• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.67.2-67.2
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• 2010

We present results of searching for the Very Low Luminosity Objects (VeLLOs; internal luminosity : $L_{int}$ < $0.1(d/140pc)^2\;L\odot$) in the Gould's Belt clouds using observations from 3.6 to 70 micron by the Spitzer Space Telescope. The clouds are California, Chamaeleon I, III, Musca, Lupus V, VI, Scorpius, Serpens, Corona Australis, Cepheus, and IC 5146 having the properties of active low-mass star-forming such as the Taurus cloud. The observing sensitivity of the Spitzer data is estimated to be about $L_{int}\;\geq\;5\times10^{-3}(d/140pc)^2\;L\odot$, a factor of 20 better than that of the Infrared Astronomical Satellite (IRAS). The observing data were processed by the c2d Legacy pipeline. As the criteria to select the VeLLOs, we slightly modified previous ones by Dunham et al. The most important criterion is a flux density at 70 micron that is directly converted to the internal luminosity. Also, we used additional criteria to remove the contamination of evolved stars and extragalaxies which have colors or SEDs very similar to YSOs. We identified a total of 64 new embedded VeLLO candidates with $L_{int}$ < $0.1(d/140pc)^2\;L\odot$, consisting of 8 in California, 15 in Chamaeleon-Musca, 13 in Scorpius-Lupus, 20 in Serpens, 3 in Corona Australis, 3 in Cepheus, and 2 in IC 5146. The classification of the spectral index (${\alpha}$) fitted to the shape of the Ks-24 micron SEDs shows most of VeLLO candidates (89%) are in types of Class I and Flat spectrum. We plot various diagrams based on their 2MASS-Spitzer bands colors and magnitudes to discuss properties of the VeLLOs. This search will lead us new adventure toward a future systematic study of the VeLLOs.

• Convergence Security Journal
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• v.20 no.3
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• pp.99-108
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• 2020

The COVID-19 pandemic have been spreading continuously across the world, hence it is difficult to expect coming to an end in a short period of time. The use of digital technology has shown tangible results in suppressing COVID-19, but raised privacy and data-protection concerns. In the context of the global efforts to deal with the coronavirus pandemic, various digital technologies are taking on a role in surveillance, monitoring, and forecasting. Also the Korea government manages Corona crisis based on legal basis. In this paper, Korea and each country's response to the Corona 19 pandemic are shown, and suggests ways to protect personal information while using digital tools. Large-scale data collection and processing is essential for the suppression of pandemic, but it should be limited to the level and scope required privacy. Also international cooperation, temporary and transparent use of personal information, the corresponding legal basis are necessary. As the use of data and algorithms is expected to continue to increase, technical and institutional efforts to reinforce privacy protection must continue.

• Korean Journal of Optics and Photonics
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• v.10 no.3
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• pp.188-194
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• 1999

We synthesized the nonlinear optical (NLO) PI-SOT(polyimide system, 4-[N,N-bis(hydroxyethyl)amino-4,-($\beta$-cyano-$\beta$-methylsulfonyl)vinyl]azobenzene) polymer with high electro-optic coefficients as well as good thermal and temporal stabilities of the elector-optic coefficient ${\gamma}_33$ by the simple Mitsunobu reaction. By using the simple reflection method of C. C. Teng, we measured the thermal and temporal stabilities of the electro-optic coefficient ${\gamma}_33$ of corona-poled PI-SOT polymer at the wavelength of 632.8 nm and 852 nm, respectively. At the temperature of $20^{\circ}C$, the electro-optic coefficient ${\gamma}_33$ of corona-poled PI-SOT polymer were 25.12 pm/V at the wavelength of 632.8 nm and 5.40 pm/V at the wavelength of 852 nm. These values were highly stabilized for more than 60 days at 2$0^{\circ}C$ and stabilized within 6% for more than 10 hours at $100^{\circ}C$.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.7 no.1
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• pp.21-29
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• 1993

In this paper, we studied the 50% flashover voltage of lightening impulse which affect the most serious damages on the insulation of the electric power network system. Also its V -t characteristics and corona process phenomena of pure $SF_6, N_2, SF_6-N_2$mixtures under the circumstances of nonuniform field gap are researched. Comparing the characteristics of pure $SF_6$ with that of $SF_6, N_2$mixtures, we discussed that breakdown processes and $SF_6, N_2$ mixture's application to economics.As a results, 50% flashover voltage of $SF_6$ 50% - $N_2$ 50% for impulse voltage is higher then that of 80% of pure SF6, measured data and calculated data by equal area law are almost equal from the points of view of V-t characteristics. Therefore, it has been known that $SF_6$ 50% - $N_2$ 50% mixtures can be used as an economic constitution gas of pure $SF_6$, it is verified that corona processes from Lichtenberg figure.

• Journal of Digital Convergence
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• v.19 no.10
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• pp.163-173
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• 2021

The purpose of this study was to explore a support model for domestic ICT companies to advance into overseas markets suitable for the post-corona era along with the rapidly changing global economic situation. As a result of the analysis, first, by analyzing the internationalization cases of domestic ICT companies through the realization theory, in the COVID-19 situation, domestic ICT companies organically respond to crisis situations through ad hoc responses, use of international networks, use of external organizations, and resource-based practices. Through qualitative analysis, we were able to confirm that we are growing overseas while achieving our goals. In addition, strategies for domestic ICT companies to grow through internationalization were derived. Ultimately, it was interpreted as a part that required advancement of government policy according to the government's overseas expansion support system.

• Particle and aerosol research
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• v.14 no.4
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• pp.121-133
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• 2018

In this study, we developed a flat-plate type wet electrostatic precipitator that generates stable corona discharge compared to wire type discharge electrode. In order to compare the particle removal efficiency according to the shape of the discharge electrode such as the variation of the horizontal and vertical distance between spiked edges, and the variation of the height of discharge pin support were tested. As a result, when the horizontal distance between spiked edges was increased up to 36 mm, the vertical distance between spiked edges was increased up to 54 mm, and the height of the discharge pin support was increased up to 76 mm, the removal efficiency of PM10 was maintained at approximate 60.0%. Furthermore, the removal efficiency of particles over $5{\mu}m$ was about 80% or more. When the flow rate was 4 m/s, the gap between collection plates was 60 mm, and -14 kV was applied to the discharge electrode. The particle removal efficiency of the flat-plate type electrostatic precipitator was maintained when the horizontal and vertical distance between spiked edges, and the height of the discharge pin support was below a certain level. Those variables may be the important design factors for the shape of the discharge electrode. Therefore, when designing the electrostatic precipitator with multiple channels, the horizontal and vertical distance between spiked edges, and the height of discharge pin support must be selected in consideration of the weight of the discharge electrode and the processing cost.

• Journal of the Korea Convergence Society
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• v.11 no.12
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• pp.309-317
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• 2020

In the post-corona era, telemedicine is becoming more important. This is the case in which it is written, in terms of this study, and in relation to the relationship between the Koreans and the Korean government. In addition, the aim is to prepare effective measures and seek policy suggestions for expanding the introduction of domestic telemedicine in the future. Although Japan has insisted on the necessity of introducing telemedicine in the medical community, it has institutionalized it with a cautious attitude until the establishment of telemedicine. On the other hand, South Korea lacks clear provisions on medical fees for telemedicine and legal measures regarding the responsibility for medical malpractice. Therefore, a clear legal interpretation of the telemedicine subject is needed, and a strategic approach is prioritized, including guidelines and measures for the legal responsibilities and limitations of physicians and patients.

• Journal of Life Science
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• v.31 no.6
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• pp.581-586
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• 2021

The high fatality of COVID-19 (Corona Virus Disease 2019) is closely related to acute pneumonia and severe blood clot formation in brain, heart, kidney and lung. The use of low-molecular weight heparins has been shown to reduce the risk of thrombosis and reduce fatality rates among COVID-19 patients. In this study, we investigated the antithrombotic activity of different parts of C. sativa extracts to determine its potential in preventing blood clots in patients with thromboprophylaxis. The extracts of leaf, stem, root, immature flower and seed of C. sativa showed strong inhibitory activities on blood clot formation. In particular, the flower extract showed the strongest inhibitions against blood coagulation factors and thrombin. Strong hemolysis activities were observed in flower extract and seed extract, suggested that removal of the hemolysis active compounds in th extracts is necessary. This is a first report of anti-thrombosis activities of different parts of C. sativa extracts, and our results suggest that C. sativa extract has potential has a valuable bioresource for high-value products.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.317-325
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• 2021

By analyzing the recognition analysis and motivation method of the determinants, this study investigates the future development direction of health exercise biodata analysis face-to-face practice education content. The participants were 40 millennial and zoomers (MZ) generation college graduates. Factors related to the decision to participate in face-to-face practice classes in the field of health exercise biodata and bio-digital content convergence technology in the era of COVID-19 were measured. Of the participants, 67.5% voluntarily decided to participate in small group classes while observing social distancing rules. This study presented the most effective and learning motive methods to participate in face-to-face training. Health exercise biodata needs improvement in terms of integrating with adjacent disciplines such as big data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.3
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• pp.463-468
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• 2022

COVID-19 is a complex disaster, not an infectious disease-level disaster, and it is difficult to respond with the existing disaster response management method. As a result, experiencing psychological stress and trauma such as 'Corona Blue' has emerged as a new social problem. This study examined the changes in non-face-to-face counseling services using ICT technology and the application cases of image, AI, and VR by companies as the transition to the digital economy accelerates. Based on this, disaster psychological recovery support services were considered to improve the psychological recovery and quality of life of the people after a disaster by establishing a more efficient counseling system and developing counseling services using ICT technology.