• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.261-264
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• 1997

A single action press robot, which consists of a driving unit, rotator, up-down feed base and feed bar, is developed and applied for the press automation. The driving unit is made up with a face cam and blade cam, which have a phase angle. The feeding system consists of a double speed-up apparatus and linear motion guides, and has a fast motion characteristics. A horizontal feeding speed of the feed bar is increased twice by the double speed-up apparatus. The driving mechanism could be simplified due to the speed-up of the feeding unit.

• Journal of Broadcast Engineering
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• v.12 no.3
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• pp.289-292
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• 2007

A background initialization algorithm based on the spatiotemporal similarity measure in a motion tracking system is proposed. From the accumulated difference between the base frame and the other frames in a subinterval, the regions affected by moving objects are located. The median is applied over the subsequence in the subinterval in which co-located regions share the similarity. The outputs from each subinterval are filtered by second stage median filter. The proposed method showed good results even in the busy and crowded sequences where the real background does not exit.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.11a
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• pp.47-52
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• 2002

가상공간에서 탑승자에게 운동감을 제공하기 위해서 수많은 형태의 모션 시뮬레이터가 개발되어 왔다. 하지만 이러한 형태의 시뮬레이터들은 그 고유한 형태에 의해 정해진 동역학과 워시아웃 알고리즘을 거쳐야만 정밀한 시뮬레이터가 될 수 있다. 본 논문은 기존의 좁은 시야공간에서의 시뮬레이터가 아닌 넓은 시야를 제시하고, 모션 베이스와 독립적으로 운영되는 영상 제시기를 이용하여 탑승자에게 운동감을 제공하는 분리형 시뮬레이터를 대상으로 하여 영상과 모션을 동기화시켜서 제시하는 방법에 대해 논의하고자 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.191-194
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• 2002

In optical pick-up, optical components such as objective lens, collimator, mirror, laser diode and photo diode are mounted on the pick-up base. These components must keep their original position during operation for proper transmittance of information from laser diode to optical disk and back to photo diode. However, micro thermal deformation of pick-up base which is induced by thermal environment during operation can deteriorate the performance of optical pick-up. Therefore, it is important to measure and analyze the thermal deformation behavior of pick-up base under thermal environment. In the present study, a measurement system using holographic interferometry was designed to measure micro thermal deformation of pick up base. The measurement system was verified by using the deformation of cantilever with prescribed motion actuated by PZT with 1 nm resolution. Interferometric measurement was compared quantitatively with that induced by PZT actuator. Finally, micro thermal deformation of pick-up base under actual thermal environment was measured using the present holographic interferometry and the results were analysed.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2120-2123
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• 2003

This paper presents the moving object detection and tracking algorithm using edge information base on human perceptual system The human visual system recognizes shapes and objects easily and rapidly. It's believed that perceptual organization plays on important role in human perception. It presents edge model(GCS) base on extracted feature by perceptual organization principal and extract edge information by definition of the edge model. Through such human perception system I have introduced the technique in which the computers would recognize the moving object from the edge information just like humans would recognize the moving object precisely.

• Structural Engineering and Mechanics
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• v.34 no.5
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• pp.663-666
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• 2010

The spectral content of ground displacement of the 10 largest last California earthquakes is studied. Specifically, the power spectral density function of the critical horizontal-component record of the closest-to-epicenter station is analyzed in each case. The results permit to state that horizontal ground displacement is a narrow-band process. This fact was previously noticed while trying to solve the large-base-displacement problem in isolated structures and it was fundamental in the solution of this issue; however, these preliminary results were limited in number to enable a statement like the foregoing one. Thus, the broader results presented herein were necessary.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.6
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• pp.408-414
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• 2004

In this paper, a disturbance observer based sliding mode control is proposed to attenuate disturbance responses in an active magnetic bearing system, which is subject to base motion. An algorithm which decouples disturbance observation dynamics from sliding mode dynamics is suggested. This algorithm preserves the robustness of the sliding mode control and satisfies reachability condition in the presence of external disturbance and parameter uncertainties. Along with experimental results, it is shown that the proposed control is effective in disturbance rejection without any additive disturbance measurement.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.6
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• pp.879-889
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• 2003

This research deals with the nonlinearities of rocking vibration associated with impact and sliding on the rocking behavior of rigid block under two dimensional sinusoidal excitation which has different frequencies in two excitation direction. The varied excitation direction influences not only the rocking response but also the sliding motion and the rocking response shape. Chaotic responses are observed in wider excitation amplitude region, when the frequencies in each excitation direction are different. The complex behavior of chaotic response, in the phase space, is related with the trajectory of base excitation and sliding motion.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.619-624
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• 2007

Spectral element method (SEM) is introduced for the fully coupled structural dynamic problems, In this paper, the beam with passive constrained layered damping (PCLD) treatments is considered as a representative problems. The beam consists of a viscoelastic layer that is sandwiched between the base beam structure and an elastic layer, The fully coupled equations of motion for a PCLD beam are derived, The equations of motion are derived first by using Hamilton's principle, From this equations of motion, the spectral element is formulated for the vibration analysis by use of the SEM, As an illustrative example, a cantilevered beam is considered. It is shown that, as the thickness of VEM layer vanishes, the results become a simple layer beam's that.

• Journal of KSNVE
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• v.2 no.1
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• pp.49-59
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• 1992

The motion analysis of a translation device driven by a piezoelectric actuator is performed to identify the mechanics of impact drive mechanism and to find the maximum speed waveform. The translation device is modeled as a semidefinite two-degree-of-freedom system. The motion analysis includes effects of friction force between moving mass and contact surface, dynamics of voltage amplifier and piezoelectric elements, and hysteresis of piezoelectric actuator. Base on the model, simulation studies are carried out and then compared with experimental results. It is found that the error between moving distances obtained by analysis and experiment is less than 15% and that the actual motion of moving mass is well predicted by the analytical work, finally, precision positioning experiments are carried out by using a proximity sensor as a feedback sensor. Position control of moving mass is initiated by the maximum speed waveform and finely tuned by the scaled down waveform so that accurate positioning is accomplished within the resolution of the sensor.