• Journal of Institute of Control, Robotics and Systems
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• v.15 no.3
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• pp.249-254
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• 2009

This paper studies the problem of pole placement by an LQ controller for system having two distinct real poles. Using the so-called Pole's Moving Range (PMR) drawn in the s-plane and relational equations between closed-loop system poles and weighting matrices, we calculate the state weighting matrix to move two distinct real poles to a pair of complex poles. By numerical examples, we show that the proposed method is applied to improve system performance.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2001.11a
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• pp.181-185
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• 2001

This paper presents a digitally speed sensorless control system for induction motor with direct torque control (DTC). The drive is based on Mode1 Reference Adaptive System (MRAS) using state observer as a reference model fat flux estimation. The system are closed loop stator flux and torque observer for wide speed range that inputs are currents and voltages sensing of motor terminal, model reference adaptive control (MRAS) with rotor flux linkages for the speed turning aignal at low speed range, two hysteresis controllers. The Proposed system is verified through simulation.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.535-535
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• 2000

This paper presents an adaptive receding horizon H$_{\infty}$ controller for the linear parameter varying systems in the deterministic environment, which combines a parameter range estimator and a robust receding horizon H$_{\infty}$ controller using the parameter bounds. Using parameter set inclusion and terminal inequality condition, the closed-loop system stability is guaranteed. It is shown that the stabilizing adaptive receding horizon H$_{\infty}$ controller guarantees the H$_{\infty}$ norm bound.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.31 no.11
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• pp.146-154
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• 1982

This paper proposes a new circuit for the CDI system to have a constant ignition power at the engine speed range of 500 to 7500 rpm and the battery voltage range of 12 to 16 volts in the 4-cylinder automobile. The proposed CDI system has a closed-loop with a PWM DC-DC converter controlled by the error signal between capacitor voltage and reference voltage. In order to decrease the capacitor charging time, the primary winding of ignition coil is made to be shorted during capacitor charging. An experimental suystem is fabricated and the results obtained thereof are found to be satisfactory.

• Bulletin of the Korean Mathematical Society
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• v.26 no.1
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• pp.31-34
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• 1989

In this paper we show that if there is a derivation on a commutative Banach algebra which has a non-nilpotent separating space, then there is a discontinuous derivation on a commutative Banach algebra which has a range in its radical. Also we show that if every prime ideal is closed in a commutative Banach algebra with identity then every derivation on it has a range in its radical.

• Communications of the Korean Mathematical Society
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• v.11 no.4
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• pp.959-965
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• 1996

In this paper we study the index stability theorem for a bounded linear operator with closed range and extend the Kato's decomposition theorem for an absence of the index.

• Journal of Korean Foot and Ankle Society
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• v.10 no.1
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• pp.71-75
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• 2006

Purpose: To evaluate the results of treatments by percutaneous Acutrak screw fixation for intra-articular tongue type fracture of calcaneus, especially in elderly patient or patients with underlying disease including diabetes mellitus. Materials and Methods: Seven cases with intra-articular tongue type fracture of calcaneus, from November 2003 to February 2005, were reviewed. There were 6 males and 1 female with 65 years old mean age (range: $61{\sim}71$ years old). The average follow-up period was 16 months (range: $10{\sim}25$ months). Two Steinmann pins were used for closed reduction. After closed reduction was done like Essex-Lopresti's method, two Acutrak screws were inserted. The third Acutrak screw was inserted at the sustentaculum tali away from sinus tarsi to fix the primary fracture line. The patients were evaluated with Salama scale, the extent of recovery of Bohler angle, state of subtalar joint. Results: Clinical results according Salama scale were excellent in 5 cases, and good in 2 cases. Average preoperative Bohler angle was $13^{\circ}$ (range: $12{\sim}15^{\circ}$). Average postoperative Bohler angle was 31o (range: $23^{\circ}-40^{\circ}$). There were no soft tissue complications. There were two mild subtalar arthritis. Conclusions: We think that percutaneous Acutrak screw fixation is a good option for tongue type fracture of calcaneus in elderly patient or patients with underlying disease including diabetes mellitus.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.4
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• pp.93-103
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• 2016

PURPOSE: The purpose of this study is to determine the effect of therapeutic exercise on pain, range of motion and strength, and balance ability in a patient with an anterior ankle impingement (AAI). METHODS: A-32-year-old male presented limited ankle motion and pain with forced dorsiflexion at both ankle joints. In response, a therapeutic exercise program consisted of ankle joint mobilization, strength exercises using an elastic band, and proprioceptive exercises including semi-squats and a one-legged standing exercise with open and closed eyes. The program was performed for 40 min/day, twice per week, for 8 weeks. Pain, range of motion (ROM), and muscle strength (ankle dorsiflexion, plantarflexion, inversion, and eversion), as well as a one-legged standing test of both ankles, were measured before and after 4 and 8 weeks of therapeutic exercise. RESULTS: VAS decreased in both ankles after 8 weeks of exercise, respectively, compared to baseline levels. Range of motion and strength increased in both ankles for dorsiflexion, plantarflexion, inversion, and eversion after 8 weeks of exercise compared to baseline levels. In addition, the ability to perform a one-legged standing test with eyes opened and closed improved in both legs after 8 week of exercise compared to baseline levels. CONCLUSION: These results suggest that therapeutic exercise improves pain, ROM, muscle strength, and balancing ability in patients with AAI.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.10
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• pp.1388-1394
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• 2018

In this paper, the improvement of the control response by using the error compensator to improve the stability of the control in the power conversion system is verified. Typically a closed loop control method is used to improve the control response characteristics in a traditional power conversion system and this is accomplished by generating a PWM waveform. In this paper, the newly constructed Type3 compensator to overcome the existing such as PI controller or Type2 compensator has been developed to improve the control stability of these closed loop control systems and the effectiveness of the use of error compensation devices was verified by presenting technique to improve stability and select its parameters by expanding the range of phase gains. Stability improvements are shown by the extension of the phase gain range and parameter selection techniques and the effects of using the error compensation device are verified accordingly.

• Phonetics and Speech Sciences
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• v.9 no.4
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• pp.107-114
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• 2017

The purpose of the current study was to compare selected acoustic and electroglottographic measures (closed quotient, pitch, and loudness) among vowel phonation, traditional voiced lip trill ($VLT_T$), modified voiced lip trill methods ($VLT_M$). A total of 21 participants without voice complaints produced 4-second long samples using each phonation method. Results indicated that mean closed quotient of $VLT_M$ was higher than that of vowel phonation and $VLT_T$, while its range and standard deviation measures were higher than those of vowel phonation. Mean, range, standard deviation, maximum of pitch measures of $VLT_M$ were higher than those of vowel phonation. Lastly, mean and maximum loudness of the $VLT_M$ were higher than $VLT_T$. In conclusion, the current data indicate the possibility to use the $VLT_M$ as a training method for singing or a strategy to facilitate generalization effect of voice therapy. Current results also reflect the necessity for further study pertaining to the long-term effect of the $VLT_M$ training method. Clinical implications are discussed.