• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.1051-1054
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• 2005

On this study, we optimized minimizing the characteristic function for mixed result of the structural contact analysis and the buckling analysis according to the pin jig initial model's level change using mixed the table of orthogonal away and ANOM, Pin jig's weight is reduced up to 20 percent considering constraint conditions. Also we optimized reducing 20 percent weight of pin jig model using topology optimization.

• 설비공학논문집
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• 제9권3호
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• pp.259-267
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• 1997

Average heat transfer coefficients and friction coefficients have been measured from staggered short pin-fin arrays to investigate the effect of fin shapes. Flow entering into the test section is a fully developed duct flow and the Reynolds number ranges from 5,000 to 25,000 based on fin diameter and average approaching velocity. The fin has three different shapes; uniform-diameter circular fin, two stepped-diameter circular fins. Average heat transfer rates change slightly with the fin shapes. However, friction loss(pressure loss) for the stepped-diameter fins is significantly less than that for the uniform-diameter fin. This results indicate that the stepped-diameter fin arrays in duct flow enhance heat transfer rates largely based on unit pumping power.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1950-1953
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• 1996

A $1\;{\times}\;4$ micro mirror array is designed and fabricated. In contrast to other micro mirrors which utilize torsional flexure hinges or cantilevers for restoring torque and supporting purpose, we have placed a substrate hinge structure under each mirror. Each micro mirror consists of address electrode, substrate hinge consisting of pin and staple, supporter post, and mirror plate. Electrical connection between mirror plate and ground electrode is established by substrate hinge. Mirror undergoes a rotational motion due to electrostatic force when voltage difference is applied between address electrode and mirror plate. Micro mirrors with two different types of staple shape and two different pin sizes are designed and fabricated. Each mirror is designed to have ${\pm}\;10^{\circ}$ of deflection angle and have $100\;{\times}\;110\;{\mu}m^2$ of size.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.164-169
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• 2005

Microphone array techniques are being used widely in wind tunnel measurements for identification of the distributed aerodynamic noise sources on the model being tested. Depending on the frequencies and sound levels, conventional beamforming algorithm has limitation in separating two adjacent sources. Several modifications to the classical beamforming have been developed to enhance way resolution and reduce sidelobe levels. In this Paper the robust adaptive beamforming and the CLEAN algorithm are used to compare to the result of conventional beamforming method. It is found that the CLEAN algorithm is capable of pin-pointing locations of multiple sources nearby, while these sources are unidentifiable with robust adaptive or conventional beamforming techniques.

• Tribology and Lubricants
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• 제24권6호
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• pp.368-373
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• 2008

This paper will investigate the friction characteristics of a 100m Hexagonal Array, Micro-scale Dimple Pattern, on bearing steel. These characteristics are researched by utilizing a pin-on-disk wear test machine, under various test conditions. The reduction of friction is a necessary requirement for the improved efficiency of this machine. As the speed increases, there is a decrease in the effect of the dimple of friction characteristic, with substantially little change to density. Conversely, as the load increases, the dimple pattern grows larger, resulting in a difference in the texture of these two components. At a dimple density of 10% the friction characteristic is easily demonstrated, with a consistent change in both speed and load.

• ETRI Journal
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• 제41권6호
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• pp.715-730
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• 2019

We propose a switched beam-forming antenna that satisfies not only ultra-wideband characteristics but also beam-forming in the WLAN frequency band using an ultra-wideband antenna and passive parasitic elements applying a broadband optimal reactance load algorithm. We design a power and phase estimation function and an error correction function by re-analyzing and normalizing all the components of the parasitic array using control system engineering. The proposed antenna is compared with an antenna with a pin diode and reactance load value, respectively. The pin diode is located between the passive parasitic elements and ground plane. An antenna beam can be formed in eight directions according to the pin diode ON (reflector)/OFF (director) state. The antenna with a reactance load value achieves a better VSWR and gain than the antenna with a pin diode. We confirm that a beam is formed in eight directions owing to the RF switch operation, and the measured peak gain is 7 dBi at 2.45 GHz and 10 dBi at 5.8 GHz.

• 전자공학회논문지SC
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• 제39권5호
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• pp.34-42
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• 2002

본 논문에서는 움직임 추정을 위한 블럭정합 알고리즘의 고속 처리를 위한 VLSI 어레이의 구조를 설계하였다. 완전탐색 블럭정합 알고리즘의 데이터 의존관계로부터 일차원 시스톨릭 어레이를 유도했다. 제안된 일차원 시스톨릭 어레이에 입력된 데이터와 제어신호는 인접한 처리요소를 통해서 전달되어 재사용된다. 따라서 제안된 시스톨릭 어레이는 시간 및 공간적 지역성을 만족한다. 데이터와 제어신호의 입출력 핀은 일차원 어레이의 시작과 끝의 처리요소에만 존재한다. 이 구조는 입력포트의 수가 적으며, 모듈러 확장성을 갖는다. 기준블럭과 최대탐색거리가 확장된 경우에 제안된 어레이를 연결하여 움직임 추정기를 구성할 수 있다.

• 한국정밀공학회지
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• 제24권5호
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• pp.82-88
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• 2007

This work is to fabricate a precise optical fiber array using polymer composite for optical interconnection. Optical fiber array has to satisfy low optical loss requirement less than 0.4 dB according to temperature change. For this purpose, design criteria for an optical fiber array was derived. The coefficient of thermal expansion of silica particulate epoxy composites was affected by volume fraction of silica particles. And also, elastic modulus of silica particulate epoxy composites was affected by volume fraction of silica particles. To obtain the coefficients of thermal expansion below $10{\times}10E-6/^{\circ}C$ and elastic modulus more than 20 GPa , we chose the volume fraction more than 76%. Using silica particulate epoxy composites with the volume fraction 76%, 8-channel optical fiber array with dimensional tolerances below $1\;{\mu}m$ was manufactured by transfer molding technique using dies with the uniquely-designed core pin and precisely-machined zirconia ceramic V block. These optical fiber arrays showed optical loss variations within 0.4 dB under thermal cycling test and high temperature test.

• Journal of Radiation Protection and Research
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• 제29권4호
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• pp.257-261
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• 2004

핀홀 감마카메라의 민감도를 향상시키기 위하여 픽셀화된 CsI(Tl) 섬광체와 위치민감형 광증배관을 이용하여 부호화 구경 감마카메라를 개발하였다. Rounded-hole로 이루어진 $13{\times}11$ 픽셀구조의 개조된 uniformly reductant array (URA) 가 계측기의 공간해상도를 고려하여 부호화된 마스크로 선택되었다. 부호화된 구경 카메라와 핀홀 카메라의 성능을 비교하기 위하여 Tc-99m 소스의 여러 가지 형태를 이용하여 테스트 하였으며, 신호 대 잡음비 또는 민감도의 향상에 대한 카메라의 성능을 분석하였다. 그 결과 공간해 상도에 있어서 약간의 저하가 있었으나 영상의 질은 매우 향상되었다. 비록 카메라의 개발과 테스트가 저에너지 영역에서 이루어졌지만, 부호화 구경 카메라의 구상은 방사성 물질 감시 그리고 다른 응용들에 있어서도 효과적으로 사용되어질 수 있을 것이다.

• 한국통신학회논문지
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• 제21권3호
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• pp.763-770
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• 1996

In this paper, the Single-stage Transmission type Injectiong-Locked Oscillator(STILO) was designed and fabicated for the Active Integrated Phased Array Antenna(AIPAA) system. The STILO, which was designed and fabricated by injection-locked technique and hair-pin resonator, has the same 210MHz frequency tuning range of the Voltage Controlled Oscillator(VCO) used by varactor. The locking bandwidth of STILO with 11.5MHz bandwidth, is much better than that of the Injection-Locked Dielectric Resonator Oscillator(ILDRO), And the STILO has the improved noise characteristics in AM, FM, and PM. This STILO is useful for the AIPAA, the coupled VCO array, an the MMIC structure.