• Economic and Environmental Geology
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• v.38 no.2 s.171
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• pp.143-153
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• 2005

Euiseong subbasin, included in the Kyungsang Basin, was created by the result of volcanic activity in the late Cretaceous, and contacts with Milyang and Youngyang subbasins by Palgongsan and Andong faults, respectively. In this study, geophysical survey is implemented fur investigating surface and subsurface geologic structure in Euiseong subbasin which composed with the complex of volcanic and plutonic rocks. To understand surface geologic feature, IRS satellite image and DEM(Digital Terrain Map) are used for analyzing lineament and its density. The numbers of lineaments show major trend in $N55^{\circ}\~65^{\circ}W$, and aspects of lineament lengths show major trend in $N55^{\circ}\~65^{\circ}W$ and N-S directions. 13 delineate subsurface density discontinuity; Power spectrum analysis was implemented for gravity anomaly data, resulting $4-5{\cal}km$ depth of basin basement and $0.5-0.6{\cal}km$ depth of shallow discontinuity. From the result of power spectrum analysis, 2.5-D modelings were implemented along two profiles of A-A' and B-B', and they show subsurface geology in detail. Analytic signal method for detecting boundaries of magnetic basements show 0.001-130 nT/m values, and high energy area show good correspondency with the boundaries of Palgongsan granite and caldera areas in Euiseong subbasin.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.268-275
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• 2018

The purpose of this study is to investigate what items are needed for reemployment according to the life cycle of women and to provide basic data to address the career discontinuity of women. The study selected five women currently unemployed living in Daejeon who were taking classes related to entrepreneurship at the Cultural Center and the Women Resource Development Center. The data collection period was from October to December, 2017, and collected from in depth interviews. An open-ended interview was used to explore the content of the interview process. The results of the study are as follows: Support policies for women with career disruptions should, above all, be given priority over career support to ensure that currently employed women do not quit their jobs due to marriage, childbirth or childcare. In addition, there is a need to improve the relevant systems and to implement vocational education and training programs so that women with career discontinuity can reenter the labor market. To do this, it is necessary to establish and support career planning in order to understand the effects of women's lifecycles and to support women's economic activity.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.103-107
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• 2005

In order to investigate the velocity structure of the southern part of the Korean peninsula, exploded seismic signals were recorded for 120 s along a 294-km WNW-ESE line and 150 s along a 335-km NNW-SSE line in 2002 and 2004, respectively. Velocity tomograms were derived from inverting first arrival times. One-dimensional velocity models derived by joint analyses of teleseismic receiver functions and surface wave dispersion at several stations near the profiles were uesd to build initial models. The raypaths indicate several midcrust interfaces including ones at approximate depths of 2.0 and 14.9 km with refraction velocities of approximately 6.0 and 7.1 km/s, respectively. The deepest significant interface varies in depth from 30.8 km to 36.1 km. The critically refracting velocity varies from 7.8 to 8.1 km/s along this interface which may correspond to the Moho discontinuity. The velocity tomograms show (1) existence of a low-velocity zone centered at 6-7 km depth under the Okchon fold belt, (2) extension of the Yeongdon fault down to greater than 10 km, and (3) existence of high-velocity materials under the Gyeongsan basin whose thickness is less than 4.2 km.

• Journal of the Korean Geophysical Society
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• v.8 no.1
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• pp.45-48
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• 2005

In order to investigate the velocity structure of the southern part of the Korean peninsula, exploded seismic signals were recorded for 120 s along a 294-km WNW-ESE line and 150 s along a 335-km NNW-SSE line in 2002 and 2004, respectively. Velocity tomograms were derived from inverting first arrival times. One-dimensional velocity models derived by joint analyses of teleseismic receiver functions and surface wave dispersion at several stations near the profiles were uesd to build initial models. The raypaths indicate several midcrust interfaces including ones at approximate depths of 2.0 and 14.9 km with refraction velocities of approximately 6.0 and 7.1 km/s, respectively. The deepest significant interface varies in depth from 30.8 km to 36.1 km. The critically refracting velocity varies from 7.8 to 8.1 km/s along this interface which may correspond to the Moho discontinuity. The velocity tomograms show (1) existence of a low-velocity zone centered at 6-7 km depth under the Okchon fold belt, (2) extension of the Yeongdon fault down to greater than 10 km, and (3) existence of high-velocity materials under the Gyeongsan basin whose thickness is less than 4.2 km.

• Economic and Environmental Geology
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• v.40 no.6
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• pp.751-759
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• 2007

To better understand the subsurface geological structure of the Kunsan Basin in the Yellow Sea, the mean depths of the density discontinuous layers (DDLs) of the Kunsan Basin were calculated by power spectrum analysis using satellite altimetry gravity data. The calculated mean depths of DDLs were -1.1km, -3.4km, -9.1km and -31.0km. The mean depth of -1.1km DDL was interpreted as regional unconformity shown in about 1 second in two way travel time (TWTT) in the seismic reflection profiles, and the mean depth of -3.4km DDL was also interpreted as top of the acoustic basement in the seismic reflection profiles. Comparing with well data, seismic reflection profiles and regional geology in the study area, the mean depth of -9.1km DDL was interpreted as top of the igneous origin basement. This means that the acoustic basement of the study area is composed mainly of sediments which are disregarded in previous study. The mean depth of -31.0km DDL was interpreted as the Moho discontinuity because this mean depth is similar to one of the normal continental crust thickness. The detection of top of the igneous origin basement suggests that oil gas potential analysis in Kunsan Basin needs to be extended to the deeper part of sediments (acoustic basement).

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.13 no.2
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• pp.122-138
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• 2001

It is well known that whcn waves propagating on a shallow water suddenly encounter a much deeper water they do not propagate further but are reflected. If we apply this phenomenon to a harbor by making the harbor depth much greater than outside, we could improve the harbor tranquillity by making the waves impinging into the harbor be reflected at the harbor entrance. In the present paper, first we apply the numerical models based' on the mild-slope equation and extended mild-slope equation to calculate the long wave resonances in a rectangular harbor with a very large depth discontinuity at its entrance to find that the difference between the models is almost negligible. By applying the numerical model to a realistic model harbor whose inside is entirely dredged, it is found that the effect of dredging is insignificant when the inside depth is twice the outside one but tripled inside depth significantly reduces the long waves of period of one to five minutes whieh may exert a bad influence on ship motion. Moreover, even when only a portion of the harbor basin is dredged, the cffect of dredging in the dredged area is found to be comparable to that of entire dredging, showing that the dredging of harbor basin can be a countenncasure for harbor resonance.

• Journal of Korean Society of Steel Construction
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• v.25 no.1
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• pp.47-59
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• 2013

This study that is a successive secondary study right after the primary bending strength test of a new form of U-shape hybrid composite beam is a cyclic seismic test of U-shape hybrid composite beam and column conncetion. Three specimens are built for the variables which are kinds of columns, depth of beam, continuity or discontinuity of upper plate of beam, and a number of steel bars of end-beam. Kinds of columns are a reinforcement concrete column and a ACT column of CFT shape, and beam depth are 300, and 500 mm. Detail of connection is bolt connection with using a short bracket that is commonly use. As the result, deformability of 2~4% is ensured the floor displacement angle. If it is the negative moment, the maximum moment shows that its capacity is above the nominal moment.

• Composites Research
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• v.25 no.2
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• pp.40-45
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• 2012

The comparison of the numerical results with those measured by the experiment showed good agreement. The design of composite joint which is the weakest part in the composite structures has become a very important research area since the composite materials are widely used in the aircraft and machine structure. In this paper, the new composite key joints that minimize the fiber discontinuity and strength degradation of adherend were proposed and their failure loads were evaluated. The failure index and damage area method were used for the failure prediction of the composite key joint. From the tests, the failure load of the composite key joint was 93% larger than that of a mechanical joint and the key joint whose slot depth and edge length were 0.88mm and 20mm had the largest failure load. Also, the analytic failure modes by the failure index and damage area were compared with experimental failure modes.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.10
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• pp.1069-1077
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• 2015

In tunnel excavation using blast, the wire saw rock cutting method generates a discontinuity perimeter around the center cut, and thus prevents blast vibration propagation to reduce vibration and noise. Therefore, the method is expected to be easy to use and economical compared with other methods. In this paper, the cutting mechanism of wire saw in tunnel excavation is investigated. A model describing the changes in cutting depth and wire saw shape inside a rock during cutting is established and validated for this purpose. Through a simulation using the model, the important characteristics of wire saw cut are investigated, and the influences of cutting conditions, such as wire saw tension, wire saw speed, feed speed, depth, and diameter of boring, on cutting performance are also examined. A method to improve the cutting performance is proposed based on the results.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.213-219
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• 1992

Geomorphological properties for the phylite-derived soil were examined to relate processes to four landscape positions, shoulder, backslope, footslope, and toeslope in Chungbuk. The distribution of Ogcheon-geology system was 216 thousand ha in South Korea. 2 orders, 3 suborders, 4 great groups, 5 subgroups, and 9 series were mapped. Soil color was interlocked by landscape. Soil color index values and $Fe_2O_3$ contents increased with soil-drainge class. Silt/clay and Ca/Mg ratios tended to narrow wish elevation and decreased with depth. Therefore, profile development or age on the landscape position was shoulder>backslope>footslope>toeslope. Color index(C2m) has a sighificant correlation with $Fe_2O_3$, in soil profile($r=0.777^{**}$). Pedologic type was continuity/discontinuity and soil property changes of depth<12cm would have a continous function.