• 대한의용생체공학회:의공학회지
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• 제23권1호
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• pp.33-38
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• 2002

심실보조장치(ventricular assist device, VAD)는 그 특성상 손상된 자연심장의 기능을 보조하기 위해서 사용된다. 따라서, 심실보조장치의 제어 알고리즘을 고려할 때에는 가능한 한 자연심장에 걸리는 부하를 최소한으로 줄여주는 것이 중요하다. 이처럼 자연심장에 걸리는 부하를 줄여주기 위해 가장 일반적으로 사용되는 제어 방식이 바로 자연심장과 심실보조장치 상호간의 동시 박출을 방지하는 counterpulsation 제어 방식이다. 실제로 Nanas[1][2] 등은 동물실험을 통해 좌심실이 손상된 상황에서 counterpulsation 장cl가 혈류역학적으로 어떠한 영향을 미치는가를 연구하였다 본 연구에서는, 현재 서울대학교 인공심장연구실과 (주)바이오메드랩에서 공동으로 개발 중인 이동작동기형 심실보조장치 (AnyHeart/ sup TM/)에 사용할 수 있는 counterpulsation 제어 알고리즘을 개발하고. 개발된 알고리즘을 실제 동물 실험에 적용하기에 앞서 모의순환장치를 이용하여 개발된 알고리즘의 효용성을 검증하여 보았다. 자연심장의 박출 상태를 실시간으로 파악하기 위해 심전도(electrocardiogram, ECG) 신호를 입력으로 받아들여 제어를 수행하는 방식을 채택하였으며, 모의순환장치에서의 실험 결과 심실보조장치와 자연심장 간의 동시 박출 방지 효과가 정상적으로 일어남을 확인할 수 있었다.

• IEIE Transactions on Smart Processing and Computing
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• 제1권3호
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• pp.192-200
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• 2012

In order for humans and robots to interact in daily life, robots need to understand human speech and link it to their actions. This paper proposes a hierarchical behavior model for robot action control using natural language commands. The model, which consists of episodes, primitive actions and atomic functions, uses a sentential cognitive system that includes multiple modules for perception, action, reasoning and memory. Human speech commands are translated to sentences with a natural language processor that are syntactically parsed. A semantic parsing procedure was applied to human speech by analyzing the verbs and phrases of the sentences and linking them to the cognitive information. The cognitive system performed according to the hierarchical behavior model, which consists of episodes, primitive actions and atomic functions, which are implemented in the system. In the experiments, a possible episode, "Water the pot," was tested and its feasibility was evaluated.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2005년도 추계학술대회 학술발표 논문집 제15권 제2호
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• pp.238-241
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• 2005

최근 컴퓨터를 이용하여 효과적인 트레이드를 하려는 투자자들이 늘고 있다. 본 논문에서는 많은 인공지능 방법론 중에서 강화학습(reinforcement learning)을 이용하여 효과적으로 트레이딩하는 방법에 대해서 다루려한다. 특히 강화학습 중에서 natural policy gradient를 이용하여 actor의 파라미터를 업데이트하고, value function을 효과적으로 추정하기 위해 RLS(recursive least-squares) 기법으로 critic 부분을 업데이트하는 RLS 기반 natural actor-critic 알고리즘을 이용하여 트레이딩을 수행하는 전략에 대한 가능성을 살펴 보기로 한다.

• 한국임상수의학회지
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• 제16권1호
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• pp.150-154
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• 1999

This study was designed to examine the therapeutic effect of Italian honeybee (Apis mellifera) venom in piglets with bacterial diarrhea. Preweaning piglets were assigned to treated and nontreated control groups. In treated group, 47 piglets were given natural honeybee venom once a day for 3 consecutive days. The natural honeybees were stung acupoints of GV-1 (Jiao-Chao, at the indentation between the base of tail and the anus) and ST-25 (Hai-men, about 1 cm lateral to the umbilicus). In control group, 44 piglets were intramuscularly injected with a standard dosage of colistin sulfate (300,000 IU/kg of body weight) and antid-iarrheal drug (berberine, 2 ml/kg) once a day for 3 consecutive days. At post-treatment, 90.9% of control piglets and 93.6 % of piglets in treated group recovered from bacterial diarrhea. Bee acupuncture therapy did not show in piglets without any side effects such as allergy, intoxication, hemorrhage, or infection. It might be concluded that honeybee venom therapy was effective in controlling of piglets with bacterial diarrhea.

• 대한약학회:학술대회논문집
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• 대한약학회 2001년도 Proceedings of the Pharmaceutical Society of Korea
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• pp.215-215
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• 2001

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.420-424
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• 1994

In this paper, an active suspension system considering the wheel hop is studied for a quarter car model. A LQ controller controls an active suspension system in which a vibration absorber is attached to the wheel axis. The vibration absorber is adopted to reduce the vibration near the natural frequency of the unsprung mass, and the LQ controller is used to control the vibration near the natural frequency of the sprung mass. The perfomance of the control system considering the wheel hop is compared with that of a LQ control system.

• 한국공간구조학회논문집
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• 제12권4호
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• pp.99-108
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• 2012

In recently, sky-bridge are often applied to high-rised adjacent buildings for pedestrian bridge. the seisnic response control of adjacent buildings have been studied and magneto-rheological(MR) fluid dampers have been applied to seismic response control. In this study, vibration control effect of the MR damper connected adjacent buildings has been investigated. Adjacent building structures with different natural frequencies were used as example structures. Two typed of control methods, displacement based or velocity based, are applied to determinate control force of MR damper. In this numerical analysis, it has been shown that displacement-based control algorithm is more effective than velocity-based control algorithm for seismic response control of adjacent buildings. And, when displacement-based control method is applied to control of adjacent buildings, the control of building occurred large displacement is more efficient in reducing the seismic response.

• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 1996년도 제19회정기학술대회(The 19th Symposium of the Korean Society of Environmental Toxicology)
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• pp.71-71
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• 1996

• 한국기계가공학회지
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• 제15권2호
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• pp.51-56
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• 2016

High brittleness is a characteristic of glass, and in many cases it is broken during the process of machining due to processing problems, such as scratches, chipping, and notches. Machining defects occur due to the vibration of the equipment. Therefore, design techniques are needed that can control the vibration generated in the equipment to increase the strength of tempered glass. The natural frequency of the machine tool via vibration analysis (computer simulation) must be accurately understood to improve the design to ensure the stability of the machine. To accurately understand the natural frequency, 3D modeling, which is the same as actual apparatus, was used and a constraint condition was also applied that was the same as that of the actual apparatus. The maximum speeds of ultrasonic and high frequency, which are 15,000 rpm and 60,000 rpm, respectively, are considerably faster than those of typical machine tools. Therefore, an improved design is needed so that the natural frequency is formed at a lower region and the natural frequency does not increase through general design reinforcement. By restructuring the top frame of the glass processing, the natural frequency was not formed in the operating speed area with the improved design. The lower-order natural frequency is dominant for the effects that the natural frequency has on the vibration. Therefore, the design improvement in which the lower-order natural frequency is not formed in the operating speed area is an optimum design improvement. It is possible to effectively control the vibrations by avoiding resonance with simple design improvements.

• The Plant Pathology Journal
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• 제17권6호
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• pp.384.4-385
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• 2001