• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.173-175
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• 1999

This paper deals with the rotor vibration analysis of Switched Reluctance Motor(SRM) with the 6/4 poles. For this analysis, 3-dimensional mode shapes corresponding to the natural frequency and critical speed map according to rotor speed are presented by using 3D Transfer Matrix Method(TMM). The gyroscopic effect and shear deformation of rotor are considered.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.363-365
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• 1999

800kV GIS(Gas Insulated Switchgear) was first developed by Hyosung Corporation in Korea at Dec. 1998 and is going to be installed first in the Dangjin Thermal Plant. We intoned to verify the structural safety of 800kV GIS under seismic load. The modal analysis of 800kV GIS has been carried out to obtain the natural frequency and mode shape. PATRAN was used for mode)ing exactly 800kV GIS Geometry. 800kV GIS FE(Finite Element) model was constructed of shell elements for the enclosures and beam elements for the conductors and the support insulators NASTRAN was used for analyzing the normal modes of 800kV GIS FE model.

• 대한조선학회논문집
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• 제40권2호
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• pp.28-33
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• 2003

This study is performed to evaluate and design the dynamic characteristics of the onboard machinery with resilient mounts. To avoid resonance with onboard machinery and external force, it is necessary to calculate natural frequencies of the resilient mounting system more accurately. Natural frequencies of on board machinery are determined by rigid body properties(mass, moment of inertia, center of mass) of machinery and stiffness of mounts. But it is very difficult to calculate rigid body properties theoretically. And stiffness properties of rubber mounts vary with dynamic displacement, pre load, frequency and temperature, and so on. In this study, we have identified rigid body properties using experimental modal analysis and estimated dynamic stiffness of rubber mount for onboard machinery using measured vibration response during seatrial. We measured displacement excitation through deck under mounts and evaluated relationship between modes of resilient mounting system and main excitation sources of a ship.

• 산업기술연구
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• 제27권B호
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• pp.129-135
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• 2007

In this paper, an modal analysis based on the distribution of the electromagnetic fields on the UWB elliptical patch-slot antenna is presented. We designed the UWB antenna by iterating the dimensional parameters of the antenna as the traditional design method. Then the antenna was carefully analyzed using 3D E-M simulator. The result of the analysis shows that the slot antenna operates on a series of the multi-pole radiations based on TE modes matched to the system impedance. This result gives us an easier method to design the similar antennas, which is the impedance matching to the system impedance after once constructing a proper structure with a series of multi-mode resonances.

• International Journal of Advanced Culture Technology
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• 제8권2호
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• pp.159-164
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• 2020

The response analysis of frame structure with open section beams considering warping conditions and short duration load have been performed. When a beam of frame structure is subjected under torsional moment, the cross section will deform a warping as well as twist. For some thin-walled sections warping will be large, and accompanying warping restraint will induce axial and shear stresses and reduce the twist of beam which stiffens the beam in torsion. Because of impact or blast loads, the wave propagation effects become increasingly important as load duration decreases. This paper presents that a warping restraint in finite element model effects the behavior of beam deformation, dynamic mode shape and response analysis. The computer modelling of frame is discussed in linear beam element model and linear thin shell element model, also presents a correlation between computer predicted and actual experimental results for static deflection, natural frequencies and mode shapes of frame. A method to estimate the number of normal modes that are important is discussed.

• International Journal of Naval Architecture and Ocean Engineering
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• 제1권2호
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• pp.101-107
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• 2009

The VIV (Vortex-Induced Vibration) analysis of a flexible cylindrical structure under locally strong shear flow is presented. The model is made of Teflon and has 9.5m length, 0.0127m diameter, and 0.001m wall thickness. 11 2-dimensional accelerometers are installed along the model. The experiment has been conducted at the ocean engineering basin in the University of Tokyo in which uniform current can be generated. The model is installed at about 30 degree of slope and submerged by almost overall length. Local shear flow is made by superposing uniform current and accelerated flow generated by an impeller. The results of frequency and modal analysis are presented.

• 한국철도학회논문집
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• 제7권3호
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• pp.259-263
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• 2004

The running safety of a railway vehicle depends on the design parameters and contact condition between wheel and rail. In this study, the effect of the conicity of wheel tread is analyzed using ADAMS/RAIL software on running situation. Modal analysis shows in 0.6 Hz natural frequency of lateral mode in fully arranged the KTX cars. The excessive vibration of the tail cars occurs in the 17th car as the speed and the stiffness of the secondary suspension increases, and especially for 1/40 conicity of the GV40 wheel. Also, the analysis shows that combination of wheel profile, GV40 for power cars and XP55 for passenger cars can reduce the lateral vibration of the tail cars.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.1282-1288
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• 2006

Upon demands for the requests of rapid, safe and comfort transit, the proven high speed bogie having not only high-quality but also good running performance is required by customer all over the railway vehicle for narrow gauge. Hereupon, the running test on roller testing rig for developed semi-high speed bogie for narrow gauge was carried out in order to verify the running performance and safety. The aim of the test is to assess the dynamic behaviour of the bogie on straight track including the running stability, ride quality, modal frequency and dynamic response.

• 한국정밀공학회지
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• 제20권6호
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• pp.197-204
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• 2003

This paper presents an efficient modeling and dynamic analysis method for open cracked beam structures. An equivalent bending spring model is introduced to represent the structural weakening effect in the presence of cracks. The proposed method adopts the exact dynamic element method (EDEM) to avoid the inconvenience and numerical errors in association with re-meshing the structural model with the crack position changed. The proposed modeling method is validated through a series of simulation and experiments. First, the proposed method is rigorously compared with a commercial finite element code. Then, two kinds of experiments are performed to validate the proposed modeling method. Finally, a diagnostic scheme fur open cracked beam structures is proposed and demonstrated through a numerical example.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2002년도 추계학술발표논문집 (상)
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• pp.707-710
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• 2002

본 논문은 오디오와 비디오 정보의 융합을 통한 멀티 모달 음성 인식 시스템을 제안한다. 음성 특징 정보와 영상 정보 특징의 융합을 통하여 잡음이 많은 환경에서 효율적으로 사람의 음성을 인식하는 시스템을 제안한다. 음성 특징 정보는 멜 필터 캡스트럼 계수(Mel Frequency Cepstrum Coefficients: MFCC)를 사용하며, 영상 특징 정보는 주성분 분석을 통해 얻어진 특징 벡터를 사용한다. 또한, 영상 정보 자체의 인식률 향상을 위해 피부 색깔 모델과 얼굴의 형태 정보를 이용하여 얼굴 영역을 찾은 후 강력한 입술 영역 추출 방법을 통해 입술 영역을 검출한다. 음성-영상 융합은 변형된 시간 지연 신경 회로망을 사용하여 초기 융합을 통해 이루어진다. 실험을 통해 음성과 영상의 정보 융합이 음성 정보만을 사용한 것 보다 대략 5%-20%의 성능 향상을 보여주고 있다.