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누설변압기가 부착된 전원 불평형 3상 전압형 PWM 컨버터 운전법
전지용(Ji yong Chun),김영춘(Young Chun Kim),조유환(Yu Hwan Cho),이근홍(Keun Hong Lee) 전력전자학회 2005 전력전자학술대회 논문집 Vol.- No.-
In this paper, the control algorithm of DC source device for inverter starting is proposed and the control method for compensating unbalance system source on operating time in the voltage type PWM converter with driving and regenerative faculty is suggested. The maintaining way of balancing condition for converter of AC source is used the compensating unbalanced status by current control loop. Because it is possible that the unbalanced System control is used to leakage transformer not equaled reactance by each phase in rectifier system, the proposed H/W and control algorithm of rectifier system is contributed to minimize of device and rising efficiency.
경골 고평부 골절에서 자기 공명 영상을 이용한 골절 행태 및 연부조직 손상의 평가
전지용 ( Ji Yong Chun ),박희곤 ( Hee Gon Park ),황성수 ( Sung Su Hwang ) 대한골절학회 2007 대한골절학회지 Vol.20 No.4
목적: 경골 고평부 골절에서 단순 방사선 사진과 MRI에서의 골절 형태에 대한 정보를 비교하여 골절 형태와 동반된 연부조직 손상을 평가하여, MRI의 유용성을 알아보고자 하였다. 대상 및 방법: 경골 고평부 골절로 MRI를 시행하였던 68예를 대상으로 단순 방사선 사진과 MRI에서 Schatzker 골절형, 관절면의 함몰, 골절편의 전위를 비교하였고, MRI에서 슬관절부의 연부조직 손상을 조사하였다. 결과: 단순 방사선 사진의 Schatzker 골절형이 MRI에서 변경된 경우가 7예 있었으며 관절면의 함몰은 단순 방사선 사진에서 평균 2.93 ㎜, MRI에서 평균 4.28 ㎜로 1.35 ㎜ 증가되어 통계학적으로 의미가 있었다 (p<0.05). 골절편의 전위는 유의한 차이가 없었다 (p=0.168). MRI에서 인대 및 반월상 연골 손상은 58예 (85.3%)에서 발견되었다. 결론: 경골 고평부 골절에서 MRI는 추가의 골절선이나 함몰을 발견할 수 있어 골절 분류가 바뀔 수 있고, 관절면의 함몰과 연부조직 손상에 대한 정보를 제시하여 수술적 치료 계획을 세우는 데 많은 도움이 된다. 경골 고평부 골절 시 수술 전에 MRI를 시행하는 것이 보다 나은 골절 치료와 연부 조직의 치료를 위하여 반드시 필요하다고 생각한다. Purpose: To compare information about fracture type in MRI with simple radiograph in tibial plateau fractures and evaluate tibial plateau fractures type and accompanying soft tissue injury, and evaluate usefulness of MRI in tibial plateau fractures. Materials and Methods: Compared MRI with simple radiograph about Schatzker classification, depression of articular surface and displacement of bone fragment from the 68 examples who checked MRI and we evaluated soft tissue injury around knee joint. Results: There were 7 examples of Schatzker type change after MRI check. Average depression of articular surface in simple radiograph was 2.93 ㎜ and 4.28 ㎜ in MRI. It in creased by 1.35 ㎜ and it was meaningful statistically (p<0.05). There was no significant difference between MRI and simple radiograph of displaced bone fragment (p=0.168). There were 58 (85.3%) cases of soft tissue injury in MRI. Conclusion: MRI can find additional fracture line or articular depression that can`t be found in simple radiograph and gives more information about articular depression and soft tissue that is useful in surgical plans. I think preoperative MRI is necessary to better treatment of fracture & treatment of periarticular soft tissue injury in tibial plateau fracture.
정춘병(Chun-Byung Chung),전지용(Ji-Yong Chun),전기영(Kee-Young Jeon),한경희(Kyung-Hee Han) 한국조명·전기설비학회 2008 한국조명·전기설비학회 학술대회논문집 Vol.2008 No.5월
In this paper, The author present a load current feed-forward compensator by method that improve voltage controller of Step-down Chopper to get stable output voltage to sudden change of load current. To confirm the characteristicsof a presented load current feed-forward compensator compared each transfer function of whole system that load current feed-forward compensator is added with transfer function of whole system that existent voltage controller is included using Mason gains formula in Root locus and Bode diagram. As a result the pole of system is improved, extreme point of the wave and system improves, and size of peak value and phase margin of break frequency in resonance frequency confirmed that is good. Therefore, presented control technique could confirm that reduce influence by perturbation and improves stationary state and dynamic characteristics in output of Step-down Chopper.
이성철,정홍근,전지용,유제욱,Lee, Sung-Chul,Jung, Hong-Geun,Chun, Ji-Yong,Yu, Je-Wook 대한족부족관절학회 2005 대한족부족관절학회지 Vol.9 No.1
Purpose: To analyze the overall clinical outcome, overall assessment, and patient's satisfaction rate of subtalar arthrodesis using the cannulated compression screw. Materials and Methods: This study is based on 17 patients, 17 feet who underwent subtalar arthrodesis using the cannulated compression screw from March, 1997 to March, 2004 with at least 1 year follow-up. The average follow-up period was 33.0 months (12 to 72 months). Functional results were assessed using the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot (AOFAS) score, and Visual Analysis Scale (VAS) pain score, patients' returning to previous occupation and patients' satisfaction rate were also evaluated. Results: The mean AOFAS scores at final follow-up were 80.4 points (range $66{\sim}92$). The satisfactory rates were as follow. Thirteen patients (76.4%) were at least satisfied with surgical result at final follow-up. Patients' VAS pain score was average 2.8 points ($1{\sim}6$). Fourteen (82.3%) patients returned to previous job at mean postoperative period of 11.3 months (range 3-18 months). Patients' work efficiency after returning to previous occupation was 68.7% (range $33{\sim}100%$). There were 9 complications which were 3 cases of sural nerve injury, 1 case of valgus malunion, and 5 cases of the hindfoot residual pain. Conclusion: We obtained the satisfactory functional results with relatively high patient satisfaction rate of 76%. So we conclude that subtalar arthrodesis using the cannulated compression screw is a reliable method for addressing the painful end-stage subtalar osteoarthritis and unreconstructible comminuted calcaneal fractures. However we also found out that average 11 months were necessary for patients to return to their job.
도시철도차량의 성능 향상을 위한 점착특성 기법에 관한 연구
김영춘(Kim, Young-Choon),전지용(Chun Ji-Yong) 한국산학기술학회 2006 한국산학기술학회논문지 Vol.7 No.2
전기철도차량의 성능특성을 향상시키기 위한 효과적인 방법중의 하나는 바퀴와 레일사이의 점착성능을 향상 시키는 것이다. 점착특성을 연구하기 위해서 실제 차량을 등자 모델링한 점착시스템을 제작하였다. 이 시스템은 다양한 점착 파라미터를 변화시켜 바퀴와 레일사이의 점착력을 바꿀 수 있도록 제작되었다. 이 논문은 공전속도를 제어하는 기능을 추가하여 점착성능을 향상시키는 연구이다. It is one of the most effective methods for improving the performance of electric railway vehicles to make better the wheel-rail adhesion characteristics. To study adhesion characteristic is to develop the equivalent reduction machine to experiment on the adhesion system. The experiment system makes it possible to change the wheel-rail adhesion force with various adhesion parameters, and therewith to test the adhesion control system with the reduction machine in a laboratory. In this paper, for improving adhesion performance shows actually control methods.