• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.383-386
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• 2006

Subsurface temperature is affected by heat advection due to groundwater advection. Temperature-depth profile can be perturbed especially when there are significant vertical groundwater flux caused by external force such as injection or extraction. This research is to clarify the change of subsurface temperature distribution when the 40m x l0m sandy aquifer is stimulated by two different vertical flux($case1:\;{\pm}10^{-5}m^3/s,\;case2:\;{\pm}4{\times}10^{-5}m^3/s$) using a program called HydroGeoSphere. The resulting temperature distribution contour map shows pumping causes vertical attraction of water from deeper and warmer place which result in rising up isotherm. Additionally more injection/extraction rate, more vertical groundwater flux leads to faster Increase in temperature near the pumping well.

• Journal of the Korean GEO-environmental Society
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• v.14 no.1
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• pp.33-42
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• 2013

In this paper, a series of monotonic undrained shear tests were carried out on four kinds of sand-fine mixtures with various fines content. Two kinds of sands (Silica sand V3, V6) and fines (Iwakuni natural clay, Tottori silt) were mixed together in various proportions, while paying attention to the void ratio expressed in terms of sand structure $(F_c{\leq}F_{cth})$. The undrained shear strength of mixtures below the threshold fines content was observed so that as the plastic fines content increases, maximum deviator stress ratio decrease for dense samples while an increase is noted for loose samples. For non-plastic fines, the increase in the amount of fines leads to an increase in density of the soil, which results in an increase in strength. Then, the monotonic shear strength of the mixtures was estimated using the concept of granular void ratio. It was found that the shear strength of mixtures is greatly dependent on the skeleton structure of sand particles.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.346-348
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• 2003

In this study, we attempted to estimate the discharge of the Amazon River branches from JERS-1/SAR images, which are independent of the weather. We visualized some traces of the Amazon River branches, transformed river shapes into a one-dimensional signal, and calculated the characteristics of the river shapes such as the meandering wavelength and the amplitude with Fourier and wavelet analysis. Then, we related the characteristics of the river shapes with the existing discharge data and derived some regression equations. Finally, we estimated the discharge of the Amazon River branches from the SAR images.

• Geomechanics and Engineering
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• v.19 no.3
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• pp.229-240
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• 2019

The physical models are useful to understand the soil behaviour. Hence, these tools allow validating analytical theories and numerical data. This paper addresses the design, construction and implementation of a physical model able to simulate the soil liquefaction under different cyclic actions. The model was instrumented with a piezoelectric actuator and a set of transducers to measure the porewater pressures, displacements and accelerations of the system. The soil liquefaction was assessed in three different grain size particles of a natural sand by applying a sinusoidal signal, which incorporated three amplitudes and the fundamental frequencies of three different earthquakes occurred in Colombia. In addition, such frequencies were scaled in a micro shaking table device for 1, 50 and 80 g. Tests allowed identifying the liquefaction susceptibility at various frequency and displacement amplitude combinations. Experimental evidence validated that the liquefaction susceptibility is higher in the fine-grained sands than coarse-grained sands, and showed that the acceleration of the actuator controls the phenomena trigging in the model instead of the displacement amplitude.

• Journal of The Geomorphological Association of Korea
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• v.26 no.3
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• pp.43-52
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• 2019

Place names or toponyms including Gosan, Busan and Buraesan can be very important and interesting storytelling subjects in terms of geomorphology and folklore studies also. Several studies done by folklorists, those sixty five mountain-moving stories with similar names can be grouped into several categories through formation processes and origin, transport media and imposition of tax. Geomorphological studies can focus on transport media. They can be classified into six different categories; 1) flood from upstream through river, 2) voluntary walk of mountains, 3) by wind, 4) upwelling from underground, 5) involvement of mythical beings such as Mago Granny or Dokkaebi (kind of goblin), or 6) migration by ocean current.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.2
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• pp.195-204
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• 2016

In this paper, the applicability and usefulness of windprofiler input data were investigated to generate three dimensional wind field. A logical diagnostic model CALMET with windprofiler data at ten sites and with weather forecasting model WRF output was evaluated by statistically comparing with the radiosonde data at eight sites. The horizontal wind speed from CALMET simulated with hourly windprofiler data is in good agreement with radiosonde observations within 1.5 m/s of the root mean square error, especially local circulation of wind such as sea breeze over the coastal region. The root mean square error of wind direction ranged $50^{\circ}{\sim}70^{\circ}$ is due to the wind direction error from the windprofiler polluted by ground clutters. Since the exact wind can be produced quickly and accurately in most of the altitude with windprofiler data on CALMET, we expect the method presented in this study to be useful for the monitoring of safe environment as well as weather in the coastal zone.

• Economic and Environmental Geology
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• v.48 no.5
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• pp.421-429
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• 2015

Base researches in geoscience and mineral resources, such as geological and geo-thematic mapping, geological survey and observation, have long-term, continuity and time-leasing characteristics and they are difficult to present the particular research stages or progressions in the research span. The Technology Readiness Levels (TRLs), developed by the U.S. National Aeronautics and Space Administration (NASA), is effective for presenting research maturity levels and progression in the development of new technologies. This study suggests adjusted definitions for the Technology Readiness Levels to fit Geo-technology (Technology in Geoscience and Mineral Resources). Base geological researches, including mapping, surveys and observation, can be also presented in research levels from TRL 1 (R&D planning, literature survey) to TRL 9 (geological information construction and service in all target areas) in terms of the final product's coverage. Moreover, not only development and construction of commercial products, geological disasters and environmental researches can also be presented in field demonstrations through public pilot applications. The modified commercialization or cemonstration TRLs in Geo-technology are TRL 5 (starting pilot field application), TRL 6 (pilot field operation) and TRL 7 (pilot field operation for a larger scale, greater than ten percent of the actual environment).

• Journal of the Korean GEO-environmental Society
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• v.13 no.11
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• pp.5-10
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• 2012

Many electric poles in the softground have been collapsed due to external load. In this study, several tests were performed with variation of numbers and depths of anchor blocks to find effects of anchor blocks on stability of concrete electric poles through earth pressure and displacement analysis. 1.50m depth of anchor block seems appropriate among three kinds of depths. The 2.25m depth of anchor block makes larger displacement due to disturbance caused by excessive excavation. The deeper anchor block, the less earth pressure of passive zone, an active earth pressure gets larger. When two anchor blocks were installed, displacement at top pole decreased 43.8% and 55.6% at ground when 1 anchor block was installed.

• Journal of the Korean GEO-environmental Society
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• v.7 no.4
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• pp.63-71
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• 2006

This study was conducted to evaluate air injection mode on stabilization of landfill gas and to predict the time for landfill mining. It took 8 times longer for pulse aeration to get to aerobic condition, compared to continuous aeration. It was evaluated that continuous aeration mode is more preferable than pulse mode for rapid air exchange in landfill mining. High correlation ($r^2$ = 0.95) was found between continuous aeration time and time to maintain aerobic condition when $0.2m^3/min$ of air was continuously injected and stopped. The aerobic condition ($CH_4$ < 5%) was maintained for 1.5 times longer than aeration time.

• Journal of Astronomy and Space Sciences
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• v.18 no.2
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• pp.101-108
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• 2001

Low resolution spectroscopic observations of leo-stationary satellites over the Korean peninsula have been carried out at the KyungHee Optical Satellite Observing Facility (KOSOF) with a 40cm telescope. We have observed 9 telecommunication satellites and 1 weather satellite of 6 countries. The obtained spectral data showed that satellites could be classified and grouped with similar basic spectral feature. We divided the 10 satellites into 4 groups based on spectral slop and reflectance. It is suggested that the material types of the satellites can be determined through spectral comparisons with the ground laboratory data. We will continuously observe additional geo-stationary satellites for the accurate classification of spectral features.