• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.5
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• pp.343-353
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• 2018

Ocean tides in Antarctica are not well constrained mostly due to the lack of tidal observations. Especially, tides underneath and around ice shelves are uncertain. InSAR (Interferometric Synthetic Aperture Radar) data has been used to observe ice shelf movements primarily caused by ocean tides. Here, we demonstrate that it is possible to estimate tidal constituents underneath the Sulzberger ice shelf, West Antarctica, solely using ERS-1/2 tandem mission DInSAR (differential InSAR) observations. In addition, the tidal constituents can be estimated in a high-resolution (~200 m) grid which is beyond any tidal model resolution. We assume that InSAR observed ocean tidal heights can be derived after correcting the InSAR data for the effect of atmospheric loading using the inverse barometric effect, solid earth tides, and ocean tide loading. The ERS (European Remote Sensing) tandem orbit configuration of a 1-day separation between SAR data takes diminishes the sensitivity to major tidal constituents including $K_1$ and $S_2$. Here, the dominant tidal constituent $O_1$ is estimated using 8 differential interferograms underneath the Sulzberger ice shelf. The resulting tidal constituent is compared with a contemporary regional tide model (CATS2008a) and a global tide model (TPXO7.1). The InSAR estimated tidal amplitude agrees well with both models with RMS (root-mean-square) differences of < 2.2 cm and the phase estimate corroborating both tide models to within $8^{\circ}$. We conclude that fine spatial scale (~200 m) Antarctic ice shelf ocean tide determination is feasible for dominant constituents using C-band ERS-1/2 tandem mission InSAR.

• Journal of the Korean Ceramic Society
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• v.48 no.4
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• pp.312-315
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• 2011

The effect of slurry composition and wafer flatness on a material removal rate (MRR) and resulting surface roughness which are evaluation parameters to determine the CMP characteristics of the on-axis 6H-SiC substrate were systematically investigated. 2-inch SiC wafers were fabricated from the ingot grown by a conventional physical vapor transport (PVT) method were used for this study. The SiC substrate after the CMP process using slurry added oxidizers into slurry consisted of KOH-based colloidal silica and nano-size diamond particle exhibited the significant MRR value and a fine surface without any surface damages. SiC wafers with high bow value after the CMP process exhibited large variation in surface roughness value compared to wafer with low bow value. The CMPprocessed SiC wafer having a low bow value of 1im was observed to result in the Root-mean-square height (RMS) value of 2.747 A and the mean height (Ra) value of 2.147 A.

• Ocean and Polar Research
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• v.30 no.4
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• pp.497-507
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• 2008

With the reduction of tidal currents by the closing of the Saemangeun 4th dyke, sedimentary environments on the Gunsan tidal flat, the nearest inner flat from the 4th dyke, has been severely changed, which might affect macrobenthic assemblages on the habitats. In order to investigate changes in macrobenthic community structure on Gunsan tidal flat, field surveys were seasonally conducted at seven stations from April 2002 to November, 2005. Sedimentary facies on the study area were shifted into muddominant facies. The fine sediment has been greatly deposited on the tidal flat with accumulation of organic materials after closing the water passage of 4th dyke section. These drastic variations in environments gave rise to change in macrobenthic community structure. Since the closure of the 4th dyke, the number of species of macrobenthos has gradually decreased. And the filter feeders and sand-favored species such as Urothoe convexa, Macrophthalmus dilatatus, Umbonium thomasi, and Mactra veneriformis have been replaced by the deposit feeders such as Macrophthalmus japonicus and Ilyoplax pingi. MDS ordination based on Bray-Curtis similarity from forth-root transformed species abundance data showed that the macrobenthic communities have passed through three succession stages from 2002 to 2005. During the third stage of 2005 opportunistic species such as Prionospio japonica, Heteromastus filiformis and Sinocorophium sinensis increased in population on the tidal flat.

• Asian Journal of Atmospheric Environment
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• v.4 no.3
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• pp.198-210
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• 2010

Precise analysis of local winds for the prediction of atmospheric phenomena in the planetary boundary layer is extremely important. In this study, wind profiler data with fine time resolution and density in the lower troposphere were used to improve the performance of a numerical atmospheric model of a complex coastal area. Three-dimensional variational data assimilation (3DVAR) was used to assimilate profiler data. Two experiments were conducted to determine the effects of the profiler data on model results. First, we performed an observing system experiment. Second, we implemented a sensitivity test of data assimilation intervals to extend the advantages of the profiler to data assimilation. The lowest errors were observed when using both radio sonde and profiler data to interpret vertical and surface observation data. The sensitivity to the assimilation interval differed according to the synoptic conditions when the focus was on the surface results. The sensitivity to the weak synoptic effect was much larger than to the strong synoptic effect. The hourly-assimilated case showed the lowest root mean square error (RMSE, 1.62 m/s) and highest index of agreement (IOA, 0.82) under weak synoptic conditions, whereas the statistics in the 1, 3, and 6 hourly-assimilated cases were similar under strong synoptic conditions. This indicates that the profiler data better represent complex local circulation in the model with high time and vertical resolution, particularly when the synoptic effect is weak.

• Journal of the Korean Graphic Arts Communication Society
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• v.2 no.1
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• pp.35-43
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• 1984

Shince the introduction of machine methods into industry a problem has existed which has never been adequately solved. .... That is to say, there is no difference between the essential qualities of Machine art and abstract art, which is the main style of fine arts in the present day. This problem has been discussed by John Ruskin, William Morris, Herbert Read. In this study, I discussed the artistic value in the modern graphic arts from the standpoint of Herbert Read on the machine art. According to the above-mentioned discussings, we can come to the conclusion as follows 1) The machine art lie at the root of abstract art, and whenever the final product of machine is designed or determined by anyone sensitive to formal values, that product can and does become an abstract work of art in the subtler sense of the term. 2) We must recognize that graphic design is a function of the abstract artist, and the abstract artist must be given a place in the graphic arts in which be is not already established, and his decision on all questions of design must be final. 3) Therefore, the graphic designer must have therough knowledge of graphic arts technology in order to give the artistic value to the objects of machine production.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1399-1406
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• 2009

In the internet broadcast, efficient and scalable mechanism of multicast is needed for the communication between groups. Furthermore, Optimization of the multicast tree is required to improve the performance of overlay multicast. This optimization is well-known as NP-complete. If a node in the tree has limited out-degree, a user who wants to join the group has to find parent user who has already joined. In this paper, the users who want to join the group need to setup their level using delay test from source node. And then new users can find candidate parent nodes effectively using ACK-SEND approach and take proper position by comparing level. The closer node of the user to root node should be located in lower level. Also, even if a barrier is caused, fast recovery will be guaranteed using ACK-SEND approach. Through this, the newcomer node can fine their location in the multicast tree and join the group fast and effectively.

• Journal of the Optical Society of Korea
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• v.20 no.4
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• pp.515-523
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• 2016

Spectral reflectance is sparse in space, and while the traditional spectral-reconstruction algorithm does not make full use of this characteristic sparseness, the compressive sensing algorithm can make full use of it. In this paper, on the basis of analyzing compressive sensing based on the orthogonal matching pursuit algorithm, a new algorithm based on the Dice matching criterion is proposed. The Dice similarity coefficient is introduced, to calculate the correlation coefficient of the atoms and the residual error, and is used to select the atoms from a library. The accuracy of Spectral reconstruction based on the pseudo-inverse method, Wiener estimation method, OMP algorithm, and DOMP algorithm is compared by simulation on the MATLAB platform and experimental testing. The result is that spectral-reconstruction accuracy based on the DOMP algorithm is higher than for the other three methods. The root-mean-square error and color difference decreases with an increasing number of principal components. The reconstruction error decreases as the number of iterations increases. Spectral reconstruction based on the DOMP algorithm can improve the accuracy of color-information replication effectively, and high-accuracy color-information reproduction can be realized.

• Food Science and Preservation
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• v.8 no.3
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• pp.258-263
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• 2001

This experiment was conducted to measure the physiological qualities and the chemical compositions of garlic bulb (Allium sativum L) stored in air and controlled atmosphere at 0$\^{C}$ for 4months. There were no significant differences in physiological qualities such as soluble solid, dry weight and firmness by O$_2$ and CO$_2$ concentrations during 4 months of storage. The surface color of garlic cloves changed toward more dark direction in Hunter color surface with storage. CA storage inhibited the sprout growth by 50% and had no significant difference in root growth. Garlic stored in CA showed lower level of pungency, especially CA of low oxygen concentration (1%) showed the lowest level of pyruvate. Garlic stored in high CO$_2$ concentration(20%) showed the lowest level of fructan concentrations and the highest free sugar concentrations.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.2
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• pp.1-16
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• 1991

In order to see the possible effect of the functional load-bearing after osseointegration of the titanium root form implant in dog a histologic study was conducted. One side of lower jaw was surgically prepared edentulousness and titanium implants were inserted. Some implants were functionally loaded through fixed detachable prosthesis and some are isolated and unloaded. The dog was sacrificed four months later and bone sections with implants were processed for histologic evaluation and the results were as follows ; (1) The bone to implant interface after four months of load bearing presented no mobility and no marginal bone loss radiographically and histologically. (2) The interface zone between compact bone and implant revealed a direct bone to implant contact and in some areas marrow tissue contacts were examined at the light microscopic level. (3) At the ultrastructural level the interface of surrounding compact bone matrix and implant, three types of superficial layers were found ; one with moderate electron dense amorphous granular substance layer, other with high electron dense fine granular substance layer, and another type of amorphous granular substance covered with high electron dense line of minute granules. (4) The osteoblasts in the marrow tissue neighboring implants and osteocytes in compact bone showed typical normal characteristics and in the marrow tissues some of lymphocytes and mast cells were observed. (5) The abscence of abnormal tissue reactions at a cellular level indicates a high degree of biocompatibility for the experimental titanium implant and basically no difference was found between functionally loaded and unloaded implants.

• Journal of Pharmaceutical Investigation
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• v.17 no.3
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• pp.111-126
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• 1987

Methyl methacrylate-butyl methacrylate copolymer (MMBM)-dibutyl phthalate (DBP) films were investigated as a potential topical drug delivery system for the controlled release of nitrofurazone. The kinetic analysis of release data indicated that drug release followed a diffusion-controlled granular matrix model, where the quantity released per unit area is proportional to the square root of time. DBP of several hydrophobic plasticizers selected was found to give the highest release of nitrofurazone. However, hydrophilic plasticizers such as propylene glycol and polyethylene glycol 400 had no controlled release properties and acceptable film formation. The effects of changes in film composition, drug concentration, film thickness, pH of release medium, and temperature on the in vitro release of nitrofurazone were analyzed both theoretically and experimentally. The release rate constant (k') was found to be proportional to DBP content, pH, and the temperature of release medium, but independent of film thickness, and drug concentration in a range of 0.1-0.4% by weight. The linear relationship was found to exist between the log k' and DBP content. The release of nitrofurazone from MMBM-DBP (8:2) films was found to be an energy-linked process. Two energy terms were calculated ; the activation energy for matrix diffusion was 13.45 kcal/mole, and the heat of drug crystal solvation was 27.26-29.34 kcal/mole. Observation of scanning electron micrographs and microscopic photographs showed that the incorporation of DBP in films increased markedly the particle size of nitrofurazone dispersed in the film matrix, comparing with the fine dispersion of nitrofurazone in pure MMBM film alone.