• 한국추진공학회지
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• 제21권2호
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• pp.9-17
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• 2017

비정상 충격파 유도연소의 주기적 압력 진동 특성을 연구하기 위하여 DMD 방법을 적용하였다. Lehr의 충격파 유도 연소 실험을 기반으로 수치적인 연구를 수행하였다. Lehr의 실험을 4 수준의 격자를 이용하여 수치적으로 모사하였으며, FFT 결과로부터 430-435 kHz의 주파수가 계산되었다. 실험 결과는 약 425 kHz로 해석 결과와 유사한 것을 확인하였다. FFT 해석에서 도출되지 않은 저주파 특성을 파악하기 위해 dynamic mode decomposition (DMD) 방법을 적용하였다. 여러 가지 모드 주파수가 계산되었고, 연소불안정 평가 인자 중 하나인 damping coefficient를 도출하여 안정/불안정성을 평가하였다.

• Journal of Power Electronics
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• 제9권6호
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• pp.884-891
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• 2009

An address voltage stabilization circuit for the single-side driving (SSD) method for AC plasma display panels (PDP) is proposed. The single-side driving method, which eliminates a common sustaining driver, uses only two electrodes in a three electrode AC PDP structure. The high-impedance (Hi-Z) mode operation of the data drive ICs during the sustaining period is needed for surface gas-discharge without misfiring in the SSD method but it produces the problem that the address voltage increases up to the breakdown voltage. The proposed circuit based on a flyback converter can stabilize the address voltage under the breakdown voltage and provide better surface gas-discharge performance without any misfiring in the SSD scheme.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.78-81
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• 2002

This paper describes on the design structure and development temperature stable strip-line junction isolator operating in above resonance mode. Temperature characteristics of isolator depend on magnet, YIG(Yttium Iron Garnet) ferrite, and conductor etc. These require temperature stability and possible methods of compensation for the temperature dependent effects. In this paper, the analysis and measurement of the temperature characteristics were carried out for the material isolator prototype. The bandwidth of isolator was expended and the center frequency shift was reduced in temperature range of -20∼8O$^{\circ}C$.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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• pp.390-392
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• 2009

This paper is concerned with the stabilization problem of nonlinear networked control systems with time-delay via Takagi-Sugeno(T-S) fuzzy control approach. The T-S fuzzy models are employed to represent nonlinear systems with Markovian jump parameters and time-delay. The purpose of this paper is to design a fuzzy controller such that the closed-loop Markovian jump fuzzy system is stochastically stable. Based on a stocastic Lyapunov function, stabilization sufficient conditions using a mode-independent fuzzy controller are derived for the Markovian jump fuzzy system in terms of Linear Matrix Inequalities(LMIs). Finally, a simulation example is presented to illustrate the effectiveness of the proposed method.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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• pp.329-331
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• 2009

This paper is concerned with the stabilization problem of nonlinear networked control systems with time-delay via Takagi-Sugeno(T-S) fuzzy control approach. The T-S fuzzy models are employed to represent nonlinear systems with Markovian jump parameters and time-delay. The purpose of this paper is to design a fuzzy controller such that the closed-loop Markovian jump fuzzy system is stochastically stable. Based on a stocastic Lyapunov function, stabilization sufficient conditions using a mode-independent fuzzy controller are derived for the Markovian jump fuzzy system in terms of Linear Matrix Inequalities(LMIs). Finally, a simulation example is presented to illustrate the effectiveness of the proposed method.

• 대한기계학회논문집A
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• 제25권4호
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• pp.602-609
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• 2001

This paper is concerned with the orthotropic problem of diaphragm-type air springs which consist of rubber linings, nylon reinforced rubber composite and bead ring. The analysis is carried out with a finite element method developed to consider the orthotropic properties, geometric nonlinearity using four-node degenerated shell element with reduced integration. Physical stabilization scheme is used to control the zeroenergy mode of the element. The analysis includes an inflation analysis and a lateral analysis of an air spring for the deformed shape and the spring load with respect to the vertical and l ateral deflection. Numerical results demonstrate the variation of the outer diameter, the fold height, the vertical force and the lateral force with respect to the inflation pressure and the lateral deflection.

• 한국전기전자재료학회논문지
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• 제15권12호
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• pp.1075-1078
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• 2002

This paper describes on the design structure and development of temperature stable strip-line function isolator operating In above resonance mode. Temperature characteristics of isolator depend on magnet, YIG(Yttium Iron Garnet) ferrite, and conductor etc. These require temperature stability and possible methods of compensation for the temperature dependent effects. In this paper, the analysis and measurement of the temperature characteristics were carried out for the material isolator prototype. The bandwidth of isolator was expended and the frequency shift at center was reduced in the temperature range of -20∼80$\^{C}$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2624-2626
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• 2000

The stabilization controls of coupled tank system and ball-beam system are difficult control tasks because of their high order time delay, nonlinearity and structural unstability. Fuhermore, a series of classical methods such as a conventional PID and a full state feedback controller(FSFC) based on the local linearizations have narrow stabilizable regions. Therefore, in this paper, in order to stabilize two representative nonlinear system mentioned above, a Sliding Mode Controller based on a Real Variable Elitist Genetic Algorithm(RVEGA SMC) was proposed.

• 한국정밀공학회지
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• 제30권3호
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• pp.331-339
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• 2013

The Interest in disease prevention and rehabilitation is increasing depending on increase of patients with spinal. This is being developed using the spine stabilization device is being studied. So far studies have only evaluated the effect on trunk stabilization exercises but analysis of human movement patterns for active movement and passive movement did not. We assessed the muscle activity of trunk and leg muscle during passive and active tilt mode on eight tilt directions at tilt angle of $30^{\circ}$ using 3-D dynamic postural balance training system. We performed experimental study on the muscular activities of trunk muscle about rectus abdominis, external obliques, latissimus dorsi, erector spinae, and leg muscle about rectus femoris, Biceps femoris, Tibialis Anterior, gastrocnemius. As a result, muscle activation was different depending on the direction of movement and pattern. The results indicate that various patterns of spinal stabilization exercise system could be applied to an effective training of chronic low back pain patients.

• 제어로봇시스템학회논문지
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• 제21권2호
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• pp.145-149
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• 2015

This paper introduces a sway suppression control for container cranes with unknown payloads and sway rates. With no priori knowledge concerning the magnitude of payload mass and sway rate, the proposed control maintains superior sway suppressing and trolley positioning against external disturbances. The proposed scheme combines a second order sliding mode control and an adaptive control to cope with unknown payloads. A second order sliding mode control without feedback of the sway rate is first designed, which is based on a class of feedback linearization methods for stabilization of the under-actuated sway dynamics of the container. Under applicable restrictions of the magnitude of payload inertia and sway rate, a linear regression model is obtained, and an adaptive control with a payload estimator is then designed, which is based on Lyapunov stability methods for the fast attenuation of trolley oscillations in the vicinity of the target position. The asymptotic stability of the overall closed-loop system is assured irrespective of variations of rope length. Simulation are shown in the existence of initial sway and external wind disturbances.