• Journal of Food Hygiene and Safety
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• v.31 no.1
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• pp.15-20
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• 2016

Malachite green was measured in 200 freshwater fish collected from local markets in Seoul using HPLC-DAD and LC-MS/MS. LC-MS/MS method was validated by linearity, accuracy, precision and limits of detection and quantification according to the CODEX's recommendation and HPLC-DAD method was applied according to the Food Code. Malachite green levels above the quantification limit of the LC-MS/MS were determined 18.5% (37) but just 1 fish was shown to contain malachite green by HPLC-DAD. Of 83 domestic fish, 21 fish were detected malachite green (25.3%). Of 117 fish from China, just 16 fish were detected malachite green (13.4%). In detection rate by species carp (35.0%), Crucian carp (30.4%), cat fish (28.0%), Korean bull head (23.8%), snake head (20.0%), eel (10.5%) and loach (7.8%) were in order. Especially, fish collected at summer were shown to contain malachite green frequently; the detection rate was 54.8%.

• Journal of Food Hygiene and Safety
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• v.27 no.3
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• pp.224-232
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• 2012

This study was performed to investigate the pesticide residue of commercial medicinal plants used for food materials in the Seoul area. Multi class pesticide multiresidue methods in Korea Food Code was used to analyze 100 pesticides. Analyzed samples were 261 cases(domestic 201, imported 60), detection rate was 19.2%(domestic 20.9%, imports 13.3%). 17 pesticides were detected in fruit(chinese matrimony vine, jujube, rubus coreanus, japanese cornlian cherry, schizandra, tangerine peel), and root(cnidium, licorice, astragalus). Pesticide over Maximum Residue Limits were detected in jujube, cnidium. Frequently detected pesticides were cypermethrin, chlorpyrifos, cyhalothrin, fenvalerate, bifenthrin. More than 50% of the sample were detected two or more pesticides at the same time. Because of the variety and increase of pesticide detection in medicinal roots and fruits, continued monitoring and safety management is required.

• Journal of Food Hygiene and Safety
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• v.36 no.1
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• pp.24-33
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• 2021

For this study, we surveyed concentrations of 8 mycotoxins (aflatoxin B1, B2, G1, G2, ochratoxin A, fumonisin B1, B2 and zearalenone) in agricultural products used for food and medicine by liquid chromatography-tandem mass spectrometry and conducted a risk assessment. Samples were collected at the Yangnyeong Market in Seoul, Korea, between January and November 2019. Mycotoxins were extracted from these samples by adding 0.1% formic acid in 50% acetonitrile and cleaned up by using an ISOLUTE Myco cartridge. The method was validated by assessing its matrix effects, linearity, limit of detection (LOD), limit of quantification (LOQ), recovery and precision using four representative matrices. Matrix-matched standard calibration was used for quantification and the calibration curves of all analytes showed good linearity (r2>0.9999). LODs and LOQs were in the range of 0.02-0.11 ㎍/kg and 0.06-0.26 ㎍/kg, respectively. Sample recoveries were from 81.2 to 118.7% and relative standard deviations lower than 8.90%. The method developed in this study was applied to analyze a total of 187 samples, and aflatoxin B1 was detected at the range of 1.18-7.29 ㎍/kg (below the maximum allowable limit set by the Ministry of Food and Drug Safety, MFDS), whereas aflatoxin B2, G1 and G2 were not detected. Mycotoxins that are not regulated presently in Korea were also detected: fumonisin (0.84-14.25 ㎍/kg), ochratoxin A (0.76-17.42 ㎍/kg), and zearalenone (1.73-15.96 ㎍/kg). Risk assessment was evaluated by using estimated daily intake (EDI) and specific guideline values. These results indicate that the overall exposure level of Koreans to mycotoxins due to the intake of agricultural products used for food and medicine is unlikely to be a major risk factor for their health.

• Journal of the Economic Geographical Society of Korea
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• v.11 no.4
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• pp.661-667
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• 2008

We examine the major factors governing the travel time for commuters in the Seoul metropolitan area. To identify the determinants of the commuting time for residents with jobs in the city centre, a multiple regression analysis is performed using household survey data. The results reveal that commuters in Seoul place higher value on time than on living space. Thus, we may conclude that recent trends in income segregation in Seoul are not the result of increased housing demand but of dispersed jobs and better amenities offered in the suburbs.

• Journal of Environmental Health Sciences
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• v.39 no.5
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• pp.418-425
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• 2013

Objective: This study was carried out for the purpose of identifying major substances contributing to the production of odor and evaluating the characteristic of odors. Methods: Complex odor and 17 odorous compounds were measured at 18 waste transfer stations located in Seoul. Results: The dilution ratio value of complex odor ranged from 4 to 30 times in the boundary layer of 18 waste transfer stations. At 6 measurement points among the 18 waste transfer stations, the dilution ratio values exceeded standards (15 times). When the results were evaluated in terms of their contribution to the formation of malodor, the patterns indicated that the highest concentration values in the residential waste disposal process were of i-valeraldehyde and acetaldehyde, while butyraldehyde and acetaldehyde accounted for a large proportion of odorous compounds from the waste recycling process. Conclusions: It was found that butyraldehyde and acetaldehyde were the primary compounds released from the food waste disposal process. Overall, aldehyde compounds were the greatest contributor to detectable odor intensity emitted at the waste transfer stations.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.20-36
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• 2001

The purpose of this paper is estimating environmental carving capacity of Seoul Metropolitan Area for a sustainable city management using system dynamics model. A sustainable development requires a society to define sustainability constraints or environmental limits, environmental carving capacity. Environmental carving capacity can be defined as the level of human activity which a region can sustain at an acceptable quality of life level. This concept of environmental carving capacity has several important application to sustainable city planning and management. If the limitation of a human activity can be supported by a scientific data on carving capacity, the resulting decision and actions could more easily win public support for a sustainable development. However, one of the key issues is how to operationalize the carving capacity. In this paper, the environmental carving capacity was operationalized as a maximum number of industry structure, population, and housing that can sustain certain level of environmental quality of Seoul Metropolitan Area. The model developed in this paper consisted off sectors: population, housing, industry, land, and environmental sector. The model limits its main focus on the NO$_2$level of ambient air of Seoul. Carving capacity Seoul Metropolitan Area was estimated by figuring out the maximum number of population, industry structure, housing at an equilibrium point that sustain a desirable NO$_2$level. Based on the model estimation, several policy implications for a sustainable city management was discussed.

• Journal of environmental and Sanitary engineering
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• v.15 no.4
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• pp.105-113
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• 2000

We have isolated 65 strains(2.0%) of Y. enterocolitica among 3,219 water samples from 380 spring water sites in Seoul from 1994 to 1999. The biochemical characteristics of isolated strains revealed that TSI was A/A, urea, M.R.($37^{\circ}C$), nitrate, motility($37^{\circ}C$), sorbitol, maltose, manitol, arabinose, mannose, trehalose, xylose were positive(100%) and H$_2$S, arginine, lysine, oxidase, citrate, V.P.($37^{\circ}C$), DNase, motility($37^{\circ}C$), dulcitol, adonitol, lactose and raffinose were negative(100%). In in vitro virulence test, positive rate of AAG and CRMOX were 9.2% and 4.6%, respectively. However in the virulence gene detectable gene detectable test by multiplex-PCR using ail, yst, virF genes, 65 strains were all negative, meaning that Y.enterocolitica strains from domestic spring water were not detected for the virulence. Otherwise, mutiplex-PCR which using ail, yst and subgenus-specific primer pair was the best for identifying the virulence of Y. enterocolitica.

• Journal of Urban Science
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• v.9 no.1
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• pp.17-31
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• 2020

This study aims to analyze the relations among greenbelt, urban land surface temperature empirically in order to assess the environmental effects of the greenbelt in the Seoul metropolitan area, objectively. For this purpose, this study conducts an empirical analysis of impacts of greenbelt on urban land surface temperature using a multiple-regression model. The main data employed in the analysis include real-time air pollution data, Landsat 8-OLI Landsat imagery data, KLIS data and Jip-gye-gu data. The major findings are summarized as follows. NDVI has a negative (-) correlation with the land surface temperature, and the urban temperature is high in areas with poor vegetation. The land surface temperature is low in residential or commercial areas, while the temperature is high in industrial areas. The temperature is low in green fields, open spaces, and river areas. it is found that the urban land surface temperature is low in the greenbelt zone. In the greenbelt zone, there is an effect that reduces the land surface temperature by 1% on average, as compared to that at the center of the Seoul metropolitan area. Especially, the center of the Seoul metropolitan area, in a range from 0.6% to 1.9% of the average temperature, the temperature gets lower up to approximately 3km from the greenbelt boundary.

• Journal of the Korean Operations Research and Management Science Society
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• v.14 no.2
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• pp.185-185
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• 1989

Business process reengineering(BPR) aims at a radical redesign of our business processes in order to achieve dramatic improvements in their performance. However, the fact that many BPR projects have failed hesitates the companies who have started to use BPR or who are planning to do so. Implementing a radical plan from a cross-functional perspective needs a more careful consideration of process vision, preventive measures and contingency plan. Our research suggests to use a visual decision making process (VDMP) in the development of a process vision and implementation plan. A BPR project of Carlson School of Management (CSOM) at the University of Minnesota is illustrated to show our suggested methodology.

• Journal of Food Hygiene and Safety
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• v.28 no.1
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• pp.31-35
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• 2013

In this study, the pesticide residues of polished rice and brown rice were measured after washing and cooking process. The initial concentrations of isoprothiolane and fthalide were $7.134{\pm}0.03mg/kg$ and $2.024{\pm}0.04mg/kg$ for polished rice, and $17.941{\pm}1.41mg/kg$ and $6.413{\pm}0.19mg/kg$ for brown rice, respectively. After first washing process, the removal rates of isoprothiolane were 23.0% (polished rice) and 18.5% (brown rice). Also, the case of fthalide, the removal rates were 14.0% and 9.7%, respectively. The removal dose was increased, but the removal rate was decreased in proportion to the number of washing process, After the cooking process, the removal rates of isoprothiolane and fthalide were 66.0% and 79.0% (polished rice), and 88.7% and 92.9% (brown rice), respectively. The removal rate of isoprothiolane was higher in the washing process, and the case of fthalide was higher in the cooking process. The optimum washing process for the pesticides removal was five times and the cooking process was the most effective to use the new water after soaking the rice in water during 30 minutes.