• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1404-1405
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• 2007

본 연구에서 우리는 ITO 전극을 사용하지 않은 새로운 전극구조를 가지는 PDP를 제안하였다. 제안한 경사형 대향전 극구조는 언덕형태의 유전체층 사이에 경사형 버스전극을 가진 PDP의 방전 특성을 연구하였는데 제안한 구조는 긴 방전 경로, 낮은 방전전류, 높은 휘도와 효율의 특징을 나타내었다. 기존의 면방전형 전극구조와 비교하였을 때 발광 효율은 1.8배 휘도는 약 45% 증가하였으며 방전전류는 약 38% 정도 감소하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.243.2-243.2
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• 2013

본 실험에서 $SiO_2$, $SiN_x$ 게이트 절연막에 따른 ITZO 산화물 반도체 트랜지스터를 제작하여, 온도변화에 따라 전달 특성 변화를 측정하여 열에 대한 소자의 안정성을 비교, 분석하였다. 온도가 증가함에 따라 carrier가 증가하는 온도 의존성을 보이며, 이로 인해 Ioff가 증가하였다. multiple-trapping 모델을 적용하여, 이동도 증가와 문턱 전압이 감소를 확인하였다. 또한 M-N rule을 적용하여 $SiO_2$, $SiN_x$ 게이트 절연막을 가진 ITZO 산화물 박막 트랜지스터의 활성화 에너지를 추출하고, sub-threshold 지역에서 활성화 에너지의 변화량이 $SiO_2$, SiNX 각각 0.37 eV/V, 0.24 eV/V로 차이를 통해 $SiN_x$ 게이트 절연체를 가진 ITZO 산화물 반도체 트랜지스터의 이동도와 문턱 전압의 변화가 더 컸음을 확인하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.37-41
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• 2007

Fast Fourier Transformation(FFT) is one of the most useful way to analyze response signal for the purpose of grasping the dynamic characteristics of system. Excitation is a factor or process making noise or vibration. It's typical and simple experimental method widely used for catching hold of dynamic peculiar characters and modal behaviors of system by frequency analysis. There are harmonic excitation, impact excitation, random excitation, sweep excitation, chirp excitation and so on as the ideal method in an experiment using exciter. In this thesis, excitation testing module for NI-PXI equipment is developed. The analyzing module is developed with LabVIEW tool. A user can generate each waveform for shaking a structure and see quickly and easily modal shape of system with this module. This developed module will be expected to build up more convenient and serviceable measurement system.

• The Journal of the Acoustical Society of Korea
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• v.10 no.1
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• pp.30-36
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• 1991

Since the Complex Young's Modulus of acoustic materials is a function of frequency under a static load, a cylindrical specimen modelled by rod-like one with losses is used to determine the dynamic characteristics of materials. The specimen is excited into longitudinal vibration at its one end by shaker and at the other end, loaded by a mass corresponding to the desired static load and thus the transfer function of specimen is measured. This transfer function method is analyzed theoretically and experimentally over a frequency range of 50 Hz to 20 KHz. The analysis includes the measurability of the transfer function, the frequency range of the method and lateral motion effect.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.1
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• pp.93-101
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• 2000

In a gas-turbine engine, fan blades in flow path are confronted with many kinds of loading. The study of the excited force by the wake of struts has proposed and the possibility of fatigue failure about rotating fan blades by the excited force at the steady state is evaluated. Equations of the excited force of wakes has been derived at the steady state and the maximum pressure distributions measured at the transient state are proposed. Dynamic characteristics and the fatigue strength of fan blades by experimental test were obtained. To evaluate HCF(High Cycle Fatigue) damage of fan blades, FEM analysis was performed with a steady state harmonic response, which was followed by high cycle fatigue damage factor from goodman diagram.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.4
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• pp.271-277
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• 2017

In this paper, the amplitude and frequency dependent dynamic characteristics of the equivalent stiffness of a rubber bushing are investigated. A new mathematical model is proposed to explain the large deformation and size effect of a rubber bushing. The proposed model consists of elastic, viscous, and frictional stress components and the equivalent strain. The proposed model is verified using experimental results. The comparison shows that the proposed model can accurately predict the equivalent stiffness values of a rubber bushing under various magnitudes and frequencies. The developed model could be used to predict the dynamic equivalent stiffness of a rubber bushing in automotive engineering.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.5
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• pp.61-69
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• 2007

The main purpose of this study is to provide a basic information for the seismic capacity evaluation and the seismic design of low-rise reinforced concrete (RC) shear wall buildings, which are comprised of a pilotis in the first story. In this study, relationships between strengths and ductilities of each story of RC buildings with pilotis are investigated based on the nonlinear seismic response analysis. The characteristics of low-rise RC buildings with pilotis are assumed as the double degree of freedom structural systems. In order to simulate these systems, the pilotis is idealized as a degrading trilinear hysteretic model that fails in flexure and the upper story of shear wall system is idealized as a origin-oriented hysteretic model that fails in shear, respectively. Stiffness properties of both models are varied in terms of story shear coefficients and structures are subjected to various ground motion components. By analyzing these systems, interaction curves of required strengths for various levels of ductility factors are finally derived for practical purposes. The result indicates that the required strength levels derived can be used as a basic information for seismic evaluation and design criteria of low-rise reinforced concrete shear wall buildings having pilotis structure.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.5
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• pp.179-186
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• 2010

When a structure is damaged, its dynamic responses (natural frequency, acceleration, strain) are found to be changed. The ANN(Artificial Neural Network) damage-assesment method is that some measured dynamic signals from the structural changing dynamic responses are applied to ANN to assess the structural damage. Although there have been some studies on a certain typical cases so far, it is rare to find studies about the characteristics of the ANN damage-assesment method or about its applicability, its strength and weakness. So this study researches on the characteristics of ANN damage assesment method and on a problem in application of the various dynamic responses to ANN. What the ANN damage assessment method usually does in past researches is to teach an ANN by using some response signals obtained from damaged structures under one kind of excitations and to identify the locations and the extents of damage of same structures under the same excitations. However, the excitations inflicted on the structures are not always the same. Thus this study experiments whether a ANN which is trained using the same excitations is able to identify the damage when different excitations inflict. All response signals are obtained from experimental models.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.906-907
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• 2011

본 논문은 3D 타원형 결함을 가진 알루미늄 판에 대하여 와전류 탐상 프로브 중 Impedance, T/R, T/T 프로브를 설계하여 결함에서의 특성을 파악하였다. 특성 파악을 위해 세 가지의 결함에 대하여 프로브 코일 임피던스의 실수, 허수 변화에 따른 와전류 센서의 특성을 비교하였다.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.351-353
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• 1998

본 논문에서는 보다 효율적인 영상 처리를 위해 생물 시각 시스템의 특성을 반영하는 영상 표현 방법을 제안한다. 기존의 방법들이 단순화된 특성들만을 이용한 것인데 비해 본 논문에서 제안하는 방법은 고등 생물의 시각이 독립된 처리 경로를 가진 다는 점에 기반을 두고 있으며, 각 처리 경로의 시작이 되는 두 가지의 신경절 세포가 가지는 수용장의 분포 및 크기의 특성을 독립적으로 고려하여 각각 인식 및 움직임 정보 처리에 효율적인 영상 표현을 얻어낸다. 제안된 방법에 대한 실험 및 분석을 통하여 본 방법이 영상의 데이터를 효율적으로 축약시켜줄 수 있음을 알 수 있다.