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김건희,김효식,양순철,이상용,국명호,이선규,김윤중,홍권희 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-
This paper describes development of low cost precision machine that has combined the Build-in Motor with a vacuum chuck. This study mainly aims to find out a cutting condition for maintaining optimum surface condition and to examine cutting characteristics of the precision machine that is equipped by diamond bites. The cutting materials is Al alloy. Several experiments were carried out to find out the main factors that affect the surface roughness such as principal axis RPM(rotation per minute), feeding speed, and cutting depth. As a result, we obtain The optimum cutting condition of the developed precision machine.
A Novel Dead-Time Compensation Method using Disturbance Observer
Youn, Myung-Joong,Moon, Hyung-Tae,Kim, Hyun-Soo The Korean Institute of Power Electronics 2002 JOURNAL OF POWER ELECTRONICS Vol.2 No.1
A new on-line dead-time compensation method for a permanent magnet (PM) synchronous motor drive is proposed. Using a simple disturbance observer without any additional circuit and off-line experimental measurement, disturbance voltages in the synchronous reference dq frame caused by the dead time and non-ideal switching characteristics of power devices are estimated in an on-line manner and fed to voltage references in order to compensate the dead-time effects. The proposed method is applied to a PM synchronous motor drive system and implemented by using software of a digital signal processor (DSP) TMS320C31. Simulations and experiments are carried out for this system and the results well demonstrate the effectiveness of the proposed method.
( Myung Jin Jee ),( Soon Man Yoon ),( Eui Joong Kim ),( Hyun Jung Choi ),( Jong Won Kim ),( Ro Hyun Sung ),( Joung Ho Han ),( Hee Bok Chae ),( Seon Mee Park ),( Sei Jin Youn* ) The Editorial Office of Gut and Liver 2013 Gut and Liver Vol.7 No.6
Familial juvenile polyposis (FJP) is a rare autosomal dominant hereditary disorder that is characterized by the development of multiple distinct juvenile polyps in the gastrointestinal tract and an increased risk of cancer. Recently, germline mutations, including mutations in the SMAD4, BMPR1A, PTEN and, possibly, ENG genes, have been found in patients with juvenile polyps. We herein report a family with juvenile polyposis syndrome (JPS) with a novel germline mutation in the SMAD4 gene. A 21-year-old man presented with rectal bleeding and was found to have multiple polyps in his stom-ach, small bowel, and colon. His mother had a history of gastrectomy for multiple gastric polyps with anemia and a history of colectomy for colon cancer. A review of the histol-ogy of the polyps revealed juvenile polyps in both patients. Subsequently, mutation screening in DNA samples from the patients revealed a germline mutation in the SMAD4 gene. The pair had a novel mutation in exon 10 (stop codon at tyrosine 413). To our knowledge, this mutation has not been previously described. Careful family history collection and genetic screening in JPS patients are needed to identify FJP, and regular surveillance is recommended. (Gut Liver 2013;7:747-751)
Synchronous PI Decoupling Control Scheme for DVR against a Voltage Sag in the Power System
Myung-Bok Kim,Seung-Hoon Lee,Gun-Woo Moon,Myung-Joong Youn 전력전자학회 2004 JOURNAL OF POWER ELECTRONICS Vol.4 No.3
This paper proposes a new control strategy for the dynamic voltage restorer (DVR). It is based on a synchronous PI decoupling control strategy which features fast response time and low steady state error. Therefore, the proposed control strategy produces faster action time against voltage sag and guarantees more than enough compensation for reduced supply voltage. Experimental results, implemented with the TMS320C3x DSP control unit, are shown to validate the effectiveness of the proposed control strategy.
Prognostic factors for gallbladder cancer in the laparoscopy era
Hak Youn Lee,Young Hoon Kim,Ghap Joong Jung,Young Hoon Roh,Si Young Park,Nam Uk Kang,Soon Hwa Yoon,Jin Han Cho,Myung Hwan Roh,Sang Young Han,Sung Wook Lee,Yang Hyun Baek,Jin Sook Jeong 대한외과학회 2012 Annals of Surgical Treatment and Research(ASRT) Vol.83 No.4
Purpose: Hepatobiliary surgery has changed dramatically in recent decades with the advent of laparoscopic techniques. The aim of this retrospective study was to compare survival rates according to stages, adjusting for important prognostic factors. Methods: A retrospective study of a 17-year period from January 1994 to April 2011 was carried out. The cases studied were divided into two time period cohorts, those treated in the first 9-years (n = 109) and those treated in the last 7-years (n = 109). Results: An operation with curative intent was performed on 218 patients. The 5-year survival rates according to the depth of invasion were 86% (T1), 56% (T2), 45% (T3), and 5% (T4). The number of cases of incidental gallbladder cancer found during 3,919 laparoscopic cholecystectomies was 96 (2.4%). Incidental gallbladder cancer revealed a better survival rate (P = 0.003). Iatrogenic bile spillage was found in 20 perforations of the gallbladder during laparoscopic cholecystectomies, 16 preoperative percutaneous transhepatic gallbladder drainages and 16 percutaneous transhepatic biliary drainages; only percutaneous transhepatic biliary drainage patients showed a significantly lower survival rate than patients without iatrogenic bile spillage (P < 0.034). Chemoradiation appeared to improve overall survival (P < 0.001). Multivariate analysis also revealed that time period, type of surgery, surgical margin, lymphovascular invasion, lymph node involvement, and chemoradiation therapy had significant effects. Conclusion: This study found that the prognosis of gallbladder cancer is still determined by the stage at presentation due to the aggressive biology of this tumor. Early diagnosis, radical resection and appropriate adjuvant therapy can increase overall survival.
Wonkeun Youn,고하윤,Hyungsik Choi,Inho Choi,Joong-Hwan Baek,Hyun Myung 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.2
This paper proposes a novel complete navigation system for autonomous flight of small unmanned aerial vehicles (UAVs) in GPS-denied environments. The hardware platform used to test the proposed algorithm is a small, custom-built UAV platform equipped with an onboard computer, RGB-D camera, 2D light detection and ranging (LiDAR), and altimeter. The error-state Kalman filter (ESKF) based on the dynamic model for low-cost IMU-driven systems is proposed, and visual odometry from the RGB-D camera and height measurement from the altimeter are fed into the measurement update process of the ESKF. The pose output of the ESKF is then integrated into the open-source simultaneous location and mapping (SLAM) algorithm for pose-graph optimization and loop closing. In addition, the computationally efficient collision-free path planning algorithm is proposed and verified through simulations. The software modules run onboard in real time with limited onboard computational capability. The indoor flight experiment demonstrates that the proposed system for small UAVs with low-cost devices can navigate without collision in fully autonomous missions while establishing accurate surrounding maps.