• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.4
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• pp.429-441
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• 2002

This paper concerns extracting 3D motion information from a 3D input device in real time focused to enabling effective human-computer interaction. In particular, we develop a novel algorithm for extracting 6 degrees-of-freedom motion information from a 3D input device by employing an epipolar geometry of stereo camera, color, motion, and structure information, free from requiring the aid of camera calibration object. To extract 3D motion, we first determine the epipolar geometry of stereo camera by computing the perspective projection matrix and perspective distortion matrix. We then incorporate the proposed Motion Adaptive Weighted Unmatched Pixel Count algorithm performing color transformation, unmatched pixel counting, discrete Kalman filtering, and principal component analysis. The extracted 3D motion information can be applied to controlling virtual objects or aiding the navigation device that controls the viewpoint of a user in virtual reality setting. Since the stereo vision-based 3D input device is wireless, it provides users with a means for more natural and efficient interface, thus effectively realizing a feeling of immersion.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.195-200
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• 2008

This paper presents motion control of the Inchworm composed of the piezoelectric actuators and mechanical elements. Piezoelectric actuator shows nonlinear response characteristics including hysteresis due to the ferroelectric characteristics. This paper proposes feedback control scheme to improve the ability of tracking response to complex input signal and suppress the phenomenon of hysteresis using the sliding mode control technique with the integrator. The sliding mode control system has the limit to minimize both the settle time and overshoot. For making up this limit, this paper also suggests input shaping technique suitable to the inchworm control system.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.12
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• pp.1033-1041
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• 2003

A new visual tracking scheme is proposed for a mobile robot that tracks a moving object in 3D space in real time. Visual tracking is to control a mobile robot to keep a moving target at the center of input image at all time. We made it possible by simplifying the relationship between the 2D image frame captured by a single camera and the 3D workspace frame. To precisely calculate the input vector (orientation and distance) of the mobile robot, the speed vector of the target is determined by eliminating the speed component caused by the camera motion from the speed vector appeared in the input image. The problem of temporary disappearance of the target form the input image is solved by selecting the searching area based on the linear prediction of target motion. The experimental results have shown that the proposed scheme can make a mobile robot successfully follow a moving target in real time.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.445-449
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• 1989

Achievement of a straight line motion in the Cartesian space has a matter of great importance. Minimization of task execution time with linear interpolation in the joint space, accomplishing of a approximation of straight line motion in the Cartesian coordinate is considered as the prespecified task. Such determination yields minimum time joint-trajectory subject to input torque constraints. The applications of these results for joint-trajectory planning of a two-link manipulator with revolute joints are demonstrated by computer simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.2
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• pp.313-325
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• 1996

This paper presents a new architecture for full-search block-matching motion estimation. The architecture is based on linear systolic arrays. High speed operation is obtained by feeding reference data, search data, and control signals into the linear systolic array in a pipelined fashion. Input data are fed into the linear systolic array at a half of the processor speed, reducing the required data bandwidth to half. The proposed architecture has a good scalability with respect to the number of processors and input bandwidth when the size of reference block and search range change.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.312-319
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• 1998

The effect of noise on the input motion for the seismic test of structures using shaking table was studied. Table motions usually contain high frequency contents which influence the PGA of input motions. It was shown that the noise influenced PGA much with minor changes in high frequency contents. The Butterworth bandpass filter can be effectively used. The adequacy of the table motion should be judged based on both the frequency contents and the PGA.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.5
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• pp.753-761
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• 1987

Approximation of a Cartesian straight line motion with linear interpolation in the joint space has many desirable advantages and applications. But inappropriate determination of the corresponding subtravelling and transition times makes such joint-trajectories violate the input torque/force constraints. An approach that can overcome this difficult and yield the joint trajectories utilizing the allowable maximum input torque/force is established in this paper. The effectiveness of these results is demonstrated by using a three-joint revolute manipulator.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.3
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• pp.109-116
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• 2003

In this paper. we Propose an UXGA class LCD controller for controlling the LCD panel. The proposed controller supports the full screen display using GCD between input and output resolutions. The proposed LCD controller includes the motion detector based on median filter which can detect the motion of input image for the enhancement of a image quality. Also, it divides the motion into 3 stages such as still, semi-moving and moving, and uses the different interpolation algorithms according to the degree of motion. In order to evaluate the performance of the proposed interpolation algorithm, we use PSNR method and compare the conventional algorithm by using computer simulation. For the proposed motion detection algorithm, we use a visual verification and the estimation of pixel changes. The proposed LCD controller has been designed and verified by VHDL. It has been synthesized using Xilinx VirtexE FPGA.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.10
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• pp.1110-1118
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• 2012

In this study, for reducing the residual vibration in high speed motion control stage, an improved 5th order polynomial motion profile was developed. When a stage is moving, the current through the motor coils has the same profile of input motion profile of acceleration, therefore the characteristics of the acceleration input profile directly affect on the performance of the amplifier that includes the current control loop. Commonly low cost amplifier and motor has a narrow current control bandwidth, therefore the proposed algorithm was designed based on this practical constraint. Simulation and experimental results showed that the proposed algorithm clearly has low residual vibration characteristics than conventional 5th order polynomial motion profile on the same drive condition.

• Structural Engineering and Mechanics
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• v.53 no.5
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• pp.957-979
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• 2015

The present paper investigates the influence of the orientation of the ground-motion reference axes, the seismic incident angle and the seismic intensity level on the inelastic response of asymmetric reinforced concrete buildings. A single storey asymmetric building is analyzed by nonlinear dynamic analyses under twenty bi-directional ground motions. The analyses are performed for many angles of incidence and four seismic intensity levels. Moreover three different pairs of the horizontal accelerograms corresponding to the input seismic motion are considered: a) the recorded accelerograms, b) the corresponding uncorrelated accelerograms, and c) the completely correlated accelerograms. The nonlinear response is evaluated by the overall structural damage index. The results of this study demonstrate that the inelastic seismic response depends on the orientation of the ground-motion reference axes, since the three individual pairs of accelerograms corresponding to the same ground motion (recorded, uncorrelated and completely correlated) can cause different structural damage level for the same incident angle. Furthermore, the use of the recorded accelerograms as seismic input does not always lead to the critical case of study. It is also shown that there is not a particular seismic incident angle or range of angles that leads to the maximum values of damage index regardless of the seismic intensity level or the ground-motion reference axes.