• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.69-72
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• 2003

In this paper new control strategy of series resonant converter system for control power supply is suggested. Frequency controlled series resonant converter system is robust to load variations because it is POSR(parallel output series resonant) type. And it provides stable output voltage by changing switching frequency to input voltage variations. Firstly, operation analysis about suggested series resonant converter system was carried. Then simulations using ACSL(Advanced Continuous Simulation Language) and experiments to actual system were carried to prove characteristics of suggested system.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.139-144
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• 2000

Recently, a homogeneous fuzzy time series model was proposed by means of defining some new operations on fuzzy numbers. In this paper, we consider expanding the results to the nonhomogeneous fuzzy time series and the general fuzzy time series using Tw, the weakest t-norm, based algebraic fuzzy operations.

• Proceedings of the Korean Statistical Society Conference
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• 2000.11a
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• pp.267-269
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• 2000

Using the fuzzified coefficients, ARMA processes can be extended to fuzzy time series model. In this paper, the estimation of parameters in the fuzzy time series model with asymmetric triangular fuzzy coefficients is studied. Nonlinear programming is applied to get solutions of parameters.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.651-656
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• 2000

This paper describes the optimal sizing of each component using computer simulation and presents the efficient operating scheme of series HEV using hardware simulator the equivalent system. As the sizing method of components have been experimental and empirical it is needed to spend much time and development cost. however the results of computer simulation will set the optimal sizing of components in short time. There are two type of driving control power-tracking mode and load-levelling mode in series HEV. This paper presents that series HEV be operated in the load-levelling mode which is more efficient that power-tracking mode.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.735-738
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• 2000

In this paper we propose a series active power filter and a simple calculation method acquiring the reference voltage. A series active power filter is suitable to suppress harmonics produced by voltage type harmonic source such as a diode rectifier with filter capacitor on the DC side The proposed series active power filter system is applied to 3-phase 3-wire power system including the voltage type harmonic source. Experimental result obtained from a laboratory model are shown to verify the viability and effectiveness of the proposed system.

• Bulletin of the Korean Mathematical Society
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• v.53 no.3
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• pp.699-709
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• 2016

Our paper is devoted to the study of certain diophantine equations on the ring of polynomials over a finite field, which are intimately related to algebraic formal power series which have partial quotients of unbounded degree in their continued fraction expansion. In particular it is shown that there are Pisot formal power series with degree greater than 2, having infinitely many large partial quotients in their simple continued fraction expansions. This generalizes an earlier result of Baum and Sweet for algebraic formal power series.

• Communications of the Korean Mathematical Society
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• v.14 no.3
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• pp.641-647
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• 1999

The object of this note is to give sums of certain families of series which are initiated from their special cases considered here. Pelevant connections of the series identities presented here with those given elsewhere are also pointed out.

• Communications of the Korean Mathematical Society
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• v.13 no.2
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• pp.435-443
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• 1998

Some mathematical constants have been used in evaluating series involving the Zeta function, the origin of which can be traced back to an over two centries old theorem of Christian Goldbach. We show some of the series involving the Zeta function can be evaluated in terms of the Catalan's constant by using the theory of the double Gamma function.

• Bulletin of the Korean Mathematical Society
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• v.46 no.6
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• pp.1201-1211
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• 2009

The aim of this research paper is to establish generalizations of classical Dixon's theorem for the series $_3F_2$, a result due to Bailey involving product of generalized hypergeometric series and certain very interesting summations due to Ramanujan. The results are derived with the help of generalized Kummer's summation theorem for the series $_2F_1$ obtained earlier by Lavoie, Grondin, and Rathie.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.423-426
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• 1999

This paper describes a driving scheme of the series hybrid electric vehicle that we have developed. Both series HEV and parallel HEV are well known. We chose series HEV because it provides good energy efficiency in urban driving and operates in all-electric mode in performance. And engine-Generator is driven at constant speed with constant load to maintain the low emission. And the battery supplies power during high-load and receive energy during low-load