• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.1
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• pp.57-70
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• 2017

In this study, we evaluated daily root zone soil moisture dynamics and agricultural drought using a near-surface soil moisture data assimilation scheme with Soil Moisture Active & Passive (SMAP, $3km{\times}3km$) soil moisture footprints under different hydro-climate conditions. Satellite-based LANDSAT and MODIS image footprints were converted to spatially-distributed soil moisture estimates based on the regression model, and the converted soil moisture distributions were used for assessing uncertainties and applicability of SMAP data at fields. In order to overcome drawbacks of the discontinuity of SMAP data at the spatio-temporal scales, the data assimilation was applied to SMAP for estimating daily soil moisture dynamics at the spatial domain. Then, daily soil moisture values were used to estimate weekly agricultural drought based on the Soil Moisture Deficit Index (SMDI). The Yongdam-dam and Soyan river-dam watersheds were selected for validating our proposed approach. As a results, the MODIS/SMAP soil moisture values were relatively overestimated compared to those of the TDR-based measurements and LANDSAT data. When we applied the data assimilation scheme to SMAP, uncertainties were highly reduced compared to the TDR measurements. The estimated daily root zone soil moisture dynamics and agricultural drought from SMAP showed the variability at the sptio-temporal scales indicating that soil moisture values are influenced by not only the precipitation, but also the land surface characteristics. These findings can be useful for establishing efficient water management plans in hydrology and agricultural drought.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.4
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• pp.171-180
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• 2014

Since the execution of structural design by professional structural engineers is not mandatory for small-size buildings in Korea, structural design is conducted by architects or contractors resulting in concern about the seismic safety of the buildings. Therefore, the Korean Structural Engineers Association proposed dedicated structural design criteria in 2012. The criteria were developed based on a deterministic approach in which the structural members are designed only with information of story and span length of the buildings and without structural analyses. However, due to the short time devoted to their development, these criteria miss satisfactory basis and do not deal with structural walls popularly used in Korea. Accordingly, the Ministry of Land, Infrastructure and Transport launched a research on the 'development of structural performance enhancement technologies for small-size buildings against earthquakes and climate changes'.. As part of this research, this paper intends to establish direction for the preparation of deterministic structural design guidelines for seismic safety of domestic small-size reinforced concrete buildings. To that goal, a typical plan of these buildings is selected considering frames only and frames plus walls, and then design is conducted by changing the number of stories and span length. Next, the seismic performance is analyzed by nonlinear static pushover analysis. The results show that the structural design guidelines should be developed by classifying frames only and frames plus walls. The size and reinforcement of structural elements should be provided in the middle level of the current Korean Building Code and criteria for small buildings by considering story and span length for buildings with frames only, and determined by considering the shape and location of walls and the story and span length as well for buildings with frames plus walls. It is recommended that the design of walls should be conducted by reducing the amount of walls along with symmetrically located walls.

• Journal of Ecology and Environment
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• v.41 no.2
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• pp.34-44
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• 2017

Background: Monitoring terrestrial vegetation cover condition is important to evaluate its current condition and to identify potential vulnerabilities. Due to simplicity and low cost, point intercept method has been widely used in evaluating grassland surface and quantifying cover conditions. Field-based digital photography method is gaining popularity for the purpose of cover estimate, as it can reduce field time and enable additional analysis in the future. However, the caveats and uncertainty among field-based vegetation cover estimation methods is not well known, especially across a wide range of cover conditions. We compared cover estimates from point intercept and digital photography methods with varying sampling intensities (25, 49, and 100 points within an image), across 61 transects in typical steppe, forest steppe, and desert steppe in central Mongolia. We classified three photosynthetic groups of cover important to grassland ecosystem functioning: photosynthetic vegetation, non-photosynthetic vegetation, and bare soil. We also acquired normalized difference vegetation index from satellite image comparison with the field-based cover. Results: Photosynthetic vegetation estimates by point intercept method were correlated with normalized difference vegetation index, with improvement when non-photosynthetic vegetation was combined. For digital photography method, photosynthetic and non-photosynthetic vegetation estimates showed no correlation with normalized difference vegetation index, but combining of both showed moderate and significant correlation, which slightly increased with greater sampling intensity. Conclusions: Results imply that varying greenness is playing an important role in classification accuracy confusion. We suggest adopting measures to reduce observer bias and better distinguishing greenness levels in combination with multispectral indices to improve estimates on dry matter.

• Journal of Forest and Environmental Science
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• v.29 no.2
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• pp.147-156
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• 2013

Multiple use forestry is capable of generating income for forest based communities through Non-Timber forest products (NTFPs) which provide food, medicine, materials for domestic use and cash income for communities adjoining forest areas in developing countries. This study evaluates the economics of producing ginger rhizomes under teak canopy in a multiple land use system during 2007 and 2008 in even aged teak plantations in Ibadan and Ife, Nigeria. Twelve $6m^2$ sample plots were randomly selected in Completely Randomized Block Design within and outside the plantation. Average ginger rhizome of (50-60 g) were planted on the slightly tilled soil. NPK 15:15:15 was applied at 180 kg/ha on a split unit dose. ANOVA, Profitability, Benefit-Cost (B/C) ratio were used to analyze data. Results showed no significant differences between sites in ginger rhizome yield, (0.089 and 0.718, ${\rho}{\leq}0.05$) in 2007 and 2008 respectively. Average yield were higher outside teak canopy in both sites and treatments, (Ibadan -40.05 g>32.9 g, Ife -67.6 g>25.2 g and Ibadan -41.3 g>31.5 g, Ife -66.8 g>25.0 g) with and without NPK respectively. NPK had no effect on yields within teak plantation, (Ibadan -31.5<32.9 g, Ife -25 g<25.2 g). Ginger rhizome production was viable financially without inorganic fertilizer during second cropping season within and outside plantation (B/C=1.02, 1.09) respectively. Ginger could be raised profitably under teak canopy, however, studies on insolation requirement of ginger under teak canopy and other tree plantations are recommended.

• Journal of Ecology and Environment
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• v.30 no.2
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• pp.121-126
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• 2007

We monitored gold-spotted pond frog (Rana chosenica) populations near the Korea National University of Education in Chungbuk, Korea, from 19 May to 8 August, 2006 to examine the spatial distribution of populations in local areas and to investigate patterns of migration of adult gold-spotted pond frogs from terrestrial hibernation sites to breeding sites, We captured individuals from the largest population using a drift fence with 22 pitfall traps surrounding the breeding site. A total of 22 individuals (19 males and 3 females) were captured between 23 May and 15 June. No peak in breeding migration was detected, but the onset of the breeding migration may correspond with increased humidity. Male body weights were negatively correlated with sampling dates. Seven of 22 individuals were captured at the 4th pitfall trap, which was placed between two culverts. The capture rate per pitfall trap was higher in traps close to the rice field banks (1.44, traps $1{\sim}9$) than in traps facing hilly land (0.33, traps $13{\sim}18$). Comparative data from the Korean frog (Rana coreana), a sympatric species in the study area, were also collected and compared with those of the gold-spotted pond frog.

• Journal of Microbiology and Biotechnology
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• v.22 no.7
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• pp.883-888
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• 2012

The efficacy of cowdung, Bangladesh Institute of Nuclear Agriculture (BINA)-biofertilizer, and Bangladesh Agricultural University (BAU)-biofungicide, alone or in combination, was evaluated for controlling foot rot disease of lentil. The results exhibited that BINA-biofertilizer and BAU-biofungicide (peat soil-based Rhizobium leguminosarum and black gram bran-based Trichoderma harzianum) are compatible and have combined effects in controlling the pathogenic fungi Fusarium oxysporum and Sclerotium rolfsii, which cause the root rot of lentil. Cowdung mixing with soil (at 5 t/ha) during final land preparation and seed coating with BINA-biofertilizer and BAU-biofungicide (at 2.5% of seed weight) before sowing recorded 81.50% field emergence of lentil, which showed up to 19.85% higher field emergence over the control. Post-emergence deaths of plants due to foot rot disease were significantly reduced after combined seed treatment with BINA-biofertilizer and BAU-biofungicide. Among the treatments used, only BAU-biofungicide as the seed treating agent resulted in higher plant stand (84.82%). Use of BINA-biofertilizer and BAU-biofungicide as seed treating biocontrol agents and application of cowdung in the soil as an organic source of nutrient resulted in higher shoot and root lengths, and dry shoot and root weights of lentil. BINA-biofertilizer significantly increased the number of nodules per plant and nodules weight of lentil. Seeds treating with BAU-biofungicide and BINA-biofertilizer and soil amendment with cowdung increased the biomass production of lentil up to 75.56% over the control.

• Korean Journal of Remote Sensing
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• v.22 no.2
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• pp.153-174
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• 2006

The purpose of this paper is to establish the category of SAR(Synthetic Aperture Radar) systems, technologies and application fields, thus to provide the world-wide trend in SAR research and development activities by analysing SAR-related journal papers. This paper presents an analysis result of SAR-related journal papers published from the late 1960s to early 2005. Abstracts and indices of 2665 peer-reviewed, English journal papers published in 243 journals were collected from the Cambridge Scientific Abstracts and classified into the categories according to the system, technique, and application field. Statistics on each category were provided so that one can understand the historical and on-going development in SAR systems, techniques, and a variety of application fields such as land, ocean, cryosphere and atmosphere. This statistical analysis data would be a valuable guideline to establish a future SAR system application and satellite manoeuvering policy in Korea.

• Asian Journal of Turfgrass Science
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• v.4 no.1
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• pp.42-48
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• 1990

Experiments were conducted to investigate the soil freezing depth and pattern with freezing measuring instruments during 1988-l989 winter season in Kangwon province. Freezing measuring instrument was made with acrylic pipes which were consisted of inner and outer parts. Inner pipe was filled with 0.01 % methylene blue solution and rubber hose to protect pipe breakdown by solution freezing. Freezing measurements were carried out by observing discoloration of methylene blue solution. Moisture content of evergreen trees and ground cover plants was also examined in the winter season. The observed results are as follows: 1.In the land of I OOM above sea level, soil freezing depth became deeper as the sum of Accumulated degree-days of temperature below 0˚C(0˚C . day) increased: Soil freezing depth was 30-40cm at l00˚C, 42-43cm at 150˚C, and 47cm at 200˚C day 2.Soil freezing with vinyl mulching was less developed by l3cm at l00˚C with sum of subzero temperature, by l7cm at 200˚C than that of the bare ground. Soil of rich hulls mulching with 4Ocm was not frozen until soil freezing at the bare ground was developed to 25cm depth. 3.Cashmeron mulching was more effective than felt mulching in the heat insulation of soil. 4.Thawing of soil was done from the lowest part of the frozen in the ground to upward in the beginning and after that it was done from the surface of frozen soil to downward. Finally thawing was completed at the middle of frozen soil.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.773-778
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• 2011

Long-term continuous application of livestock by-products to agricultural land may adversely affect the soil characteristics and the crop yield. Five year term study from 2007 was carried out to assess the effects of repeated application of low-concentration swine slurry on soil chemical properties including phosphate and heavy metal contents and yield of tomato (Lycopersicon esculentum) and cucumber (Cucumis sativus L.) in a greenhouse. Treatments were conventional chemical fertilizers and three application rates of low-concentration swine slurry (Slurry composting and biofiltration, SCB): 50%, 100%, and 200% of recommended nitrogen fertilization. For swine slurry treatment of 50% nitrogen, deficient nitrogen was supplemented with urea fertilizer. The soil phosphorus and heavy metal contents after five year continuous application of swine slurry were not significantly higher than those of chemical fertilizer use. Repeated application of the swine slurry alone for five years resulted in relatively high soil exchangeable potassium and sodium compared with chemical fertilizer treatment. Contents of heavy metals in leaves of tomato and cucumber did not show significant difference among treatments. Yields of the crops for the swine slurry were not significantly different from that of chemical fertilizer. The results imply that continuous application of the swine slurry may not influence levels of soil phosphate and trace elements in greenhouse soils but could accumulate potassium and sodium in the soil.

• Journal of Forest and Environmental Science
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• v.27 no.2
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• pp.81-91
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• 2011

An exploratory study was conducted in Gopalganj, a southern district of Bangladesh to explore the role of wild date palm (Phoenix sylvestris Roxb.) husbandry in the rural economy. A total of 36 households in the study area were interviewed using a semi-structured questionnaire. A multistage sampling method with 10% intensity and a semi-structured questionnaire were used for the study. Based on the land holding capacity of the households, the farmers were categorized into five groups as landless, marginal, small, medium, and large. The date palm was distributed over seven different habitats of which roadside support the highest value (31%) followed by agricultural field and orchard (25% each). Though the large category farmers own most of the palms (43%), a considerable portion (562 individuals out of 1980) of it is managed by the landless farmers, who earn a substantial livelihood from the palms. The farmers manage the palm mainly for juice production; juice is either used fresh as drink or after some sort of processing as molasses and/or alcoholic beverage. Date palm husbandry contributes 32,601 Tk., 21,107 Tk., 20,626 Tk., 29,574 Tk. and 35,335 Tk. respectively to the five group seasonally and 50,980 Tk., 77,556 Tk., 90,208 Tk., 112,560 Tk., 140,675 Tk. respectively annually (1 US$ = 70 Tk.). Date palm trees contribute 65.48% of mean annual income to landless farmers followed by 27.21% to marginal farmers. However the poor marketing system result in decreasing the annual return from palm trees. Palm husbandry could be a promising source of rural incomes in Bangladesh if the farmers' traditional management knowledge was linked to more scientific management practices.