• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.11
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• pp.1077-1082
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• 2007

We present a micromechanical active amplifier, inspired from the principle of the outer hair cells in cochlea, amplifying both displacement and force. The present micromechanical active amplifier modulates the resonant carrier motion using the variable stiffness spring whose stiffness changes proportionally to the input motion. We design, fabricate, and characterize two types of the amplifiers A and B, each having the variable stiffness spring fur the maximum displacement gain and force gain, respectively. In the experimental study, the amplifier A shows the displacement gain of 5.62, which is 2.15 times larger than that of the amplifier 3. The amplifier B shows the force gain of 10.0, resulting in 1.26 times larger value compared to that of the amplifier A. We experimentally verify that the haircell-inspired micromechanical amplifiers are capable to amplify both displacement and force.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.11
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• pp.1182-1194
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• 2004

This paper addresses the application of an active magnetic bearing (AMB) system to levitate the elevation axis of an electro-optical sight mounted on a moving vehicle. In this type of system, it is desirable to retain the elevation axis in an air-gap between magnetic bearing stators while the vehicle is moving. To eliminate disturbance responses, a disturbance observer based sliding mode control is developed. This control can decouple disturbance observation dynamics from sliding mode dynamics and preserves the robustness of the sliding control. The sliding surfaces are designed in the consideration of scattering of received image. The proposed control is applied to a 2-DOF active magnetic bearing system subject to base motion. Along with experimental results, the feasibility of the proposed technique is illustrated.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.846-851
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• 2004

In this paper, a sliding mode control based on disturbance observer is proposed to attenuate disturbance responses in an active magnetic bearing system, which is subject to base motion. An algorithm for exactly decoupling the disturbance estimation dynamics from the sliding mode dynamics is developed. It is also shown that the proposed method preserves the robustness of the sliding mode and asymtotically achieves zero regulation error, in the presence of external disturbances and parametric uncertainties. The proposed control is applied to a 2-DOF active magnetic bearing system subject to base motion. The feasibility of the proposed technique is illustrated, and the results of an experimental demonstration are shown.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.857-860
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• 2000

In this letter, The proposed algorithm has processed the motion estimation and compensation only in the region which has the motion. By considering the temporal redundancies between the successive frames, the bit cost for representing the motion are reduced efficiently. The performance of them proposed technique show the superior result to the existing methods' in terms of both PSNR and coding cost.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.10
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• pp.1095-1102
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• 2014

In this paper, We proposed the approach of GPU and motion vector to analysis the Human activity in real-time surveillance system. The most important part, that is detect blob(human) in the foreground. We use to detect Adaptive Gaussian Mixture, Weighted subtraction image for salient motion and motion vector. And then, We use motion vector for human activity analysis. In this paper, the activities of human recognize and classified such as meta-classes like this {Active, Inactive}, {Position Moving, Fixed Moving}, {Walking, Running}. We created approximately 300 conditions for the simulation. As a result, We showed a high success rate about 86~98%. The results also showed that the high resolution experiment by the proposed GPU-based method was over 10 times faster than the cpu-based method.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1178-1183
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• 1990

A digital signal processor(DSP) is applied to realizing a compensator of control system of active magnetic bearings, to restrict a resonance caused by the first-order bending vibration of a flexible rotor, and to run the rotor beyond the critical speed. A full-order observer is applied to the translatory rotor-motion with the first-order vibration mode. A PID control is used for the conical motion. The rotor used in the experiments is symmetric, and an electromagnet and a displacement sensor are set in collocation.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.9 no.1
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• pp.89-101
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• 2014

Objectives : The purpose of this study is to report the effect of Korean medicine treatment combined with active release technique on supraspinatus tendon partial tear. Methods : Two patients with supraspinatus tendon partial tear were treated by Korean medicine treatment in combination with active release technique. Visual analog scale(VAS), range of motion(ROM) were used to measure changes during treatment. Results : After treatment, shoulder pain and limited range of motion were improved significantly. Conclusions : Korean medicine treatment in combination with active release technique is proved to be helpful to improve the symptoms of the supraspinatus tendon partial tear patients. And, further studies will be needed.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.16 no.2
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• pp.40-47
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• 2010

Purpose : To exam the effects of active ankle range of motion(ROM) exercise on sciatic nerve movement and provide the evidence that use it to patients with hypomobile sciatic nerve as a nerve mobilization technique. Methods : The subjects consist of 32 asymptomatic healthy adults(male; 15, female; 17) who have limited passive straight leg raising(PSLR) ranges below 70 degrees. First, examiner measures PSLR angles at three times. Then, subject was instructed perform the active ankle ROM exercise(dorsiflexion and plantarflextion) at limited angle. After each subject completed the active ankle ROM exercise, return the starting position and examiner measures the PSLR angles at three times again. Results : First, PSLR range was no significant differences between dominant and non-dominant leg(p >.05). Second, active ankle ROM exercise significantly increased PSLR range by mean of degrees(p <.05). Third, there was no learning effects among the measurement trials(p >.05). Conclusion : These data show that active ankle ROM exercise can mobilize the sciatic nerve. Therefore, it can be applied to patients with hypomobile sciatic nerve(sliding dysfunction) as a neural mobilization technique.

• Physical Therapy Korea
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• v.17 no.2
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• pp.43-50
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• 2010

The purpose of this study was to investigate the effects of Evjenth-Hamberg stretching on the active range of motion (ROM) of the hip joint and the pennation angle of the semitendinosus muscle. Eighty healthy adults participated in this study. The active ROM of the hip joint was measured by a goniometer and the pennation angle of the semitendinosus muscle was measured by ultrasonographic imaging (USI). Both ROM and pennation angle were recorded before and after the static stretching and the Evjenth-Hamberg stretching, respectively. Data were analyzed using paired t-lest and independent t-test at p<.05. The results were as follows: 1) The active ROM of the hip joint increased significantly after both stretching interventions compared with the baseline (p<.001). However, the active ROM of the hip joint increased significantly in Evjenth-Hamberg stretching compared with static stretching. 2) The pennation angle decreased significantly after both stretching interventions compared with the baseline (p<.001). However, the pennation angle decreased significantly in Evjenth-Hamberg stretching compared with static stretching. 3) Reliability data showed that there was a high consistency in USl measurements (ICC=.978). Our findings suggest that the Evjenth-Hamberg stretching was more effective than static stretching in increasing the active ROM of the hip joint and decreasing the pennation angle of the semitendinosus muscle.

• Progress in Superconductivity and Cryogenics
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• v.14 no.3
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• pp.60-64
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• 2012

In this paper, an investigation of a room temperature active magnetic regenerative refrigerator is carried out. Experimental apparatus includes two active magnetic regenerators containing 186 g of Gd spheres. Four E-type thermocouples are installed inside the Active magnetic regenerator(AMR) to observe the instantaneous temperature variation of AMR. Both warm and cold heat exchangers are designed for large temperature span. The cold heat exchanger, which separates the two AMRs, employs a copper tube with length of 80 mm and diameter of 6.35 mm. In order to minimize dead volume between the warm heat exchanger and AMRs, the warm heat exchangers are located close to the AMRs. The deionized water is used as a heat transfer fluid, and maximum 1.4 T magnetic field is supplied by Halbach array of permanent magnets. The AMR plate, which contains the warm and the cold heat exchangers and the AMRs, has reciprocating motion using a linear actuator and each AMR is alternatively magnetized and demagnetized by a Halbach array of permanent magnet. Since the gap of the Halbach array of permanent magnets is 25 mm and two warm heat exchangers have the motion through it, a compact printed circuit heat exchanger (PCHE) is used as a warm heat exchanger. A maximum no-load temperature span of 26.8 K and a maximum cooling power of 33 W are obtained from the fabricated Active Magnetic Regenerative Refrigerator (AMRR).