SR 버퍼할당 메카니즘에 관한 연구

박성헌,김훈,박세환,최현호,박광채 조선대학교 에너지.자원신기술연구소 1997 에너지·자원신기술연구소 논문지 Vol.19 No.2

Since services in ATM networks are very various and the characteristic of traffic from services is very different from each one, shared buffer mechanism, that shares only one buffer, cannot satisfy QoS, requirement for traffics. Furthermore, it has more difficulty in controlling composite cells in buffer when large ATM switch is implemented. In this paper, we propose cell service scheduling of separated routing allocation mechanism that allocates respective, independent buffer to cells with same traffic characteristic according to priority. We analyzed its performance using computer simulation. Then, we obtained cell loss probability changing buffer size and weighted value, when cell service scheduling is done by unsymmetrical round-robin depending on weighted value that is allocated to respective buffer.

흰쥐 Kupffer 세포에 대한 Propofol의 작용

박세훈,지대림,성언기,김희선,송인환,박희영,김준수,이덕희,박대팔 대한마취과학회 2002 Korean Journal of Anesthesiology Vol.43 No.4

Background: Propofol has an antioxidant capacity and can be used for ischemia-reperfusion injury of the liver. However, the effects of propofol on the Kupffer cells have not been establisked. Methods: Kupffer cells were isolated and cultured from male Sprague-Dawley rats. The effects of propofol on the Kupffer cells were evaluated by a phagocytosis assay, TNF-α gene expression, and superoxide anion release after administering propofol in different concentrations on the cultured Kuprrer cells. Results: The latex bead phagocytosis by the Kupffer cells was suppressed when the Kupffer cells were exposed to propofol irrespective of concentrations. Higher propofol concentrations decreased the loss of Kupffer cells after latex bead phagocytosis. Propofol induced TNF-α mRNA expression in the Kupffer cells, but the mRNA expression level after 50㎍/ml of propofol decreased. The pattern of TNF-α mRNA expression induced by propofol was different to that induced by LPS: TNF-α mRNA was expressed continuously in the propofol-treated cells until 16 hours after exposure to propofol, whereas the level of TNF-α mRNA expression induced by LPS was evident after 2 hours and was not found thereafter. TNF-α production after propofol treatment was not higher than that of the control. Formazan presipitation did not show any qualitative differences between cells untreated or treated with propofol concentrations of 0.5, 5.0, and 50 ㎍/ml. Conclusions: These results showed that propofol might inhibit Kupffer cells. This suggests that propofol and be used for patients with ischemia-reperfusion injury of the liver. (Korean J Anesthesiol 2002; 43: 475~484)

TMS320F240을 이용한 PWM 인버터 유도전동기 구동 시스템의 전도노이즈 저감을 위한 스위칭 기법

朴奎炫,金利勳,元忠淵,金奎植,崔世琓,咸年根 성균관대학교 2003 학술회의지원논문목록집 Vol.2003 No.-

PWM 인버터에 의해 구동되는 유도전동기에 발생되는 고주파 커먼 모드 전압은 전도성 EMI, 전동기 접지전류, 베어링 전류 및 다른 원치 않는 결과의 주원인이 된다. 인버터 제어의 무효벡터 스위칭 상태는 나머지 유효벡터 스위칭 상태에 비교하여 큰 커먼 모드 전압을 일으킨다. 그러므로 이 논문은 커먼 모드 전압을 완화하는 스위칭기법을 다룬다. 즉 정현파 PWM기법을 기본으로 한 커먼 모드 전압 제거방법을 제안하였다. PWM 신호는 각각의 정현파 기준신호와 120˚위상차가 나는 3개의 캐리어 파형과 비교하여 발생된다. 시뮬레이션과 실험적결과는 제안된 PWM 기법에서 커먼 모드 전압이 종래의 PWM 기법보다 약 66% 더 저감됨을 보였다. High frequency common mode voltage produced by PWM inverter fed induction motor is a major cause of conducted EMI. creation motor ground currents, bearing currents and other hamful products. The zero switching states of inverter control invoke large in comparison with the non-zero switching state of inverter control. We proposed a common mode voltage reduction method based on sinusoidal PWM technique. PWM signal are generated by comparing respective sinusoidal reference signal with three triangular carrier wave displaced of 120˚. Simulation and experimental result show that common mode voltages in the propsed PWM technique are reduced by approximate 66% more than conventional PWM technique.

高精度의 DUAL-SLOPE 積分型 A/D 變換器 設計

박차훈,서희돈,최세곤 嶺南大學校 工業技術硏究所 1990 연구보고 Vol.18 No.1

In this paper, an effective method, which eliminates the error of the preamplifier, the integrator and the comparator, is proposed. An improved dual-slope integrating A/D converter, composed of the two-stage operational amplifier which is controlled by the control logic circuit switches and the variable ring counter, is for high accuracy. The results of computer simulation show that the conversion error is eliminated completely and the accuracy improved up to the level of the amplification of operational amplifier. These results satisfy the requirment of performance for the high accuracy dual-slope integrating A/D converter.

NRZ Random Bit 동기를 위한 Sampling Phase Detector

박세현,박세훈 安東大學校 工業技術硏究所 2000 공업기술연구논문집 Vol.7 No.1

본 논문에서는 NRZ 랜덤 비트 동기를 위한 새로운 Sampling Phase Detector를 제안한다. 제안하는 SPD는 국부 기준 신호의 주기와 입력 신호의 비트 구간의 위상 차의 평균값을 계산한다. 시뮬레이션과 실험 결과는 제안된 SPD가 NFZ 랜덤 신호의 Phase Detector로 유용하다는 것을 보여 준다. 제안된 SPD를 사용하여 NRZ랜덤 비트 동기 회로를 설계하고 구현하였다. This paper proposes a new type of Sampling Phase Detector (SPD) for NRZ random bit synchronization circuit. The proposed SPD calculates the mean value of phase difference between bit interval of input signal and period of local reference. Simulated and experimental results show that the proposed SPD is applicable to the phase detector for NRZ random signal. Finally the Random NRZ bit synchronization circuit, is designed and implemented by using SPD.

전기장 인가에 따른 DNA 신장에 관한 AFM 연구

박진영,한성웅,손세영,송성훈,김종민,Ohtani, Toshio,Muramatsu, Hiroshi,장상목 한국화학공학회 2002 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.40 No.1

본 연구에서는 마이카 표면상에서 전기장에 의한 극히 낮은 농도의 DNA 신장에 대한 효율적인 방법론을 제시하였다. 전기장에 의한 DNA 신장을 AFM형상으로 분석한 결과, DNA 농도범위가 약 57×10 exp(-3)ng/mL-57×10 exp(-6)ng/mL일 때 매우 잘 적용되며, 신장된 DNA는 두 전극 중앙에 존재하였다. 또한, 일반 마이카, Mg^2+ 처리된 마이카, 그리고 AP-마이카 표면들에 대한 신장 효율의 차를 기술하였다. 동일한 실험조건 하에서 AP-마이카의 표면이 가장 좋은 효율의 DNA 신장 결과를 나타내었다. An effective method of DNA stretching using electric field on mica surface was proposed for extremely low solution concentration of DNA. DNA stretching based on electric field was observed by AFM and well applied on the concentration range from 57×10 exp(-3)ng/mL to 57×10 exp(-6)ng/mL. Stretched DNA existed in the middle of two electrodes. The difference in stretching efficiency for the different surfaces of bare mica, Mg^2+ soaked mica and AP-mica was discussed. The best performance of stretching was found from the surface of AP-mica under the same experimental condition.

Terfenadine과 Ketoconazole 복용 후 발생된 Torsades de pointes 심실 빈맥증의 치험 1례

김세경,이기중,유승진,박일영,박승현,임근우,이원재,강동헌 대한응급의학회 1995 대한응급의학회지 Vol.6 No.1

Torsades de pointes is a form of polymorphic ventricular tachycardia that is associated with prolongation of the QT interval, characterized by QRS complexes of progressively changing amplitude and contour that seem to revolve around the isoelectric line. The most common cause of Torsades de pointes induced by antiarrhythmic agents, occupying in certain drugs or toxin, electrolyte disturbance, congenital QT prolongation syndrome. Cardiotoxicity terfenadine, in overdose a widely used, nonsedating antihistamine, has been reported. Case after administration of terfenadine and ketoconazole causing syncope and torsades de pointes have been reported in recommended dose. We report a case of QT prolongation with torsades de pointes after therapeutic administration of terfenadine, a long acting histamine H1 receptor antagonist, together with ketoconazole, an antifungal preparation. The patient is a 43-year-old female, who experienced palpitation, dizziness and syncopal episoders after coadministration of terfenadine and ketoconazole, for a fungal infection of the skin. The ECG showing typical episodes of torsades de pointes with QT prolongation. Magnesium sulfate was given, torsades de pointes did not recur. The patient was discharged with improved condition.

공간지각 능력수준에 따른 활성화 뇌 영역의 차이 : fMRI 연구 An fMRI study

손진훈,김연희,이경화,박세훈 한국뇌학회 2001 한국뇌학회지 Vol.1 No.2

본 연구는 공간지각 능력이 높거나 낮은 사람들이 공간지각 과제를 수행하는 동안 활성화되는 뇌 영역을 확인하기 위해 수행하였다. 428명의 대학생을 대상으로 집단심리실험을 수행하여, fMRI 연구를 위한 실험참여자로 30명의 오른손잡이 여대생을 선정하였다. fMRI 실험을 위한 패러다임은 block디자인으로, 한 block 내에 공간지각과제 세 문항이 포함되어 있는 네 block으로 구성되었다. fMRI imaging은 1.5T Siemens Vision Scanner로 수집되었으며, single-shot EPI 기법으로(TR/TE: 3840/40ms, flip angle: 90, FOV: 220, 64×64 matrix) 이미지를 스캔하였다. 자료분석은 SPM-99 소프트웨어를 사용하였다. 감산(subtraction)분석결과, 공간지각 능력이 우수한 집단은 양측 대상회(bilateral cingulate gyri)와 우측 상두정엽(right superior parietal lobe)에서 뇌 활성화가 더 많이 나타났고, 우측 시상(right thalamus)과 좌측 측-후두엽(left temporooccipital)은 공간지각능력이 떨어지는 집단에서 더 많이 활성화되었다. 이는 공간지각능력의 차이가 뇌의 활성화에 기인한다는 것을 나타낸다. The purpose of study was to identify brain areas that become activated while subjects performing visuospatial tasks(VST) with different performance levels. 428 college students were evaluated for VST, then 30 females were selected for fMRI study. Subjects were selected through psychometric test and were right-handed with no history of brain injury. The fMRI paradigm was designed to have 4 blocks of each task and each block has 3 items. Imaging was performed on a 1.5T Siemens Vision Scanner. Single-shot EPI fMRI scans(TR/TE 3840/40ms, flip angle 90, FOV 220, 64x64 matrix) were acquired. Imaging data were motion-corrected, coregistered, normalized, and then analyzed using SPM-99. There was greater activation in the bilateral cingulate gyri and the right superior parietal lobe for better VST performance group, whereas the right thalamus and left temporooccipital area for poor VST performance group.

PWM 인버터 시스템에서의 전도노이즈 저감을 위한 출력필터 설계에 관한 연구

金利勳,朴奎炫,元忠淵,金榮石,崔世琓 성균관대학교 2002 학술회의지원논문목록집 Vol.2002 No.-

본 논문에서는 PWM 인버터-유도전동기 구동시스템의 전도노이즈 저감을 위한 출력필터 설계에 관한 연구를 수행하였다. 전도 노이즈는 고전압 압력, 고용량 구동시스템, 그리고 긴 전동기 터미널 등의 경우에서 크게 문제가 된다. 고압력을 갖는 시스템에서는 높은 압력에 비례한 직류 링크 전압을 갖고 이에 따라 스위칭 시 dv/dt가 순간 최대 CM 접지전류를 발생시킨다. 그러므로 이에 대한 대책에 필요하다. 따라서 최근 산업 현장에서 많이 사용되고 있는 PWM 인버터를 설계 제작하여 유도전동기를 구동하고 이에 따라 발생되는 전도노이즈 성분을 감쇠 시킬 수 있는 출력필터를 설계하였고 제작 및 실험을 통하여 그 타당성을 입증하였다. In this paper, filtering techniques to reduce the adverse effects of motor leads on high-frequency PWM inverter fed AC motor drives are presented. The filter was designed to keep the motor terminal from the cable surge impedance to reduce overvoltage reflections, ringing, and the dv/dr, di/dt, at the motor terminals. Specially, the output filter is used to limit the rate of the inverter output voltage and reduce common mode noise to the motor. The performance of the output filter is evaluated through simulations and experiment on PWM inverter-fed AC motor drive. An experimental PWM drive system reduction of conducted EMI was implemented on an available TMS320C31 micoprocessor controd board. Finally, experimental result shows inverter output filter reduces more common mode voltage than low pass filter also reduce overvoltage and ringing at the motor terminal.

생체신호처리용 ASIC 칩 개발

배용욱,박차훈,서희돈,최세곤 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

The biotelemetry system transmits monitored physiological signal from multiple subjects to an electrical instrument at remote place where this information can be observed via electrical or optical link. In this paper, we developed an optical linked telemetry system which can transmit 6-channel physiological signals from 4 subjects, simultaneously. The proposed telemetry system is fabricated with Altera FPGA chip(EPM7128LC84-20) and 0.8μm CMOS n-well process technology. We designed a All-Digital PLL to synchronize with the external measurement system which consisted of a command signal transmitter and a telemetry signal demodulator. The operation characteristic of a All-Digital PLL is superior than an enforced synchronization oscillator which consisted of negative elements and a comparator. The required time to synchronize with a external measurement system at the maximum phase error is about 10.3ms. The novel external measurement system is implemented with Altera FPGA chip (EFM7096LC84-15).