• 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.

• Communications of the Korean Mathematical Society
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• v.32 no.3
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• pp.661-676
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• 2017

Let T be a bounded linear operator acting on a complex Hilbert space ${\mathfrak{H}}$. In this paper we introduce the class, denoted ${\mathcal{Q}}(A(k),m)$, of operators satisfying $T^{m{\ast}}(T^{\ast}{\mid}T{\mid}^{2k}T)^{1/(k+1)}T^m{\geq}T^{{\ast}m}{\mid}T{\mid}^2T^m$, where m is a positive integer and k is a positive real number and we prove basic structural properties of these operators. Using these results, we prove that if P is the Riesz idempotent for isolated point ${\lambda}$ of the spectrum of $T{\in}{\mathcal{Q}}(A(k),m)$, then P is self-adjoint, and we give a necessary and sufficient condition for $T{\otimes}S$ to be in ${\mathcal{Q}}(A(k),m)$ when T and S are both non-zero operators. Moreover, we characterize the quasinilpotent part $H_0(T-{\lambda})$ of class A(k) operator.

• Bulletin of the Korean Mathematical Society
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• v.40 no.4
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• pp.583-591
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• 2003

For a weighted composition operator $uC_{\varphi}$ on C(X), we determine its essential norm and the constant for its Hyers-Ulam stability, in terms of the set $\varphi(\{x\;\in\;X\;:\;$\mid$u(x)$\mid$\;\geq\;r\})$ (r > 0).

• Kyungpook Mathematical Journal
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• v.54 no.3
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• pp.365-374
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• 2014

In this paper, we introduce a new subclass of meromorphic functions defined in the punctured unit disc. We derive inclusion relationships, radius problem and some other interesting properties of this class are investigated.

• Nonlinear Functional Analysis and Applications
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• v.27 no.4
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• pp.773-784
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• 2022

The purpose of the present paper is to estimate some real parts for certain analytic functions with some applications in connection with certain integral operators and geometric properties. Also we extend some known results as special cases of main results presented here.

• Kyungpook Mathematical Journal
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• v.64 no.3
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• pp.407-416
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• 2024

The Siegel-Jacobi space is a non-symmetric homogeneous space which is very important geometrically and arithmetically. In this short paper, we propose the basic problems in the geometry of the Siegel-Jacobi space.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.628-638
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• 2017

In response to difficult employment conditions in the maritime industry and a desire to expand their career options, domestic mates are persuing DP operator training at institutions both domestically and abroad based on their shipboard experience. However, since the offshore plant service industry has not yet been established in Korea, those seeking to enter this field have difficulty acquiring qualifications and most seek work overseas for offshore shipping companies. Individuals wishing to work as DP operators are likely to face more conservative recruitment processes with overseas offshore shipping companies, focusing on career language restrictions as they will be non-native speakers relative to the foreign company, difficulty living in a multi-cultural environment, and lack of systematic information on essential job requirements. For these reasons, domestic mates have difficulty seeking jobs. Therefore, this study analyzes the capabilities and qualification required to be a DP operator to provide basic data for developing NCS standards representing a minimum level of competency. These standards can be applied by the government to develop plans for professional training for DP operators. In study, job classifications, competency standards and career development paths for DP operators have been proposed along with joint use of DP training vessels, to train specialized DP instructors. An NCS export model led by the government to activate professional training for DP operators is also presented.

• Journal of Korean Association for Spatial Structures
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• v.1 no.1 s.1
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• pp.125-134
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• 2001

The objective of this study is the development of size discrete optimum design algorithm which is based on the GAs(genetic algorithms). The algorithm can perform size discrete optimum designs of space trusses. The developed algorithm was implemented in a computer program. For the optimum design, the objective function is the weight of space trusses and the constraints are limite state design codes(1998) and displacements. The basic search method for the optimum design is the GAs. The algorithm is known to be very efficient for the discrete optimization. This study solves the problem by introducing the GAs. The GAs consists of genetic process and evolutionary process. The genetic process selects the next design points based on the survivability of the current design points. The evolutionary process evaluates the survivability of the design points selected from the genetic process. In the genetic process of the simple GAs, there are three basic operators: reproduction, cross-over, and mutation operators. The efficiency and validity of the developed discrete optimum design algorithm was verified by applying GAs to optimum design examples.

• Korean Institute of Interior Design Journal
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• v.19 no.6
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• pp.249-256
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• 2010

For guaranteeing for security of nuclear power plant, ergonomic factors have been applied to design of main control room, core area for management and control of nuclear power plant, but design elements for performance of operators have been ignored. As the behaviors of operators are important for security of nuclear power plant, space design which makes them pleasant psychologically and makes them maintain attention on security equipments ceaselessly is required. Therefore, the purpose of this study is to analyze space characteristics of main control rooms according to regulations of nuclear power plant and general guidelines of space design, and to offer basic data for designing of main control room which makes operators pleasant psychologically and physically. At first, theoretical issues related with design of main control room are reviewed and several premises of space are developed by abstracting design elements from common space and regulations of nuclear power plant and, then integrating each design elements interactively. In short, the improvement of system environment based on human-machine interface space has brought about perceptual, cognitive, and spatial changes and has realized next generation of main control rooms. And, differences and similarities between ordinary space and main control room, which ergonomic sizes and regulations are applied and is VDT environment based on LDP, are discussed in relation to 13 design elements and 17 space premise.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.382-387
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• 2004

As the increasing needs in the industrial filed, many studies for the 3D CAD system are carried out. There are two types of 3D CAD system. One is manifold modeler, the other is non-manifold modeler. In the manifold modeler only 3D objects can be modeled. In the non-manifold modeler 3D, 2D, 1D, and 0D objects can be modeled in a unified data structure. Recently there are many studies on the non-manifold modeler. Most of them are focused on finding unknown topological entities and representing all kinds of topological entities found. In this paper, efficient data structure is selected. The boundary information on a face and an edge is included in this data structure. The boundary information on a vertex is excluded considering the frequency of usage. Because the disk cycle information is not required in most case of modeling. It is compact. It stores essential non-manifold information such as loop cycle and radial cycle. A suitable Euler-Poincare equation is studied and selected. Using the efficient data structure and the selected Euler-Poincare equation, 18 basic Euler operators are implemented. Several 3D models are created using the implemented modeler. A non-manifold modeling can be carried out using the implemented 3D CAD system. The results of this paper could be used in the further studies such as an implementation of Boolean operators, and a translation of 2D CAD drawings to 3D models.