• Journal of Environmental Impact Assessment
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• v.26 no.6
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• pp.553-562
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• 2017

In these days, agricultural reservoirs are considered as a useful resource for recreational purposes, tour and cultural amenity for vicinity communities as well as irrigation water supply. However, many of the agricultural reservoirs are showing a eutrophic or hyper-eutrophic state and high level of organic contamination. In particular, about 44.7% of the aged agricultural reservoirs that constructed before 1945 exceed the water quality criteria for irrigational water use. In addition to external loading, internal nutrient loading from bottom sediment may play an important role in the nutrient budget of the aged reservoirs. The objectives of this study were to characterize variations of thermal structure of a shallow M reservoir (mean depth 1.7 m) and examine the potential of internal nutrient loading by continuous monitoring of vertical water temperature and dissolved oxygen (DO) concentration profiles in 2015 and 2016. The effect of internal loading on the total loading of the reservoir was evaluated by mass balance analysis. Results showed that a weak thermal stratification and a strong DO stratification were developed in the shallow M Reservoir. And, dynamic temporal variation in DO was observed at the bottom of the reservoir. Persistent hypoxic conditions (DO concentrations less than 2 mg/L) were established for 87 days and 98 days in 2015 and 2016, respectively, during the no-rainy summer periods. The DO concentrations intermittently increased during several events of atmospheric temperature drop and rainfall. According to the mass balance analysis, the amount of internal $PO_4-P$ loading from sediment to the overlying water were 37.9% and 39.7% of total loading during no-rainy season in 2015 and 2016, respectively on August when algae growth is enhanced with increasing water temperature. Consequently, supply of DO to the lower layer of the reservoir could be effective countermeasure to reduce nutrient release under the condition of persistent DO depletion in the bottom of the reservoir.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.4
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• pp.29-41
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• 2015

Abandoned paddy field provides an excellent opportunity to improve the species diversity and habitat quality. Ecological characteristic on the changing of plant communities at different seral stages is a major basis data for ecological restoration. In this study, we investigated changes of the species composition and community indices on the plant community associated with abandonment of cultivated rice paddies. The ecological stability of the habitat was evaluated by using eco-floristic characters(Di; Disturbance index, AUI; Actual urbanization index). Survey sites were grouped into six stages(stageI (${\leq}3years$), stageII(3-5years), stageIII(5-7years), stageIV(7-10years), stageV(10-15years), stageVI(${\geq}20years$). Vegetation investigation was done from May 2009 to October 2012 and carried out phytosociological approach. The total flora were summarized as 176 taxa including 58 families, 127 genera, 157 species, 3 subspecies, 15 varieties and 1 forms. At each of successional stages, 64 taxa in stage I, 34 taxa in stage II, 84 taxa in stage III, 83 taxa in stage IV, 92 taxa in stage V, 23 taxa in stage VI were identified. Of the occurrence plants, the species with the highest r-NCD value were Alopecurus aequalis, Juncus effuusus var. decipiens, Persicaria thunbergii, Artemisia princeps, Salix koreensis and Alnus japonica at each stages. Herbaceous annual plants were dominated in the early stage, but its r-NCD value declined in the middle stage and the late stage. On the other hand, herbaceous perennial plants and Persicaria thunbergii, annual hydrophytes, increases in the middle stage. Woody plant and herbaceous plant which appeared in the forest edge increases in the late stage. Community indices correlate with successional stages. Richness and diversity index increase along the successional gradient. But dominance index decrease along the successional gradient. Evenness index was correlated with lower. In the ecological stability analysis of the habitat that evaluated by eco-floristic characters, stage I was the most unstable habitat. And the stability of the habitat has improved according to the successional stage.

• Journal of Food Hygiene and Safety
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• v.13 no.2
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• pp.77-82
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• 1998

As a fundermental research for quality stailization of herb extract, the effects of water activity on microbial growth in herb extract were investigated. Herbs-Panax ginseng, Cinnamomum cassia, Lycium chinense, Zyzyphus jujuba, Lindera obtusilobum-were mixed and extracted with water at $80^{\circ}C$ and concentrated at $75^{\circ}C$. Water activity of the herb extract was adjusted to 0.86, 0.80 and 0.69, using water activity analyzer. The extracts were incubated for 180 days at $40^{\circ}C$ and then examined microbial cell counts and some physicochemical properties. In the extract of $a_{w}$ 0.86, 18 CFU/g of initial viable cell was increased to 80 CFU/g with 90 days of incubation and to 190 CFU/g 180 days of incubation. In the extract of $a_{w}$ 0.80, 24 CFU/g of initial viable cell was also increased to 83 CFU/g during the 90 days of incubation and to 170 CFU/ g for the 180 days of incubation. However, in the extract of $a_{w}$ 0.69, viable cell after 180 days of incubation was remained at almost the same level as initial viable cell. pH of herb extract was reduced in proportion to the decrease in water activity. The TLC (thin layer chromatography) patterns of ginseng saponins of herb extract did not show any significant changes after 180 days of incubation. Growth of pathogenic microorganisms was inhibited more with lower water activity of the herb extracts. In the herb extract inoculated with Candida albicans and Aspergillus niger, initial viable cells of 150 and 140 CFU/g were decreased to 30 and 20 CFU/g, repectively, after 30 days of incubation at $28^{\circ}C$. In the case of herb extract inoculated with Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, growth of the bacteria was totally inhibited even after 30 days of incubation at $37^{\circ}C$.

• Korean Journal of Ecology and Environment
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• v.41 no.spc
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• pp.50-60
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• 2008

We performed the experiment to evaluate the effect of different DO concentrations (0.5, 4.5 and 9.0 $mgO_2L^{-1}$) and water depths (20, 50 and 80 cm) on the filtering rate, mortality, and pseudifeces production of Unio douglasiae against the cyanobacterial bloom (mainly Microcystis aeruginosa). A solitary-living bivalve U. douglasiae was collected in the upstream region of the North Han River (Korea). The harvested mussels were carefully transferred to the laboratory artificial management system, which was controlled temperature $(18{\pm}2^{\circ}C)$, flow rate (10L $h^{-1}$), food $(Chlorella^{TM})$, sediment (pebble and clay), light intensity (ca. $20{\mu}mol$ photons), and photocycle (12 L : 12 D). In the field observation, the mussel mortality was significantly correlated with water temperature, pH and DO concentration (P<0.05). The mortality was decreased with water depth; 65, 90, 80% of mortality at 20, 50, 80 cm water-depth, respectively. Filtering rate (FR) showed the highest value at 50 cm water depth, and thereby the concentration of chlorophyll-${\alpha}$ decreased continuously by 94% of the control at the end of the experiment. In contrast, FR decreased by 34% of the initial concentration at 20 cm water depth. Over the given water-depth range, the mussel FR ranged from $0.15{\sim}0.20L\;gAFDW^{-1}hr^{-1}$ during the 18hrs of experiment, and thereafter, they appeared to be approximately 0.11, 0.26 and 0.30 L $gAFDW^{-1}hr^{-1}$ at 20, 50 and 80cm water depth, respectively. FR was highest with the value of 0.46L $gAFDW^{-1}hr^{-1}\;at\;0.5mgO_2 L^{-1}$ at the early stage of the experiment, while it increased with DO concentration. Maximum pseudofaeces production was 11.2 mg $gAFDW^{-1}hr^{-1}\;at\;9.0mgO_2L^{-1}$. Our results conclude that U. douglasiae has a potential to enhance water quality in eutrophic lake by removing dominant cyanobacteria, but their effects vary with environmental parameters and the water depth at which they are located.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.4
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• pp.347-358
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• 2004

In Mongolia which consists of nomadic populations, horse has been loved by nomads and considered most important transportation means. Horses have been used when they were making long journey looking for new plain ground for grazing. Therefore, horse is closely connected with Mongolian nomadic culture. In Korea, too, horses had been considered one of most important means for transportation and military. The symbolism of horse that is represented in both Mongolia and Korea is Heavenly Horse which communicates with the God and it was sanctified as a Sacrificing Horse which was sent to God for sacrifice, and it was even worshiped as Divine Horse, the diety. As is the case of two of Mongolian customs associated with Mongolian language are 'the ceremony of horse's giving birth her young' and 'the ceremony of letting the mare go where it was before', all the cases are related with cattle's milk. The ceremony of 'horse's giving birth her young' is the ceremony where people hope that they would see the young can grow well which were born in early summer thus increasing the numbers of horse. To go with this, they perform a ceremony of Chachal in which they sprinkle the best quality white milk which is the symbol of good luck and hope they would produce plentiful of dairy products. The ceremony of 'letting the mare go where it was before' is also the ceremony where people hope to have many new born young horses thus produce more dairy products and Airag for the next year as milking is no more available for that you. Since the unified Silla Era, Koreans have performed a sacrifice rituals to horse in auspicious day. It's purpose is to see their horses get no disease and bear as many youngs as possible. The Back Ins Je, one of well blown festivals in Jeju Island, was originated from people's wish to prosper in stock farming. It can be said that the custom of Korea and Mongolia related with horse's giving birth was originated from the wishes to god for fertility and fecundity. On top of that, while Mongolians sprinkled horse's milk both on the ground and to the air hoping they would have increased houses and, thus, secure many dairy products, Koreans wish that they would see the increased number of horses and their healthy conditions through heavenly rituals.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.4
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• pp.307-312
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• 2009

This experiment was conducted to compare the agronomic characteristics and productivity of induced annual legumes at paddy field of Cheonan and Naju from 2004 to 2006. Chinese milk vetch (wild type), crimson clover (C.V. Linkarus), forage pea (C.V. Austrian pea), hairy vetch (C.V. Oregon commen) were used in this study. At the Naju region, the earliest flowering on 2nd may was found in Chinese milk vetch, while the latest on 18th May in forage pea. Fresh, dry matter (DM) and crude protein (CP) yields of crimson clover were highest as 28,870, 6,986 and 943 kg/ha, respectively. but the yield of chinese milk vetch was low by 9,885, 1,749 and 338 kg/ha. At the Cheonan region, the most fast flowering date variety was Chinese milk vetch, hairy vetch was very late as 19th May. Fresh, DM and CP yields of hairy vetch were highest as 7,916, 1,141 and 113 kg/ha, respectively. but the yield of chinese milk vetch showed the lowest by 270, 42 and 8 kg/ha. The CP content of annual legumes was 14.3%. chinese milk vetch showed the highest CP content by 19.3% and hairy vetch showed the lowest content by 9.9%. The present data showed that the productivity was closely dependent on winter hardness, in conclusion, crimson clover at Naju and hairy vetch at Cheonan region was suggested to be the most proper species as winter crop after rice harvest on paddy field when considered the winter hardiness.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.1
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• pp.7-12
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• 2009

This experiment was conducted to compare the agronomic characteristics and productivity in introduced forage pea cultivars at the experimental field. The experiment was arranged in a randomized block design with three replications. The forage pea used in this study were two cultivars ('Livioletta', 'Austrian Pea') and one Chinese milk vetch cultivar (Chinese domestic cultivar). Flowing of 'Livioletta' cultivar was May 16th and 'Austrian Pea' cultivar was 18th May, 20 days later than the former. The 'Livioletta' cultlvar showed stronger than winter hardiness of 'Austrian Pea' cultivar. Dry matter (DM) content of 'Liviotetta' and 'Austrian Pea' cultivars were 22.5% and 20.9% chinese milk vetch showed the lowest content with 17.7%. 'Austrian pea' cultivar showed the highest DM yield with 5,617 kg/ha but the DM yield of 'Livioletta' cultivar was low with 3,652 kg/ha. The yield of CP (crude protein) and TDN (total digestible nutrient) set high at 'Austrian Pea' cultivar. And 'Livioletta' and 'Austrian Pea' cultivars showed CP content with 15.5% and 14.4% but Chinese milk vetch with 19.3%. The acid detergent fiber (ADF) and neutral detergent fiber (NDF) content of 'Austrian Pea' cultivar were 23.2% and 40.3%. Therefore 'Austrian pea' cultivar seems to be suitable varieties in paddy field as winter forage crops.

• Journal of Animal Science and Technology
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• v.53 no.4
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• pp.283-288
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• 2011

This study was conducted to study the environment effects on live weight, carcass weight, dressing percentage, eye muscle area, backfat thickness, and marbling score, which are the carcass traits of Hanwoo, based on the estimates and all the possible regression for the selection of variable and significance test for 231,382 heads that underwent the carcass measurements. The average and standard deviation for the live weight, carcass weight, dressing percentage, eye muscle area, backfat thickness, and marbling score were 654.79${\pm}$91.61 kg, 362.30${\pm}$67.15 kg, 59.52${\pm}$0.03%, 81.79${\pm}$12.21 $cm^2$, 11.39${\pm}$5.40 mm, 4.38${\pm}$2.29, respectively. The live weight, carcass weight, dressing percentage, eye muscle area, backfat thickness, and marbling score for cow were 532.79${\pm}$78.38 kg, 313.40${\pm}$44.90 kg, 56.50${\pm}$0.03%, 75.24${\pm}$10.69 $cm^2$, 11.82${\pm}$5.10 mm, 4.30${\pm}$2.06, respectively, while for bull were 619.74${\pm}$93.27 kg, 376.89${\pm}$48.62 kg, 58.61${\pm}$0.02%, 85.61${\pm}$10.46 $cm^2$, 5.64${\pm}$2.71 mm, 1.41${\pm}$0.83, respectively, and for steer were 681.78${\pm}$70.72 kg, 415.23${\pm}$49.43 kg, 60.19${\pm}$0.02%, 88.29${\pm}$10.27 $cm^2$, 12.71${\pm}$5.23 mm, 5.42${\pm}$1.99, respectively. In the environmental variables selection based on the variables selection method, the examination by carcass traits suggested that the most appropriate model could be determined when five variables were selected for the live weight, carcass weight, dressing percentage, eye muscle area, and four variables for backfat thickness, and marbling score. When they were considered at a time altogether based on multiple traits, it was deemed to be desirable to insert all five variables into the variables for analysis. In addition, high significance was found by carcass traits.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.2
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• pp.177-190
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• 2011

This study was conducted to determine effects of dietary herbaceous peat on in vitro fermentation and milk production in dairy cows. Ruminal pH, gas production, VFA (volatile fatty acid), Ammonia-N, and rumen degradability were examined by the addition of three times over 0, 1, and 5% herbaceous peat with substrate of timothy hay, and the change of rumen fermentation characteristics were evaluated. In 0, 3, 12 and 24 hours cultivation, all treatments did not show a significant difference but the control at 6 hours appeared significantly lower pH compared to 1 and 5% treatments (p<0.05). The gas production of the treatments significantly increased until 12 hours of cultivation compared to control (p<0.05), the rumen ammonia concentration showed a tendency to increase until 24 hours in all treatment groups, and there was no significant difference between treatments. About the rumen degradability, 5% treatment showed higher rumen degradability in all hours than control and 1% treatment (p<0.05). Meanwhile, for in vivo trial, 16 heads of Holstein lactation dairy cows were selected for experiment for four weeks in order to research the change of milk yield, milk compositions and change of somatic cell counts of lactation dairy cows by herbaceous peat feeding. The milk yield of vitamin C and herbaceous peat treatments (T3) was 25.0 kg but the control was 23.2 kg, herbaceous peat treatment (T1) was 23.1 kg, and vitamin C treatment (T2) was 23.4 kg, so there was linear increase effect of milk yield by T3. The partial significance of the milk (fat, milk protein, lactose, MUN and SNF) and change of somatic cell count before and after experiment by the control and treatments about change of milk and somatic cell counts (p<0.05) were recognized. About change of milk in the first half (1~2 weeks) and latter half (3~4 weeks) during four weeks of experiments period, the herbaceous peat supplement treatments showed a tendency of significant decrease of quality of milk protein and SNF. The control and treatments did not show significant change of blood nutrients (total protein, cholesterol, NEFA, BUN), liver function component (AST, GGT) and minerals (Ca, P, Mg) before and after experiment. In summary, it is judged that herbaceous peat feeding for lactation dairy cows would be recommendable based on the results of milk, somatic cell count physiologically.

• Journal of Internet Computing and Services
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• v.16 no.1
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• pp.57-65
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• 2015

As information technology fusion is accelerated, the researches to improve the quality and productivity of crops inside a plant factory actively progress. Advanced growth environment management technology that can provide thermal environment and air flow suited to the growth of crops and considering the characteristics inside a facility is necessary to maximize productivity inside a plant factory. Currently running plant factories are designed to rely on experience or personal judgment; hence, design and operation technology specific to plant factories are not established, inherently producing problems such as uneven crop production due to the deviation of temperature and air flow and additional increases in energy consumption after prolonged cultivation. The optimization process has to be set up in advance for the arrangement of air flow devices and operation technology using computational fluid dynamics (CFD) during the design stage of a facility for plant factories to resolve the problems. In this study, the optimum arrangement and air flow of air circulation fans were investigated to save energy while minimizing temperature deviation at each point inside a plant factory using CFD. The condition for simulation was categorized into a total of 12 types according to installation location, quantity, and air flow changes in air circulation fans. Also, the variables of boundary conditions for simulation were set in the same level. The analysis results for each case showed that an average temperature of 296.33K matching with a set temperature and average air flow velocity of 0.51m/s suiting plant growth were well-maintained under Case 4 condition wherein two sets of air circulation fans were installed at the upper part of plant cultivation beds. Further, control of air circulation fan set under Case D yielded the most excellent results from Case D-3 conditions wherein air velocity at the outlet was adjusted to 2.9m/s.