• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.676-683
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• 2003

A laboratory experiment using artificial fracture rocks was used to understand the 3-dimensional dispersion of a tracer and the mixing process in a fractured network. In this experiment, 12cm polystyrene foam cubes with two electrodes for monitoring electric conductivity (EC) were used as artificial fractured rocks. Distilled water with 0.5mS/m was used as a tracer in water with 35mS/m and the difference of EC between the tracer and the water was monitored by a multipoint simultaneous measurement system of electrical resistance. The results showed that even if the fracture arrangement pattern was not straight in the direction of the flow, the tracer did not diffuse along individual fractures and an oval tracer plume, which was the distribution of tracer concentrations, tended to be form in the direction of the flow. The vertical cross section of the tracer distribution showed small diffusivity in the vertical direction. The calculated total tracer volume passing through each measurement point in the horizontal cross section showed while that the solute passed through measurement points near the direction of hydraulic gradient and in other directions, the passed tracer volumes were small. Using Peclet number as a criterion, it was found that the mass distribution at the fracture intersection was controlled in the stage of transition between the complete mixing model and the streamline routing model.

• Geophysics and Geophysical Exploration
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• v.7 no.2
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• pp.105-108
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• 2004

Immersive virtual reality has been used in areas of oil and gas exploration for visualization and analysis of various spatial data, such as wireline logs, 3-dimensional seismic data volume, formational boundaries, fault, and some other reservoir characteristics. Although virtual reality is a valuable tool in this area, in most cases, it requires a large budget. This paper describes the construction of a single screen, passive stereo, virtual reality, display system based on commodity, or otherwise, low-cost components. The core elements of the system are a PC with a two-channel 3-D graphics, two projects, and a polarized stereo. There are many options available for the major elements of such a system, and the basic system can be modified or adapted to many different styles of use.

• The Journal of the Petrological Society of Korea
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• v.20 no.4
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• pp.243-250
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• 2011

This study considers the historical eruption record in 1702 from the volcanological point of view, which is presumed to have occurred from Mt. Baegdusan volcano. The minium volume of erupted materials is estimated to be $1.2km^3$ when calculated with an empirical formula using an isopach line obtained from two points 140 km away from the vent. The 1702 eruption was a paroxysmal one with VEI of 5. The historical record described a deposition of wind-modified fallout ash by movement of hot ash cloud. To prepare for the future eruption, we have to analyze historical literatures and understand characteristics of volcano.

• Ecology and Resilient Infrastructure
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• v.3 no.2
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• pp.126-129
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• 2016

The risk of flooding and groundwater depletion is increasing due to the increase of impervious area in an urban area that reduces the volume of infiltration and increases the outflow of rainwater. The objective of this study is to examine the impact of installation of roadside tree protectors with infiltration pipes in terms of the change of the infiltration rate. Through this study, it has been attested that roadside tree protectors with infiltration pipes increased the infiltration rate and decreased water level on the ground, and could be applied in an urban area as the low impact development (LID) facilities.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.13 no.1
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• pp.41-47
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• 1995

In this study, we try to develope the radio control photographing system with 35 mm camera to obtain 3-dimension large scale geographic information more effectively, to automatize and computerize the basic design and practical design of road. By applying this system on getting data which is needed to design road, this study has an object to promote efficiency in possesion and management of geographic information. As result of this study, this system could obtain geographic information effectively on the object region, could get large scale geographic information which was suitable for expected accuracy by photographing in 400 m height and could ac-quire profile, crossection and earth-work volume quickly and exactly.

• Advances in materials Research
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• v.8 no.3
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• pp.155-177
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• 2019

In this paper, a new displacement based high-order shear deformation theory is introduced for the static response of functionally graded sandwich plate with new definition of porosity distribution taking into account composition and the scheme of the sandwich plate. Unlike any other theory, the number of unknown functions involved is only four, as against five in case of other shear deformation theories. The theory presented is variationally consistent, has strong similarity with classical plate theory in many aspects, does not require shear correction factor, and gives rise to transverse shear stress variation such that the transverse shear stresses vary parabolically across the thickness satisfying shear stress free surface conditions. Material properties of FGM layers are assumed to vary continuously across the plate thickness according to either power-law or sigmoid function in terms of the volume fractions of the constituents. The face layers are considered to be FG across each face thickness while the core is made of a ceramic homogeneous layer. Governing equations are derived from the principle of virtual displacements. The closed-form solution of a simply supported rectangular plate subjected to sinusoidal loading has been obtained by using the Navier method. Numerical results are presented to show the effect of the material distribution, the sandwich plate geometry and the porosity on the deflections and stresses of FG sandwich plates. The validity of the present theory is investigated by comparing some of the present results with other published results.

• Journal of Digital Contents Society
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• v.18 no.4
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• pp.787-793
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• 2017

This paper proposes the IoT based monitoring system to reservoir and erosion control dam that measure amount of contained water and amount of sediment by real time through unit volume block object modeling and support the related image. The proposed system is more effective in establishing a more accurate dredging plan and effectively managing efficient water management plans, and effectively preventing accidents such as landslides, etc.

• Geophysics and Geophysical Exploration
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• v.3 no.1
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• pp.7-12
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• 2000

The paper discusses a data processing methodology that derives a three dimensional porosity volume information from the 3-D seismic dataset. The methodology consists of preprocessing and inversion procedures. The purpose of the preprocessing is balancing the amplitudes of seismic traces by using reflectivity series derived from sonic and density logs. There are eight sonic logs are available in the study area; therefore, we can compute only 8 balance functions. The balance function for every seismic trace was derived from these 8 balance functions by kriging. In order to derive a wide-band acoustic impedance --similar to the one can be derived from a sonic log- from a band-limited reflection seismogram, we need to recover missing low- and high-frequency information of the seismic trace. For that Purpose we use the autoregressive method.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.51-59
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• 1999

Chemical composition of atmospheric aerosols was measured at 4 sites in Pusan. All the samples were collected with a high volume air sampler from January to October 1996, to analyze major ions and heavy metals. Dominant ions of aerosols were S $O_4$$^{2-}$ in anion and N $a^{+}$ in cation. Sulfate, nitrate and ammonium ions in aerosols showed high enrichment factor to soil and seawater composition. The concentrations of heavy metals in aerosols was lowest at the site PI near the coast. The lowest concentrations of major ions and heavy metals mainly appeared in August, probably due to scavenging by frequent rains. Especially, the concentrations of total suspended particulate matter(TSP) and heavy metals in aerosols showed good correlations in Pusan. Based on crustal Al, enrichment factors for some metals(Zn, Cu, Pb, Cd) in aerosols were significantly greater than unity, and the order was Cd ＞ Pb ＞ Zn ＞ Cu. This evidence suggests that Cd and Pb are derived predominantly from non-crustal sources.s.

• Geomechanics and Engineering
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• v.9 no.5
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• pp.547-567
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• 2015

This study investigates the behavior of group of tapered and cylindrical piles. The bearing capacities of groups of tapered and cylindrical piles are computed and compared. Modeling of group of piles in this study is conducted in sand using three-dimensional finite element software. For this purpose, total bearing capacity of each group is firstly calculated using the load-displacement curve under specific load and common techniques. Then, the model of group of piles is reloaded under this calculated capacity to find group settlements, stress states on the lateral surfaces of group block, efficiency of group and etc. In order to calculate the efficiency of each group, single tapered and cylindrical piles are modeled separately. Comparison for both tapered and cylindrical group of piles with same volume is conducted and a relation to predict tapered pile group efficiency is developed. A parametric study is also performed by changing parameters such as tapered angle, angle of internal friction of sand, dilatancy angle of soil and coefficient of lateral earth pressure to find their influences on single pile and pile group behavior.