• East Asian mathematical journal
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• v.32 no.5
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• pp.641-649
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• 2016

In this paper, using three types of conjugations in a bicomplex number filed $\mathcal{T}$, we provide some basic definitions of bicomplex number and definitions of regular functions for each differential operators. And we investigate the corresponding Cauchy-Riemann systems and the corresponding Cauchy theorems in $\mathcal{T}$ in Clifford analysis.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.336-339
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• 2008

Convergence services are very important to mobile operators in next generation mobile networks. However, mobile operators cannot deal with all convergence services because there are numerous convergence services. Thus, they should select and develop main technologies to provide convergence services which are areas to grow our business. In this paper, we introduce basic technologies to provide convergence services and then present some evaluation models to select an important area and technology.

• Nonlinear Functional Analysis and Applications
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• v.26 no.3
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• pp.531-551
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• 2021

In this paper, we consider a mixed boundary value problem to a class of nonlinear operators containing p(x)-Laplacian. More precisely, we consider the problem with the Dirichlet condition on a part of the boundary and the Steklov boundary condition on an another part of the boundary. We show the existence of at least three weak solutions under some hypotheses on given functions and the values of parameters.

• Nonlinear Functional Analysis and Applications
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• v.27 no.1
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• pp.111-119
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• 2022

In this article, we prove that diskcyclic C₀-semigroups exist on any infinite-dimensional Banach space. We show that a C₀-semigroup (T_t)_t≥0 satisfies the diskcyclicity criterion if and only if any of T_t's satisfies the diskcyclicity criterion for operators. Moreover, we show that there are diskcyclic C₀-semigroups that do not satisfy the diskcyclicity criterion. Also, we state various criteria for diskcyclicity of C₀-semigroups based on dense sets and d-dense orbits.

• Nonlinear Functional Analysis and Applications
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• v.28 no.1
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• pp.81-93
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• 2023

By utilizing a certain Libera integral operator considered on analytic multivalent functions in the unit disk U. Using the hypergeometric function and the Libera integral operator, we included a new convolution operator that expands on some previously specified operators in U, which broadens the scope of certain previously specified operators. We introduced and investigated the properties of new subclasses of functions f (z) ∈ A_p using this operator.

• Nonlinear Functional Analysis and Applications
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• v.27 no.4
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• pp.813-837
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• 2022

In this paper we consider inverse problem for a general class of nonlinear stochastic differential equations on Hilbert spaces whose generating operators (drift, diffusion and jump kernels) are unknown. We introduce a class of function spaces and put a suitable topology on such spaces and prove existence of optimal generating operators from these spaces. We present also necessary conditions of optimality including an algorithm and its convergence whereby one can construct the optimal generators (drift, diffusion and jump kernel).

• Nonlinear Functional Analysis and Applications
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• v.27 no.4
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• pp.895-902
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• 2022

The aim of this paper is to construct a new method for finding the zeros of the sum of two maximally monotone mappings in Hilbert spaces. We will define a simple function such that its set of zeros coincide with that of the sum of two maximal monotone operators. Moreover, we will use the Newton-Raphson algorithm to get an approximate zero. In addition, some illustrative examples are given at the end of this paper.

• Journal of applied mathematics & informatics
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• v.29 no.1_2
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• pp.459-468
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• 2011

Let T ${\in}$ L(X), S ${\in}$ L(Y), A ${\in}$ L(X, Y) and B ${\in}$ L(Y, X) such that SA = AT, TB = BS, AB = S and BA = T. Then S and T shares the same local spectral properties SVEP, Bishop's property (${\beta}$), property $({\beta})_{\epsilon}$, property (${\delta}$) and and subscalarity. Moreover, the operators ${\lambda}I$ - T and ${\lambda}I$ - S have many basic operator properties in common.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1996.09a
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• pp.59-80
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• 1996

This stud was projected to develop the training course for VTS operators in Korea. The studying method was literature survey and questionnaire. It was properly used and analyzed that such as the concerned literature international symposium results and letters from Canada USA Japan and other countries in order to compare their contents This study proposed the basic training course for VTS operators in Korea on the basis of these data. and also concluded as followings. First the number and level of Korea VTS should be decided. Second the training organization and staff should be build and pointed. Third the VTS trainee should selected and the training level & period should be eatablished, Fourth The training should be the VTS training curriculum. Fifth The VTS operator certificate should be issued by proper test. But this need further study through the analysis for the questionnaire regarding to Korea VTS Training Program.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.8 no.1
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• pp.38-43
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• 1997

Backgroud : Now a days, most studies for professional voice user have been performed after artificial voice abuse without consideration of environmental and personal factors, and occupational specificity, therefore those studies have some problems. Objectives : To make a basic guideline for the management of untrained professional voice user, practically we ananalyzed the voice of experimental group. Materials and methods : Just after working, the sustained vowel sounds of the 15 female telephone operators (subjective group) and the 20 normal female persons (control group) were analysed, using a history paper, acoustic analyzer and videostroboscopy. Results : The most common symptom in subjective group was dysphonia. Stroboscopic findings in subjective group were as following ; posterior chink 11 cases (73%), incomplete closure 2 cases (13%), anterior chink 1 case (7%). The mean maximal phonation time in telephone operators was 12.8 seconds and in control group was 16.8 seconds. Jitter, pitch pertubation quotient (PPQ), shimmer and amplitude pertubation quotient (ASQ) were significantly increased in subjective group than control group, but there is no difference between two group in fundamental frequency and noise to harmonic ratio. Conclusion : Untrained professional voice user needs professional career guidance and counseling. And when we manage the untrained professional voice user, we should consider specific occupational, personal and environmental factors as well as laryngeal factors.