• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.871-873
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• 2001

본 논문에서는 전기 단층 촬영 기법과 같이 많은 양의 데이터에 대해 산술 계산을 수행하는 응용의 수행속도를 개선하기 위하여 이중 CPU PC 상에서 Matlab의 기본연산, 즉 행렬 곱하기, 역행렬 계산, 의사 역행렬 계산 등을 병렬로 수행하는 라이브러리 프로그램을 구현하고 그 성능을 측정한다. 구현된 라이브러리는 행렬의 곱하기, 역행렬 계산, 의사 역행렬 계산 등 기본적인 행렬 연산에 대해 각 CPU에서 수행될 쓰레드를 생성하고 이 쓰레드에 분할 행렬을 인자로 넘겨줌으로써 병렬 계산을 실행하도록 하고 부분 결과를 합성하여 최종적인 결과를 산출하게 된다. 구현된 코드를 수행시켜 속도를 측정한 결과 행렬의 곱하기는 최대 69%, 역행렬은 34.8 %, 의사 역행렬은 52 % 까지 수행시간을 단축시켰다. 이에 의해 전기 단층 촬영 프로그램은 한번의 전류 주입에 대해 영상 복원에 소요되는 시간을 48 %로 감소시켰다.

• Journal of Chest Surgery
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• v.35 no.10
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• pp.740-744
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• 2002

Retrograde cerebral perfusion under hypothermic circulatory arrest is a simple and useful adjunct to avoid cerebral ischemic injury in the treatment of aortic arch pathology. In the surgery of distal aortic arch and proximal descending aortic lesions through the left thoracotomy incision, right atrium-retrograde cerebral perfusion (RA-RCP) through a venous cannula positioned into the right atrium is simpler than retrograde cerebral perfusion through superior vena cava. The time limits for RA-RCP during aortic arch reconstruction have yet to be clarified. We, herein, present a case with uneventful recovery after RA-RCP of 94 minutes during reconstruction of aortic arch and descending aorta. These data suggest that RA-RCP, as an adjunct to hypothermic circulatory arrest, may prolong the circulatory arrest time and thus prevent ischemic injury of the brain, even when RA-RCP exceeds 90 minutes.

• Journal of the Korean Orthopaedic Association
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• v.56 no.5
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• pp.377-390
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• 2021

Reverse total shoulder arthroplasty (RTSA) is a surgical method that has recently been conducted in widely irrepairable rotator cuff tears with pseudoparalysis, cuff tear arthropathy, and osteoarthritis of the shoulder joint. Several topics can be described, but this review article provides an opinion on the criteria for the choice of implant in RTSA.

• Journal of Chest Surgery
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• v.37 no.10
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• pp.861-864
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• 2004

Coronary sinus injuries related to the use of retrograde cardioplegia are rare and have potentially lethal complications. This report describes a case of coronary sinus laceration during retrograde cardioplegia in an old patient with mitral valve regurgitation, endocarditis, and left ventricular hypertrophy, and tells the details of the method of intracardiac repair.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.321-323
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• 1998

이 논문에서는 크기가 큰 III-Conditioned Matrices 정방행렬의 좌측 또는 우측 역행렬 계산시 계산상의 정확도를 향상시키는 알고리듬에 대하여 기술한다. 이 알고리듬은 대상 행렬의 행벡터들을 Input으로 하고 해당 Input 벡터가 몇번째 행 벡터인지를 나타내는 단위 벡터를 Target 벡터로 하며 초기 Weight 값으로 Pivoting을 겸한 Gauss소거법을 적용하여 얻은 역행렬을 사용하는 Single Layer 인공신경망에 적용하는 역전파 알고리듬과 흡사한 것이다. 각각의 Input 행 벡터에 대하여 역행렬의 열 벡터들이 점진적으로 직교가 되거나 평행이 되도록 근접시키므로써 모든 Input 행 벡터들이 열벡터들에 비교적 균일하게 직교 또는 평행이 되도록 학습시키는 알고리듬이다.

• The Korean Journal of Financial Management
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• v.16 no.2
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• pp.157-178
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• 1999

본 연구는 B/M, E/P, C/P, S/P 등이 높은 주식(가치주)을 매입하는 전락, 즉 역행투자전략 또는 가치전략의 투자성과가 B/M, E/P, C/P, S/P 등이 낮은 주식(성장주)을 매입하는 전략, 즉 성장전략의 투자성과보다 높게 나타나는지를 확인하고 그 원인을 살펴보았다. 실증분석결과에 의하면 가치주에 투자하는 역행투자전략의 투자성과는 지속적으로 크게 나타나며, 통계적으로도 유의한 것으로 나타났다. 한편, 가치주의 위험도는 성장주에 비해 상대적으로 높게 나타나고 있으나, 그 위험차이에 의해 높은 수익률차이를 설명할 수 없는 것으로 보인다. 결론적으로 가치주를 매입하는 전략, 즉 역행투자전략에 의해서 높은 투자성과를 얻을 수 있으며, 이는 위험보다는 투자자들의 비합리적인 부분최적화 행동(suboptimal behavior)에 기인한 것으로 판단된다.

• Journal of the Korean Orthopaedic Association
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• v.56 no.5
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• pp.367-376
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• 2021

An increasing number of reverse total shoulder arthroplasty procedures has been performed since its introduction to South Korea in 2007. This review discusses the biomechanical rationale behind the development of reverse total shoulder arthroplasty and its outcomes over time. In addition, this paper mentions ways to minimize the risk of complications that may occur and how to manage those complications.

• Clinics in Shoulder and Elbow
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• v.14 no.1
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• pp.125-133
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• 2011

Purpose: The purpose of the present article is to help orthopedic surgeons better understand the function and performance of reverse total shoulder arthroplasty, and also to help them perform the most proper surgical technique for reconstruction. Materials and methods: In this article, the specific technical aspects and pitfalls of reverse total shoulder arthroplasty were reviewed in depth. Additionally, the current issues relevant to the reverse total shoulder arthroplasty such as scapular notching and restoration of active external rotation were discussed. Results and conclusion: An understanding of the biomechanics of reverse total shoulder arthroplasty and the technical details and pitfalls of its implantation are critical in order to provide the best functional outcome without increasing the risk of complications.

• Journal of Chest Surgery
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• v.34 no.9
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• pp.653-661
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• 2001

Background: Retrograde cerebral perfusion(RCP) is one of the methods used for brain protection during aortic arch surgery. The author previously published the data, however, for the safety of it, there still remains many controversies. The author performed RCP and checked various parameters to clarify the possibility of early detection of cerebral injury. Material and Method: The author used pigs(Landrace species) weighing 25 to 30kg and performed RCP for 120 minutes. After weaning of cardiopulmonary bypass, we observed pigs for another 120 minutes. Rectal temperature, jugular venous oxygen saturation, central venous pressure were continuously monitored, and the hemodynamic values, histological changes, and serum levels of neuron-specific enolose(NSE) and S100$\beta$ protein were checked. Central venous pressure during RCP was maintained in the range of 20 to 25 mmHg. Result: Flow rates(ml/min) during RCP were 224.3$\pm$87.5(20min), 227.1$\pm$111.0(40min), 221.4$\pm$119.5(60min), 230.0$\pm$136.5(80min), 234.3$\pm$146.1(100min), and 184.3$\pm$50.5(120min). Serum levels of NSE did not increase after retrograde cerebral perfusion. Serum levels of S100$\beta$ protein(ng/ml) were 0.12$\pm$0.07(induction of anesthesia), 0.12$\pm$0.07(soon after CPB), 0.19$\pm$0.12(20min after CPB), 0.25$\pm$0.06(RCP 20min), 0.29$\pm$0.08(RCP 40min), 0.41$\pm$0.05(60min), 0.49$\pm$0.03(RCP 80min), 0.51$\pm$0.10(RCP 100min), 0.46$\pm$0.11(RCP 120min), 0.52$\pm$0.15(CPBoff 60min), 0.62$\pm$0.15(60min after rewarming), 0.76$\pm$0.17(CPBoff 30min), 0.81$\pm$0.20(CPBoff 60min), 0.84$\pm$0.23(CPBoff 90min) and 0.94$\pm$0.33(CPBoff 120min). The levels of S100$\beta$ after RCP were significantly higher than thosebefore RCP(p<0.05). The author could observe the mitochondrial swellings using transmission electron microscopy in neocortex, basal ganglia and hippocampus(CA1 region). Conclusion: The author observed the increase of serum S100$\beta$ after 120 minutes of RCP. The correlation between its level and brain injury is still unclear. The results should be reevaluated with longterm survival model also considering the confounding factors like cardiopulmonary bypass.

• Clinics in Shoulder and Elbow
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• v.14 no.1
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• pp.105-110
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• 2011

Purpose: The purpose of this article is to identify and understand the complications of RTSA and to review the current methods of preventing and treating this malady. Materials and Methods: Previous constrained prostheses (ball-and-socket or reverse ball-and-socket designs) have failed because their center of rotation remained lateral to the scapula, which has limited of the motion of the prostheses and produced excessive torque on the glenoid component, and this leads to early loosening. The Grammont reverse prosthesis imposes a new biomechanical environment for the deltoid muscle to act, thus allowing it to compensate for the deficient rotator cuff muscles. Results: The clinical experience does live up to the lofty biomechanical concept and expectations: the reverse prosthesis restores active elevation above $90^{\circ}$ in patients with a cuff-deficient shoulder. However, external rotation often remains limited and particularly in patients with an absent or fat-infiltrated teres minor. Internal rotation is also rarely restored after a reverse prosthesis. Failure to restore sufficient tension in the deltoid may result in prosthetic instability. Conclusion: Finally, surgeons must be aware that the results are less predictable and the complication/revision rates are higher in revision surgery than that in the first surgery. A standardized monitoring tool that has clear definitions and assessment instructions is surely needed to document and then prevent complications after revision surgery.