• Elastomers and Composites
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• v.57 no.3
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• pp.100-106
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• 2022

Waterborne polyurethane-acrylate(WPUA) dispersions were prepared by surfactant-free emulsion polymerization in a two-step process. In the first step, polytetrahydrofuran, isophorone diisocyanate, dimethylol proponic acid, and 2-hydroxyethyl methacrylate were used to synthesize a vinyl-terminated polyurethane prepolymer. In the second step, styrene, methyl methacrylate, butyl acrylate, and different multi-functional crosslinkers were copolymerized. 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, and pentaerythritol tetraacrylate were used as the crosslinkers, and their effect on the mechanical and thermal properties of WPUA was investigated. Overall, as the number of functional groups of the cross-linker increased, the gel fraction improved to 79.26%, the particle size increased from 75.9 nm to 148.7 nm, and the tensile strength was improved from 5.86 MPa to 12.40 MPa. In thermal properties, the glass transition temperature and decomposition temperature increased by 9.9℃ and 18℃, respectively. The chemical structures of the WPUA dispersions were characterized by Fourier-transform infrared spectroscopy. The synthesized WPUA has high potential for applications such as coatings, leather coatings, adhesives, and wood finishing.

• Journal of the Korea Society of Computer and Information
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• v.28 no.11
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• pp.21-28
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• 2023

In manufacturing companies that focus on small-scale production of multiple product varieties, defective products are manually selected by workers rather than relying on automated inspection. Consequently, there is a higher risk of incorrect sorting due to variations in selection criteria based on the workers' experience and expertise, without consistent standards. Moreover, for non-standardized flexible objects with varying sizes and shapes, there can be even greater deviations in the selection criteria. To address these issues, this paper designs a quality inspection system using artificial intelligence-based unsupervised learning methods and conducts research by experimenting with accuracy using a dataset obtained from real manufacturing environments.

• Korean Journal of Mathematics
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• v.6 no.2
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• pp.331-339
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• 1998

We show a series of improved subseries convergence results, e.g., in a sequentially complete locally convex space X every weakly $c_0$-Cauchy series on X must be $c_0$-convergent. Thus, if X contains no copy of $c_0$, then every weakly $c_0$-Cauchy series on X must be subseries convergent.

• Journal of Korea Technology Innovation Society
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• v.18 no.4
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• pp.693-718
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• 2015

This paper examines the presence of network structures among convergence technologies focusing on national R&D projects performed by GRIs(Government-sponsored Research Institutes) in Korea. The dataset of convergence technology projects, which were conducted by 24 GRIs over 3 years (2011-2013), are analysed using the network analysis method. In this paper, a convergence technology project is defined as a project that consists of 2 or more then 2 technologies according to the intermediate classification of National Standard Classification of S&T. The research results confirm that convergence researches of government-sponsored research institutes are performed more actively than the entire convergence researches of national R&D projects. Furthermore, technological fields of GRIs' convergence projects are found to be much more varied. This paper also shows that in-house researches are more active than collaborative ones with external organizations. According to the network centrality analysis, it is identified that the network central characteristics of convergence technologies can be classified into internally oriented technologies and externally oriented technologies. Convergence technologies do not just mean simple mixture of different technologies. Therefore Korean government-sponsored research institutes should make more efforts to create convergence research areas which could generate new technologies and industries more effectively than simple multidisciplinary technology researches. From this perspective, some policy suggestions can be derived on the role of government-sponsored research institutes for activating convergence researches through the analysis of status of convergence researches and networks of institutions.

• Journal of Engineering Education Research
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• v.15 no.6
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• pp.92-97
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• 2012

This paper deals with the model of natural sciences and engineering's convergence education. Recently, convergence education's necessary is needed since the most of new products are designed and produced based on the convergence technology. But our country's education system is keeping existing education process. This make industrial world undurable to employ the current graduated students. Also in view of educational world, they have no proper convergence education model for their students. In this paper, to solve the non-existing convergence education model, we derive the a few convergence education model and list up their model each. This result will be helpful for the introducer of the convergence education system.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.669-670
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• 2006

This paper describes the functions and design technology of the T-DMB (Terrestrial Digital Multimedia Broadcasting) receiver. T-DMB is a novel broadcasting media that can provide high-quality video and audio services. In this paper, we will describe the VLSI implementation of RF, Baseband and Multimedia Chip for T-DMB Receiver. The designed DMB SoC has low power consumption and has been implemented using a standard-cell library in 0.18um CMOS technology.

• International Journal of Contents
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• v.12 no.3
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• pp.54-58
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• 2016

In this study, articles of the science and technology field that had been monitored for the period from 2002 to 2013 using GTB (Global Trends Briefing) were analyzed. Specifically, the VOSviewer was used to analyze the annual science and technology trends by keyword and the science and technology standard-classification information indicated in the GTB articles, and the convergence trends were therefore monitored. The findings of this study show that active studies were under way in the fields of material science and new and renewable energy, and that convergence has progressed. This result indicates that the information of the articles on papers and patents is more reliable, as it can reflect the current trends more rapidly in the science and technology field than the paper information or the patent information that is traditionally used in analyses of science and technology information.

• Composites Research
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• v.29 no.4
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• pp.216-222
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• 2016

Ring-opening metathesis polymerization of p-dicyclopentadiene (DCPD) can be performed using the tungsten type catalyst. This reaction usually progresses in nitrogen condition, because the catalysts are extremely sensitive in air condition. To solve this problem, DCPD resin with tungsten (W) was cured using hot press after stirring of DCPD A and B liquid in air condition. Mechanical properties of DCPD were improved by reducing microvoid occurrence successfully by using hot press method. It might be because hot press could provide sufficient press on DCPD specimen. Addition of catalyst was not effective for the curing of resin in a short time. During polymerization, pressure and temperature had a great influence on the mechanical properties of DCPD.

• Composites Research
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• v.29 no.4
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• pp.125-131
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• 2016

In case of CNT mixing with epoxy, epoxy matrix needs to be diluted. This work studied the effect of the dilution condition of epoxy on CNT dispersion. The optimum solvent condition using acetone and DMF was found via mechanical and solubility methods which affects, the epoxy performance. The dispersion using acetone was better than the DMF and thus higher mechanical properties. Four mixing types of CNT particle were performed. To verify the effects of each step between dilution and dispersion, the dispersion between epoxy and CNT was evaluated via the electrical resistance and optical methods. The optimum dispersion was obtained via mechanical test and thermal analysis by DSC. Among four types, the best was to disperse CNT after epoxy and hardeners were diluted respectively.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.3
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• pp.453-461
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• 2020

In this study, we conducted technology monitoring to search for the current technology level and new technologies targeting the core technologies selected as "convergence technologies based on advanced ICT". This technology group, selected by the National Research Foundation(NRF) as one of the future-emerging technologies in 2018, consists of 'next-generation millimeter wave wireless communication technology', 'data-centric computing technology', and 'immersive media interface' that can be seen as important technologies in the fourth industrial revolution. It is possible to provide strategic research direction to the R&D-related stakeholders of countries or enterprises by providing information on newly emerged technologies through quantitative analysis based on patent data on these technologies. Therefore, in this study, we proposed a new technology for the convergence technologies based on advaned ICT group through patent data based on the newly emerged IPC code, and also suggested that it can suggest a strategic direction in planning R&D on related technologies.