• 한국음향학회지
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• 제18권7호
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• pp.75-79
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• 1999

다중채널 탄성파 음원배열에서 불발 음원에 따라 탐사 성능에 미치는 영향을 확인하기 위하여 음원배열의 빔 패턴과 원거리장 파형 변화를 비교 분석하였다. 원거리장 파형의 주신호 진폭은 전체 건 부피의 약 40%에 해당하는 음원들이 불발을 일으킬 경우, 탐사성능이 66% 정도 유지되는 것으로 확인되었다. 154㎐에서 같은 간격의 음원들이 불발 시에는 배열 형태와 관계없이 길이 및 폭 배열의 빔 폭이 동일하게 나타난다. 길이 배열의 빔 패턴에서는 불발된 음원의 부피가 증가됨에 따라 빔 폭이 41°에서 34°로 좁아지는 경향을 나타낸다. 따라서 부피가 작은 음원 배열일수록 빔폭이 좁고 양호한 파형이 생성되므로 작은 에너지가 요구되는 천부 지층탐사에 적합한 것으로 확인되었다.

• 한국위성정보통신학회논문지
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• 제10권4호
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• pp.46-51
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• 2015

본 논문에서는 항재밍 GPS(Global Positioning System) 시스템을 위한 선형 어레이 안테나(linear array antenna) 시뮬레이터(simulator)를 설계하고 시뮬레이션을 통해 다양한 성능 평가를 수행하였다. 먼저 GPS 위성의 신호 구조 분석을 통해 모의 송신신호를 발생시키고, 선형 어레이 안테나 고려시 잡음 환경하에서의 어레이 수에 따른 SNR(Signal to Noise power Ratio) 성능을 분석하였다. 또한 MMSE(Minimum Mean Square Error) 방식의 신호처리 시스템을 통해 재머(jammer) 수에 따른 항재밍 빔패턴(beam pattern) 성능을 분석하였으며, 안테나 칼리브레이션(calibration) 문제를 고려하여 어레이간 지연이 존재하는 경우에서의 항재밍 성능을 분석하였다.

• 한국소음진동공학회논문집
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• 제19권9호
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• pp.922-927
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• 2009

The transducers used in active sonar on surface ships are packed in a specific geometry in the array drum in order to meet the requirements such as the source level, directional beam pattern, etc. This paper describes the acoustic characteristics of the cylindrical array which is based on a 64 vertical staves arrangement, each stave composed 5 independent transducers. Firstly, the single transducer on the rigid baffle in the water is analyzed with the Finite Element Method. From the result of the FE analysis nodal velocities on the radiation surface is calculated and used with the boundary conditions of the transducers mounted on the array drum. Then the acoustic pressure is calculated in the field points using the Boundary Element Method and the other acoustic informations, the source level, beam pattern, near field and far-field distance, were acquired.

• 전자공학회논문지A
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• 제28A권1호
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• pp.23-29
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• 1991

In order to improve the radiation characteristics of the microstrip antenna, microstrip array antenna consisting of one center patch fed by a coaxial probe and several patches directly coupled to the E-plane by microstrip line is analyzed. The equivalent circuit of the array antenna is represented by the conventional transmission line and the various parameters, such as the mdicrostrip line length, the patch length and the feed point location are calculated to improve the radiation pattern for 5-patch array antenna which has the equal patch width. The 5-patch array antenna with the radiation pattern which has low sidelobe level and narrow beam width is fabricated and then the measured results are compared with the computed values and the results of the single patch microstrip antenna too.

• 전기전자학회논문지
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• 제24권3호
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• pp.917-920
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• 2020

본 논문에서는 Ku대역 통신시스템을 사용하는 큐브 위성에 장착이 가능한 평면배열안테나 있어, isoflux 방사특성을 유도하기위한 급전신호 가중치 분석에 관하여 연구하였다. 평면배열안테나는 큐브위성 장착성을 고려하여 8*8개의 방사소자를 평면 배열하였으며, 각 축 기준 방사소자 간 간격은 0.5 lambda로 설정하였다. isoflux 방사특성 유도를 위한 급전신호 가중치는 저대역 통과필터 설계에 활용되는 신호처리 기법을 이용하여 산출하는 방법을 제시하였다. 본 논문에서 제안된 방법의 분석 결과 원활한 isoflux 패턴을 유도할 수 있음을 확인하였다.

• Tribology and Lubricants
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• 제27권5호
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• pp.264-268
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• 2011

In this study, we examined the friction characteristics of a dimple pattern on a carbon nitride coating. The study was conducted with a hexagonal array 40 ${\mu}m$ dimple pattern on a steel bearing containing a CNx coating. The area density of the dimple patterns were varied between 5% and 25%, the speed was varied from 0.06-0.26 m/s, and the load was varied between 20-100N. In general, we found that as the velocity increased, the friction coefficient increased. Furthermore, the friction coefficient was lowest at a load of 40N. The friction coefficient of the non-coated specimen was 0.025-0.15; on the other hand, the friction coefficient of the coated specimen was 0.002-0.02. Thus, we determined that the coated materials could reduce the friction coefficient by a factor of 7.5.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.367-370
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• 2005

In this paper, we made a Singly Fed patch which is the fittest at the feeding part. And we found out return loss and radiation pattern about dielectric rod array antenna which has six's passive element to shape FTEP(Flat-topped element pattern) after we analyzed the characters of singly dielectric rod antenna. We show the conclusion that has the optimum return loss and more flat radiation pattern.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.357-360
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• 2005

In the synthesis of the continuously distributed line source antennas with arbitrary patterns, the formulas of Taylor sum pattern and Bayliss difference pattern have been mainly used. In this paper, an optimization scheme is newly presented to directly synthesize the desired difference patterns from Taylor line source formula, and then the distributions are numerically adapted to the specified difference patterns by using an appropriate iterative sampling method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1526-1531
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• 2007

Data transmission capacity that is required in 2010 is forecasted that increase by optical communication capacity more than present centuple, and is doing increased demand of optical communication related industry product present. Specially, Lid glass' application that is one of optical communication parts is used in optical communication parts manufacture of Fiber array, Ferrule array, Fanout Black, Silica optical waveguide chip and splitter etc. Also, it is used widely for communication network system, CATV, ATM-PON, FTTH and system. But, Lid glass need much processing times and becomes cause in rising prices of optical communication parts because production cost is expensive. The objectives, of this work is to suggest the micro concave and convex pattern manufacturing technology on borosilicate plate using high temperature and compression molding method. As a result, could developed micro pattern Mold more than 5 pattern, and reduce Lid Glass manufacture cycle time.

• 대한전자공학회논문지
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• 제26권12호
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• pp.1956-1964
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• 1989

In this paper, a new method of Hangul recognition is proposed to solve the problems of misrecognition owing to the contacts of FCEs (Fundamental Character Elements) in a Hangul pattern. Structures of FCFs are represented with PAG(Programmed Array Grammar) to recognize an input pattern on 2-D. array of pels., and the unnecessary deformation of the conventional approach can be eliminated by using PEACE parsing which extracts primitives and computes attributes in the course of analyzing the structure of an input pattern. Also, primitive transformation at contacts can afford to confirm all the possible structures of an input pattern and solve the problem of misrecognition owing to the contacts of FCEs. The recognition rate of proposed method for printed Hangul characters shows 96.2% for 1978 Gothic-letters and 92.0% for 1920 Myng-style-letters, respectively.