• Economic and Environmental Geology
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• v.24 no.4
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• pp.435-446
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• 1991

Ductile shear zones developed in Jurassic granites in the Yonggwang area show NE trend at the eastern part and nearly EW trend at the western part, respectively. Judged from shear sense indicators, they have resulted from dextral strike-slip movement. The intersection of both trends is thought to be due to the truncation and offset of NE shear zone Chonju Shear zone by the brittle Yonggwang fault which runs in near EW direction with sinistral movement sense. The simple shear deformation was predominate through the deformation in this ductile shear zone. Based on this deformation mechanism, the shear strain (${\gamma}$) estimated in domain 1 increases from 0.14 at the shear zone margin to 9.41 toward the center of shear zone. Total displacement obtained only from this measured section(JK 59 to JK14) appecars to be 1434.5 meters. The sequential development of microstructures can be divided into three stages; weakly-foliated, well-foliated and banded-foliated stages. In the weakly-foliated stage dislocation glide mechanism might be predominant. In the well-foliated stage grain boundary migration and progressive misorientation of subgrains was remarkable during dynamic recovery and recrystallization. In the banded-foliated stage grain boundary sliding and microfracturing mechanisms accompanied with crushing and cracking were marked. According to strain analysis from quartzites of the metasedimentary rocks, strain intensity (${\gamma}$) of the samples within the ductile shear zone ranges from 2.7 to 5.7, while that of the samples out of the ductile shear zone appears to be about 1.7.

• The Korean Journal of Petroleum Geology
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• v.13 no.1
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• pp.1-16
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• 2007

The southeastern Korean Peninsula has experienced crustal multi-deformations according to changes of global tectonic setting during the Cenozoic. Characteristic features of the crustal deformations in relation to major Cenozoic tectonic events are summarized as follows. (1) Collision of Indian and Eurasian continents and abrupt change of movement direction of the Pacific plate (50${\sim}$43 Ma): The collision of Indian and Eurasian continents caused the eastward extrusion of East Asia block as a trench-rollback, and then the movement direction of the Pacific plate was abruptly changed from NNW to WNW. As a result, the strong suction-force along the plate boundary produced a tensional stress field trending EW or WNW-ESE in southeastern Korea, which resultantly induced the passive intrusion of NS or NNE trending mafic dike swarm. (2) Opening of the East Sea (25${\sim}$16 Ma): The NS or NNW-SSE trending opening of the East Sea generated a dextral shear stress regime trending NNW-SSE along the eastern coast line of the Korean Peninsula. As a result, pull-apart basins were developed in right bending and overstepping parts along major dextral strike slip faults trending NNW-SSE in southeastern Korea. The basins can be divided into two types on the basis of geometry and kinematics: Parallelogram-shaped basin (rhombochasm) and wedged-shaped basin (sphenochasm), respectively. In those times, the basins and adjacent basement blocks experienced clockwise rotation and northwestward tilting contemporaneously, and the basins often experienced a kind of propagating rifting from NE toward SE. At about 17Ma, the Yonil Tectonic Line, which is the westernmost border fault of the Miocene crustal deformation in southeastern Korea, began to move as a major dextral strike slip fault. (3) Clockwise rotation of southeastern Japan Island (about 15 Ma): The collision of the Izu-Bonin Arc and southeastern Japan Island, as a result of northward movement of the Philippine sea-plate, induced the clockwise rotation of southeastern Japan Island. The event caused the NW-SE compression in the Korea Strait as a tectonic inversion, which resultantly tenninated the basin extension and caused local counterclockwise rotation of blocks in southeastern Korea. (4) E-W compression in the East Asia (after about 5 Ma): Decreasing subduction angle of the Pacific plate and eastward movement of the Amurian plate have constructed the-top-to-west thrusts and become a major cause for earthquakes in southeastern Korea until the present time.

• The Korean Journal of Petroleum Geology
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• v.1 no.1 s.1
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• pp.15-27
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• 1993

Seismic reflection profiles from the eastern continental margin of Korea delineate three major Neogene sedimentary basins perched on the shelf and slope regions: Pohang-Youngduk, Mukho and Hupo basins. The stratigraphic and structural analyses demonstrate that the formation and filling of these basins were intimately controlled by two phases of regional tectonism: transtensional and subsequent contractional deformations. In the Oligocene to Early Miocene, back-arc opening of the East Sea induced extensional shear deformation with dextral strike-slip movement along right-stepping Hupo and Yangsan faults. During the transtensional deformation, the Pohang-Youngduk Basin was formed by pull-apart opening between two strike-slip faults; in the northern part, block faulting caused to form the Mukho Basin between basement highs. As a result of the back-arc closure, the stress field was inverted into compression at the end of the Middle Miocene. Under the compressive regime, two episodes (Late Miocene and Early Pliocene) of regional deformation led to the destruction and partial uplift of the basin-filling sequences. In particular, during the second episode of compressive deformation, the Hupo fault was reactivated with an oblique-slip sense, which resulted in an opening of the Hupo Basin as a half-graben on the downthrown fault block.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.775-784
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• 2009

Weathered foliation could act as a critical failure plane because this type of plane tend to have low roughness and long extensions. A big constructed slope at $\bigcirc\bigcirc$ road construction site was failed due to the block movement along a fault zone which is parallel to foliation. Tectonic activity reactivated a fault zone parallel to foliation, and the fault clay within the shear zone metamorphosed retrogressively to chrolite. The failed block moved when the block weigh lost the balancing with the resisting force of the retrogressively metamorphosed chrolite. Evaluating the three dimensional distribution of the foliation was critical for establishing a plan for the stabilization of the slope. For this purpose, 10 boreholes were drilled as a lattice distribution, and the BIPS analyses are performed at each boreholes. The fractures measured in the boreholes are projected into 15 cross sections and their distributions are analysed, using Fracjection software. The projection analyse show that the strike of the foliation gets dipper towards left side of the slope. This geometry indicates that there are more failure block geometry at left side of the slope. Potential failure planes are searched using the projection method, and these information are provided for further support design.

• Economic and Environmental Geology
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• v.23 no.1
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• pp.59-71
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• 1990

Magnetic anisotropy of a total of 213 independently oriented Tertiary rock samples from Pohang-Ulsan area has been studied. The sampled strata comprise basalts, tuffs and black shale, and range in age from Eocene to Miocene. The previous palaeomagnetic studies indicate that their magnetic carrier minerals are titanomagnetites. Among 23 sampled sites, 11 sites were found to preserve magnetic load foliation parallel to the bedding plane caused by the Iithostatic load of the overlying strata. Other 4 sites showed magnetic lineation indicating the flow direction of lava and tuffs. The remaining 8 sites revealed the magnetic tectonic foliation nearly vertical to the bedding plane. This magnetic foliation is interpreted to be generated by tectonic compression which acted nearly horizontally during the solidification stage of the strata. The compression directions deduced from the tectonic foliation of the 8 sites can be grouped into internally very consistent two group: a N-S trending one and the other WNW-ESE trending one. It is interpreted that the former N-S compression was associated with the N-S spreading of the East Sea(Sea of Japan) and the dextral strike-slip movement of the Yangsan-Ulsan fault system. The latter WNW-ESE compression is interpreted to represent the folding and reverse faulting activity in the Korean and Tsushima straits during middle/late Miocene times.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.139-144
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• 2005

Multichannel seismic survey has conducied along the South Scotia Ridge which is located in the northern part of Weddell sea, Antarctic sea, The South Scotia Ridge is part of continental crust extended from Antarctic Peninsula. It borders on Oceanic plates, the Scotia sea plate and Powell basin. Transtensional tectonics along the sinistral transform fault plate boundary led to the creation of the present tectonic geomorphology of the South Scotia Ridge. The fan-shaped deposits with angular unconformities in the central depression is interpreted as a divergent tectonic movement along the ridge.

• The KIPS Transactions:PartB
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• v.8B no.5
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• pp.493-500
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• 2001

Video scene segmentation is fundamental role for content based video analysis. In this paper, we propose a new region based video scene segmentation method using continuity test for each object region which is segmented by the watershed algorithm for all frames in video data. For this purpose, we first classify video data segments into classes that are the dynamic and static sections according to the object movement rate by comparing the spatial and shape similarity of each region. And then, try to segment each sections by grouping each sections by comparing the neighbor section sections by comparing the neighbor section similarity. Because, this method uses the region which represented on object as a similarity measure, it can segment video scenes efficiently without undesirable fault alarms by illumination and partial changes.

• Journal of the Korean Society for Heat Treatment
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• v.15 no.6
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• pp.272-278
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• 2002

The changes in damping capacity with volume fractions of thermal and deformation-induced ${\varepsilon}$ martensites were compared and analyzed in an Fe-23%-Mn alloy. The volume fraction of thermal ${\varepsilon}$ martensite increased with decreasing cooling temperature, whereas that of deformation-induced ${\varepsilon}$ martensite increased steeply up to 10%- of cold rolling and nearly saturated in further cold rolling. In the case of thermal ${\varepsilon}$ martensite, the damping capacity increased linearly with the increase in ${\varepsilon}$ martensite content. For the deformation-induced ${\varepsilon}$ martensite, however, the damping capacity increased continuously up to 70%- of ${\varepsilon}$ martensite, over which it decreased suddenly. TEM microstructures showed that the deterioration of damping capacity above 70%- of deformation-induced ${\varepsilon}$ martensite is ascribed to the introduction of perfect dislocations, which play a important role in inhibiting the movement of damping sources such as stacking fault boundaries inside ${\varepsilon}$ martensite, ${\varepsilon}$ martensite variant boundaries and ${\gamma}/{\varepsilon}$ interfaces.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.983-989
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• 2015

Power transformer is one of the major and key apparatus in electric power system. Monitoring and diagnosis of transformer fault is necessary for improving the life period of transformer. The failures caused by short circuits are one of the causes of transformer outages. The short circuit currents induce excessive forces in the transformer windings which result in winding deformation affecting the mechanical and electrical characteristics of the winding. In the present work, a transformer producing only the radial flux under short circuit is considered. The corresponding axial displacement profile of the windings is computed using Finite Element Method based transient structural analysis and thus obtained displacements are compared with the experimental result. The change in inter disc capacitance and mutual inductance of the deformed windings due to different short circuit currents are computed using Finite Element Method based field analyses and the corresponding Sweep Frequency Responses are computed using the modified electrical equivalent circuit. From the change in the first resonant frequency, the winding movement can be quantified which will be useful for estimating the mechanical withstand capability of the winding for different short circuit currents in the design stage itself.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.411-414
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• 2014

Numerical modeling was conducted to estimate the amount of dislocation that may occur across a frictionless fracture during an earthquake using commercial code FLAC3D (Fast Lagrangian Analysis of Continua in 3 Dimensions). The applied motion was calculated to represent a Richter 6.0 magnitude earthquake at distances of 2 km from the fracture. The velocity-time history was generated from Svensk $K{\ddot{a}}arnbr{\ddot{a}}anslehantering$ AB report. In the report, The velocity field resulting from an earthquake on a fault located in the near-field (2 km distance) was modelled using a finite difference program, WAVE. The stress-time history was substituted for velocity-time history to perform dynamic analysis using FLAC3D. During the earthquake, the maximum dislocation and change of shear stress were about 1 cm and 2MPa, respectively. Because the fracture is frictionless in this study, all dislocations relax to zero after the earthquake motions have ceased.