• International journal of advanced smart convergence
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• v.12 no.4
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• pp.20-25
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• 2023

Increasing demand for increasing higher data rate in order to solve computationally tasks timely and connecting many user equipment simultaneously have requested researchers to develop novel technology in the area of mobile communications. Intelligent reflecting surface (IRS) have been enabling technologies for commercialization of the fifth generation (5G) networks and the sixth generation (6G) systems. In this paper, we investigate a bit-error rate (BER) analysis on IRS technologies for non-orthogonal multiple access (NOMA) systems. First, we derive a BER expression for IRS-NOMA systems with Rician fading channels. Then, we validate the BER expression by Monte Carlo simulations, and show numerically that BER expressions are in good agreement with simulations. Moreover, we investigate the BER of IRS-NOMA systems with Rician fading channels for various numbers of IRS elements, and show that the BERs improve as the number of IRS elements increases.

• Korean Journal of Childcare and Education
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• v.16 no.2
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• pp.67-87
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• 2020

Objective: In order to provide basic data that can strengthen the recognition of continuity of early childhood and primary education, early childhood education and early childhood special education teachers at inclusive child care and education settings participated in this study. Methods: The researchers conducted a survey on 192 early childhood teachers and 167 early childhood special education teachers in Seoul and Gyeonggi-do province. The collected data were analyzed statistically. Results: First, early childhood special education teachers were higher than early childhood teachers statistically on the prerequisite elements of continuity. Second, early childhood education teachers were higher than early childhood special education teachers statistically regarding the prerequisite educational techniques required for continuity of early childhood and primary education. In particular, early childhood teachers put more of an emphasis on learning and sociality-communication than early childhood special education teachers did. Conclusion/Implications: It is necessary that in-service education on prerequisite elements be stressed, and there be more detailed activities and education about programming and its utilization for early childhood special education teachers.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.5-8
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• 2001

A three node flat triangular element incorporating Layerwise Zig-Zag Theory(HZZT) is developed suitable for analyzing damped laminated composite structures. Using an interdependent kinematic relation, the higher order shear rotations are replaced by in-plane displacements, a transverse displacement and section rotations, which result in three translations and two rotations. Natural frequencies and modal loss factors of cantilevered laminated plates with embedded damping layers are calculated with the zig-zag triangular element and compared to the experimental results and MSC/NASTRAN results using a layered combination of plate and solid elements.

• Science of Emotion and Sensibility
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• v.16 no.4
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• pp.545-556
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• 2013

This study has established the GUI design elements of mobile phones as color, text, layout, graphic icon, and video, under the purpose of exploring the relevance between such elements and brand preference among senior citizens. To accomplish the objective, a model and hypotheses were established, which were tested through a multiple regression analysis. The findings are as follows. First, when the statistical significance was examined by GUI design element of mobile phones, the following results were obtained: Color, text, layout, graphic icon, and video were statistically significant at the significance level given, indicating that such elements all affect brand preference. Second, the relative influence of GUI design elements of mobile phones on brand preference was revealed in the following order: text, color, video, graphic icon, layout. It indicates that boosting the brand preference of senior citizens for mobile phones requires considering 'text' and 'color' first before any other element. In addition, as the influence of 'text' and 'color' becomes greater, the brand preference also becomes higher.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.139-142
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• 2003

Traditionally, the thickness of fire protection materials of structural elements such as beam and column have been decided by fire test using the predominant steel section of $H-300{\times}300{\times}10{\times}15$ for column and $H-400{\times}200{\times}8{\times}13$ for beam in Korea. But this way of determination of fire protection thickness yields very unduly results. Because the temperature-increment rate of structural steel elements depends mainly on magnitude of their cross-areas. In general, the thicker size of cross-areas for structural elements, the lower temperature shows up. It had already proved that the fire protection thickness only depends on the size of cross-areas and the fire protection method for three-fide or four-side exposed conditions in European countries, the United State of America and so on. To demonstrate there would be differences among various cross-areas for structural elements, we conducted several fire tests with full-scale specimens of beams and columns. For the determination of critical temperature for steel section when the fire resistant performance is needed to be decided, we conducted with a loaded fire test for beam and column, respectively. The small column in 1.0 meter length and beam in 1.5 meter length were used in order to deprive the rational fire protection thickness of structural elements such as beam and column, respectively. After test, we could obtain there were significant temperature lass between higher cross-areas and lower cross-areas. The critical temperature of steel as a criterion is used 538$^{\circ}C$ for column and 593$^{\circ}C$ for beam which is from ASTM E 119 because we don't make provisions as critical temperature by elements. We could consider that the best way of determination of fire protection thickness is using the following multi-regression equation which was deprived from several fire tests using the concept of section factor, FR(column) = 0.17 +5191.49t A/Hp + 40.77t, FR(beam) = 0.25 +6899.31t A/Hp + 32.60t(where, FR means fire resistant time, t means thickness, A means cross-area and Hp means heated parameter).

• Journal of the Korean Institute of Landscape Architecture
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• v.29 no.4
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• pp.24-33
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• 2001

The purpose of this paper is to examine the differences of user´s satisfaction of development elements of natural recreation forest(NFR) developed by public and private bodies in order to answer the research question: What is the differences of user´s satisfaction of development elements of NFR\ulcorner After reviewing the literature, mechanism of outdoor recreation, and development elements in NRF, we constructed the conceptual framework and have formulated the hypothesis of this research. We had obtained data through a questionnaire, which surveyed 584 visitors at 10 of the 72 natural recreation forests in Korea in 1999. We have analyzed the data using he descriptive statistical method, the mean difference test, and logistic regression method. We have found that 1) all the development elements have turned out to be significantly different from the mean difference test, 2) the two elements of atmosphere and activity have turned out to be statistically significant in determining the difference of NFR developed by public and private body in logistic regression analysis while user´s satisfaction in recreational resources, facilities and service make no differences between public and private NRF, 3) the higher the degree of user´s satisfaction in atmosphere and activity at NFR, the more the NFR developed by private body, and 4) their relative contribution of atmosphere and activities on whether the NFR is developed by public or private body have been turned out to have 0.258 and 0.242 respectively, which have a similar importance. The research results suggest that a guideline for the creation of marketable NFR by public and private developer, and development of use-programs and recreational atmosphere be recommended in the planning and development process of NRF. The approach and anlaysis method adopted by this research is highly useful for an evaluation of NRF developed by the tow bodies and development of devices for increasing user´s satisfaction and marketing positioning of NRF by the tow developers. It is recommended that more empirical study on individual development elements affecting user´s satisfaction be performed in the future.

• The Korean Journal of Mycology
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• v.13 no.1
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• pp.53-55
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• 1985

To determine contents of inorganic elements of Ganoderma lucidum (Fr.) Karsten, the horn-shaped carpophores and the pileus of Ganoderma lucidum were incinerated and analyzed by inductively coupled plasma atomic emission spectrophotometry. The ash contents of the pileus and the horn-shaped carpophore were 1.48 and 1.40 % respectively. The pileus contained calcium, magnesium, sodium, manganese, iron, zinc and germanium in that order. The horn-shaped carpophore contained magnesium, calcium, zinc, manganese, iron, copper and germanium in that order.

• Structural Engineering and Mechanics
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• v.85 no.2
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• pp.147-161
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• 2023

Based on the ideas of variational differential quadrature (VDQ) and finite element method (FEM), a numerical approach named as VDQFEM is applied herein to study the large deformations of plate-type structures under static loading with arbitrary shape hole made of functionally graded graphene platelet-reinforced composite (FG-GPLRC) in the context of higher-order shear deformation theory (HSDT). The material properties of composite are approximated based upon the modified Halpin-Tsai model and rule of mixture. Furthermore, various FG distribution patterns are considered along the thickness direction of plate for GPLs. Using novel vector/matrix relations, the governing equations are derived through a variational approach. The matricized formulation can be efficiently employed in the coding process of numerical methods. In VDQFEM, the space domain of structure is first transformed into a number of finite elements. Then, the VDQ discretization technique is implemented within each element. As the last step, the assemblage procedure is performed to derive the set of governing equations which is solved via the pseudo arc-length continuation algorithm. Also, since HSDT is used herein, the mixed formulation approach is proposed to accommodate the continuity of first-order derivatives on the common boundaries of elements. Rectangular and circular plates under various boundary conditions with circular/rectangular/elliptical cutout are selected to generate the numerical results. In the numerical examples, the effects of geometrical properties and reinforcement with GPL on the nonlinear maximum deflection-transverse load amplitude curve are studied.

• Journal of Powder Materials
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• v.11 no.4
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• pp.314-321
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• 2004

The elastic moduli of simulated dry process fuels with varying composition and density were measured in order to analyze the mechanical properties of a dry process fuel pellet. Resonant ultrasound spectroscopy(RUS) which can determine all elastic moduli with one set of measurements for a rectangular parallelepiped sample was used to measure the elastic moduli of UO$_{2}$ and simulated dry process fuel. The simulated dry process fuel showed a higher value of Young's modulus than UO$_2$ due to the presence of metallic precipitates and solid solution elements in the UO$_{2}$ matrix. The correlation between Young's modulus and porosity(P) of simulated dry process fuel was found to be 231.4-651.8 P (GPa) at room temperature. Dry process fuel with a higher burnup showed higher Young's modulus because total content of fission product element was increased.

• Structural Engineering and Mechanics
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• v.50 no.2
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• pp.181-199
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• 2014

Locking phenomenon is a mesh problem and can be staved off with mesh refinement. If the studier is not preferred going to the solution with increasing mesh size or the computer memory can stack over flow than using higher order plate finite element or using integration techniques is a solution for this problem. The purpose of this paper is to show the shear locking phenomenon can be avoided by increase low order finite element mesh size of the plates and to study shear locking-free analysis of thick plates using Mindlin's theory by using higher order displacement shape function and to determine the effects of various parameters such as the thickness/span ratio, mesh size on the linear responses of thick plates subjected to uniformly distributed loads. A computer program using finite element method is coded in C++ to analyze the plates clamped or simply supported along all four edges. In the analysis, 4-, 8- and 17-noded quadrilateral finite elements are used. It is concluded that 17-noded finite element converges to exact results much faster than 8-noded finite element, and that it is better to use 17-noded finite element for shear-locking free analysis of plates.