• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.85.2-85.2
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• 2011

A new infrared spectro-polarimeter was installed in 2008 onto the Solar Flare Telescope of NAOJ in the Mitaka headquarters. The Solar Flare Telescope had been operated previously as a filter-based magnetograph and obtained vector magnetograms of active regions with the Fe I 630.3nm line during 1992 - 2005. The aim of this new instrument is to measure the distribution of magnetic helicity over the whole Sun and for an extended period with high magnetic sensitivity in the infrared wavelengths. This spectro-polarimter is able to obtain polarizations in both photospheric and chromospheric layers. In order to take full Stokes profiles, we observe Fe I 1564.8 nm and He I 1083.0 nm lines (with the neighboring photospheric Si line) for the photospheric and chromospheric magnetic field vectors, respectively. The infrared detector of this instrument is a $640{\times}512$-pixel InGaAs camera produced by a Belgian company Xenics. The frame rate of the camera is 90 frames/sec. The 640-pixel row of this camera is set along the spectrograph slit of the polarimeter. Since the slit only covers the solar hemisphere, a full disk map is obtained by raster scanning the solar disk twice. A magnetic map is made of about $1200{\times}1200$ pixels with a pixel size of 1.8 arcsec. It generally takes 1.5 hours to scan the whole Sun. Although some issues on the instrument calibration still remain, a few maps of the whole Sun at the two wavelengths are now taken daily. In this presentation, we will introduce the instrument and present some observational results.

• Preventive Nutrition and Food Science
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• v.19 no.3
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• pp.145-155
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• 2014

Vascular dementia is characterized by white matter lesions involving the demyelination and activation of astrocytes and microglia. In a previous study, we showed that the supernatant of a laboratory-scale, hot water extract of ground whole wheat (TALE) attenuated white matter injury and astrocytic activation in a rat model of bilateral common carotid artery occlusion (BCCAO). In the present study, we made several modifications to the hot water extraction process to remove starch and enable large-scale production. We used wheat bran (WB), which contains less starch, instead of ground whole wheat. In addition, we removed starch granules with a decanter before hot water extraction. The final product, wheat bran extract (WBE), contained 2.42% arabinose, a surrogate marker of arabinoxylan, which is an active constituent of WBE. Supplementation of the rat model of BCCAO with WBE (400 mg/kg/day) for 33 days attenuated white matter injury, which was assessed by Luxol Fast Blue staining, in the corpus callosum (cc) and optic tract (opt) regions. Attenuation of white matter injury in the opt region was accompanied by improvement of the pupillary light reflex. Immunochemical staining revealed that supplementation with WBE reduced astrocytic activation in the cc and opt regions and reduced microglial activation in the opt region. These findings indicate that supplementation with WBE is effective at attenuating white matter injury accompanied by the inhibition of astrocytic and microglial activation. Therefore, extracts from WB, a cheap by-product of wheat milling, can be developed as a nutraceutical to prevent vascular dementia, a disease for which there is no approved pharmaceutical treatment.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.9
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• pp.1429-1441
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• 2010

This study examines the post-national trends of the $21^{st}$ century fashion that has embraced multiculturalism. This study conducted a literature view to explore the concept of multiculturalism and the background of post-national phenomena appearing in contemporary fashion. In addition, as a case study, the author used local and foreign fashion magazines and collections published between 2000 and 2009, in addition to other related materials available on the Internet. The objective was to analyze photographic materials in which post-national features are reflected. From this study, the post-national trends in $21^{st}$ century fashion that adopted multiculturalism are as follows: The first is that oriental culture is more actively embraced. In the past, the tendency of embracing the oriental culture was mainly developed with a focus on China and Japan, but recently the tendency has spread to Southeast Asian countries and national/ethnic minorities that include Mongolians and Tibetans that is present in more active ways that reflect oriental sentiment and philosophy as well as adopts simple images. Second, $21^{st}$ century fashion based on multiculturalism broadens the interest in the understanding of nations in the regions of Africa, Middle East, and South America and uses regional folk costumes or indigenous characteristics to create new things instead of staying within a fixed paradigm. Third, as horizontal transfer is involved in ways of looking at culture, $21^{st}$ century fashion shows a post-national tendency to use regional cultures and folk costumes of the occidental world that includes North and West Europe in addition to non-mainstream regions (as considered so far). Fourth, dress elements of many heterogeneous national cultures are combined to create multinational images difficult to define in terms of a specific national culture or clothing style.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.51-57
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• 2009

Ubiquitous sensor network is the communication environment where sensor nodes move freely and construct network to get the services from the system. So, it does not need fixed infrastructure and can easily be placed in unaccessible regions like war or calamity area. Wireless sensor network protocol has self-organizing capability, need to adapt topology change flexibly and also has technique that sensor nodes work cooperatively, because network disconnection is frequently occurred due to the active mobility of sensor nodes. In this paper, we design a cluster based fault-tolerant routing protocol for the efficient topology construction and to guarantee stable data transmission in USN. The performance of the proposed protocol is evaluated by an analytic model.

• Journal of Astronomy and Space Sciences
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• v.32 no.4
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• pp.427-434
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• 2015

Coronal Mass Ejections (CME), which originate from active regions of the Sun's surface, e.g., sunspots, result in geomagnetic storms on Earth. The variation of the Earth's geomagnetic field during such storms induces surface currents that could cause breakdowns in electricity power grids. Hence, it is essential to both monitor Geomagnetically Induced Currents (GICs) in real time and analyze previous GIC data. In 2012, in order to monitor the variation of GICs, the Korean Space Weather Center (KSWC) installed an induced current measurement system at SINGAPYEONG Substation, which is equipped with 765 kV extra-high-voltage transformers. Furthermore, in 2014, two induced current measurement systems were installed on the 345 kV high-voltage transformers at the MIGEUM and SINPOCHEON substations. This paper reports the installation process of the induced current measurement systems at these three substations. Furthermore, it presents the results of both an analysis performed using GIC data measured at the SINGAPYEONG Substation during periods of geomagnetic storms from July 2013 through April 2015 and the comparison between the obtained GIC data and magnetic field variation (dH/dt) data measured at the Icheon geomagnetic observatory.

• Publications of The Korean Astronomical Society
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• v.13 no.1 s.14
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• pp.39-54
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• 1998

We have developed solar observational system in the department of Astronomy & Space Sciences of KyungHee University, in order to monitor solar activities and construct solar database for space weather forecasting at maximum of 23rd solar cycle, as well as an solar education and exercise for undergraduate students. Our solar observational system consists of the full disk monitoring system and the regional observation system for H a fine structure. Full disk monitoring system is made of an energy rejection filter, 16cm refractor, video CCD camera and monitor. Monitored data are recorded to VHS video tape and analog output of video CCD can be captured as digital images by the computer with video graphic card. Another system for regional observation of the sun is made of energy rejection filter, 21cm Schmidt-Cassegrain reflector, H a filter with 1.6A pass band width and $375\times242$ CCD camera. We can observe H a fine structure in active regions of solar disk and solar limb, by using this system. We have carried out intense solar observations for a test of our system. It is found that Quality of our H a image is as good as that of solar images provided by Space Environmental Center. In this paper, we introduce the basic characteristics of the KyungHee Solar Observation System and result of our solar observations. We hope that our data should be used for space weather forecasting with domestic data of RRL(Radio Research Laboratory) and SOFT(SOlar Flare Telescope).

• Journal of Environmental Science International
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• v.20 no.4
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• pp.551-554
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• 2011

The production of the sharp-toothed eel by commercial catch off waters of Korea is annually declined after 1978. This study was carried out to obtain the stock management of the sharp-toothed eel using the PCR-aided RFLP method. The mtDNA COI gene was amplified using species-specific primers and PCR product was observed to 700 bp. Amplified DNA fragments were treated with six kinds of restriction enzymes (BaeHI, EcoRI, PstI, Ksp22, HinfI and HaeIII). The treatment of HaeIII showed a distinct PCR product between Yeosu/Jinhae/Jeju/Goseoung and Jangheung/Haenam populations that were observed from 300 to 400 bp in reference to 100 bp molecular marker. However, DNA fragment within populations had an identical pattern. The phylogenetic homology is 82% between two populations inferred from RFLP PCR product pattern using NTsysPC ver. 2.1. The use of HaeIII plays an important role in discriminating populations. It is thought that adults after over-wintering in the southern part of Jeju migrate to the Yeosu, Jinhae and Goseoung regions to spawn instead of to southwestern waters. Individuals within populations showed a relatively active genetic mixing and migration regardless of geography. However, the genetic ancestor of Jangheung and Haenam populations is appeared to be more adjacent to China or Japan than Jeju.

• Structural Engineering and Mechanics
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• v.78 no.2
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• pp.209-218
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• 2021

For engineering, there are two major challenges in reliability analysis. First, to ensure the accuracy of simulation results, mechanical products are usually defined implicitly by complex numerical models that require time-consuming. Second, the mechanical products are fortunately designed with a large safety margin, which leads to a low failure probability. This paper proposes an efficient and high-precision adaptive active learning algorithm based on the Kriging surrogate model to deal with the problems with low failure probability and time-consuming numerical models. In order to solve the problem with multiple failure regions, the adaptive kernel-density estimation is introduced and improved. Meanwhile, a new criterion for selecting points based on the current Kriging model is proposed to improve the computational efficiency. The criterion for choosing the best sampling points considers not only the probability of misjudging the sign of the response value at a point by the Kriging model but also the distribution information at that point. In order to prevent the distance between the selected training points from too close, the correlation between training points is limited to avoid information redundancy and improve the computation efficiency of the algorithm. Finally, the efficiency and accuracy of the proposed method are verified compared with other algorithms through two academic examples and one engineering application.

• Korean Journal of Medicinal Crop Science
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• v.28 no.5
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• pp.360-370
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• 2020

Background: Sophora flavescens AIT root is used as a herbal medicine in Asian culture. This study was aimed at selecting the best cultivars, by comparing growth characteristics, active ingredients, and antioxidant activities. Methods and Results: A total twenty nine accessions of S. flavescens were collected from five different regions in Korea. Plant height, leaf length, peduncle length, fresh root weight, and seed weight were the growth characteristics selected. Antioxidant activity was determined by measuring the total polyphenol (TPC) and total flavonoid contents (TFC) as well as the radical scavenging activity of DPPH, ABTS and FRAP. Oxymatrine and matrine, active ingredients in S. flavescens were analyzed by HPLC. Results indicated that accession YS-11 had the highest plant height (152.5 cm) and peduncle length (54.0 cm). The fresh root weight was highest in JA-01 at 4.9 kg, while the highest total seed weight was recorded in accession BH-04 at 77.7 g. The YS-03 accession contained the highest oxymatrine and matrine total contents (0.9616% and 0.9638%, respectively). Accessions BH-02, YS-11, YS-05, and MJ-03 had the highest levels of antioxidant activity (p < 0.05). Oxymatrine showed a high correlation with TPC and FRAP. TPC showed high correlations with TFC, DPPH, ABTS and FRAP. TFC showed a high correlation with DPPH. Conclusions: The superior lines can be selected for use as standard variety breeding material by comparing the growth characteristics of the accessions.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.63.2-63.2
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• 2013

We have investigated the EUV coronal jets observed by Solar Dynamic Observatory (SDO) / Atmospheric Imaging Assembly (AIA). From the Heliophysics Events Knowledgebase (HEK), we consider all recorded 40 EUV jets in $171{\AA}$ from May 2010 to July 2011 and use 19 jets whose location can be clearly identified, excluding limb events because of the ambiguity of their positions. According to the positions of their roots, these coronal jets are classified into two types: bright point jet (BPJ, 9 jets) and active region boundary jet (ABJ, 10 jets). BPJs are located at the top of bright points and ABJs at the boundaries of active regions. There are significant differences in speed and size between two types. Here the speed and size of a jet are assumed to be its maximum values in the case that the jet has several ejections. The average speed and size of 9 BPJs are about 110 km/s and 69,000km, respectively. The average speed and size of 10 ABJs are about 660 km/s and 194,000 km, respectively. The speed distribution of ABJs has two peaks at about 270 km/s and 1700 km/s. It is very interesting to note that three ABJs have very high speeds larger than 1600 km/s and they are all composed of a group of recurrent jets with low and high speed at the same location. In addition, we are investigating these events in other wavelengths and compare their characteristics.