• Journal of Creative Information Culture
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• v.7 no.4
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• pp.265-277
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• 2021

Data is the core of AI technology. With the development of technology, AI technology is also accelerating as the amount of data increases explosively than before. However, compared to the interest in AI education, research on data education with AI is still insufficient. According to the case analysis of exsisting AI data education, there were cases of educating the process and part of data science, but it was hard to find studies related to data collection. Cause physical computing tools have a positive effect on AI education for elementary school students, data collection cases using tools were studied, but researches related to data collection were rare. Therefore, in this study, an efficient data collection method using physical tools was designed. A structural diagram of a data collection program was created using COBL S, a modular physical computing teaching tool, and examples of program screens from the service side and the user side were configured. This study has limitations in that the establishment of an AI education platform that can be used in conjunction with future program production and programs should be prioritized as a proposal in terms of design.

• Structural Engineering and Mechanics
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• v.85 no.5
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• pp.679-691
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• 2023

Many codes allow designers to use the bending moment diagram computed by elastic analysis and modify it by a certain amount of moment redistribution (MR) to account for plastic behaviour of continuous beams. However, several researchers indicated that the MR at the ultimate limit state (𝛽_u) for some beams deviate significantly from the specified values of various codes. This paper examines the applicability of the provisions on 𝛽_u in ACI 318-19 and Eurocode 2 through numerical investigations and comprehensively explores the influencing factors. The results show that some parameters not considered in those codes influence 𝛽_u to a certain extent, where the ratio of tensile reinforcement ratio at intermediate support to tensile reinforcement ratio at midspan (𝜌_s1/𝜌_s2) and load type are crucial parameters to consider. The specific combination of these two parameters may make the codes overestimate or significantly underestimate the 𝛽_u. On the other hand, the yield state of both critical sections is found to have an important influence on the influence degree of each parameter on 𝛽_u. The yield conditions are investigated, and an empirical judgment equation is proposed. In addition, the influence laws of the critical parameters on 𝛽_u have been further proved by theoretical derivation. Finally, due to 𝜀_t is found to have a better linear correlation with 𝛽_u than x_u/d, equations as a function of 𝜀_t for predicting the 𝛽_u of continuous beams under the two loads are proposed, respectively.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.126-132
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• 2023

Recently, the consideration of eco-friendly technology to reduce greenhouse gas is being emphasized in the aviation field. Various studies for applying electro-mechanical actuators that control mechanical linear and rotational movements using electricity as the primary power source are in progress. In this study, the fatigue analysis of the electro-mechanical actuator for the front wheel steering of a single aisle aircraft was carried out. A unit load stress table was constructed for the vulnerable part selected through structural analysis, and the representative stress for each load profile was calculated using the unit load stress table constructed for the vulnerable part. Then, individual profiles of representative stress group were extracted from continuous load profiles by applying the rainflow counting method. The damage of each profile was calculated by applying the S-N diagram. Finally, the total damage in the vulnerable parts was calculated by the linear cumulative damage law, and the fatigue life of the electro-mechanical actuator for the front wheel steering of a single aisle aircraft was evaluated.

• Composites Research
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• v.36 no.4
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• pp.259-263
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• 2023

This study investigated the open hole tensile (OHT) properties of carbon fiber/epoxy composites and compared them to bolt joint tensile (BJT) properties. The net nominal modulus and strength (1376 MPa) were found to be higher than the gross nominal strength (1041 MPa), likely due to increasing hole size. The OHT and BJT specimens exhibited similar stiffness, as expected without bolt rotation causing secondary bending. OHT specimens experienced a sharp drop in stress indicating unstable crack propagation, delamination, and catastrophic failure. BJT specimens failed through shear out on the bolt side and bearing failure on the nut side, involving fiber kinking, matrix splitting, and delamination, resulting in lower strength compared to OHT specimens. The strength retention of carbon fiber/epoxy composites with open holes was 66%. Delamination initiation at the hole's edge caused a reduction in the stress concentration factor. Filling the hole with a bolt suppressed this relieving mechanism, leading to lower strength in BJT specimens compared to OHT specimens. Bolt joint efficiency was calculated as 15%. The reduction in strength in bolted joints was attributed to fiber-matrix splitting and delamination, aligning with Hart Smith's bolted joint efficiency diagram. These findings contribute to materials selection and structural reliability estimation for carbon fiber/epoxy composites. They highlight the behavior of open hole and bolt joint configurations under tensile loading, providing valuable insights for engineering applications.

• Journal of the Korean Geotechnical Society
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• v.24 no.4
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• pp.23-36
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• 2008

This study describes model tests on instrumented rectangular-shaped passive row piles embedded in horizontal sand-ground undergoing lateral soil movement. We tried to find the property of row piles dependent on the shape of pile, including the position of the pile in row, pile spacing, and soil movement. The results of test are as follows. The lateral earth pressure diagram variously appeared to be triangle, trapezoid and rectangular by shape and position of pile. The outer pile has a larger bending moment than the inner pile in the case of B-type, the inner piles has larger one than outer pile in case of H-type. $R_f$ (the ratio of resistance to lateral soil movement) was found to increase with increasing pile spacing irrespective of pile-shape. Y/L (location of action of lateral resistance force) for $d_s$ (displacement of soil) and $S_h$ (spacing of pile) appeared to be nearly regular position, and H-type is higher than B-type.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.2
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• pp.140-145
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• 2018

This paper deals with the dynamical analysis of a two-point mooring vessel under surge excitations. The characteristics of nonlinear behaviors are investigated completely including bifurcation and limit cycle according to particular input parameter changes. The strong nonlinearity of the mooring system is mainly caused by linear and cubic terms of restoring force. The numerical simulation is performed based on the fourth order Runge-Kutta algorithm. The bifurcation diagram and several instability phenomena are observed clearly by varying amplitudes as well as frequencies of surge excitations. Stable periodic solutions, called the periodic windows, can be obtained in succession between chaotic clouds of dots in case of frequency ${\omega}=0.4rad/s$. In addition, the chaotic region is unexpectedly increased when external forcing amplitude exceeds 1.0 with the angular frequency of ${\omega}=0.7rad/s$. Compared to the cases for ${\omega}=0.4$, 0.7rad/s, the region of chaotic behavior becomes more fragile than in the case of ${\omega}=1.0rad/s$. Finally, various types of steady states including sub-harmonic motion, limit cycle, and symmetry breaking phenomenon are observed in the two-point mooring system at each parameter value.

• The Journal of the Petrological Society of Korea
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• v.26 no.4
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• pp.327-339
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• 2017

The Cretaceous Myeongseongsan Granite in the northwestern Gyeonggi Massif consists of a major pale pink-colored biotite monzogranite and a minor white-colored biotite alkaligranite. Low Sr and high Ba concentrations, negative Eu-anomalies in REE plot, negative Sr anomalies in spider diagram, a negative correlation between Sr and Rb, and positive correlations between Sr and Ba and $Eu/Eu^*$ indicate that a fractional crystallization of both plagioclase and K-feldspar played a significant role during magma evolution. The Myeongseongsan Granite is plotted in I-& S-type granites on I, S, A-type granite classification scheme. While the biotite monzogranite is plotted in unfractionated I-& S-type granite, the biotite alkaligranite is plotted in fractionated I-& S-type granite, which indicates that the biotite alkaligranite is a more differentiated product. In order to elucidate the nature of the protoliths of the peraluminous Myeongseongsan magma, we plotted in $Al_2O_3/TiO_2$ vs. $CaO/Na_2O$ and Rb/Sr vs. Rb/Ba diagrams, and they suggest that the Myeongseongsan Granite was derived from clay-poor metagreywackes and meta-psammites or their igneous counterparts. Whole-rock zircon saturation temperature indicates that the Myeongseongsan magma was melted at $740-799^{\circ}C$.

• Journal of Korean Philosophical Society
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• v.145
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• pp.381-407
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• 2018

Gilles Deleuze presents his distinctive logic of sensation in "Francis Bacon: The Logic of Sensation" with his own approach to Bacon's paintings. What matters here is the sensation of 'haptic' that is 'one possibility of the eyes' but different from optical perception. The concept of 'haptic' has been translated into Korean variously, and Gilles Deleuze adopted this concept from Austrian art historian, Alois Riegl. Alois Riegl had used the concept of 'haptic' to mean proximate view (Nahsicht in German) as in seeing Egyptian bas-relief. Gilles Deleuze was in succession to Alois Riegl's way of thinking and used the concept of 'haptic' to discuss Bacon's paintings. By the way, Alois Riegl had adopted this concept anyway to read Egyptian bas-reliefs, but Gilles Deleuze applies this concept to paintings. Actually, this concept in Gilles Deleuze's theory of painting has more meanings than Alois Riegl'. That is to say, when we intend to understand "The Logic of Sensation" as a new logic of sensation to be represented more than just a discussion about Bacon's paintings, we would say that key word is the concept of 'haptic' being symbolic of Bacon's paintings. Yet, what kind of sensation is the 'haptic'? And, what is Deleuze's theory of sensation? I want to interpret "Francis Bacon: The Logic of Sensation" as a work being developed through his own theory of sensation, and further more I should like to draw special attention to the sensation of 'haptic' in order to make his theory of sensation with admirable clarity.

• Journal of Korean Philosophical Society
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• v.141
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• pp.263-286
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• 2017

It is well known to us that in its enlarged sense Deleuze's philosophy has confrontation with platonism that has dominated the whole western ideas, and in a narrow sense it is confrontation with representative thinking and representative arts. In other words, it's obvious what Deleuze has considered the most important in his whole of ideas is to think not in a representative way but in a non-representational way and to disentangle thinking from its representative image. To examine the way how Deleuze criticize representation, and how he overcome modern ideas is not just to make a clean breast of platonic inheritance. Because they are essential for facing up to the actual circumstances of our contemporaries who have degraded servility of totalitarian thoughts under the thinking of identity, and furthermore, it is essential for overcoming this situation and proceeding to nomadic thinking, liberating thinking. This study is not intended to be a definitive account of all his criticism of representation. Because, as is well known, Deleuze's criticism of representation contains a wide variety. And so this study were limited a relatively small number of points in Deleuze's position on representation as follows. How does Deleuze's criticism of representation has been developed in his theory of paintings? And what does it mean to us today? In this paper, I paid special regard to make sense out Deleuze's concept of 'figure' in his important writings that pertains to an analysis of his criticism of representation, Francis Bacon: The Logic of Sensation. And having traced the development process of the concept of 'figure', I want to understand the implicit meaning of the concept in constant flux of his critical thinking.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.477-493
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• 2020

This study conducted a seasonal survey to analyze the spatio-temporal variations of marine environments and phytoplankton community in Gochang Coastal Waters (GCW) from August 2016 to April 2017. In the results, the water temperature ranged from 2.1℃ to 34.5℃, showing a large seasonal variation, but the salinity changed from 31.14 psu to 32.64 psu. Therefore, the seasonal variations of water types in GCW were mainly determined by water temperature. The phytoplankton community consisted of 53 genera and 86 species, showing a relatively simple distribution. The phytoplankton cell density ranged from 2.2 to 689.2 cells mL^-1, with an average of 577.2 cells mL^-1, which was low in autumn and high in winter. The seasonal succession of phytoplankton dominant species was mainly diatoms during the whole year, Leptocylindrus danicus, Chaetoceros curvisetus, Skeletonema costatum-ls in summer, Paralia sulcata, Eucampia zodiacus in autumn, S. costatum-ls, Thalassiosira nordenskioeldii in winter, and S. costatum-ls, Asterionella glacialis in spring. In other words, the phytoplankton community showed high diversity in GCW throughout the year. According to the PCA, GCW were easily heated and cooled by radiant energy at lower depth, and the seasonal distributions of phytoplankton were determined by the supply of nutrients by re-fuelling of surface sediments due to the seawater mixing such as tidal mixing.