• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.5
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• pp.487-499
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• 2009

The postprocessing technology has been advanced diversely to accommodate the tendency of increasingly refined and complicated practices of finite element modeling in pace with enhanced capabilities of computers and improved algorithm of equation solvers. As a result of such progresses in both hardware and software, it became practically meaningful to inspect and analyze the elasto-plastic behavior using the intermediate results from the increasing number of incremental and iterative processes. This paper is concerned about the new methods of postprocessing with computer graphic visualization of elasto-plastic behavior on the basis of the theoretically reorganized analysis results. This paper proposes a new method of rendering the plastic zone, and new approaches of analyzing and interpreting the elasto-plastic behavior using the graphical information visualized in the form of the yield surface and the stress path, or in the form of the Mohr circles and the failure envelope.

• Progress in Medical Physics
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• v.10 no.3
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• pp.141-149
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• 1999

This research analyzed the HRV signals by using wavelet transform to observe the activities of autonomous nervous system in a sleep state. This research also restructured the HRV signals from electrocardiogram and by using coefficient which was obtained through wavelet transform, analyzed the signals by frequency bandwidth. Then compared the analyzed results with existing frequency analyzing method using AR model techniques. The suggested wavelet coefficient from power spectrum component in the study shows a similar tendency with the results from FFT or AR model technique. Therefore, it can be found that power spectrum analyzing method by wavelet coefficient is a useful as a tool for analyzing autonomous nervous system activities using HRV signals. Since the suggested method able to clearly depict the progression of change in time zone, which was once impossible with the existing methods, it is presumed that it will be useful in other physiological signals.

• Journal of Korea Water Resources Association
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• v.40 no.4
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• pp.287-297
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• 2007

The procedures for identifying channel network are suggested by exploring the scaling property between the local slope and the contributing area, given that the area threshold criterion is an indispensable complement to the slope-area threshold criterion. Through the use of the above procedures and the field data, the basin slopes illustrate the trends of large scatters in space for the geomorphologic/topographic factors. According to the scaling regimes of them both the forms of landscape can be classified as topographic divergence and convergence. The presentation of the procedures proposed in this study is implemented in the case study on Seolma experimental catchment in Korea. As a result the dynamic behaviors of basin are confirmed, and thus the dynamics of channel head advance and channel network are shown to represent better than the method using the topographic chart manually.

• Spatial Information Research
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• v.14 no.4 s.39
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• pp.391-401
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• 2006

We propose a method for geographically enhanced representation of social networks and implement a Web-based 3D visualization of geographical contexts in social networks. A renovated social network graph is illustrated by using two key components: (i) GWCMs (geographically weighted centrality measures) that reflect the differences in interaction intensity and spatial proximity among nodes and (ii) MSNG (map-integrated social network graph) that incorporates the GWCMs and the geographically referenced arrangement of nodes on a choroplethic map. For the integrated 3D visualization of the renovated social network graph, we employ X3D (Extensible 3D), a standard 3D authoring tool for the Web. An experimental case study of regional R&D collaboration provides a visual clue to geographical contexts in social networks including how the social centralization relates to spatial centralization.

• Journal of Wetlands Research
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• v.19 no.1
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• pp.122-131
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• 2017

Remotely sensed satellite data is easier to collect and better to represent local phenomenon than a site data. So they can contribute to the activation and development of many research. However, it is necessary to improve spatial resolution suitable for application in the area of complex topography such as the Korean Peninsula. In this study, finer resolution Land Surface Temperature (LST) was downscaled from 4 km to 500 m by combining GOCI with MI data of Communication, Ocean and Meteorological Satellite (COMS). It was then statistically analyzed with LST data observed from the ASOS sites to validate its applicability. As a result, it was found that the errors decreased and correlation increased at the most validation sites, also the spatial distribution analysis showed a similar tendency but it expressed the complicated terrain better. This study suggests possibility of expanding the application range of COMS by producing finer resolution data available in various studies.

• The Journal of the Korea Contents Association
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• v.22 no.4
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• pp.458-467
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• 2022

The objective of this study is to investigate the meaning of children perceived by pre-service childcare teachers through metaphor analysis. To this end, data were collected from a group of 288 pre-service childcare teachers majoring in childcare at a university in Gyeonggi-do from the 4th week of May until the 2nd week of June 2021. As a result of the study, the meaning of children was categorized into 'being in need of care,' 'being affected by the environment,' 'being with personality,' 'precious and invaluable being,' 'being giving joy,' 'being who will lead the future,' 'pure and innocent being,' and 'being who develops teachers and parents.' Pre-service teachers showed the highest tendency to perceive children as 'beings in need of care' among the eight categories. The metaphorical expressions, 'sprout,' 'seed,' 'flower,' 'canvas,' 'sponge,' and 'mirror,' in descending order of frequency, were most commonly used among 138 metaphorical expressions. The findings of this study are expected to broaden the understanding of the pre-service teachers' perception of children and provide preliminary data for qualitative support and improvement plans for training pre-service childcare teachers in the future.

• Journal of The Korean Association For Science Education
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• v.22 no.3
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• pp.466-477
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• 2002

It was proposed that proper problem solving practice should improve students' questioning in physics. In the previous researches, improvement in students' questioning was observed after practice of making questions given the examples of desirable questions. In this study, the problem solving strategies used by experts were introduced to students in the form of step-by-step guide to follow in problem solving practice. The directions in the guide were concrete and operational for students to understand the expected behaviors explicitly. It was assumed that students could pinpoint the difficulty specifically through this guide, which would result in positive effects on students' recognition and expression of their own questions. The subjects in this study were college freshmen enrolled in the introductory physics for science or engineering major. The physics problems from the textbook were solved and practiced in the traditional way for controlled group. Worksheets designed to follow experts' problem solving strategies were used for the experimental group. Two groups were taught in the same way during lecture part of the class. Students were asked to describe the difficulties they had during homeworks or tests. Questions in this study means these descriptions written by students although they were not necessarily in the form of interrogative sentences. The questions were analyzed both in quantity and quality. Quantitatively, more students spontaneously turned in their questions in the experimental group than in the controlled group. Regarding the quality, there were more students in the experimental group than in the controlled group who described their difficulties in detail or recognized the need for the procedural knowledge.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.109-122
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• 2003

In order to release the pressure fluctuations and micro-pressure wave induced by the entering of train into the small cross sectional tunnel, it has been reported that the construction of air shaft has more advantages with respect to economy and constructability than the enlargement of cross section of existing tunnel. The field monitorings and analytical studies were conducted simultaneously in this study to analyze the mechanical behavior of existing railway tunnel, new cross tunnel and new shaft by the construction of new shaft nearby. The results showed that the minimum distance from existing tunnel to new shaft which secures the stability of existing tunnel was found to be half diameter of existing tunnel. On the three dimensional mechanical behavior of existing tunnel by the construction of new shaft, the results from the analytical study and field monitoring had a similar trend. The analytical study and field monitoring results, however, produced somewhat different results on the mechanical behavior of new shaft itself. These conclusions induce that the analytical method which has been applied on the analyses of horizontal tunnel could not be applied in the same way on the analysis of vertical shaft.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.4
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• pp.185-191
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• 2004

A mooring system can be applied to keep the position of a floating structures. In this study, the structural analysis is carried out to analyze the dynamic characteristics of a mooring line for a floating breakwater. A three-dimensional equations of motion for a submerged chain are derived. Bending stiffness is considered for the necessary restoring force in the regions of zero tension. A fortran program is to be developed by employing finite difference method. In the algorithm, an implicit time integration and Newton-Raphson iteration are adopted. The results of simulation show good agreement in tension response pattern with the experimental results of a reference. The results of this study can contribute for the design of mooring system for a floating breakwater.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1C
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• pp.7-16
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• 2012

In this paper, using the principle of Static Measurement Methods suggested by Huang (1998), a new experimental device has been made and used in order to calculate the unsaturated permeability of Nak-dong river sand with silt which is an important basic property in the unsaturated soil. This device was designed to measure changes of the unsaturated permeability according to the increase of matric suction. The value of the unsaturated permeability obtained in testing and that obtained using the empirical permeability functional formula were compared and analyzed. As a result, the value of the unsaturated permeability tends to be decreased according to the increase of relative density, silt content and matric suction. This tendency shows it is very closely related to the change of moisture content and void ratio. The empirical permeability functional formula presented by Frelund & Xing (1995) was regarded as the most appropriate model to represent the unsaturated permeability of Nak-dong River silty sand.