• Journal of the Chungcheong Mathematical Society
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• v.31 no.2
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• pp.199-230
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• 2018

In this paper, we introduce the general form of a viginti functional equation. Then, we find the general solution and study the generalized Ulam-Hyers stability of such functional equation in multi-Banach spaces by using fixed point technique. Also, we indicate an example for non-stability case regarding to this new functional equation.

• Journal of applied mathematics & informatics
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• v.31 no.3_4
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• pp.577-594
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• 2013

In this paper, we study the global stability and the existence of almost periodic solution of high-order Hopfield neural networks with distributed delays of neutral type. Some sufficient conditions are obtained for the existence, uniqueness and global exponential stability of almost periodic solution by employing fixed point theorem and differential inequality techniques. An example is given to show the effectiveness of the proposed method and results.

• Journal of applied mathematics & informatics
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• v.8 no.2
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• pp.561-567
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• 2001

In this paper, we investigate the Hyers-Ulam-Rassias stability of a quadratic functional equation f(x+y+z)+f(x-y)+f(y-z)+f(x-z) = 3f(x)+3f(y)+3f(z) and prove the Hyers-Ulam stability of the equation on bounded domains.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.1127-1136
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• 1993

A mathematical model has been developed for the simulation of static stability of agricultural tractors. The model was based on Reichmann's model but modified to improve its shortcomings for practical applications. Two examples of model simulation were presented and showed its usefulness in evaluating the control and stability loss boundaries.

• Journal of the Korean Mathematical Society
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• v.48 no.2
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• pp.223-240
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• 2011

In this paper, the problem on periodic solutions of the bidirectional associative memory neural networks with both periodic coefficients and periodic time-varying delays is discussed. By using degree theory, inequality technique and Lyapunov functional, we establish the existence, uniqueness, and global asymptotic stability of a periodic solution. The obtained results of stability are less restrictive than previously known criteria, and the hypotheses for the boundedness and monotonicity on the activation functions are removed.

• Bulletin of the Korean Mathematical Society
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• v.38 no.2
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• pp.325-336
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• 2001

In this paper, we investigate the generalized Hyers-Ulam-Rassias stability of a quadratic function equation f(x+y+z)+f(x-y)+f(y-z)+f(z-x)=3f(x)+3f(y)+3f(z) and prove the Hyers-Ulam-Rassias stability of the equation on bounded domain.

• Journal of the Korean Mathematical Society
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• v.46 no.6
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• pp.1193-1206
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• 2009

C. Guenther studied the stability of DeTurck flows by using maximal regularity theory and center manifolds, but these arguments can not solve the stability of Ricci flows because the Ricci flow equation is not strictly parabolic. Recognizing this deficiency, the present paper considers and obtains the stability of Ricci flows, and of quasi-Ricci flows in view of some Killing conditions.

• Bulletin of the Korean Mathematical Society
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• v.50 no.5
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• pp.1555-1565
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• 2013

In this paper, some new generalized discrete Halanay inequalities are established. On the basis of these new established inequalities, we obtain the attracting set and the global asymptotic stability of the nonlinear discrete systems. Our results established here extend the main results in [R. P. Agarwal, Y. H. Kim, and S. K. Sen, New discrete Halanay inequalities: stability of difference equations, Commun. Appl. Anal. 12 (2008), no. 1, 83-90] and [S. Udpin and P. Niamsup, New discrete type inequalities and global stability of nonlinear difference equations, Appl. Math. Lett. 22 (2009), no. 6, 856-859].

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.399-402
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• 1988

In this paper, the relationship between stability and gain band-width product (GB) is clear ed by evaluating the feedback gain in the buck-boost switching regulator. Especially, considering the effect of the right-half-plane pole on the stability, we found available region of GB on the stability with the one pole compensation for the feedback circuit.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.369-372
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• 1994

In this paper, the robust stability of characteristic polynomials with respect to real parameter variations is investigated through a new functional approach. Specifically there is no restriction on the interrelationship between coefficients of the polynomials. This allows one to treat the robust stability problems alike without distinction as to continuous or discrete time systems. Necessary condition and sufficient condition for the robust stability are shown and some examples extracted from two-link planar manipulator are provided.