• Korean Journal of Food Science and Technology
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• v.42 no.3
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• pp.287-291
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• 2010

In this study, a simple and rapid pre-treatment method based on liquid extraction was applied for the simultaneous determination of three macrolides (spiramycin, tylosin, and tilmicosin) residues. In these studies, the stock farm products was used as a matrix sample. When the liquid extraction method was compared with the solid phase extraction (SPE) method, the former showed higher recovery percentages and simpler steps than the latter. The macrolids were separated using a reverse-phase C18 ($250\;mm{\times}4.6\;mm$, $5\;{\mu}m$) column and a gradient elution with mobile phases consisting of phosphate buffer (pH 2.5) and acetonitrile. Tylosin and tilmicosin were detected at 288 nm and spiramycin was detected at 232 nm. The average recovery percentage ranged between 83.0-90.2% for samples spiked with the three macrolids at 50 and 100 ng/g The validation results showed that the limit of detection (7 (spiramycin), 12 (tilmiconsin), 12 (tylosin) ng/g)) was under the regulatory tolerances and the linearity from calibration curves was satisfactory for determining the multi-residue of three macrolids in farm products. Monitoring samples were collected at the main cities in Korea as Seoul, Busan, Deajeon, Incheon, Deagu, and Gwangju. Microlide antibiotics were not detected in most samples.

• Journal of Intelligence and Information Systems
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• v.17 no.4
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• pp.143-155
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• 2011

Lately electronic tagging policy for the sexual offenders was introduced in order to reduce and prevent sexual offences. However, most sexual offences against children happening these days are committed by the tagged offenders whose identities have been released. So, for the crime prevention, we need measures with which we could minimize the suffers more promptly and actively. This paper suggests a new system to relieve the sexual abuse related anxiety of the children and solve the problems that electronic bracelet has. Existing bracelets are only worn by serious criminals, and it's only for risk management and positioning, there is no way to protect the children who are the potential victims of sexual abuse and there actually happened some cases. So we suggest also letting the students(children) wear the LBS(Location Based Service) and USN(Ubiquitous Sensor Network) technology based electronic bracelets to monitor and figure out dangerous situations intelligently, so that we could prevent sexual offences against children beforehand, and while a crime is happening, we could judge the situation of the crime intelligently and take swift action to minimize the suffer. And by checking students' attendance and position, guardians could know where their children are in real time and could protect the children from not only sexual offences but also violent crimes against children like kidnapping. The overall system is like follows : RFID Tag for children monitors the approach of offenders. While an offender's RFID tag is approaching, it will transmit the situation and position as the first warning message to the control center and the guardians. When the offender is going far away, it turns to monitoring mode, and if the tag of the child or the offender is taken off or the child and offender stay at one position for 3~5 minutes or longer, then it will consider this as a dangerous situation, then transmit the emergency situations and position as the second warning message to the control center and the guardians, and ask for the dispatch of police to prevent the crime at the initial stage. The RFID module of criminals' electronic bracelets is RFID TAG, and the RFID module for the children is RFID receiver(reader), so wherever the offenders are, if an offender is at a place within 20m from a child, RFID module for children will transmit the situation every certain periods to the control center by the automatic response of the receiver. As for the positioning module, outdoors GPS or mobile communications module(CELL module)is used and UWB, WI-FI based module is used indoors. The sensor is set under the purpose of making it possible to measure the position coordinates even indoors, so that one could send his real time situation and position to the server of central control center. By using the RFID electronic roll book system of educational institutions and safety system installed at home, children's position and situation can be checked. When the child leaves for school, attendance can be checked through the electronic roll book, and when school is over the information is sent to the guardians. And using RFID access control turnstiles installed at the apartment or entrance of the house, the arrival of the children could be checked and the information is transmitted to the guardians. If the student is absent or didn't arrive at home, the information of the child is sent to the central control center from the electronic roll book or access control turnstiles, and look for the position of the child's electronic bracelet using GPS or mobile communications module, then send the information to the guardians and teacher so that they could report to the police immediately if necessary. Central management and control system is built under the purpose of monitoring dangerous situations and guardians' checking. It saves the warning and pattern data to figure out the areas with dangerous situation, and could help introduce crime prevention systems like CCTV with the highest priority. And by DB establishment personal data could be saved, the frequency of first and second warnings made, the terminal ID of the specific child and offender, warning made position, situation (like approaching, taken off of the electronic bracelet, same position for a certain time) and so on could be recorded, and the data is going to be used for preventing crimes. Even though we've already introduced electronic tagging to prevent recurrence of child sexual offences, but the crimes continuously occur. So I suggest this system to prevent crimes beforehand concerning the children's safety. If we make electronic bracelets easy to use and carry, and set the price reasonably so that many children can use, then lots of criminals could be prevented and we can protect the children easily. By preventing criminals before happening, it is going to be a helpful system for our safe life.

• Korean Journal of Veterinary Service
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• v.38 no.2
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• pp.127-136
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• 2015

A simultaneous determination method was developed for nine preservatives (benzoic acid, sorbic acid, dehydroacetic acid, methyl-, ethyl-, isopropyl-, propyl-, isobutyl- and butyl-parabens) in sausage by liquid chromatography with electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS). Each parameter was established by multiple reaction monitoring in negative mode. Separation was achieved on a phenyl-hexyl ($2.5{\mu}m$, $2.1{\times}150mm$, Waters) with A-20 mM ammonium acetate containing 0.1% acetic acid in water, B-Acetonitrile as mobile phase with gradient mode at a flow rate of 0.3 mL/min. The developed method was validated for specificity, linearity, accuracy and precision in sausages samples. Linearity was over 0.998 with calibration curve of the mixed standards. The mean recoveries from sausages fortified at the level of 2.0~10.0 mg/L were in range of 98.60~109.16% with RSDs lower than 8.93%. The limits of detection (LOD) and the limits of quantification (LOQ) were in the range between 0.0003~0.085 mg/L and 0.01~0.257 mg/L, respectively. Intra-day precision and inter-day precision were 0.45~6.16% and 2.81~13.33%, respectively. Using presently developed determination method, 33 field sausage samples from Gwangju city in Korea were screened over nine preservatives. As a result, no preservatives were detected in all samples.

• Spatial Information Research
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• v.22 no.4
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• pp.67-76
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• 2014

Recently, through the development of IT and mobile technology, spatial information plays a role of infrastructure of the people life and the national economy. Many kinds of applications including SNS and social commerce is to leverage the spatial information for their services. In the case of domestic, spatial open platform that can provide national spatial data infrastructure services in a stable manner has been released. And many people have been interested to the open platform services. However, the open platform currently has many difficulties to analyze its service status and load in real time, because it does not hold a real-time monitoring system. Therefore, we propose a method that can analyze the real-time service status of the open platform using the analysis of the web server log information. In particular, we propose the results of the analysis as follows: amount of data transferred, network bandwidth, number of visitors, hit count, contents usage, and connection path. We think the results presented in this study is insufficient to understand the perfect service status of the open platform. However, it is expected to be utilized as the basic data for understanding of the service status and for system expansion of the open platform, every year.

• The Journal of the Korea Contents Association
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• v.20 no.4
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• pp.396-405
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• 2020

In this study, we used the big data of Voice of Customer (VOC) related to high-speed Internet products to look at the causes of perceived quality and the possibility of proactive service. In order to verify the possibility of proactive service, we collected VOC data from 13 facilities and equipment of a mobile communication service company, and then conducted 𝒙² test to verify that there was a statistically significant difference between the actual VOC observation values and expected values. We found statistical evidence that proactive service is possible through real-time monitoring for the six disability alarms among the 13 facilities and equipment, which are FTTH-R Equipment ON/OFF, FTTH-EV Line Error Detection, Port Faulty, FTTH-R Line Error Detection, Network Loop Detection, and Abnormal Limiting Traffic. Companies are able to adopt the proactive service to improve their market share and to reduce customer service costs. The results of this study are expected to contribute to the actual application of industry in that it has diagnosed the possibility of proactive service in the telecommunication service sector and further suggested suggestions on how to provide effective proactive service.

• Food Science of Animal Resources
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• v.35 no.6
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• pp.765-771
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• 2015

The development of a sample preparation method and optimization of the analytical instrumentation conditions were performed for the determination of the vitamin B₁₂ content in emulsified baby foods sold on the Korea market. After removal of the milk protein and fats by chloroform extraction and centrifugation, the vitamin B₁₂ was water extracted from the sample. Following filtration of the solution through a nylon filter, the water-soluble extract was purified by solid-phase extraction using a Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS). The solution eluted from the cartridge was dried under a stream of nitrogen gas and reconstituted with 1 mL of water. The sample solution was injected into an LC-MS/MS system after optimizing the mobile phase for vitamin B₁₂ detection. The calibration curve showed good linearity with the coefficient of correlation (r²) value of 0.9999. The limit of detection was 0.03 µg/L and the limit of quantitation was 0.1 µg/L. The method of detection limit was 0.02 µg/kg. The vitamin B₁₂ recovery from a spiking test was 99.62% for infant formula and 99.46% for cereal-based baby food. The sample preparation method developed in this study would be appropriate for the rapid determination of the vitamin B₁₂ content in infant formula and baby foods with emulsified milk characteristics. The ability to obtain stable results more quickly and efficiently would also allow governments to exercise a more extensive quality control inspection and monitoring of products expected to contain vitamin B₁₂. This method could be implemented in laboratories that require time and labor saving.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.2021-2026
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• 2009

Toluene, xylene and styrene are volatile organic solvents that are commonly used in mixtures in many industries. Because these solvents are metabolized and then excreted in urine, their urinary metabolites are thought to be biomarkers of occupational exposure to these solvents. Therefore, a simple, rapid, and yet reliable analytical method for determining the metabolites is required for accurate biological monitoring. In the present study, a simple and rapid HPLC-UV method was developed for the simultaneous determination of eight major metabolites of toluene, xylene and styrene: hippuric acid (HA), mandelic acid (MA), o-, m- and p-methylhippuric acids (o-, m- and p-MHAs), and o-, m- and p-cresols. A monolithic column was employed as the stationary phase and several conditions, including flow rate, composition of mobile phase and column temperature, were variables for the optimization of the chromatographic resolution. All eight metabolites were successfully resolved within 5 minutes in 10% aqueous ethanol containing 0.3% acetic acid and 1.6% $\beta$-cyclodextrin, using a flow rate gradient of 1.0 - 5.0 mL/min at 25 ${^{\circ}C}$. The performance of this method was validated by linearity, intra- and inter-day accuracy, and precision. The linearity was observed with correlation coefficients of 0.9998 for HA, 0.9999 for MA, 0.9989 for o-MHA, 0.9998 for m-MHA, 0.9991 for p-MHA, 0.9997 for o-cresol, 0.9998 for m-cresol, and 0.9986 for p-cresol. The intra- and inter-day precision of the method were less than 5.89% (CV) and the accuracy ranged from 92.95 to 106.62%. The validity was further confirmed by analysis of reference samples that were prepared by the inter-laboratory quality assurance program of the Korea Occupational Safety and Health Agency (KOSHA, Seoul, Korea). All measured concentrations of the analytes agreed with the certified values.

• Ecology and Resilient Infrastructure
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• v.3 no.3
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• pp.169-176
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• 2016

Roads are widely accepted to be as a major cause of habitat fragmentation. The wildlife road-crossing structure is one of the most acceptable alternatives among the solutions to provide connectivity between patches isolated by roads. We investigated noise disturbance, vegetation structure and wildlife crossing and habitation at a wildlife road-crossing structure located at the Jingmaei-Pass in Incheon, Korea, to monitor and evaluate its conservation value and ecological performance and to propose measures for their adaptive management. From the result of noise measurement, the noise disturbance from the road traffic was not properly blocked out at the wildlife crossing structure. The survey results of vegetation structure showed that the early-successional plant species such as Ambrosia trifida, Erigeron annuus, Pueraria lobata, Rosa multiflora invaded widely on the crossing structure. An efficient management of the vegetation should be necessarily considered for the facilitation of vegetation succession and the improvement of animal habitat. The crossing structure was used by limited mammal species: Apodemus agrarius, Nyctereutes procyonoides, Mogera wogura and Sciurus vulgaris coreae as the results of the monitoring using footprints and closed-circuit television. In conclusion, The Jingmaei-Pass wildlife crossing structure is unable to function properly as a biological corridor because of the interference of noise and flourishing disturbed vegetation. Therefore, proper alternatives are required for improving animal habitats and mobile environments to enhance the ecological function of a wildlife corridor.

• Journal of Food Hygiene and Safety
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• v.33 no.1
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• pp.58-64
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• 2018

An analytical method for the determination of cephalexin (CEX) in bovine tissues (muscle, liver, kidney and fat tissues) was developed and validated using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Tissue samples were extracted by the liquid-liquid extraction based on 5% trichloroacetic acid (TCA). The chromatographic separation was achieved on a reverse phase $C_{18}$ column with gradient elution using a mobile phase of 20 mM hexafluroacetylacetone (HFAC)/50% acetonitrile (40:60). The procedure was validated according to the Ministry of Food and Drug Safety guideline determining accuracy, precision, and limit of detection. Mean recoveries of CEX from spiked edible tissues ($6{\sim}1,500{\mu}g/kg$) were 83.9~106.8%, and the relative standard deviation was between 2.3 and 14.8%. Linearities were obtained with the correlation coefficient ($r^2$) of > 0.999. Limit of detection and limit of quantification for the investigated CEX were 2~10 and $6{\sim}30{\mu}g/kg$, respectively. This method was reliable, sensitive, economical and suitable for routine monitoring of CEX residues in bovine edible tissues.

• Journal of Pharmaceutical Investigation
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• v.41 no.4
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• pp.255-262
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• 2011

Method using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed and validated for the determination of pregabalin in plasma samples. Acquisition was performed by monitoring the transitions: m/z 160.1${\rightarrow}$142.2 for pregabalin and m/z 423.2${\rightarrow}$207.1 for losartan (as an internal standard). After cold acetonitrileinduced protein precipitation of the plasma samples, separation was performed with C18 column by isocratic mobile phase consisted of 10 mM ammonium acetate and acetonitrile (15:85, v/v). Results were linear over the concentration ranged from 0.1 to $10{\mu}g$/mL and the correlation coefficients (r) were $\geq0.99$. Intra- and inter-day precisions were $\leq6.02$ and $\leq11.04%$, respectively, and intra- and inter-day accuracies were 96.60-101.09 and 98.10-102.60%, respectively. This validated method was successfully applied to a bioequivalence study of two formulations of pregabalin, Daewoong pregabalin capsule (Daewoong Pharm. Co., Ltd.) and Lyrica$^{(R)}$ capsule (Pfizer Korea Ltd.) in twenty eight healthy Korean volunteers. The subjects received a single oral dose of each formulation (150 mg as pregabalin) in a randomized $2{\times}2$ crossover study and plasma samples were obtained from each subject at predetermined time intervals. Then, the pharmacokinetic parameters ($AUC_{0-t}$, $C_{max}$ and $T_{max}$) were calculated and statistically analyzed to assess the differences between two formulations. The 90% confidence intervals for the log-transformed data were acceptable range of log 0.8-log 1.25 (e.g., log 1.0048-log 1.0692 for AUC0-t, log 0.9142-log 1.0421 for $C_{max}$). Thus, $AUC_{0-t}$ and $C_{max}$ met the criteria of the Korea Food and Drug Administration (KFDA) for bioequivalence test indicating that Daewoong pregabalin capsule was bioequivalent to Lyrica$^{(R)}$ capsule.