• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.241-241
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• 2017

Sweet potatoes (Ipomoea batatas (L.) LAMK.,) have been cultivated in Central and South America for about 2000 years and are now grown mainly in Asia and South America. Sweet potatoes are annual in the temperate region, but are classified as perennial in the tropical region. In 2000, the cultivation area of sweet potatoes decreased to about 16,000 ha in 2000, but the cultivation area increased slightly in recent 20,000 ha in Korea. Sweet potatoes do not show higher maximum dry matter production of 120 ~ 150g per plant, and the leaf area index (LAI), which maximizes dry matter production, is known as 3.0 ~ 4.0. As the leaf area increase, the penetration of light into the canopy becomes poor, and sufficient photosynthesis cannot be achieved in the lower leaves, on the other hand the respiration increase, which results in poor dry matter production. This study was conducted to know the responses of sweet potatoes to intensive shading treatment of 80% shading. This experiment was conducted for about 42 days from September 6, 2016 to October 18, 2016 at Gyeongsang National University Experimental Farm, Jinju, Korea. The plant canopy was shaded with black nylon 80% shade cloth suspended 1.2 m above the ground. The photosynthetic rate, stomatal conductance, chlorophyll fluorescence, SPAD and NDVI were measured in 3 replicates every 7 days after shading initiation. After the fresh weight was measured, the samples were dried at $80^{\circ}C$ in a dry oven and measured. By the 80% shading treatment, chlorophyll fluorescence of the treated plants was slightly higher than that of the control, the SPAD value was higher by 3.4 and NDVI value was higher by 0.01. However, photosynthetic rate and stomatal conductance were lower than those of the control. The stomatal conductance of the control were two times higher than those of the control and the photosynthetic rate of the control was four times higher than that of the control. In control, plant showed a tendency to steadily increase in fresh weight and dry weight. However, in the case of shading treatment, the tendency to increase in the fresh and dry weight of tuberous roots was not clear. The fresh weight of shoot showed a tendency to increase steadily while the difference between treatment and control was not large, but tended to decrease after frost.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.4
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• pp.243-246
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• 2018

This study was carried out to identify the effect of the rate of botanical composition, dry matter yield and liveweight gain of horse by renewing low productive pasture. According to the first survey (5.11) before grazing, No.64 was the highest at 81%, followed by No.39 71%t and No.44 65%. For the second and third surveys, the rate of pasture was relatively low, except for No.64. Annual total DM production was the highest at No.44 13,459 kg/ha, then with No.64 and No.39, productivity was 13,232kg/ha and 12,042kg/ha, respectively. No.44 and No.39, the confluence of orchardgrass and perennial ryegrass, showed a sharp decline because of summer depression after the second survey. The livestock growth rate per 10,000 square meters was 70kg, compared with 47.5kg and 36.2kg, respectively. The daily livestock gains in No.39, No.44, and No.66 was 1.09 kg, 1.08 kg and 1.03 kg, respectively.

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.519-527
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• 1998

An economic study of vegetation control to increase production of Songyi (Korean name far pine mushroom, matsutake, Tracholoma matsutake (S. Ito & Imai) Sing.) in red pine (Panes densiflora) stands in Korea was undertaken. In Korea, Songyi grows only in red pine stands. Harvest of this mushroom provides a significant income source to rural people in Korea yielding exports of US$20 million to US$80 million per year. However, hypogeous Songyi colonies and the mushroom production are declining, partly because shade tolerant species are succeeding the shade intolerant red pine. Past research says that it is possible to deep Songyi production increasing by controlling under-story vegetation. But few people are wilting to invest in the necessary control. Our analysis found that the economics of vegetation control appear to be quite favorable, showing an internal rate of return (IRR) of 20.7 percent in 15 years. However, positive returns do not occur for at least eight years and even then, the returns may not appear to the landowner to be a result of vegetation control efforts only because the mushroom production has been greatly variable depending on weather conditions. In a sensitivity analysis, it was found that the number of circular mushroom colonies was critically important for the cash flow. Results of this analysis are also sensitive to assumptions about annual growth length(0.16m radial growth=1.0m/circular length growth) of Songyi colony. However, the primary goal of vegetation control should be to keep the young colonies growing. Further research in the behavior of hypogeous Songyi colonies after vegetation control would help to improve our confidence in the results.

• Journal of the Korean Society for information Management
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• v.29 no.4
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• pp.143-163
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• 2012

The dominant model of acquiring scholarly contents at academic libraries is so called big deal where libraries subscribe to a bundle of hundreds, if not thousands of journals in a multi-year contract with fixed annual rate increase. The bid deal, started in the mid-1990s, offered a number of advantages for academic libraries and their users. However, escalating prices for these packages have become a serious issue casting doubts about the sustainability of the subscription-based model. At the moment, it appears there is no viable alternative other than pay-per-view method that is being tested at some libraries. Libraries' budget situation will remain a key factor that might change the situation. Open access started in the 2000s as a vehicle to eliminate barriers to publishing and distributing peer-reviewed scholarly journal articles. Open access publishing is witnessing two-digit growth annually. Open access articles now occupy close to 20% of two major citation databases: Scopus and Web of Science. Google Scholar service, debuted in late 2004, is now a popular tool for discovering and accessing scholarly articles from a vast selection of journals around the world. There is a call for taking Google Scholar seriously as a potential replacement of library databases amid concerns regarding the quality of journals indexed, limited search capabilities vis-$\grave{a}$-vis library databases, and monopoly of public goods. Escalating budget problems, rapid growth of open access publishing and the emergence of powerful free tool, such as Google Scholar, need to be taken seriously as these forces might bring disruptive changes to the existing subscription-based model of scholarly contents at academic libraries.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.4
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• pp.369-379
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• 2010

Zooplankton community structure and copepod production in Seomjin River estuary were investigated at 10 stations along the salinity gradients from May 2009 to February 2010. Total zooplankton taxa were identified to be 31 in the study area and seasonal average abundance of zooplankton was $4,151\;ind.{\cdot}m^{-3}$ during the study period. Zooplankton community was mainly composed of coastal species in dry season. However, brackish species dominated in upper or middle part of this estuary in flood season. This study showed that the growth rates of Acartia spp. and Paracalanus parvus s.l. measured from field experiments were regulated by the variations of Hater temperature and salinity; The annual copepod production estimated by dominant copepod species was $3.49\;g\;C{\cdot}m^{-2}yr^{-1}$, and the relatively high production value could be explained by the high phytoplankton standing stocks and the mass occurrence of coastal and brackish species with relation to various salinity gradients in Seomjin River estuary.

• Environmental and Resource Economics Review
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• v.18 no.2
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• pp.241-277
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• 2009

The purpose of this paper is to compare technical efficiencies and productivities without and with environmental constraints, and shadow prices of $SO_x$ in Korean and Chinese industries. The technical efficiencies without and with environment in Chinese manufacturing industries are higher than those in Korean manufacturing industries for 2000-2004. Most of individual Chinese manufacturing dominate those of Korean manufacturing in levels of technical efficiency. In terms of productivity changes excluding environmental constraints, the rates of annual growth in Korean and Chinese industries show 1.13 percent and 2.73 percent respectively. But Korean industry in productivity changes considering $SO_x$ reduction shows 2.41 percent, higher rate of growth than 1.58 percent of Chinese industry. In the shadow prices of $SO_x$, the reduction of an additional unit of $SO_x$ in the Korean manufacturing needs a decrease of 1.473 unit of output, while the shadow price of $SO_x$ in Chinese manufacturing is 0.0049, close to zero. Korean manufacturing should be specialized in higher sectors of technical efficiency and productivity and be also kept efficient in pollution abatement cost.

• Korean Journal of Crystallography
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• v.4 no.2
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• pp.74-85
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• 1993

Single crystals of LiNbO3 have found extensive application in electro-optic and nonlinear optic devices. However, laser-induced refartive index inhomogeneities, which have been labeled opical damage impose limits on device optical damage in LiNbO3 is imporved if more than 4.5 rml% MgO is added to the melt The laser damage thrueshold increased as much as 100 times better then that of undoped crystals. The MgO doped cystal has thus been urterlsiv81y studied since then. In the study, Mgo:LiNbOs(MLA) single crystals dopsd with 0, 2.5, 5.0, 7.5, 10.0 mol% MgO have been grown by the czocrualski technique. The metls were prepared in the platinum crluible and 15∼20mm diameter crystals were grown with a length of 20∼30mm in a resitance heater. The growth rate was 2.5mm/hr, the rotation speed 15rpn. Before sawing MLN single crystals were annealed for 24 hours under atmosphere at a temperature of 1080℃. After sawing, we have found an annual ring cross section of MNA crystals only in the direction of perpendicilar to the c-axis. Nonuniform dispusion of MgO was pointed out that the cuties of the state of oxide were strongly affected by oxygen partial pressure in.

• Spatial Information Research
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• v.23 no.5
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• pp.21-30
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• 2015

Korean government has promoted the projects of National Geographic Information Systems since 1995 and the utilization level of Korean National Spatial Data Infrastructure based on them has also developed. However, due to the limit to domestic market size and the legal regulation on prohibition of large sized companies' expansion into domestic spatial information markets, Korean spatial information markets are tied up in term of industrial competitiveness. To overcome those problems and evade the domestic red oceans, it is necessary to find new one in overseas' blue ocean markets. It is estimated that overseas spatial information market will be grown to 125 billion-dollar size and the annual growth rate of it will be reached to 10.5% until 2015. Thus, Asian spatial information market has a huge growth potential and it is newly rising blue oceans for Korea. Advanced countries such as Finland, Germany, Sweden, and Japan have already expanded their market size into the newly industrializing countries. To step with advanced countries, it is time to set up the new globalization strategy of Korean spatial information for expansion into newly industrializing markets. The purpose of this study is to analyze the SWOT of domestic spatial information, investigate the status on spatial information of Asian developing countries, and suggest the globalization strategy of Korean spatial information for expansion into them. The globalization strategy can be labelled as K-FBI composed of 4 domains such as Knowledge sharing platform, Frontier, Back to the basic, and Internalization. In near future, the establishment and performance of road map based on the strategy will be the milestone for Korean spatial information companies' advance into Asian developing countries.

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.161-171
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• 2003

The present study evaluated water quality variation, limiting nutrient, and sediment of a shallow eutrophic lake (Lake Ilgam) in the metropolitan area from 2000 to 2002. According to annual mean chl.a ($77.2{\pm}36.6\;{\mu}g/l) and TP ($66.6{\pm}20.5\;{\mu}g/l) concentration and trophic state index (>60), Lake llgam was in very eutrophic status. Both inorganic nitrogen ($NH_3-N$ and $NH_3-N$) and phosphorus (SRP) concentrations in the water column increased during winter and spring, but decreased during summer followed by the phytoplankton development. Evidence for phosphorus and nitrogen as being the potential limiting nutrients for phytoplankton growth was supported by the ratio of DIN/DIP (by mass) (${\sim}$835.8), TSI derivations analysis, and algal growth potential bioassay. Based on the results of TSI derivations, strong nutrient limitation by both N and P occurred from September to November when P content in sediment (114.6 mg P/kg) was relatively low compared with the summer. Sediment contained a large amount of nitrogen (TKN: 4,452${\pm}$283.0mg N/kg dry sediment). Phosphorus content in sediment (TP: 313${\pm}$155 mg P/kg) was relatively low with temporal change. P release rate (0.29${\pm}$0.02 mg $m^{-2}$ $day^{-1}$) was high under the aerobic condition at pH 9. These results indicate that the sediment could play an important role as a source of a limiting nutrient, and temporal change of P content in the sediment is closely related with water quality, especially algal biomass change in Lake llgam.

• Journal of Wetlands Research
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• v.15 no.3
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• pp.347-356
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• 2013

To provide the information for the wetland management considering the water treatment ability of macrophytes, the growth characteristics and primary production by reed (Phragmites australis) and cattail (Typha angustifolia), and the decomposition rate of organic matter produced were investigated in two sub-wetlands (Banweol and Donhwa wetlands) of the Sihwa Constructed Wetland (CW) with different chemistry of inflows. The shoot height of P. australis and Typha angustifolia began to increase in March, and reached its peaks in July and August (340cm and 320cm, respectively). The shoot density of P. australis ranging $100{\sim}170EA/m^2$ was higher than that of T. angustifolia (max. $78EA/m^2$). Standing biomass of P. australis ranged from $1,350{\sim}1,980gDM/m^2$, with maximal biomass in Banwol Upper Wetland. And it was larger in upper wetlands than lower wetlands. On the other hand standing biomass of T. angustifolia ($1,940gDM/m^2$) was similar to that of P. australis in Banwol Upper Wetland. Primary productivity of P. australis was in the order of Banwol Upper Wetland ($2,050gDM/m^2/yr$) > Donghwa Lower Wetland ($1,840gDM/m^2/yr$) > Banwol Lowerr Wetland ($1,570gDM/m^2/yr$) ${\fallingdotseq}$ Donghwa Lower Wetland ($1,540gDM/m^2/yr$), and that of T. angustifolia ($2,210gDM/m^2/yr$) was higher than P. australis. Annual production of organic matter produced by P. australis and T. angustifolia was 845 ton DM/yr (423 ton C/yr), and about 90% was comprised of that by P. australis. From the litter decomposition rate (k) (P. australis: leaf 0.0062/day, stem 0.0018/day; T. angustifolia: leaf 0.0031/day, stem 0.0018/day), leaf was rapid degraded compare to stem in both P. australis and T. angustifolia. The litter decomposition rate of leaf was two times rapid P. australis than T. angustifolia, whereas that of stem was same in both. Annual litter decomposition amount of P. australis than T. angustifolia was 285 ton C/yr(67.3% of organic matter produced by macrophytes), indicating that 32.7% of organic matter produced by macrophytes is accumulated in the Sihwa CW.