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2상 SRPP-PWM 기법을 사용한 유도모터 속도제어 시스템
위석오(Seog-Oh Wi),김정근(Jung-Kun Kim),임영철(Young-Cheol Lim),정영국(Young-Gook Jung) 전력전자학회 2002 전력전자학술대회 논문집 Vol.- No.-
In this paper, 2 phase modulated SRPP-PWM<br/> (Separately Random Pulse Position PWM) is proposed. This PWM technique is based on the 2 phase modulated SVPWM(Space Vector Pulse width Modulation). In according to the theory of SVPWM, 2 phase modulated SVPWM uses two pulses, not three pulses as in 3 phase modulated SVPWM. In the proposed SRPP- PWM scheme, each of two phase pulses is located randomly in each switching interval. The experimental results show that the voltage and switching noise harmonics are spread to a wide band area Also, the performance of the proposed 2 phase modulated SRPP- PWM and the conventional SVPWM are compared to each other. In result, the speed response is nearly similar to each other from the viewpoint of the v/f constant control
2상 및 3상 변조된 각상별 랜덤 펄스위치 펄스폭 변조기법의 성능비교
위석오(Seog-Oh Wi),임영철(Yung-Cheol Lim),정영국(Young-Gook Jung),나석환(Seok-Hwan Na) 전력전자학회 2002 전력전자학술대회 논문집 Vol.- No.-
In this paper, a comparative study on the performance of two-phase and three-phase randonuzed pulse position PWM scheme for mitigation of audible switching acoustic noise in motor drives is done in the randomized pulse position PWM, each of two-phase or three-phase PWM pulses is located randomly in each switching interval. Simulation and experimental efforts were executed to investigate the spread effects of power spectra of inverter output voltage, waveforms of ripple current and audible switching acoustic noise.
한석태(Seog-Tae Han),강지만(Jinman Kang),이정원(Jeong-Won Lee),제도흥(Do-Hyung Je),정문희(Moon-Hee Jung),김수연(Soo-Yeon Kim),위석오(Seog-Oh Wi) 한국전자파학회 2010 한국전자파학회논문지 Vol.21 No.11
본 논문에서는 밀리미터파 수신 시스템의 준광학계 회로에서 발생되는 3가지 빔 결합 손실에 대하여 가우시언 빔 전송 이론을 기반으로 심도 있게 검토하였다. 첫째, 준광학 시스템에 의하여 형성된 각각의 빔 허리와 그들의 위치가 서로 일치되지 않았을 때 발생되는 빔 결합 손실에 대하여 분석하였다. 빔 허리의 크기를 3 이상으로 설계하면 빔 광축 방향에 대한 빔 허리 크기와 그 위치의 불일치에 의한 빔 결합 손실을 최소화 시킬수 있다. 둘째, 준광학 회로에서 서로 다른 두 빔 축의 기울어짐과 각도상의 비정렬에 의한 빔 결합 손실을 해석하였다. 기울기 각도와 정렬에 의한 빔 결합 손실을 고려할 때 빔 허리의 크기가 작을수록 유리함을 알 수 있다. 마지막으로 광축 방향에 대하여 측면 방향으로 하나의 광축이 치우쳐 있는 경우의 결합 손실을 검토하였다. 치우침을 감안한 설계 빔의 반경은 최소한 3 이상이 되도록 설계되어야 한다. In this paper, three kinds of beam coupling losses which occur in a quasi-optics circuit for millimeter wave receiver system have been intensively investigated. First, the beam coupling losses which are caused by mismatch of beam waists radii and their positions between those of one and the other have been evaluated. It shows that beam coupling losses due to mismatch of beam waists radii and their positions between two quasi-optics circuits can be minimized if beam waist radius is chosen as larger than 3 times the operation wavelength. Second, the beam coupling losses have been studied when the axis of propagation of one beam is tilted with respect to that of the other beam. It is noted that smaller beam waist radius results in greater tolerance to tilts and angular misalignments. Third, the beam coupling cases in which two beams are offset if their axes of propagation are parallel but one is displaced relative to the other have been investigated. It is confirmed that beam waists radii with larger than 3 times operation wavelength are less sensitive to lateral offsets.
진행성 비소세포 폐암에 대한 Mitomycin C, Vinblastine 및 Cisplatin(MVP) 3제 복합 화학요법의 치료 효과
김상위 ( Kim Sang Wi ),안명주 ( An Myeong Ju ),서철원 ( Seo Cheol Won ),이규형 ( Lee Gyu Hyeong ),이정신 ( Lee Jeong Sin ),고윤석 ( Go Yun Seog ),김우성 ( Kim U Seong ),김원동 ( Kim Won Dong ),김상희 ( Kim Sang Hui ) 대한내과학회 1993 대한내과학회지 Vol.44 No.2
Background : Advanced non-small cell lung cancer (NSCLC) is still a lethal disease and one of the most important causes of cancer-related death. Role of systemic chemotherapy seems to be pallicative and showed objective response of 30-40%. We treated 33 patients with advanced NSCLC with combination therapy of mitomycin C, vinblastine, and cisplatin (MVP) to evaluate the clinical activity and side effect of this combination. Mothods : Cisplatin was infused intravenously on day l at the dose of 60mg/㎡ with pre-and post-hydration and mitomycin C 6mg/㎡ (maximum 10mg) and vinblastine 6mg/㎡ (maximum 8mg) were given intravenously on day 2. The treatiment was repeated every 3-4 weeks, and at least 2 cycles of chemotherapy were administered. Results : Nine patients (27%) had partial responses and no one had complete response. Median response duration was 16 weeks, reange (4+to 28 weeks). The toxicity included mild and transient nausea/vomiting, mild to moderate leukopenia, and mild peripheral neuropathy, All of them were well tolerated and recovered fully before the next cycle of chemotherapy. Conelusion : MVP combination chemotherapy is moderately active against advanced NSCLC and relatively well tolerated.
A Pseudorandom Carrier Modulation Scheme
Young-Cheol Lim,Seog-Oh Wi,Jong-Nam Kim,Young-Gook Jung IEEE 2010 IEEE transactions on power electronics Vol.25 No.4
<P>This paper describes a pseudorandom carrier modulation scheme and its harmonic spectra spread effect. The pseudorandom carrier of the proposed scheme are produced through the random synthesis of the two triangular carriers, each of the same fixed frequency, but of opposite phase. The random selection of the two triangular carriers is decided by ``0'' or ``1'' states of the pseudorandom binary sequence (PRBS) random bits. Multiplexer which are used as random selector of the PRBS random bits, produces the resultant pseudorandom frequency carrier waveform. In order to verify the validity of the proposed method, the simulations and experiments were conducted and tested with a single-phase low-power H-bridge multilevel inverter. An EXAR XR2207 is used as a triangular carrier generator with fixed frequency, also an XR2206 is used for generation of single-phase sinusoidal wave. The PRBS random bits generator is implemented, using a shift register and an EXCLUSIVE OR gate. The experimental results show that the harmonics spectra of voltage and current are dispersed over a wide-band area by using the proposed scheme.</P>
새로운 3상 랜덤 펄스 위치 PWM기법에 의한 EPLD기반의 모터 속도제어 시스템
김회근(Hoe-Geun Kim),위석오(Seog-Oh Wi),임영철(Young-Cheol Lim),정영국(Young-Gook Jung),나석환(Seok-Hwan Na) 전력전자학회 2002 전력전자학술대회 논문집 Vol.- No.-
In tins paper, EPLD(Erasable Programmable Logic Device) based induction motor drives with a SRP-PWM(Separatley Randomized Pulse Position PWM) is proposed in the proposed RPWM (Random PWM), 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. To verify the validity of the proposed RPWM, the experimental study was tried Along With the randomization of PWM pulses, the space vector modulation is also executed in the TMS32OC31 DSP(Digital Signal Processor) The experimental results show that the voltage and switching noise harmonics are spread to a Wide band area Also, the performance of the proposed SRP- PWM and the conventional SVM-PWM are nearly the same from the viewpoint of the v/f constant control
이병서 ( Lee Byeong Seo ),위태석 ( Wi Tae Seog ) 한국식품유통학회 2003 食品流通硏究 Vol.20 No.2
This study discussed the large scale retailers’ preference and perception to the trading behavior and quality characterstics of farm products. Results are as follows : (1) The differentiation and quality uniformity are important factors in brand management. (2)Lager scale retailers want to deal with more environment-friendly products, but the procurement stability, quality trustworthiness, and crop assortment are still in the process of improvement. (3) It is important to keep uniformity of both external and internal quality factors in grading. (4) Large scale retailers prefer the products of small0sized boxes, but farmers have to consider the price premium and cost increase. (5) Farmer group feel that they have relatively weak bargaining power as compared with large scale retailer?. (6) It is important to reduce the information asymmetrictiy. Farmers group need to inform the large scale retailers of farm level information. This may reduce large scale retailers? searching cost of farm products.