• Journal of the Korean Geotechnical Society
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• v.37 no.10
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• pp.65-76
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• 2021

There is a possibility of cavities occurring inside and behind the lining of an aged tunnel structure. In most cases, it is not easy to check the cavity because it exists in a place where visual inspection is impossible. Recently, attempts have been made to evaluate the condition of the tunnel lining and the backfill materials using non-destructive tests such as Ground Penetrating Radar, and various related model tests and numerical analysis studies have been conducted. In this study, the GPR signal characteristics for tunnel lining model testing were analyzed using gprMax software, which was compared with model test results. The numerical model applied to the model test reasonably simulated the electromagnetic wave signal according to the change of the material such as tunnel lining and internal cavity. Using the verified GPR model, B-scan data for the development of the GPR signal analysis technique were obtained, which can evaluate the thickness of the tunnel lining, the presence of the cavity, the effect of the waterproof membrane, and the frequency band.

• Journal for History of Mathematics
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• v.35 no.1
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• pp.19-39
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• 2022

This paper aims to examine how the public perception of mathematics changed in England in the 19th century. As rapid industrial and social developments took place in the 19th century, the educational environment underwent great changes, and the value and public perception of mathematics also changed. Mathematics took a new position in the terrain of educational reform in the late 19th century. In this study, I analyzed the actual condition of mathematics education in elementary and secondary schools, popular educational institutions, and universities in England in the first half, middle, and second half of the 19th century, and compared what values and usefulness of mathematics education were justified in each institution. I also examined how satirical magazine Punch satirized the public understanding or view on mathematics at each period. It is to be hoped that this study will have significant implications for raising the public's positive perception of mathematics in modern society.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.05a
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• pp.270-273
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• 2002

The purpose of our study is to clarify about the influence that the visual information gives to the brain activities when pressure exerted the abdomen by waist belts. The visual information means that the some different visual information is inputted it, and the brain activity is evaluated by Electroencephalogram(EEG) measurements. At the same time, we carried out the sensory tests and verified about the relations between the psychological stress and the brain activities. There was a difference in change in the power of the $alpha$ wave with the eyes opened between man and woman. from the result of the sensory test, in the case of under the condition in the darkness with the eyes opened, there was no change in the a wave with before the pressure and after the pressure. In the other cases, $alpha$ wave changed in the same way with before the pressure and after the pressure. In the case of the visible and the invisible in pressure place, $alpha$ wave changed in the same way with before the pressure and after the pressure, but there was a difference in value. From the above, it isn't recognized that the visual information is influencing a pressure sense but some influences are given to it to the brain activities.

• The Journal of Economics, Marketing and Management
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• v.4 no.4
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• pp.25-28
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• 2016

In this paper we expand on the notion of "integration" in terms of the variety of ways in which it would manifest itself in business education. Our main argument is that "integration" is multidimensional and has been manifest in pedagogy, research and service dimensions of university programs for a long time. However, assessments of "integration" efforts have been spotty thus far and only recently are being formalized. We present several examples in business curriculum and with increased focus on formal assessments of "integration" efforts, business education will become more pragmatic. The goal of this paper is to unpack the broad construct of "integration," and discuss its historical and current manifestations in business education. Ultimately, we conclude that while the process of integrative thinking is well underway for a long time in business education, the assessment of outcomes of integrative thinking is just taking root through formal ETS tests. We believe that integrative thinking in business education is an ultimate indicator of the effectiveness of the business curriculum, as students skilled in this area will be best prepared for the real-life jobs in the market place.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.1
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• pp.23-28
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• 2022

The eLoran system is a high-power terrestrial navigation system that is recognized as the most appropriate alternative to complement the GNSS's vulnerability to radio frequency interference. Accordingly, Korea has conducted eLoran technology development projects since 2016. The eLoran system developed in Korea provides 20 m positioning accuracy to maritime user in Incheon and Pyeongtaek harbor. To accurately calculate the position with the eLoran signal, it is necessary to apply a compensation method that mitigates the propagation delay. In this paper, we develop the compensation method to mitigate the eLoran signal propagation delay and evaluate the positioning performance in Incheon harbor. The propagation delay due to the terrain characteristics is pre-surveyed and stored in the user receiver. Real-time fluctuations in propagation delay compared to the pre-stored data are mitigated by the temporal correction generated at a nearby differential Loran station. Finally, two performance evaluation tests were performed to verify the positioning accuracy of the Korean eLoran system. The first test took place in December 2020 and the second in April 2021. As a result, the Korean eLoran service has been confirmed to provide 20 m location accuracy without GPS.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.3
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• pp.133-140
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• 2008

This paper proposes an effective k-D tree traversal algorithm for ray tracing on a GPU. The previous k-D tree traverse algorithm based on GPU uses bottom-up searching from a leaf to the root after failing to find the ray intersected primitive in the leaf node. During the bottom-up search the algorithm decides the current node is visited or not from the parent node. In such a way, we need to visit the parent node which was already visited and the duplicated bounding box intersection tests. The new k-D tree traverse algorithm reduces the brother and parent duplicated visit by using an efficient method which decides whether the brother node is already visited or not during the bottom-up search. Also the algorithm take place bounding box intersection tests only for the nodes which is not yet done. As a result our experiment shows the new algorithm is about 30% faster than the previous.

• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.127-135
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• 2005

In order to analyze effects of strain rate on consolidation characteristics of Busan clay, a series of constant rate of strain (CRS) consolidation tests with different strain rate and incremental loading tests (ILT) were performed. From experimental test results on Busan clay, it was found that the preconsolidation pressure was dependent on the corresponding strain rate occurring during consolidation process. Also, consolidation curves normalized with respect to preconsolidation pressure gave a unique stress-strain curve. Coefficient of consolidation and permeability estimated from CRS test had a tendency to converge to a certain value at normally consolidated range regardless of strain rate. An increase in excess pore pressure was observed after the end of loading without change of total stress on the incremental loading test, which phenomenon is called Mandel-Cryer effect. It was also found that rapid generation of excess pore pressure took place due to collapse of soil structure as effective stress approached to preconsolidation pressure.

• Journal of the Korean Geotechnical Society
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• v.38 no.9
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• pp.53-67
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• 2022

Micropiles are cast-in-place-type piles with small diameters. They are widely used for the foundation reinforcement of existing buildings and structures because this technique is easy to construct and economic. A base expansion structure is developed following the mechanism of radial expansion at the pile tip under compression. Numerical analysis, durability tests, and centrifuge tests have been conducted using the base expansion structure. In this study, three-dimensional numerical modeling was performed to describe the behavioral mechanism of the base expansion structure using steel bar penetration under compressive loading, and numerical analyses using centrifuge test conditions were performed for the comparative studies. Additionally, the base structure was modified based on the results of lab-scale analyses, and the bearing capacities of micropiles were compared using field-scale numerical analyses under various ground conditions.

• International journal of advanced smart convergence
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• v.2 no.2
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• pp.1-6
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• 2013

Convergence in technology and media makes it possible to augment nurturing by making blended infrastructures with new digital resources available in learning environments at schools. A game-based provision of educationally-valuable content within a collective, virtual environment combined with an analysis of events in the game after it has been played (blended nurture environment) may help to better communicate human values especially where old-fashioned discussion methods fail or do not fulfill the promise of effective, educational institution-based methods of bringing up. In this paper we discuss the use of behavioural metaphors in game-based blended-nurture scenarios for computer games and pedagogical-psychological tests. Upbringing demands an active intervention in the process of children growing up and the courage to place higher expectations on ourselves and our own lifestyles. Decisions and the behaviour of the younger generation are often irrational and the resulting effects can have destructive consequences. Nowadays, games take on the role of modern storytellers. With the help of complex analogies in games, a variety of situations can be depicted in an eye-catching way and later discussed.

• Korean Journal of Human Ecology
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• v.17 no.3
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• pp.389-397
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• 2008

This study is investigating the perceptions of early childhood teachers on early childhood music activity. The subjects are early childhood teachers(N=217) working at kindergartens and day care centers in Jeonbuk Province. The data were collected from a questionnaire and analyzed with the tests of frequency, Cronbach's $\alpha$, t-test, ANOVA and Duncan. The results are as follow: first, the early childhood teachers are being aware of importance of infant music activity in the order of "aesthetic exploration", "artistic expression", and "art appreciation". Second, according to teachers' working place, the teachers have no differences of perception in early childhood music activities, while, according to children's age in the class which the teachers are taking charge of, they show differences of perception in the activities of "exploring movements " and "respect for artistic expression". Third, according to the early childhood teacher's career, they have difference of perception in "singing" activity only, while according to their education level, they have no differences of perception in all music activities. According to teachers' age, they have differences of perception in the activities of "aesthetic exploration", "exploring sound", and "singing".