• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.49.1-49.1
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• 2011

Utilizing single-epoch spectra and the empirical relation between the size of the broad-line region and AGN continuum luminosity, the so-called single-epoch method has been widely used for estimating AGN black hole masses. However, the systematic uncertainties and the potential biases of this method are not well examined. Taking the full advantage of the high-quality homogeneous spectra from the Lick AGN Monitoring Project (LAMP), we investigate in detail the uncertainties of single-epoch mass estimates by comparing with the reverberation-mapping results. We find that the uncertainty due to AGN variability is less than 0.1 dex, while there is a systematic offset between single-epoch masses and reverberation masses. Particularly, narrow-line Seyfert 1 galaxies show that the Hbeta line widths measured from single-epoch (or mean) spectra are systematically larger than those from rms spectra, indicating a potential bias of single-epoch masses. We will present the detailed measurement method, the test of virial assumption, and the systematic uncertainties.

• The Plant Pathology Journal
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• v.33 no.2
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• pp.109-117
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• 2017

Tan spot caused by the fungus Pyrenophora triticir-repentis is a serious disease of wheat, which is on increase in recent years in Mediterranean region. In the field this fungus produces a diamond-shaped necrotic lesions with a yellow halo on wheat foliage. The objective of this study was to characterize and compare several monospore isolates of P. tritici-repentis collected from different infected wheat fields in various locations of Algeria, and find the morphological differences between them, if any. The results revealed wide morphologically variation among the isolates based on colony colors and texture, mycelial radial growth and conidial size.

• Tribology and Lubricants
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• v.16 no.3
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• pp.208-217
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• 2000

Turbulence in journal bearing operation is examined and the thermal variability is studied for isothermal, convective and adiabatic conditions on the walls within some degree of journal misalignment. An efficient algorithm for the solution of the coupled turbulent Reynolds and energy equations is used to examine the effects of the various factors. The calculation data of turbulent analysis are compared with those of laminar analysis. Heat convection is found to play but a small role in determining friction and load. The friction distribution patterns through the journal bearing are now different with high values at the upstream region of the bearing due to the high speed and low temperature, and a sudden decrease past the pressure maximum.

• KSTLE International Journal
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• v.1 no.2
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• pp.76-82
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• 2000

Turbulence in journal bearing operation is examined and the thermal variability is studied for isothermal, convective and adiabatic conditions on the walls under aligned and misaligned conditions. Also, the effects of a contraction ratio at the cavitation region and the mixing between re-circulating oil and inlet oil on the fluid field of oil film are included. An algorithm for the solution of the coupled turbulent Reynolds and energy equations is used to examine the effects of the various factors. Heat convection is found to play only a small role in determining friction and load under no mixing condition. However, under realistic mixing condition, the heat convection cannot be ignored. The wall temperature and heat transfer have been found to be of secondary important factors to the mixing effectiveness at the groove and the final mixture temperature.

• Ocean and Polar Research
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• v.25 no.4
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• pp.645-652
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• 2003

The coastal environment of King George Island is potentially subject to contamination by pollutants arising from station operations, such as emissions from fossil fuel burning, oil spills, waste disposal, etc. As a preparatory step to assess such impacts on the marine environment and living organisms of this island, two molluscan species (the bivalve Laternula elliptica and the gastropod Nacella concinna) were selected as biomonitors for metal pollution monitoring, and their baseline levels have been investigated for the past several years at King Sejong Station. In this review, variability of the baseline levels is discussed in relation to body size, tissue type, and sex. Natural elevations of some metals are also discussed with respect to the environmental characteristics of this region.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2001.06a
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• pp.39-42
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• 2001

There is general agreement that the mean land-surface air temperature of the Earth has increased by about 0.6 over the past century (Vinnikov et al., 1990; Jones, 1994). However, IPCC concluded in 1996 that the observed warming was "broadly consistent with predictions of climate models, but it was also the same magnitude as natural climate variability".(omitted).(omitted)

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.2
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• pp.65-69
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• 2013

In situ measurement of a primary production in East Sea, a marginal sea with a fair accessibility, is nonetheless an arduous task because of dynamic variability. In this study, we estimated the mean value of background (gross) primary production over the warm region of the East Sea based on a biogeochemical hypothesis. We propose an immiscible-shoaling hypothesis for the estimation of primary production, which assumes that primary production in the warm region occurred only by the nutrient supply through the Korea Strait. Annual primary production thus estimated is $209\;gC\;m^{-2}\;y^{-1}$, which is comparable to the satellite-based estimates of net primary production in the region. However, since this hypothesis assumes that primary production is based on only the new nutrients supplied to the system, primary production would increase by 40% if we release the assumption, and assume f = 0.6. This suggests that nutrient influx through the Korea Strait alone is more than enough to support primary production previously reported. Primary production may increase as much as two times if we considered other external perturbations excluded intentionally to estimate the background level of primary production, such as coastal upwelling, submerged ground water discharge, aeolian input, ocean dumping, and mixing by typhoons as well as the contribution of cyanobacteria that has not been quantified in the region. This implies the primary production in the warm region of the East Sea would be comparable to that of the Peru upwelling region with f = 0.6.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.5
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• pp.653-660
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• 2007

In this study, we have investigated sequence variants in the PRNP gene of 20 individuals belonging to the Korean cattle, and have analyzed and compared genetic features between varieties of other cattle breeds. Of the 73 sequence variants identified in Korean cattle, 27 were identified for the first time in this study, whereas 46 of these polymorphisms had previously been isolated. We discovered a 2.6 kb SNP hot spot region localized on the putative promoter region of the PRNP gene. Furthermore, the copy numbers of the octapeptide repeat (24 bp indel) which is detected on the coding sequence (CDS) of the PRNP exhibited a completely homozygous 6/6 genotype which is dominant in other cattle breeds. We also characterized a new 19 bp/10 bp allele located on the putative promoter region of the PRNP gene, which represented 0.71 in allele frequency. To the best of our knowledge, this report is the first to address polymorphisms of the PRNP gene structure in Korean cattle in which BSE has yet to be discovered. Therefore, our findings may prove useful with regard to our current understanding of allelic diversity in bovine species, and may also provide new insights into the genetic factors associated with susceptibility or resistance to BSE.

• Journal of the Korean Institute of Rural Architecture
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• v.14 no.1
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• pp.83-90
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• 2012

The purpose of this study was to set and analyze the standard model for prioritizing and deciding to take part in housing environment improvement project in the perspective of the public sector. The results of this study were as follows. The location competitiveness, potential demand, marketability and competitive price, etc were selected by assessment indicators. And Various indicators, including of the size of the area, public transportation, accessibility, convenience of living and the influx of the population, were used by weights indexes. The profit of local residents and the public promoter, variability of earnings, sensitivity analysis and the ratio of money in reserve, etc were also established as detailed indexes for the profitability and business risk analysis. To analyze the cash flow of the project process and review the necessary capital in advance, the payback, total working expenses, gearing ratio and sensitivity of a risk, etc were also set as additional detailed indexes. Lastly, considering it is quasi-public projects, the measure to protect tenants, necessity need of redevelopment and local government's will were additionally used by indexes. And Points were distributed on the importance of each index and scored out of 100. It will allow for the public project promoter to decide rationally whether to come in on the project. The public project promoter like the Korea Land and Housing Corporation will be able to make use of various indexes are based on this study to make decision whether joining the housing environment improvement project in depressed region.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.507-519
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• 2023

Multi-temporal optical images have been utilized for time-series monitoring of croplands. However, the presence of clouds imposes limitations on image availability, often requiring a cloud removal procedure. This study assesses the applicability of various machine learning algorithms for effective cloud removal in optical imagery. We conducted comparative experiments by focusing on two key variables that significantly influence the predictive performance of machine learning algorithms: (1) land-cover types of training data and (2) temporal variability of land-cover types. Three machine learning algorithms, including Gaussian process regression (GPR), support vector machine (SVM), and random forest (RF), were employed for the experiments using simulated cloudy images in paddy fields of Gunsan. GPR and SVM exhibited superior prediction accuracy when the training data had the same land-cover types as the cloud region, and GPR showed the best stability with respect to sampling fluctuations. In addition, RF was the least affected by the land-cover types and temporal variations of training data. These results indicate that GPR is recommended when the land-cover type and spectral characteristics of the training data are the same as those of the cloud region. On the other hand, RF should be applied when it is difficult to obtain training data with the same land-cover types as the cloud region. Therefore, the land-cover types in cloud areas should be taken into account for extracting informative training data along with selecting the optimal machine learning algorithm.