• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.600-601
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• 2008

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.565-573
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• 2007

This paper is concerned with the dynamic modeling, active vibration controller design and experiments for a cylindrical shell equipped with MFC actuators. The dynamic model was derived by using Rayleigh-Ritz method based on Donnel-Mushtari shell theory. The actuator and sensors for the MFC actuator equations were derived based on pin-force model. The equations of motion were then reduced to modal equations of motion by considering the modes of interest. The sensor equations were also converted to a reduced form. An aluminum shell was fabricated to demonstrate the effectiveness of modeling and control techniques. The boundary conditions at both ends of the shell were assumed to be shear diaphragm. Theoretical natural frequencies were calculated and compared to experimental result. It was observed that the theoretical result is in good agreement with experimental result for the first two modes. The multi-input and multi-output positive position feedback controller, which can cope with first two modes, was then designed based on the blockinverse theory and implemented using DSP. It was found from experiment that vibrations can be successfully suppressed.

• 대한정형도수물리치료학회지
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• 제6권2호
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• pp.31-38
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• 2000

The influence of the genu varum and the genu valgum in two groups of twenty adult man with deformation on hip joint, knee joint, ankle joint is as follows. 1. Each and all, the statistics that measure tibiofemorial angle indicated the group of the genu varum 168 1.42 and the group of the genu valgum 193 2.21, that was more larger or smaller than normal angle 183 of tibiofemorial. The measure Q-Angle(patellofemorial) indicates the group of the genu varum 9 1.5, the genu valgum 19 2.3, that was larger or smaller than normal angle 13. 2. It showed that range of motion hip joint adduction in the group of the genu varum was more larger than normal range of motion hip joint abduction in the group of the genu valgum was more larger than normal range of motion, hip joint internal rotation in the group of the genu valgum was more larger than normal range of motion, hip joint external rotation in the group of the genu varum was more larger than normal range of motion. 3. range of motion knee joint flexion was simillar to two groups of the genu varum and the genu valgum. On tibial tortion of the leg, the group of the genu varum indicated medial tibial tortion, and the genu valgum indicated lateral tibial tortion. 4. Each groups of the genu varum and the genu valgum in plantarflexion and dorsiflexion of ankle joint. With peak angle, the group of the genu varum showed toe-in that was more smaller than normal angle, and the group of the genu valgum showed toe-out that was more larger than normal angle.

• 대한조선학회논문집
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• 제52권6호
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• pp.452-459
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• 2015

It is important to use bench test results in the design process of anti-rolling tanks. Traditional bench tester is usually designed to perform only roll motions about a fixed axis and relatively small so that the viscous effects may not be neglected. Novel bench tester which could adjust the motion center to realize the coupled motion of sway and roll has been devised and manufactured therefore, large scaled bench tester could be utilized for designing the passive anti-rolling tanks. The time history of the reference signal from the rotation sensor of the bench tester have been recorded and processed to determine the phase angle to derive the Response Amplitude Operator(RAO) of the stabilized ship. The breadth of ART tank model should be large up to 2 m to diminish viscous scale effect and the vertical position of the tank can be varied with the ship's center of motion. The periods and the amplitude of roll motion can be varied from 1.5 sec to 5 sec and up to ±20°, respectively. The components of the tester was expressed in three dimensional digital mockup (DMU) and assembled together in the CAD space. The final configuration of the bench tester has been determined by confirming the smooth operation of the moving parts without interference through the animation in CAD space. New analytic logic are introduced for the determination of hydrodynamic moment and phase difference due to fluid motion in ART and verified through the test. The developed bench tester is believed to be effective and accurate for the verification of stabilization effect of ART taking into the consideration of the sway effect in the design stage.

• 한국전문물리치료학회지
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• 제29권4호
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• pp.274-281
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• 2022

Background: The range of motion (ROM) and balance ability of the ankle joint affect the stability of the ankle and prevent injuries or hurts from falling. In the clinical tests conducted recently, the floss band is widely used to enhance the range of joint motion and exercise performance, and there are many studies that have applied it to ankle joint increasing dorsi flexion (DF) angle. Objects: This study compared the effects on the range of ankle motion and static/dynamic balance ability of the ankle through three conditions (before floss band intervention, after floss band intervention, and after active exercise intervention) for adults. Methods: One intervention between floss band and active exercise was applied randomly and another intervention was applied the next day. After each intervention, the ROM of the ankle joints and the static balance was checked by measuring conducting one leg test. And the dynamic balance was checked by conducting a Y-balance test. Results: In the case of DF, the range of joint motion showed a significant increase after floss band intervention compared to before floss band intervention (p < 0.05). Static balance ability showed a significant increase after the intervention of floss band and active exercise compared to before the intervention of floss band (p < 0.05). The dynamic balance ability showed a significant increase after the intervention of the floss band compared to before intervention of the floss band and after active exercise intervention (p < 0.05). Conclusion: Based on these results, it was confirmed that the application of floss band to the ankle joint increases DF and improves the static and dynamic balance ability. Based on this fact, we propose the application of a floss band as an intervention method to improve the ROM of the ankle joint and improve the stability of the ankle in clinical field.

• 전기학회논문지
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• 제66권12호
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• pp.1852-1865
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• 2017

The vibration of the structures with restrained motion has long been observed in various engineering fields. When the motion of vibrating structure is restrained due to the adjacent objects, the frequencies and the mode shapes of the structure change and its vibration characteristics becomes unpredictable, in general. Although the importance of the study on this type of vibration model increases in many engineering areas, most studies conducted so far are limited to the theoretical study on dynamic responses of the structure with stops, including some experimental works. Specially, the study on the nonlinear phenomena due to the impact between the structure and the stops have been mainly performed theoretically. In the paper, both numerical analyses and experiments are conducted to study the chaotic vibration characteristics of the nonlinear motion and the dynamic response of a cantilevered beam which has restrained motion at the free end by the stops. Results are presented for various magnetic forces and gaps between the beam and stops. The conclusions are as follows : Firstly, Numerical simulation results have a good agreement with experimental ones. Secondly, the effect of higher modes of beams are increased with increasing magnitude of exciting force, and displacement and velocity curves become more complicated shapes. Thirdly, nonlinear characteristics tend to appear greatly with increasing magnitude of exciting force, and fractal dimension is increased.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권3호
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• pp.239-245
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• 2017

As a new technical approach, wave energy converter by using vertical motion of water in the multiple water chambers were developed to realize actual wave power generation as eco-environmental renewable energy. And practical use of wave energy converter was actually to require the following conditions: (1) setting up of the relevant device and its application to wave power generation in case that severe wave loading is avoided; (2) workability in installation and maintenance operations; (3) high energy conversion potential; and (4) low cost. In this system, neither the wall(s) of the chambers nor the energy conversion device(s) are exposed to the impulsive load due to water wave. Also since this system is profitable when set along the jetty or along a long floating body, installation and maintenance are done without difficulty and the cost is reduced. In this paper, we describe the system which consists of a float, a shaft connected with another shaft, a rack and pinion arrangement, a ratchet mechanism, and rotary type generator(s). Then, we present the dynamics model for evaluating the output electric power, and the results of numerical calculation including the effect of the phase shift of up/down motion of the water in the array of water chambers aligned along the direction of wave propagation.

• 한국해양공학회지
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• 제19권3호
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• pp.66-73
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• 2005

The sway motion control problem of a container hanging on the trolley is considered in this paper. In the container crane control problem, the main issue involves suppressing the residual swing motion of the container at the end of acceleration, during deceleration, or for an unexpected disturbance input. For this problem, in general, many trolley motion control strategies are introduced and applied. In this paper, we introduce and synthesize a swing motion control system, in which a small auxiliary mass is installed on the spreader. In this control system, the actuator reacting against the auxiliary mass applies inertial control forces to the container to reduce the swing motion in the desired manner. In many studies, the controllers used to suppress the vibration have been synthesized for the given mathematical model of plants. In many cases, the designers have not been able to utilize the degree of freedom to adjust the structural parameters for the control object. To overcome this problem, so called "Structure/Control Simultaneous Method" is used. From this, in this paper the simultaneous design method is used to achieve optimal system performance. And the experimental result shows that the proposed control strategy is useful, to the case of that the controlled system is exposed to the uncertainties and, robust to disturbances like wind.

• 척추신경추나의학회지
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• 제3권2호
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• pp.29-36
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• 2008

Object : The purpose of this study is to report the improvement of Tempormandibular Disorder patients who were treated by M.S.T(Motion Style Treatment). Methods : The clinical study was done on 3 cases of patients with tempormandibular disorder we checked the diameter between the maxilla and mandible with jaws fully opened, and also checked NRS score after the treatment of M.S.T(Motion Style Treatment) each day. Results & Conclusion : The diameter of the open mouth increased after the treatment of M.S.T(Motion Style Treatment), whereas NRS score decreased after the treatment of M.S.T(Motion Style Treatment). It is concluded that the M.S.T might be effective to the patient with tempormandibular disorder.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.26-28
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• 2007

The motion estimation is the most important technique in the image compression of the video standards. In the case of next generation standards in the video codec as H.264, a high compression-efficiency can be also obtained by using a motion compensation. To obtain the accurate motion search, a motion estimation should be achieved up to 1/2 pixel and 1/4 pixel uiuts. To do this, the computational complexity is increased although the image compression rate is increased. Therefore, in this paper, we propose the advanced sub-pixel block matching algorithm to reduce the computational complexity by using a statistical characteristics of SAD(Sum of Absolute Difference). Generally, the probability of the minimum SAD values is high when searching point is in the distance 1 from the reference point. Thus, we reduced the searching area and then we can overcome the computational complexity problem. The main concept of proposed algorithm, which based on TSS(Three Step Search) method, first we find three minimum SAD points which is in integer distance unit, and then, in second step, the optimal point is in 1/2 pixel unit either between the most minimum SAD value point and the second minimum SAD point or between the most minimum SAD value point and the third minimum SAD point In third step, after finding the smallest SAD value between two SAD values on 1/2 pixel unit, the final optimized point is between the most minimum SAD value and the result value of the third step, in 1/2 pixel unit i.e., 1/4 pixel unit in totally. The conventional TSS method needs an eight.. search points in the sub-pixel steps in 1/2 pixel unit and also an eight search points in 1/4 pixel, to detect the optimal point. However, in proposed algorithm, only total five search points are needed. In the result. 23 % improvement of processing speed is obtained.