• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.382-394
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• 2008

The objective of this study was to analyze temporal trends of water chemistry and spatial heterogeneity between the dam site (Daecheong Reservoir, S1) and the downstream (S2$\sim$S4) using water quality dataset (obtained from the Ministry of Environment, Korea) during 2000$\sim$2007. Water quality, based on eight physical and chemical parameters, varied largely depending on the years, sampling sites, and the discharge volume. Conductivity and nutrients (TN and TP) showed a decreasing trend in the downstream (S4) rather than the dam site during the monsoon. Spatial variation increased toward downstream (S4) from Daecheong Reservoir (S1). Also, BOD and COD increased toward downstream. Because of input of nutrient and pollutant nearby S1, lentic ecosystem in monsoon, BOD and COD were slightly increased. whereas relatively decreased in S4, lotic ecosystem in monsoon, by dilution effect of nutrient and pollutant by discharge from upper dam, S1. Spatial variation of SS increased toward downstream (S4) by the side of Daecheong Reservoir (S1). Based on the dataset, efficient water quality management in the point source tributary streams is required for better water quality of downstream. Monthly characteristics of DO showed the lowest value in the monsoon that tend to increase water temperature. DO was lowest in October at S1 because turbid water, input to the Daecheong Reservoir in the monsoon affect to the postmonsoon period. In contrast, water temperature increased toward summer monsoon, in spite of some differences showed between S1 and S4 environment. Overall, the characteristics of water quality in downstream region have close correlation with discharge amount of Daecheong Reservoir. Thus, those characteristics can explain that discharge control of upper dam mainly affect to the water quality variation in downstream reach.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.773-788
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• 2017

This study was carried out to investigate the damage patterns, the occurrence and migration time of Pseudococcus comstocki and in order to improve the control effect of organic agricultural materials (OAMs). The experiment was carried out at Okcheon's organic vineyard ($2,500m^2$, sandy loam, manure) where planted 8~9 year old 'Muscat of Alexandria' vines. The comstock mealybug's migration to grape clusters occurred from the middle of July, and produced eggs in the grape clusters from the end of July, and the density of the comstock mealybug was highest at $0.6cm^2$ in late August. The number and fruit damage of comstock mealybug in eco-friendly vineyards were higher than in conventional culture vineyard. And the marketability of green variety grape was more damaged from comstock mealybug than the black variety grape. Toxicities of 8 OAMs were evaluated to comstock mealybug at the recommended concentration. As a results, Lightyellow sophora and Derris extracts exhibited strong insecticidal activity with 100% mortality. When the Lightyellow sophora extract was uniformly distributed on the vine from early-July to mid-July, fruit damage reduction rate was 96.2% and 84.6%, respectively. So commercial grapes could be harvested. Therefore, it was considered to be effective to reduce fruit damage by controlling in early - late July (the green stage) when the comstock mealybug migrated to grape clusters in the vine greenhouse. In the future, it will be necessary to study the effect of external exposure time and momentum on the control of OAMs.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.3
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• pp.241-258
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• 1998

The experimental demersal trawl surveys to provide the essential information for the assessment, management and utilization of commercially important fish stocks in the southern waters of Korea were carried out during five research cruises between October 1996 and October 1997 by the training ship “KAYA” of Pukyong National University. The biological sampling was conducted by using the trawl net with a cover net of 36 mm in mesh size at 64 planned trawl stations during daylight to identify the biological characteristics of fish. Each catch was standardized into catch per unit of time and the catches at each trawl station were sorted, weighed and counted by species. The changes in catches of each fish species and the shifts in dominant species by seasions and sampling regions in the research area were analyzed, and the abundance of fish was estimated from the relationship between the trawl catches and the volume of the water column sampled by demersal trawls. The results obtained can be summarized as follows : 1. During the 64 demersal trawls conducted in the southern waters of Korea, 129 species including 112 species of fishes, 8 species of Cephalopoda and 7 species of Crustacea, were identified Also, during the 1996 and 1997 trawl surveys in the reseach area, a large number of commercially important species with small differences in proportion was found. me proportion of Japanese horse mackerel which comprised 19.8% of the total catch by weight was highest, followed by chub mackerel(15.0%), swordtip squid(9.0%), redwing searobin(6.2%), konoshiro gizzard shad(6.1%), Japanese flying squid(5.8%), silver pomfet(5.1%), blackmouth goosefish(5.1%), etc. Swordtip squid, Japanese flying squid, blackmouth goosefish and blackthroat seaperch were among the dominant species in all seasons with a relatively high and stab1e proportion(3.6~9.0%), and were widely distributed in the entire southern water of Korea. 2. The catch rates by cover net varied at 0.7~91.9% by weight of the total trawl catch by codend and cover net at 64 planned trawl stations and the mean catch rate was 44.4%. Species comprising a major portion of the catches by cover net mainly were swordtip squid, konoshiro gizzard shad, the juveniles of Japanese horse mackerel, blackthroat seaperch and chub mackerel, etc. 3. The distribution density of fish in terms of biomass per unit volume which derived from the catch data by 63 bottom trawl hauls in the southern waters of Korea ranged from 17.9 $\times$ 10-6 to 1,440.9 $\times$ 10-6kg/m3 with the mean value of 153.8 $\times$ 10-6 kg/m3. These fish densities varied between seasons, location of sampling stations and sea conditions. From these results, it is worth noting that the catch composition of multispecies and the increased occurrence of small fish in the southern waters of Korea may also result in new problems in determining the total allowable catch(TAC) levels for economically important species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.603-613
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• 1996

Hydrographic conditions (temperature, salinity, dissolved oxygen), nutrients, chlorophyll-a and suspended solid have been studied in the southwestern coastal area of Cheju Island from April 1993 to March 1994. Vertical profile of temperature, salinity and chemical properties (nutrients, chlorophyll-a) distribution in th southwestern sea of Cheju Island showed a upwelling feature. Although it was not clear in winter season, it seems to continued through out the year. In the surface water at the upwelling areas, the ranges of dissolved oxygen, nitrate, phosphate and silicate was $3.30\~8.43\;ml/l,\;0\~7.12{\mu}g/l,\;0.03\~1.75{\mu}g-at/l\;and\;2.75\~22.32\;{\mu}g-at/l$l, respectively. Nutrients was higher in the shore water than in the offshore water, because sufficient supply of nutrients from the bottom water by coastal upwelling. In November, especially high concentration silicate was observed at all the stations and depth in the study area. At all station of bottom water (down to the depth of 60 meter), concentration value of dissolved of gen was as high as 8 ml/l. Mean values of N/P was 8.0, lower than Redifield ratio of 16. The mean values of Si/P was observed to 46.3 in southwest of Cheju Island. Concentration of chlorophyll-a was in the range of $0.04\~2.36\;{\mu}g/l$. Concentration of chlorophyll-a in surface orator at all station was especially higher in spring than in other seasons. Mean concentration value of suspended solids was 3.14 mg/l $(0.75\~8.47\;mg/l)$. Ratio of the volatile suspended solids to the suspended solids was higher in the inshore water $(53\%)$ than in the offshore water $(46\%)$, and higher in the surface water than in the bottom water.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.4
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• pp.72-81
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• 2013

The objective of this study was to verify whether SCB(Slurry Composting & Bio-filtration) system can be applied for the treatment of anaerobic digestion(AD) wastewater and also, to identify the most effective set among three filtration compost beds tested. Results can be summarized as these; (a) When AD wastewater was sprayed on the top of beds which were mainly composed of sawdust and/or other media and, subsequently, filtrates collected and analyzed, there were large drop in the values of Electric Conductivity(EC), Total Suspended Solid(TSS), Biochemical Oxygen Demand(BOD), and Chemical Oxygen Demand(COD). In contrast, Total Nitrgen(T-N) and Total Phosphorus(T-P) were progressively elevated. We consider these changes as positive if the filtrate are to be utilized as liquid fertilizer. (b) When three sets of filtration beds (T1, T2, T3) were compared for their effectiveness, no significant difference was found among them. These indicate that expensive sawdust can be replaced in part with cheaper media such as woodchip, rice husks, or others. (c) At early stage of operation (within 20 days), BOD in filtrates were maintained at high level probably due to the lack of microbial activity. During the same stage, T-N, T-P was at low level but, were elevated to higher levels thereafter. These data, when combined, indicate that the filtration system needs at least a couple of weeks for the optimized microbial functioning. (d) The temperatures of the experimental beds were progressively dropped as the experiment continued through the fall season, although filtration effectiveness was not noticeably influenced.

• Journal of Cadastre & Land InformatiX
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• v.47 no.2
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• pp.107-120
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• 2017

There are many wildfire risk indices worldwide, but objective comparisons between such various wildfire risk indices and surface dryness indices have not been conducted for the wildfire cases in Korea. This paper describes a sensitivity analysis on the wildfire risk indices and surface dryness indices for Korea using LDAPS(Local Analysis and Prediction System) meteorological dataset on a 1.5-km grid and MODIS(Moderate-resolution Imaging Spectroradiometer) satellite images on a 1-km grid. We analyzed the meteorology-based wildfire risk indices such as the Australian FFDI(forest fire danger index), the Canadian FFMC(fine fuel moisture code), the American HI(Haines index), and the academically presented MNI(modified Nesterov index). Also we examined the satellite-based surface dryness indices such as NDDI(normalized difference drought index) and TVDI(temperature vegetation dryness index). As a result of the comparisons between the six indices regarding 120 wildfire cases with the area damaged over 1ha during the period between January 2013 and May 2017, we found that the FFDI and FFMC showed a good predictability for most wildfire cases but the MNI and TVDI were not suitable for Korea. The NDDI can be used as a proxy parameter for wildfire risk because its average CDF(cumulative distribution function) scores were stably high irrespective of fire size. The indices tested in this paper should be carefully chosen and used in an integrated way so that they can contribute to wildfire forecasting in Korea.

• Journal of the Korean Geographical Society
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• v.31 no.3
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• pp.469-488
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• 1996

The defining of weather forecasting regions is possible. since the representativeness of regional weather can by reasonably clarified in terms of weather entropy and the use of information ratio. In this paper, the weather entropy and information ratio were derived numerially from using the information theory. The typical weather characteristics were clarified and defined in the homogeneous weather forecasting regions of the southern parts of Korea. The data used for this study are the daily precipitation and cloudiness during the recent five years (1990-1994) at 42 stations in southern parts of Korea. It is divided into four classes of fine, clear, cloudy and rainy. The results are summarized as follows: 1. The maximum value of weather entropy in study area is 2.009 vits in Yosu in July, and the minimum one is 1.624 bits in Kohung in October. The mean value of weather entropy is maximal in July, on the other hand, minimal in October during four season. The less the value of entropy is, the stabler the weather is. While the bigger the value of entropy is, the more changeable the weather is. 2. The deviation from mean value of weather entropy in southern parts of Korea, with the positive and the negative parts, shows remarkably the distributional tendency of the east (positive) and the west (negative) in January but of the south (positive) and the north (negative) in July. It also clearly shows the distributional tendency of the east (postive) and the west(negative) in the coastal region in April, and of X-type (southern west and northern east: negative) in Chiri Mt. in October. 3. In southern parts, the average information ratio maximaly appear 0.618 in Taegu area in July, whereas minimally 0.550 in Kwangju in October. Particularly the average information ratio of Pusan area is the greatest in April, but the smallest in October. And in Taegu, Kwangju, and Kunsan, it is the greatest in April, January, and July, but the smallest in Jyly, July, and pril. 4.The narrowest appreance of weather representativeness is in July when the Kwangju is the center of the weather forecasting. But the broadest one is in April when Taegu is the center of weather forecasting. 5. The defining of weather forecasting regions in terms of the difference of information ratio most broadly shows up in July in Pusan including the whole Honam area and the southern parts of Youngnam when the Pusan-Taegu is the basis of the application of information ratio. Meanwhile, it appears most broadly in January in Taegu including the whole southern parts except southern coastal area.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.1
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• pp.59-69
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• 2000

Environmental factors and phytoplankton community have been bimonthly investigated in order to clarify the bioecological characteristics of coral habitats around Moonsom at the southern Cheju Island from September 1995 to July 1996. Annual mean temperature and annual mean salinity were $17.4^{\circ}C$ and 34.06 psu, respectively, showing lower temperature-higher salinity in winter and higher temperature-lower salinity in summer, which means such conditions are inadequate for coral reef formation. Nutrient concentrations represent that total nitrogen ranged from $0.07{\sim}10.08\;{\mu}M$, phosphate from $0.05{\sim}1.70\;{\mu}M$, and silicate from $3.08{\sim}21.86\;{\mu}M$. The N/P ratio showed the range of 9.59-10.60 with decreasing offshore-ward, which means the phytoplankton community could be limited by nitrogen sources. Annual mean euphotic depth was 32.0m (18.9m-48.6m) with difference according to season and reveals the close relationship with the depth of coral distribution. Chlorophyll a concentrations of phytoplankton ranged from $0.12{\sim}1.51\;{\mu}g\;L^{-1}$ and standing crops from $1.5{\times}10^3{\sim}7.0{\times}10^5\;cells\;L^{-1}$, showing higher at inshore than at offshore with a blooming in May. A total of 128 species of phytoplankton occurred in all stations, representing 99 spp. of diatoms, 26 spp. of dinoflagellates, 2 spp. of silicoflagellates and 1 sp. of blue-green algae. Diatoms are main taxa in all seasons except for occupying by dinoflagellates in summer. Among dominant species, fParalia sulcata (Ehrenberg) Cleve and Cylindrotheca closterium (Ehrenberg) Lewin & Reimann were predominant and are likely to be main food sources for coral community. Annual mean species diversity index (H') was 1.84, showing lower than around the coast line of Cheju Island.

• Childhood Kidney Diseases
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• v.12 no.1
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• pp.30-37
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• 2008

Purpose: The present study is an investigation of the progression and prognosis of acute intrinsic renal failure in neonates and children with a diagnosis of acute renal failure or other diseases on admission. Methods: This research is based on a retrospective analysis conducted on 59 patients(male: female=2.2:1) diagnosed with acute intrinsic renal failure between January 2000 and June 2006 at Busan Paik Hospital. The clinical diagnostic criteria of acute renal failure used was serum creatinine <1.2 mg/dL, oliguria with urine output$\leq$0.5 mL/kg/hr and anuria with urine output <50 mL per day. Results: Among those placed under investigation, 7 patients were neonates, 10 patients were 2 months-2 years old, 12 patients were 3-6 years old, 21 patients were 7-12 years old and 9 patients were 13-16 years old. It took 3.1${\pm}$2.8 days on average until the diagnosis was made. The urine output distribution was 21 persons for the oliguria group, and 36 persons for the non-oliguria group, and 2 persons for the anuria group. For the underlying causes, 30 persons were classified in the primary renal disease group, 14 persons in the infection group, 9 persons in the malignancy group, and 6 persons were categorized in another group. As for age distribution, the infected group was predominantly neonates, whereas the dominant age ranges for the primary renal disease and infection categories were 2 months to 2 years old. Also, the primary renal disease was dominant among older children, aged 3 and up. No difference was detected according to seasonal prevalence. However, there was a high morbidity rate among hemolytic uremic syndrome diagnosed in the summer. Peritoneal dialysis was used to treat 4 patients. It took 10.0${\pm}$6.7 days until the patients improved. 18 patients died. The non-oliguria group's mortality rate was lower than other groups. There was a high mortality rate in the neonates and malignancy group. Conclusion: Acute renal failure in childhood seems to take a better clinical course than in adulthood when there is an early diagnosis and proper treatment of underlying diseases.

• Weed & Turfgrass Science
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• v.6 no.2
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• pp.86-108
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• 2017

The nationwide weed survey was conducted in arable land, paddy field, upland, orchard and pasture, over whole country of Korea during 3 years from 2013 to 2015. Also, these survey were conducted in order to determine a change of weed community and to identify a major dominant weed species, and problem weeds. Weeds of arable land were composed of 619 species belonging to 81 families. Weeds occurred in paddy field were 90 species belonging to 28 families, upland weeds were 375 species of 50 families, orchard weeds were 492 species of 63 families and pasture weeds 275 species of 52 families. Among total 81 families, the Asteraceae (15.5%) was the biggest family, followed by Poaceae (13.1%), Fabaceae (5.5%), Cyperaceae (5.2%), Polygonaceae (6.3%), respectively. And these weed species were composed of annual weeds of 209 species (33.8%), winter annual of 102 species (16.4%) and perennial weeds of 308 species (49.8%). Exotic weeds naturalized in Korea were investigated as 166 species. Weed flora in Korean cultivation area have been increased as much as 13 families and 186 species for 10 years compared to 2000~2004 weed survey result of 68 families and 433 species. The increment could be resulted from the change of weed population such as increase of the herbicide-resistant and the difference of investigation method.