• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.423-427
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• 2001

This paper describes a control scheme for direct torque and flux control of Induction machines using space vector modulation. The proposed predictive flux control scheme has directly calculated the reference voltage space vector based on Stator flux errors in order to control the torque and flux. This proposed control scheme has not the requirement of a separate current error, thereby improving transient performance and also has the advantage of less torque ripple in steady state with a fixed switching period. The effect of proposed method has been proven by simulations. It is concluded that the proposed control topology produces better results for steady state operation than the classical direct torque control.

• Proceedings of the KIPE Conference
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• 2001.12a
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• pp.15-18
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• 2001

This paper describes a control scheme for direct torque and flux control of induction machines. The proposed predictive flux control scheme has directly calculated the reference voltage space vector based on flux errors in order to control the torque and flux. This proposed control scheme has not the requirement of a separate current regulator and proportional-integral (PI) control of the flux, torque, and/or current error, thereby improving transient performance and also has the advantage of less torque ripple in steady state with a fixed switching period. The effect of proposed method has been proven by simulations and experiments.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.706-707
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• 2011

The insertion of the crowbar system in the doubly fed induction generator rotor circuit for a short period of time during grid disturbance enables a more efficient way of limiting transient rotor current and hence protecting the rotor side converter (RSC) and the DC - link capacitor. When crowbar is activated at fault occurrence and clearance time, RSC is blocked while DC -link capacitor and the grid side converter (GSC) can be controlled to provide reactive power support at the PCC and improve the voltage which helps to comply with grid codes. In this paper, control strategies for crowbar system to limit the rotor current during fault is presented with RSC and GSC controllers are modified to control PCC voltage during disturbance to enhance DFIG wind farm to comply with some strict grid codes. Model simulated on MATLAB/Simulink verify the study through simulation results presented.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.343-346
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• 1996

A new method for on-line induction motor fault detection is presented in this paper. This system utilizes unsupervised-learning clustering algorithm, the Dignet, proposed by Thomopoulos etc., to learn the spectral characteristics of a good motor operating on-line. After a sufficient training period, the Dignet signals one-phase ground fault, or a potential failure condition when a new cluster is formed and persists for some time. Since a fault condition is found by comparison to a prior condition of the machine, on-line failure prediction is possible with this system without requiring information on the motor of load characteristics.

• Journal of Veterinary Clinics
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• v.1 no.1
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• pp.49-52
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• 1984

Ponies were administered at the level of 0.1mg per kg of body weight of acetylpromazine malate through the jugular vein. Sedative effect, clinical signs such as body temperature, and changes of red blood cell counts and serum glucose concentration were investigated. Sedation was induced 5 to 6 minutes after injection of acepromazine and sedative effect was lasted for 30 to 40 minutes. Responsive reactions, however, to external stimuli were remained. Change of body temperature was not observed and heart beat was increased at the stage of induction and respiratory rate was decreased during the sedative period. Red blood cell count was considerably decreased during sedation, and concentration of serum glucose showed a tendency to increase gradually from the induction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.527-533
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• 1998

An optimized PWM switching strategy for an induction motor voltage control is developed and demonstrated. Space vector modulation in voltage source inverter offers improved DC-bus utilization and reduced commutation losses, and has been therefor recognizedas the perfered PWM method, especially in the case of digital implementation. Three-phase invertor voltage control by space vector modulation consists of switching between the two active and one zero voltage vector by using the proposed optimal PWM algorithm. The prefered switching sequence is defined as a function of the modulation index and period of a carrier wave. The sequence is selected by suing the inverter switching losses and the current ripple as the criteria. For low and medium power application, the experimental results indicate that good dynamic response and reduced harmonic distortion can be achieved by increasing switching frequency.

• BMB Reports
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• v.29 no.6
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• pp.564-568
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• 1996

Bursts of ethylene production occurred in twice at an early exponential (EEP) and prestationary (PSP) phases, respectively, during growth of callus tissue isolated from the root of soybean seedlings. The second burst of ethylene production at PSP was smaller in magnitude than the earlier one at EEP, but was followed by increases in both guaiacol peroxidase (GuPOX) and ascorbate peroxidase (AsPOX). The increase in AsPOX activity was also preceded by an increase in lipoxygenase (LOX) activity. Treatment of the tissue with the ethylene antagonist 2,5-norbonadiene (NBD) resulted in substantial reduction in LOX and AsPOX activities during this period. GuPOX activity was reduced only slightly, if any, by NBD. Role of ethylene in the sequential induction of LOX and AsPOX in senescing callus tissue is discussed.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.426-429
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• 2001

This paper describes a control scheme for direct torque and flux control of induction machines. The proposed predictive flux control scheme has directly calculated the reference voltage space vector based on flux errors in order to control the torque and flux. This proposed control scheme has not the requirement of a separate current regulator and proportional-integral (PI) control of the flux, torque, and/or current error, thereby improving transient performance and also has the advantage of less torque ripple in steady state with a fixed switching period. The effect of proposed method has been proven by simulations.

• Korean Journal of Acupuncture
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• v.25 no.1
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• pp.51-60
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• 2008

Objectives : The aim of this study was to investigate the mechanism and the clinical significance of prohibition of acupuncture of LI4 and SP6 during the period of pregnancy. Methods : It was investigated the prohibition of acupuncture during the period of pregnancy based on the literature reviews. Previous studies identified the acupuncture treatment of animal and clinical studies during the period of pregnancy and labor in China Academic Journal(CAJ). These papers were classified and investigated to clarify the rationale of the prohibition of acupuncture during the period of pregnancy. Results and Conclusions : The contraindicated points during the period of pregnancy are Hapgok (LI4), Samumgyo (SP6), Songmun (CV5), Kwanwon (CV4), Sosang (LU11), Chium (BL67), Kollyun (BL60). The uterine contraction can be induced by the stimuli of Hapgok (LI4) via endocrine system and Samumgyo (SP6) via nervous system. Both Hapgok (LI4) and Samumgyo (SP6) also can be used in various diseases such as induction of abortion, facilitation of parturition, stabilization of embryos, cross birth and so on.

• Journal of Korean Library and Information Science Society
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• v.25
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• pp.109-141
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• 1996

This research pertains to the interpretation of the many characteristics of the growing process of Library and Information Science in Korea with respect to its connection with discussion of the system of discipline. The result of the research are as follows. The Library and Information Science in Korea has gone through three distinct stages. The first stage spans the period from the late 50s to the 1960s during which three was an attempt to establish a relatively independent system of scholarship of Library and Information Science, although it was still heavily reliant on scholarship from Japan and the United States. The main characteristics of this first period is, firstly, that there a n.0, ppeared, for the first time, an awareness of a need to escape the attitude of foreign-orientation and to develop our own scholarship. Secondly, an effort was made to constitute the scholarship as a science (social science). Thirdly, there began a faint effort to import and a n.0, pply Information Science. The second stage covers the period between the 70s and the 80s, and saw the induction of Information Science begin in earnest and become the subject of education and research. The period was also marked by exploration of an alternative term to "Library Science", which was at the time being used. In addition, the period was a time of confusion for the examination of scholarship due to the induction of the new field of Information Science to what had already been a fragile structure of scholarship. This phenomenon served to intensify the doubts which had surfaced about existing term of Library Science, and ultimately played a large role in the a n.0, ppearance of the new term of Library and Information Science. Of course, there were a number of reasons which had made the change of term difficult, but it and be seen that the term change began in earnest after the change was adopted in the names of the university departments associated with the field in the late 80s. The third stage covers the period after the begining of the 90s. This stage saw the prominence of criticism and self-examination of the existing distorted foundational structure of Library and Information Sciences in Korea at the time, and, at the same time, a new methodology or research paradigms were advocated. It was a presenation of a new way of achieving a "Korean Library and Information Science" in order to understand and overcome not only the problems within the Korean libraries, but also within Library and Information Science in Korea. This caused repercussions to be felt not only among academics, but also among those actually working within the library systems. It moved academics toward a more practical scholarship, it inspired the prominence of a new scholarly methodology called a reform in academic writing, and even influenced specific research activities.research activities.