• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.1
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• pp.105-113
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• 1998

A new image processor is implemented for high-speed digital copiers and facsimiles. The imgage processor performs CCD and CIS interface, pre-processing, enlargement andreduction of gray level image, and various halftoning algorithms. Implemented halftoning algorithms are simple thresholding, fuzzy based mixed mode thresholding, dithering, and edge enhanced error diffusion. The result of binarization is transferred to a printer with serial or paralel output ports. Line by line pipelined data prodessing architecture is employed with time sharing access of the external memory. In receiving mode, it converts the resolution of received binary image for compatibility with conventional facsimile. In copy mode, a line of A3 paper with 400 dpi is processed with in 2.5 ms. The prototype of image processor was implemented usig Laser Programmable Gate Array (LPGA) with 0.8.mu.m technology.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.12
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• pp.31-38
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• 2003

In this paper, we proposed a new structural AGC(Automatic Gain Control) circuit with extremely short settling time using high speed operation characteristics of a clipper. We investigated its operation characteristics in analysis. We also designed a burst-mode preamplifier for 1.25Gbps EPON systems using commercial foundry and investigated its characteristics by comparing the results of the designed and those of the analyzed. The characteristics of the designed circuit are in good agreement with those of the analyzed. As a result, it is shown that it is possible to realize extremely short settling time of under 1㎱.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.323-329
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• 1994

In the systems such as walking robots or high speed operating manipulators, the effect of nonlinear terms is important and can not be neglected. Therefore the application of linear control law to such systems is inadequate. Moreover, because of the mathematical modeling errors the systems may become unstable. In this study, we designed a nonlinear controller with sliding mode scheme, which is robust to the modeling errors and applied this control algorithm to the 5 DOF biped robot system. Throught the computer simulations, we examined walking characteris and walking stability of the 5 DOF biped robot system.

• Journal of KSNVE
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• v.7 no.2
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• pp.261-272
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• 1997

Recently washing machines are to be in lower vibration and lower sound because of better environment. Vibration problems in washing machines occur in both washing mode and spinning mode, but vibration in spinning mode becomes main problem because of its high rotating speed and continuity. Vibration while spinning is mainly due to rigid body motion of total washing system which includes suspending rods, washing bath, spinning bath, and gear sets. In this study, some researches were done in order to analyze the rigid body motion of washing system and flexible vibration of spinning bath. A basic mathematical model was established, and the effect of position of salt water and shape change of salt water case were considered. And the effect of lengths of suspending rods, attaching angles, vertical and horizontal position, stiffness of spring on the change of vibration were also considered. To identify the effect of salt water on vibration, some measurements were done. When salt water was positioned at upper part, the effect was most and this coincides with the tendency of simulation.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.773-776
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• 1995

Sliding Mode Controller is largely used to control holy nonlinear system such as robot manipulator. This paper simulate the SCARA robot with sliding mode control algorithm and its applied form with saturation term to reduce chattering. In addition, hardware system using DSP board which operates with high speed is constructed.

• Journal of Sensor Science and Technology
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• v.24 no.2
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• pp.93-95
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• 2015

We present an optical detection method for the fundamental vibrational mode of a tuning fork crystal oscillator in air. A focused He/Ne laser beam is directed onto the edge of one vibrating tine of the tuning fork; its vibrating motion chops the incoming laser beam and modulates the intensity. The beam with modulated intensity is then detected and converted to an electrical signal by a high-speed photo-detector. This electrical signal is a sinusoid at the resonant frequency of the tuning fork vibration, which is 32.76 kHz. Our scheme is robust enough that the sinusoidal signal is detectable at up to $40^{\circ}$ of rotation of the tuning fork.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.861-865
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• 2001

Generally the noise and vibration characteristics of 4WD vehicle is closely related to the characteristics of driveline such as bending mode, torsional mode, unbalance and nonuniformity of propeller shaft. In this paper the 4WD vehicle which has body vibration problem in high speed driving condition was tested. The sources of the body vibration and its transfer path are investigated by experimental approach. According to the experimental assessment, the body vibration is caused by the nonuniformity of joint of propeller shaft. And this paper presents a kinematic model of a vehicle driveline for the optimization of a driveline characteristics. Finally the optimized result of the drive line has been verified through the experiment.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.367-370
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• 2011

A high-resolution numerical study is carried out to investigate the transient process of the combustion and the shock-train developments in an ethylene-fueled direct-connect dual-mode scramjet combustor. Air-throttling is then applied at the expansion part of the combustor to provide mass addition to block the flow to subsonic speed, hence to enhance the fuel-air mixing and ignition. Present simulation shows the detailed results for the better understanding of transient processes of the operation regimes in the dual-mode scramjet combustor.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.806-807
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• 2011

This paper presents a new sensorless controller used with both the classical sliding mode observer(SMO) and the rate of current change in order to a reduced torque ripple for switched reluctance motor (SRM) sensorless drives. The new sensorless scheme consists of a sliding mode observer (SMO)-based position sensorless approach for high speeds along with a low-resolution discrete the rate of current change for low speeds and standstill. The new position estimation resets between the SMO and the low-resolution of current change according to the speed sign and the position error difference between the SMO and the low-resolution rate of current change. The simulation results show the robustness of this new high performance sensorless control approach with the hybrid sensorless control topology.

• The Transactions of the Korean Institute of Power Electronics
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• v.2 no.3
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• pp.37-43
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• 1997

Microstepping control of two phase hybrid step motors provides high step resolution as well as smoothness of operation at low speed, and removes most of the resonance phenomena which is undesirable. This paper focuses on the development of a microstepping driver with enhanced performance. The developed microstepping driver can divide one step(l.8 degree) into 128 microsteps and supports current saving mode to remove the thermal problems which results from long time operation.