• Geophysics and Geophysical Exploration
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• v.1 no.2
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• pp.87-91
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• 1998

Geophysical survey techniques, such as electromagnetic(EM), GPR, and electrical method, have been tested in the landfill area to evaluate the applicability of these methods to soil contamination measurement. The EM method has proven to be excellent on mapping the areal distribution of contaminants and the migration path for leachate. Since the field operation of EM technique is simple as well as fast, we think the EM method must be the first choice for these purposes. Electrical survey techniques have proven to be very effective on mapping sectional distribution of contaminants. Generally, the GPR method is very good on high resolution survey of shallow depth, and field data acquisition is simple, too. But the resistivity method gives better information on deep area, for example, deeper than the depth of 20 m.

• Journal of Soil and Groundwater Environment
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• v.13 no.3
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• pp.37-44
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• 2008

Soil ecology has important roles in global ecosystems. However, soil ecological quality information is being ignored when assessing ecological impact of construction actions. And methods for classifying and assessing soil ecological quality have been very little established in comparison to those for animal and plant ecosystems. In this study, it was examined whether soil ecological quality information has influence on determining an eco-friendly route for a road construction project. For this, sensitivity analysis was systematically performed by varying the relative significance (weights) of soil ecological quality information among natural environmental and ecological factors. When the weight of soil ecological quality was greater than just 14%, the soil ecological quality information significantly influenced the determination of the eco-friendly routes for a specific road construction project. This demonstrates that soil ecological quality information has to be considered for more reliable environmental impact assessment, and also supports the validity of use of soil ecological quality information and its mapping technique in planning and siting of eco-friendly construction projects.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.343-348
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• 1984

Variation of soil properties within mapping unit of lava plain soils was statistically summarized. Properties such as particle size distribution, moisture retention, color, pH, and CEC are relatively unaffected by soil management while Na, K, base saturation, and available $P_2O_5$ most affected by management. These soils were correctly classified with regard to order at 66.5, to greatgroup at 56.0, and to series at 43.8%. CV values greater than 90% could be symptomatic of skew distribution. Distributions of sand content and some chemical properties were log-normal.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.684-695
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• 2010

Geographic information system (GIS) is being increasingly used for decision making, planning and agricultural environment management because of its analytical capacity. GIS and remote sensing have been combined with environmental models for many agricultural applications on monitoring of soils, agricultural water quality, microbial activity, vegetation and aquatic insect distribution. This paper introduce principles, vegetation indices, spatial data structure, spatial analysis of GIS and remote sensing in agricultural applications including terrain analysis, soil erosion, and runoff potential. National Academy of Agricultural Science (NAAS), Rural Development Administration (RDA) has a spatial database of agricultural soils, surface and underground water, weeds, aquatic insect, and climate data, and established a web-GIS system providing spatial and temporal variability of agricultural environment information since 2007. GIS-based interactive mapping system would encourage researchers and students to widely utilize spatial information on their studies with regard to agricultural and environmental problem solving combined with other national GIS database. GIS and remote sensing will play an important role to support and make decisions from a national level of conservation and protection to a farm level of management practice in the near future.

• Geomechanics and Engineering
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• v.11 no.3
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• pp.325-343
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• 2016

A total stress-based bounding surface model is developed to predict the undrained behaviour of saturated soft clays under cyclic loads based on the anisotropic hardening modulus field and bounding-surface theories. A new hardening rule is developed based on a new interpolation function of the hardening modulus that has simple mathematic expression and fewer model parameters. The evolution of hardening modulus field is described in the deviatoric stress space. It is assumed that the stress reverse points are the mapping centre points and the mapping centre moves with the variation of loading and unloading paths to describe the cyclic stress-strain hysteresis curve. In addition, by introducing a model parameter that reflects the accumulation rate and level of shear strain to the interpolation function, the cyclic shakedown and failure behaviour of soil elements with different combinations of initial and cyclic stresses can be captured. The methods to determine the model parameters using cyclic triaxial compression tests are also studied. Finally, the cyclic triaxial extension and torsional shear tests are performed. By comparing the predictions with the test results, the model can be used to describe undrained cyclic stress-strain responses of elements with different stress states for the tested clays.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• v.6 no.1
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• pp.22-29
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• 2003

This research aims at investigation of accuracy potential of RTK(Real-Time Kinematic) GPS in combination with Echo Sounder(E/S) for the coastal mapping. Apart from this purpose, the accuracy of ambiguity resolution with the OTF(On The Fly) method was tested with respect to the initialization time. The result shows that the accuracy is better than 1cm with 5-minute initialization in the distance of 10km baseline. The seaside topography was measured by the RTK GPS only, on the other hand the seafloor topography was surveyed in combination of RTK GPS and E/S. Comparing to the volume of seaside measured by RTK GPS and digital topographical map, the difference of only 2% was achieved. This indicates that the coastal mapping. As a result, it has been revealed that every possible noise in surveying could be corrected and the accuracy could be improved. The accuracy of GPS data acquired in real time was as good as that acquired by post processing. It is expected that it will be useful for the analysis of coastal geographic characteristics because DTM(Digital Terrain Model) can be also constructed for the harbor reclamation, the dredging, and the variation of soil movement in a river.

• Journal of Ocean Engineering and Technology
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• v.17 no.3 s.52
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• pp.13-20
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• 2003

This research aims at investigation of accuracy potential of RTK(Real-Time Kinematic) GPS in combination with Echo Sounder(E/S) for the coastal mapping. Apart from this purpose, the accuracy of ambiguity resolution with the OTF(On The Fly) method was tested with respect to the initialization time. The result shows that the accuracy is better than 1cm with 5-minute initialization in the distance of 10km baseline. The seaside topography was measured by the RTK GPS only, on the other hand the seafloor topography was surveyed in combination of RTK GPS and E/S. Comparing to the volume of seaside measured by RTK GPS and digital topographical map, the difference of only $2\%$ was achieved. This indicates that the coastal mapping. As a result, it has been revealed that every possible noise in surveying could be corrected and the accuracy could be improved. The accuracy of GPS data acquired in real time was as good as that acquired by post processing. It is expected that it will be useful for the analysis of coastal geographic characteristics because DTM(Digital Terrain Model) can be also constructed for the harbor reclamation, the dredging, and the variation of soil movement in a river.

• Journal of the Korean Geosynthetics Society
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• v.5 no.2
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• pp.9-15
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• 2006

The numerical analysis program using artificial displacement method is developed to analyze the deformation behavior of excavated behind ground of retention wall. The elasto-plastic model suggested by Drucker-Prager was used to represent soil behavior and the model's solution was obtained from the return mapping method. To validate of the program, the predicted results by the numerical analysis and the measured results by a field test are compared. The results of numerical analysis showed good agreement with the measured results in field and theoretical values.

• The Plant Pathology Journal
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• v.17 no.2
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• pp.67-70
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• 2001

Medicago truncatula is a diploid legume plant related to the forage crop alfalfa. Recently, it has been chosen as a model species for genomic studies due to its small genome, self-fertility, short generation time, and high transformation efficiency. M. truncatula engages in symbiosis with nitrogen-fixing soil bacterium Rhizobium meliloti. M. truncatula mutants that are defective in nodulation and developmental processes have been generated. Some of these mutants exhibited altered phenotypes in symbiotic responses such as root hair deformation, expression of nodulin genes, and calcium spiking. Thus, the genes controlling these traits are likely to encode functions that are required for Nod-factor signal transduction pathways. To facilitate genome analysis and map-based cloning of symbiotic genes, a bacterial artificial chromosome library was constructed. An efficient polymerase chain reaction-based screening of the library was devised to fasten physical mapping of specific genomic regions. As a genomics approach, comparative mapping revealed high levels of macro- and microsynteny between M. truncatula and other legume genomes. Expressed sequence tags and microarray profiles reflecting the genetic and biochemical events associated with the development and environmental interactions of M. truncatula are assembled in the databases. Together, these genomics programs will help enrich our understanding of the legume biology.

• Journal of The Geomorphological Association of Korea
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• v.23 no.2
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• pp.109-125
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• 2016

This study aims to identify the landslide susceptible zones of Boeun area and provide reliable landslide susceptibility maps by applying different modeling methods. Aerial photographs and field survey on the Boeun area identified landslide inventory map that consists of 388 landslide locations. A total ofseven landslide causative factors (elevation, slope angle, slope aspect, geology, soil, forest and land-use) were extracted from the database and then converted into raster. Landslide causative factors were provided to investigate about the spatial relationship between each factor and landslide occurrence by using fuzzy set and logistic regression model. Fuzzy membership value and logistic regression coefficient were employed to determine each factor's rating for landslide susceptibility mapping. Then, the landslide susceptibility maps were compared and validated by cross validation technique. In the cross validation process, 50% of observed landslides were selected randomly by Excel and two success rate curves (SRC) were generated for each landslide susceptibility map. The result demonstrates the 84.34% and 83.29% accuracy ratio for logistic regression model and fuzzy set model respectively. It means that both models were very reliable and reasonable methods for landslide susceptibility analysis.