• 전자공학회논문지A
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• 제32A권6호
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• pp.787-798
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• 1995

We implement the E-plane T-juncition manifold mutiplexer having low insertion loss for output multiplexer of Ku-band satellite transponder. Manifold multiplexer implemented here is composed of 2 channel filters, T-junctions, half-wave waveguide connecting channel filters and manifold, and manifold itself.[1-4] Considering the mass and volume of the satellite transponder, the channel filters are designed to dual-mode.[5-13] And Elliptic filter function is used, which has good characteristics of suppressing the interference between 2 channels. Since the performance of manifold multiplexer depends on the manifold waveguide transmission line length, it's necessary proper analysis. In this paper, we do optimization process of T-junction and other elements by using CAD and implement the manifold multiplexer. An experiment shows that characteristic response of multiplexer matches wel its modeling result.

• Journal of Advanced Marine Engineering and Technology
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• 제23권6호
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• pp.748-754
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• 1999

The acoustic performance of reactive type single expansion chamber can be calculated theoretically by plane wave theory. But higher order modes should be considered to widen the frequency range. Munjal has suggested the method for analyzing the acoustic properties of simple expansion chamber with taking into consideration of higher order mode of inlet/outlet. But his method cannot predict the acoustic properties exactly when the dimensions of inlet/outlet and expansion chamber have not integer multiples. In this paper the new method was suggested to overcome the shortcomings of Munjal's method The predictions by this method were also compared with those by the finite element method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.324.1-324
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• 2002

The continuous Gabor wavelet transform (GWT) has been utilized as a useful time-frequency analysis tool to identify the rapidly-varying characteristics of some wave signals. In the application of GWT, it is important to select the Gabor wavelet with the optimal shape factor by which the time-frequency distribution of a signal can be accurately estimated. To find the signal-dependent optimal Gator wavelet shape factor, the notion of the Shannon entropy which measures the extent of signal energy concentration in the time-frequency plane is employed. (omitted)

• 한국음향학회:학술대회논문집
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• 한국음향학회 1999년도 학술발표대회 논문집 제18권 1호
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• pp.297-302
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• 1999

평판의 일반적인 형태의 진동을 해석하기 위해서는, 외면진동뿐만이 아니라 내면진동을 해석하여야 한다. 평판 내면진동의 경우 탄성파인 종파와 전단파의 전파에 의한 영향으로 발생하며, 진동 변위, 진동 에너지, 진동 인텐시티 등의 특성들을 이해하기 위해서는 각 파동의 영향을 분리하여 낼 필요가 있다. 내면진동을 해석하기 위하여 진동 모드법을 사용할 수 있으나, 각 파동에 의한 영향을 분리하여 낼 수가 없다. 본 논문에서는 진동장을 탄성파들에 의한 영향의 합으로 나타냄으로써, 각 파동에 의한 진동 변위, 진동 에너지, 진동 인텐시티 둥의 영향들을 분리할 수 있는 해석 방법을 제안하고자 한다. 이러한 해석 방법을 이용하여 점가진력에 의하여 강제 진동하는 평판의 내면 진동장에 대한 수치 계산을 수행하였다. 결과로써 진동 변위, 진동 에너지, 진동 인텐시티 등을 이루는 탄성파들의 기여도와 특성들을 분석함으로써 본 해석기법의 유용성을 보였다.

• 전자공학회논문지A
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• 제32A권12호
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• pp.25-35
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• 1995

An analysis method of electromagnetic coupling through an arbitrarily shaped aperture on the upper wall of parallel-plate waveguide, when excited by an electromagnetic plane wave from outside, is considered. The mixed-potential integral equation, in which Green's functions are expressed in a computationally efficient closed form by using the Prony's method and the Sommerfeld identity, is formulated. Expanding the unknown equivalent magnetic surface current in terms of two-dimensional rooftop-type basis functions and choosing razor testing, the integral equation is reduced to a linear algebraic equation, which is solved. The results are compared with the previous results. Fairly good agreements between them are observed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.649-652
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• 1997

The method for the calaulation of the input impedanc of cavity with water is proposed in this paper the electric field and input impedance are calaulated for the water with high conductivity to verify this method. And the electric field and RCS (radar cross section) is calculated when the plane wave scattered by high permitivity and low conductivity material. The calculated results are compared with exact solution. Then this method is compared with the conventional method.

• 센서학회지
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• 제7권1호
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• pp.9-16
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• 1998

본 논문에서는 구형의 수중 구조체에 평면 음향파가 입사될 경우에 발생하는 산란파 음압의 크기와 방향성이 3차원적으로 어떻게 분포되는 지 살펴보고 자 한다. 이를 위한 수치해석적 방법으로 결합형 유한요소-경계요소(FE-BE) 기법을 개발하였다. 이 같은 구형 모델의 수치해석적 결과를 기존의 이론적 해답과 비교하여 본 연구에서 개발한 결합형 FE-BE 기법의 타당성을 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.402-405
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• 1988

With dichromated bleacher and alcohol drying, over effi. of 81% has been achieved for holographic gratings. It is recorded by two plane waves at 632.8 nm in Agfa 8E75 film. Swollen emulsion and rapid dehydration make a strong modulation. The model works well close to the Bragg condition. It is suggested modified parameters of coupled-wave theory which have good agreement with experimental results.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권10호
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• pp.481-486
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• 2003

It is well known that a discharge in oil is the source of various physical phenomena. Ultrasonic-wave detection is a useful method to the diagnosis of the transformer-insulation condition. Conventionally, ultrasonic waves are detected by Piezo-electric transducer, and we use optical method that has many advantages. In this paper, we constructed a Mach-Zehnder interferometer with optical fiber and investigated the principle of operation. Test arrangement is based on the needle-plane electrode system in oil and applied AC high voltage. Ultrasonic waves were detected and analyzed with wavelet transform.

• 한국산업정보학회논문지
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• 제8권2호
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• pp.1-6
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• 2003

접지된 유전체 슬랩 위에 주기적으로 스트립 격자가 놓여 있는 주기구조에서 TE 편파된 평면파에 대한 전자파 산란현상을 이론적으로 해석하였다. 제시된 구조를 이론적으로 해석하여 수치 해석한 결과인 유체층의 두께 변화에 대한 반사파 전력과 모드별 계수, 입사각의 변화에 대한 반사파 전력 및 스트립상에 유기되는 전류 등을 제시하였다. 그리고 제시된 구조에서 관찰되는 Bragg blazing 현상에 관해서 상세히 기술하였다.