• Journal of the Korean Chemical Society
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• v.36 no.4
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• pp.540-545
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• 1992

Kinetics and mechanism on the solvent extraction of nickel(Ⅱ) with 8-hydroxyquinoline (HOx) was studied spectrophotometrically. Absorbance variation was measured by changing the 8-hydroxyquinoline concentration in the chloroform organic phase and the pH values in the aquous phase. By analyzing absorbance data the reaction rate was found to be the first order for 8-hydroxyquinoline concentration and the inverse first one for [H$^+$]. Therefore the rate determining step of the extraction reaction is the formation of the one-to-one metal chelate NiOx$^+$ and the rate equation is as follows; -d[Ni$^{2+}$]/dt = k[Ni$^{2+}$][Ox$^-$] = k'[Ni$^{2+}$][HOx]$_0$/[H$^+$]. The value of k' was evaluated from the slope of plot of log [Ni$^{2+}$]$_0$/[Ni$^{2+}$]$_t$ versus time and the rate constant k was calculated according to the equation k' = k ${\times}$ K$_{HOx}$ / K$_{D,HOx}$. From the temperature dependence of the extraction rate, the activation energy E$_a$ = 6.26 kcal/mol is calculated, and activation parameters, ${\Delta}$G$^{\neq}_{298}$ = 6.59 kcal/mol, ${\Delta}$H$^{\neq}_{298}$ = 5.68 kcal/mol, ${\Delta}$S$^{\neq}_{298}$ = -3.09 eu/mol are estimated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6856-6862
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• 2014

Web usage mining is a method to extract meaningful patterns based on the web users' log data. Most existing patterns of web usage mining, however, do not consider the users' diverse inclination but create general models. Web users' keywords can have a variety of meanings regarding their tendency and background knowledge. This study evaluated the extraction web-user's pattern after collecting and analyzing the web usage information on the users' keywords of interest. Web-user's pattern can supply a web page network with various inclination information based on the users' keywords of interest. In addition, the Web-user's pattern can be used to recommend the most appropriate web pages and the suggested method of this experiment was confirmed to be useful.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.953-957
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• 2002

Volatile compounds from shrimp whole body (SWB) and shrimp shell waste (SSW) were isolated, and identified by the combination of SDE (simultaneous steam distillation and solvent extraction), GC (gas chromatography, HP-5890 plus)and MSD (mass selective detecter) or olfactometry. The peak numbers isolated from SWB and SSW were 20 and 46, respectively. The amounts of the volatile compounds isolated from SSW were higher than those of SWB. SWB produced more low-boiling compounds below 7$0^{\circ}C$ and SSW did more high boiling compounds over 10$0^{\circ}C$. The volatile compounds identified from SSW were 9 pyrazines,5 acids,4 aldehydes, and 4 alcohols. These volatile compounds were evaluated by aroma extraction dilution analysis and gas chromatography olfactometry (GCO). Some compounds which were not detected by GC-FID and GC-MSD were found to be a strong shrimp flavor of log$_3$ FD 3 value by GCO. Strong shrimp odors were detected in low temperature while nutty aromatic odors and unpleasant oily smells were found in high temperature.

• Journal of Microbiology and Biotechnology
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• v.26 no.12
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• pp.2051-2059
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• 2016

To date, there has been no employment of a magnetoelastic (ME) biosensor method to detect Salmonella enterica serovar Typhimurium in soil. The ME biosensor method needs to be investigated and modified for its successful performance. The filtration method, cation-exchange resin method, and combinations of both methods were employed for the extraction of S. Typhimurium from soil. The number of S. Typhimurium and the resonant frequency shift of the ME sensor were then compared using a brilliant green sulfa agar plate and an HP 8751A network analyzer. A blocking study was performed using bovine serum albumin (BSA), polyethylene glycol (PEG), and casein powder suspension. Finally, the modified ME biosensor method was performed to detect S. Typhimurium in soil. The number of S. Typhimurium was significantly decreased from 7.10 log CFU/soil to 4.45-4.72 log CFU/soil after introduction of the cation-exchange resin method. The greatest resonant frequency shift of the measurement sensor was found when employing centrifugation and filtration procedures. The resonant frequency shift of the PEG-blocked measurement sensor was $3,219{\pm}755Hz$, which was significantly greater than those of the BSA- and casein-blocked ME sensor. The optimum concentration of PEG was determined to be 1.0 mg/ml after considering the resonant shift and economic issue. Finally, the modified ME biosensor method was able to detect S. Typhimurium in soil in a dose-response manner. Although these modifications of the ME biosensor method sacrificed some advantages, such as cost, time effectiveness, and operator friendliness, this study demonstrated a novel approach of the ME biosensor method to detect S. Typhimurium in soil.

• Journal of Sensor Science and Technology
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• v.10 no.2
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• pp.91-100
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• 2001

A $8{\times}8$ foveated (log-polar) retina chip for edge detection has been designed and fabricated using CMOS technology. Retina chip performs photo-input sensing, edge extraction and motion detection and we focused edge extraction. The pixel distribution follows the log-polar transform having more resolution in the center than in the periphery and can reduce image information selectively. This kind of structure has been already employed in simple image sensors for normal cameras, but never in edge detection retina chip. A scaling mechanism is needed due to the different pixel size from circumference to circumference. A mechanism for current scaling in this research is channel width scaling of MOS transistor. The designed chip has been fabricated using standard $1.5{\mu}m$ single-poly double-metal CMOS technology.

• Journal of Food Hygiene and Safety
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• v.37 no.4
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• pp.271-276
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• 2022

This study aimed to investigate microbial contamination of Dutch coffee in Gyeonggi province, South Korea. A total of 70 different Dutch coffee were purchased from an offline market (food service business operator). Two types of coffee were considered: "coffee made from food service business operator" and "coffee made from food manufacturer." The levels of total aerobic bacteria were 0.74-6.21 log CFU/mL in 15 samples and fungi were 0.70-4.00 log CFU/mL in 21 samples. Total aerobic bacteria was detected at higher levels in "coffee made from food service business operator" than in "coffee made from food manufacturer," and the difference was not significant. Three samples in "coffee made from food manufacturer" exceeded the standard for total aerobic bacteria. Escherichia coli, Coliform, and 12 types of foodborne bacteria were not detected in all samples. The extraction method detected no difference in cell counts of total aerobic bacteria and fungi. Therefore, to reduce microbial contamination of Dutch coffee, managing hygiene while maintaining the refrigeration temperature from the bean management stage to the sale process is crucial.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.06a
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• pp.306-315
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• 2002

With the rapid growth of WWW, the existing systems are integrated into web and various web-based systems are developed. Unlike the general applications, web aplications are developed by combining the various technologies and have their own complexities. So, we have much difficulties in the development and maintenance of web applications. To accommodate to the rapidly changing business environments and user requirements, the continuos evolution is required. In this paper, we present a method for supporting the effective development and maintenance of web applications. Our method involves the extraction of web application's structure information and analyzes web log ales containing the useful information about web site. We also describe a web testing method using the attracted information and our system developed for extracting hyperlink information and analyzing web log.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1369-1374
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• 2014

In case of APT attacks, the update server is being used as a means of dissemination, the update program is running malicious code or data in applications such as anti-virus signature is vulnerable to manipulation, SW Update threat identification and prevention measures are urgently required. This paper presents a natiional and international SW update structure, update process exploits and response measures to examine, Through the extraction/analysis of a domestic famous SW update log, we are willing to select the necessary component of the normal program update to identify a white list.

• The KIPS Transactions:PartB
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• v.8B no.6
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• pp.651-656
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• 2001

In this paper, we propose Improved Self-Organized Graph(Improved SOG：$SOG^*$)thinning method, which maintains the excellent thinning results of Self-organized graph(SOG) built from Self-Organizing features map and improves the performance of modified SOG using a new incremental learning method of Kohonen features map. In the experiments, this method shows the thinning results equal to those of SOG and the time complexity O((logM)3) superior to it. Therefore, the proposed method is useful for the feature extraction from digits and characters in the preprocessing step.

• Mass Spectrometry Letters
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• v.8 no.1
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• pp.18-22
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• 2017

Products containing any one or more of 26 fragrance allergens likely to cause contact allergies, are required under the 2008 domestic cosmetic law to be labeled when their concentrations exceed a certain range. This study focuses on the comparison and development of analytical methods based on headspace-solid phase micro extraction (HS-SPME) and liquid-liquid extraction (LLE) methods followed by GC-MS/MS for 24 of the fragrance allergens excepting for two natural materials in water samples. Using the developed HS-SPME method, 15 of the 24 fragrance allergens were analyzed and 9 compounds which have relatively low $logK_{OW}$ values (below about 2.5) were not extracted, and the correlation coefficient ($r^2$) of the calibration curve for quantification showed linearity of 0.9969 or more, and the method detection limits (MDL) and the limits of quantification (LOQ) were $0.078{\sim}0.582{\mu}g/L$ and $0.261{\sim}1.940{\mu}g/L$, respectively. In the case of using the optimized LLE method, all 24 fragrance allergens were analyzed, and the correlation coefficient ($r^2$) of the calibration curve for quantification showed linearity of 0.9957 or more, MDL and LOQ were $0.020{\sim}0.138{\mu}g/L$ and $0.065{\sim}0.440{\mu}g/L$, respectively.