• Journal of Sensor Science and Technology
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• v.31 no.3
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• pp.175-179
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• 2022

The physical properties of biomaterials are important for their isolation and separation from body fluids. In particular, the precise evaluation of the multi-physical properties of single biomolecules is essential in that the correlation between physical and biological properties of specific biomolecule. However, the majority of scientific equipment, can only determine specific-physical properties of single nanoparticles, making the evaluation of the multi-physical properties difficult. The improvement of analytical techniques for the evaluation of multi-physical properties is therefore required in various research fields. In this study, we developed a motion-tracking algorithm to evaluate the multi-physical properties of single-nanoparticles by analyzing their behavior. We observed the Brownian motion and electric-field-induced drift of fluorescent nanoparticles injected in a microfluidic chip with two electrodes using confocal microscopy. The proposed algorithm is able to determine the size of the nanoparticles by i) removing the background noise from images, ii) tracking the motion of nanoparticles using the circular-Hough transform, iii) extracting the mean squared displacement (MSD) of the tracked nanoparticles, and iv) applying the MSD to the Stokes-Einstein equation. We compared the evaluated size of the nanoparticles with the size measured by SEM. We also determined the zeta-potential and surface-charge density of the nanoparticles using the extracted electrophoretic velocity and the Helmholtz-Smoluchowski equation. The proposed motion-tracking algorithm could be employed in various fields related to biomaterial analysis, such as exosome analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.2
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• pp.187-195
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• 2022

This study investigated the effect of artesian pressure on mechanical properties of deep cement mixing (DCM)-improved specimens. Various laboratory tests such as unconfined compression test and scanning electron microscope (SEM) were conducted on DCM specimens which curied in a water tank with different artesian pressures. The artesian pressure was determined in consideration of the laboratory scale and the hydraulic gradient in field conditions. Results of experimental tests indicated that unconfined compressive strength, secant modulus, and unit weight of specimen decreased and water content tended to increase as an artesian pressure increased. The stress-strain behavior changed brittle to ductile behaviors as an artesian pressure increased. The outflow water from the water tank reacted with the phenolphthalein solution due to the leaching phenomenon of the improved specimen. SEM analysis also confirmed that a small amount of ettringite was formed between soil particles in the specimens with artesian pressure.

• Korean Journal of Materials Research
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• v.32 no.2
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• pp.57-65
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• 2022

Herein a rich, Se-nanoparticle modified Mo-W₁₈O₄₉ nanocomposite as efficient hydrogen evolution reaction catalyst is reported via hydrothermal synthesized process. In this work, Na₂SeSO₃ solution and selenium powder are used as Se precursor material. The structure and composition of the nanocomposites are characterized by X-ray diffraction (XRD), high-resolution field emission scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), EDX spectrum analysis and the corresponding element mapping. The improved electrochemical properties are studied by current density, and EIS analysis. The as-prepared Se modified Mo-W₁₈O₄₉ synthesized via Na₂SeSO₃ is investigated by FE-SEM analysis and found to exhibit spherical particles combined with nanosheets. This special morphology effectively improves the charge separation and transfer efficiency, resulting in enhanced photoelectric behavior compared with that of pure Mo-W₁₈O₄₉. The nanomaterial obtained via Na₂SeSO₃ solution demonstrates a high HER activity and low overpotential of -0.34 V, allowing it to deliver a current density of 10 mA cm^-2.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.3
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• pp.889-899
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• 2017

Various efforts and technical development for integrating the ICT technologies to the area of special needs education have been continuing. In this paper we have studied and implemented various ICT-based disability evaluation websites and mobile applications for special needs education and also verified their usefulness from the field test at disability schools. The valuer can access the websites and mobile applications for autistic behavior or learning disability evaluation at the any places and by any devices such as laptop, PC, smartphone and tablet PC. And all the evalation results are stored into and managed at the server database and shared with websites and mobile applications to integrate together easily. From the study about disability evaluation and implementation results we have a confidence that they will be useful to support the seamless evaluation and the continuous monitoring services for the disabled at the special needs education fields.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.240-243
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• 2021

Recently, there have been research results of applying Big data and AI technologies to the evaluation and individual learning for education. It is information technology innovations that collect dynamic and complex data, including student personal records, physiological data, learning logs and activities, learning outcomes and outcomes from social media, MOOCs, intelligent tutoring systems, LMSs, sensors, and mobile devices. In addition, e-learning was generated a large amount of learning data in the COVID-19 environment. It is expected that learning analysis and AI technology will be applied to extract meaningful patterns and discover knowledge from this data. On the learner's perspective, it is necessary to identify student learning and emotional behavior patterns and profiles, improve evaluation and evaluation methods, predict individual student learning outcomes or dropout, and research on adaptive systems for personalized support. This study aims to contribute to research in the field of education by researching and classifying machine learning technologies used in anomaly detection and recommendation systems for educational data.

• Journal of Music and Human Behavior
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• v.19 no.2
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• pp.1-26
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• 2022

This review was conducted to identify the research trends in music intervention studies with elderly patients with dementia. Korean- and English-written studies on music intervention for this population were searched and analyzed. Seventeen studies were included in the final analysis. The results showed that behavioral and psychological symptoms were the main dependent variables. In terms of the type of music intervention employed, interventions requiring the patient's active participation in producing music were more common than interventions that required the patient to only listen to music. The majority of studies provided live music, selected music that was familiar to and preferred by the patient, and utilized rhythm-based performance activities. In the studies using active music production as the intervention, the participants were asked to express the emotions evoked by group instrument playing or singing along with music, which doesn't reflect the functional limitations (e.g., cognitive impairment) of elderly patients with moderate to severe dementia. The results of this review point to the need in the field to develop music intervention programs for the elderly with moderate to severe dementia that meaningfully engage these patients in music-related behaviors that target their specific symptomology.

• Geomechanics and Engineering
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• v.33 no.6
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• pp.583-596
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• 2023

The interlayers, either softer or stiffer than the surrounding layers, are usually overlooked during field investigation due to the small thickness. They may be neglected through the analysis process for simplicity. However, they may significantly affect the dynamic behavior of the soil-foundation system. In this study, a series of 3D finite-element Direct-solution steady-state harmonic analyses were carried out using ABAQUS/CAE software to investigate the impacts of interlayers on the dynamic response of a cast in place pile group subjected to horizontal harmonic load. The experimental data of a 3×2 pile group testing was used to verify the numerical modeling. The effects of thickness, depth, and shear modulus of the interlayers on the dynamic response of the pile group are investigated. The simulations were conducted on both stiff and soft soils. It was found that the soft interlayers affect the frequency-amplitude curve of the system only in frequencies higher than 70% of the resonant frequency of the base soil. While, the effect of stiff interlayer in soft base soil started at frequency of 35% of the resonant frequency of the base soil. Also, it was observed that a shallow stiff interlayer increased the resonant amplitude by 11%, while a deep one only increased the resonant frequency by 7%. Moreover, a shallow soft interlayer increased the resonant frequency by 20% in soft base soils, whereas, it had an effect as low as 6% on resonant amplitude. Also, the results showed that deep soft interlayers increased the resonant amplitude by 17 to 20% in both soft and stiff base soils due to a reduction in lateral support of the piles. In the cases of deep thick, soft interlayers, the resonant frequency reduced significantly, i.e., 16 to 20%. It was found that the stiff interlayers were most effective on the amplitude and frequency of the pile group.

• Journal of the Korean Geotechnical Society
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• v.39 no.1
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• pp.27-38
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• 2023

In this study, the impact of pile tip geometry, including shape, size, and angle, on the drivability and stress concentration during pile driving was investigated using 3D printing technology and finite element numerical analysis. A series of field loading tests were conducted on a test pile with various pile tip conditions, including width, angle, and shape. The changes in settlement were quantified as a ratio to the settlement of a conventional pile tip case and large deformation finite element analysis was used to investigate the maximum stress on a pile tip and the location of possible damage during pile driving. The results showed that by modifying the shape, size, and angle of the pile tip, the drivability of the pile could be improved and the maximum stress concentration around the pile tip could be significantly reduced, thereby ensuring the structural integrity of the pile during pile driving.

• Communications of Mathematical Education
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• v.37 no.1
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• pp.21-45
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• 2023

This study presents a machine learning program designed to identify impactful papers in the field of mathematics education. To achieve this objective, we examined the impact of papers from a scientific econometrics perspective, developed a mathematics education research network, and defined the impact of mathematics education research using PageRank, a network centrality index. We developed a machine learning model to determine the impact of mathematics education research and identified the journals with the highest percentage of impactful articles to be the Journal for Research in Mathematics Education (25.66%), Educational Studies in Mathematics (22.12%), Zentralblatt für Didaktik der Mathematik (8.46%), Journal of Mathematics Teacher Education (5.8%), and Journal of Mathematical Behaviour (5.51%). The results of the machine learning program were similar to the findings of previous studies that were read and evaluated qualitatively by experts in mathematics education. Significantly, the AI-assisted impact evaluation of mathematics education research, which typically requires significant human resources and time, was carried out efficiently in this study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3D
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• pp.435-444
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• 2006

This paper investigates the effect of 3-dimensional FE models to evaluation results of jointed concrete pavements which is back-calculated by AREA method. Sensitivity of 3-dimensional FE models developed to simulate the behavior of real jointed concrete pavement are analyzed after compared with 2-dimensional FE models using ILLISLAB. In comparison with 2-dimensional models, influence of concrete contraction under loading plate and base layer on surface deflections is more than that of loading configuration. Deflections at 3-dimensional model between linear and nonlinear temperature distribution under same temperature difference are similar, but noticeable differences are investigated in low elastic modulus of foundations. Dynamic deflections under loading plate are larger than static deflections in high elastic modulus of foundation, but smaller in low elastic modulus. Lower dynamic modulus of subgrade reactions are backcalculated by dynamic deflections than by static deflections. But reverse trend is investigated in the backcalculated elastic modulus of concrete which describes trends of the field backcalculation values calculated from AREA method.