• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.20 no.1
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• pp.1-15
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• 2016

The continuous analysis, such as smoothness and uniform convergence, for polynomials and polynomial-like functions using differential operators have been studied considerably, parallel to the study of discrete analysis for these functions, using difference operators. In this work, for the difference operator ${\nabla}_h$ with size h > 0, we verify that for an integer $m{\geq}0$ and a strictly decreasing sequence $h_n$ converging to zero, a continuous function f(x) satisfying $${\nabla}_{h_n}^{m+1}f(kh_n)=0,\text{ for every }n{\geq}1\text{ and }k{\in}{\mathbb{Z}}$$, turns to be a polynomial of degree ${\leq}m$. The proof used the polynomial convergence, and additionally, we investigated several conditions on convergence to polynomials.

• Journal of Power Electronics
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• v.9 no.6
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• pp.884-891
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• 2009

An address voltage stabilization circuit for the single-side driving (SSD) method for AC plasma display panels (PDP) is proposed. The single-side driving method, which eliminates a common sustaining driver, uses only two electrodes in a three electrode AC PDP structure. The high-impedance (Hi-Z) mode operation of the data drive ICs during the sustaining period is needed for surface gas-discharge without misfiring in the SSD method but it produces the problem that the address voltage increases up to the breakdown voltage. The proposed circuit based on a flyback converter can stabilize the address voltage under the breakdown voltage and provide better surface gas-discharge performance without any misfiring in the SSD scheme.

• Journal of the Korean Society of Industry Convergence
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• v.3 no.1
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• pp.3-8
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• 2000

This paper describes a development of self tuning scheme for PI and PO type fuzzy controllers. The output scaling factor(SF) is adjusted on-line by fuzzy rules according to the current trend of the controlled process. The rule-base for tuning the output SF is defined on error and change of error for the controlled variable using the most natural and unbiased membership functions. Simulation results demonstrate the better control performance can be achieved in comparison with Ziegler-Nichols(Z-N) PID controllers.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.449-454
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• 1994

This paper describes new PID control methods based on the fuzzy logic. PID gains are retuned after evaluating control performances of transient responses in terms of performance features. The retuning procedure is based on fuzzy rules and reasoning accumulated from the knowledge of experts on PID gain scheduling. For the case that the retuned PID gains result in worse CLDR (characteristics of load disturbance rejection) than the initial gains, an on-line tuning scheme of the set-point weighting parameter is, proposed. This is based on the fact that the set-point weighting method efficiently reduce either overshoot or undershoot without any degradation of CLDR. The set-point weighting parameter is adjusted at each sampling instant by the fuzzy rules and reasoning. As a result, better control performances were achived in comparison with die controllers tuned by the Z-N (Ziegler-Nichols) parameter tuning formula or by the fixed set-point weighting parameter.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1487-1490
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• 2006

One of the factors deteriorating PDP image quality is the nonlinearity and nonuniform of output luminance as a function of input gray level. A novel method using modified ADS driving scheme is proposed to decrease this nonlinearity. It optimizes the reset pulse and adjusts the subfields, makes the relation of output luminance and input gray level almost linear. This method can be applied to general commercial PDPs.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.488-493
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• 1989

In this paper, the structure of CMAC address mapping is first revisited, and the address hashing function and the random mapping is discussed in the conventional CMAC implementation. Then the effective size of CMAC memory is derived from the modulus property of the CMAC address vector, and a new hashing function for the effective memory mapping is proposed for a CMAC implementation with feasible memory size and no troublesome random mapping. Finally, the performance of the conventional CMAC learning algorithm and that of the proposed new CMAC scheme arc compared via simulations.

• Journal of the Optical Society of Korea
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• v.6 no.1
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• pp.5-12
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• 2002

A novel interrogation scheme to detect fine Bragg wavelength shift using a long period fiber grating pair with erbium-doped fiber inserted between the two gratings is reported. The technique is shown to feature high resolution and much more immunity to temperature perturbation compared to the conventioned Mach-Zehnder interferometer demodulation system. For quasi-static strain measurement, this approach provides high wavelength resolution of 0.05 pm that corresponds to 41.7 ne in strain and $3.8 $\times$ 10^{-3}$$^{\circ}C$ in temperature. This interrogation system is also employed in dynamic measurement to obtain the minimum detectable strain perturbation of ~ 8.76 ne/H $z^{{\frac}{1}{2}}$ at 100 Hz. Moreover, this interrogation system has prominent thermal stability. This thermal stability comes from the fact that two arms of the interferometer, the core and cladding in erbium-doped fiber, are exposed to nearly the same environment .

• Journal of Korean Society for Quality Management
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• v.24 no.3
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• pp.77-93
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• 1996

This paper is concerned with the International Standard ISO 2859-1 (1989), Sampling Plans Indexed by Acceptable Quality Level (AQL) for Lot-by-Lot Inspection, his standard is AQL type sampling scheme, and incorporates switching rules to move among normal, tightened, and reduced inspections. Sample size code letters and inspection levels of ISO 2859-1 are the same as those of other attributes standards MIL-STD-105D, ANSI Z1.4, and KS A 3109. But ISO 2859-1 has more simple switching rules than KS A 3109 has. The sampling procedures of the ISO 2859-1 are matched to the variables international standard ISO 3951 to enable us to move between them. Composite OC and ASN curves are given for AQL 2.5% and code letter F.

• Journal of the Korean Society for Precision Engineering
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• v.7 no.1
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• pp.63-73
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• 1990

Low cost automatic welding machine is developed for the purpose of welding process automation of automobile parts with two dimensional welding joints. Developed gantry type machine is equipped with X, Y and roll axis stepping motors, and dirive units units are designed by two phase on drive scheme using shift registers. Control system is constructed by single board microcomputer of Z80A CPU, and also it is equipped with parallel input output ports and counter-timer chips. Linear and circular interpolation of welding head movement is accomplished by employing software digital differential analyzers. It has been shown that contour error of develped system is withi ${\pm}1.0mm$, meaning that the machine is suitable for CO2 arc welding process of automoble parts and is expected it's application to industry.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.12
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• pp.1266-1272
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• 2011

For way-point tracking of an autonomous underwater vehicle, a state feedback controller was designed by using pole placement scheme in discrete time domain. In the controller, 4 state variables were used for regulating the depth of the vehicle in z direction, and 3 state variables, for steering the vehicle in xy plane. Assuming constant speed of AUV, we simplified the design of the way-point tracking system. The proposed controller was simulated by MATLAB/Simulink using 6 degree-of-freedom nonlinear model and its performance of way point tracking was shown to be fulfilled within 1 m, nevertheless the proposed controller is quite simple and easy to implement compared to sliding mode controller.