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( Jehyun Yoo ),( Sangmin Kim ),( Hojung Jung ),( Jihyo Hwang ) 대한고관절학회 2019 Hip and Pelvis Vol.31 No.2
Purpose: This study was performed to assess the radiologic and clinical results of U-blade Gamma3 nail use for the treatment of trochanteric fractures. Materials and Methods: Between September 2015 and May 2018, all patients aged 65 years and older who underwent surgery with U-blade Gamma3 nails were analyzed. A total of 129 patients were selected based on having at least six months of follow-up. Image evaluations included bone quality (T-score), fracture classification on plain radiograph (AO/OTA), computed tomography configuration, union period, position of lag screw, anatomical reduction, tip apex distance (TAD), sliding extent of lag screw, change of neck shaft angle, and complications leading to reoperations were analyzed. Functional outcome were assessed using the Koval grade (ambulatory ability) at the final follow-up. Results: The mean time to union was 19.7 (range, 6-36) weeks. The screw position was centric (93 cases; 72.1%) and anatomical reduction was achieved in 74 cases (57.4%). The mean TAD was 20.3 (range, 12.3-38.1) mm. The mean sliding length of the lag screws was 3.8 (range, 0.1-12.6) mm. The mean change of neck shaft angle was 3.4˚ (range, 0-12.8˚ ). Reoperations were required in two cases (1.6%) due to the cutting out of the lag screw (n=1) and metal failure with U-blade bending (n=1). Finally, Koval grades for 49.8% of patients reached preoperative status. Conclusion: Overall, use of the U-blade Gamma3 nail led to favorable clinical results, suggesting that this system may be a good option for the treatment of trochanteric fractures.
Distributed Control For Multi-target Surveillance Using Limit Cycle
Jehyun Yoo,Jaemann Park,Hyoun Jin Kim 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10
In this paper, we propose a control law that makes multiple non-holonomic vehicles converge to a limit cycle with the same relative phase angle. All the agents use information on only their neighbors with which they can communicate. An adjacency matrix is used to represent the connectivity among the agents. With the phase portrait of the limit cycle and the heading angles of the vehicles, we derive the control law to make the vehicles move toward the limit cycle, and using information of neighbor’s we derived control input to make vehicles have the same relative phase angle. The potential field method is used for collision avoidance. The effectiveness of the proposed control law is shown using computer simulations.
Elastic Band Method를 사용한 충돌회피 경로 생성
유제현(Jehyun Yoo),황준연(Junyeon Hwang) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
본 연구는 Elastic Band Method를 사용한 차량의 충돌회피 경로 생성에 대해 다룬다. 충돌 회피에 관한 연구는 Voronoi Diagram, A*, D*, MILP(Mixed Integer Linear Programming) 등의 Global Path Planning Algorithm과 Potential Field Method, Virtual Hill Method등의 Local Path Planning Algorithm이 활발하게 진행되고 있으나, 실제 차량에 적용하기에는 계산 량이 많고 경로생성에 필요한 환경 정보 양이 많은 등의 한계가 있다. 본 연구에서는 이러한 단점을 보완하고자 Elastic Band Method 를 사용하여 충돌 회피 경로를 생성하였다. 한편 생성한 충돌회피 경로의 검증을 위하여 비선형 최적화 기법 중 하나인 MPC(Model Predictive Control)을 적용한 경로와 계산시간 등을 비교하였다.