• Journal of the Korean earth science society
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• v.27 no.4
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• pp.464-474
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• 2006

The paleoceanography since 14 ka was reconstructed based on the planktic foraminiferal assemblages of core sediments from the outer shelf of the Korea Strait. Planktic foraminifera in the core sediments can be divided into four assemblages: A, B, C, and D. Assemblage A consists mainly of Globigerinoides ruber group and Globigerinoides conglobatus with low abundance (less than 10%), indicating the tropical-subtropical water mass. Assemblage B is composed of Pulleniatina obliquiloculata and Neogloboquadrina dutertrei, the indicator of Kuroshio Current, and shows the aspect of the inflow of the Tsushima Current into the Korea Strait. Assemblage C yields polar-subpolar species, mainly Neogloboquadrina incompta and N. pachyderma. It decreases upward of the core. Assemblage D contains coastal water species such as Globigerina bulloides and G. quinqueloba. It is abundant in the lower to middle region of the core. From the analysis of distributions of each assemblage and the result of age datings in the core, it is suggested that the Korea Strait played a role of channelling the East China Sea and the East Sea after the LGM (ca. 14 ka). During this time, the coastal water, affected by fresh waters originated from the river systems of China and/ or the Korean Peninsula, flourished around the Korea Strait and theses coastal water might entered to the East Sea. Around 8.5 ka, the effect of the Tsushima Current started to strengthen in this region, and the present current system seems to be formed at about $7{\sim}6ka$.

• Geophysics and Geophysical Exploration
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• v.14 no.1
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• pp.42-49
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• 2011

To locate anomalous features including seepage pathways through the Daeryong earth-fill dam, P and Rayleigh waves were recorded along a 250-m profile on the crest of the dam. Seismic energy was generated using a 5-kg sledgehammer and detected by 24 4.5-Hz vertical-axis geophones installed at 3-m intervals. P-wave and apparent S-wave velocities of the reservoir dam and underlying bedrock were then inverted from first-arrival traveltimes and dispersion curves of Rayleigh waves, respectively. Apparent dynamic Poisson's ratios as high as 0.46 were obtained at the base of the dam near its north-east end, where an outlet conduit occurs, and in the clay core body near the south-west end of the profile where the dam was repeatedly grouted to abate seepage before our survey. These anomalies of higher Poisson's ratios in the upper part of clay core were also associated with effusion of grout on the downstream slope of the dam during post-survey grouting to abate leakage. Combining P-wave traveltime tomography and inversion of Rayleigh wave velocities was very effective in detecting potential pathways for seepage and previous grouted zones in this earthen dam.

• Geophysics and Geophysical Exploration
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• v.20 no.4
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• pp.207-215
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• 2017

To develope shale play which is one of unconventional energy resources, horizontal drilling and hydraulic fracturing are necessary and those are applied to the place where the differential horizontal stress ratio (DHSR) is low. The differential horizontal stress ratio is generally calculated by the minimum and maximum horizontal stress, but it is also calculated from dynamic elastic constants and anisotropic parameters. In this study we analyzed anisotropic properties through the core samples from Danyang limestone and calculated DHSR. The three types of core samples shaped in three directions (vertical, parallel and 45 degree to bedding) were used for laboratory test. We measured P-, S-wave velocities, and density and then calculated dynamic elastic constants, compliance and DHSR. According to the results of the core sample analysis the calculated DHSR is 0.185. Thomsen parameters of the Danyang limestone used in this study are characterized by the P- and S-wave velocities varying along the bedding symmetry axis. It is observed that the DHSR value is more affected by the change in compliance value than the Poisson's ratio. It is necessary to measure SH-wave velocity for more correct petrophysical properties.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.123-127
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• 2005

Surface refraction and crosswell seismic survey conducted as a part of geoscientific studies applied in an area of ground water reservoir shows that, 1) the average velocity with respect to depth is about 250 m/s for the surface layer (<4m), 2,500 m/s for the weathered formation, and greater than 3,500 m/s for the bed rocks, 2) the depth to the bedrock derived from the seismic studies and the sonic log (17m) is somewhat different from the depth obtained from the core study (25m).

• Geophysics and Geophysical Exploration
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• v.6 no.4
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• pp.195-198
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• 2003

In this study, we have developed a 3-D visualization program that is helpful in the interpretation or comparisons of geologic and geophysical data, which have been acquired to understand the cause of ground subsidence in the residential area and to establish reinforcement strategy. The visualization program was developed under the Windows operating system for convenient use and easy understanding. It uses Visual C++ for the Graphic User Interface and the OpenGL for graphic handling. Since this program is user-friendly, even users who do not have the basic idea about GIS or CAD can get very useful information with this program. The applicability of the program has been verified by visualizing the real core log and resistivity tomography images obtained from the ground subsidence area. These results have shown that the program is very useful for comparisons of these two data for the interpretation of subsurface structures.

• Bulletin of the Korean Space Science Society
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• 1993.10a
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• pp.15-15
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• 1993

Revised Yale Isochrone(Green et al, 1987)과 Lee의 HB simulation data(LEE '||'&'||' Demarque 1990)을 이용하여 Park이 만든 CMD simulation program(Park 1983).에 쌍성을 첨가하면 CMD에 어느 정도의 영향을 나타내게 되는가를 조사하였다. MS, SGB와 RGB는 큰 변화가 없었으나, HB에서는 많은 변화를 나타내었다. 193919 S02401193919 ^x We have observed the emission of HC3N J= 4-3, 5-4 10-9 and 12-11 transitions toward the Sgr B2 central region in an area of 150"XISO" with resolutions of16"-48". The intensities and central velocities of line profiles show significant variations with positions. In contrast to the in tensities of the low J-level transitions which gradually increase from the central source toward the outside region the HC3N emission of the high J-level transition become stronger toward the central radio continuum source MO5. Systematic chainge in the radial velocity of each line profile occurs along north-south direction there are a few peaks in most line profiles, and these indicate that there not multiple velocity components along the line of sight. Distributions of excitation temperah at and column density which were estimated from the excitation calculations show the existence of a small(IxEpc),hot(Tex> SOK) core which contains two tempegatlue peaks at -15" east and north of MDS. The column density of HCaN is (1-3):n1014cm-2. Column density at distant position from MD5 is larger than that in the (:entral region. We have deduced that this hot-core has a mass of 10sR1 which i:s about an order of magnitude larger those obtained by previous studies.previous studies.

• Cross-Cultural Studies
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• v.21
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• pp.165-188
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• 2010

One of the things that should be done first in establishing the cosmic life culture is to reflect on the old human-oriented culture. If the cosmic life culture absolutizes everything except for humans according to the logic of reason, its foundation will weaken or eventually get lost. Separating humans from the universe is just like separating life from it. Given that all life, whether it is humans or the earth, originated from the universe, such an effort for separation merely values an individual life by excluding all life or whole life. When the human body and the cosmic chi' blood are not in an active flow, it means there is a problem with life. What is in the greatest need in such a case is the sincere human mind that follows the principle of cosmic life. It is like the sincerity found in the pasonri singer, who mellows all the hardships and difficulties in the world out and create songs out of them like the shadow. It is the pansori singer's shadow that changes the universe. It is only when the extreme force of human mind communicates with that of the universe that the cosmic life or cosmic life culture can be created. In that sense, it is urgent to create life out of the universe inside me and create a universe out of all life in and outside me. It is such a grave plan in human history in that it involves finding the "Sanal" which is the core of life living hidden inside the body whose life force gradually goes away or inside the universe, and creating the culture of Bokseung in which it bursts out. The most important thing in life is the flow, and the mankind is currently standing in the life flow of the massive universe's chaosmos. The greatest task the mankind is currently faced with is to think over how to deal with the period of Big Chaos in the massive universe's chaosmos reversely and establish the cosmic life culture anew.

• Journal of the Korean housing association
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• v.16 no.4
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• pp.1-7
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• 2005

In this study aim at searching for the basement residential planning of considering outdoor spaces. It look after research results, there should be necessary for the inflow of outdoor environment factors. This basement planning is core's area expending, or installing expended dry areas and acquiring side open spaces, installing arcades, installing atrium or court yard, utilizing maisonette spaces, activating pilotis on ground floors, openning main hall, earth sheltering method, etc. These should be improvement for easy step to change basement floors easily through underground floor extend, major repair, use change of present buildings and needs to the idea through architectural design competition.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.08a
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• pp.29-36
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• 2004

The paper describes recent experimental results on the development of Digital Magnetic Compass (DMC), which can provide smart automatic correction functions to the magnetic interferences. The design methodology of magnetic sensing circuit with ring-core fluxgate sensor is represented. The performance results of the sensing circuits are discussed with error analysis by polynomial regressions. As test results, the sensing circuit filtered only the second harmonic signal that is proportional to the direction of earth's magnetic field, and it leads to the obtainment of bearing information. In addition, the total residual errors of DMC can be analyzed by the adoption of polynomial regressions. It shown that the possibility of high precise DMC, in the future.

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.88-88
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• 1995

Microorganism are centIal core to biosphere sm1ainablity and biogeochemical cycles on this earth. Most of food, medical and pabamceutical new materials through biotechnology are derived from many kinds of microorganisms. Microorganisms are important resources of biotechnology. Beside these, micorbial diversity is key to explore the frontiers of knowledge about the strategies and limits of life. Through the micorotganisms, we can monitor the environmental changes and conditions. Moreover, the microorganismsms play a role in conservation and restoration of higher plants and animals. And we can get a lot of ecological, evolutionary knowledges from microbial models. In spite of these importances, the microbial diversity is not properly evaluted because of their unculturablity. Only 0.001 - 3 % of total bacteria in natural habitats are cultumble and the rest are viable but uncultumble. Only 3,100 species are listed up in the Bergey's Manual. Considering the symbisis and estimated numbers of insect are more than 800,000, the symbiotic microorganisms are about 1,000,000 species. Recently, by using the genetic and molecular technics, the microbial diversity is now unveiled. In this symposium, the genetic, species and ecological diversity will be given. given.