• Earthquakes and Structures
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• v.7 no.6
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• pp.1283-1301
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• 2014

Ground motion modification is extensively used in seismic design of civil infrastructure, especially where few or no recorded ground motions representative of the design scenario are available. A site in Los Angeles, California is used as a study site and 28 ground motions consistent with the design earthquake scenario are selected. The suite of 28 ground motions is scaled and modified in the time domain (TD) and frequency domain (FD) before being used as input to a bilinear SDOF system. The median structural responses to the suites of scaled, TD-modified, and FD-modified motions, along with ratios of he modified-to-scaled responses, are investigated for SDOF systems with different periods, strength ratios, and post-yield stiffness ratios. Overall, little difference (less than 20%) is observed in the peak structural accelerations, velocities, and displacements; displacement ductility; and absolute accelerations caused by the TD-modified and FD-modified motions when compared to the responses caused by the scaled motions. The energy absorbed by the system when the modified motions are used as input is more than 20% greater than when scaled motions are used as input. The observed trends in the structural response are predominantly the result of changes in the ground motion characteristics caused by modification.

• Science of Emotion and Sensibility
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• v.5 no.1
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• pp.33-48
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• 2002

This research aimed to (1) study the possibility of DMDI (i.e. ; digitalwear based on motion-detective input technology) as apparel product in young market, (2) to develop appropriate design of DMDI. In part I of this research, a deth-interview method developed on the assumption of design ethnography, and domain analysis were applied to analyze the consumers'latent demands and needs related to DMDI. Based on the result of analysis, the seven feasible applications and six design directions for DMDI were suggested.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.12
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• pp.118-123
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• 2015

The study of input and output characteristics in dynamic motion control is important indicator of the performance of mechanical equipment and is the factors to be considered during commissioning and maintenance of machinery or equipment, and project planning. The Analysis on dynamical characteristic of the input/output of the automation solution that used for motion control in machinery, is represented the control performance of device and including controller which connected at automation network by considering period of the frequency as applied load. This paper was constructed the simulator of B & R Powerlink to be widely used for motion control in the machine and showed the dynamic system characteristics by analysing the period.

• Journal of the Earthquake Engineering Society of Korea
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• v.25 no.6
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• pp.233-240
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• 2021

The stochastic method is applied to simulate strong ground motions at seismic stations of seven metropolises in South Korea, creating an earthquake scenario based on the causative fault of the 2016 Gyeongju earthquake. Input parameters are established according to what has been revealed so far for the causative fault of the Gyeongju earthquake, while the ratio of differences in response spectra between observed and simulated strong ground motions is assumed to be an adjustment factor. The calculations confirm the applicability and reproducibility of strong ground motion simulations based on the relatively small bias in response spectra between observed and simulated strong ground motions. Based on this result, strong ground motions by a scenario earthquake on the causative fault of the Gyeongju earthquake with moment magnitude 6.5 are simulated, assuming that the ratios of its fault length to width are 2:1, 3:1, and 4:1. The results are similar to those of the empirical Green's function method. Although actual site response factors of seismic stations should be supplemented later, the simulated strong ground motions can be used as input data for developing ground motion prediction equations and input data for calculating the design response spectra of major facilities in South Korea.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.8
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• pp.2480-2490
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• 1996

This paper presents a new type of hydraulic servo chllinder which is characterized by its simple construction and an ubtegrated feedback mechanism. Piston position of the cylinder is controlled by eletrical input and mechamical feedback deduced from its own structure. Hydraulic pressure in each cylinder room is controlled by a poppet valve. The poppet is activated by a solenoid and is linked to the piston. Solenoid input current pulls up the poppet, which results in pressure drop and thus piston motion. The piston motion generates pull down force on the poppet by the linkage and the motion stops at equilibrium. In that way the piston position is controlled by an expernal input current. Characteristics of the servo cylinder is verified by stability analysis, tranient vehavior and steady state positing for step input. Design parameter analyses have been executed by derivation of analytical approximate solutions and by computer simulations. A prototype hydraulic servo cylinder is developed and tested. The experimental results show successful function of the servo cylinder and consistency with the theoritical results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.462-465
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• 1995

In this research a 2-dimensional motion producer based on two linear motors was developed. When the tester provides some motion through the level attached to the upper moving part of the motion producer, it provides the arbitrary intertia, damping and stiffness characteristics without actual change in physical structure of the motion producer. That is, the active impedance is implemented by controlling input currents supplied to the linear motors. A PID controller with feedforward loop was used to control the currents and pre-processing of input velocity and accleration singals from the encoder and the current singnal from the motor driver circuit are conducted to improve the performance.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.3
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• pp.158-164
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• 2000

In recent year, desire and request fer micro automation are growing rapidly covering the whole range of the industry. This has been caused mainly by request of more accurate manufacturing process due to a higher density of integrated circuits in semiconductor industry. This paper presents a six d.o.f fine motion stage using magnetic levitation technique, which is one of actuating techniques that have the potential for achieving such a micro motion. There is no limit in motion resolution theoretically that the magnetically levitated part over a fixed stator can realize. In addition, it Is possible to manipulate the position and the force of the moving part at the same time. Then, the magnetic levitation technique is chosen into the actuating method. However, we discuss issues of design, kinematics, dynamics, and control of the proposed system. And a few experimental results fur step input are given.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.7
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• pp.28-37
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• 1997

In this paper, we designed a motion estimator for MPEG-2 video coder using VHDL. Motion estimation is indispensable for encoding MPEG 2 video. Motion estimation takes over 50% computation power of video encoding 37 frames per second and is suitable for real-time processing. The number of data accesses for computation is fewer than 2 times compared with that of old one. This makes slower memory module available. We minimize input pins to migrate input data through PEs. This processor can compute various motio estimation modes at one calculation that is supported by MPEG-2 video standard. Also independent control architecture makes this processor a single processor or a sub module in amultimedia chip.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1203-1204
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• 2008

In this paper, a new stereo object tracking system using the disparity motion vector is proposed. In the proposed method, the time-sequential disparity motion vector can be estimated from the disparity vectors which are extracted from the sequence of the stereo input image pair and then using these disparity motion vectors, the area where the target object is located and its location coordinate are detected from the input stereo image. Basing on this location data of the target object, the pan/tilt embedded in the stereo camera system can be controlled and as a result, 3D tracking of the target object can be possible.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.1
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• pp.82-89
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• 2003

A robust motion control method is proposed fur the point-to-point position control of a XY positioning system which consists of a base cart, elastic ben and moving mass. The horizontal motion controller consists of the feedforward controller to suppress the single mode vibration of the elastic beam and the feedback controller to get the high-accuracy positioning performance of the base cart. Input preshaping vibration suppression method based on system modeling with analytic frequency equation is proposed and integrated into the robust internal-loop compensator(RIC) to increase the robustness of the whole closed-loop system The vertical motion controller is proposed based on the dual RIC structure. Through experiments, it is shown that the proposed method can stabilize the system and suppress the vibration in the presence of uncertainties and disturbances.