• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.1112-1118
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• 2007

This paper investigates the performance of an electromagnetic type active control engine mount (ACM) recently developed in the laboratory. The ACM employs the basic structure of the conventional hydraulic engine mount of which upper chamber is connected to a dual magnet electromagnetic actuator. The actuator, that essentially replaces the existing decoupler of the conventional passive hydraulic engine mount, actively controls the upper chamber pressure. Using the linearized ACM model incorporated with the actuator dynamics, we suggest an optimal design of ACM, maximizing the actuator efficiency as well as the vibration isolation efficiency.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.322-322
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• 2010

In this paper, we propose a novel type valveless micro-pump that uses extensional vibration mode of traveling wave as a volume transporting means for solving some problems about check valves, essential parts of usual pumps. The proposed pump consists of two piezoelectric ceramic rings and a metal body located in the middle of them respectively. Because the drift of bended surface that results from the traveling wave excitation controls the fluid flow, check valves are not needed in this pump model. In accordance with the variation of the pump body dimension, we analyzed the vibration displacement characteristics of pump model, determined the optimal design condition, fabricated the prototype pump from the analysis results and evaluated its efficiency.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• 제6권1호
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• pp.30-37
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• 2003

This paper describes vibration control of a suspended system using wave absorption method. A moving multiple-pendulum system and a moving wire-and-load system are treated. The wire-and-load system is extended to a model crane system that has a motor system to roll up and down the suspended mass like a real crane. The same program with different parameter values controls these three systems. Both numerical simulation and experiment have been conducted, and the present control method has shown to be quite effective.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.581-586
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• 2004

This paper presents Newtonian formulation of the dynamics of plates treated fully with Active Constrained Layer Damping (ACLD). The developed equations of the plate/ACLD system provide analytical models far predicting the dynamic of laminated plates subjected to passive and active vibration damping controls. Numerical solutions of the analytical models are presented fir simply-supported plates in order to study the performance of the plate/ACLD system for different control strategies. The developed models present invaluable means for designing and predicting the performance of the smart laminated plates that can be used in many critical engineering applications.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 춘계학술대회 논문집
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• pp.28-32
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• 1992

The elimination of chatter vibration is necessary to improve the precision and the productivity of the cutting operation. A new mathematical model of chatter vibration is pressented in order to predict dynamic cutting force from static cutting data. Chatter vibration occurring in the tool structure of lathe is treated theoretically, considering the regenerative effect. The Stability Analysis is carried out by a two degress of freedom system. The dynamic cutting force is analytically expressed by the static cutting coefficient and the dynamic cutting coeccicient which can be determined from the cutting mechanics. The static cutting coefficient controls high speed chatter stability, while the dynamic cutting coefficient dominates low chatter stability. From above considerations, the cirtical width of cut which governs chatter stability was obtained.

• 화약ㆍ발파
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• 제27권1호
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• pp.38-46
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• 2009

최근 진동 소음을 저감하는 공법으로 초시의 정확성과 초시부여의 자율성을 가진 전자뇌관을 이용하는 공법(OBM ; Orechestra Blasting)이 소개되었다. 파형합성프로그램은 전자뇌관의 지연초시를 결정할 수 있으며 결정된 초시를 이용하여 실 발파와 유사한 환경에서의 시뮬레이션을 수행, 최적초시 상태의 진동 속도를 예측할 수 있다. 본 연구에서는 파형합성프로그램을 통해 진동을 제어하는 최적초시를 얻고 실제 발파작업 시의 진동치를 예측하고자 하였다.

• KIEE International Transaction on Systems and Control
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• 제2D권2호
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• pp.65-71
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• 2002

In this paper, an experiment for the active vibration control of a cantilever beam uses electromagnet as an actuator and uses a laser sensor to measure the position of the bending beam, constituting a non-contacting control system. A mathematical model of the overall system is derived to analytically design an appropriate controller. Dynamic equations of the electromagnetic actuator and the beam are combined to find the transfer function from the actuator to the sensor. The effectiveness of the obtained model is verified by various experiments and an improper PID controller is designed based on the obtained model. According to analysis, the coefficient of the derivative controller is the most important parameter for handling the performance and the stability margin of the control system. The experimental results of the active control system are compared with those of the open loop system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.694-699
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• 2002

As the demand for slim laptops requires ion'-height optical disc drives, vibration problems of optical disc drives are of great concern. Additionally, with the decrease of a track width and a depth of focus in high density drives, studies on vibration resonance between mechanical parts become more important. From the vibration point of view, the performance of optical disc drives is closely related with the relative displacement between a disc and an objective lens which is controlled by servo mechanism. In other words, to read and write data properly, the relative displacement between an optical disc and an objective lens should be within a certain limit. The relative displacement is dependent on not only an anti-vibration mechanism design but also servo control capability. Good servo controls can make compensation for poor mechanisms, and vice versa. In a usual development process, robustness of the anti-vibration mechanism is always verified with the servo control of an objective lens. Engineers partially modify servo gain margin in case of a data reading error. This modification cannot correct the data reading error occasionally and the mechanism should be redesigned more robustly. Therefore it is necessary to verify a mechanism with respect to the possible servo gain plot. In this study we propose the experimental verification method far anti-vibration mechanism with respect to the existing servo gain plot. This method verifies axial vibration characteristics of optical disc drives on the basis of transmissibility. Using this method, we verified our mechanism and modified the mechanism for better anti-vibration characteristics.

• 한국소음진동공학회논문집
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• 제12권11호
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• pp.833-839
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• 2002

As the demand for slim laptops requires low-height optical disc drives, vibration problems of optical disc drives are of great concern. Additionally, with the decrease of a track width and a depth of focus in high density drives, studies on vibration resonance between mechanical parts become more important. From the vibration point of view, the performance of optical disc drives is closely related with the relative displacement between a disc and an objective lens which is controlled by servo mechanism. In other words, to read and write data properly, the relative displacement between an optical disc and an objective lens should be within a certain limit. The relative displacement is dependent on not only an anti-vibration mechanism design but also servo control capability. Good servo controls can make compensation for poor mechanisms, and vice versa. In a usual development process, robustness of the anti-vibration mechanism is always verified with the servo control of an objective lens. Engineers partially modify servo gain margin in case of a data reading error. This modification cannot correct the data reading error occasionally and the mechanism should be redesigned more robustly. Therefore it is necessary to verify a mechanism with respect to the possible servo gain plot. In this study we propose the experimental verification method for anti-vibration mechanism with respect to the existing servo gain plot. Thismethod verifies axial vibration characteristics of optical disc drives on the basis of transmissibility. Using this method, we verified our mechanism and modified the mechanism for better anti-vibration characteristics.

• Physical Therapy Rehabilitation Science
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• 제3권2호
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• pp.86-92
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• 2014

Objective: Whole body vibration (WBV) and plyometrics are common training techniques which increase strength, blood flow, and lower body force and power. The effects these techniques have on sedentary population is unknown. It is our aim to assess the effectiveness of WBV and plyometrics on sedentary population. Design: Experimental study. Methods: Twenty-seven sedentary subjects were assigned to either the control group, jumping only group, or jumping with vibration group. Jump height (myotest or vertec), velocity, force, blood lactates, and rating of perceived exertion (RPE). Subjects were measured on the initial, seventh, and eighteenth visits. Control group attended measurements only. Jumping only and jumping with vibration groups performed jumping from a vibrating platform to a surface 7 1/2 inches higher for 3 bouts of 20 seconds. Each subject in jumping only and jumping with vibration groups attended three times per week for six weeks. Vibration was set at 40 Hz and 2-4 mm of displacement. Results: There was no significant change among groups in force, velocity, vertec height, and myotest height. However there was a significant increase in vertec height from initial to final measure (p<0.05) for jumping with vibration group. RPE was significantly higher between control group and jumping with vibration group after intervention (p<0.05). Conclusions: WBV with vibration increased jump height. Jumping with vibration group experienced increased exertion than for controls. WBV with plyometrics had no effect on force, velocity, blood lactates, or calculated jump height. Further studies controlling for initial measure of blood lactates and using an external focus may be necessary to elicit velocity, force and jump height changes.