• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 학술대회 논문집 전문대학교육위원
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• pp.52-55
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• 2000

In this paper, the coupled and the non-coupled vibration mode AE sensor for GIS were simulated by finite element analysis and manufactured, and characterized. The maximum sensitivity was 64.3 dB when the resonant frequency of the coupled vibration mode AE sensor was 166 kHz and the maximum sensitivity was 58.9 dB when the resonant frequency of the non-coupled mode AE sensor was 265 kHz. The coupled vibration mode AE sensor responded higher than the non-coupled vibration mode AE sensor at the partial discharge detection in GIS.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.94-94
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• 2000

In this paper, the performance of INS/GPS integration is analyzed. Generally the integration method is classified into two method. One is loosely coupled integration, Another is tightly coupled integration. For the simulation, the error model of Kalman fitter is defined and the result of simulation is analyzed. When the number of visible satellites is less than four, the error of tightly coupled integration is smaller than that of loosely coupled integration. To very the result of simulation, van test that use LP-81 IMU and Millen3151R GPS receiver is carried out.

• Wind and Structures
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• 제1권2호
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• pp.175-181
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• 1998

Torsional flutter occurs at 2D rectangular cylinders with side ratios B/D smaller than about 8 or 10. On the other hand, slender cylinders indicate the occurrence of coupled flutter, which means the coupled derivatives of slender cylinders have more significant role for flutter instability than that of bluffer ones. In this paper, based upon so called "Step-by-step analysis", it is clarified the coupled derivatives stabilize torsional flutter instability of bluffer cylinders (e.x. B/D=5), while they destabilize torsional flutter or coupled flutter instabilities of mores slender cylinders. The boundary of them exists between B/D=5 and 8.

• Journal of Power Electronics
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• 제17권3호
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• pp.621-631
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• 2017

A KY converter integrated with a conventional synchronously rectified (SR) boost converter and a coupled inductor is presented in this paper. This improved KY converter has the following advantages: 1) the two converters use common switches; 2) the voltage gain of the KY converter can be improved due to the integration of a boost converter and a coupled inductor; 3) the leakage inductance of the coupled inductor is utilized to achieve zero voltage switching (ZVS); 4) the current stress on the charge pump capacitors and the decreasing rate of the diode current can be limited due to the use of the coupled inductor; and 5) the output current is non-pulsating. Moreover, the active switches are driven by using one half-bridge gate driver. Thus, no isolated driver is needed. Finally, the operating principle and analysis of the proposed converter are given to verify the effectiveness of the proposed converter.

• Nonlinear Functional Analysis and Applications
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• 제29권2호
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• pp.559-580
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• 2024

In this paper, we aim to prove coupled and common coupled fixed point theorems for contractive type conditions in the context of partial metric spaces by means of a control function, and to provide some corollaries of the established results. This paper presents a number of results that generalize and extend previous work in the field. In order to better illustrate the process, we provide examples.

• 한국항공우주학회지
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• 제36권12호
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• pp.1139-1145
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• 2008

로터 블레이드의 구조변형을 포함한, 제자리 비행하는 로터 블레이드의 공력해석을 수행하였다. 와류포획능력을 향상시킨 전산유체 코드와 간단한 오일러-베르누이 보 모델에 기반을 둔 구조역학 방정식을 결합시켜 회전익 유동에 대한 연계 계산을 수행하였으며 계산결과 타당한 로터블레이드 구조변형 및 공력특성을 얻었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.318-321
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• 2005

In vibro-acoustic analysis, the commercial CAE tools, such as SYSNOISE, is usually used to take into account of the coupled effects of fluid acoustics and structural vibration. The acoustic field can be solved by either FEM or BEM, while the vibration field is usually solved by FEM. The interior or exterior acoustic problems with the coupled effects of the structural boundary could be solved by the commercial tools. The commercial tools, however, could not solve the problems in case that both the interior and exterior acoustic field is coupled with the structural boundary. In this paper, a realistic method based on FEM/BEM coupling scheme is presented to analyze the acoustic radiation from the internal source in a chamber to external acoustic field through elastic structural boundary. Several numerical examples are implemented to validate the developed program.

• Computers and Concrete
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• 제20권3호
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• pp.257-262
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• 2017

This study aims to develop a signal processing scheme to accurately predict the thickness of concrete slab using air-coupled impact-echo. Air-coupled impact-echo has been applied to concrete non-destructive tests (NDT); however, it is often difficult to obtain thickness mode frequency due to noise components. Furthermore, apparent velocity in concrete is a usually unknown parameter in the field and the thickness of the concrete slab often cannot be accurately measured. This study proposes a signal processing scheme using guided wave analysis, wherein dispersion curves are drawn in both frequency-wave number (f-k) and phase velocity-frequency ($V_{cp}-f$) domains. The theoretical and experimental results demonstrate that thickness mode frequency and apparent velocity in concrete are clearly obtained from the f-k and $V_{cp}-f$ domains, respectively. The proposed method has great potential with regard to the application of air-coupled impact-echo in the field.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.752-755
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• 2001

In order to investigate the vibration characteristics of fluid-structure interaction problem, we modeled two rectangular identical plates coupled with bounded fluid. The fixed boundary condition along the plate edges and an ideal fluid are assumed. MSC/NASTRAN was used to perform finite element analysis and analytic solutions were compared with experimental solutions to verify finite element model. As a result, comparison of FEM and experiment show good agreement, and the transverse vibration modes, in-phase and out of-phase, were observed alternately in the fluid-coupled system. The effect of distance between two rectangular plates on the fluid-coupled natural frequency is investigated.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.851-856
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• 2003

This paper proposes a single-mode Lamb-wave generation and detection system using a pulsed laser as a generator and an air-coupled transducer combined with the wavelet transform analysis, as the detector. The laser source with arrayed linear slits was used to generate Lamb-wave which is able to control the wavelength of Lamb-wave to be generated by changing the slits separation. An ari-coupled transducer was used to receive Lamb-wave, which can selectably receive a single mode of leaky Lamb wave by changing the oblique angle of transducer, since the leaky Lamb-wave has unique leaky-angle according to the mode. Also, the received signal was processed by wavelet transform for the analysis in domain of time-frequency. The theoretical dipersion curve and the experimetal result was compared to show good agreement.