• Journal of Korean Society of Forest Science
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• v.37 no.1
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• pp.41-56
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• 1978

This experimentation aims to study on the characterics of tree growth by forestry land soil system and the effect of applied fertilizer by kind of tree for obtaining basic data on application of fertilizer to forestry land and to further investigate the restriction factor of tree growth by soil system for promoting more effective application of fertilizer to forestry area. 1. The characteristics of tree growth by soil system showed that tree growth was worst on erosive soil, bad on red or red and yellow soil and generally good on brown soil. 2. With regard to Black Locust, the restriction factor of its growth appeared the content of $P_2O_5$ in the soil and the less the content of $P_2O_5$ is in the soil, the worse its growth was and its growth was bad on clay soil. 3. The growth of pinus seems closely related with the content of $K_2O$ in the soil and the growth of PH was bad on neutral or alkali soil and good on weak-acid soil. Its growth greatly depended upon the content of OM or FN. 4. As Suwon Poplar is a kind of tree requiring for a special soil, its growth required for fertile soil and the content of O. MN $P_2O_5$ $K_2O$ was proportional to its growth. 5. The growth of Black Locust, pinus and Suwon Poplar was good on the soil containing much sand but bad on the soil containing much clay.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.4
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• pp.337-344
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• 2009

This study was conducted to investigate the effects of various cropping system applied with cattle slurry on productivity of sorghum $\times$ sudangrass hybrid (SSH) and environmental pollution in paddy land. cropping systems used in this study were consisted of two designs, such as double-cropping sorghum $\times$ sudangrass hybrid followed by whole crop barley applied with cattle slurry (DSSCS) and mono-cropping sorghum $\times$ sudangrass hybrid followed by hairy vetch used as green manure (MSSGM). The field experiments were conducted on the clay loam at Backsanmyun, Kimje, Chunlabukdo province in Korea for three years (May 2006 to Apr. 2009). This study was arranged in completely randomized design with three replicates. The yield of dry matter (DM) of SSH in DSSCS increased significantly as compared with that of MSSGM (P<0.05). The contents of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF) and total digestible nutrients (TDN) of SSH were not influenced by cattle slurry and green manure. The pH, and contents of OM, T-N and $P_2O_5$ in soil samples collected from DSSCS after the end of experiment were higher than those of MSSGM. The pH, and contents of OM in DSSCS treatment were remarkably higher than those at the beginning of the experiment (p<0.05). However, The pH, and contents of OM in MSSGM treatment were hardly influenced, as compared with those at the beginning of the experiment. The contents of T-N in soil samples collected both from DSSCS snd MSSGM treatments were remarkably higher than those at the beginning of the experiment (p<0.05). In addition, the concentrations of CEC in soil samples collected at the end of the experiment were remarkably higher than those at the beginning of the experiment (p<0.05). The concentrations of $NO_3$-N, $NH_3$-N and $PO_4$-P in leaching water were hardly influenced by the cropping system and application of cattle slurry.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.2
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• pp.137-152
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• 2009

Present experiment was conducted at the field of Gyeongnam Agricultural Research and Extension Services in Jinju city for two continuous cropping seasons to develop several adaptable and valuable year-round forage-producing system for elevating self-sufficiency and dollar-saving by reduced importing of crude forage. Twenty cropping systems were tested in experiment using whole crop barley (WCB), oat, rye, Italian ryegrass (IRG), and triticale in winter season and com, sorghum, sorghum ${\times}$ sudangrass hybrid, and oat in summer time. Sorghum ${\times}$ sudangrass hybrid showed highest fresh forage yield among experimented summer season crops, and followed com. Com produced the most dry matter yield, and followed sorghum${\times}$sudangrass hybrid, sorghum and oat in order. There was no significant effect of former winter crops on fresh and dry matter production succeeding summer time crops. Among winter season forage crops tested, oat showed the highest fresh and dry matter when clipped on mid-May, and followed triticale, IRG, rye and WCB. Winter-time cultivated crops showed no clear effect on the growth and forage (fresh and dry matter) producing ability of following summer crops. There was the most protein content in oat plant among summer season planted crops, and in sorghum for acid detergent fiber (ADF) and in sorghum ${\times}$ sudangrass hybrid for neutral detergent fiber (NDF), respectively. While, com showed highest value of relative feed value (RFV) and total digestive nutrients (TDN) among those crops. Among winter crops, the highest crude protein was in oat plant showing no significant differences of ADF and NDF, while, relatively higher value of RFV was recognized with rye and triticale. Also, triticale contained more TDN as compare to other forage crops. The cropping combinations such as com followed by (fb) rye and maize fb triticale were regarded as promising systems having higher dry matter producing ability among tested combinations. Considering TDN producing potential, the combinations with sorghum ${\times}$ sudangrass hybrid fb triticale andlor rye were would be suitable ones, coincidently. There was a tendency which elevating pH, electric conductivity (EC) and organic matter (OM) contents in soil after experiment comparing to before planting. More crude protein content in plant was shown at mid-May clipping as compared to the forage at April cut in all winter season grown crops. ADF and NDF contents were increased by delayed clipping showing decreased tendency of RFV and TDN in plant. In conclusion, many cropping systems would be available using above mentioned forage crops according to farmer's conditions and scale, etc.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.554-568
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• 2021

Forests are the largest carbon (C) sinks in terrestrial ecosystems. Recently, as enhancing forest C sequestration capacity has been proposed as a basic direction of the Republic of Korea's "2050 Carbon Neutral Strategy," accurate estimation of forest C sequestration has been emphasized. According to the Intergovernmental Panel on Climate Change guidelines, sequestration quantity is calculated from changes in C stocks in forest C pools, such as biomass, deadwood, litter and soil layer, and harvested wood products. However, in Korea, only the overstory biomass increase is now considered the amount of sequestration quantity, so there can be a significant difference from the actual forest C sequestration. In this study, we quantified forest C exchange through C flux measurement using an eddy covariance system and an automated soil chamber system in a 57-year-old Korean pine plantation located in Mt. Taehwa, Gwangju-si, Gyeonggi-do. Then, the net amount of C sequestration was compared with the amount of the overstory biomass increase. We estimated the annual C stock change in the remaining C pools by comparing the net sequestration amount from the C flux measurement with the overstory biomass increase and C stock change in the litter layer. Therefore, the net C sequestration of the Korean pine plantation estimated from the flux measurement was 5.96 MgC ha^-1, which was about 2.2 times greater than 2.77 MgC ha^-1 of the overstory biomass increase. The annual C stock increase in the litter layer was estimated to be 0.75 MgC ha^-1, resulting in a total annual C stock increase of 2.45 MgC ha^-1 in the remaining C pools. Our results indicate that the domestic forest is a larger C sink than the current methods, implying that more accurate calculations of the C sequestration capacity are necessary to quantify C stock changes in C pools along with the C flux measurement.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.1
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• pp.35-41
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• 2023

This experiment was carried out to examine double cropping system using Italian ryegrass (IRG) 'Kowinearly', whole crop rice 'Yeongwoo' and barnyard millet 'Jeju native' during the Oct. 2020 to Oct. 2022. Three kinds of forage crops were cultivated at paddy field in Livestock Institute, Jeollanamdo Agricultural Research and Extension Services, Jeollanamdo, South Korea. Whole crop rice (WCR) was sown in late May and barnyard millet (BM) sown early June each year after harvesting IRG. We examined dry matter yield and feed value of forage crops depending on harvest time of forage crops during the experimental period. The plant height in heading stage of IRG ranged from 108 to 112cm and dry matter yield ranged from 6,783 to 11,530 kg ha^-1. The crude protein (CP) of IRG ranged from 6.0 to 8.44%, acid detergent fiber (ADF) ranged from 55.6 to 60.2% and neutral detergent fiber (NDF) ranged from 32.58 to 36.7%, The dry matter yield of WCR increased as the harvest stage was delayed (14,310 kg ha^-1 in milk, 16,167 kg ha^-1 in yellow ripen, and 18,891 kg ha^-1 in mature). Similar to results of dry matter yield of WCR, dry matter yield of BM increased as the harvest stage was delayed (11,194 kg ha^-1 in late heading. and 14,308 kg ha^-1 in mature), However nutrient content of WCR and BM showed a decreasing trend. As shown in above results, the productivity of WCR after harvesting IRG was shown to be high at paddy field in the southern region. However, BM also was appeared to have potential as summer forage crops.

• Journal of Space Technology and Applications
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• v.4 no.3
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• pp.210-219
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• 2024

This study investigates various ionospheric and thermospheric disturbances around the Korean Peninsula during the G5 geomagnetic storm occurred on May 10, 2024. This level of storm was the first of its magnitude in 21 years, resulting in auroras visible even in South Korea and severe space weather worldwide. The Korea Astronomy and Space Science Institute has been providing ionospheric information over Korea through total electron content (TEC) measurements from the Global Navigation Satellite System (GNSS) and monitoring the impact of ionospheric disturbances on GNSS signals by operating five GNSS scintillation stations in Korea and other countries. During this storm period, large amplitudes of TEC variations were observed over South Korea, along with anomalous TEC enhancements accompanied by strong scintillations at night and persistent TEC depletion on the dayside during the storm's recovery phase. Such daytime TEC depletion disturbances are quite rare, typically occurring only a few times throughout the 11-year solar cycle. While the association of persistent TEC depletion during the daytime with neutral composition disturbances was identified through observations, the causes of TEC enhancement and strong scintillation at night remain unclear. We speculate that the uplift of the ionosphere by storm-induced electric fields is responsible for the TEC enhancement and scintillation, but this hypothesis requires validation based on additional observational data.

• Journal of Intelligence and Information Systems
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• v.25 no.2
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• pp.39-55
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• 2019

Recently banks and large financial institutions have introduced lots of Robo-Advisor products. Robo-Advisor is a Robot to produce the optimal asset allocation portfolio for investors by using the financial engineering algorithms without any human intervention. Since the first introduction in Wall Street in 2008, the market size has grown to 60 billion dollars and is expected to expand to 2,000 billion dollars by 2020. Since Robo-Advisor algorithms suggest asset allocation output to investors, mathematical or statistical asset allocation strategies are applied. Mean variance optimization model developed by Markowitz is the typical asset allocation model. The model is a simple but quite intuitive portfolio strategy. For example, assets are allocated in order to minimize the risk on the portfolio while maximizing the expected return on the portfolio using optimization techniques. Despite its theoretical background, both academics and practitioners find that the standard mean variance optimization portfolio is very sensitive to the expected returns calculated by past price data. Corner solutions are often found to be allocated only to a few assets. The Black-Litterman Optimization model overcomes these problems by choosing a neutral Capital Asset Pricing Model equilibrium point. Implied equilibrium returns of each asset are derived from equilibrium market portfolio through reverse optimization. The Black-Litterman model uses a Bayesian approach to combine the subjective views on the price forecast of one or more assets with implied equilibrium returns, resulting a new estimates of risk and expected returns. These new estimates can produce optimal portfolio by the well-known Markowitz mean-variance optimization algorithm. If the investor does not have any views on his asset classes, the Black-Litterman optimization model produce the same portfolio as the market portfolio. What if the subjective views are incorrect? A survey on reports of stocks performance recommended by securities analysts show very poor results. Therefore the incorrect views combined with implied equilibrium returns may produce very poor portfolio output to the Black-Litterman model users. This paper suggests an objective investor views model based on Support Vector Machines(SVM), which have showed good performance results in stock price forecasting. SVM is a discriminative classifier defined by a separating hyper plane. The linear, radial basis and polynomial kernel functions are used to learn the hyper planes. Input variables for the SVM are returns, standard deviations, Stochastics %K and price parity degree for each asset class. SVM output returns expected stock price movements and their probabilities, which are used as input variables in the intelligent views model. The stock price movements are categorized by three phases; down, neutral and up. The expected stock returns make P matrix and their probability results are used in Q matrix. Implied equilibrium returns vector is combined with the intelligent views matrix, resulting the Black-Litterman optimal portfolio. For comparisons, Markowitz mean-variance optimization model and risk parity model are used. The value weighted market portfolio and equal weighted market portfolio are used as benchmark indexes. We collect the 8 KOSPI 200 sector indexes from January 2008 to December 2018 including 132 monthly index values. Training period is from 2008 to 2015 and testing period is from 2016 to 2018. Our suggested intelligent view model combined with implied equilibrium returns produced the optimal Black-Litterman portfolio. The out of sample period portfolio showed better performance compared with the well-known Markowitz mean-variance optimization portfolio, risk parity portfolio and market portfolio. The total return from 3 year-period Black-Litterman portfolio records 6.4%, which is the highest value. The maximum draw down is -20.8%, which is also the lowest value. Sharpe Ratio shows the highest value, 0.17. It measures the return to risk ratio. Overall, our suggested view model shows the possibility of replacing subjective analysts's views with objective view model for practitioners to apply the Robo-Advisor asset allocation algorithms in the real trading fields.

• Economic and Environmental Geology
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• v.56 no.5
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• pp.603-618
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• 2023

This study focused on evaluating the suitability of the WRK (waste repository Korea) bentonite as a buffer material in the SNF (spent nuclear fuel) repository. The U (uranium) adsorption/desorption characteristics and the adsorption mechanisms of the WRK bentonite were presented through various analyses, adsorption/desorption experiments, and kinetic adsorption modeling at various pH conditions. Mineralogical and structural analyses supported that the major mineral of the WRK bentonite is the Ca-montmorillonite having the great possibility for the U adsorption. From results of the U adsorption/desorption experiments (intial U concentration: 1 mg/L) for the WRK bentonite, despite the low ratio of the WRK bentonite/U (2 g/L), high U adsorption efficiency (>74%) and low U desorption rate (<14%) were acquired at pH 5, 6, 10, and 11 in solution, supporting that the WRK bentonite can be used as the buffer material preventing the U migration in the SNF repository. Relatively low U adsorption efficiency (<45%) for the WRK bentonite was acquired at pH 3 and 7 because the U exists as various species in solution depending on pH and thus its U adsorption mechanisms are different due to the U speciation. Based on experimental results and previous studies, the main U adsorption mechanisms of the WRK bentonite were understood in viewpoint of the chemical adsorption. At the acid conditions (＜pH 3), the U is apt to adsorb as forms of UO₂²⁺, mainly due to the ionic bond with Si-O or Al-O(OH) present on the WRK bentonite rather than the ion exchange with Ca²⁺ among layers of the WRK bentonite, showing the relatively low U adsorption efficiency. At the alkaline conditions (>pH 7), the U could be adsorbed in the form of anionic U-hydroxy complexes (UO₂(OH)₃^-, UO₂(OH)₄^2-, (UO₂)₃(OH)₇^-, etc.), mainly by bonding with oxygen (O^-) from Si-O or Al-O(OH) on the WRK bentonite or by co-precipitation in the form of hydroxide, showing the high U adsorption. At pH 7, the relatively low U adsorption efficiency (42%) was acquired in this study and it was due to the existence of the U-carbonates in solution, having relatively high solubility than other U species. The U adsorption efficiency of the WRK bentonite can be increased by maintaining a neutral or highly alkaline condition because of the formation of U-hydroxyl complexes rather than the uranyl ion (UO₂²⁺) in solution,and by restraining the formation of U-carbonate complexes in solution.

• Journal of Animal Science and Technology
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• v.44 no.2
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• pp.239-250
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• 2002

Evaluation works of oat in mixture with rye on forage yield have not been reported. The objective of this study was to determine yield and quality of forage mixture as affected by maturity of rye cultivar and oat-rye seeding rate at Suweon from 1999 to 2000. The experiment was arranged in a split plot design with three replications. Main plots consisted of maturity of rye. such as early(cv. Koolgrazer) and late(cv. Kodiak)maturing cultivars. Sub-plots consisted of seeding rate (T1: Oat 2000 and rye 0kg/ha, Ts: Oat 150 and rye 40kg/ha, T3: Oat100 and rye 80kg/ha, T4: Oat50 and rye 120kg/ha. and T5: Oat0 and rye 160kg/ha). Crude protein(CP) content of oat-rye mixture harvested in the fall was not influenced by maturity of rye cultivar, but that of oat-rye mixture was increased from 13.6 to 19.3% as the seeding rate of rye increased(P<0.05), however, maturity of rye cultivar significantly affected CP content of oat-rye mixture in the spring(P<0.01). Acid detergent fiber(ADF) content of oat-rye mixture harvested in the spring was not significantly affected by rye cultivar, but the ADF was decreased from 27.8 to 20.7% as the seeding rate of rye increased(P$<$0.01). When rye was harveste in the spring, ADF content of late maturing cultivar 'Kodiak' was shown as 28.0%. This was lower than that of early maturing cultivar 'Koolgrazer' which was shown as 35.8%(P$<$0.01). Among treatments, neutral detergent fiber(NDF) and in vitro dry matter digestibility(IVDMD) of oat-rye mixture showed a similar trend made on ADF. In this experiment, the highest forage yield (12.356kg/ha) was obtained from early maturing rye cultivar and seeding rates of 100kg/ha of oat and 80kg/ha of rye mixture. A significant interaction between maturity of rye cultivar and seeding rate was found(P$<$0.01). The above results indicate that an early maturing rye cultivar at the seeding rate of 100kd/ha in mixtures with 80kg/ha of oat could be recommended as a succeeding cropping system after corn for silage.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.709-716
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• 1998

Three kinds of anti-complementary system and macrophage activating polysaccharides, AB-20-Ia, AB-20-IIa-2a and AB-20-IVa-2 were isolated from the fruit body of Agaricus bisporus and their structures were characterized. The proteoglycan, AB-20-IVa-2 showing the most potent anti-complementary and macrophage activity was composed of glucose, galactose, mannose, xylose, fucose and arabinose in a molar ratio of 3.48:1.83:1.00:0.79:0.74:0.11 and its main component amino acids were phenylalanine (34.72%) and valine (27.84%). The neutral polysaccharides, AB-20-Ia and AB-20-IIa-2a showing lower activity than AB-20-IVa-2, consisted of xylose, glucose, mannose, fucose and arabinose in molar ratios of <0.05:<0.05:2.07:1.00:2.72 and 2.16:1.58:1.00:0.20:0.14, respectively. The molecular weights of AB-20-Ia, AB-20-IIa-2a and AB-20-IVa-2 were 840,000, 750,000 and 650,000 respectively. In the $^1H-\;and\;^{13}C-NMR$ spectra of AB-20-Ia and AB-20-IIa-2a, AB-20-Ia showed only ${\beta}-configuration\;(^1H:\;4.8\;ppm,\;^{13}C:\;107.0\;ppm)$ in the anomerization of the glycosidic linkages, while AB-20-IIa-2a had both ${\alpha}-anomer\;(^1H:\;5.4\;ppm,\;^{13}C:\;102.0\;ppm)\;and\;{\beta}-anomer$. Especially, AB-20-Ia and AB-20-IIa-2a showed acetyl signals $(^1H:\;2.5\;ppm,\;^{13}C:\;21.0\;ppm)$. In the methylation analysis of the three polysaccharides, high proportion of 1,6-linked glucofuranosyl residues were detected in AB-20-Ia, whereas 1,6-linked glucopyranosyl residues and branches linked at position 4 of those mainly contained in AB-20-IIa-2a. AB-20-IVa-2 consisted mainly of 1,2-linked xylofuranosyl residues and 1,6-linked glucopyranosyl residues and branches linked at position 3 of those.