• Journal of Korean Society of Environmental Engineers
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• v.33 no.1
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• pp.25-31
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• 2011

In this study, model-based $NH_4-N$ predictive control algorithm by using influent pattern was developed and evaluated for effective control application in $A^2/O$ process. A pilot-scale $A^2/O$process at S wastewater treatment plant in B city was selected. The behaviors of organic, nitrogen and phosphorous in the biological reactors were described by using the modified ASM3+Bio-P model. A one-dimensional double exponential function model was selected for modeling of the secondary settlers. The effluent $NH_4-N$ concentration on the next day was predicted according to model-based simulation by using influent pattern. After the objective effluent quality and simulation result were compared, the optimal operational condition which able to meet the objective effluent quality was deduced through repetitive simulation. Next the effluent $NH_4-N$ control schedule was generated by using the optimal operational condition and this control schedule on the next day was applied in pilot-scale $A^2/O$ process. DO concentration in aerobic reactor in predictive control algorithm was selected as the manipulated variable. Without control case and with control case were compared to confirm the control applicability and the study of the applied $NH_4-N$control schedule in summer and winter was performed to confirm the seasonal effect. In this result, the effluent $NH_4-N$concentration without control case was exceeded the objective effluent quality. However the effluent $NH_4-N$ concentration with control case was not exceeded the objective effluent quality both summer and winter season. As compared in case of without predictive control algorithm, in case of application of predictive control algorithm, the RPM of air blower was increased about 9.1%, however the effluent $NH_4-N$ concentration was decreased about 45.2%. Therefore it was concluded that the developed predictive control algorithm to the effluent $NH_4-N$ in this study was properly applied in a full-scale wastewater treatment process and was more efficient in aspect to stable effluent.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.2
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• pp.51-59
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• 2017

This study evaluated the drought tolerance of Liriope platyphylla F.T.Wang & T.Tang, Dendranthema zawadskii var. lucidum (Nakai) J.H.Park, Hosta longipes (Franch. & Sav.) Matsum., Sedum sarmentosum Bunge and Zoysia japonica Steud. for an extensive green roof. In order to assess drought tolerance of green roof plants, several criteria were measured such as volumetric water content, leaf and soil moisture potential, chlorophyll a and b, chlorophyll fluorescence, photosynthesis, stomatal conductance, transpiration rate and antioxidants. The results of the drought tolerance measurement of green roof plants focused on the gradually withering of plants from lack of volumetric water content. D. zawadskii was the first to show an initial wilting point, followed by Z. japonica, H. longipes and L. platyphylla in order while S. sarmentosum showed no withering. It was concluded that H. longipes, L. platyphylla and S. sarmentosum were highly drought tolerant plants able to survive over three weeks. Furthermore, chlorophyll a and b were divided into two types: Type I, which kept regular content from the beginning to the middle of the period and suddenly declined, like H. longipes and Z. japonica; and Type II, which showed low content at the beginning, sharply increased at the middle stage and decreased, like D. zawadskii, L. platyphylla and S. sarmentosum. Volumetric water content and the amount of evapotranspiration consistently declined in all plant species. The analysis of chlorophyll fluorescence results that S. sarmentosum, which had relatively high drought tolerance, was the last to decline, while Z. japonica and S. sarmentosum withered after rapid reduction. At first, photosynthesis, stomatal conductance and transpiration rate showed high activity, but they lowered as the plant body closed stomata owing to the decrease in volumetric water content. Measuring antioxidants showed that when drought stress increased, the amount of antioxidants grew as well. However, when high moisture stress was maintained, this compound was continuously consumed. Therefore, the variation of antioxidants was considered possible for use as one of the indicators of drought tolerance evaluation.

• Korean Journal of Plant Taxonomy
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• v.32 no.3
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• pp.339-362
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• 2002

Pollen morphology of 13 species of Korean Euphorbia was re-examined by means of LM and SEM. Taxonomic evaluation of palynological characters and relationships among taxa were also discussed based on the analysis of polar length, equatorial diameter, aperture size and exine thickness. Korean Euphorbia species were classified into three groups based on the mean size of polar length (P) and equatorial diameter (E) as follows:Group 1. sect. Tulocarpa and Tithymalus of subgenus Esula; $(P){\times}(E)=(54.88-67.17{\mu}m){\times}(44.30-64.75{\mu}m)$, Group 2. sect. Esula and Helioscpiae of subgenus Esula; $(P){\times}(E)=(39.98-47.24{\mu}m){\times}(36.07-38.83{\mu}m)$, Group 3. sect. Chamaesyce and Hypericifoliae of subgenus Chamaesyce; $(P){\times}(E)=(30.32-32.51{\mu}m){\times}(21.71-26.23{\mu}m)$. Various features of surface sculpturing were also grouped into 8 types by the characteristics of perporation size and distance of perporations as well as connection state of it. Pollen size and surface sculpturing were comparatively available in the levels of subgenus and section. Especially subgenus Chamaesyce was distinctly different from subgenus Esula by having compactly distributed perporations on exine surface as well as its small size of pollen grains. Because of the great variations in pollen size and the occurrence of various types of surface sculpturing according to the local poulations of each species, it was evaluated that they were unsuitable in classifying each species of Euphorbia. But such cases, that is, E. hylonoma being more familiar with E. ebracteolata than E. Pallasii, and E. pekinensis and E. fauriei as well as E. pallasii being strongly related with each other based on the similarity of surface sculpturing, reflected its usefulness in the classification of some Euphorbia species.

• Korean Journal of Plant Resources
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• v.31 no.4
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• pp.303-311
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• 2018

In this study, a preliminary evaluation of the antioxidant and anti-inflammatory activity of the Ficus erecta var. sieboldii (Miq.) King (FES) leaf extract has been performed to assess its potential as a natural resource for food and medicinal materials. FES was extracted using 70% EtOH and then fractionated sequentially using n-hexane, $CH_2Cl_2$, EtOAc, and n-BuOH. To screen for antioxidant and anti-inflammatory agents effectively, the inhibitory effect of the FES extracts on the production of oxidant stresses (DPPH, xanthine oxidase, and superoxide) and pro-inflammatory factors (NO, iNOS, COX-2, $PGE_2$, IL-6, and $IL-1{\beta}$) in the murine macrophage cell line RAW 264.7 activated with lipopolysaccharide (LPS) was examined. Among the sequential solvent fractions of FES, the $CH_2Cl_2$ and EtOAc fractions showed decreased production of oxidant stresses (DPPH, xanthine oxidase and superoxide), and the hexane and $CH_2Cl_2$ fractions of FES inhibited the production of pro-inflammatory factors (NO, iNOS, COX-2, and $PGE_2$). The $CH_2Cl_2$ fraction also inhibited the production of pro-inflammatory cytokines ($TNF-{\alpha}$, IL-6, and $IL-1{\beta}$). These results suggest that FES has a significant effects on the production of oxidant stresses and pro-inflammatory factors and may be used a natural resource for antioxidant and anti-inflammatory agents.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.667-673
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• 2011

There is relatively high vulnerability of soil erosion in slope highland agriculture due to a reclamation of mountain as well as low surface covering in early summer season with high rainfall intensity time. The aim of this study was to evaluate various surface covering methods for reducing soil loss in highland radish cultivation in highland. The experiment was conducted in 17% sloped lysimeter ($2.5m{\times}13.4m$) with 8 treatments including covering with cut rye, sod culture of rye, Ligularia fischeri var. spiciformis Nakai, Arachniodes aristata Tindale, Aster koraiensis Nakai, Festuca myuros L. and mulching with black polyethylene film, and runoff water, eroded soil and radish growth were investigated. Surface covering with sod culture and plant residue, especially cut rye treatment, had lower runoff water than non-covering, whereas black polyethylene film mulching had the reverse. The amount of eroded soil was also lowest in cut rye treatment, $0.3Mg\;ha^{-1}$, and increased in the order of rye sod culture, Ligularia fischeri var. spiciformis Nakai, Aster koraiensis Nakai, Festuca myuros L., Arachniodes aristata Tindale, black polyethylene film, and non-covering, $68.2Mg\;ha^{-1}$. The results showed that surface covering with sod culture or plant residue could be effective for reducing runoff water and soil erosion in the radish field, significantly in cut rye treatment. On the other hand, in sod culture of rye, Aster koraiensis Nakai and Ligularia fischeri var. spiciformis Nakai, radish yields were lower than in the non-covering. Unlike this, covering with cut rye, sod culture of Festuca myuros L. had similar radish yield to the non-covering radish yield. In conclusion, covering with cut rye and sod culture of Festuca myuros L. were beneficial for reduction of soil loss without decreasing in radish yield in highland sloped fields.

• Journal of Korea Water Resources Association
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• v.54 no.10
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• pp.819-833
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• 2021

This study is to evaluate applicability of linkage modeling using PHABSIM (Physical Habitat Simulation System) and SWAT (Soil and Water Assessment Tool) and to estimate ecological flow for target fishes of Andong downstream (4,565.7 km²). The SWAT was established considering 2 multi purpose dam (ADD, IHD) and 1 streamflow gauging station (GD). The SWAT was calibrated and validated with 9 years (2012 ~ 2020) data of 1 stream (GD) and 2 multi-purpose dam (ADD, IHD). For streamflow and dam inflows (GD, ADD and IHD), R², NSE and RMSE were 0.52 ~ 0.74, 0.48 ~ 0.71, and 0.92 ~ 2.51 mm/day respectively. As a result of flow duration analysis for 9 years (2012 ~ 2020) using calibrated streamflow, the average Q185 and Q275 were 36.5 m³/sec (-1.4%) and 23.8 m³/sec (0%) respectively compared with the observed flow duration and were applied to flow boundary condition of PHABSIM. The target stream was selected as the 410 m section where GD is located, and stream cross-section and hydraulic factors were constructed based on Nakdong River Basic Plan Report and HEC-RAS. The dominant species of the target stream was Zacco platypus and the sub-dominant species was Puntungia herzi Herzenstein, and the HSI (Habitat Suitability Index) of target species was collected through references research. As the result of PHABSIM water level and velocity simulation, error of Q185 and Q275 were analyzed -0.12 m, +0.00 m and +0.06 m/s, +0.09 m/s respectively. The average WUA (Weighted Usable Area) and ecological flow of Zacco platypus and Puntungia herzi Herzenstein were evaluated 76,817.0 m²/1000m, 20.0 m³/sec and 46,628.6 m²/1000m, 9.0 m³/sec. This results indicated Zacco platypus is more adaptable to target stream than Puntungia herzi Herzenstein.

• Ecology and Resilient Infrastructure
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• v.8 no.4
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• pp.290-298
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• 2021

This study was conducted to evaluate the possibility of applying phytoremediation technology by investigating soil and native plants in waste coal landfills exposed to heavy metal contamination for a long period of time. The ability of native plants to accumulate heavy metals using greenhouse cultivation experiments was alse evaluated. Plants were investigated at an abandoned coal mine in Hwajeolyeong, Jeongseon, Gangwon-do. Two species of native plants (Carex breviculmis. R. B. and Salix koriyanagi Kimura ex Goerz.) located in the study area and three Korean native plants (Artemisia japonica Thunb. Hemerocallis hakuunensis Nakai., and Saussurea pulchella (Fisch.) Fisch.) were cultivated in a greenhouse for 12 weeks in artificially contaminated soil. Soils contaminated with arsenic and lead were generated with arsenic concentration gradients of 25, 62.5, 125, and 250 mg kg^-1 and lead concentration gradients of 200, 500, 1000, and 2000 mg kg^-1, respectively. Results showed that none of the five plants could survive at high arsenic concentration treatment (125 and 250 mg kg^-1) and some plants died in 2000 mg kg^-1 lead concentration treatment soil. The plant translocation factor (TF) was highest in H. hakuunensis in arsenic treatments, and A. japonica in lead treatments, respectively. The bioaccumulation factor (BF) of plants was more than 1 in all species in arsenic treatment, whereas it was highest in H. hakuunensis. BF for all species was less than 1 in lead treatment. Particularly, in 2000 mg kg^-1 concentration lead treatment, A. japonica accumulated more than 1000 mg kg^-1 lead and was expected to be a lead hyperaccumulator. In conclusion, A. japonica and H. hakuunensis were excellent in the accumulation of arsenic heavy metals, and S. koriyanagi was excellent in lead accumulation ability. Therefore, the above mentioned three plants are considered to be strong contenders for application of the phytoremediation technology.

• Research in Plant Disease
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• v.25 no.3
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• pp.108-113
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• 2019

Almost 30% of arable lands of North Korea are covered with paddy rice. In rice cultivation of North Korea, rice blast disease is the most important fungal disease and bacterial leaf blight is the most important bacterial disease. Seven North Korean rice cultivars had been tested for the disease resistance against rice blast pathogen, Magnaporthe oryzae and bacterial leaf blight pathogen, Xanthomonas oryzae pv. oryzae. The responses of seven cultivars against 17 different M. oryzae races from South Korea had been quite different. Among seven cultivars, Giljoo1ho was very resistant to all 18 different M. oryzae isolates from South Korea, nevertheless KI or KJ. Pyungdo5ho was very susceptible, it showed susceptible responses to 8 out of 10 KI races and 7 out of 8 KJ races of M. oryzae isolated in South Korea. However, the response to bacterial leaf blight was different from the response to rice blast pathogen. Gijoo1ho, Wonsan69ho, Onpo1ho, and Pyungdo15ho were susceptible to KXO42 (K1) and KXO90 (K2), respectively. Pyungdo5ho was resistant to KXO85 (K1) and KXO19 (K3), and Pyungyang21ho was resistant to K1 races. Based on these results, Giljoo1ho can be a good resource for the breeding of resistant rice cultivar against M. oryzae isolates from South Korea.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.1
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• pp.65-73
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• 2019

The MODIS (Moderate Resolution Imaging Spectroradiometer) data in Hierarchical Data Format (HDF) have been processed using the Geospatial Data Abstraction Library (GDAL). Because of a relatively large data size, it would be preferable to build and install the data analysis tool with greater computing performance, which would differ by operating system and the form of distribution, e.g., source code or binary package. The objective of this study was to examine the performance of the GDAL for processing the HDF files, which would guide construction of a computer system for remote sensing data analysis. The differences in execution time were compared between environments under which the GDAL was installed. The wall clock time was measured after extracting data for each variable in the MODIS data file using a tool built lining against GDAL under a combination of operating systems (Ubuntu and openSUSE), compilers (GNU and Intel), and distribution forms. The MOD07 product, which contains atmosphere data, were processed for eight 2-D variables and two 3-D variables. The GDAL compiled with Intel compiler under Ubuntu had the shortest computation time. For openSUSE, the GDAL compiled using GNU and intel compilers had greater performance for 2-D and 3-D variables, respectively. It was found that the wall clock time was considerably long for the GDAL complied with "--with-hdf4=no" configuration option or RPM package manager under openSUSE. These results indicated that the choice of the environments under which the GDAL is installed, e.g., operation system or compiler, would have a considerable impact on the performance of a system for processing remote sensing data. Application of parallel computing approaches would improve the performance of the data processing for the HDF files, which merits further evaluation of these computational methods.

• Journal of Bio-Environment Control
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• v.31 no.1
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• pp.43-51
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• 2022

This study was conducted to investigate the effect of ventilation at high temperature on the control of powdery mildew, silverleaf whitefly two-spotted spider mite occurred at Korean melon cultivation greenhouse, and on leaf rolling and flowering of the plant in summer season. 'Alchanggul' grafted onto 'Hidden Power' rootstock was planted on soil bed with the distance of 40 cm. Three ventilation temperatures of 45℃, 40℃, and 35℃ as set points were compared. Ventilation treatment was done by control of side window operation from 18th June to 13th July when silverleaf whitefly, mite, and powdery mildew were occurred in all greenhouses. The temperature inside greenhouse was increased up to the set temperature point on sunny days and maintained for about 9 hours with high relative humidity at 45℃ condition. The differences of day maximum air temperature and day minimum RH were the highest at 45℃ treatment. After 11 days of treatments, the damage by powdery mildew and two-spotted spider mite was almost recovered at 45℃ treatment but not at 40 and 35℃. The population of silverleaf whitefly and two-spotted spider mite were significantly decreased at 45℃ treatment at 14 days after treatment, while powdery mildew symptom was not significantly decreased. Leaf rolling was observed at high temperature but not severe at 45℃ treatment. After 26 days of treatments, female flowers did not bloom at all at 45℃ treatment, and the number of male flowers was 1.2 among 15 nodes of newly grown shoots. As the result, it indicates that ventilation at the high temperature of 45℃ for about 2 to 3 weeks can be an applicable method to control above mentioned pests and disease, and to recover the vegetative growth of Korean melon by reducing flowering of the plant.