• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.10
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• pp.38-43
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• 2021

Photocurable hydrogels are widely used as 3D printing materials in tissue engineering (e.g., scaffold fabrication) as well as optical fibers (or optical sensors) materials. Photocurable hydrogels can control optical and mechanical properties such as chemical or fabrication conditions. In previous research, we introduced a new 3D printing method to fabricate a freestanding overhanging hydrogel structure without supporting structure. This study was measured and analyzed the difference of the mechanical properties of the photocurable hydrogel according to the light intensity using a micro tensile tester. In practically, it was difficult to perform a direct tensile test on a micro (less than 1 mm) size fiber. In this study, the tensile test of the hydrogel fibers could be measured simply and repeatedly using a paper carrier.

• International Journal of Computer Science & Network Security
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• v.21 no.12spc
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• pp.657-663
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• 2021

The main purpose of the study is to analyze the information aspects of the impact of COVID-19 on the labor market in the EU and Ukraine. In addition to studying the key parameters of changes in the labor market under the influence of COVID-19, i.e. the unemployment rate and the share of the employed population, a thorough study of gender equality, labor migration and the impact on youth made it possible to characterize the effectiveness of the policy of stabilization and restoration of the labor market in the EU and Ukraine. The results obtained form the necessary information basis for modeling labor market regulation in the event of possible subsequent disturbances, in particular under the influence of global pandemics.

• Journal of Korean Library and Information Science Society
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• v.4
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• pp.61-90
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• 1977

The historical development of books examination with utilizing science become inevitable to the machanization of library catalogues. With the advance of times, like this, a new- development of $Indention('||'&'||'$ : Kisun) must be sought for which is a kind of descriptive catalogues being used now. This paper is scheduled to grasp problems in the course of using and logical grounds of Indention which hal-e been used disordering. It must be considered that four kinds of Icdention settlement is suitable to the features of Korean letters. 1) TI-e must consider the features of Korean Language and Oriental Language writing(Japan, China). There must be a establishment of floating $Indention('||'&'||'E$ : Kisun), which are suitable for the writting style or hand writting man on the point of most of Koreans are depend upon hand witting, then books catalogues like western language, not left edge of the cards of the $Indention(B$ : Kisun) establishing, from edge to Call Number, from the last of the Call Number to First Indention(%-Bl63). First Indention(%-%%) to a space of Second $indention($\ulcorner^%)$ must be established and then, every catalogue and Indentions are distinguished surely. 2) \Then we consider the developing catalogue making in the future. It is important to establish a fixed $Indention('||'&'||'$ : Kisun) for machinization of typewriter(Korean, Mimeographing) and computer, etc ... not "Cm" unit but "Space" unit, and consider oriental letter, ne make more surplus space as a Indention, we can give anadaptablity of using machines. 3) Considering typography printing and type-setting printing by printing type, we must fit the $Indention(\ulcorner'||'&'||'$ : Kisun) as a "Cm" unit, and there must be a re-adjustment of $Indention(g$$ : Kisun) which considered the complexity of Call Number by a mass of collecting books like this, the establishment of Indention(E'||'&'||'j!: Kisun). We must not use a uilified one as a concrete conception by "Space" or "Cm" unit which has been used now but re-adjusted adaptably which can be fited as a method of making of catalogues. 4) The name of $Indcntion(J, S$ : Kisun) has becll called 7;arious methods until now, but English Indention which has been used without any concrete mexirig must be used as a ours fitable as a our mind. The above mentioned is presented as a Indention and examinational l~letilods by myself style, I wants these r i l l be helpful to the future developments of the machanization of Indention $(sf:$ Ki sun). Concrete studies must be continued in the future for development of $Indention(zj:$ : Kisun). : Kisun).

• Communications of Mathematical Education
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• v.28 no.3
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• pp.353-366
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• 2014

Recently, the widespread usage of 3D-Printing has grown rapidly in popularity and development of a high level technology for 3D-Printing has become more necessary. Given these circumstances, effectively using mathematical knowledge is required. So, we have developed free web tools for 3D-Printing with Sage, for mathematical 3D modeling and have utilized them in college education, and everybody may access and utilize online anywhere at any time. In this paper, we introduce the development of our innovative 3D-Printing environment based on Calculus, Linear Algebra, which form the basis for mathematical modeling, and various 3D objects representing mathematical concept. By this process, our tools show the potential of solving real world problems using what students learn in university mathematics courses.

• Journal of the Optical Society of Korea
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• v.15 no.3
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• pp.310-317
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• 2011

Perceptibility and acceptability are the most often used threshold units in the field of color science. The former refers to a just perceptible difference and the latter evokes a tolerable color difference. Such thresholds can be very significant to color quality control processes in the printing industry and should be defined in quality measure units. Optical density (OD) and color difference models are usually utilized as color quality measures and have been provided in a considerable number of commercial measuring devices such as spectrophotometers. However, their merits and traits are far less understood in the literature. The present study intends to evaluate performance of those color quality measures including the OD and widely known color difference models, e.g. ${\Delta}E{^*}_{ab}$, ${\Delta}E_{CMC(l:c)}$ and ${\Delta}E{^*}_{00}$. A set of psychophysical assessments were carried out in order to accumulate the perceptibility and acceptability thresholds data, and their central trend was compared with the color quality measure estimates.

• Proceedings of the CALSEC Conference
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• 2001.08a
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• pp.523-532
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• 2001

Despite the social interest in eBook and its advantages, as a result of each industry using different document formats, it is difficult to exchange or share eBook contents. And this hindered the activation of eBook market. The U.S. and Japan have realized the importance of setting a standard for eBook document format and have established eBook standard with government agencies and related industries and in Korea, also, through Working Group for Standardization Committee of EBK, eBook industry standard, EBKS, was established. EBKS provides more advantages than HTML or PDF and the basic format is XML. The objective of EBKS is exact exchange of eBook content, reflection of characteristics of Korean publication environment, simplicity in creating, and convertibility with other standards. Meanwhile, in the DTD aspect, EBKS includes static document structure, extension mechanism, vertical writing, multi-column editing and reflection on the characteristics of Korean and proverbs. For exchanging style, content and style are separated using XSL-FO and XSL-FO is recommended for printing. Also, EBKS metadata is composed of do-metadata that does not use qualifier and x-metadata for extension to provide easiness in usage and ability to exchange and convert.

• Journal of Information Display
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• v.2 no.3
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• pp.48-53
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• 2001

Carbon nanotube emitters, prepared by screen printing, have demonstrated a great potential towards low-cost, largearea field emission displays. Carbon nanotube paste, essential to the screen printing technology, was formulated to exhibit low threshold electric fields as well as an emission uniformity over a large area. Two different types of triode structures, normal gate and undergate, have been investigated, leading us to the optimal structure designing. These carbon nanotube FEDs demonstrated color separation and high brightness over 300 $cd/m^2$ at a video-speed operation of moving images. Our recent developments are discussed in details.

• Journal of the Korean Ceramic Society
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• v.38 no.10
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• pp.948-952
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• 2001

PZT thick films were fabricated on alumina substrates by a screen printing method. They were sintered at $750^{\circ}C{\sim}1050^{\circ}C$ for 1 h under air or Pb atmosphere. Pyrochlore was observed as a second phase in PZT thick films sintered in air at temperatures of $950^{\circ}C$ and higher. PZT thick films sintered under Pb atmosphere showed denser microstructure, higher dielectric constant, and better-developed P-E hysteresis curve than the films sintered in air. PZT thick films sintered at $900^{\circ}C$ under Pb atmosphere showed the typical ferroelectric hysteresis with remanent polarization of $29.8{\mu}C/cm^2$ and coercive field of 48.4 kV/cm.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.2
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• pp.48-55
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• 2022

The color image of the brand comes first and is an important visual element that leads consumers to the consumption of the product. To express more effectively what the brand wants to convey through design, the printing market is striving to print accurate colors that match the intention. In 'offset printing' mainly used in printing, colors are often printed in CMYK (Cyan, Magenta, Yellow, Key) colors. However, it is possible to print more accurate colors by making ink of the desired color instead of dotting CMYK colors. The resulting ink is called 'spot color' ink. Spot color ink is manufactured by repeating the process of mixing the existing inks. In this repetition of trial and error, the manufacturing cost of ink increases, resulting in economic loss, and environmental pollution is caused by wasted inks. In this study, a deep learning algorithm to predict printed spot colors was designed to solve this problem. The algorithm uses a single DNN (Deep Neural Network) model to predict printed spot colors based on the information of the paper and the proportions of inks to mix. More than 8,000 spot color ink data were used for learning, and all color was quantified by dividing the visible light wavelength range into 31 sections and the reflectance for each section. The proposed algorithm predicted more than 80% of spot color inks as very similar colors. The average value of the calculated difference between the actual color and the predicted color through 'Delta E' provided by CIE is 5.29. It is known that when Delta E is less than 10, it is difficult to distinguish the difference in printed color with the naked eye. The algorithm of this study has a more accurate prediction ability than previous studies, and it can be added flexibly even when new inks are added. This can be usefully used in real industrial sites, and it will reduce the attempts of the operator by checking the color of ink in a virtual environment. This will reduce the manufacturing cost of spot color inks and lead to improved working conditions for workers. In addition, it is expected to contribute to solving the environmental pollution problem by reducing unnecessarily wasted ink.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.275-276
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• 2008