• Korean Journal of Materials Research
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• v.7 no.3
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• pp.203-212
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• 1997

This paper evaluated the feasibility of laser consolidation for improving the properties of the plasma coated layer, Further, the mechanim of the degradation sequence of the chrome carbide layer applied on the turbine blades was postualted. The laser consolidation could be successfully applied for improcing the surface properties of the plasma coated blade, if a proper condition was carefully chosen. The consolidated layer had erosion & corrosion resistance and vond strength superiro to those of the as-plasma coated layer. The properties of the consolidated layer were strongly dependent upon the degree of dilution, especially on the Fe pickup from the substrate. The degradation of the plasma coating layer was thought to be a reault of the repeating action of the solid particle erosion, corrosion penetration through the pores and oxide films formed along the interlayer surface and impact spalling.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.11c
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• pp.105-116
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• 1999

The Inchon International Airport site was formed by reclaimed soil from the sea. The average thickness of soft soil Is about 5 m and most of soft soils are normally consolidated or slightly over consolidated. There are many box culverts which are being constructed under the runways in the airfield. Sometimes, differential settlement can be occurred in the adjacent of box culvert or underground structures at the top layer of runway Soil compaction at very near to the structure is not easy all the time. Thus, one layer of geogrid was placed at the bottom of lean concrete layer for the concrete paved runway and at the middle of cement stabilized sub-base course layer for the asphalt paved runway. The length of geogrid reinforcement is 5m from the end of box culvert for both sides. The extended length of geogrid was 2m from the end of backfill soil in the box culvert. The tensile strength tests of geogrid were conducted for make sure the chemical compatibility with cement treated sub-base material. The location of geogrid placement for the concrete paved runway was evaluated. The construction damage to the geogrid could be occurred. Because the cement treated sub-base layer or lean concrete was spread by the finisher. The magnitude of tensile strength reduction was 1.16%~1.90% due to the construction damage and the ultimate tensile strength is maintained with the specification required. Total area of geogrid placement in this project is about 50,000 $m^2$.

• Journal of Ocean Engineering and Technology
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• v.11 no.3
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• pp.144-152
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• 1997

본 논문에서는 1년생 빙맥에 의하여 해양구조물에 작용하는 하중을 추정할 수 있는 모델을 제시하였다. 1년생 빙맥을 수면하부(keel), 수면상부(sail), 경화층(consolidated layer)의 3부분으로 나누어 각 부분에 의한 하중을 추정할 수 있는 방법을 논의하였다. 수면하부는 얼음조각(ice rubble)이 층으로 쌓여져 형성된 것이므로 수면하부에 의한 하중추정을 할 때 얼음조각을 선형 Mohr-Coulomb재료로 생각하여 토질역학(soil mechanics)의 이론을 사용하였다. 수면상부에 의한 하중도 토질역학 이론을 이용하여 추정하였으며 경화층에 의한 하중은 Korzhavin식을 이용하여 추정하였다. 제시한 모델을 이용하여 빙맥하중 추정에 미치는 인자들의 영향을 검토하였다.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.203-210
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• 2004

Consolidation properties were analysed by means of depositional environments. Depositional environments including geochemical properties, porewater chemistry, sediment structures, particle size distributions and carbon age dating were analysed using undisturbed samples retrieved successively from a boring hole in the study area. Laboratory oedometer tests and anisotropic consolidated triaxial tests(CKoUC) were performed to examine the overconsolidation phenomenons. Based on the carbon age dating results and profiles of geochemical properties, porewater chemistry, salinity and pH, it was founded that the upper silt/clay complex layer was deposited under marine condition while sand and clay layers were deposited under fluvial condition. Planar laminated structures of silts and clays were dominant in marine deposits. Although there was no clear evidences that geological erosion had been occurred in marine deposits, overconsolidation ratio obtained from oedometer tests were greater than unity. Stress paths of samples behaved similar to those of normally consolidated clays. Data plotted in stress state charts proposed by Burland(1990) and Chandler(2000) showed that the marine deposits were geologically normally consolidated. These apparent overconsolidations can be explained by the fabric and chemical bonding due to the difference of the rate of deposition.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.75-81
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• 2000

The anisotropy of soils has an important effect on stress-strain behavior. In this study, an attempt has been made to implement artificial neural network model for modeling the stress-strain relationship and predicting the undrained shear strength of normally consolidated clay with varying consolidation pressure ratios. The multi-layer neural network model, adopted in this study, utilizes the error back-propagation loaming algorithm. The artificial neural networks use the results of undrained triaxial test with various consolidation pressure ratios and different effective vertical consolidation pressure fur learning and testing data. After learning from a set of actual laboratory testing data, the neural network model predictions of the undrained shear strength of the normally consolidated clay are found to agree well with actual measurements. The predicted values by the artificial neural network model have a determination coefficient$(r^2)$ above 0.973 compared with the measured data. Therefore, this results show a positive potential for the applications of well-trained neural network model in predicting the undrained shear strength of cohesive soils.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.6
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• pp.434-442
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• 2015

In this paper, we propose an integrated spatial and view scalable video codec based on high efficiency video coding (HEVC). The proposed video codec is developed based on similarity and uniqueness between the scalable extension and 3D multi-view extension of HEVC. To improve compression efficiency using the proposed scalable multi-view video codec, inter-layer and inter-view predictions are jointly employed by using high-level syntaxes that are defined to identify view and layer information. For the inter-view and inter-layer predictions, a decoded picture buffer (DPB) management algorithm is also proposed. The inter-view and inter-layer motion predictions are integrated into a consolidated prediction by harmonizing with the temporal motion prediction of HEVC. We found that the proposed scalable multi-view codec achieves bitrate reduction of 36.1%, 31.6% and 15.8% on the top of ${\times}2$, ${\times}1.5$ parallel scalable codec and parallel multi-view codec, respectively.

• Journal of The Geomorphological Association of Korea
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• v.23 no.1
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• pp.17-33
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• 2016

Samples from newly exposed outcrop of sedimentary layers forming Jeongdongjin coastal terrace in Gangreung area are collected and analyzed to find the sedimentary environment. The site are located at the gentle hillslope of the terrace surface area. The height of the outcrop is about 8m and the altitude of it's highest part is 68~73m MSL. The lowest part of this out crop is the partly consolidated sand layer with gravel veneer within it. It is found that this part is not in-situ weathered sand stone through the OSL method. This sand layer is overlain by the gravel layer with sand matrix. The shapes of the gravels from this part are mainly 'platy', 'elongated', and 'bladed' by the index of Sneed and Folk(1958). In addition, mean roundness is not so high. It is sceptical to regard this part as marine sediments which are continuously exposed to erosional processes. The boundary between the lowest sand layer and gravel layer showing the abrupt change in forming material without any mixture or transitional zone, so gravels are seemed to deposited after some degree of consolidation of the lowest sand layer. In addition, the hight of the boundary between layers are changed by the place, so the surface of the partly consolidated sand layer is not flat and has irregularity on topography when it buried by gravels. Main part of this out crop is the poorly sorted coarse gravel(22.4mm) with sand matrix($1.36{\phi}$) layer with at least 2m thick covering the relatively fine gravels discussed above. Over 20% of particles have 'very platy', 'very elongated' and 'very bladed' shape and only less than 5% of particles have 'compact' shape, So this particles are also very hard to be regard as marine gravels which are abraded by marine processes. It can be concluded that this gravel layer formed by fluvial processes rather than coastal processes base on the form of the clast and sedimentary structure. The gravel layer is covered by fine($3{\sim}4{\phi}$) material layers of psudo-gleization which showing inter-bedding of red and white layers. Chemical composition of matrix and other fine materials should be analyzed in further studies. It is attempted to fine the burial ages of the sediment using OSL method, but failed by the saturation. So it can be assumed that these sediments have be buried over 120ka.

• Journal of Korean Society of Forest Science
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• v.23 no.1
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• pp.29-33
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• 1974

U-Reuk, a laureate musician in the days of King Jin-Heung, Silla Dynasty, built the Eui Rim Reservoir about 1,400 years ago. This was one of the oldest man-made reservoir. The embankment of the reservoir collapsed by the clumsy artificial drainage on August 19, 1972 when the heavy rainfall of 462 mm/day caused a dangerous overflow of the reservoir. The result of the study on the mystic ancient embankment techniques are as follows: 1. Sandy loam derived from the weathering of granite which is the most widely distributed rock type in the area, was used in the embankment. Large size logs (embankment core) of 30-50 cm in diameter were buried lengthwise along the embankment. 2. The six stocks of Pinus densiflora, 3 stocks of Quercus acutissima, 1 stock of Quercus variabilis and 1 stock of Popolus maximowiczii, altogether 11 stocks are identified. Forest types in the nearby area during the days of the reservoir construction seem to be includde a considerable number of Pinus densiflora, Quercus and Populus species. 3. The angle of repose of the earth materials is taken into account during the embankment. On top of the embankment double layers of clay (20-30 cm indepth) were spread and consolidated. Layer of litter of 20-40 cm in deep covered on the clay layer of the embankment completely, and another layer of clay was consolidated over the litter. Finally, a layer of stones of 10-30 cm in diameter and clay (yellow soil layer) toped the embankment. 4. At the lower part of the embankment clay layer was thicker and became thinner as it goes upwards. At every layer, soil was consolidated and burned. When embankment was completed, it was covered evenly with heavy clay, and finally it was topped with general soil. 5. The heavy clay layer on the inner slope of the embankment showed gray phenomena and litter remained raw humus layer. The clay layer functioned as rubber in the water, and raw humus layer prevented water from seepages. Thus, the embankment was solidly built in this way. 6. The ancient embankment techniques used soils conveyed from nearby area taking the angle of repose into account. Once embankment was completed, clay and litter layers were added to have a plasticity and to withstand the water pressure. 7. It is an excellent technique that the reservoir was constructed with least labor for maximum effects while the recent embankment techniques requires a large amount of labor.

• Journal of the Korean earth science society
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• v.24 no.8
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• pp.657-667
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• 2003

Deep-drilled core sampling and high-resolution seismic survey were carried out to identify a Holocene-late Pleistocene boundary in Gyeonggi Bay, western coast of Korea. Analysis of core sections revealed the existence of an oxidized and semi-consolidated sediment layer, Iying immediately below a Holocene horizon (Unit I) and being developed at the top of a late Pleistocene deposit (Unit II). The oxidized sedimentary layer (uppermost part of Unit II) is characterized by semi-consolidated, yellowish sediments showing signs of desiccation and alteration such as high N value, low water content, periglacial cryogenic structure, depletion of smectite, and high geochemical weathering index (Ba/Sr ratio). This feature, together with radiocarbon ages, suggests that the layer has formed as a result of prolonged subaerial exposure of Unit II sediments during the late Wisconsin sea-level lowstand, producing a regional unconformity. Such unconformitic-bounding surface corresponds to a prominent near-surface reflector (R), which is observed in seismic profiles obtained across the drilled-core sections in the study area. Consequently, the buried oxidized-sedimentary layer associated with the seismic reflector possibly plays a key horizon for the understanding of late Quaternary environmental changes as well as evidence of the emergence of the Yellow Sea shelf during the late Wisconsin sea-level lowstand.

• Journal of the Korean Geotechnical Society
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• v.20 no.5
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• pp.49-58
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• 2004

Consolidation properties of Shihwa deposits were analysed by means of depositional environments. Depositional environments including particle size distributions, sediment structures, geochemical properties, porewater chemistries and carbon age dating were analysed using undisturbed samples retrieved successively from a boring hole in the study area. Laboratory oedometer tests and anisotropic consolidated triaxial tests (CKoUC) for undisturbed samples were performed to examine the overconsolidation phenomena. Based on the results of analysis of depositional environments, it was found that the upper silt/clay mixed layer was deposited under marine condition while underlying sand and clay layers were deposited under fluvial condition. Planar laminated structures of silts and clays were dominant in marine deposits. Although there was no clear evidences that geological erosion had occurred in marine deposits, overconsolidation ratios of the upper marine samples were greater than unity Stress Paths of the upper marine samples behaved similarly to those of normally consolidated clays. Data plotted in stress state charts showed that the marine deposits were normally consolidated in geological meaning. These apparent overconsolidation of the marine deposits can be explained by the structures i.e. chemical bonding due to the difference of the rate of deposition, not by geological erosions and ground water fluctuations.