• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.7
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• pp.1007-1013
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• 2012

Modeling of photovoltaic power systems is significant to analytically predict its dynamics in practical applications. This paper presents a novel modeling algorithm of such system by using probability and statistic theories. We first establish a linear model basically composed of Fourier parameter sets for mapping the input/output variable of photovoltaic systems. The proposed model includes solar irradiation and ambient temperature of photovoltaic modules as an input vector and the inverter power output is estimated sequentially. We deal with these measurements as random variables and derive a parameter learning algorithm of the model in terms of statistics. Our learning algorithm requires computation of an expectation and joint expectation against solar irradiation and ambient temperature, which are analytically solved from the integral calculus. For testing the proposed modeling algorithm, we utilize realistic measurement data sets obtained from the Seokwang Solar power plant in Youngcheon, Korea. We demonstrate reliability and superiority of the proposed photovoltaic system model by observing error signals between a practical system output and its estimation.

• Cross-Cultural Studies
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• v.19
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• pp.313-338
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• 2010

Attitudes toward target language culture and motivation have been known as important factors in second or foreign language learning. In this study, cadets' attitudes toward the target language community and culture were investigated to find out any relationships with English achievement. Integrative or instrumental motivation in foreign military context was investigated to determine which motivation was more positively related to English proficiency. Cadets' responses were shown highly positive and internally consistent in most cases. Military cadets' attitudes toward American culture were statistically significant and could predict their English achievement. Even though integrative motivation was statistically significant, correlation with English achievement was low. However, instrumental motivation was not significant. This result implies that attitudes toward culture is an important factor in foreign language learning and integrative-instrumental motivation dichotomy might not be enough to explain specific context like cadets' English learning situation at Korea Army Academy at Youngcheon.

• Current Research on Agriculture and Life Sciences
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• v.14
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• pp.15-28
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• 1996

The effective components of the peony cultivar, Euseongjagyag and Youngcheonjagyag, which were the major cultivars of peony in Kyeongbuk area, were determined with HPLC and TLC. The paeoniflorin content in the root of Euseongjagyag were more than that of Youngcheonjagyag. The root of Euseongjagyag contained much albiflorin and Youngcheonjagyag contained much oxypaeoniflorin in comparision with albiflorin and oxypaeoniflorin contents in both cultivars of peony. Paeoniflorin contents in accordance with peony prodution regions were ranged from 2.15% to 4.08%, and paeoniflorin content of local cultivar of Euseong and that of Geochang were approximatly the same but that of Youngcheon was the lowest. Paeoniflorin content in the 18 accessions of peony cultivar which were collected from Kyeongbuk area and harvested on November 1993, were ranged from 1.41% to 5.30%. The 18 accessions of peony were classified with the HPLC chromatogram pattern of peony root extract into the three groups which composed with Euseong peony group(9 accessions), Youngcheon peony group (4 accessions) and Punggi standard peony group(5 accessions). High content of paeoniflorin WaS contained in peony root harvested in May and November. but low content of paeoniflorin was contained in peony root harvested in March and September.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.347-355
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• 2009

Grape fruit quality can be deteriorated with leaf chlorosis caused by magnesium (Mg) deficiency during fruit coloring season in several grapevine varieties. The occurrence of leaf chlorosis and soil Mg states for four grapevine varieties (Campbell Early, Muscat bailey A (MBA), Sheridan, and Kyoho) in the vineyards of Gyeongsan and Youngcheon were surveyed. The relationships between leaf chlorosis and fruit qualities were also investigated. Leaf chlorosis was more widely found and the symptom was stronger in Campbell Early in comparison to the other varieties. Sugar content and Hunter values (L, a, b) of grape fruit were significantly lower in the trees of chlorosis when compare to healthy grapevine trees. Soil Mg contents in the vineyards where leaf chlorosis was found were lower than the optimum level for grapevine. Also Mg content in the petioles of chlorosis grapevines was significantly lower than healthy grapevines. Application of Mg through foliar spray and soil fertigation was quite effective in correcting deficiencies of Mg in grapevine. Proper management of soil Mg availability and K/Mg ratio is strongly recommended to prevent Mg deficiency in grapevine.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.33.1-33.1
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• 2008

As a part of the construction of Korean Space Weather Prediction Center (K-SWPC), Korea Astronomy and Space Science Institute (KASI) installed a Scintillation Monitor (SCINTMON) and an All-Sky Camera to observe upper atmospheric/ionospheric phenomena. The SCINTMON is installed in KASI building in Daejeon in cooperation with Cornell university and is monitoring the ionospheric scintillations on GPS L-band signals. All-Sky Camera is installed at Mt. Bohyun in Youngcheon in cooperation with Korea Polar Research Institute. It is used to take the photograph for upper atmospheric layer through appropriate filters with specific airglow or auroral emission wavelengths and to observe upper atmospheric disturbance, propagation of gravity wave and aurora. The integrated data from the instruments including SCINTMON and All-Sky Camera will be used for giving nowcast on the space weather and making confidential forecast based on some space weather prediction models.

• Archives of Craniofacial Surgery
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• v.19 no.1
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• pp.1-2
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• 2018

Theoretically, panfacial bone fractures involve all three areas of the face: frontal bone, midface, and mandible. In practice, when two out of these three areas are involved, the term "panfacial bone fracture" has been applied. We can use physical examination, simple radiologic examination, and computed tomography study for diagnosis. Linear fracture are treated by conservative treatment. But, most of panfacial bone fracture patients need to be treated by open reduction and internal fixation. Facial width is most important thing that we need to care during operation. There are many ways about sequence like "top to bottom," "bottom to top," "outside to inside," or "inside to outside" and the authors prefer "top to bottom" and "outside to inside" ways. The authors apply arch bar from the first of surgery and then, set frontal bone fracture, midface fracture and mandible fracture in sequence. Usually, we remove the stitches for 5 days after surgery and the intraoral stitch removed after 2 weeks. Usually arch bar is going to be removed 4 weeks after surgery. We could get acceptable results with the above way.

• Korean Journal of Hydrosciences
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• v.8
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• pp.31-40
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• 1997

Flow carrying capacity of water distribution systems is getting reduced by deterioration of pipes in the systems. The objective of this paper is to present a managerial decision-making model for the rehabilitation of water distribution systems with a mininum cost. The decisions made by the model also satisfy the requirements for discharge and pressure at demanding nodes in the systems. Replacement cost, pipe break repair cost, and pumping cost are considered in the economic evaluation of the decision along with the break rate and the interest rate to determine the optimal replacement time for each pipe. Then, the hydraulic integrity of the water distribution system is checked for the decision by a pipe network simulator, KYPIPE, if discharge and pressure requirements are satisfied. In case the system does not satisfy the hydraulic requirements, the decision made for the optimal replacement time is revised until the requirments are satisfied. The model is well applied to an existing water distribution system, the Seoul Metropolitan Water Supply System (1st Phase). The results show that the decisions for the replacement time determined by the economic analysis are accepted as optimal and hydraulic integrity of the system is in good condition.

• Journal of Korea Water Resources Association
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• v.37 no.2
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• pp.121-131
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• 2004

SIMHYD and TANK model are used to predict time series of daily rainfall-runoff of Soyang Dam and Youngcheon Dam watershed. The performances of SIMHYD model with 7 parameters and TANK model with17 parameters are compared. Three optimization methods (Genetic algorithm, Pattern search multi-start and Shuffled Complex Evolution algorithm) were applied to study-areas with 3 different types of objective functions. Efficiency of TANK model is higher than that of SIMHYD. Among different types of objective function, Nash-sutcliffe coefficient is found to be the most appropriateobjective function to evaluate applicability of model.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.269-270
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• 2015

We carried out near-IR photometric and optical spectroscopic observations of V582 Aur, which is a FU Orionis type object, to investigate any periodic and/or aperiodic variations. We obtained light curves on the scale of a night and a year, in J, H and Ks bands with KASINICS (KASI Near Infrared Camera System) attached to the BOAO (Bohyun-san Optical Astronomy Observatory) 1.8-m reflector in Youngcheon, South Korea and examined photometric variations on the two time scales. So far we have not found any periodic brightness variations on the scale of a night. On the other hand, we have found that there seems to be a periodic brightness variation with a period of approximately 45 days. In addition, high-resolution optical spectroscopic observations of V582 Aur were performed from February 2013 to May 2014 with the high-resolution echelle spectrograph BOES attached to the BOAO 1.8-m reflector. We analyzed several spectral lines to understand the physical state of V582 Aur. The P Cyg profiles are clearly shown in the $H{\alpha}$ line and Na I D line.

• IMMUNE NETWORK
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• v.23 no.2
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• pp.13.1-13.24
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• 2023

The coronavirus disease 2019 (COVID-19) pandemic is one of the most consequential global health crises in over a century. Since its discovery in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to mutate into different variants and sublineages, rendering previously potent treatments and vaccines ineffective. With significant strides in clinical and pharmaceutical research, different therapeutic strategies continue to be developed. The currently available treatments can be broadly classified based on their potential targets and molecular mechanisms. Antiviral agents function by disrupting different stages of SARS-CoV-2 infection, while immune-based treatments mainly act on the human inflammatory response responsible for disease severity. In this review, we discuss some of the current treatments for COVID-19, their mode of actions, and their efficacy against variants of concern. This review highlights the need to constantly evaluate COVID-19 treatment strategies to protect high risk populations and fill in the gaps left by vaccination.