• Journal of Chest Surgery
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• v.27 no.5
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• pp.390-393
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• 1994

의료기술의 발달로 오늘날의 개심술은 대부분 성공적으로 시행되고 있지만 극히 일부분은 아직도 개심술후 심한 심실기능의 저하로 사망하는 겨우가 있다. 1960년대 중반 Spencer와 DeBakey에 의해 개심술후 심한 심실기능이 저하된 환자에게 심실보조장치를 이용하여 성공적으로 치험한 이후로 많은 발전을 거듭해 왔다. 저자들은 4개월 (6.5Kg)된 남아에서 개심술후 심한 저심박출증으로 인공심폐기의 제거를 못하여 좌심실 보조장치(Centrifugal Biopump)를 사용하여 성공적으로 치험하였기에 보고하는 바이다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.6
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• pp.469-475
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• 2017

Workers in industrial fields are highly exposed to accidents or injuries caused by long working hours. An exoskeleton that is able to support the arm muscles of the worker and thereby reduce the probability of an accident and enhance working efficiency could be a solution to this problem. However, existing exoskeletons demand the use of high-priced sensors and motors, which makes them difficult to use in industrial fields. To solve this problem, we developed an arm assisting exoskeleton that consists only of mechanical components without any electronic sensors or motors. The exoskeleton follows the movement of the human arm by shoulder joint and ankle joint. In addition, counterbalance mechanisms are installed on the exoskeleton to support arm strength. The experimental validation of the exoskeleton was conducted using an EMG sensor, confirming the performance of the exoskeleton.

• Journal of Chest Surgery
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• v.40 no.7 s.276
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• pp.512-516
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• 2007

A mechanical circulatory support system is a life-saving option for treating acute severe respiratory failure or cardiac failure. There are currently a few types of assist devices and the Twin-Pulse Life Support (T-PLS) system is a kind of pulsatile pump. We report here on three patients with severe life threatening cardiopulmonary dysfunction who had the T-PLS system used as an assist device. The indications for applying the T-PLS system were continuing respiratory or cardiac failure in spite of maximal ventilatory and inotropic support. There were two patients with acute respiratory failure due to infection and one patient with cardiac failure due to acute myocarditis. One respiratory failure patient and one cardiac failure patient survived after applying the T-PLS system for 3 days and 5 days, respectively. The T-PLS system is useful as an assist device and it should be considered before multi-organ failure occurs.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1191-1198
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• 2011

The use of a ventricular assist device (VAD) can raise the one-year survival rate without cardiac transplantation from 25% to 52%. However, malfunction of the VAD system causes 6% of VAD patients' deaths, which could possibly be avoided through the development of new VADs in which VAD malfunctions do not affect the patient's heart movement or hemodynamic state. A conventional VAD has an impeller or vane for propelling blood that can allow blood to regurgitate when the propelling force is weaker than the aortic pressure. In this paper, we developed a new pulsatile conduit-shaped VAD that has two valves. This device removes the possibility of blood regurgitation and has a small stationary area even when the pumping force is extremely weak. We estimated the characteristics of the device by measuring the outflow and the pressure of the pump in in-vitro and in-vivo experiments.

• Journal of Chest Surgery
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• v.30 no.3
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• pp.247-252
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• 1997

Ten acute and chronic in vivo studies were utilized to develop a pneumatic ventricular assist device (VAD) as a bridge to heart transplantation or a circulatory assist device for patients with end-stage heart disease or poor myocardial funct on after cardiac surgery. Two sizes of blood pump of 70cc for adult patients and 34cc for pediatric patients were implanted in the animals. Ventricle of the blood pump was made from the polyurethaae to enhance antithrombogenecity. The VAD was implanted between the left atrium and the descending aorta. Average flow rate was 2.38 L/min for adult and 0.41 L/min for pediatric VAD at the rate of 60 bum. The duration of support ranged from 1 to 26 hours. The most frequent complication was bleeding. Main causes of death were heart failure and respiratory failure. The device function was good for short term use. Studies to date suggest that, with further refinement, a reliable long term VAD that will have clinical application can be developed.

• KIPE Magazine
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• v.14 no.5
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• pp.31-35
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• 2009

철도차량에는 여러 형태의 전력 변환 장치들이 존재하고 운영되고 있다. 전기철도차량에서는 차량의 동력원을 제어하는 추진제어장치와 각종 콤프레서를 동작하는 인버터, 차량의 전원으로 사용되는 정지형 인버터 등이 주요 전력 변환장치라고 할 수 있으며 이중에서 챠량의 전원과 밧데리 충전을 위한 장치인 전기 철도차량의 보조전원용 전력변환장치의 종류들과 변화 과정들을 소개 하고자 한다.

• Journal of Chest Surgery
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• v.34 no.5
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• pp.403-406
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• 2001

본 증례는 66세(51.8kg)된 남자에서 수술전 심한 좌심실 기능 부전과 승모판 및 삼첨판 폐쇄부전이 있어 개심술 시행후 심한 저심박출증 발생으로 인공심폐기 이탈에서 실패하고 양심실 보조장치(Centrifugal Biopump)를 사용한 후 이로부터 성공적인 이탈과 퇴원이 보고하는 바이다.

• Membrane Journal
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• v.14 no.1
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• pp.18-25
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• 2004

The purpose of this paper was to find out the proper equation to predict the gas transfer rate for designing intravenous artificial lung assist device. The prepared hollow fiber modules were examined under various experimental conditions through experimental modeling before inserted the artificial lung assist d $\varepsilon$ vice into as venous. As a result, we can estimate the gas transfer as a function of the packing density. The gas transfer obtained from the experiment was similar to that from the equation, confirming the usefulness equation. Therefore, we can conclude the gas transfer of the intravenous artificial lung assist device as a function of the packing density, and this functions are very useful for predicting the gas transfer of the intravenous artificial lung assist device.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.117-119
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• 1995

서울대학교 의공학과에서는 부분적인 심부전 판자의 보조 및 치료장비로 전기유압식 좌심실 보조 장치를 개발하고 있다. 이 장비의 경우 인체의 좌심방 및 대동맥에 직접 연결되므로 실제적으로 좌심실 보조 장치의 박출량을 센서를 통하여 알아내는 데에는 여러가지 어려움이 따른다. 이러한 필요성에 비추어 전기유압식 좌심실 보조 장치의 박출량을 시스템을 ARX모델로 모델링하여 RLS(Recursive Least Square) 알고리듬을 이용하여 추정하였다. 그 결과 비교적 높은 정착도로 박출량이 추정됨을 볼 수 있었다. 하지만, ARX모델의 특성상 원래 본 연구의 시작과정에서 분석한 시스템의 동적 특성을 완전하게 반영할 수 없었다. 앞으로 시스템의 파라미터 추정 과정에서 이미 주어진 동적 특성은 고정시키고 나머지 파라미터들만을 추정하는 알고리듬을 개발하는 것도 흥미로운 과제라 할 수 있다.

• Journal of Biomedical Engineering Research
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• v.19 no.1
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• pp.39-46
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• 1998

In this paper, we present a neural network identification and a control of highly complicated nonlinear left ventricular assist device(LVAD) system with a pneumatically driven mock circulation system. Generally, the LVAD system needs to compensate for nonlinearities. It is necessary to apply high performance control techniques. Fortunately, the neural network can be applied to control of a nonlinear dynamic system by learning capability. In this study, we identify the LVAD system with neural network identification(NNI). Once the NNI has learned the dynamic model of the LVAD system, the other network, called neural network controller(NNC), is designed for a control of the LVAD system. The ability and effectiveness of identifying and controlling the LVAD system using the proposed algorithm will be demonstrated by computer simulation.