• Journal of Service Research and Studies
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• v.1 no.1
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• pp.29-48
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• 2011

Recently not only industry but also academy have shown an intense interest in social networking service. However, reckless imitation will not guarantee the successful eco-system of social networking service without rich understanding of growth driver and business model. Hence, this study aims at analyzing open platform strategy and business model conducted by a representative social networking service provider in order to provide platform operator, network operator, and portal provider with meaningful implications. Advertisers may pay great attention to social networking service because it has strong ability to provide users with spontaneous motivation to manage and update their profile, and these valuable information can be utilized for providing personalized advertisement on social networking service. As a result, one side of consumers in two side market, advertisers, tend to pay more expenditure to place advertisements. In addition, the open platform adopted by social networking service providers causes pro-sumers to participate in the eco-system, and thereby the explosive quantitative growth is realized. The fact of that this open social networking service can invade other web service area via an unified platform indicates that it may expand its service scope into a wide variety of web service areas. Hence, domestic portal services providers and network providers should consider social networking service not as one of new web services but as an disruptive service platform. Corresponding to the emergence of social networking service, especially if their business area is related to display advertising market, they should seek a way to provide social networking service access users's newly updated information and develop innovative media technologies to enter context awareness ads market.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.4
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• pp.246-251
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• 2017

Crop models have been used to predict a heading date for efficient management of fertilizer application. Recently, the ORYZA (v3) model was developed to improve the ORYZA2000 model, which has been used for simulation of rice growth in Korea. Still, little effort has been made to assess applicability of the ORYZA (v3) model to rice farms in Korea. The objective of this study was to evaluate reliability of heading dates predicted using the the ORYZA (v3) model, which would indicate applicability of the model to a decision support system for fertilizer application. Field experiments were conducted from 2015-2016 at the Rural Development Administration (RDA) to obtain rice phenology data. Shindongjin cultivar which is mid-late maturity type was grown under a conventional fertilizer management, e.g., application of fertilizer at the rate of 11 Kg N/10a. Another set of heading dates was obtained from annual reports at experiment farms operated by the National Institute of Crop Science and Agricultural Technology Centers in each province. The input files for the ORYZA (v3) model were prepared using weather and soil data collected from the Korean Meteorology Administration (KMA) and the Korean Soil Information System, respectively. Input parameters for crop management, e.g., transplanting date and planting density, were set to represent management used for the field experiment. The ORYZA (v3) model predicted heading date within 1 day for two seasons. The crop model also had a relatively small error in prediction of heading date for three ecotypes of rice cultivars at experiment farms where weather input data were obtained from a near-by weather station. Those results suggested that the ORYZA (v3) model would be useful for development of a decision support system for fertilizer application when reliable input data for weather variables become available.

• Korean Journal of Breeding Science
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• v.41 no.1
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• pp.25-31
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• 2009

This study was conducted in order to breed Japonica salt tolerant rice and select salinity tolerant lines by establishing reliable and practical method of screening voluminous materials. Salinized nutrient solution by adding NaCl was effective compared with the salinized nutrient solution by adding 0.3%, 0.6% and 0.7% of diluted sea water. There was no different visual score of salinity injury between salinization using tap water and distilled water. Seedling salinity tolerant lines between region and order by year were showed very stable and reproducible results, 3~4.2 of visual score at Gyehwado-substation and International Rice Research Institute (IRRI, Philippines) in 2002, 2003 and 2004. Heading date of 6 selected seedling salt tolerant lines showed a range of 16. Aug.~21. Aug. and delayed 2~6 days than that of Donjinbyeo. Percentage of ripened grain and yield of milled rice in 6 lines was lower, 52.2~14.7% and 50~5%, respectively than those of Donjinbyeo.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.305-309
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• 1983

To know the effect of desaltation in the reclaimed tidal fields on the succession of vegetation and on the root hair formation of paddy rice, reclaimed fields in Kang Hwa Island, Nam-Yang Bay and Ke-Hwa Island were investigated during summer crop season in 1982. The obtained results can be summarized as followings. l) In the highly salty and water logged areas of reclaimed tidal fields, the first dominating species of higher plant were observed to be Salicornia herbacea L. and Suaeda japonica Makino. With the continued desaltation, Chemopodium virgatum Thumb. occurred in the vegetation. After this transition, the dominating species were composed of Scirpus maitimus L. and Phragmites communis Trin. At the S. maitimus and P. communis dominating salinity level, rice cultivation was safe from the salt damage. 2) In the water logged area, Artemisia capillaria Thunb. and Aster tripolium L. took the place of dominating species after S. herbacea and S. japonica. At this salinity level, graminaceous weeds began to immigrate. 3) In dry areas, Suaeda asparagoides Makino and Suaeda maritima were the first appearing dominant species. Atriplex subcordata Kitakawa was also observed in sucy dry areas, but colony formation was not observed. 4) Plants immigrated slowly into dry areas from the already vegetated water logged areas with the continuation of desaltation. 5) The high soil salinity level affected the root hair formation of rice by reducing both the rate of root hair formation and the length of root hairs.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.4
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• pp.241-248
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• 1993

An experiment was conducted in 1990~1991 to study the effects of various soil amelioration on the soil productivity and machine workability at tidal land paddy field of Kyewhado Substation, Homam Crop Experiment Station. The soil, Munpo Series(fine sandy loam, Typic Fluvaquents) was treated with gipsum, rice straw, rice straw compost and foreign soil(at 20cm depth) after deep ploughing. The results are surmerized as follows. 1. Sand and clay were slightly increased, while silt was slightly decreased in the rice straw and compost plots. The soil texture was changed from loam to sand loam by the addition of foreign soil 2. Soil bulk density and porosity was decreased in the rice straw, compost and foreign soil addition plots. 3. Cone penetration resistance was $12.5kg/cm^2$ at 10cm of soil depth before experiment and $12.5kg/cm^2$ at 20cm of soil depth after experiment except control, and the root zone was expended down to 20cm. 4. Soil salt content before experiment was 0.46 and 0.48% for surface soil(10cm) and subsoil(20cm), respectively ; The salt content of ameliorated plot was 0.26~0.32% and 0.16~0.31%, respectively, indicating good leaching of soil salt by the soil improvements. 5. The yields of rice in different treatments were in the order of the foreign soil addition > compost > gypsum > rice straw > control.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.764-769
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• 2010

We investigated influence of continious application of gypsum (G: $CaSO_4{\cdot}2H_2O$), popped rice hulls (H) and zeolite (Z) on soil aggregation of reclaimed sandy loam soils. The application rates amended to fine sandy loam from reclaimed soils at Kyehwado were varied as follows:1550 (G1), 3100 (G2), 6200 (G3), 1000 (H1), 2000 (H2), 3000 (H3), and 200 (HZ1), 400 (HZ2) and 800 (HZ3) added to 1500(H) kg $10a^{-1}$, respectively. Soil aggregates were analyzed for 60, 90 and 120 days after treatments (DAT). At 60 DAT, The amount of aggregate from soil samples treated with gypsum was slightly increased with G1 while the aggregation was decreased by 4.66% for G3 for soil aggregates than thar of control. The treatments of H or HZ were effective in soil aggregation. The effect of treatment was in the order of H > HZ > G. At 90 DAT, increasing amount of gypsum attributed to decrease in soil aggregates. Therefore, we could conclude that suitable amounts of gypsum for soil aggregation in fine sandy loam might be 1550 kg $10a^{-1}$ or less. H1 increased aggregation by 7% for aggregate size between 1.0 and 2.0 mm. HZ1 was most effective in aggregation by 52.78% among the treatments while H2 and HZ3 51.50% and 48.51% at 120 DAT, respectively. As a result, we found that the effect of the treatment for soil amendments was in order of H > HZ > G.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.579-585
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• 2014

This study was conducted to investigate liquid pig manure (LPM) application rates on the growth characteristics, yield, and feed value of whole crop barley in Yeongsangang and Saemangeum reclaimed tidal land. Electronic conductivity (EC), organic matter (OM), and available phosphate (Av. $P_2O_5$) increased in chemical properties of Yeongsangang and Saemangeum soil as raising LPM application level. As increasing LPM application level, exchangeable $Na^+$ significantly increased in Yeongsangang, while exchangeable $K^+$ significantly increased in Saemangeum. Plant height was not significantly different from LPM 100% to LPM 200% in Yeongsangang and in Saemangeum. Dry matter yield of whole crop barley increased steadily, but crop yield of LPM 200% in Yeongsangang ($10.5ton\;ha^{-1}$) was as much as that of LPM 150% ($10.0ton\;ha^{-1}$). Yield of LPM 200% ($11.2ton\;ha^{-1}$) in Saemangeum was similar to that of LPM 150% ($10.5ton\;ha^{-1}$). Crude protein (CP) increased depending on LPM application level, but total digestible nutrients (TDN) increased regardless of LPM application level. LPM 200% was the highest in TDN yield (Yeongsangang: $7.4ton\;ha^{-1}$, Saemangeum: $6.9ton\;ha^{-1}$), but there was no statistical difference between LPM 150% (Yeongsangang: $6.9ton\;ha^{-1}$, Saemangeum: $6.6ton\;ha^{-1}$) and LPM 200%. From the results described above, optimum rate of LPM for cultivating whole crop barley is considered 100% in Yeongsangang reclaimed tidal land and 150% in Saemangeum reclaimed tidal land, showing that the effect of LPM application is better in Segmentation than that in Yeongsangang for yield of whole crop barley.

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.1-9
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• 2012

This study was conducted to survey vegetation changes and soil characteristics in Saemangeum new reclaimed tidal land. Soil salinity in border area to tidal land was 22.3 dS $m^{-1}$ but showed 1.1~3.44 dS $m^{-1}$ over the distance of 2 km from border line. The vascular plants in survey sites were recorded as total 26 taxa in 6 families. The frequency of species appearance of Aster tripolium, A. subulatus var. sandwicensis were highest by 61.5 and that of Phragmites communis, Puccinellia nipponica were 53.8. The almost vegetations occurred in the patch which range of soil salinity 14 dS $m^{-1}$ were halophytes as Salicornia europaea, Suaeda asparagoides, S. japonica. As lowed soil salinity as 6.7 dS $m^{-1}$, mixed vegetation of halophytes with P. communis, P. nipponica, Carex pumila were occurred. Dominant species in the range of 3.0 dS $m^{-1}$ area were A. subulatus var. sandwicensis, P. communis, Echinochloa spp., Zoysia sinica and Conyza canadensis. Biomass production was the highest in the area of dominant vegetation with P. communis, and mixed zone with P. communis and Aeschynomene indica are followed. The correlation between vegetation biomass and soil salinity, soil pH and dominance index of vegetation were negative. But that of vegetation biomass and soil organic content were positive.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.1
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• pp.34-43
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• 1990

Six commerical rice varieties were cultivated and harvested at different locations in 1987 and 1988 to clarify the degree of locational variations. of several characteristics related to rice grain quality using the rice samples harvested from 8 to 20 locations for a variety each year. Locational variations of percent brown rice, percent milled rice, 1000-grain weight and amylose content were small, but whole grain rate, alkali digestibility, gel consistency, percent white-center and white-belly grain, degree of chalkiness and degree of translucency showed larger variations between locations. The degree of locational variation of sensory evaluation score for eating quality of cooked rice were varied from small to large along with rice variety used and year cultivated. Texture palatability index and stickiness of cooked rice among rheogram characteristics showed larger locational variations, but cohesiveness and springiness showed smaller variations between locations. Set back, break down and maximum viscosity showed larger locational variations among amylogram characteristics of rice flour. Special attention was given to a cultivated location, Anseong, because rice samples harvested at Anseong showed lower percent white-center and white-belly grain, and low set back and high break down in Chucheongbyeo, lower percent white-center and white-belly grain, higher texture palatability index and viscousness/hardness ratio, and low set back and high break down in Dongjinbyeo, higher texture palatability index, and low set back and high break down in Yongmunbyeo, lower percent white-center and white-belly grain in Sangpungbyeo, and low set back and high break down in Samkangbyeo. No other locations in this study produced rice samples showing wide acceptable quality-related characteristics except Anseong.

• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.25-31
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• 2009

The effect of application of gypsum (G), popped rice hulls (PRH), and zeolite (Z) in exchangeable cations concentrations of reclaimed tideland soil in Kyehwado was investigated for 3 years from 2004 to 2006 in a pot experiment with bermuda grass (Cynodon dactylon). Treatments with three soil conditioner and with three applications were established with three replications; G1 (1,550 kg $10a^{-1}$), G2 (3,100), and G3 (6,200) for gypsum, H1 (1,000), H2 (2,000), and H3 (3,000) for PRH, and HZ1 (200), HZ2 (400), and HZ3 (800) for co-application of zeolite with PRH at the 1,500 kg $10a^{-1}$. At 60, 90, 120 days after treatment (DAT), exchangeable cations ($K^+$, $Na^+$, $Mg^{2+}$, and $Ca^{2+}$) were analyzed Gypsum application significantly decreased $k^+$, $Na^+$, $Mg^{2+}$ in the soil probably due to exchange and subsequent leaching of these cations by $Ca^{2+}$ from the gypsum applied. Overall, $K^+$ concentration was gradually decreased by continuous application of soil conditioners and was in the order of 2004>2005>2006 regardless of the kinds and application rate of soil conditioners. Comparing $K^+$ concentrations among the soil conditioners in the same year, its concentration was in the order of gypsum$Na^+$ concentration; i.e. $Na^+$ concentration was in the order of gypsum$\ll$PRH$Mg^{2+}$ also showed a similar pattern to $Na^+$. Gypsum application significantly increased $Ca^{2+}$ concentration and in the gypsum treated soil $Ca^{2+}$ concentration increased with years.