• Journal of KIISE:Information Networking
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• v.32 no.3
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• pp.279-290
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• 2005

Recently, as the serious damage caused by DDoS attacks increases, the rapid detection and the proper response mechanisms are urgent. However, existing security mechanisms do not effectively defend against these attacks, or the defense capability of some mechanisms is only limited to specific DDoS attacks. In this paper, we propose a detection architecture against DDoS attack using data mining technology that can classify the latest types of DDoS attack, and can detect the modification of existing attacks as well as the novel attacks. This architecture consists of a Misuse Detection Module modeling to classify the existing attacks, and an Anomaly Detection Module modeling to detect the novel attacks. And it utilizes the off-line generated models in order to detect the DDoS attack using the real-time traffic. We gathered the NetFlow data generated at an access router of our network in order to model the real network traffic and test it. The NetFlow provides the useful flow-based statistical information without tremendous preprocessing. Also, we mounted the well-known DDoS attack tools to gather the attack traffic. And then, our experimental results show that our approach can provide the outstanding performance against existing attacks, and provide the possibility of detection against the novel attack.

• Journal of Life Science
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• v.27 no.10
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• pp.1152-1160
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• 2017

A unicellular green alga was axenically isolated from a tidal pool on Ulleung-do, Korea. Morphological, molecular, and biochemical analyses revealed that the isolate belonged to Auxenochlorella protothecoides. The current study is the first record of this species in Korea. The microalgal strain was named as A. protothecoides MM0011 and its growth, lipid and pigment compositions, and biomass properties were investigated. The strain is able to thrive in a wide range of temperatures ($5{\sim}35^{\circ}C$) and to withstand up to 1.5 M NaCl. The results of GC/MS analysis showed that the isolate was rich in nutritionally important polyunsaturated fatty acids (PUFAs). Its major fatty acids were linoleic acid (27.6%) and ${\alpha}-linolenic$ acid (39.6%). Thus, this indigenous microalga has potential as an alternative source of ${\omega}3$ and ${\omega}6$ PUFAs, which currently come from fish and plant oils. Also, the HPLC analysis revealed that the value-added antioxidant, lutein, was biosynthesized as the accessory pigments by the microalga. A proximate analysis showed that the volatile matter content was 85.6% and an ultimate analysis indicated that the gross calorific value was $20.3MJ\;kg^{-1}$. Since 40.5% of total nitrogen and 27.9% of total phosphorus were removed from the medium, respectively, it also has potential as a feedstock for biofuel applications which could be coupled to wastewater treatment. In addition, the biomass may also serve as an excellent animal feed because of its high protein content (51.4%). Therefore, A. protothecoides MM0011 shows promise for application in production of microalgae-based biochemicals and as a biomass feedstock.

• Journal of Life Science
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• v.20 no.3
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• pp.430-436
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• 2010

In this study, the effects of dibenzocyclooctadiene on seed germination were investigated in pepper. Four $C_{18}$ dibenzocyclooctadiene lignans - schisandrin (1143.7 mg), schisandrin C (317.3 mg), gomisin A (261.4 mg) and gomisin N (213.4 mg) - were isolated from hexane extracts of the fruits of Schisandra chinensis. The molecular structures of the four lignans were elucidated based on spectroscopic analyses including 1D NMR experiments, and bi comparing their spectroscopic data with those of previous literatures. Seeds were immersed in $10^{-5}\;M$ schisandrin, $10^{-6}\;M$ schisandrin C and $10^{-7}\;M$ gomisin A and gomisin N for 1 hr and incubated at $25^{\circ}C$ in the dark for germination. Compared to untreated control, treatment with schisandrin C and gomisin A suppressed seed germination at 48 hrs after incubation, whereas treatment with gomisin N increased germination rate at 48 hrs after incubation. The results of the germination activity of the lignans from S. chinensis confirm their potential plant growth role, and the relative natural abundances of these metabolites suggest their potential use as natural plant growth regulators.

• Korean Journal of Food Science and Technology
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• v.37 no.6
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• pp.882-888
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• 2005

Procedure for analysis of methylmercury in fish was developed, involving addition of HCl, extraction with toluene, and clean-up using L-cystein solution. Obtained extract is analyzed by gas chromatography with electron capture detector using Ulbon HR-Thermon-Hg column. Detection limit and recovery of the method were 0.005mg/kg (expressed as Hg), 98-107 (103%), respectively. Total mercury and methylmercury concentrations in 175 commercial fish samples ranged from [mean-max (mean), unit: mg/kg]: 0.014-1.200 (0.270) and 0.006-0.901 (0.168) in tuna-fish, 0.020-0.934 (0.323) and 0.012-0.553 (0.149) in martin-fish, 0.082-0.782 (0.391) and 0.040-0.436(0.201) in shark, 0,023-0.031 (0.026) and 0,013-0.018 (0.015) in salmon, 0.098-0.193 (0.133) and 0.031-0.015(0.090) in tilefish, and 0,031-0.214 (0.089) and 0.016-0.093 (0.042) in canned tuna respectively. No sample of analyzed fish exceeded 1.0mg/kg wet wt., limit for methylmercury established by Codex. In all species examined, estimated weekly intake was lower than Provisional Tolerable Weekly Intake recommended by the JECFA (the Joint FAO/WHO Expert Committee on Food Additives).

• Journal of Life Science
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• v.26 no.8
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• pp.936-942
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• 2016

As the incidence of environmental diseases is increasing due to harmful environmental factors, there is a rising interest in developing eco-friendly materials for housing. In this study, we sought to develop antimicrobial interior fabric blind materials by employing ethanol extract of a medicinal plant Zanthoxylum piperitum DC. As determined by the disc diffusion method, the zones of inhibition of the pericarp ethanol extract at a concentration of 5 mg/disc against Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus mutans were 13.5±1.5 mm, 14.0±0.5 mm and 15.0±0.1 mm, respectively, whereas the leaf ethanol extract (5 mg/disc) against K. pneumoniae, S. aureus, and S. mutans were 12.8± 0.3 mm, 13.5±1.0 mm, and 12.0±0.1 mm, respectively. The IC₅₀ of the leaf ethanol extract against K. pneumoniae, S. aureus and S. mutans were about 0.5 mg/ml, 0.1 mg/ml and 1.0 mg/ml respectively. To examine whether the leaf ethanol extract possessing antibacterial activity of Z. piperitum DC can be applicable to production of antimicrobial fabric blind materials, the fabrics treated with either 1.0% or 2.0% of the leaf ethanol extract were tested for antibacterial activity against K. pneumoniae and S. aureus using International Standard Fabrics Test Method. The results indicate that the fabric treated with the ethanol extract of Z. piperitum DC possesses an excellent antimicrobial activity against both pathogenic bacteria. These results suggest that Z. piperitum DC may be applicable to producing functional fabrics which are effective in reducing the harmful bacterial factors in indoor environments.

• Journal of agriculture & life science
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• v.45 no.4
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• pp.1-11
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• 2011

The aim of this study was development of natural antifungal compounds from softwood. We investigated antifungal activities of extracts from Pseudotsuga menziesii and Chamaecyparis obtusa against Tricholderma genus which is virus causing green mold disease and analyzed antifungal compounds by Gas chromatography -Mass Spetrometer. Extracts from P. menziesii had inhibition activities against Tricholderma genus on 1,000 ppm and had high antifungal activities against T. viride by 70.1%, T. harzianum by 67.3% and T. aggressivum by 64.7% on 4,000 ppm. And extracts from C. obtusa had antifungal activities against Tricholderma genus on 1,000 ppm and had high antifungal activities against T. viride by 63.2%, T. harzianum by 59.3% and T. aggressivum by 59.1% on 4,000 ppm. But mixing compounds which are made from P. menziesii and C. obtusa extracts by variety ratio had lower antifungal activities than original extracts. Main antifungal active components of P. menziesii extracts against Tricholderma genus were 2-Isopropoxy-ethylamine 46.5%, epifluorohydrin 8.6%, trans-2,3-Di-methyloxirane 7.6%, (IR)-(-)-Myrtenal 6.0%, 2-Methoxy-4-Vinylphenol 3.9% and benzaldehyde 2.8%. In case of C. obtusa extracts, they were ${\alpha}$-Terpinenyl acetate 14.9%, Sabinene 10.9%, dl-Limonene 9.6%, ${\alpha}$-Terpinolene 7.5% and ${\alpha}$-Pinene 7.1%. As mentioned above, these results revealed extracts from P. menziesii and C. obtusa of softwood could be used as potential agents to inhibit Trichoderma genus.

• Journal of Food Hygiene and Safety
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• v.34 no.2
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• pp.191-198
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• 2019

This study investigated the residual characteristics of bifenthrin and chlorothalonil in crown daisy and suggested pre-harvest residue limits (PHRLs) based on their dissipation patterns and biological half-lives. The samples for residue analysis were harvested at 0 (3 hr), 1, 3, 5, 7, 9, 11, 13, 15, 18, 22 and 26 days after treatment, and analyzed by $GC/{\mu}-ECD$ and TOF/MS. The limit of quantitation (LOQs) of bifenthrin and chlorothalonil were 0.0046 mg/kg and 0.0007 mg/kg, respectively. Recoveries ranged from $88.67{\pm}7.97%$ and $99.90{\pm}16.03%$, showing that this method is appropriate for the analysis of the pesticide residues in crown daisy. Being well within first order kinetics, the biological half-lives of the pesticide residues in crown daisy were 9.63 days for bifenthrin and 6.54 days for chlorothalonil. The PHRLs of bifenthrin and chlorothalonil were recommended as 11.70 mg/kg and 24.10 mg/kg for 26 days before harvest, respectively.

• Journal of Apiculture
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• v.32 no.3
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• pp.139-146
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• 2017

Floral scent emitted from many plants is the critical factors for pollinator attraction and defense for adaptation in environments. The fragrance components of flowers are different in composition by geographical origins, climate factors and the development stages of flowers. In the present study, we investigated the volatile-floral compounds in flowers of Robinia pseudoacacia L. and defined the chemical contribution for flowering periods. The volatile compounds analysis was performed by gas chromatography with mass selective detector after solid phase microextraction (SPME). We reported different compositional features of fragrance compounds according to flowering periods. The abundant compounds identified in stage 1 were ${\alpha}$-pinene (66.80%) and ${\beta}$-pinene (26.53%). Those of the stage 2 were (Z)-${\beta}$-ocimene (37.57%), ${\alpha}$-pinene (15.16%), benzaldehyde (16.63%), linalool (12.13%). The volatiles of stage 3 comprised an abundance of (Z)-${\beta}$-ocimene (64.94%), ${\alpha}$-pinene (9.84%), linalool (8.92%), benzaldehyde (1.71%). Leaf volatiles were distinct from those in the reproductive plant parts by their high relative amount of (E)-${\beta}$-ocimene (23.50%) and (Z)-3-Hexenyl acetate (27.87%). Differences in flower scents of the different stages and leaves are discussed in light of biochemical constraints on volatile chemical synthesis and of the role of flower scent in evolutionary ecology of R. pseudoacacia.

• Korean Journal of Food Science and Technology
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• v.52 no.6
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• pp.565-572
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• 2020

The 3-monochloropropane-1,2-diol (3-MCPD) is a contaminant that occurs in foodstuffs in its free form as well as in its bound form. The objective of this study was to evaluate the effects of emulsifier, frying temperature, and the amounts of salt and oil on the formation of bound 3-MCPD in a fried snack model. Emulsifier affected the formation of bound 3-MCPD; furthermore, it was observed that the largest amount of bound 3-MCPD was detected in the fried snack model when glycerin esters of fatty acids were used as emulsifiers. Frying temperature also affected the formation of bound 3-MCPD, which increased significantly as the frying temperature increased from 145 to 190℃. In addition, salt affected the formation of bound 3-MCPD. As the amount of salt increased, the amount of bound 3-MCPD also increased significantly. Moreover, it was observed that the amount of oil did not affect the formation of bound 3-MCPD. These results will aid in the reduction of bound 3-MCPD in fried snacks.

• Korean Journal of Remote Sensing
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• v.38 no.6_3
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• pp.1817-1826
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• 2022

After the hydrogen fluoride leak in Gumi in 2012, the government has been systemizing the disaster management system, such as responding to and managing chemical accidents. In particular, the Ministry of the Interior and Safety (MOIS) is in charge of evacuation of residents following chemical accidents based on the Framework Act on Management of Disaster and Safety. In this study, an application plan was presented to support and utilize the decision-making support for evacuation of residents after a chemical accident using the chemical accident investigation equipment of the National Disaster Management Research Institute (NDMI). In the equipment operation system for scientific information collection due to chemical accidents, the roles and purpose of use of long/short distance measurement equipment were presented according to regular and emergency situations. Using the data acquired through long/short distance measurement equipment, it can be used as basic data for resident evacuation decision-making by monitoring whether chemicals are detected in an emergency and managing data on detected substances by company in a regular situation. As a result of measuring chemical substances in order to verify on-site usability by equipment only for the regular operation system, it was confirmed that real-time detection of chemical substances is possible with long distance measuring equipment. In addition, it was confirmed that it was necessary to check the measurable distance and range of the equipment in the future. In the case of short distance measurement equipment, hydrocarbon-based substances were mainly detected, and it was confirmed that it was measured at a higher level in Ulsan-Mipo National Industrial Complex than in Onsan National Industrial Complex. It is expected that it can be used as basic data to support decision-making in the event of chemical accidents through continuous data construction in the future.