• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.659-669
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• 2008

Two sets of four parallel activated sludge reactors (ASRs) maintaining an MLSS of 3000 mg/L were operated to investigate the effect of DO, HRTs and bio-contact media (BCM) packing ratios on the removal efficiency of organic matters and nitrogen. Packing ratios of BCM to BCM-ASR systems 1, 2, 3, and 4 were 0% (suspended growth only), 10%, 15% and 20%, respectively. All systems were operated at an HRT of 4 hr, 6 hr, and 8 hr, respectively; DO concentration was maintained 0.5~1.0 mg/L and 1.5~2.0 mg/L for each HRT condition. In terms of TSS, TCODcr and SCODcr removal efficiency, all systems had a similar level of the removal efficiency under varied HRTs, and DO. But organic removal efficiency of systems with BCM was approximately 3~5% higher than systems without BCM at the same HRT and the DO. About the nitrification efficiency, with high DO (1.5~2.0 mg/L), as HRT (4 hr, 6 hr, 8 hr) or BCM packing ratio increased, the slight increment of nitrification efficiency was observed. However, under the low DO (0.5~1.0 mg/L), increase of BCM packing ratio and HRT resulted in large increase of the nitrification efficiency. At the same HRT and BCM packing ratio, the nitrification efficiency increased greatly with up to 15% as DO increased. When the HRT increased from 4hr to 8hr, the denitrification efficiency slightly increased by 5~10% only, under all DO conditions. Systems with BCM had higher denitrification efficiency, ranged 62.7~91.1% than systems without BCM showed 32.1~65.6%. And the increase in BCM packing ratio from 10% to 20% resulted in about 14~16% denitrification efficiency increment. BCM packing ratio showed great effect on the denitrification. The increase of the DO (from 0.5~1.0 mg/L to 1.5~2.0 mg/L) at the same HRT and BCM packing ratio resulted in slight decrease of denitrification efficiency with up to 7% for systems with BCM. But for systems without BCM, the denitrification efficiency decreased with up to 28%. In all system, the denitrification efficiency had more influence on the TN removal efficiency than nitrification efficiency. So, BCM packing ratio (0%, 10%, 15%, 20%) has greater effect on the TN removal than HRT and DO. The TN removal efficiency increased as packing ratio of BCM increased with up to 45%. As a result, the highest TN removal efficiency was observed 73.7% at the condition showed the highest denitrification efficiency that DO of 0.5~1.0 mg/L, an HRT of 8 hr, and 20% of BCM packing ratio was maintained.

• Journal of Food Hygiene and Safety
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• v.33 no.5
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• pp.339-346
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• 2018

This study was conducted to monitor the current status of pesticide residues in a total of 297 agricultural products for raw juice from January 2017 to September 2017. Pesticide residues in samples were analyzed by multiresidue method for the determination of multiclass pesticide with an aim to detect 220 pesticides using GC/ECD, GC/NPD, TOF/MS, LC/PDA, LC/FLD, and LC/MS-MS. The analysis revealed the presence of nine pesticides in 14 samples. The detected pesticides were chlorpyrifos, cyflufenamid, chlorothalonil, pendimethalin, azoxystrobin, pyridalyl, imazalil, fludioxonil and procymidone. The kinds of detected crops were mandarin, carrot, apple, celery, chicory, orange and grape. Risk assessment evaluated human health exposure with the ratio of EDI (Estimated daily intake) to ADI (Acceptable daily intake) of pesticides detected and the range of %ADI (the ratio of EDI to ADI) values was 0.0011~6.7087% and safety level.

• Korean Journal of Plant Taxonomy
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• v.46 no.4
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• pp.405-412
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• 2016

We investigate the intraspecific morphological variations and geographical distributions from twelve populations (28 samples) of Orobanche coerulescens in Korea. Two main morphological types were detected, i.e., glabrous (G-type) and pilose (P-type), in the external morphology (stem, leaf, bract, calyx, and corolla). The G-type was found on Ulleung-do and Dok-do, and the P-type was observed on the coasts of South Korea, Jeju-do and Ulleung-do. The distinct difference in the morphological types and geographical distribution suggested the existence of two putative lineages with different distribution processes. O. coerulescens, distributed in very limited areas, was only identified as the G-type on Dok-do. Hence, conservation efforts should focus on protecting native habitats to conserve native species and the unique biogeographic significance of this species.

• Smart Media Journal
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• v.12 no.2
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• pp.66-75
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• 2023

Recently, the number of cloud web applications is increasing owing to the accelerated migration of enterprises and public sector information systems to the cloud. Traditional network attacks on cloud web applications are characterized by Denial of Service (DoS) attacks, which consume network resources with a large number of packets. However, HTTP DoS attacks, which consume application resources, are also increasing recently; as such, developing security technologies to prevent them is necessary. In particular, since low-bandwidth HTTP DoS attacks do not consume network resources, they are difficult to identify using traditional security solutions that monitor network metrics. In this paper, we propose a new detection model for detecting HTTP DoS attacks on cloud web applications by collecting the application metrics of web servers and learning them using machine learning. We collected 18 types of application metrics from an Apache web server and used five machine learning and two deep learning models to train the collected data. Further, we confirmed the superiority of the application metrics-based machine learning model by collecting and training 6 additional network metrics and comparing their performance with the proposed models. Among HTTP DoS attacks, we injected the RUDY and HULK attacks, which are low- and high-bandwidth attacks, respectively. As a result of detecting these two attacks using the proposed model, we found out that the F1 scores of the application metrics-based machine learning model were about 0.3 and 0.1 higher than that of the network metrics-based model, respectively.

• Journal of the korean veterinary medical association
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• v.13 no.3
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• pp.161-166
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• 1977

A survey on prevalence and the efficiency of the field chemotherapeutical administration on fascioliasis-param-phistomiasis about 524 dairy cattles of 20 heards was carried out in the areas of the northern parts of the Gyeonggi-Do by means of fecal examin

• 한국약용작물학회:학술대회논문집
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• 2007.05a
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• pp.135-136
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• 2007

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.04a
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• pp.298-299
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• 2005

• 한국약용작물학회:학술대회논문집
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• 2008.11a
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• pp.185-186
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• 2008

• 한국약용작물학회:학술대회논문집
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• 2011.04a
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• pp.134-135
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• 2011

• 한국약용작물학회:학술대회논문집
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• 2011.09a
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• pp.270-271
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• 2011