• 한국산업융합학회 논문집
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• 제23권6_1호
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• pp.907-915
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• 2020

Specification selection, Layout, specifications and combinations of Power Drives, and Ship motions were studied for FGPP(Floating Gas-fired Power Plants), which are still needed in areas such as the Caribbean, Latin America, and Southeast Asia where electricity is not sufficiently supplied. From this study, the optimal equipment layout in ships was derived. In addition, the difference between engine and turbine was verified through LCOE(Levelized Cost of Energy) comparison according to the type and combination of Power Drives. Analysis of Hs(Significant Height of wave) and Tp(spectrum Peak Period of wave) for places where this FGPP will be tested or applied enables design according to wave characteristics in Brazil and Indonesia. Normalized Sloshing Pressures of FGPP and LNG Carrier are verified using a sloshing analysis program, which is CFD(Computational Fluid Dynamics) software developed by ABS(American Bureau of Shipping). Power Transmission System is studied with Double bus with one Circuit Breaker Topology. A nd the CFD analysis allowed us to calculate linear roll damping coefficients for more accurate full load conditions and ballast conditions. Through RAO(Response Amplitude Operator) analysis, we secured data that could minimize the movement of ships according to the direction of waves and ship placement by identifying the characteristics of large movements in the beam sea conditions. The FGPP has been granted an AIP(Approval in Principle) from a classification society, the ABS.

• 한국항해항만학회지
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• 제37권3호
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• pp.283-289
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• 2013

Wave profiles coming with oblique angle to trapezoidal submerged breakwater on the porous seabed are computed numerically by using a boundary element method. The analysis method is based on the wave pressure function with the continuity in the analytical region including fluid and structure. When compared with the existing results on the oblique incident wave, the results of this study show good agreement. The fluctuation of wave profiles is increased in the rear of the submerged breakwater due to the increase of the transmission coefficient, as the incident angle increases. In addition, in the case of the wave profiles passing over the submerged breakwater on porous seabed, it is able to verify that the attenuation of wave height occurs more significantly due to the wave energy dissipation than that of passing over the submerged breakwater on the impermeable seabed. The results indicate that wave profile own high dependability regarding the change of oblique incident waves and porous seabed. Therefore, the results of this study are estimated to be applied as an accurate numerical analysis referring to oblique incident waves and porous seabed in real sea environment.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.229-232
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• 2005

More than effectively judging the existence of voids behind concrete tunnel linings or under concrete pavements, this research aims to develop the analysis algorithm of radar capable of estimation of the shape of specific voids. To detect or estimate void shapes in non-reinforced concrete, the simulation analysis model of transmission and reflection wave of electromagnetic radar is used. This radar simulation model is carried out with various void shapes. As the results, a proposed method in this study has a possibility of detecting or estimating void shapes with good accuracy.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.352.2-352
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• 2002

In this paper, Power Flow Analysis (PFA) method has been applied to the prediction of vibration energy density and intensity of coupled shell structures in the medium-to-high frequency ranges. To consider the wave transformation at joint between shell elements, power transmission and reflection coefficients are investigated for various joint angles, and here Donnell-Mushtari thin shell theory has been used. (omitted)

• Journal of Advanced Marine Engineering and Technology
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• 제33권5호
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• pp.653-661
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• 2009

In order to reduce the noise and oscillation, it is consider a matter in all aspects about the noise stem from accumulator and the characteristic of transmission, Transformation of outside shape has change of noise occurrence at transmission process. Therefore, performed sound numerical analysis and conducted an experiment to examine the birthplace of accumulator's external shape change. In a sound numerical analysis, we can fond out transmission loss between inlet and outlet's sound pressure. In an experiment, we can make out transmission loss by sound wave separation theory through drawing sound pressure inlet and outlet.

• 한국정보통신학회논문지
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• 제24권3호
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• pp.412-419
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• 2020

군 지휘통신용 네트워크 구조에서 전략제대 통신 기반체계는 발전 방향, 전략 제대 및 회선의 특성과 생존성을 고려할 때 다양한 통신방식의 이원화된 망 구조를 요구한다. 무선방식에서는 MicroWave가 대표적인데 기존의 기술만으로 운용하고 있어 비효율적이라는 지적이 제기되고 있다. 따라서, MW전송시스템 구조 및 효율화 방안과 이에 대한 효과 분석이 필요하다. 기존 전략제대 MW전송시스템에서는 고정된 형태의 접속 구조로 무선 환경을 고려한 효율적인 전송이 어렵다. 적응 변조로 개선이 가능하지만 기존의 접속 구조와 고정된 대역폭으로는 한계가 있다. 이전 연구에서의 가용도와 링크 거리를 고려한 전송 성능 향상 기법에 이어 본 논문에서는 적응 변조 기반 가변 전송 웨이브폼, 대역폭, 거리 변수를 고려하여 개선된 패킷화된 MW전송시스템 구조와 가변 대역폭 전송에 대해 제시하고 가용도와 가변 대역폭 전송 성능 효과에 대해 전략 제대와 지휘 통제 회선을 고려하여 분석을 수행하였다.

• 한국전자파학회지:전자파기술
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• 제1권1호
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• pp.20-27
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• 1990

본연구의 목적은특성엄피던스가서로다른션로가상호접속되어 있을때,외부전자파에 의해 전송선 로에 유기되는 전류를 해석하기 위한 효과적인 방법을 제안하는 데 었다. 이것은 전송선로 해석을 위해 비동차 미분방정식을 상태변수법으로 풀이하는 과정에서 얻어지는 천이행렬의 특성을 이용한 것으로 전송선로모델의 1차측과2차측을상호 변환시킬 수 있는새로운 전환기법이다. 이 방법을 이용하여 완전 도체명연 위의 전송선로모텔에 대한 유기전력의 특성을 시율레이션 결과를 통해 평가하였다.

• The Journal of the Acoustical Society of Korea
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• 제16권1E호
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• pp.49-56
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• 1997

Ultrasonic cleaning at high frequency around 1 MHz, called megasonic cleaning, is commonly used to remove particles less than 1 ㎛ by generating high frequency accelerations on the cleaning objects. Cleaning is performed in an ultrasonically-excited liquid contained in a double-structured container. Ultrasonic waves generated by piezoelectric transducers propagate in the outer container and are transmitted through the inner container. The bottom of the inner container is inclined to make oblique incidence of the ultrasonic wave in order to raise the efficiency of the transmission through the bottom plate. This work deals with the efficiency of the transmission, which directly affects the cleaning performance. The transmission characteristics of the ultrasonic wave in the megasonic cleaner have been obtained analytically and numerically for the variations of some parameters, such as the thickness and inclined angle of the bottom plate of the inner container and the chemical ratio and temperature of the cleaning liquid. The calculated results have yielded the optimum cleaning condition in terms of the sound power transmitted into the cleaning liquid.

• 한국통신학회논문지
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• 제15권3호
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• pp.232-242
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• 1990

외부 평면파에 의해 유기되는 단일 전송선로의 EMI(Electromagnetic Interference) 전류에 관한 Smith의 해석법을 이용하여 연쇄 접속된 전송선로의 부하 EMI전류를 구한다. 동일한 특성 임피던스를 갖는 선로가 연쇄 접속 되었다는 가정하에 수치계산을 하여 Smith의 연구 결과와 비교한 결과 두 결과가 잘 일치함을 확인하였으며, 선로의 폭과 길이가 각각 1/10로 줄어들면 부하 EMI 전류는 약 40dB 정도 감소함을 알 수 있었다.

• 소음진동
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• 제9권3호
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• pp.517-524
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• 1999

Mathematical formulas for multi-dimensional isolation analysis via vibrational power transmission can be derived in a rather simple form when the wave effects of the isolators are completely neglected. With increase of frequency range of interest, however, the wave effects play a very important role and hence cannot be neglected. The formulas get involved accordingly. In this study, a method of equivalent stiffness modeling of the isolators to include the wave effects is proposed in such a way that not only the complexity of the mathematical expressions but also that of experiments of necessity can be reduced. This method is illustratively applied to a two-dimensional vibration isolation system with nonrigid source and base structures.