• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.5
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• pp.442-448
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• 1992

In order to determine the critical seeding date in dry paddy field at southern plain area of Gyeongbug province, dry seeds of three different rice cultivars was sown April 25 to June 20 at 15 or 10-day intervals. The number of days from seeding to emergence decreased in late seeding date : from 32 days at April 25 to 7 days at June 10 sowing. The number of seedlings showed 121-154 plants per square meter were not much differed among the varieties and seeding dates. Culm length, panicle length and ripened grain ratio decreased in late seeding date, but number of panicles per square meter, 1,000 grain weight and spikelets number per panicle were similar among the seeding dates. The cumulative effective temperature(mean air temperature-15$^{\circ}C$) from emergence to heading was very constant having 655$\pm$9$^{\circ}C$ in Keomhobyeo, 771$\pm$9$^{\circ}C$ in Donghaebyeo and 801$\pm$3$^{\circ}C$ in Milyang 95, respectively. Grain yield of Dong Haebyeo seeded in June 20 and Milyang 95 seeded in June 10 were much lower compared with other seeding dates and increased green kernel in late seeding date of Donghaebyeo and Milyang 95.

• The Journal of Engineering Geology
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• v.20 no.4
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• pp.449-459
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• 2010

We performed numerical simulations of the excavation of an underground structure (the Giheung Tunnel) in order to evaluate the rate of groundwater flow into the structure and to estimate the groundwater level around the structure. The tunnel was constructed in Precambrian bedrock in Gyeonggi Province, South Korea. Geological and electrical resistivity data, as well as hydraulic test data, were used for the numerical modeling. The modeling took into account the strike-slip faults that cross the southern part of Giheung Tunnel, as these structures influence the discharge of groundwater into the tunnel. The transient modeling estimated a groundwater flow rate into the tunnel of $306\;m^3$/day, with a grout efficiency of 40%, yielding good agreement between the calculated change in groundwater level (6.20 m) and that observed (6.30 m) due to tunnel excavation.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.5
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• pp.353-361
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• 2015

The area of red tides occurences, which brings enormous damages every year, have been expanded to the coastal waters across the nation. Regarding to this trend, the development of red tide detection technology by using the GOCI (Geostationary Ocean Color Imager) of COMS lauched in 2010 has been drawn attentions of researchers. This study purposed on analyzing the frequency and density of red tides occurence by using the GOCI for detecting the southern sea, whereas targeted area. The observation has brought over the last three years (2012, 2013, and 2014) before the analysis was conducted. Followingly, the study could be resulted in extracting and revealing the hot spots of the red tides from two of analysis in the overlay and density. The distribution patterns of red tide occurrences according to those observed years has been shown in irregular characteristics and various changes. However, the analysis of hot spots, based on the frequency of the red tide occurrence, has revealed that the frequency of red tide occurences is continuously increased in the specific sea area. Therefore, it is concluded in that the continuous monitoring can contribute to predict accurate movements of red tides, so as establish systematic plans for preventing disasters.

• The Journal of the Korea Contents Association
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• v.16 no.10
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• pp.226-234
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• 2016

This study aimed to research the effects of emotional labor of contingent workers in foodservice industry on job burnout, job satisfaction and turnover intention, and to achieve the purpose that it was needed to analyze the factors of emotional labor to research the effect of emotional labor on job burnout, and to research the effect of job burnout on job satisfaction and turnover intention. Data were collected from foodservice restaurants located in southern Gyeonggi province by face-to-face interview. The questionnaire was distributed of the 300 copies and used 271 in the analysis. The results are as followed; First, the factors of emotional labor were surface acting and deep acting. Second, surface acting had positive significant influence on job burnout. Third, deep acting had negative significant influence on job burnout. Four, job burnout had negative significant influence on job satisfaction and job burnout had positive significant influence on turnover intention. This research requires many studies about deep acting of contingent workers in foodservice industry.

• Korean Journal of Weed Science
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• v.18 no.4
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• pp.356-363
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• 1998

In general weed vegetation analysis has been applied to the study of weed population shift. However, it is a limited tool for understanding a problem region and a specific weed species in a certain area. Recently GIS may be used as an important tool to solve this target or to conduct specific field analysis which enables to introduce a reasonable management strategy. Thus, the GIS study was carried out to understand an integrated weed population changes between 1981 and 1992 in Korea. The nationwide weed survey was performed through the whole rice paddy fields in 1981 and 1992. Weed occurrence was totally different over whole country based on these data. In 1981 a region with high weed occurrence was at western and central areas of Korea in terms of weed population density but this was changed into western and southern area in 1992. In both years there were high weed population density at Taean, Seosan county of Chungnam province in Korea. Thus, this particular area may be needed to introduce a special strategy to reduce weed population density and/or to control problem weed species.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.4
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• pp.389-395
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• 1996

This survey was conducted to investigate the factors affecting the chemical components of groundwater in the plastic house area cultivated with horticulture crops. The data were evaluated with depth of groundwater, topography and years of cultivation as major factors. $NO_3-N$ content of groundwater was higher at waterside(Alluvial plain) than Inland plain(Alluvial plain), local valley & fan or mountain foot area, and also was detected the highest concentration in 6-10m depth well. The contents of $NO_3-N$ and $SO_4{^{2-}}$ in groundwater were increased with cultivation years. The ionic composition (${\sum}A/{\sum}C$ : ratio between total equivalant of anions and cations) of groundwater decreased with depth and was higher at waterside(alluvial plain) than other topography. The $NO_3-N$ content was negatively correlated with pH whereas it was positively correlated with $SO_4{^{2-}}$, $Cl^-$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$.

• Korean Journal of Plant Resources
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• v.26 no.1
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• pp.90-102
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• 2013

This study was carried out in order to catalogue the folk plants of 5 counties and cities of Chungcheongbuk-do Province from March to October, 2011. 429 pages of field notes relating to the folk plants were collected from approximately 92 local inhabitants and analyzed subsequently. The identified folk plants were of 173 taxa, composed of 150 species, 1 subspecies, 22 varieties and 129 genera under 56 families. Naturalized plants were included. The use by its usage was: 349 taxa; edible, 68 taxa; medicinal, 2 taxa; dye, 1 taxa; aroma, 4 taxa; spice, 1, taxa; ornamental, 3 taxa; oil, 1 taxa; starch, 18 taxa; others respectively, so the edible use is the highest. The most useful part was the leaf, followed by stem, and whole plant. The consistency comparison between the scientific name and the local name were the highest in the 50's and the lowest in 90's.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.3
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• pp.208-214
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• 2016

This study was conducted to evaluate the effects of different sowing times (May 25, June 10, June 25, July 10, and July 25) on growth and yield of four proso millet (Panicum miliaceum L.) cultivars (Hwanggeumkijang, Manghongchal, Ibaekchal, and Hwangsilchal) at a cultivation area in Iksan, Jeonbuk Province. Heading and ripening times were delayed, with later sowing times in all cultivars, and the periods for heading and ripening were shortened. For sowing from May 25 to July 25, the growth stage was shorter by 40 days in Manghongchal, 38 days in Hwanggeumkijang, 36 days in Hwangsilchal, and 30 days in Ibaekchal. The culm length, ear length, ear width, and culm diameter differed significantly between the cultivars and sowing times. In particular, the culm and ear lengths were considerably reduced when the sowing time was delayed. The grain yield (kg/10a) of Hwanggeumkijang and Ibaekchal was 312 and 359 kg, respectively, for sowing on June 10; and that of Manhongchal and Hwangsilchal was 286 and 404 kg, respectively, for sowing on June 25. Thus, the optimum sowing time was June 25 for Hwanggeumkijang and Ibaekchal, and June 10 for Manhongchal and Hwangsilchal.

• Journal of Korean Society of Forest Science
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• v.98 no.2
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• pp.183-188
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• 2009

It is necessary to determine the amount of carbon dioxide ($CO_2$) absorbed by plants and released from forest floor into atmosphere, to gain a better understanding how forests participate in the global carbon cycle. Soil $CO_2$ efflux, litter production, and decomposition were investigated in Q. variabilis and P. densiflora stands in the vicinity of Gwangju, Chonnam province. Soil $CO_2$ efflux was measured using Infrared Gas Analyzer (IRGA) at midday of the 10th day at every month over 12-month period, to quantify seasonal and annual budgets of soil $CO_2$ efflux. Soil temperature and soil moisture were measured at the same time. Seasonal soil $CO_2$ efflux in Q. variabilis and P. densiflora were the highest in summer season. In August, maximum soil $CO_2$ efflux in Q. variabilis and P. densiflora was 7.49, $4.61CO_2{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. Annual $CO_2$ efflux in each stand was 1.77, $1.67CO_2kg{\cdot}m^{-2}$ respectively. Soil $CO_2$ efflux increased exponentially with soil temperature and related strongly in Q. variabilis ($r^2$=0.96), and in P. densiflora ($r^2$=0.91). Litter production continued throughout the year, but showed a peak on November and December. Annual litter production in the Q. variabilis and P. densiflora stands were $613.7gdw{\cdot}m^{-2}{\cdot}yr^{-1}$ and $550.5gdw{\cdot}m^{-2}{\cdot}yr^{-1}$.$yr^{-1}$, respectively. After 1 year, % remaining mass of Q. variabilis and P. densiflora litter was 48.2, 57.1%, respectively. The soil $CO_2$ efflux rates in this study showed clear seasonal variations. In addition, the temporal variation in the $CO_2$ efflux rates was closely related to the soil temperature fluctuation rather than to variations in the soil moisture content. The range of fluctuation of soil $CO_2$ efflux and litter decomposition rate showed similar seasonal changes. The range of fluctuation of soil $CO_2$ efflux and litter decomposition rate was higher during summer and autumn than spring and winter.

• Journal of Wetlands Research
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• v.6 no.1
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• pp.149-166
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• 2004

Water quality and ecological environment in the Han River estuary was analyzed using the longterm water quality monitoring data from National Fisheries Research and Development Institute (NFRDI) and the existing data collected in this area. Based on the salinity distribution and changes of current direction in the lower Han River and its estuary, boundaries of the estuary were identified and also, distribution patterns of the phyto- and zooplankton, benthos, ichthyoplankton and fish were discussed related with the salinity changes in the macrotidal subestuary of Han River. Seasonal and spatial distribution of salinity suggested that the direct impact of freshwater be limited to the Incheon North Harbour all the year round and even extended to the southern area of Gyunggi Bay near Palmi island during limited time, usually in summer. Upper limit of salt water intrusion through the Han River is likely to be Singok underwater dam located Gimpo, Gyunggi Province, and normally limited to much lower part of the river, Jeonryuri, Gimpo. Biological boundaries of the Han River estuary exceeded the physical boundaries based on the salinity distribution. Many estuarine species in plankton and fish were found at the totally freshwater or saltwater depending on the seasons and tidal cycles. Some estuarine ichthyoplanktons showed extremely limited distributions in the estuary whereas adult fish revealed wide ranges of salinity adaptation. Critical environmental issues in the Han River estuary and its drainage basin are likely to be 1) pressure on development-promoted district for new town in the drainage area of the estuary, 2) reduction of tidal flat by reclamation, 3) pollutant input through river from municipal sewages and industrial wastes, and 4) ecological barrier between river and terrestrial systems by the military wire fence and riverside road.