• 한국추진공학회지
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• 제21권5호
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• pp.88-96
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• 2017

재생냉각 기술을 적용한 스크램제트 엔진 개발의 일환으로 스크램제트 엔진에 사용될 공기 보조형 인젝터(Air-assist type injector)에 대한 연구를 수행하였다. 실험에 사용된 인젝터는 주 유동에 대해 $90^{\circ}$와 $60^{\circ}$의 각도로 분출되는 두 종류의 인젝터를 사용하였으며 측정 방법에는 미 산란(Mie-scattering)을 이용한 가시화 측정방법과 PDPA를 이용한 미립화 측정 방법을 사용하였다. 실험 결과, 공급되는 기체의 압력 증가와 노즐로부터의 거리가 증가할수록 더 좋은 미립화 특성을 보였으며 분출각도가 $60^{\circ}$인 인젝터가 $90^{\circ}$의 인젝터보다 더 좋은 미립화 특성을 보였다.

• 한국기계가공학회지
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• 제11권1호
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• pp.33-38
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• 2012

An experimental study was carried out to observe the characteristics of impingement of assist gas from a rectangular supersonic nozzle on kerf surface in laser machining. A micro-scale supersonic (Mach number 2.0) rectangular nozzle system was designed and fabricated for the purposes, and hot tests of the performance of the nozzle system was proceeded in the ITI corporation laboratory. For various related parameters such as laser powers, nozzle pressures and cutting speeds, the quality of the frontal view of cut edge surfaces was observed by a microscope. In the study, it was shown that the application of the present micro-rectangular supersonic nozzle in an off-axis configuration made it possible to cut a mild steel, by combinations of relatively low laser - powers, large standoff distances, and assist gas with no oxygen, which was not achieved by conventional laser cutting processes.

• 드라이브 ㆍ 컨트롤
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• 제18권4호
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• pp.72-76
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• 2021

The aim of this study was to establish a breathing assist system for saxophone players with breathing problems. Although the saxophone is a popular wind instrument with a reed in its mouthpiece, it can be difficult for people with breathing problems to play this instrument, as it requires adequate breath support for deep and even long breaths. To solve this problem, the authors propose a breathing assist device, which functions like a pneumatic master-slave amplifier, for saxophone players with breathing problems. First, the proposed device is fabricated. Second, the effectiveness of the breathing assist device as a master-slave amplifier is confirmed through experiments. Third, the dynamic characteristics of the device are tested up to 10 Hz, and they demonstrate that the device responds well for up to approximately 5 Hz.

• 제어로봇시스템학회논문지
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• 제16권6호
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• pp.532-538
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• 2010

SD (Smart Door) is a human friendly power-assisted door system initially targeted for passenger car doors. The Smart Door offers comfort and safety to passengers or/and drivers by supplying additional power. Amount of power supplied by the Smart Door system is depend on the environment where the automotive is situated. It realizes comfort, for example, when the force applied by the passenger to the door is expected to be abnormal, the SD system tries to compensate passenger's effort by supplying additional force. In this study, to enhance the ease of opening and closing the doors of the passenger vehicle, a Smart Door with a power assist mechanism consisting of a motor was developed and analysed. A power assist mechanism mounted within the vehicle's door is designed and modeled for simulation purpose. The required force necessary to control the designed mechanism during the vehicle's roll, pitch and the opening angle of the door has been considered. To this end, we propose a power-assisting control strategy called "gravity cancellation". The system is analysed by numerical simulation with the gravity cancellation control algorithm.

• 한국치위생학회지
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• 제9권2호
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• pp.147-163
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• 2009

This study was attempted in order to look into 'Assist work' as to Implant system which dental hygienists perform in a clinical field. Subjects of this research were 362 dental hygienists who work at general hospital, University hospital, dental hospital, and dental clinics located in Seoul, Kyeong-gi, In-chon, and Jeon-buk area. As to research tool, we produced questionnaire which was comprised of the total 25 items regarding 3 of general features (age, career of dental hygienist, and personality), 6 of implant system assist work, 3 of Informed consent before surgery, 6 of preoperative preparation and maintenance related business, and 7 items related to postoperative maintenance. By using SPSS program, collected data was analyzed. Results of analysis in this study were as follow; 1. As to implant related education, dental hygienists' experience of education was high as 77.7%, and the people who is needed more education was 86.3%. Consequently, dental hygienists' concern about the implant related education was very high. 2. It was observed that most of informed consent making approvement by announcement to the surgical operation was made by dental hygienist before implant as 95%. 3. Over 80% of dental hygienists performed acquisition of cleanliness technology, motivation, back up articles preparation, treatment area arrangement, and etc. which we can check by preoperative maintenance items. In particular, response about the motivation was very high as more than 90%. 4. When performing an operation, in the case of disinfecting finger was low for 53.9% and the method was mainly washing with drug solution, and gown sterilization was performed only in 52.2%. Therefore education regarding disinfection was urgently needed. 5. Significance of education could be known that answers of hygienists experienced education appeared highly in items of maintenance method and there was statistically significant difference(p<0.05). 6. In case that assist work were 21cases or greater, agitation measurement was the most many performed in 68.9% and difference was showed up significantly(p<0.001). 7. Evaluation about periodontal tissue was high in dental hygienists who had experienced education and also there was statistically significant difference. In conclusion, assist work of dental hygienists was very comprehensive when implant surgery was performed, and all of items excluding hand disinfection or gown disinfection were highly showed up in most of hygienists. However, since there is the limit that we didn't investigate the quality of performing contents. It is considered that further study regarding the content has to be progressed for supporting this result in the future.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.9-10
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• 2002

Human circulatory system between heart and tissue is not directly connected in normal condition but mandatory to go through the capillary system in order to fulfill its physiologic aim to deliver oxygen and nutrients, etc. to the tissue and retrieve used blood together with waste products from the tissue properly. When abnormal connection between arterial and venous system (AV fistula), these two circulatory systems respond differently to the hemodynamic impact of this abnormal connection between high pressure (artery) and low pressure (vein) system. Depending upon the location and/or degree (e.g. size and flow) of fistulous condition, each circulatory system exerts different compensatory hemodynamic response to this newly developed abnormal inter-relationship between two systems in order to minimize its hemodynamic impact to own system of different hemodynamic characteristics. Pump action of the heart can assist the failing arterial system directly to maintain arterial circulation against newly established low peripheral resistance by the AV fistula during the compensation period, while it affects venous system in negative way with increased venous loading. However, the negative impact of increased heart action to the venous system is partly compensated by the lymphatic system which is the third circulatory system to assist venous system independently with different hemodynamics. The lymphatic system with own unique Iymphodynamics based on peristaltic circulation from low resistance to high resistance condition, also increases its circulation to assist the compensation of overloaded venous system. Once these compensation mechanisms should fail to fight to newly established hemodynamic condition due to this abnormal AV connection, each system start to show different physiologic ${\underline{de}compensation}$ including heart and lymphatic system. The vicious cycle of decompensation between arterial and vein, two circulatory system affecting each other by mutually negative way steadily progresses to show series of hemodynamic change throughout entire circulation system altogether including heart. Clinical outcome of AV fistula from the compensated status to decompensated status is closely affected by various biological and mechanical factors to make the hemodynmic status more complicated. Proper understanding of these crucial biomechanical factors iii particular on hemodyanmic point of view is mandatory for the advanced assessment of biomechanical impact of AV fistula, since this new advanced concept of AY fistula based on blomechanical information will be able to improve clinical control of the complicated AV fistula, either congenital or acquired.

• 경영과정보연구
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• 제2권
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• pp.311-334
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• 1998

By decreasing in CPU price and development of computer assembling technology, personal computer fake a good chance to accelerate its supply. Recently, as being introduced new computing technology so called multi media, teaming assist system which is based on single media such as studying book, cassette tape, video tape, or something else is rapidly being replaced by new assist education system based on multi media in which it is operated by the personal computer. In the computer assist education system, there is an evaluation module which appraise learner's study level into the next study strategy. At the view of this point, this part is very important. In this part, there are some factors like Importance, complexity, or difficulty which commonly include fuzzy factors in our surrounding. But until now, we are still out of the level to handle the evaluation module adequately among the some studies. In this study, we would like to suggest a new module that evaluate learning achievement of ICAI which have a variety of fuzzy environment. We combine Independent fuzzy environment like importance, complexity, difficulty into making total evaluation of learner's achievement. By the result, with expressing by linguistic form, this study can provide the theoretical basis in which we will be able to carry out sentence toward evaluation among elementary school.

• Journal of Chest Surgery
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• 제54권6호
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• pp.543-546
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• 2021

A 55-year-old woman who had received an implantable left ventricular assist device 3 months earlier presented with dyspnea and a low-flow alarm of the device. Computed tomography and log-file analysis of the device system suggested inflow cannula obstruction. Since the patient had cardiogenic shock due to pump failure, venoarterial extracorporeal membrane oxygenation (ECMO) was initiated. With ECMO, surgical exchange of the pump was considered. However, the obstruction spontaneously resolved without surgical intervention. It turned out that an obstructive thrombus was washed out by rebooting the pump. Moreover, the thrombus was embolized in the patient's left subclavian artery. The patient underwent heart transplantation 4 months after the pump obstruction accident and continued to do well.

• 한국항행학회논문지
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• 제17권2호
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• pp.165-170
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• 2013

본 논문에서는 운전자의 주행습관 속에서 안전운전에 지원을 위한 정보 획득 및 분석 장치를 구현하였다. 안전운전 지원을 위하여 공격적 운전행동을 정의하고 운전 중 행동을 인식할 수 있는 정보 획득 방법을 고안하였다. 정보 수집 장치와 정보 분석모듈 그리고 운전행동 비교모듈을 설계하여 정보의 정확성을 높였으며. 운전자의 평소 운전행동과 비교하여 이상행동을 검출하여 경고할 수 있도록 시스템을 설계하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.277-278
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• 2006

As a development of technology, electric power steering system which uses an electric motor came to use in recent and it can solve the problems with hydraulic power steering system. In this paper, vehicle model and electric power steering system are combined to fulfill full vehicle model. By simulation effect of motor torque assist through electric power steering revealed effective, and full vehicle model are proved reasonable through comparison with real car experimental datum.