• Mycobiology
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• v.42 no.2
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• pp.181-184
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• 2014

To the best of our knowledge, this is the first report on thermophilic fungi isolated in Korea. Three species of thermophiles were isolated from compost and were identified as Myriococcum thermophilum, Thermoascus aurantiacus, and Thermomyces lanuginosus. They can grow at temperatures above $50^{\circ}C$ and produce high levels of cellulolytic and xylanolytic enzymes at high temperatures. Notably, the considerable thermostability of the endo-glucanase produced by T. aurantiacus has made the fungus an attractive source of industrial enzymes.

• Journal of Environmental Science International
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• v.15 no.5
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• pp.461-469
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• 2006

As a frontier of Sustainable Basin Research Initiative, we commenced a scenario-driven planning and evaluation research project which is to identify the strategic policy scenarios. As a part of the project, this study attempts to estimate the ecological impacts of land cover changes using landscape indices at the whole basin level. We analyzed spatio-temporal characteristics of natural area including forest, agricultural land, water area, barren which play an important role in nature-friendly sustainable watershed management. The results of analysis shelved that the size and diversity of natural area have been reduced, while patch number and isolation have been increased in proportion to urbanization in 1974, 1995 and four future scenarios in the Ara River Basin. Also, we estimated that the natural area could be conserved to some degree in the SD or DE scenarios with a concept of environment-friendly development and lifestyle. Various strategic environment policies may be evaluated and designed on the basis of the method, that is, scenario approach and landscape ecological analysis suggested in this study.

• Korean journal of applied entomology
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• v.34 no.4
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• pp.368-372
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• 1995

To develop a microbial pesticide for the control of pine gall midges. Thecodiplosis japonensis, entomopathogenc fungi were isolated from 233 soil samples in the damaged region of Thecodiplosis japonenesis, and identified with Beauveria spp. 29 strains and Paecilomyces spp. 2 strains. The morphology of entomopathogenic fungi was observed by scanning electron miroscope. In addition, the toxicity of entomopathogenic fungi was observed by scanning electron microscope. In addition, the toxicity of entomopathogenic fungi isolated from soil samples was determined by bioassay against Thecodiplosis japonensis larvae. The result showed that toxicity of relatively pathogenic strains, Beauveria spp. SFB-168-2 was 82.9%, suggesting that Beauveria spp. SFB-168-2 is effective entomopathogenic fungi for the control of pine gall midges.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.257-263
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• 2006

This paper examines the physico-chemical properties and structural features of thio lignin and alcohol lignin preparations extracted from fast-growing poplar wood. The lignin preparations were characterized using UV, IR and alkaline nitrobenzene oxidation methods. The yield was higher in thiolignin due to its preparation from wood under drastic alkaline conditions and almost the total amount of alkaline degraded lignin was precipitated except acid soluble lignin. In case of ethanol lignin, structural modifications were comparatively less and form a cream colored lignin more or less similar to its original natural color. The methoxyl values were higher due to syringyl unit present in hard wood lignin in addition to guaicyl unit present in soft wood. The higher values of methoxyl content of isolated lignin revealed that it was built up of high syringyl units. The elementary analysis, methoxyl group and hydroxyl groups were presented by $C_{9}$ formula indicated that it was made up of phenyl propane monomers. Nitrobenzene oxidation of thio lignin and ethanol lignin yield more or less the chromatograms of similar pattern, except difference in relative percentage. The ultra violet spectra of lignins were quite similar, irrespective of the source and method of isolation. Infrared spectroscopy studies of poplar deltoides, thio and ethanol lignin shown different absorption bands which have been utilized for structural investigations.

• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.296-302
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• 1991

Glucose isomerase producer, which produces 488 U/ml of glucose isomerase activity in 500 ml flask scale, was isolated among 666 isolates of Actinomycetes from pine forest soil samples. The isolate was identified as Streptomyces luteogriseus through the studies about morphology (spiral aerial mycelia), cell wall type (Type I), spore chains (spiral form), pigment formation (gray melanine pigment) & metabolism (sugar utilization etc). The optimum conditions of fermentation were determined in 500 ml flask scale. The enzyme production was reached maximum after 4 days at pH 6.0~8.0 and 27~$30^{\circ}C$ in the medium containing 1.5~3.0% of xylose; 0.5-0.8% of glucose; 0.1% of $MgSO_4.7H_20$; 0.05% of $CoCI_2-6H_20$; 7.5% of corn steep liquor.

• Natural Product Sciences
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• v.24 no.4
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• pp.259-265
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• 2018

The three flavone glycosides, 4'-O-methylisoscutellarein 7-O-(6'''-O-acetyl)-${\beta}$-D-allopyranosyl(1${\rightarrow}$2)-${\beta}$-D-glucopyranoside (1), isoscutellarein 7-O-(6'''-O-acetyl)-${\beta}$-D-allopyranosyl(1${\rightarrow}$2)-${\beta}$-D-glucopyranoside (3), and isoscutellarein 7-O-${\beta}$-D-allopyranosyl(1${\rightarrow}$2)-${\beta}$-D-glucopyranoside (4) in addition to a flavonol glycoside, kaempferol 3-O-${\beta}$-D-glucopyranoside (astragalin, 2), were isolated from Stachys japonica (Lamiaceae). In cholinesterase inhibition assay, compound 1 significantly inhibited aceylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities ($IC_{50}s$, $39.94{\mu}g/ml$ for AChE and $86.98{\mu}g/ml$ for BChE). The content of isolated compounds were evaluated in this plant extract by HPLC analysis. Our experimental results suggest that the flavonoid glycosides of S. japonica could prevent the memory impairment of Alzheimer's disease.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.675-682
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• 2021

The study analyzes the demand for residential space in the Untact Era. Residential space comprises six categories: the most necessary dedicated space (DS), most preferred south-facing space (SFS), largest space (LS), most necessary shared space (SS), most necessary infra-space (IS), and others. Results indicated the following: 1) All respondents had the highest preference for relaxing spaces except DS. 2) Differences were found between DS, SFS, and LS by age and SS; IS by residential area; and DS, SS, and IS by household size. 3) People aged 60+ preferred a living room while people aged 40-59 preferred a larger kitchen. Seoul citizens preferred gardens or parks in the complex or neighboring forests whereas local citizens preferred shared offices and medical centers. Households of three or more persons preferred a park/forest and two-person households preferred a honbap restaurant. The implications for housing policy are as follows. 1) Nature-friendly spaces are needed to alleviate a sense of isolation. 2) Changing demand for residential space should be reflected in housing policies. 3) The government's housing supply policy with the same residential space and structure must be changed to provide various residential spaces according to age, residential area, and household size.

• Journal of Species Research
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• v.10 no.1
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• pp.23-45
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• 2021

For the collection of indigenous prokaryotic species in Korea, 77 strains within the phylum Actinobacteria were isolated from various environmental samples, fermented foods, animals and clinical specimens in 2019. Each strain showed high 16S rRNA gene sequence similarity (>98.8%) and formed a robust phylogenetic clade with actinobacterial species that were already defined and validated with nomenclature. There is no official description of these 77 bacterial species in Korea. The isolates were assigned to 77 species, 31 genera, 18 families, 14 orders and 2 classes of the phylum Actinobacteria. All the strains except one Coriobacteriia strain were affiliated within the class Actinomycetia. Among them, the orders Streptomycetales and Microbacteriales were predominant. A number of strains were isolated from forest soils, riverside soils, and ginseng cultivated soils. Twenty-nine strains were isolated from 'Protected Ecosystem and Scenery Areas'. Morphological properties, basic biochemical characteristics, isolation source and strain IDs are described in the species descriptions.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.603-622
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• 2023

Human error (HE) is an important concern in safety-critical systems such as nuclear power plants (NPPs). HE has played a role in many accidents and outage incidents in NPPs. Despite the increased automation in NPPs, HE remains unavoidable. Hence, the need for HE detection is as important as HE prevention efforts. In NPPs, HE is rather rare. Hence, anomaly detection, a widely used machine learning technique for detecting rare anomalous instances, can be repurposed to detect potential HE. In this study, we develop an unsupervised anomaly detection technique based on generative adversarial networks (GANs) to detect anomalies in manually collected surveillance data in NPPs. More specifically, our GAN is trained to detect mismatches between automatically recorded sensor data and manually collected surveillance data, and hence, identify anomalous instances that can be attributed to HE. We test our GAN on both a real-world dataset and an external dataset obtained from a testbed, and we benchmark our results against state-of-the-art unsupervised anomaly detection algorithms, including one-class support vector machine and isolation forest. Our results show that the proposed GAN provides improved anomaly detection performance. Our study is promising for the future development of artificial intelligence based HE detection systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.2
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• pp.494-510
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• 2024

Internet users are exposed to sophisticated cyberattacks that intrusion detection systems have difficulty detecting. Therefore, research is increasing on intrusion detection methods that use artificial intelligence technology for detecting novel cyberattacks. Unsupervised learning-based methods are being researched that learn only from normal data and detect abnormal behaviors by finding patterns. This study developed an anomaly-detection method based on unsupervised machines and deep learning for a network intrusion detection system (NIDS). We present a hybrid anomaly detection approach based on unsupervised learning techniques using the autoencoder (AE), Isolation Forest (IF), and Local Outlier Factor (LOF) algorithms. An oversampling approach that increased the detection rate was also examined. A hybrid approach that combined deep learning algorithms and traditional machine learning algorithms was highly effective in setting the thresholds for anomalies without subjective human judgment. It achieved precision and recall rates respectively of 88.2% and 92.8% when combining two AEs, IF, and LOF while using an oversampling approach to learn more unknown normal data improved the detection accuracy. This approach achieved precision and recall rates respectively of 88.2% and 94.6%, further improving the detection accuracy compared with the hybrid method. Therefore, in NIDS the proposed approach provides high reliability for detecting cyberattacks.