• Journal of Food Hygiene and Safety
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• v.22 no.1
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• pp.63-75
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• 2007

A survey on sanitary management at 98 food service institutions located in Jeollabuk-Do were conducted. Food service institutions included 13 hospitals, 38 schools, 40 enterprises, and 7 others. The sterilization in boiling water was used for disinfection of tableware, spoon and chopsticks, and dish towel. Cooking kit, refrigerator, chopping board, and knife were sterilized with disinfectant. Frequency of sanitary training program on employees was 56.1% for 1 time/month, 12.2% for 2-3 times/month, and 11.3% for 1 time/week. Preparing ratio of defrosting, warehouse and rest room, and washing and sterilization diary were 73.8, 60.5, and 54.5%, respectively. However, checking ratio of environments (9.5%), personal sanitation (10.8%), and sanitary training program diary(8.4%) were low. Major obstacle factors on the introduction of Hazard analysis critical control point (HACCP) system into food service institutions were lack of equipment and facilities (54.1%) and lack of understanding and data on HACCP system (17.3%). Therefore, in order to reduce the outbreak of food-borne diseases increasing frequency, we estimated that the introduction of sanitary management system and the conversion of dietician' perception on sanitary managements in food service institutions were needed.

• Smart Media Journal
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• v.9 no.2
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• pp.16-21
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• 2020

Recently, mobile traffic is increasing exponentially as major traffic is transferred to IoT and visual media data in the dissemination of mobile communication terminals and contents use. In order to overcome the limitations of the existing LTE system, 5G mobile communication technology (5G) is a technology that meets 1000 times data traffic capacity, 4G LTE system acceptance, low latency, high energy efficiency, and high cost compared to 4G LTE system. The path loss due to the use of the frequency domain is very high, so it may be difficult to provide a service compared to the existing 4G LTE system. To overcome these shortcomings, various techniques are under study. In this paper, small cell technology is introduced to improve the system performance of 5G mobile communication systems. The performance is analyzed by comparing the results of small cell technology application, macro communication and small cell communication, and the results of the proposed algorithm application for power control. The analysis results show that the use of small cell technology in the 5th generation mobile communication system can significantly reduce the shadow area and reduce the millimeter wave path loss problem.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.124-130
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• 2007

In the present study, I investigated the effects of N-methyl-D-aspartate (NMDA), arachidonic acid (AA), and Nitric Oxide Synthase Inhibitor (NOSI), alone or in combination, on the proliferation of cultured primary normal human oral keratinocytes (NHOK). The purpose of this study was therefore the preliminary study for the examination of the interaction between these agents and NHOK in order to elucidate the mechanisms by which epithelial growth and regeneration are regulated. NHOK were obtained from gingival tissue of 20 individuals aged 20 to 29, and third passage (P3) cells were used for this study. The DNA synthesis was measured by the BrdU assay. Addition of low concentration of AA ($1{\mu}M$) and high concentration of AA with NMDA group (NMDA+AA $10{\mu}M$) made DNA synthesis rate increase significantly at the early stage. Adding NNA ($10{\mu}M$) affected DNA synthesis rate to increase significantly in 4 hours. At the early stage, DNA synthesis was significantly active in the NOS-I with NMDA groups than in the control and the NMDA-only group, while it didn't become statistically meaningful in 24 hours. AA $1{\mu}M$ and NNA $10{\mu}M$ may induce the proliferation of the NHOK independently and NOS-I may induce the proliferation of the NHOK with NMDA. These reactions might be related to the NMDA receptor in the cell and the change of the intracellular calcium ion concentration.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.759-769
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• 2015

Diode rectifiers are very popular in industry. However, they include large low-order harmonics in the input current and do not satisfy harmonic current content restrictions. To reduce the harmonics to the power system, several methods have been introduced. It is heavy and expensive solution to use passive filters as the solution for high power application. Another solution for the harmonic filter is utilization of active filter, but it is too expensive solution. Diode rectifiers with configurations using switching device have been introduced, but they are very complicated. The combined 12-pulse diode rectifier with the square auxiliary voltage supply has been introduced. It has the advantages that auxiliary circuit is simple and inexpensive compared to other strategies. The advanced auxiliary voltage supply in this thesis is presented as a new solution. When the square auxiliary voltage supply applied, the improvement of THD is 6~60[%] in whole load range. But when the advanced auxiliary voltage supply applied, it shows stable and excellent reduction effect of THD as 57~71[%]. Especially, for the case with 10[%] load factor, reduction effect of THD has little effect as 6[%] in the case of inserting a square auxiliary voltage supply. But when the proposed new solution applied, reduction effect has excellent effect as 71[%]. Theoretical analysis of the combined 12-pulse diode rectifier with the advanced auxiliary voltage supply is presented and control methods of the auxiliary supply is proposed. The reduction in the input current harmonics is verified by simulation using software PSIM.

• 한국균학회소식:학술대회논문집
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• 2015.11a
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• pp.41-41
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• 2015

Oomycetes belong to the kingdom Straminipila, a remarkably diverse group which includes brown algae and planktonic diatoms, although they have previously been classified under the kingdom Fungi. These organisms have evolved both saprophytic and pathogenic lifestyles, and more than 60% of the known species are pathogens on plants, the majority of which are classified into the order Peronosporales (includes downy mildews, Phytophthora, and Pythium). Recent phylogenetic investigations based on DNA sequences have revealed that the diversity of oomycetes has been largely underestimated. Although morphology is the most valuable criterion for their identification and diversity, morphological species identification is time-consuming and in some groups very difficult, especially for non-taxonomists. DNA barcoding is a fast and reliable tool for identification of species, enabling us to unravel the diversity and distribution of oomycetes. Accurate species determination of plant pathogens is a prerequisite for their control and quarantine, and further for assessing their potential threat to crops. The mitochondrial cox2 gene has been widely used for identification, taxonomy and phylogeny of various oomycete groups. However, recently the cox1 gene was proposed as a DNA barcode marker instead, together with ITS rDNA. To determine which out of cox1 or cox2 is best suited as universal oomycete barcode, we compared these two genes in terms of (1) PCR efficiency for 31 representative genera, as well as for historic herbarium specimens, and (2) in terms of sequence polymorphism, intra- and interspecific divergence. The primer sets for cox2 successfully amplified all oomycete genera tested, while cox1 failed to amplify three genera. In addition, cox2 exhibited higher PCR efficiency for historic herbarium specimens, providing easier access to barcoding type material. In addition, cox2 yielded higher species identification success, with higher interspecific and lower intraspecific divergences than cox1. Therefore, cox2 is suggested as a partner DNA barcode along with ITS rDNA instead of cox1. Including the two barcoding markers, ITS rDNA and cox2 mtDNA, the multi-locus phylogenetic analyses were performed to resolve two complex clades, Bremia lactucae (lettuce downy mildew) and Peronospora effuse (spinach downy mildew) at the species level and to infer evolutionary relationships within them. The approaches discriminated all currently accepted species and revealed several previously unrecognized lineages, which are specific to a host genus or species. The sequence polymorphisms were useful to develop a real-time quantitative PCR (qPCR) assay for detection of airborne inoculum of B. lactucae and P. effusa. Specificity tests revealed that the qPCR assay is specific for detection of each species. This assay is sensitive, enabling detection of very low levels of inoculum that may be present in the field. Early detection of the pathogen, coupled with knowledge of other factors that favor downy mildew outbreaks, may enable disease forecasting for judicious timing of fungicide applications.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.395-405
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• 2014

This study tends to grasp the physical activity on its influences and effect s to the mental health of middle school students and we tried to look for a specific plan that will help to improve middle school students' mental health. We analyzed 36,530 students in middle school using a basic data "9th (2013) health behavior of juvenile on the online". The study is analyzed by complex sample data analysis method. The degree of euphoria recognition showed the low feeling of happiness when students exercise directly below two times rather than three times a week in the Physical Education class at school. On the other hand, the possibility of stress perception degree and suicide attempt is lowered. If the number of sports team participating is below one team, euphoria would be lowered and the limit of stress perception is high. However, the participation of one or two teams make the possibility of suicide lessens rather than students taking part in more 4 teams. In order to help middle school students reduce their stress and improve their happiness, they need to participate in sports as a regular team and join intramural games more than three times a week. In this case of the lower grade, it is considered that it is necessary for them to combine the educational program for the emotional support to control their extreme behavior.

• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.75-82
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• 2016

The technology of fast pyrolysis is regarded as a promising route to convert lignocellulose biomass into bio-oil which can be upgraded to transportable fuels and high quality chemical products. Despite these promises, commercialization of bio-oil for fuels and chemicals production is limited due to its notoriously undesirable characteristics, such as high and changing viscosity, high water and oxygen contents, low heating value and high acidity. Therefore, in this study quality improvement of bio-oil through vaccum distillation had been targeted. A 600 g of cork oak(Quercus variabilis) which grounded 0.8~1.4 mm was processed into bio-oil via fast pyrolysis for 1.64 seconds at $465^{\circ}C$ and temperature of vaccum distillation(100hPa) was designed to control, $40^{\circ}C$, 50, 60, 70, and 80 for 30min. Bio-oil, biochar, and gas of pyrolytic product were produced to 62.6, 18.0 and 19.3 wt%, respectively. The water content, viscosity, HHV(Higher Heating Value) and pH of bio-oil were measured to 0.9~26.1 wt%, 4.2~11.0 cSt 3,893~5,230 kcal/kg and 2.6~3.0, respectively. Despite these quality improvement, production was still limited due to its notoriously undesirable characteristics, therefore continous quality improvement will be needed in order to use practical fuel of bio-oil.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2003.10a
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• pp.105-126
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• 2003

In Korea most of annual rainfall is concentrated in several episodic heavy rains during the season of summer monsoon and typhoon. Because of uneven rainfall distribution many dams have been constructed in order to secure water supply in dry seasons. The Han River system has the most dams among Korean rivers, and the river is a series of dams now. Reservoirs need different strategy of water quality control from river water. Autochthonous organic matter and phosphorus should be the major target to be controlled in lakes. In this Paper some problems are discussed that makes efforts of water quality improvement ineffective in lakes of Korea, even after the substantial investment to wastewater treatment facilities.1) Phosphorus is the key factor controlling eutrophication of lakes and the reduction ofphosphors should be the major target of water treatment. However, water quality management strategy in Korea is still stream-oriented, and focused on BOD removal from sewage. Phosphorus removal efficiency remains as low as 10-30%, because biological treatment is adopted for both secondary treatment and advanced treatment. The standard for TP concentration of the sewage treatment plant effluent is 6 mgP/l in most of regions, and 2 mg/l in enforced region near metropolitan water intake point. TP in the effluents of sewage treatment plants are usually 1-2 mg/1, and most of plants meet the effluent regulation without a further phosphorus removal process. The generous TP standard for effluents discourages further efforts to improve phosphorus removal efficiency of sewage treatment. Considering that TP standard for the effluent is below 0.1 mg/l in some countries, it should be amended to below 0.1 mg/l in Korea, especially in the watershed of large lakes.2) Urban runoff and combined sewer overflow are not treated, even though their total loading into lakes can be comparable to municipal sewage discharges on dry days. Chemical coagulation and rapid settling might be the solution to urban runoff in regard of intermittent operation on only rainy days.3) Aggregated precipitation in Korea that is concentrated on several episodic heavyrains per year causes a large amount of nonpoint source pollution loading into lakes. It makes the treatment of nonpoint source discharge by methods of other countries of even rain pattern, such as retention pond or artificial wetland, impractical in Korea.4) The application rate of fertilizers in Korea is ten times as high as the average ofOECD countries. The total manure discharge from animal farming is thought to be over the capacity of soil treatment in Korea. Even though large portion of manure is composted for organic fertilizer, a lot of nutrients and organic matter emanates from organic compost. The reduction of application rate and discharge rate of phosphorus from agricultural fields should be encouraged by incentives and regulations.5) There is a lot of vegetable fields with high slopes in the upstream region of the HanRiver. Soil erosion is severe due to high slopes, and fertilizer is discharged in the form of adsorbed phosphorus on clay surface. The reduction of soil erosion in the upland area should be the major preventive policy for eutrophication. Uplands of high slope must be recovered to forest, and eroded gullies should be reformed into grass-buffered natural streams which are wider and resistant to bank erosion.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.3
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• pp.1-14
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• 2010

Areas with negative images in cities can degrade the image of the city as a whole and slow the city's efforts to improve its image. The identification of such areas and the development of a city contour that charts the images of various areas in advance can help urban planners establish relevant strategies to ameliorate detrimental images of the city. This study intends to draw a contour of Seongnam City according to citizen's cognition levels of and preference for city area images and aim to shift the strategy of urban image planning from being results-oriented to being process-oriented. The results of this study are as follows: First, an analysis of the level of cognition of and preferences for Seongnam City's landmarks shows that the degree of cognition varies in different areas, whereas that of preferences remains similar; Second, the cognition and preference contour makes it easy to assess and diagnose city images; Third, the image management map, which merges the cognition contour with the preference contour, divides the city into four different areas. In order to manage city images, it follows that those areas with a high degree of cognition but low preference need to be classified and dealt with first. Further, this study shows that those areas with high cognition are the most populated and visited. Areas with high preference can become a strong candidate for being a landscape control point of a city, which adds to the usefulness of this study. The contour of Seongnam will contribute to networking sightseeing areas for visitors centered upon those places of high preference. It would appear that this type of networking will inspire a better image for the city.

• Journal of the Korean Dietetic Association
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• v.5 no.2
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• pp.153-163
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• 1999

The purpose of this study was to obtain basic data of nutrition education for obese children and to examine food habits, food behaviors, and nutrition knowledge. A convenience sample of 84(male:62, female:22) obese children was selected from "98 Children Nutrition Camp". The survey design employed a structured questionnaire. The results of this study were summarized as follows. 1. The percentage of the subjects who overestimated their body weight was higher in female compared to male. Only 35.9% of highly-obese subjects considered them as 'very fat'. The experience of weight control was higher in female than in male, and it was also higher moderately- or highly-obese subjects compared to mildly obese. 2. 64.3% of subjects reported that they regularly eat breakfast. The percentage of the subjects who indicated that they eat at regular meal time or they eat very irregularly was highest in the highly-obese subjects. 3. 34.5% of subjects reported that they eat very fast. The eating speed was slower in female compared to male, and in obese subjects. 55.4% of subjects reported that didn't eating out. 4. 80.9% of subjects had snacks, and most of them had snack between lunch and dinner. The reason the subjects eat snack was hunger. The most favorite snack was cookies. 5. The most preferred and distasteful food was meats(32.1%) and vegetables(67.1%), respectively. 6. The score of food behaviors was relatively low in most subjects. 7. The level of nutrition knowledge was in order of fair(83.1%), poor(9.6%), excellent(7.3%), and was higher in male compared to female. Consequently the results of this study showed to disagreement among food habits, food behaviors and nutrition knowledge, and feel keenly the necessity of education connecting of these. This education had to be practical education to change food behaviors.