• 한국정보통신학회논문지
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• 제6권4호
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• pp.589-594
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• 2002

Hairpin 형태의 필터는 크기를 작게 설계할 수 있지만 설계방법이 복잡하다는 단절이 있다. 본 논문에서는 기존의 전송선로 이론과 J 인버터 회로를 이용하여 Hairpin Line 필터 설계에 새롭게 적용하였으며, 설계하는데 필요한 J 와 b 파라미터를 정확히 구하는 방법을 제시하고 있다. 인접하는 소자간의 상호 결합이 없는 부분을 고려하였으며, 각 단에서의 결합성분에 대한 전기적인 결합선로 길이를 J 와 b 파라미터로부터 구할 수 있다. 제시하고 있는 설계방법으로 Serenade 8.0을 이용하여 중심 주파수 2.6GHz에서 동작하는 소형의 Hairpin Line 대역 통과 필터를 설계하고 컴퓨터 시뮬레이션을 통하여 특성을 확인하였다.

• 한국항해항만학회지
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• 제36권9호
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• pp.737-740
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• 2012

A miniaturized CMOS bandpass filter for a single RF transceiver system is presented, using diagonally end-shorted coupled lines and lumped capacitors. In contrast to conventional miniaturized coupled line filters, it is proven that the effective permittivity variation of the coupled transmission line has no effect on shifting the center frequency when the bandpass filter is highly miniaturized. A bandpass filter at a center frequency of 2 GHz was fabricated by $0.18{\mu}m$ CMOS technology. The insertion loss with the die area of $1500{\mu}m{\times}1000{\mu}m$ is -5.14 dB. Simulated results are well agreed with the easurements. It also verify the center frequency stability in the compact size bandpass filter.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.411-413
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• 2013

휴대폰, 컴퓨터, 멀티미디어 등의 보급으로 인하여 영상 신호처리는 여러 영역에서 응용되고 있다. 그러나 영상은 대부분 임펄스 잡음에 의해 훼손되며, 화질개선을 위한 잡음제거 기술의 필요성이 대두되고 있다. 잡음제거를 위한 기존의 방법에는 평균 필터, 메디안 필터 등이 있지만, 미흡한 잡음제거 특성을 나타낸다. 따라서 본 논문에서는 임펄스 잡음제거를 위해 표준편차를 이용한 변형된 평균 필터 알고리즘을 제안하였으며,시뮬레이션 결과,제안한 방법은기존의 방법들에 비해우수한 잡음제거 특성을나타내었다.

• 한국항해학회지
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• 제22권4호
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• pp.59-67
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• 1998

A quick and automatic detection with no harm to the goods is very important task for improving quality control, process control and labour reduction. In real fields of industry, defect detection is mostly accomplished by skillful workers. A narrow band eliminating spatial filter having characteristics of removing the specified spatial frequency is developed by the author, and it is proved that the filter has an excellent ability for on-line and real time detection of surface defect. By the way,. this spatial filter shows a ripple phenominum in filtering characteristics. So, it is necessary to remove the ripple component for the improvement of filter gain, moreover efficiency of defect detection. The spatial filtering method has a remarkable feature which means that it is able to set up weighting function for its own sake, and which can to obtain the best signal relating to the purpose of the measurement. Hence, having an eye on such feature, theoretical analysis is carried out at first for optimal design of narrow band eliminating spatial filter, and secondly, on the basis of above results spatial filter is manufactured, and finally advanced effectiveness of spatial filter is evaluated experimentally.

• 한국지반공학회논문집
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• 제24권11호
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• pp.121-131
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• 2008

슬러리월 연직차수벽 시공시, 지반을 트렌치 형태로 굴착하고, 굴착시공 중 굴착면 붕괴에 대한 안정성을 유지하기 위하여 벤토나이트와 물을 혼합한 슬러리를 트렌치에 채운다. 이렇게 채워진 벤토나이트 슬러리로 인하여 필터케이크(filter cake)이라 불리는 얇고 투수성이 낮은 층이 트렌치벽 표면에 형성되며, 슬러리가 제거 된 이후에도 굴착면에 잔존하여 연직차수벽에서의 순간변위시험(slug test) 해석 결과에 중요한 영향을 미친다. 본 연구에서는 기존에 개발된 수치해석 프로그램 Slug-3D를 수정하여 순간변위시험 해석시 필터케이크의 영향을 고려하는 방법을 제시하고 이를 통하여 정확한 연직차수벽의 투수계수를 산출하도록 하였다. 필터케이크의 영향을 고려하기 위하여 Slug-3D에서는 차수벽과 토양층의 경계면에 불투수조건(no-flux)을 경계조건으로 설정하여 해석을 수행하였다 또한 투수계수 산정에서 기존의 타입커브법(type curve method)을 이용하기 위하여 개선된 type curve를 도출하였고, 선형 커브피팅법(line-fitting method)를 필터케이크가 존재하는 연직차수벽에 적용할 수 있도록 수정 보완하였다. 본 논문에서 제안된 필터케이크를 고려한 해석방법은 EMCON(1995)에 의해 수행된 현장시험 결과의 재해석을 통하여 타당성을 검토하였다. 또한, 본 연구에서 얻어진 결과를 Choi and Daniel(2006)에 의해 수행된 필터케이크가 존재하지 않는 경우의 순간변위시험 해석결과와 비교를 통해 필터케이크 고려가 반드시 필요함을 보여준다.

• 한국초전도ㆍ저온공학회논문지
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• 제6권4호
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• pp.46-50
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• 2004

The Experimental results of the in-line type inertance tube pulse tube cryocooler for cooling superconductor RF filter are presented in this paper. The pulse tube refrigerator, which has no moving parts at its cold section, is attractive in obtaining higher reliability, simpler construction, and lower vibration than any other small refrigerators. The purpose of this study is to analyze the characteristics of in-line type inertance tube pulse tube refrigerator (IPTR), and to get main factor to improve the performance of the in-line type IPTR. Firstly, design parameters of the in-line IPTR are discussed by ARCOPTR program, and then to find optimal conditions of in-line type IPTR, cool down characteristics according to the variations of the charging pressure, inertance tube volume, regenerator volume and pulse tube volume are measured by the experiment. The lowest temperature of the cold end was about 50 K. Cooling capacity was the highest in the charging pressure of 32 atm. and 5W at 72K. On the other hand, COP of the in-line type IPTR was the highest in the charging pressure of 21 atm. and 0.018 at 77K.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.34-37
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• 2007

액체산소를 작동유체로 하여 추진제 공급배관에 대한 충진 및 대기 시험을 수행하였다. 추진제 공급 시스템은 추진제 탱크의 출구에 필터가 장착된 형상이다. 추진제의 충진이 완료된 후 대기 과정동안 액체산소의 증발과 이것이 시스템의 재순환 성능에 미치는 영향을 살펴보았다. 추진제의 충진 속도와 탱크 얼리지의 압력이 배관 내 액체산소의 상태에 영향을 미치는 것을 확인하였다. 필터의 장착 위치로 인해 대기 과정동안 배관 내부에서 geysering 현상은 발생하지 않았다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.1039-1042
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• 1995

In real time application such as motion control, it is hard to find the application of non-causal filtering due to its need for future position data, even though it shows wide usage in off-line digital signal processing. Recently, some of motion control areas such as learning and repetitive control use non-causal filtering technique in their application. these kinds of zero-lag non-causal filter application are very usful not only to reduce the machine vibration, but also to increase control accuracy with comparatively less work. In this paper, genuine method to implement zero-lag non-causal filter in a CNC is introduced. Also the variation of this implementation for the learning operation is suggested to give the NC better control performance for a specific job. By adopting the new NC architecture call Soft-NC, all these implementions are made possible here, and especially large memory requirement which hinders their usage for many years is no longer barrier in their real world application.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권11호
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• pp.3145-3162
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• 2023

As an important technology of the internetwork, wireless sensor network technique plays an important role in indoor localization. Non-line-of-sight (NLOS) problem has a large effect on indoor location accuracy. A location algorithm based on improved particle filter and directional probabilistic data association (IPF-DPDA) for WSN is proposed to solve NLOS issue in this paper. Firstly, the improved particle filter is proposed to reduce error of measuring distance. Then the hypothesis test is used to detect whether measurements are in LOS situations or NLOS situations for N different groups. When there are measurements in the validation gate, the corresponding association probabilities are applied to weight retained position estimate to gain final location estimation. We have improved the traditional data association and added directional information on the original basis. If the validation gate has no measured value, we make use of the Kalman prediction value to renew. Finally, simulation and experimental results show that compared with existing methods, the IPF-DPDA performance better.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 추계학술대회 학술발표 논문집
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• pp.527-531
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• 1998

This study introduce to the fuzzy membership filter to cancel a high frequency noise of welding current. And ART2 which has the competitive learning network classifiers the signal patterns for the filtered welding signal. A welding current possesses a specific pattern according to the existence or the size of a welding gap. These specific patterns result in different classification in comparison with an occasion for no welding gap. The patterns In each case of 1mm, 2mm, 3mm, and no welding gap are identified by the artificial neural network. These procedure is an off-line execution. In on-line execution, the identification model of neural network for the classified pattern is located on ahead of the welding plant. And when the welding current patterns pass through the neural network in the direction of feedforward. it is possible to recognize the existence or the size of a welding gap.