• Proceedings of the KIEE Conference
• /
• 1995.07b
• /
• pp.685-688
• /
• 1995

In this paper we proposed new scheme replacing adaptive mechanism part in MRAC by fuzzy logic in order to improve transient response in adaptive control system. Conventional adaptive control system has good performance in steady state but it has large error or problem with rise time in transient state. We need to increase adaptation gain of control variable but it causes robustness problem that makes ststem unstable for set-point, load-variation, and dynamic change. To demonstrate presented FTAC(fuzzy tunning adaptive control)'s superiority, presented method is introduced for a class of SISO systems and compare with MRAC. By analyzing simulation result, we can see transient response is improved and the system is not affected by disturbance in proposed method in comparison to MRAC.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.9 no.2
• /
• pp.57-62
• /
• 1997

Based on the facts that significant parts of the harbor response spectrum usually reside in the vicinity of the Helmholtz mode in the eastern part of Korea. economically feasible redemption measures of seiches for malfunctioned harbors already in service is proposed by extending the wisdom of perforated breakwaters and adjusting the width of entrance channel as a control tool. It turns out that as the entrance channel is getting narrower, the harbor system is getting slender due to the increase of added hydrodynamic length so that harbor response can be effectively diminished and separated from the incident wave spectrum where considerable amount of wave energy is located at the lower frequency range.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.7 no.4
• /
• pp.42-50
• /
• 1993

This paper was proposed drive strategy Induction Motor using the fuzzy algorithm of auto-tuning PID control. In fuzzy control, the 1M driving system is controlled in trial and error without the mathematical modeling and using fuzzy lookup table the real time control is possible. Also, ,dividing the fuzzy rules in several zone, the stability and response of the 1M driving system is improved. The parameters of 1M are varying according to the environmental conditions, the variance of the parameters is affected with the driving characteristics of 1M. Using the fuzzy algorithm of the driving system which has the auto tuning control function for high performance, high accuracy of the driving system, a designed and proposed through the comparision with the PID control method and the driving characteristics is reviewed and analyzed.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1453-1455
• /
• 2005

This paper presents self tuning PI controller of IPMSM drive using neural network. Self tuning PI controller is developed to minimize overshoot, rise time and settling time following sudden parameter changes such as speed, load torque and inertia. Also, this paper is proposed speed control of IPMSM using neural network and estimation of speed using artificial neural network(ANN) controller. The results on a speed controller of IPMSM are presented to show the effectiveness of the proposed gain tuner. And this controller is better than the fixed gains one in terms of robustness, even under great variations of operating conditions and load disturbance.

• Journal of Biomedical Engineering Research
• /
• v.14 no.2
• /
• pp.125-136
• /
• 1993

The study of Cochlear biomechanics is to clearly define three biomechanical principles of the Cochlea : Activity, Nonlinearity and Feedback. In this article, the Cochlea is linearly and actively modelled in one dimensional time domain. The sharp tunning of the Basilar Membrane displacement is shown when the amplifying activity of hair cells is added to the model. The amplified energy of the travelling displacement wave is emitted throughout the Cochlear fluid, so that the model becomes unstable. A new technique is introduced to reduce strong echos fro the Helicotrema. It makes the model less unstable. Both pure and click tones are used as input stimuli onto the ear durm. When the model is normal, the click response of the model shows that the backward emission of the amplified fluid pressure has mainly the echos from the Helicotrema. However, when the linear and active model is assumed to be abnormal, that is, some of hair cells are damaged not to produce the active process, the effect of the hair cell damage is resulted in the Oto-acoustic emission. The frequency response of the abnormally emitted sound pressure shows that the Oto-acoustic emission has the information about the characteristic frequency of the damaged hair cell. The main aim of this paper is to demonstrate the active biomechanics of the Chchlea in the time domain.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2023.11a
• /
• pp.1014-1015
• /
• 2023

많은 장애아 부모들은 양육에 대한 스트레스, 미래에 대한 걱정으로 심리적으로 상당한 중압감을 느낀다. 이에 비해 매년 증가하는 장애인 수에 비해 장애아 부모 및 가족의 심리적·정신적 문제를 해결하기 위한 프로그램이 부족하다.[1] 이를 해결하고자 본 논문에서는 감정분석 소통 플랫폼을 제안한다. 제안하는 플랫폼은 KoBERT 모델을 fine-tunning 하여 사용자의 일기 속 감정을 분석하여 장애아를 둔 부모 및 가족 간의 소통을 돕는다. 성능평가는 제안하는 플랫폼의 주요 기능인 KoBERT 기반 감정분석의 성능을 확인하기위해 텍스트 분류 모델로 널리 사용되고 있는 LSTM, Bi-LSTM, GRU 모델 별 성능지표들과 비교 분석한다. 성능 평가결과 KoBERT 의 정확도가 다른 분류군의 정확도보다 평균 31.4% 높은 성능을 보였고, 이 외의 지표에서도 비교적 높은 성능을 기록했다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.6
• /
• pp.671-678
• /
• 2014

This paper presents a Ka-band FMCW sensor that has high linearity by improving a nonlinear behavior of the voltage controlled oscillator. Due to the nonlinear characteristics of the voltage controlled oscillator for the conventional method, the drift of beat frequency can cause inaccuracy and errors to the extracted results. A Ka-band FMCW signal with fast transition time could be generated by using both direct digital synthesizer and phase locked loop in this research. The implemented FMCW sensor showed very high accuracy in beat frequency through the test.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.23 no.1
• /
• pp.124-131
• /
• 2019

A design study of gas turbine engine simulation duct was conducted to investigate the operating characteristics and control gain tunning of the Altitude Engine Test Facility(AETF). The simulation duct design involved testing variable spike nozzle and ISO standard choking nozzle to verify the measurements such as mass flow rate and thrust. The simulation duct air flow area was designed to satisfy Ma 0.4 at the aerodynamic interface plane(AIP) at engine design condition. The test conditions for verifying the AETF controls and measurement devices were deduced from 1D analysis and CFD calculation results. The spike-cone driving part was designed to withstand the applied aero-load, and satisfy the axial traversing speed of 10 mm/s at whole operation envelops.

• Structural Engineering and Mechanics
• /
• v.83 no.5
• /
• pp.655-669
• /
• 2022

Passive vibration control devices like tuned liquid column dampers (TLCD) not only significantly reduce buildings' vibrations but also can serve as a water storage facility. The recently introduced modified form of TLCD known as tuned liquid column ball damper (TLCBD) suppressed external vibration efficiently compared to traditional TLCD. For excellent performance, the mass ratio of TLCBD should be in the range of 5% to 7%, which does not include the mass of the ball. This additional mass of the ball increases the overall structure mass. Therefore, in this paper, an effort is made to reduce the mass of TLCBD. For this purpose, a new modified version of TLCBD known as tuned liquid column hollow ball damper (TLCHBD) is proposed. The existing mathematical modeling of TLCBD is used for this new damper by updating the numerical values of the mass and mass moment of the ball. Analytically the optimal design parameters are obtained. Numerically the TLCHBD is investigated with a single degree of freedom structure under harmonic and seismic loadings. It is found that TLCHBD performance is similar to TLCBD in both loadings' cases. To validate the numerical results, an experimental study is conducted. The mass of the ball of TLCHBD is reduced by 50% compared to the ball of TLCBD. Both the arrangements are studied with a multi-degree of freedom structure under harmonic and seismic loadings using a shake table. The results of the experimental study confirm the numerical findings. It is found that the performance behavior of both the dampers is almost similar under harmonic and seismic loadings. In short, the TLCHBD is lighter in weight than TLCBD but has a similar vibration suppression ability.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.26 no.3
• /
• pp.21-28
• /
• 2022

The TMD has a simple structure than other vibration control devices and shows excellent control performance for the simple harmonic vibration generated in the structure. However, the vibration control range is narrower than other control devices, making it vulnerable to vibration cycles caused by unexpected external loads. The ETMD developed in this study consisted of Mass with electromagnets. Therefore when supplying a current, the magnetic field is formed to increase the friction force with the friction plate, thereby instantaneously controlling the behavior of the Mass. The experiment was conducted to compare the control performance of the control device by installing the ETMD developed for control performance evaluation in the center of the model simple beam bridge to forced excitation at 3.02 Hz where the maximum bending displacement occurs. As a result of the experiment, ETMD exhibited excellent control performance with a maximum bending displacement attenuation rate of 57.51%.