• 한국소음진동공학회논문집
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• 제21권5호
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• pp.475-483
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• 2011

A hybrid electromagnetic actuator with an air mount is designed so as to achieve the desired isolation reduce the vibration efficiency on the floor vibration. The performance specification of the hybrid electromagnetic actuator is determined based on the vibration criterion for vibration-sensitive equipment. In the design stage of the electromagnetic actuator, the simple reluctance method is adapted to analyze magnetic circuits. The result is verified by finite element analysis using ANSYS Emag. Finally, in order to confirm the design performance, a dynamic characteristic test is carried out for the prototype of a hybrid electromagnetic actuator.

• 한국소음진동공학회논문집
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• 제26권4호
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• pp.391-397
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• 2016

Vibration disturbances induced by the reaction wheels can severely degrade the performance of high precision payloads on board satellites with high pointing stability requirements. The unwanted disturbances produced by the reaction wheels are composed of fundamental harmonic disturbances due to the flywheel imbalance and sub/higher harmonic disturbances due to bearing irregularities, motor imperfections and so on. Because the wheel speed is constantly changed during the operation of a reaction wheel, the vibration disturbance induced by the reaction wheels can magnify the satellite vibration when the rotating frequency of wheel meets the natural frequency of satellite structure. In order to provide an effective isolation of the reaction wheel disturbances, isolation performance of a hybrid vibration isolator is investigated. In this paper, hybrid vibration isolator that combines passive and active components is developed and its hybrid isolation performance using notch filter control is evaluated in single-axis. The hybrid isolation performance using notch filter control show additional performance improvement compared to the results using only passive components.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1993년도 가을 학술발표회 논문집
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• pp.207-212
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• 1993

When constructing highly precise production plants, for example, super LSI plants or semiconductor plants, it is important to take the necessary control countermeasures into consideration to obtain the working microvibration environment, which is directly related to product precision. Working environment of a clean room means vibration-free and there are only ultra-miro vibration which human cannot sense. In order to provide an place having a vibration-free working environment with only ultra-micro vibration it is necessary to posses a great number of vibration isolation technlogies, wide-ranging and abundant survey and teat data, and a high level of knowledge enabling comprehensive judgments to be made. In this study, experimental modal analysis is used to analyze the dynamic characteristics of double floor for vibration-proofing near apparatus which generate vibration. It is concluded that the double floor system with rubber pad inserted between floor panel and pedestal is good for vibration proof.

• 인간식물환경학회지
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• 제22권6호
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• pp.611-619
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• 2019

This study was conducted to investigate changes in the mental functions of the elderly in nursing facilities affected by a horticultural therapy program based on validation therapy. To meet the purpose, we conducted a horticultural therapy program based on validation therapy with 58 elderly participants (average age 79.12±6.84, men and women) once a week, 50 minutes per session, in a total of 10 sessions. Participants were divided into the control and experimental group with convenience sampling. The program was carried out from March 15 to November 22, 2018. Vibraimage 8 pro(ELSYS, 2014) is a recent, psychologically based, emotional-recognition visual imaging technology that measures pixels microvibration in terms of digital frequency and amplitude parameters. To examine the effects of the horticultural therapy program based on validation therapy, Vibraimage was used to assess aggression, stress, tension, suspect, balance, charm, energy, self-regulation, inhibition, neuroticism and positive, negative, physiological domains of mental functions before and after program. As a result, the mean score of the positive domain in the control group significantly decreased from 63.89±5.09 to 60.74±5.48, but it decreased without statistical significance in the experimental group from 63.98±5.45 to 61.39±6.02. The mean score of neuroticism in the experimental group significantly decreased from 31.64±10.94 to 22.87±13.79. Moreover, the mean score of the physiological domain in the experimental group also significantly decreased from 25.08±6.27 to 19.42±8.80. Accordingly, horticultural therapy program based on validation therapy can be utilized as a program to promote mental health, especially maintaining positive mental health function of the eldery, helping those who live in long-term care facilities enjoy a happier life more happier.