• Journal of Chest Surgery
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• 제56권4호
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• pp.229-237
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• 2023

Background: We aimed to demonstrate the advances we have achieved in pectus excavatum surgery over the last 10 years, with a particular focus on the refinement of pectus bar stabilization techniques and devices. Methods: In total, 1,526 patients who underwent minimally invasive repair of pectus excavatum surgery from 2013 to 2022 were enrolled and analyzed. We have pursued a new paradigm of crane-powered remodeling of the entire chest wall. The method of bar stabilization has changed from claw fixators to hinge plates and, finally, to bridge plate connections. We also evaluated the effectiveness of the hinge plate (group H) and the bridge plate (group B). Results: The bar displacement rates were 0.1% (n=2) for the claw fixator, 0% for the hinge plate (n=0), and 0% for the bridge plate (n=0). We stopped using the claw fixator in 2022 and the hinge plate in 2019. Since 2022, when we shifted to a multiple-bar technique for all patients, the bridge plate has replaced both the claw fixator and the hinge plate. No bar displacement occurred in either group. Group H had more pleural effusion, wound problems (p<0.05), and longer stays (5.5 vs. 6.2 days, p=0.034) than group B. Conclusion: We have made significant progress in pectus repair surgery over the last decade, particularly in stabilizing the pectus bar and reducing perioperative complications. Our current strategy is the multiple-bar approach with bridge stabilization. Since the bridge-only technique resulted in no bar displacement, we could eliminate the invasive claw fixator or hinge plate.

• 대한치과보철학회지
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• 제53권1호
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• pp.66-73
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• 2015

완전, 혹은 부분 무치악 환자의 가철성 보철물 수복치료에서 치아 상실에 따른 치조골 감소와 별형은 의치 사용에 어려움을 준다. 이런 문제를 극복하기 위해 임플란트를 이용하여 가철성 보철물에 지지, 유지, 및 안정을 제공할 수 있다. 임플란트를 이용한 피개의치에 사용되는 어태치먼트는 여러 종류가 있는데, 환자의 여러 조건을 고려하여 어태치먼트를 선택해야 한다. 그 중 milled bar의 경우 임플란트 간 거리가 좁아서 기성 bar를 사용할 수 없는 경우, 또는 기성 bar보다 상부 구조물의 확고한 안정성과 지지를 얻고자 할 때 선택 된다. Milled bar는 cross arch stabilization을 이룰 수 있고, 저작 시 의치의 움직임이 없어 환자에게 편안함을 제공하지만, 숙련된 기공과정을 요한다. 그러나 최근 CAD/CAM의 발전을 통해 milled bar의 제작이 간결해지고 적합성을 증진시킬 수 있었다. 본 증례는 8개의 임플란트가 식립된 하악 완전 무치악의 알츠하이머 환자로 milled bar와 magnet을 이용한 피개의치를 제작하였다. 전신병력이 양호해진 기간 동안 빠른 치료종결이 필요했기 때문에, 통법의 기공 작업을 CAD를 통해 시뮬레이션하여 복잡한 기공과정을 좀더 단순하게 하였고 이로써 치료 기간을 줄일 수 있었다. 이상과 같이 milled bar를 이용한 임플란트 지지 피개의치를 제작하는 과정 중 CAD/CAM system을 적절히 사용하여 심미적, 기능적으로 만족할 만한 결과를 얻었기에 보고하고자 한다.

• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.320-327
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• 2005

A new mechanism for hyper redundant manipulator (HRM) is presented, which comprises of serially assembled compound three-bar linkages (CTL). The CTL mechanism has some unique properties. This paper presents the forward and inverse kinematics of this mechanism and shows the simulation of the HRM havig 9 CTL units. The recursive algorithm of the inverse kinematics that the author originally developed is employed. It is fast and stable ; moreover, it enables us to obtain a solution in which the end-point of the HRM is controlled by a portion of joints. It also presents the method of the dynamical analysis. There exist kinematical constraints in the proposed closed linkage mechanism. In the dynamic analysis constraints are sufficiently sustained by the constraint stabilization method that the author developed. The mechanical structure of the HRM having some CTL units that is under construction is shown.

• Journal of Chest Surgery
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• 제56권4호
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• pp.238-239
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• 2023

• 대한심미치과학회지
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• 제8권1호
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• pp.46-59
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• 1999

A fixed bridge is preferred as a prosthetic option supported by oral implants. However, it is very difficult to re tore edentulous maxilla with fixed prosthesis in cases with improper position and angulation of fixtures, abnormal jaw relation, and need for proper lip support. Six Br${\aa}$nemark implants were installed in edentulous maxilla opposing mandible with natural dentition. A removable hybrid prosthesis attached to a bar milled by 6 degrees was therefore designed to overcome such disadvantages of fixed prosthesis. Lateral stabilization of removable prosthesis was obtained by framework closely fitting the milled bar. Support for the prosthesis was ensured by three elevated areas on the bar. Two precision attachments(CEKA REVAX) provided appropriate direct and indirect retention without influencing support. A clinical and laboratory procedure was presented.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집(한일합동학술편); 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.729-733
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• 1987

Stability of Co Semigroups perturbed via the steady state Riccati equation (SSRE) is studied. We consider an infinite dimensional system : .chi. over dot = A.chi. + Bu, in, (A), domain of A, where A is the infinitesimal generator of a Co semigroup [T(t), t.geq.0] in H. If the original Co semigroup [T(t), t.geq.0] has a lower bound : vertical bar T(t).chi. vertical bar .geq. k vertical bar .chi. vertical bar, for all .chi. in H. t.geq. 0 and k>0, then the perturbed Co semigroup via the SSRE, where the feedback operator B is compact, cannot be exponentially stable. Physical interpretation of this result is as follows : in real applications, a finite number of actuators are available, therefore the operator B is compact. When the original system is inherently unstable, that is, has an infinite number of unstable modes, the perturbed system via the SSRE cannot be stable with a uniform decay rate.

• 한국환경보건학회지
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• 제31권1호
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• pp.15-22
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• 2005

This study was conducted to evaluate air injection mode on stabilization of solid waste in lysimeter. For three lysimeters, one was maintained under anaerobic condition as control, and air was injected into two lysimeters in continuous mode (atmospheric pressure) and intermittent mode (high pressure of 2 bar). Distilled water was sprayed over solid waste in 1.4 l/$m^3$(solid waste)/day, supposing rainfall intensity of 1,200 mm/yr and 30% infiltration. Oxygen in landfill gas was not detected in control lysimeter during operational days. After 30 day-aeration, oxygen concentrations of continuous and intermittent modes were maintained in 14% and 6%, respectively. $COD_{Cr}$ removal efficiencies of continuous and intermittent modes were about 70% and 50%, and BOD5 removal efficiencies were about 80% and 20%, respectively. In view of oxygen supply, and $COD_{Cr}$ and $BOD_5$ removal, continuous air injection mode of atmospheric pressure was more effective than intermittent mode of 2 bar. Settling degree of solid waste in case of two air injection modes was 3 times higher than that of anaerobic condition as control. Considering the above results, it was thought that air injection (especially continuous atmospheric pressure) could improve degradation of solid waste and induce preliminary stabilization in landfill site.

• 한국운동역학회지
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• 제32권4호
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• pp.128-133
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• 2022

Objective: This study was executed to compare and analyze shoulder muscle activation while using an inelastic bar and elastic bar during overhead press exercise. The stability and coordination of shoulder joints will be investigated by measuring and analyzing the EMG of the upper and lower arm muscles. Method: A total of 20 university male students were recruited by dividing into 2 groups; 10 elastic bar participants (age: 20.17 ± 0.41 yrs, height: 174.31 ± 3.34 cm, weight: 74.68 ± 5.65 kg) and 10 inelastic bar participants (age: 20.09 ± 0.23 yrs, height: 173.53 ± 4.11 cm, weight: 75.32 ± 3.31 kg) participated in this study. Results: The EMG analysis results of the four muscles measured in this study showed that there was no difference between the left and right muscles between the groups in Upper Trapezius muscle. In Deltoid, Infraspinatus, and Rectus Abdominis muscles, the elastic bar group was significantly higher than the inelastic bar group between groups, and there was no difference between left and right. Conclusion: Among the four muscles measured in this study, there was no difference between left and right in Deltoid, Infraspinatus, and Rectus Abdominis, but the elastic bar showed significantly higher muscle activity than the inelastic bar. Therefore, it was found that the elastic bar increases muscle activation during exercise than the inelastic bar, and in particular, it further increases muscle activation of the arms and torso, and exercise using the elastic bar can increase neuromuscular stabilization.

• 국제물리치료학회지
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• 제11권1호
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• pp.1975-1980
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• 2020

Background: It has been argued that changes in muscle activity in the upper trapezius and serratus anterior may or may not cause shoulder joint pain and dysfunction. Objective: To investigate the effects of active vibration exercise on muscle activity regarding scapular stabilization using a flexi-bar. Design: A randomized controlled trial. Methods: A total of 24 subjects were randomly assigned to a flexi-bar group with active vibration and general stick group with non-active vibration. Both groups performed the same four action programs for 6 weeks, three times a week for 30 minutes at a time. The upper trapezius muscle, middle trapezius muscle, lower trapezius muscle and serratus anterior muscle of the dominant side was measured by electromyography before and after the 6 weeks of exercise. The independent t-test and paired t-test were used to analyze data. Results: There was a significant difference between groups in upper trapezius muscle and serratus anterior muscle activity after exercise (P<.05). Also, there was a significant difference in upper trapezius muscle and serratus anterior muscle activity before and after exercise in the flexi-bar group (P<.05). Conclusion: This study demonstrates that active vibration exercise using a flexi-Bar contribute to reduce the activity of the upper trapezius muscle and promote the activity of the serratus anterior muscle.

• 대한기계학회논문집A
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• 제30권8호
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• pp.897-905
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• 2006

This study considers an experimental design of disturbance compensation control to improve stabilization performance of main battle tanks. An adaptive non-parametric design technique based on the Filtered-x Least Mean Square(FXLMS) algorithm is applied in the consideration of model uncertainties. The optimal compensator is designed by two-step design procedures: determination of frequency response function of the disturbance compensator which can cancel the disturbance of series of single harmonics by using the FXLMS algorithm and determination of the compensator polynomial which can fit the frequency response function obtained in the first step optimally by using a curve fitting technique. The disturbance compensator is applied to a simple experimental gun-torsion bar-motor system which simulates gun driving servo-system. Along with experimental results, the feasibility of the proposed technique is illustrated. Experimental results demonstrate that the proposed control reduces the standard deviation of stabilization error to 47.6% that by feedback control alone. The directional properties of the FXLMS Algorithm such as the direction of convergence and its convergence speed are also verified experimentally.