• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.110-115
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• 1998

Through the ISODATA method, the micro-landform of Julpo-Bay tidal flat was classified into mudflat, mixedflat, and sandflat using Landsat TM image. Each showed an apparent differences in its topographical characteristics and grain size composition. For example, mudflats are formed with flat faces and tidal channel of dissected gully. Its characteristics of grain size analysis that the grains have less than mean grain size 4 phi. Its sorting is bad (higher than 1 S.D.), and it showed strongly positive skewness. But sandflat is topographically flat without tidal channel. It has developed with ripple marks. According to the grain size analysis of deposits, the soil is coarse size with 90% of sand and its sorting is well(lower than 1 S.D.) Also, it showed strongly negative skewness. Mixed flat is in between mudflat and sandflat in its characteristics.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.3
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• pp.370-375
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• 1987

In this study, the Rayleigh fast fading simualtors encountered in channel modelling of mobile radio have been implemented and evaluated. Two models used for the fading environment were frequency composition of phase modulated signals and shaping spectrum of noise sources with filters. The spectrum chosen for our purpose is appropriate to an omnidirectional antenna. From results of the experiment with various parameters, we have obtained satisfying results which are closely agreed to theoretical values.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.242-242
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• 2012

Transparent oxide semiconductors are increasingly becoming one of good candidates for high efficient channel materials of thin film transistors (TFTs) in large-area display industries. Compare to the conventional hydrogenated amorphous silicon channel layers, solution processed ZnO-TFTs can be simply fabricated at low temperature by just using a spin coating method without vacuum deposition, thus providing low manufacturing cost. Furthermore, solution based oxide TFT exhibits excellent transparency and enables to apply flexible devices. For this reason, this process has been attracting much attention as one fabrication method for oxide channel layer in thin-film transistors (TFTs). But, poor electrical characteristic of these solution based oxide materials still remains one of issuable problems due to oxygen vacancy formed by breaking weak chemical bonds during fabrication. These electrical properties are expected due to the generation of a large number of conducting carriers, resulting in huge electron scattering effect. Therefore, we study a novel technique to effectively improve the electron mobility by applying environmental annealing treatments with various gases to the solution based Li-doped ZnO TFTs. This technique was systematically designed to vary a different lithium ratio in order to confirm the electrical tendency of Li-doped ZnO TFTs. The observations of Scanning Electron Microscopy, Atomic Force Microscopy, and X-ray Photoelectron Spectroscopy were performed to investigate structural properties and elemental composition of our samples. In addition, I-V characteristics were carried out by using Keithley 4,200-Semiconductor Characterization System (4,200-SCS) with 4-probe system.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.9
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• pp.685-689
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• 2009

Flash memory has several features such as low~power consumption and fast access so that there has been various research on using flash memory as new storage. Especially the Solid State Disk which is composed of flash memory chips has recently replaced the hard disk. At present, SSD adopts the multi-channel and multi-way architecture to exploit advantages of parallel access. In this architecture, data are written on SSD in a unit of a superblock which is composed of multiple blocks in which some blocks are put together. This paper proposes two schemes of selecting, segmenting and re-composing victim superblocks to optimize concurrent processing when a buffer flush occurs. The experimental results show that 35% of superblock- based write operations is reduced by selecting victims and additional 9% by composition of superblock.

• Journal of Broadcast Engineering
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• v.9 no.4 s.25
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• pp.371-383
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• 2004

In this paper we consider technological requirements to broadcast digital television signals using single frequency networks (SFN) in the Advanced Television Systems Committee (ATSC) transmission systems and propose equalization digital on-channel repeater (EDOCR) that overcomes the limitations of conventional digital on-channel repeaters (DOCRs). Since there are no forward error correction (FEC) decoder and encoder, the EDOCR does not have an ambiguity problem. In addition, since an adaptive equalizer in the EDOCR removes multi-path signals, additive white Gaussian noise (A WGN), and feedback signal due to low antenna isolation, the EDOCR may have good output signal quality with high power.

• 한국전산유체공학회:학술대회논문집
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• 2003.08a
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• pp.219-224
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• 2003

An analysis procedure for the MCFC channel flow has been developed to predict the fuel cell performance. As for the electrochemical reaction, among several chemical reaction models, one that fits the data best is adopted after a comprehensive comparative study. The Wavier-Stokes, energy, and species equations are solved to obtain the velocity, temperature and concentration fields for a specified average current density. The procedure is iterative as the local current density, or the reaction rate, is allowed to vary with the gas composition. A series of calculations are then carried out to examine the effects of gas flow rate, gas composition, gas usage rate, inlet gas temperature, and average current density on the fuel cell performance. The fuel cell characteristics, such as the temperature, current density distributions, and the concentration fields, for various operating conditions are presented and discussed.

• Macromolecular Research
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• v.15 no.4
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• pp.291-301
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• 2007

The rheological behaviors and morphologies of polylactide (PLA) and chemically modified plasticized starch (CMPS) blends were investigated. For this study, oscillatory shear flow measurements of the PLA, CMPS and their blends were performed. A scanning electron microscope (SEM) study was also conducted on the extracted extrudates of the blends. The morphology of the blend changed in relation to the composition: sphere-shaped CMPS disperse/continuous PLA, rod-like deformed CMPS phase/continuous PLA, a co-continuous structure with bridged CMPS long rods and PLA dispersed/continuous CMPS. The composition of the phase inversion could be estimated and closely coincided from the observed morphology experimental results. The rheological behavior of the blends, from oscillatory measurements, was found to vary in relation to the composition, and reflected the morphologies of the blends. PLA showed Newtonian flow behavior, while CMPS showed strong shear thinning behavior. The relationships between the morphology and rheological properties were observed in detail.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2055-2056
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• 2006

From composition transmitter is detached in indicator to individual load direction of 4 channels and adding up display by load cell indicator indication method of Bluetooth way is identifying marks.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2738-2740
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• 2005

From composition transmitter is detached in indicator to individual load direction of 4 channels and adding up display by load cell indicator indication method of Bluetooth way is identifying marks.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.4
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• pp.246-253
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• 2011

In this study, we investigated the effect of freshwater discharge on benthic community in Nakdong estuaries. The sediment was dominated by sand except few channels where heterogenetic sediment composition was observed. Sediment composition was rarely affected by freshwater discharge during the rainy season; however, organic content in the sediment slightly increased after the rainy season. Macrobenthic species composition differed spatially. For instance, species composition decreased after the rainy season near the barrage. Benthic community analysis revealed three groups, in which the first group was found between barrage and sand bars located at the mouth of estuary, the second group was observed outside the sand bars, and the last group was found in the channel. Opportunistic benthic species indicative of organic pollution, such as Sinocorophium sinensis, Magelona japonica, and Heteromastus filiformis, dominated areas close to the barrage. Organic pollution by freshwater discharge appears to be responsible for the emergence of opportunistic benthic species, and this influenced areas from the mouth of bay to sand bars. Outside the sand bars, freshwater discharge did not seem to have affected species composition.