• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.1
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• pp.36-47
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• 2012

In this study, the control performance of resonator was reviewed through numerical analysis and 3-dimensional hydraulic model experiments by attaching the resonator suggested in the existing studies to the openings of rectangular harbor and breakwater placed in a straight line to reduce short-period waves. In the numerical analysis, linear analysis method of singularity distribution method based on vertical-line Green function and full non-linear analysis method by 3D-NIT model were applied, and the validity of the numerical analysis methods was verified through comparative analysis between results of hydraulic experiments and numerical analysis results. In addition, effectiveness of the resonator was confirmed by reviewing its control performance on the short-period waves through review on the comparison with the case in which the resonator is not attached.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.10
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• pp.925-933
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• 1991

Caracteristics of cylindrical rectanyular patch microshtrip resonator are analyzed by cavity model. To minimize the error of resonant frequency due to fringing field, the resonant frequency is calcylated by the concept of effective dielectric constant. The transmisson type resonator operating at 3GHz is designed and manufactured. The measured data of the resonant frequency and reflection loss are 3.019Ghz and \ulcorner32.78dB respectively. These results nearly coincide with theoretical results.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.434-434
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• 2022

인간과 인간활동은 물환경시스템의 외생변수가 아닌 내생변수(endogenous variable)이기에, 향후의 물환경관리는 인간과 물환경의 공진화(coevolution)에 대한 이해가 필요하다. 인간과 물환경의 공진화는 인간활동에 따른 정책의 변화, 자연재해, 그리고 결과적 현상으로서의 수질 변화 등과 같은 사회시스템과 수문(또는 물환경)시스템의 상호작용으로 발생한다. 수질과 대중의 물환경에 대한 인식 변화는 각각 물환경시스템과 사회시스템의 변화과정을 대변하는 주요 요인 중 하나이다. 따라서 인간과 물환경의 공진화를 이해하기 위하여 수질과 인식 변화에 대한 해석이 선행되어야 한다. 본 연구에서는 수질측정망 자료를 활용하여 한강유역 주요지점에 대한 수질인자(BOD, COD, T-N, T-P 등)의 변화를 분석(1997~2020년)하고, 신문기사를 활용하여 물환경에 대한 대중의 장기적인 인식 변화(1960~2020년)를 해석하였다. 또한, 지난 61년 동안(1960~2020년) 수질과 대중의 인식 변화, 그리고 주요 물환경 정책 변화가 어떤 상호작용을 통해 공진화해 왔는지 검토하였다.

• The Journal of the Acoustical Society of Korea
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• v.16 no.1
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• pp.76-80
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• 1997

Acoustic resonance characteristics were analyzed and their effect on the refrigerating capability were experimentally verified on a fabricated Hofler-type thermoacoustic refrigerating system. Factors governing the overall resonance are the resonator composed of a cavity and two pipes, the loudspeaker driving the resonator, and rear side impedance characteristics of speaker housing. All these are coupled with electric constants of the speaker to exhibit electric resonance. Also the 'wall-effect' within the resonator causes attenuation to reduce the sharpness of the resonance. Analysis and experiments showed housing and the wall-effect of the resonator reduce the sharpness of resonance. Maintaining the accuracy of the resonance is, therefore, very important for efficient refrigeration.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.822-824
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• 2003

본 논문에서는 압전체의 3차원 유한 요소 해석을 통해 압전체의 공진 특성을 해석하였으며 이를 실험적으로 검증하였다. 검증된 유한요소법을 압전 외팔보(Piezoelectric Bimorph cantilever)에 적용하여 임피던스 해석을 수행하였으며 실험 결과와 비교하여 해석의 타당성을 검증하였다. 또한 팬용 압전 외팔보의 공진 특성 해석을 통해 공진 주파수, 변위 및 편향각을 계산하였다. 이를 통해 펀용 압전 외팔보의 적용 가능성을 확인하였다.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.421-422
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• 2012

본 논문은 넓은 범위에서 변화하는 입력 전압과 출력 전류 조건에서 동작하는 공진형 직류-직류 컨버터의 디지털 제어기 해석 및 설계에 대해 기술한다. LLC 직렬 공진형 컨버터의 전력 변환단 동 특성을 기반으로 디지털 제어기를 해석 및 설계하고, DSP 기능을 내장한 16 비트 마이크로 컨트롤러를 이용하여 제어기를 구현한다. 개발된 디지털 제어기를 150W 공진형 컨버터 보드에 적용하여 설계 이론을 실험적으로 검증하고, 종래의 아날로그 제어기를 적용한 컨버터와의 장단점과 동 특성을 비교 검증한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.497-499
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• 2013

In this paper, electrical lengths and impedances of a dual-mode resonator are calculated by using the transfer function of a dual-mode resonator by realizing the short-stub. The electrical length of transmission-line for a resonator is function of the frequency and the electrical length of stub is defined by the frequency and impedances of line and stub. Also, the inverter value of a bandpass filter using the dual-mode resonator is calculated. The effect of stub's impedance for inverter is very small. And, as the impedance of line is decreasing, the inverter value is increasing and as the bandwidth is increasing, the inverter value is increasing.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.7
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• pp.14-21
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• 2001

In this paper, we designed and fabricated C-band bandpass filter using dielectric resonators. From waveguide cutoff frequency which applied the region between adjacent dielectric resonators, the height of cavity is determined. The cavity's diameter is determined to the twice of dielectric resonator? diameter considering the conductor loss. The resonant frequency of the DR cavity is calculated with non decaying mode analysis. Conventionally, cylindrical dielectric resonator is analysed by Cohn's model which use the decaying mode in the region between dielectric resonator wall and circular cavity wall, which is an approximated method. The external quality factor, $Q_{ex}$ has found with simulation result using Ansoft's Maxwell simulation tool. The designed filter using dielectric resonators with dielectric constant of 45 has the passband center at 5.065GHz. The bandpass filter using dielectric resonators has about 1dB insertion loss, 20MHz bandwidth and more than 30dB attenuation at $f_0+15MHz$.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.595-608
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• 2013

This paper is proposed the computation method of moored ship motion considering harbor resonance, and estimated that the harbor resonance have an effect on moored ship motion. The computation of harbor resonance was used CGWAVE model and the computation of moored sip motion was used the Green function method expressed by three dimensions. This method was verified with the field observation data of moored ship motion, and the application of actual harbor was investigated with wave field data and down time record data in Pohang New Harbor. The resonance periods in Pohang New Harbor that obtained from wave field data were 80, 33, 23, 8 minute, which are the long waves, and 42, 54, 60 second, which are the infra-gravity waves inside harbor slip. The simulated results of harbor resonance were corresponded with the wave field data. This study was investigated on 5,000 ton, 10,000 ton and 30,000 ton ship sized in Pier 8 of Pohang New Harbor that the harbor resonance has effect on moored ship motion from simulated results of ship motion in case of included resonance and excluded resonance. In case of included resonance, the ship motion have increased by 12~400 percent when compared with results of excluded resonance. We could find that the harbor resonance have still more an effect on the surge and heave motions of a large size ship and the roll and yaw motions of a small size ship.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.359-363
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• 2000

기존의 직사각형 마이크로스트립 평면구조 패치 안테나를 변형하여 패치상에 오목한 구조를 갖는 새로운 3차원 패치구조의 마이크로스트립 안테나를 제안하고, 그 공진주파수와 대역폭 변화 특성을 연구하였다. 오목형 구조의 크기에 따라 공진 주파수와 대역폭이 증가하는 것으로 관찰되었으며, 복사특성은 기존의 마이크로스트립 안테나와 거의 유사한 특성을 나타내었다. 새로운 3차원 구조를 갖는 패치에 대한 해석 및 설계는 FDTD 방법을 사용하였으며, 이에 대한 검증을 위해 기존의 마이크로스트립 안테나와 제안된 오목형 구조의 안테나를 제작하여 측정한 결과 공진주파수 및 대역폭 특성 변화가 해석결과와 잘 일치함을 확인할 수 있었다.