• Phonetics and Speech Sciences
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• v.5 no.3
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• pp.95-101
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• 2013

Aging is related to anatomical and physiological changes in respiratory and phonation organs. These changes influence articulation which leads to inaccurate speech and slow articulatory diadochokinesis(DDK). DDK indicates the range, rate, regularity, accuracy, and agility of articulation that reflect motor speech function. The purpose of this study is to investigate the rates and regularities of DDK in healthy Korean elderly through passive acoustic analysis (Praat). Thirty subjects between the ages of 65 and 94 participated in this study. Rate was observed for 5 seconds, while regularity was calculated based on the standard deviation on the following: 1) syllable duration of each task; 2) gap duration between syllables. Then, simple regression analysis was conducted in order to examine the effect of age on performance. The result showed that the slow rate was not a significant factor in terms of advancing age. Furthermore, regularity indicated a significant difference in the following: 1) /pʌ/, /kʌ/ and /pʌtʌkʌ/ in syllable duration; 2) /kʌ/ duration in the gap between syllables. In conclusion, articulatory coordination is reduced with the onset of aging. In particular, /kʌ/ would be a sensitive task for articulatory coordination.

• Journal of the Korean Mathematical Society
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• v.37 no.6
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• pp.957-975
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• 2000

We find a regularity criterion for the Ostwald-de Waele models like Serrin's condition to the Navier-Stokes equations. Moreover, we show short time existence and estimate the Hausdorff dimension of the set of singular times for the weak solutions.

• The Pure and Applied Mathematics
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• v.17 no.2
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• pp.131-136
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• 2010

Throught this paper, we will investigate some properties of left regular and strongly reduced near-rings. Mason introduced the notion of left regularity and he characterized left regular zero-symmetric unital near-rings. Also, this concept have been studied by several authors. The purpose of this paper is to find some characterizations of the strong reducibility in near-rings, and the strong regularity in near-rings which are closely related with strongly reduced near-rings.

• Bulletin of the Korean Mathematical Society
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• v.48 no.2
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• pp.387-396
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• 2011

We consider a general functional equation with time variable which arises when we investigate regularity problems of some general functional equations. As a result we prove the regularity of the initial values of the solutions. Also as an application we prove the regularity of solutions of some classical functional equations and their distributional versions.

• Journal of the Korean Mathematical Society
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• v.33 no.4
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• pp.735-745
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• 1996

This is the sequel to our paper "On projective representations of a group and its subgroups I" [4]. In Section 4[4] we proved some global properties on regularity condition. The purpose of this paper is to study local properties, that is, we shall ask how the regularity condition on subgroups is related to that on group. Throughout the paper we use the same notations as in [4].as in [4].

• Bulletin of the Korean Mathematical Society
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• v.54 no.2
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• pp.583-592
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• 2017

The paper gives the regularity of dual quaternionic functions and the dual Cauchy-Riemann system in dual quaternions. Also, the paper researches the polar representation and properties of a dual quaternionic function and their regular quaternionic functions.

• East Asian mathematical journal
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• v.30 no.5
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• pp.631-637
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• 2014

In this paper, we construct some results on the existence and regularity for solutions of neutral functional differential equations with unbounded principal operators in Hilbert spaces. In order to establish the existence and regularity for solutions of the neutral system by using fractional power of operators and the local Lipschtiz continuity of nonlinear term without using many of the strong restrictions considering in the previous literature.

• Journal of the Chungcheong Mathematical Society
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• v.22 no.3
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• pp.557-569
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• 2009

We present a new regularity criterion for suitable weak solutions of the steady-state Navier-Stokes equations near boundary in dimension five. We show that suitable weak solutions are regular up to the boundary if the scaled $L^{\frac{5}{2}}$-norm of the solution is small near the boundary. Our result is also valid in the interior.

• Journal of the Korean Mathematical Society
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• v.45 no.2
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• pp.537-558
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• 2008

Consider a weak solution u of the Navier-Stokes equations in the class $L^2((0,T);X_1(\mathbb{R}^d)^d)$. We establish a new approach to treat the regularity problem for the Navier-Stokes equation in term of the multiplier space $X_1(\mathbb{R}^d)$.

• Journal of the Korean Mathematical Society
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• v.49 no.2
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• pp.265-291
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• 2012

In this paper, we consider the regularity theory and the existence of smooth solution of a degenerate fully nonlinear equation describing the evolution of the rolling stones with nonconvex sides: $\{M(h)=h_t-F(t,z,z^{\alpha}h_{zz})\;in\;\{0<z{\leq}1\}{\times}[0,T] \\ h_t(z,t)=H(h_z(z,t),h)\;{on}\;\{z=0\}$. We establish the Schauder theory for $C^{2,{\alpha}}$-regularity of h.