system on the human performance. Six subjects conducted the experiment for the factors; two frame rates, three spatial resolutions, and three pictorial contents. The result showed that the greater the spatial resolution was, the higher the human performance was. For the temporal resolution, fixed frame rate at 18 Hz was better than the varied maximized frame rate. For the pictorial contents, the virtual space with orientation cues marked the greatest performance than the other two conditions; the virtual space without any orientation cue and the virtual space like real world. These results could be applied for the design of virtual reality systems.

• 산업공학
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• 제20권3호
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• pp.376-386
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• 2007

The analytic hierarchy process (AHP), a well-known and useful decision making method, has been applied to R&D project evaluation and selection. The objective of this study is to propose a new model for evaluating and selecting R&D projects of Samsung Electro-Mechanics, the top manufacturer of electronic components in Korea, using the AHP. To show the validity of the new model, we strived to successively compare the final priorities for R&D projects with the priorities obtained by the existing model and the new model respectively.

• 전자공학회논문지 IE
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• 제44권1호
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• pp.10-14
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• 2007

InP의 전자와 정공의 이온화계수로부터 추출한 유효이온화계수를 이용하여 InP 다이오드의 항복전압을 위한 해석적 표현식을 유도하였다. 해석적 항복전압 결과를 $N_D=6\times10^{14}cm^{-3}\sim3\times10^{17}cm^{-3}$의 도핑 농도에서 수치적 결과 및 실험 결과와 비교하였다. 각 농도에 따른 해석적 항복전압은 수치 해석적 결과와 매우 잘 일치하였고, 실험 결과와는 10% 이내의 오차로 잘 일치하였다.

• 산업공학
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• 제25권3호
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• pp.309-318
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• 2012

Forecasting probability or likelihood of technology development success has been a crucial factor for critical decisions in technology management such as R&D project selection and go or no-go decision of new product development (NPD) projects. This paper proposes an analytic network process (ANP) approach to forecasting of technology development success. Reviewing literature on factors affecting technology development success has constructed the ANP model composed of four criteria clusters : R&D characteristics, R&D competency, technological characteristics, and technological environment. An alternative cluster comprised of two elements, success and failure is also included in the model. The working of the proposed approach is provided with the help of a case study example of MRAM (magnetic random access memory) technology.