• The Korean Journal of Pain
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• v.11 no.2
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• pp.263-267
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• 1998

Background: This study was designed to know the dose requirement, analgesic efficacy and side effects of butorphanol and nalbuphine when administered with ketorolac by patient controlled analgesia (PCA) after total abdominal hysterectomy. Methods: Forty women who underwent total abdominal hysterectomy received ketorolac (bolus dose 2.4 mg, lockout interval 10 min) with either butorphanol (bolus dose 0.1 mg) or nalbuphine (bolus dose 1 mg) using PCA pump postoperatively. Results: Total amounts of 48 hr consumption were 8.7 mg (butorphanol)and 61.5 mg (nalbuphine). There were no significant differences between two groups in total ketorolac infusion doses, VAS score and side effects. Conclusions: Both butorphanol and nalbuphine were useful for PCA for postoperative pain control. We may suggest that ketorolac 180 mg with butorphanol 9 mg or nalbuphine 70 mg would be useful for 48 hr postoperative pain control.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.229-238
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• 2009

In this paper, AWS ECU test method, which is considering behavior of a Bi-modal tram, is described. In order to evaluate the performance of an electronic automotive ECU, the method which combines HILS (Hardware In the Loop Simulation) and RBT (Requirement Based Testing) is introduced. HILS is the method to predict the behavior of a vehicle adopting an ECU. The behavior of a Bi-modal tram can be analyzed by using the vehicle dynamic model. Requirement Based Testing compare the outputs of a real system with a virtual electronic unit (oracle) which created by the requirements. Rear axles of the Bi-modal tram are independently controlled by two AWS ECU. Especially, swing out can happen when an articulated vehicle is operated in the curved road. Therefore dynamic behaviour of a Bi-modal tram is considered at this situation. Through this study, the reliability of ECU can be verified economically and safely using the proposed test method before conducting the track test.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.382-384
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• 2008

Hold-up time is a special requirement for the front end DC/DC converter in a server power supply. It forces the converter with the variable switching frequency to operate in a wide switching frequency range, which makes the regulation difficult and reduces the power density. In this paper a novel frequency controlled half bridge converter with the hold-up time extension circuit is proposed. During the hold-up time, the auxiliary switches are turned on, thus the resonant inductance is reduced and the voltage conversion ratio is increased. Therefore, the output capacitor of the power factor correction (PFC) circuit can be decreased, and the converter can have high power density. The proposed converter is verified by experimental results from a prototype with 700W, 400V input, and 12V output.

• Journal of Power Electronics
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• v.9 no.3
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• pp.403-409
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• 2009

Automatically tuned passive filters can improve power quality to a great extent in power systems. A novel three-phase shunt auto-tuned filter is designed to effectively compensate source current harmonics and to provide reactive power required by the non-linear load, which draws a highly reactive, harmonic-rich current from the supply. An artificial neural network (ANN) based controller selects filter component values in accordance with reactive power requirement and harmonic compensation. Traditional passive filters are permanently connected to the system and draw large amounts of source current even under light load conditions. By using auto-tuned filters, the passive filter components can be controlled according to load variations and, hence, draw only required source currents. The selection is done by the ANN with the help of a properly tuned knowledge base to provide instantaneous compensation using a digital controller.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.51-54
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• 2002

As digital systems continue to use components with faster edge rate and clock speeds, transmission of the digital information can take place many troubles. The increasing requirement for controlled impedance PCBs becomes both a critical success factor and a design challenge. Especially, the noise sources in digital system include the noise in power supply, ground and packaging due to simultaneous switching of signal, signal reflections and distortions on single and multiple transmission lines. This paper simulates the tracks controlled impedance with the test coupon. So, it can saves the design time and supports the economical PCB design.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1039-1041
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• 2000

To obtain a high performance in a vector controlled induction machine, it is essential to know the instantaneous position of the rotor flux which depends on the rotor time constant. But the rotor time constant mainly varies due to the temperature rise in the motor winding, so real time compensating algorithm is necessary. This paper proposes that it uses short duration pulses added to the constant flux command current and then resultant torque command current produced by speed controller is utilized for the rotor resistance estimation. This method has advantages with a low computational requirement and does not require voltage sensors. The proposed method is proved by simulations.

• Journal of Wind Energy
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• v.2 no.1
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• pp.74-81
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• 2011

This paper deals with the application of LQ control to the power curve tracking control of wind turbine. However, two more additional tasks are required to apply the LQR theory to wind turbine control. One is the tracking problem instead of regulation, because the wind turbine is controlled as variable speed and variable pitch. The other is LQ integral control., because the rotor speed should be tightly controlled without any steady state error. Starting from the analysis of wind characteristics, design requirement of a wind turbine control system is defined. A design procedure of LQ tracking with integral control is introduced. The performance of LQ tracking system is analyzed and evaluated by numeric simulation.

• The Korean Journal of Pain
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• v.12 no.1
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• pp.21-26
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• 1999

Background: Preoperative blocking of surgical nociceptive inputs may prevent sensitization of central nervous system (CNS) and reduce postoperative pain. The stress responses to surgical trauma consist of increase in catabolic hormones and decrease in anabolic hormones. We studied whether preoperative low dose epidural bupivacaine and morphine could affect postoperative pain, changes plasma cortisol, and serum glucose. Methods: Thirty patients undergoing total abdominal hysterectomy were randomly assigned to one of three groups. General anesthesia was induced in all patients and after that, epidural blocks were done except the control group (n=10) patients. Preoperative block group (n=10) received 0.5% bupivacaine 50 mg and morphine 2 mg epidurally as a bolus before operation and followed by 0.1% bupivacaine $5\;mghr^{-1}$ and morphine $0.2\;mghr^{-1}$ for 10 hours. Postoperative block group (n=10) received the same doses of bupivacaine and morphine under the same method postoperatively. Postoperative pain relief was provided with i.v. fentanyl through Patient-Controlled-Analgesia Pump. Postoperative pain by visual analogue scores (VAS), analgesic requirement (first requirement time, total amounts used), side effects, plasma cortisol level and serum glucose level were compared. Results: Until postoperative 6 hrs, VAS of control group was higher than those of the epidural groups. No difference was observed in VAS between the two epidural groups. First analgesics requirement time and total amounts of used analgesics were not different between the two epidural groups, but first analgesic requirement time of preoperative block group was significantly prolonged compared with control group. Plasma cortisol and serum glucose levels were not different among groups. Conclusions: Low dose preoperative epidural bupivacaine and morphine could not reduce postoperative pain, plasma cortisol level and serum glucose level compared with postoperative block group.

• Earthquakes and Structures
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• v.6 no.6
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• pp.647-664
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• 2014

A reduction of the response of irregular structures subjected to earthquake excitation by control devices equipped by suitable control algorithm is proposed in this paper. The control algorithm, which is used, is the pole placement one. A requirement of successful application of pole placement algorithm is a definition-selection of suitable poles (eigen-values) of controlled irregular structures. Based on these poles, the required action is calculated and applied to the irregular structure by means of control devices. The selection of poles of controlled irregular structure, is a critical issue for the success of the algorithm. The calculation of suitable poles of controlled irregular structure is proposed herein by the following procedure: a fictitious symmetrical structure is considered from the irregular structure, adding vertical elements, such as columns or shear walls, at any location where is necessary. Then, the eigen-values of symmetrical structure are calculated, and are forced to be the poles of irregular controlled structure. Based on these poles and additional damping, the new poles of the controlled irregular structure are calculated. By pole placement algorithm, the feedback matrix is obtained. Using this feedback matrix, control forces are calculated at any time during the earthquake, and are applied to the irregular structure by the control devices. This procedure results in making the controlled irregular structure to behave like a symmetrical one. This control strategy can be applied to one storey or to multi-storey irregular buildings. Furthermore, the numerical results were shown that with small amount of control force, a sufficient reduction of the response of irregular buildings is achieved.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.1-6
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• 2008

The performance of shock absorber is directly related to the car behavior and performance, both for handling and comfort. Most of compact car are assembled the passive shock absorber for cost effect but some of compact driver want better performance of shock absorber than standard parts. Therefore, they want the semi-active suspension control system instead of standard damper system. But they only can change the mechanical damping control shock absorber at A/S market. The mechanical damping control shack absorber can not vary the damping force in driving condition so they do not satisfy the mechanical damping control shock absorber system. In this study, electrically damping force controlled shock absorber system is developed based on the mechanical damping force control damper system. This system can vary damping force by switch on dashboard in driving condition. And, this system can satisfy the requirement of tuning market. Therefore, it is expected the system to show the engineering capability of korean damper company and to increase export market share to oversea damper market.