• The Korean Journal of Pain
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• v.27 no.3
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• pp.210-218
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• 2014

Brachial plexus injury is a potential complication of a brachial plexus block or vessel puncture. It results from direct needle trauma, neurotoxicity of injection agents and hematoma formation. The neurological presentation may range from minor transient pain to severe sensory disturbance or motor loss with poor recovery. The management includes conservative treatment and surgical exploration. Especially if a hematoma forms, it should be removed promptly. Comprehensive knowledge of anatomy and adept skills are crucial to avoid nerve injuries. Whenever possible, the patient should not be heavily sedated and should be encouraged to immediately inform the doctor of any experience of numbness/paresthesia during the nerve block or vessel puncture.

• The Korean Journal of Pain
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• v.7 no.1
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• pp.65-68
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• 1994

Carpal tunnel syndrome is the most common compressive neuropathy of the upper extremity. Clinical manifestations include pain as well as motor and sensory dysfunction in the distribution of the median nerve. As nonoperative treatment, median nerve block is performed to relieve pain for carpal tunnel syndrome. We have experienced 5 such cases. Our results support median nerve block as an excellent treatment for carpal tunnel syndrome.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.517-518
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• 2023

최근 뇌-컴퓨터 인터페이스 분야에서는 뇌파 신호를 이용한 운동 심상 분류 연구가 활발히 이루어지고 있다. 뇌파는 개인별 차이가 큰 생체 신호로, 사용자에 독립적인 경우 추론이 어려워지는 문제가 있어 운동 심상 분류에서는 주로 피험자 종속적인 연구가 행해져 왔다. 본 논문에서는 컨볼루션 신경망 기반의 뇌파 분류 모델인 EEGNet 에 새로운 방식으로 개선한 Squeeze-and-Excitation block 을 적용해 피험자에 대해 독립적인 운동 심상 분류 성능을 향상시키는 방법을 제안하며, 제안한 Squeeze-and-Excitation block 을 적용한 모델이 기존 모델보다 높은 분류 성능을 보여주는 것을 실험적으로 확인하였다.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.137-143
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• 1998

Numerical simulation is conducted to clarify the heat transfer and fluid flow characteristics of traction motor for electric car SIMPLE algorithm based on finite volume method is used to make linear algebra equation. The governing equations are solved by TDMA(TriDiagonal Matrix Algorithm) with line-by-line method and block correction. From the results of simulation, the characteristics of cooling pattern is strongly affected by the size of hole in stator core. In the case of high rotational speed of rotor, temperature difference along the axial direction is more decreased than that of low rotational speed.

• The Korean Journal of Pain
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• v.14 no.1
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• pp.61-67
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• 2001

Background: Usually, lumbar epidural block is performed on the $L_{3-4}$ interspace. This study was designed to evaluate the analgesic efficacy and shortening of labor duration comparing the $L_{1-2}$ and $L_{3-4}$ interspace epidural blocks in nulliparous normal vaginal deliveries and then investigates side effects following the blocks. Methods: Eighty healthy nulliparous women were divided into two groups, $L_{1-2}$ (n = 40) and $L_{3-4}$ (n = 40). Epidural blocks, lumbar epidural block were performed at the $L_{1-2}$ and $L_{3-4}$ interspace with a catheter advancing 3 cm cephalad. The initial dose of 12 ml (0.167% bupivacaine, fentanyl $50{\mu}g$ and clonidine $75{\mu}g$) was injected epidurally at 4 cm dilatation of cervix and severe pain of labor. If a visual analogue scale (VAS) score was more than 4 points, an additional dose was administered epidurally using the same volume as the above mentioned, but with the exception that the bupivacaine was diluted to 0.1 percentage. The maternal blood pressure, pulse rate, respiration rate and fetal heart rate were measured at 10 min intervals for the first 30 min, at 15 min interval for the next 30 min and at 30 min interval for the last one hour following the blocks. The duration of the first (active) and second stages of labor was counted and the neonatal Apgar score was recorded at one and five min after delivery. The degree of motor block, pruritus, nausea and vomiting were also noted. Results: The patients in group $L_{1-2}$ had lower pain scores than group $L_{3-4}$ at 5, 20, 30, 60 mins. The duration of 1st and 2nd labor stage in the $L_{3-4}$ epidural block were $272{\pm}33.5$ min, $49.2{\pm}27.4$ min respectively but those in the $L_{1-2}$ epidural block were $253.5{\pm}32.5$ min, $37.3{\pm}22.3$ min, respectively. Conclusions: We concluded the analgesic efficacy and shortening of labor duration in $L_{1-2}$ epidural block was better than those in $L_{3-4}$ epidural block. Maternal hemodynamic change, motor block. pruritus, nausea, vomiting and Apgar score showed no significant differences between the two groups.

• Journal of the Semiconductor & Display Technology
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• v.9 no.1
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• pp.1-4
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• 2010

We investigated a linear carbon nanotube motor serving as the key building block for nano-scale motion control by using molecular dynamics simulations. This linear nano-motor, is based on the electrostatically telescoping multi-walled carbon-nanotube with ultralow intershell sliding friction, is controlled by the gate potential with the capacitance feedback sensing. The resonant harmonic peaks are induced by the interference between the driving frequencies and its self-frequency. The temperature is very important factor to operate this nanomotor.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.3
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• pp.136-142
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• 2001

In this research a Simulink/RTW-baed realtime control system was developed for an induction motor vector control. On the Simulink window, the control system is designed in the form of block diagrams, program codes are produced automatically with the RTW(Real Time Workshop), then an DSP c compiler compiles the program codes. With this automatic program producing method rapid prototyping is realized with the least time-consuming manual programming procedures. To show effectiveness of the proposed system designing scheme a DSP-based induction motor vector controller was constructed and implemented.

• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.295-303
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• 2013

This paper reports an investigation of pulse width modulation (PWM) techniques for two-phase brushless DC (BLDC) motors fed by a two-phase eight-switch inverter in a fan application. The three-phase BLDC motor is widely applied in industry; however, a lower-cost two-phase BLDC motor and drive circuit has been greatly in demand in recent years. In this paper, we introduce a mathematical model of the two-phase BLDC motor with sinusoidal back electromotive forces (EMFs) based on traditional three-phase BLDC motors. To simplify the drive algorithm and speed up its application, we analyze the principle of block commutation for a two-phase BLDC motor drive in the 180-electrical-degree conduction mode, and we further propose five PWM schemes to improve the commutation performance of the two-phase BLDC drive. The effectiveness of the proposed PWM methods is verified through experiments.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.294-295
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• 2007

80년대 초에 개발된 CD(Compact Disc) Disc는 지난 27여 년간 급속한 발전을 하였다. 95년에 DVD가 발표되면서 영화 Title제작이 되어 우리는 안방에서 고화질의 DVD를 감상할 수 있었다. CD-R(Recordable) 로부터 시작된 기록 기술은 CD-RW를 거쳐 DVD-Recordable, DVD-ReWritable 및 DVD-RAM, Light Scribe등 거쳐 BD(Blu-Ray) 기술에 까지 이르게 되었다. 광 Disc 기술은 3가지 분야로 나눌 수 있다. 안정된 제어를 위한 Servo 기술, Mechanical 기술, PC와communication 할 수 있는 Interface 기술 등으로 나눌 수 있다. Servo 제어 기술은 다음과 같이 4가지 분야로 구성되어 있다. Focus Servo, Tracking Servo, Sled Servo, Spindle Servo. Disc 회전을 제어를 담당하고 있는 Spindle Servo Block에서는 Hall Sensor를 이용하여 Disc의 회전을 Count하여 Feedback 하였다. 그러나 갈수록 심화 되고 있는 가격 경쟁 상황에서 Hall Sensor를 대체하여 회전수를 Conut하는 방법이 필요 하였다. BEMF(역기전력)을 이용한 Zero Crossing 방법이 이를 대체 하였지만, Motor의 전기적인 특성 편차 등에 안정된 control이 안되어서, Motor를 관리하는 방법으로 진행되어 왔다. 이것은 생산 Loss로 이어져서 Hall Sensorless의 장점을 훼손하게 되었다..본 논문에서는 이러한 Sensorless Type Spindle Motor의 문제점에 대해 Common 단자를 이용하여 안정된 제어 방법을 제안 한다. less Type의 문제점인 초기 기동 문제를 Common 단자를 이용하여 안정되게 Spindle motor를 Control 하는 방법에 대해 연구 하고자 한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.6
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• pp.525-537
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• 2001

In this paper a new space vector RPPWM(Random Position PWM) is proposed. In the propsed RPPWM each of three phase pulses is located randomly in each switching interval. Based on the Space vector modulation technique the duty ratio of the pulses is calculated Along with the randomization of the PWM pulses. we can obtain the effects of spread spectra of votlage, current as in the case of randomly changed switching frequency, To verify the validity of the proposed RPPWM simulation study was tried using Matlab/Simulink The main model described in Simulink block diagrams includes the space vector modulation block pulse position randomization block inverter block 3 phase induction motor block and so on By the simulation study, the harmonics of the output voltage and the current of inverter are predicted in different PWM methods- SVPWM, LLPWM proposed RPPWM.