• Journal of the Korean Geophysical Society
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• v.6 no.2
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• pp.89-97
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• 2003

For safety evaluation of a rockfill dam, it is often necessary to investigate spatial distribution and dynamic characterization of weak zones such as fractures. For this purpose, both seismic and electric methods are adopted together in this research. The former employs the multichannel analysis of surface waves (MASW) method, and aims at the mapping of 2-D shear-wave velocity (Vs) profile along the dam axis that can be associated with dynamic properties of filled materials. The latter is carried out by DC- resistivity survey with a main purpose of mapping of spatial variations of physical properties of dam materials. Results from both methods are compared in their signature of anomalous zones. In addition, downhole seismic survey was carried out at three points within the seismic survey lines and results by downhole seismic survey are compared with the MASW results. We conclude that the MASW is an efficient method for dynamic characterization of dam-filling materials, and also that joint analyses of these two seemingly unrelated methods can lead to an effective safety evaluation of rock-fill dam.

• Journal of the Korean Geophysical Society
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• v.6 no.2
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• pp.99-105
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• 2003

Rayleigh waves which has more than 70% of the total seismic energy is the principal component of ground roll. Frequency component of a surface wave has a different propagation velocity, that is, phase velocity, which results in a different wavelength called dispersion. Rayleigh wave is one of the most common ways to use the dispersive properties of surface waves. MASW is a seismic method to evaluate shear-wave velocity information of the ground.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.860-868
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• 2008

Seismic safety analysis of rockfill dams are consist of the stability analysis as an simplifed method and the dynamic analysis as an detailed method. When high risk dams such as Multi-purpose dams were often applied detailed method by dynamic analysis, dynamic properties of dam materials such as shear modulus are considered as most important factor. Dynamic material properties such as shear modulus had to be investigated by cyclic triaxial test et al. during design and construction stage but these were not conducted because of the condition of domestic seismic design technique. MASW and SASW methods had been applied as a non destructive method to investigate dynamic material properties of existing rockfill dam, has no problems in dam safety at present. These methods were usually performed under the assumptions that the subsurface can be described horizontally homogeneous and isotropic layers. Recent studies(Marwin, 1993, Kim, 2001) showed that surface waves generated through inclined structures have different characteristics from those through a horizontally homogeneous layered model. further Kim et al(2005) and Min and Kim(2006) showed that central core type rockfill dam overestimated the shear wave velocities as increasing the depth through the 3D numerical modelling dut to the effect of outer rockfill and geometrical reasons In this study the results of shear wave velocities of seven rockfill dams form comprehensive facility review, was carried out from 2003 to 2007, were collected and analysed to establish the shear wave velocity distribution characteristics in increasing confining stress in rockfill dams and surface wave velocity ranges in rockfill dam through MASW and the limitation in application are discussed to be utilized as an reference value for dynamic analysis.

• Fisheries and Aquatic Sciences
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• v.27 no.2
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• pp.122-135
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• 2024

Obesity is a disease involving mechanisms of fat accumulation, low-grade inflammatory cytokine release, and mitochondrial dysfunction. The aim of the current study was to investigate the effects of abalone intestine extract on fat metabolism in 3T3-L1 adipocytes and high fat diet-induced zebrafish larvae. The total phenol content was highest in subcritical water extract at 210℃ (SW210) among hot water, ethanol, and subcritical water extracts of abalone intestine. In addition, SW210 of male abalone intestine (MASW210) most effectively controlled the lipid accumulation and expression of adipogenic or lipogenic regulators (PPAR-γ, C/EBPα, SREBP-1c, and FAS) in 3T3-L1 adipocytes. Likewise, in zebrafish larvae fed high fat, MASW210 significantly suppressed body weight, glucose levels, and lipid accumulation. The mRNA expression related to adipogenesis (PPAR-γ and C/EBPα), lipogenesis (SREBP-1c and FAS), inflammatory cytokines (TNF-α and IL-6), energy m/;.etabolism (AMPK, lepr, SIRT1, and adiponectin), and mitochondrial biogenesis (PGC-1α and CPT-1) were significantly regulated by treatment with MASW210. These results suggest that abalone intestine extract such as MASW210, are useful biomaterials for improving obesity and metabolic diseases.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.17-22
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• 2006

Shear modulus is directly linked to material's stiffness and is one of the most critical engineering parameters. Seismically, shear-wave velocity (Vs) is its best indicator. Although methods like refraction, down-hole, and cross-hole shear-wave surveys can be used, they are generally known to be tougher than any other seismic methods in field operation, data analysis, and overall cost. On the other hand, surface waves, commonly known as ground roll, are always generated in all seismic surveys with the strongest energy, and their propagation velocities are mainly determined by Vs of the medium. Furthermore, sampling depth of a particular frequency component of surface waves is in direct proportion to its wavelength and this property makes the surface wave velocity frequency dependent, i.e., dispersive. The multichannel analysis of surface waves (MASW) method tries to utilize this dispersion property of surface waves for the purpose of Vs profiling in 1-D (depth) or 2-D (depth and surface location) format. The active MASW method generates surface waves actively by using an impact source like sledgehammer, whereas the passive method utilizes those generated passively by cultural (e.g., traffic) or natural (e.g., thunder and tidal motion) activities. Investigation depth is usually shallower than 30 m with the active method, whereas it can reach a few hundred meters with the passive method. Overall procedures with both methods are briefly described.

• Geotechnical Engineering
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• v.17 no.11
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• pp.10-19
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• 2001

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.352-359
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• 2005

In this study, seismic refraction survey and MASW at dam crest and down-hole test and cross hole test in the boring holes located in dam crest through the core are performed to fin out dynamic material properties, are needed to evaluate dynamic safety of rockfill dam using dynamic analysis method. From the field test and geophysical exploration, applied such as above, p-wave and s-wave velocity profile of each layer of dam body. Dynamic material properties, such as elastic modulus, shear modulus, poissong's ration, are obtained from p-wave and s-wave velocity profile and density profile from formation density logging test.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.467-474
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• 2002

Colluvial sell has a very unique deformation property, particularly when it is subject to the cutting work entailed in a variety of construction. In this study, the cut slope tying on a colluvial layer in which the transmission tower had been installed were investigated to find out the cause of deformation. In-situ tests such as boring, surface-wave analysis (MASW) were employed to look into the physical composition of underground layers and FEM including LEM were carried out to simulate the construction steps. The result shows that the stress relaxation followed by road construction induced the deformation of the slope and damage in the foundation of the transmission tower.

• Journal of the Korean Geophysical Society
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• v.6 no.4
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• pp.245-259
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• 2003

Two multichannel analysis of surface wave (MASW) surveys were conducted over a soil site in Tacoma Water's Green River Facility, Washington, where construction of a chemical treatment facility had been planned. The purpose of the surveys was to compare soil stiffness characterized by shear-velocity (Vs) distribution before and after Deep Dynamic Compaction (DDC) operation that was designed to improve the soil stiffness. Site soil consisted of very heterogeneous gravel and cobbles in a sand-and-silt matrix. Results from each survey are represented by two 2-D Vs maps delineating Vs variation of soil below the surveyed lines. One map was constructed from those dispersion curves that were analyzed with a significant amount of subjective judgment involved, whereas the other map was constructed from those dispersion curves analyzed with as much objective information as possible. Comparison of 2-D Vs maps indicates that Vs actually decreased after the DDC operations, possibly due to the loss (or reduction) of cohesive bonding between soil particles caused by the compaction operations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.393-405
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• 2020

Various geotechnical information is required to evaluate the stability of the ground and a foundation once liquefaction occurs due to earthquakes, such as the soil strength and groundwater level. The results of the Standard Penetration Test (SPT) conducted in Korea are registered in the National Geotechnical Information Portal System. If geotechnical information for a non-drilled area is needed, geostatistics can be applied. This paper is about the feasibility of obtaining ground information by the Empirical Bayesian Kriging (EBK) method and the Inverse Distance Weighting Method (IDWM). Esri's ArcGIS Pro program was used to estimate these techniques. The soil strength parameter of the drilling area and the level of groundwater obtained from the standard penetration test were cross-validated with the results of the analysis technique. In addition, Multichannel Analysis of Surface Waves (MASW) was conducted to verify the techniques used in the analysis. The Buk-gu area of Pohang was divided into 1.0 km×1.0 km and 110 zones. The cross-validation for the SPT N value and groundwater level through EBK and IDWM showed that both techniques were suitable. MASW presented an approximate section area, making it difficult to clearly grasp the distribution pattern and groundwater level of the SPT N value.