• Textile Coloration and Finishing
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• v.17 no.1
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• pp.45-51
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• 2005

Soluble keratose(S-keratose) could be obtained by oxidizing the wool keratin with performic acid. S-keratose/PVA solutions were made by dissolving them in the formic acid and S-keratose/PVA web of sub-micron size was made by electro-spinning technique. SEM, elemental analysis, FT-IR, X-ray diffractometry, and TGA were used to characterize the properties of S-keratose/PVA solutions and fibers. As the S-keratose content in S-keratose/PVA solution increased, viscosity of solution decreased while electrical conductivity has increased. The fiber diameter has decreased with increasing the S-keratose content. S-keratose/PVA ratio in fibers were similar to the ratio in the solutions. The crystalline structures of S-keratose and PVA existed separately in the electrospun webs. Thermal stability of the web increased with the PVA content increasing.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.12
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• pp.1083-1087
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• 2005

As development of digital technology, many kinds of multimedia data are used variously and requirements for effective use by user are increasing. In order to transfer information fast and precisely what user wants, effective retrieval method is required. As existing multimedia data are impossible to apply the MPEG-1, MPEG-2 and MPEG-4 technologies which are aimed at compression, store and transmission. So MPEG-7 is introduced as a new technology for effective management and retrieval of multimedia data. In this paper, we extract content-based features using color descriptor among the MPEG-7 standardization visual descriptor, and reduce feature data applying PCA(Principal Components Analysis) technique. We model the cerebral cortex and hippocampal neural network in engineering domain, and team content-based feature vectors fast and apply the hippocampal neural network algorithm to compose of optimized feature. And then we present fast and precise retrieval effect when indexing and retrieving.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.371-374
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• 2002

Bismuth lanthanum titanate thin films with excess Bi contents were prepared onto Pt/Ti/$SiO_2$/Si substrate by metalorganic decomposition (MOD) technique. The structure and morphology of the films were analyzed using X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. From the XRD analysis, BLT thin films show polycrystalline structure and the layered-perovskite phase was obtained over 10% excess of Bi contents. As a result of ferroelectric characteristics related to the Bi content of the BLT thin film, the remanent polarization and dielectric constant decreased with increasing over Bi content of 10 % excess. The BLT film with Bi content of 10% excess was measured to have a dielectric constant of n9 and dielectric loss of 1.85[%]. The BLT thin films showed little polarization fatigue test up to 3.5 x $10^{9}$ bipolar switching cycling.

• Journal of Korea Multimedia Society
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• v.25 no.3
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• pp.476-492
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• 2022

This study explored at the potentials of exhibition appreciation classes using the metaverse platform, and identified what types of interactions could occur when elementary students participate in the exhibition appreciation education using metaverse platform. We had a user observation research and FGI through implementation of actual elementary class and we analyzed problematic experiences from the viewpoint of user to content and user to user interaction. As a result, fifteen UX improvements were derived by Delphi technique for solving the problematic experiences and improving learner's interactivity.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.77-84
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• 2024

Aberration is still a problem for making augmented reality displays. The existing methods to solve this problem are either slow and inefficient, consume too much battery, or are too complex for straightforward implementation. There are still some problems with image quality, and users may suffer from eye strain and headaches because the images provided to each eye lack accuracy, causing the brain to receive mismatched cues between the vergence and accommodation of the eyes. In this paper, we implemented a computer simulation of an optical aberration using Zernike polynomials which are defocus, trefoil, coma, and spherical. The research showed that these optical aberrations impact the Point Spread Function (PSF) and Modulation Transfer Function (MTF). We employed the phase conjugate technique to mitigate aberrations. The findings revealed that the most significant impact on the PSF and MTF comes from the influence of spherical aberration and coma aberration.

• Journal of Korean Library and Information Science Society
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• v.12
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• pp.61-96
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• 1985

The human subject analysis of a document has some critical problems. The method results in the inconsistency in analysis process and the contradiction of two objects of the subject analysis (one is the identification of the content for the retrieval of specific items and the other is to identify the content for the grouping of related materials). Since the subject analysis by mechanized has been recognized to be the possible way to aggregate the problems of manual analysis, various a n.0, pproaches of automatic indexing have been studied and experimented. This study is to examine the automatic indexing as one of the promising subject analysis techniques by statistical, syntactical and semantic a n.0, pproaches. In conclusion, the reasonable a n.0, pplication time of the automatic indexing should be made a decision based on the through investigation on the cost verse effectiveness, and automatic indexing system should be developed in the close relationship with the on-line search which is a good retrieval system for information explosion society. From now on, since the machine-readable document-text will be envisaged to be more and more available due to the rapid development of computer technology, the more substantial research on the automatic indexing will be also possible, which can bring about the increasing of practical automatic indexing systems.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.6
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• pp.1535-1541
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• 1994

The void content of carbon fiber reinforced composite laminates was determined by the ultrasonic nondestructive technique. The ultrasonic immersion, through-transmission method developed stresses the utilization of spectral analysis and frequency dependence of the attenuation due to porosity. The measured attenuation shows approximately linear behavior over the frequency range investigated. The linear relationship between the void content and the attenuation slop (d $\alpha$/df) is found to hold, but the constant of proportionality is quite different for samples with different pore morphology. The void volume fraction determined by the attenuation slope agreed very well with that obtained by the acid digestion analysis.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.4
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• pp.51-57
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• 2006

This study was carried out to investigate the soil water characteristic curve and prediction of void ratio with net stress and matric suction using the linear elastic and volumetric deformation analysis method on unsaturated silty. The unsaturated soil tests were conducted using a modified oedometer cell and specimens were prepared at water content 2 times of liquid limit and required void ratio. The axis translation technique was used to create the desired matric suctions in the samples. It is shown that soil water characteristic curve and volumetric water content were affected significantly by preconsolidation pressure. As a matric suction increases, the reduction ratio of void ratio was shown to considerably small. Also, the predicted and measured void ratio for unsaturated soils using the linear elastic and volumetric deformation analysis showed good agreement as net stress and matric suction increases.

• Journal of the Korean Ceramic Society
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• v.54 no.2
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• pp.102-107
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• 2017

The dependence of the IR optical properties of PMMA/$Al_2O_3$ nanocomposite on the alumina content was investigated in the wavelength range of $3500-2800cm^{-1}$. The samples were prepared via emulsion polymerization technique using oleic acid as a coupling agent. Grafting density calculations were carried out by means of elemental analysis CHN to yield the best coupling agent content. FTIR analysis confirmed the existence of a chemical bond between aluminum oxide and oleic acid. The outcomes of XRD analyses showed the presence of cubic gamma aluminum oxide in the nanocomposite, in contrast to the amorphous nature of PMMA. TEM images showed the core-shell morphology of the particles other than pristine PMMA. Optical constants of the nanocomposite were calculated based on FTIR spectra and the Kramers-Kronig equations. The presence of nano alumina modified some of the optical indexes in IR region.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.52-57
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• 2022

In this study, keywords from representative online portal sites such as Naver, Google, and Youtube were collected based on text mining analysis technique using Textom to check the changes in metqaverse after COVID-19. before Corona, it was confirmed that social media platforms such as Kakao Talk, Facebook, and Twitter were mentioned, and among the four metaverse, consumer awareness was still concentrated in the field of life logging. However, after Corona, keywords from Roblox, Fortnite, and Geppetto appeared, and keywords such as Universe, Space, Meta, and the world appeared, so Metaverse was recognized as a virtual world. As a result, it was confirmed that consumer perception changed from the life logging of Metaverse to the mirror world. Third, keywords such as cryptocurrency, cryptocurrency, coin, and exchange appeared before Corona, and the word frequency ranking for blockchain, which is an underlying technology, was high, but after Corona, the word frequency ranking fell significantly as mentioned above.