• The Journal of the Acoustical Society of Korea
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• v.22 no.2E
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• pp.78-86
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• 2003

We analyzed the measured acoustic field to explore the characteristics of a horizontal coherence in shallow water. Signal spatial coherence data were obtained in the continental shelf off the east coast of Korea using a horizontal line array. The array was deployed on the bottom of 130 m water depth and a sound source was towed at 26 m depth in the source-receiver ranges of 1-13 ㎞. The source transmitted 200 ㎐ pure tone. Topography and temperature profiles along the source track were measured to investigate the relationship between the horizontal coherence and environment variations. The beam bearing disturbance and array signal gain degradation is examined as parameters of horizontal coherence. The results show that the bearing disturbance is about ± 8° and seems to be affected by temporal variations of temperature caused by internal waves. The array signal gains show degradation more than 5㏈ by the temporal and spatial variations of temperature and by the down-sloped topography.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.295-298
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• 2010

To find out moving and dissipation patterns of laid floating object estuary this paper has focused on forming, changing and variation of the wind forced river plume. In steady state(without external force), river can be form a bulge and downcoast alongshore current on gently sloped continental shelf. Under the downwelling wind and downcoast meanflow those river plume's patterns are similar with the steady state case except enhancement of downcoast transportation. Under the upwelling wind condition bulge linearly move to the northwest with 45 angle due to Ekman transport. It's moving speed are linear with the strength of the wind stress but moving paths are independent of that. So, in this case, floating object will be dissipate to outside as move to the upcoast.

• The Journal of the Acoustical Society of Korea
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• v.20 no.5
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• pp.92-99
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• 2001

To measure temporal variability of long- range transmission in northern part of the East Sea of Korea, low frequency acoustic sources were deployed on the continental shelf 0.4km south of Cape Shultz near the port of Vladivostok during October 1999. The transmissions of the phase modulated signals were recorded by VLA moored on the northern slope of Ulleung-do. The measured signals were processed for the acoustic arrivals and their variability in time. The temporal signal processing involves pulse compression of the phase-encoded signal, time spread and temporal coherence processing. Variability of the ocean sound speed field in time scales of short period seems to be dominated by random fluctuations caused by sound speed perturbation due to the vertical displacements associated with internal waves.

• Ocean and Polar Research
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• v.27 no.2
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• pp.221-230
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• 2005

Recently there has been a rapid accumulation of knowledge of microbial life in cold and frozen ecosystems. This understanding has revealed the extensive diversity of psychrophilic prokaryotes. Cultivation-based and molecular-based surveys have been performed in Antarctic habitats ranging from glacial ice to continental shelf sediments. Results indicate that psychrophilic taxa permeate throughout the Bacteria while they represent a more mysterious element of diversity in the Archaea owing to a notable lack of cultured strains. In certain cold climate ecosystems the diversity of psychrophilic populations reach levels comparable to the richest temperate equivalents. Within these communities must exist tremendous genetic diversify that is potentially of fundamental and of practical value. So far this genetic pool has been hardly explored. Only recently have genomic data become available for various psychrophilic prokaryotes and more is required. This owes to the fact that psychrophilic microbes possess manifold mechanisms for cold adaptations, which not only Provide enhanced survival and Persistence but Probably also contributes to niche specialisation. These mechanisms, including cold-active and ice-active proteins, polyunsaturated lipids and exopolysaccharides also have a great interest to biotechnologists.

• Economic and Environmental Geology
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• v.29 no.6
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• pp.739-744
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• 1996

'Kite' is a newly developed single-channel seismic imaging system capable of producing high resolution three dimensional images of subbottom geology in one traverse of a survey region. The system consists of a horizontally towed hydrophone array and active source. The hydrophone array is towed axis perpendicular to ship direction and the airgun source at the end of the hydrophone array is excited at timed intervals during the progression. The construction of the three dimensional subbottom image was made simply by using conventional multichannel seismic reflection data processing techniques. Common source shot (CSS) gathers of the hydrophone traces are evaluated using Dix's equation for average interval velocity of each subbottom layer. From the interval velocity profile and the normal consolidation stress condition, values of shear modulus, porosity, and shear velocity are deduced from the chosen values of physical constants. The system has been successfully tested at several locations on the North Atlantic continental shelf.

• The Korean Journal of Petroleum Geology
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• v.10 no.1_2 s.11
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• pp.34-39
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• 2004

This article discusses stratigraphy and geological history of continental shelf area covering of offshore San-in to Tsushima islands. Geological data from 5 wells and detailed seismic surveys indicate that sediments in the studied area are divided into 4 stratigraphic groups ranging from Oligocene to Tertiary in age, namely X, H, K, and D groups in ascending order. The oldest X group of Oligocene time comprises paralic sediments including volcanics deposited in the initial stage of basin-formation. N group of mainly lower Miocene time consists of deep marine sediment, representing the highest stage of transgression. Sediments of the K group of middle Miocene time show distinct off-lapping depositional pattern during the basinfilling stage. The youngest D group covers these older groups unconformably. Strong deformation of sediments prior to the deposition of the D group formed many anticlinal structures. Five exploratory wells were drilled at the selected structures, where only minor gas shows were encountered. The area provides the enough palaeotemperature to mature the source rocks at moderate depth.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.4
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• pp.286-303
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• 2002

Korea Ocean Research and Development Institute (KORDI) has attempted moored current measurements since 1978. This note describes mooring types and failures of moorings deployed in coastal and continental shelf regions around Korea. Taut-wire U-type mooring lines and trawl-resistant bottom mounts have been mainly used in shallow seas. In order to avoid the failure of moorings in the shallow seas, it is needed to (1) design a proper mooring plan considering local mooring environments including fishing activities and (2) use adequate mooring equipments and parts considering mooring period, depth, and other factors that could affect the mooring unexpectedly.

• Animal Systematics, Evolution and Diversity
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• no.nspc2
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• pp.135-198
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• 1988

The present study on the classified and distribution of Korean marine archeogastropods is mainly based on the materials which were collected by the authors from July, 1979 to August, 1988 to 60 localities in the south Korean continental shelf. In addition to the 52 species and 8 subspecies of archeogastropods that have been reported from Korean waters, 9 species are found to be new to the fauna of Korea ; Diodora sieboldii (Reeve), Montfortula pulchra A. Adams, Colisella langfordi Habe, Notoacmea gloriosa Habe, Mesoclanculus ater (Pilsbry) , Cantharidus hirasei (Pilsbry), Guildfordia triumphans (Pilsbry), Tristichotrochus aculeatus (Sowerby), Homalopoma sangarense(Schrenck). The Korean marine archeogatropod fauna comprises 4 suborders, 5 superfamilies 10 families , 61 species and 8 subspecies. The authors listed the scienfic name of the korean archeogastropods in correct and described the unrcorded species from korea with keys to species and families.

• Strategy21
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• s.30
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• pp.177-199
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• 2012

As is generally known, the sovereignty dispute over the Senkaku Islands between China/Taiwan and Japan was triggered by a report commissioned by the UN in 1968, which reported the possibility of a substantial amount of petroleum and natural gas buried in the South China Sea. When the administrative authority over the Ryukyu Islands was transferred from the US to Japan in 1972, jurisdiction over the Senkaku Islands was also transferred. A dispute ensued between China (Taiwan) and Japan over the Senkaku Islands except during the period in which formal relations were established between the two states. This paper will take a look particularly at the events that occurred in the 2000's and discuss their recent trends and aspects of the dispute. Though China and Japan agreed to joint resource development in 2008, the agreed zone was a very small area adjacent to the Korea-Japan Joint Continental Shelf Development Zone, and the points of agreement have not been implemented. China has been developing four oil fields including Chunxiao in its waters adjacent to the median line asserted by Japan. However, China also has been excluding the participation of Japan, while Japan has been strongly objecting to the unilateral development of oil fields by China. If indeed the oil fields on China's side are connected past the median line asserted by Japan, then China's unilateral development will infringe upon the potential sovereign rights of Japan, thereby violating international law.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.4
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• pp.338-348
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• 1999

Physical properties of mudbelt sediments in the southeastern inner shelf of Korea are studied from 14 cores. Physical properties, compressional wave velocity, and sediment texture for core sediments are analyzed. The major source of sediment in the study area is the Nakdong River. Fine-grained sediments from the river are transported northeastward by coastal circulation and the Tsushima Current, resulting in a gradual northeastward increase in porosity and a decrease in wet bulk density and velocity. The trend matches well with the bathymetry. The mean grain size appears to be the most important variable to determine the physical properties and velocity. The variations of physical properties with burial depth are dependent more strongly on sediment texture than compaction and/or consolidation. Correlations between the physical properties and the sediment texture show slight deviations from those of the continental terrace sediment in the North Pacific and inner shelf sediment in the South Sea of Korea. The velocity is higher than that of the North Pacific and the South Sea sediments between these areas. This is probably due to differences in sedimentary, environment and mineral compositions. The higher sediment velocity in the study area may also be attributed to the escape of gas from pore space which decreases void ratio.