• Journal of Power Electronics
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• 제5권1호
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• pp.20-28
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• 2005

This paper presents a fuzzy predictive sliding mode control for high performance induction motor position drives. A new simplified inner-loop sliding-mode current control scheme based on a nonlinear mathematical model of an induction motor is introduced. Novel predictive fuzzy logic PI and PID controllers are used in speed and position loops, respectively. Sliding-mode current controllers and fuzzy predictive logic controllers are designed based on indirect vector control. The overall system performance is examined under different dynamic operating conditions. The performance of the drive system is robust and stable, and insensitive to parameters and operating condition variations even though non-exact system parameters are used in the implementation of the proposed controllers.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권7호
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• pp.346-353
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• 2000

In this paper, a fuzzy logic controller is designed for position control of an Arage disk. The Arage disk system is an experimental set to exploit Arago's disk phenomenon which is the operation principle of induction motors. Since the Arage disk system operates in stable, maginally stable, and unstable regions, it is suitable as a test system to evaluate efficiency of various control system design methods. It is shown that the fuzzy logic controller shows good responses for multi-operating points of Arage disk system, while the controllers using linearized models are able to control the system on only one operating point.

• 융복합기술연구소 논문집
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• 제2권1호
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• pp.43-48
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• 2012

Generally, in-plane position of moving object is measured referring to the reference pattern attached to the object. From optical camera to magnetic reluctance probe, there are many ways detecting a variation of the periodical pattern. In this paper, the various operating principles developed for in-plane positioning are reviewed and compared each other. And, a novel method measuring large rotation as well as x, y linear displacements is suggested, including a detailed description of the overall system layout. It is a modified version of the surface encoder, which is a robust digital measuring method. From the surface encoder, the rotation of an object is measured indirectly through a compensated input of optical servo and independently of linear displacements. So, the operating range can be extended simply by enlarging the reference pattern, without magnifying the decoding units.

• Journal of Power Electronics
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• 제8권3호
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• pp.268-274
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• 2008

This paper presents a proposed position controller for a vector controlled induction motor. The position controller design depends on the rotational motion equations and a classical speed controller (CSC) performance. The CSC is designed to have the ability to track variable reference inputs and to provide a predefined system performance. Standard position controller in industry is presented to analyze its performance and its drawbacks. Then the proposed position controller is designed, based on the well defined rotational motion equations. The proposed position controller and the CSC are applied to control the position and speed of the vector controlled induction motor with different ratings. Simulation results at different operating conditions are presented to evaluate the proposed controllers' performance. The results show that the CSC can drive the motor with a predefined speed performance and can track a variable reference speed with an approximately zero steady state error. The results also show that the proposed position controller has the ability to effect high-precision positioning in a limited time and to track a variable reference position with a zero steady state error.

• 제어로봇시스템학회논문지
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• 제17권7호
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• pp.634-640
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• 2011

When a servo position controller of a robot or a driving units is composed of a PID controller, servomechanism which is modelled is composed of current, velocity and position control loops. After this model is simulated, the technique operating gain of each controller is suggested. The model consists of current, velocity and position controllers from the inside to the outside gradually. Also, to combine velocity and position controllers with 2 order system, simulation is performed after current controllers are composed, which are able for current loop to work ideally. If a current controller is treated with constant, it is possible for velocity and position controller to consist of controller into 2 order system. The technique is verified by applying T-company servo motor which is much more applied to current, velocity and position controller robots.

• 한국치위생학회지
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• 제7권4호
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• pp.381-393
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• 2007

The objectives of this study was to suggest for prophylatic of Musculoskeletal system disorders in Dental Hyginists and Dental hygiene students to maintain good posture in the dental hygiene curriculum. This study was carried with 100 dental hygienists in "M" city located in Jolla Province and 82 college students majoring in dental hygiene. The results were as follows: 1. During the operators' medical treatment, 41.7% answered that the patients' head was located in the operators' chest during their treatment. Also, 58.3% answered that the patients' head was located in the operators' abdomen. For this reason, 81.3% said that the patients' mouth became close to the operators' eyes - less than 30cm. And 65.1% said that they performed an operation in various directions. 2. The most common posture -between the position of operating and the position of assisting- is the position of operationg 1. The position of operationg 1 and 5 have an effect on the waist, and the position of assisting 3 has an effect on pains of the waist, bottoms, knees, ankles and feet. 3. The common symptoms of musculoskeletal system disorders in dental hygienists and student was the neck ache and the shoulders, and was followed by the lower back. From the cases that they visited in health care or apothecary to the above pain, symptoms were highest in the shoulders(18.3%) and were followed by the lower back(13.4%) and neck(9.1%). 4. On The necessity of education related to, According to researches, 96.3% college students and 92.5% dental hygienists answered that education related to Musculoskeletal system disorders is necessary. 5. In this study, I have 3 limitations. First, the subject of survey was selected for specific people in the specific city, Second, the personal judgment was made in judging the relations of the position of operating, the position of assisting and the aches. Third, the relations of the position of operating, the position of assisting and the aches don't have supporting medical evidences. Therefore, this study will be carried on more people with more objectives and medical method.

• 임상간호연구
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• 제17권2호
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• pp.204-214
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• 2011

Purpose: This study was aimed to provide information on the awareness of patient safety culture and safety care activities among operating room (OR) nurses and to analyze the factors influencing the safety care activities. Methods: For this descriptive research, self-reported questionnaires were administered to 168 OR nurses who were working at the university-affiliated and general hospitals. The collected data were analyzed using descriptive statistics, t-test, ANOVA, $Scheff{\grave{e}}$ test, Pearson's correlation coefficient and Stepwise multiple regression with SPSS/WIN 17.0. Results: The mean score of the awareness on patient safety culture was 3.27 out of 5 points and that of safety care activity was 4.31 out of 5. The statistically significant difference was found between experience of safety education and the awareness on patient safety culture. Also, the scores of safety care activities were significantly different according to OR nurses' position, education levels, and experience of safety education. There was a positive correlation between the awareness of patient safety culture and safety care activity. Their explanatory power on safety care activity was 8.8%, which includes working environment in operating room 3.3% and nursing position 5.5%. Conclusion: Compared to the level of patient safety activities, the OR nurses' awareness on patient safety culture was low. Given the specific characteristics and conditions in each hospital, it needs to increase the OR nurses' awareness on patient safety culture and activities related to patient safety.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권3호
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• pp.180-185
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• 2012

Purpose: An accurate preoperative analysis of the patient is essential in orthognathic surgery in order to acquire superior results. In profile, the location of the chin's position may change according to the neck's inclination. This may ultimately affect the amount of surgical movement. During acquisition of cephalometric radiographs, or in supine position, there is a discrepancy in the neck's inclination. This means that there are also various discrepancies between the actual profile and the various preoperative profile images. In the clinical situation, the decision in performing genioplasty usually lies in the analysis of the patient's profile on the operating table at the final stages of orthognathic surgery. This study aims to analyze the different preoperative profile images and to compare their discrepancies. Methods: Fifty eight patients undergoing orthognathic surgery were chosen. These patients were divided into three groups according to angle's classification of malocclusion, as class I, II or III. The right profile of these patients in centric occlusion was taken in natural head position (NHP). This was set as the 'actual profile image.' Another right profile image was taken on the operating table after insertion of the nasotracheal intubation and with muscle relaxants in effect. This was also taken in centric occlusion. The angle (denoted 'A') between the soft tissue glabella-pognion and the true vertical plane was found in the above-mentioned profile images and in the cephalometric radiographs. The differences of these values were analyzed. Results: There were differences in Angle 'A' in all of the preoperative images. These values were however, not statistically significant. Conclusion: In order to gain an esthetic profile during orthognathic surgery, the NHP is shown to be the most reliable position. Images reproducing such head positions should be used in the treatment planning process.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.98-100
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• 1994

Shaft position sensing is essential in Switched Reluctance Motor(SRM) in order to synchronize the phase excitation pulses to the rotor position. In low cost application, particularly at low power level, the shaft position sensor is too costly. This paper describes low cost SRM drive system that can control torque and speed utilizing a optointerrupter with slotted disc. The validity of the proposed scheme is verified by experimental results for 6/4 SRM drive system.

• Journal of Magnetics
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• 제19권1호
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• pp.90-100
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• 2014

Position estimation that uses only active phase voltage and current is presented, to perform high accuracy position sensorless control of a SRM drive. By extracting the amplitude of the first switching harmonic terms of phase voltage and current for a PWM period through Fast Fourier Transform (FFT), the flux-linkage and position are estimated without external hardware circuitry, such as a modulator and demodulator, which result in increased cost, as well as large position estimation error, produced when the motional back EMF is ignored near zero speed. A two-phase SRM drive system, consisting of an asymmetrical converter and a conventional closed-loop PI current controller, is utilized to validate the performance of the proposed position estimation scheme in comprehensive operating conditions. It is shown that the estimated values very closely track the actual values, in dynamic simulations and experiments.