• ETRI Journal
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• v.28 no.5
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• pp.555-560
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• 2006

A PIN photodiode having a low dark current of 1.35 nA and a high external quantum efficiency of 95.3% fabricated for a passive optical network receiver. As the current was increased under a high voltage of 38 V and a temperature of $190^{\circ}C$, it was observed that there is a threshold current at 11 mA which induces a junction failure. Experimental data suggest that the junction failure occurs due to the crystal breaking at the end facet as a result of thermal heat or energetic carriers. This threshold behavior of junction failure is a valuable observation for the safe treatment of photodiodes. As long as the current is limited below the threshold currents, we have not observed failure events of our photodiodes.

• Korean Journal of Optics and Photonics
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• v.32 no.5
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• pp.220-229
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• 2021

The optical characteristics of high-power direct-lit white light-emitting diode (LED) lighting were investigated, where a quantum dot (QD) film was adopted to enhance the color-rendering index (CRI). The transmittance of the diffuser plate and the concentration of the QD film were varied in this study. The color coordinates and the correlated color temperature (CCT) did not show any appreciable change, while the CRI values increased slightly as the transmittance of the diffuser plate decreased. The investigated optical properties were nearly independent of the viewing angle, and the luminance distribution was close to Lambertian. The CCT decreased from approximately 6000 K to approximately 4000 K as the concentration of the QD film increased from 0 to 7.5 wt%, which was due to the enhanced red component in the emission spectrum. The CRI increased to approximately 95 for some optical configurations of the lighting. These results demonstrate that glare-free, color-changeable, high-rendering LED lighting can be realized by using a combination of a diffuser plate of appropriate transmittance and a red QD film.

• The Pure and Applied Mathematics
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• v.14 no.1 s.35
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• pp.15-21
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• 2007

We introduce the notion of pre-convergence of p-stacks and characterize the pre-interior, pre-closure, separation axioms and pre-continuity on a topological space by using pre-convergence of p-stacks. We also introduce the notion of p-precompactness and investigate its properties in terms of pre-convergence of p-stacks.

• Toxicological Research
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• v.35 no.4
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• pp.395-402
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• 2019

Subcutaneous adipose tissue (SAT) accumulation is a constitutional disorder resulting from metabolic syndrome. Although surgical and non-surgical methods for reducing SAT exist, patients remain non-compliant because of potential adverse effects and cost. In this study, we developed a new minimally-invasive approach to achieve SAT reduction, using a microneedle (MN) patch prepared from gelatin, which is capable of regulating fat metabolism. Four gelatin types were used: three derived from fish (SA-FG, GT-FG 220, and GT-FG 250), and one from swine (SM-PG 280). We applied gelatin-based MN patches five times over 4 weeks to rats with high-fat diet (HD)-induced obesity, and determined the resulting amount of SAT. We also investigated the histological features and determined the expression levels of fat metabolism-associated genes in SAT using hematoxylin and eosin staining and western blotting, respectively. SAT decreased following treatment with all four gelatin MN patches. Smaller adipocytes were observed in the regions treated with SA-FG, GT-FG 250, and SM-PG 280 MNs, demonstrating a decline in fat accumulation. The expression levels of fat metabolism-associated genes in the MN-treated SAT revealed that GT-FG 220 regulates fatty acid synthase (FASN) protein levels. These findings suggest that gelatin MN patches aid in decreasing the quantity of unwanted SAT by altering lipid metabolism and fat deposition.

• Journal of Korea Technology Innovation Society
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• v.22 no.3
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• pp.446-474
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• 2019

In conjunction with securing R&D competitiveness through technology convergence, there is a growing interest in the strategy to derive innovation based on the measurement of convergence. In this paper, we present a data-based model that suggests convergence strategies for the research projects of government research institutes (GRIs) in Korea. The convergence characteristics of the research projects are represented by inherent attributes of technology and behavioral attributes of actors. The measuring process of the proxy variables (Rao-Stirling and Herfindahl-Hirschman Indices) for each attributes are proposed. These two indices are used to construct the convergence diagram, through which the research projects of GRIs are distributed into four areas: AllianceIntra, Alliance-Inter, Competition, Mission-Oriented. Based on the convergence diagram proposed in this study the convergence index is measured to derive 30 convergence research areas of GRIs. As a result, we expect to provide appropriate guidelines for setting the policy direction of the convergence research projects.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.4_2
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• pp.683-691
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• 2020

In the era of super-aged societies, research and development (R&D) projects related to aging are very important agenda for establishing the direction of future R&D planning and technological competitiveness in the country. In order to respond promptly to this agenda, it is essential to establish a national-level convergence R&D policy. In this study, we utilized the global R&D funding project data from major nations (US, Europe, Japan), and then standardized them with the same fields. To analyze the current status of global R&D related to aging, we performed cluster analysis based on the co-occurrence matrix to explore convergence R&D areas in the US, Europe, and Japan related to aging. In addition, comparative analysis by country suggested that different points on the interdisciplinary area and the convergence of aging-related R&D by each country. These results provide fundamental understandings for the status of convergence in aging-related global R&D, the current technology trends, and establish the direction and strategy of R&D policy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.7
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• pp.1235-1241
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• 2007

Convergence being process varietly and quickly, with complex products and services based on digital technology and with start its creating new form of products and service, influenced to diversity of consumers need, and social trend. Thus, in this paper, convergence it presents the application instance according to variation of the convergence commit, and observed the advantage which is the possibility of appearing from here, it has the necessity of the effect and the policy preparatio, appearing on it try the electronic government of domestic convergence with role of the u-Gov due to an evolution with convergence, for it attains the administrative idea which u-Gov pursues. And by convergence analysis of issue, hereafter it presented a policy propulsion direction of convergence.

• Journal of Elementary Mathematics Education in Korea
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• v.22 no.3
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• pp.267-282
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• 2018

The purpose of this study is to develop and apply a Convergence program for teaching of congruence and symmetry and to investigate the effects of the mathematical creativity and convergence talent. For these purposes, research questions were set up as follows: 1. How is a Convergence program for teaching of congruence and symmetry developed? 2. How does a Convergence program affect the mathematics creativity and convergence talent of fifth grade student in elementary school? The subjects in this study were 16 students in fifth-grade class in elementary school located in Songpa-gu, Seoul. A Convergence program was developed using the integrated unit design process chose the concept of congruence and symmetryas its topic. The developed program consisted of a total 12 class activities plan, lesson plans for 5 activities. Mathematics creativity test, a test on affective domain related with convergence talent measurement were carried out before and after the application of the developed program so as to analyze the its effects. In addition, students' satisfaction for the developed program was investigated by a questionnaire. The results of this study were as follows: First, A convergence program should be developed using the integrated unit design process to avoid focusing on the content of any one subject area. The program for teaching of congruence and symmetry should be considered students' learning style and their preferences for media. Second, the convergence program improved the students' mathematical creativity and convergence talent. Among the sub-factors of mathematical creativity, originality was especially improved by this program. Students thought that the program is good for their creativity. Plus, this program use two subject class, Math and Art, so student do not think about one subject but focus on topic 'congruence and symmetry'. It help students to develop their convergence talent.

• Korean Institute of Interior Design Journal
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• v.25 no.6
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• pp.15-22
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• 2016

Recent changes in the Korean education policies are promoting the advances in science and technology and cultivating people of convergence talent. STEAM (science, technology, engineering, art and math) educational program is Korean styled convergence program for creative competent human resources. Therefore, Therefore the aim of this study is developing convergence hand-on educational program coping with climate change for elementary school students. For development of the program, we investigated the curriculum of the elementary school about the climate change, and allocated in the creative learning standard frame. Also, we selected themes related the climate change in the curriculum and learning activity. For more effective program to build the convergence competency, we analyzed the program based on creative problem based learning process and 4 core competency(creativity, communication, convergence, caring) elements. In conclusion, the STEAM program needs to develop by school curriculum and leaner's ability. For elementary school students, the STEAM program consists with creative problem based learning process. And the convergence educational program would analyze by the creative PBL process and convergence competency elements. So, this developing program has brought the promotion of the creative convergence competent talented person for the future global environment.

• Current Optics and Photonics
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• v.1 no.2
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• pp.157-162
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• 2017

In large liquid crystal displays, the image quality in an oblique viewing direction is a crucial issue. From this perspective, 8-domain polymer-stabilized vertical alignment (PS-VA) mode has been developed to suppress the color shift in oblique viewing directions, compared to that in 4-domain PS-VA mode. To realize the 8-domain PS-VA, the four domains in a pixel are each divided into two regions, such that applying different electric potentials result in different tilt angles in these two regions, while keeping four azimuthal directions in each domain. However, applying different voltages in a pixel causes drawbacks, such as requiring additional processes to construct a capacitor and a transistor, which will further reduce the aperture ratio. Here we propose a different approach to form the 8-domain, by controlling surface polar anchoring energy and the width of patterned electrodes in two regions of a pixel. As a result, the gamma-distortion index (GDI), measured at an azimuthal angle of $0^{\circ}$, is reduced by about 23% and 8%, compared to that of a conventional 4-domain at polar angles of $30^{\circ}$ and $60^{\circ}$ respectively.