• 제어로봇시스템학회논문지
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• 제19권11호
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• pp.991-997
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• 2013

In this paper, we propose a CFWC (CCD and fuzzy PID based width control) scheme to obtain the desired delivery width margin of a vertical rolling mill in hot strip process. A WMS(width measurement system) is composed of two line scan cameras, an edge detection algorithm, a glitch filter, and so on. A dynamic model of the mill is derived from a gauge meter equation in order to design the fuzzy PID controller. The controller is a self-learning structure to select the PID gains from the error and error rate of the width margin. The effectiveness of the proposed CFWC is verified from simulation results under a width disturbance of the entry in the mill. Using a field test, we show that the performance of the width control is improved by the proposed control scheme.

• Journal of Electrical Engineering and Technology
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• 제8권1호
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• pp.70-79
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• 2013

In this paper, a comparative study on the frequency estimation methods using IRDWT (Improved Recursive Discrete Wavelet Transform), FRDWT(Fast Recursive Discrete Wavelet Transform), and GCDFT(Gain Compensator Discrete Fourier Transform) is presented. The 345[kV] power system modeling data of the Republic of Korea by EMTP-RV is used to evaluate the performance of the proposed two kinds of RDWT(IRDWT and FRDWT) and GCDFT. The simulation results show that the frequency estimation technique based on FRDWT could be the optimal frequency measurement method, and thus can be applied to FDR(Fault Disturbance Recorder) for wide-area blackout protection or frequency measurement apparatus.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.268-272
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• 2014

This letter presents a measurement methodology of the complex permittivity of liquid using a partially open cavity in narrow band. The partially open cavity (POC) can measure dielectric small changes caused by the temperature variation of the liquid inside the cavity as well. Using the resonance frequency and unloaded quality factor of the proposed POC, the complex permittivity is evaluated. The apertures on the walls of the cavity are designed to circulate the liquid inside to outside of the POC and located at the corner area of the cavity to minimize the disturbance of field distribution at the dominant mode. The results measured by the proposed POC were compared with those by the conventional open-ended probe and Cole-Cole equation. The POC showed better performance in measuring small dielectric constant changes than the open-ended probe.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.900-903
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• 2014

Fly-wheel, Gimbal antenna, CMG, Spaceborne cyrocooler generate micro-vibration during their on-orbit operation as well as implementing their own function. To comply with the mission requirement of high resolution observation satellite, additional technical efforts have been required to isolate the micro-vibration derived from such payloads by applying the vibration isolator. In this study, we proposed a passive isolator using SMA mesh washer, which guarantees the structural safety of both micro-vibration disturbance source and itself under harsh launch vibration loads without an additional holding mechanism and the micro-vibration isolation performance on orbit environment. To verify the micro-vibration isolation performance of the proposed vibration isolator, we performed the micro-vibration isolation measurement test using the dedicated micro-vibration measurement device proposed in this study.

• 제어로봇시스템학회논문지
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• 제6권7호
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• pp.529-536
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• 2000

A robust controller to attenuate the various disturbances of tandem cold mills (TCM) is synthesized by measurement-feedback $H_{\infty}$ control techniques which can reflect the input direction of disturbances and the knowledge of entry thickness variation (disturbance) is synthesized by discrete-time measurement-feedback $H_{\infty}$ control theory. It is demonstrated that the $H_{\infty}$ preview control gain can be easily obtained by the seperation principle of the control and estimation problems in $H_{\infty}$ control. Finally the effectiveness of the proposed control method for TCM is evaluated by the computer simulation and compared to the other control methods which have been previously studied.

• 한국정밀공학회지
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• 제14권9호
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• pp.15-21
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• 1997

In this paper, a self-activated cable spooling system for seaborne winch is developed . The system consists of a hydraulic servo driving unit and a cable position measurement mechanism. To realize the cable spooling system, it is carried out the mathematical modelling of the system and designed the proportional controller through the system aalysis and the simulation. The cable spooling system is tested and evaluated to validate the performance of the controller. The test results shows a good traceability of the cable spooling system under disturbance of cable tension.

• International Journal of Control, Automation, and Systems
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• 제6권3호
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• pp.453-459
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• 2008

The neural network is currently being used throughout numerous control system fields. However, it is not easy to obtain an input-output pattern when the neural network is used for the system of a single feedback controller and it is difficult to obtain satisfactory performance with when the load changes rapidly or disturbance is applied. To resolve these problems, this paper proposes a new mode to implement a neural network controller by installing a real object for control and an algorithm for this, which can replace the existing method of implementing a neural network controller by utilizing activation function at the output node. The real plant object for controlling of this mode implements a simple neural network controller replacing the activation function and provides the error back propagation path to calculate the error at the output node. As the controller is designed using a simple structure neural network, the input-output pattern problem is solved naturally and real-time learning becomes possible through the general error back propagation algorithm. The new algorithm applied neural network controller gives excellent performance for initial and tracking response and shows a robust performance for rapid load change and disturbance, in which the permissible error surpasses the range border. The effect of the proposed control algorithm was verified in a test that controlled the speed of a motor equipped with a high speed computing capable DSP on which the proposed algorithm was loaded.

• 지역사회간호학회지
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• 제13권3호
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• pp.423-432
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• 2002

This study was conducted to test the validity of characteristics of family nursing phenomena in Korea identified in a previous study by Yoon, S. Y, et al. (1999). Data for this study were collected from 355 (first measurement 186, second measurement 169) nurses whose family nursing careers were more than one year using a cross sectional survey method. The distribution per one characteristic ranged between 0 to 5. The phenomena that had two or more characteristics and had a score of 3.0 points or more included disturbance in marital role', 'disturbance in family communication', 'inappropriate family coping', 'lack of family intimacy', 'unhealthy life style', 'deficit of financial management skill and support', 'inadequate care management sick member', and' inadequate home-making'. The essential characteristics of the 8 phenomena presented above included 27 items. Further studies on family nursing phenomena in Korea are needed to support the evidence through surveys of families in the field. A reconfirmation study, as well as qualitative research on the low validity of the characteristics, needs to be more performed in the future.

• Journal of Yeungnam Medical Science
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• 제4권1호
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• pp.59-63
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• 1987

1. 기능성 소화기 장애증상이 있고 GET의 지연을 보였던 환자들의 GET 평균치는 22.49분으로 정상군 9.6분보다 유의하게 증가되어 있었으며 이를 환자수는 44명으로 88%에 해당하였다. 2. GFT지연군 15명에게 1단간 Cleboril을 투이한 결과 유의한 GET단축이 관찰되었으며 이중 11명(73%)에서는 현저한 단축소견이 있었다. 3. 기능성 소화기 장애증상을 호소하는 환자에서의 GET측정은 건강염려환자를 선별하는데 유용할 뿐만 아니라 간기능검사, 상부위상관, X-선촬영, 위내시경검사 및 경구담낭조영술 등에서 정상으로 확인된 환자에서 잠복된 소화기성 질환을 발견하는데도 유용하게 이용될 수 있을 것으로 사료된다.

• 대한기계학회논문집A
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• 제21권3호
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• pp.502-510
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• 1997

A disturbance rejection controller using eccentricity filtering and LQ control techniques is proposed to alleviate the effecto of major roll eccentricity in multivariable cold-rolling processes. Fundamental problems in multivariable cold-rolling processes such as process time delay inherent in exit thickness measurement and non-stationary characteristics of roll eccentricity signals can be overcome by the proposed control method. The filtered instantaneous estimate of roll eccentricity may be exploited to improve instantaneous estimate of the exit thickness variation based on roll force and roll gap measurements, and a feedforward compensator is augmented as a reference for a gaugemeter thickness estimator. LQ feedback controller is combined with eccentricity filter for the attenuation of the exit thickness variation due to the entry thickness variation. The simulation results show that the roll eccentricity disturbance is significantly eliminated and other disturbances also are attenuated.