• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.582-585
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• 2004

Oyster fanning structures in tidal flats are well detected by SAR system. Each frame of these artificial structures is composed of two vertical and one horizontal wooden pole. We investigate characteristics of polarimetric features in the target structures. In this paper, the results of AIRSAR L-band POLSAR data and experiments in laboratory are discussed. The ratio of single bounce to double bounce scattering depends of vertical pole height, direction of horizontal pole to radar look direction, and incidence angle as well as sea surface condition. We have conducted laboratory experiments. According to target scale, Ku-band and targets downsized by scale of 10 are used. The results of the experiments are summarized as: i) total power of the backscattering is more affected by vertical poles than a horizontal pole; ii) and backscattering from a horizontal pole is sensitive to the relative radar look direction to target array. We conclude that water level can be effectively measured by using interferometric phase and backscattering intensity if vertical poles in the water are observed by L-band HH- or VV-polarization. Measurement of tide height can be further improved if double bounced components are separated from fully polarized SAR data.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.78.1-78.1
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• 2019

There are a huge number of faint objects that have not been observed due to the lack of large and deep surveys. In this study, we demonstrate that a deep learning approach can produce a better quality deep image from a single pass imaging so that could be an alternative of conventional image stacking technique or the expensive large and deep surveys. Using data from the Sloan Digital Sky Survey (SDSS) stripe 82 which provide repeatedly scanned imaging data, a training data set is constructed: g-, r-, and i-band images of single pass data as an input and r-band co-added image as a target. Out of 151 SDSS fields that have been repeatedly scanned 34 times, 120 fields were used for training and 31 fields for validation. The size of a frame selected for the training is 1k by 1k pixel scale. To avoid possible problems caused by the small number of training sets, frames are randomly selected within that field each iteration of training. Every 5000 iterations of training, the performance were evaluated with RMSE, peak signal-to-noise ratio which is given on logarithmic scale, structural symmetry index (SSIM) and difference in SSIM. We continued the training until a GAN model with the best performance is found. We apply the best GAN-model to NGC0941 located in SDSS stripe 82. By comparing the radial surface brightness and photometry error of images, we found the possibility that this technique could generate a deep image with statistics close to the stacked image from a single-pass image.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.2
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• pp.108-112
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• 2007

A cellulase (endo-${\beta}$-1,4-D-glucanase(E.C.3.2.1.4)) was isolated from the hepatopancreas of abalone Haliotis discus hannai by EST analysis. The abalone cellulase named HdEG compassed 1977 bp, including 195 bp in the 5'untranslated region, 1680 bp in the open reading frame which encodes 560 amino acid residues, and 92 bp in the 3'-untranslated region. The C-terminal region of the HdEG showed 44-52% identity to the catalytic domains of glycoside hydrolase family 9 (GHF9)-cellulases from arthropods and bacteria. The recombinant cellulase, pEHdEG was produced in E. coli with being fused with C-terminal His-tag. The expressed protein showed a single band (~62 kDa) on Western blotting which was consistent with the value (61,878 Da) calculated from the DNA sequence.

• Earthquakes and Structures
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• v.1 no.2
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• pp.147-162
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• 2010

The ground acceleration measured at a point on the earth's surface is composed of several waves that have different phase velocities, arrival times, amplitudes, and frequency contents. For instance, body waves contain primary and secondary waves that have high frequency content and reach the site first. Surface waves are composed of Rayleigh and Love waves that have lower phase velocity, lower frequency content and reach the site next. Some of these waves could be of more damage to the structure depending on their frequency content and associated amplitude. This paper models critical earthquake loads for single-degree-of-freedom (SDOF) inelastic structures considering evolution of the seismic waves in time and frequency. The ground acceleration is represented as combination of seismic waves with different characteristics. Each seismic wave represents the energy of the ground motion in certain frequency band and time interval. The amplitudes and phase angles of these waves are optimized to produce the highest damage in the structure subject to explicit constraints on the energy and the peak ground acceleration and implicit constraints on the frequency content and the arrival time of the seismic waves. The material nonlinearity is modeled using bilinear inelastic law. The study explores also the influence of the properties of the seismic waves on the energy demand and damage state of the structure. Numerical illustrations on modeling critical earthquake excitations for one-storey inelastic frame structures are provided.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.333-342
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• 2012

This paper presents a vowel onset point (VOP) detection method based on the human auditory system. This method maps the "perceptual" frequency scale, i.e. Mel scale onto a linear acoustic frequency, and then establishes a series of Triangular Mel-weighted Filter Bank simulate the function of band pass filtering in human ear. This nonlinear critical-band filter bank helps greatly reduce the data dimensionality, and eliminate the effect of harmonic waves to make the formants more prominent in the nonlinear spaced Mel spectrum. The sum of mel spectrum peaks energy is extracted as feature for each frame, and the instinct at which the energy amplitude starts rising sharply is detected as VOP, by convolving with Gabor window. For the single-word database which contains 12 vowels articulated with different kinds of consonants, the experimental results showed a good average detection rate of 72.73%, higher than other vowel detection methods based on short-time energy and zero-crossing rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5B
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• pp.517-529
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• 2011

In this paper, the parameters of the RTT (Radio Transmission Techniques) for SANET (Ship Ad-hoc NETwork), which is considered for the next generation maritime communication systems, are set up. A channel model has been analyzed based on the practical measured maritime wireless channel in VHF (Very-High Frequency) for SANET system. Also, by considering the frame structure including preamble, guard time and pilots for both single and multi-carrier systems, the BER (Bit Error Rate) performances are evaluated and analyzed in the aspects of channel compensation and channel coding techniques. Based on the simulation results, optimal modulation & coding schemes are suggested for SANET. That is, in single-carrier system by using differential modulation schemes, channel compensation is not necessary. However, channel coding is helpful to achieve additional gain. On the other hand, when 16-QAM modulation is employed in multi-carrier system, the implementation of both channel compensation and channel coding techniques show huge performance gain for various of K values, which are related to different maritime environments, and the rolling effects of wave.

• Journal of Microbiology and Biotechnology
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• v.20 no.10
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• pp.1403-1414
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• 2010

Aspergillus awamori BTMFW032, isolated from sea water, produced tannase as an extracellular enzyme under submerged culture conditions. Enzymes with a specific activity of 2,761.89 IU/mg protein, a final yield of 0.51%, and a purification fold of 6.32 were obtained after purification through to homogeneity, by ultrafiltration and gel filtration. SDS-PAGE analyses, under nonreducing and reducing conditions, yielded a single band of 230 kDa and 37.8 kDa, respectively, indicating the presence of six identical monomers. A pI of 4.4 and a carbohydrate content of 8.02% were observed in the enzyme. The optimal temperature was found to be $30^{\circ}C$, although the enzyme was active in the range of $5-80^{\circ}C$. Two pH optima, pH 2 and pH 8, were recorded, although the enzyme was instable at a pH of 8, but stable at a pH of 2.0 for 24 h. Methylgallate recorded maximal affinity, and $K_m$ and $V_{max}$ were recorded at $1.9{\times}10^{-3}$M and 830 ${\mu}Mol$/min, respectively. The impacts of a number of metal salts, solvents, surfactants, and other typical enzyme inhibitors on tannase activity were determined in order to establish the novel characteristics of the enzyme. The gene encoding tannase, isolated from A. awamori, was found to be 1.232 kb, and nucleic acid sequence analysis revealed an open reading frame consisting of 1,122 bp (374 amino acids) of one stretch in the -1 strand. In silico analyses of gene sequences, and a comparison with reported sequences of other species of Aspergillus, indicate that the acidophilic tannase from marine A. awamori differs from that of other reported species.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5162-5168
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• 2013

Hopping sequences of Time Hopped Ultra Wideband Impulse Radio (TH-UWB-IR) system are to mitigate multipath fading and to provide the multiple access chances for multi users. For the reliable communications, the same pulses are repeatedly transmitted for a bit duration based on hopping sequences. The proposed decoding scheme utilizes the intervals of inter-codes in a frame where the short interval between two pulses leads to the large interference by the multipath fading. For a single user case, the proposed method obtains 0.5dB gain over the conventional method at BER=$10^{-3}$. Decoding performance of repeated pulses can be increased using the property of the hopping sequences of multi users.

• The Plant Pathology Journal
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• v.16 no.5
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• pp.269-279
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• 2000

Alfalfa mosaic alfamoviruses(AIMV) were isolated from infected potato (Solanum tuberosum) and azuki bean (Paseolus angularis) in Korea. Two AIMV isolated from potatoes were named as strain KR (AIMV-KR1 and KR2) and AIMV isolated from azuki bean was named as strain Az (AIMV-Az). Each isolated AIMV strain was characterized by using their host ranges, symptom developments, serological relations and nucleotide sequence analysis of coat protein (CP) gene. Strains KR1, KR2, and Az were readily transmitted to 20 of 22 inoculated plant species including bean, cowpea, tomato, tobacco, and potato. AIMV-KR1 and KR2 produced the typical symptoms like chlorotic or necrotic spots in Chenopodium quinoa and Solanum tuberosum cv. Superior. AIMV-Az caused bright yellow mosaic symptom and leaf malformation in Nicotiana glauca, which were different from the common mosaic symptom caused by AIMV-KR1 and KR2. Electron microscope observation of purified virus showed bacilliform virions containing a single-stranded plus-strand RNAs of 3.6, 2.6, 2.0 and 0.9 kbp in length, respectively, similar in size and appearance to those of Alfamovirus. In SDS-PAGE, the coat protein of the two viruses formed a consistent band that estimated to be about 24kDa. The CP genes of the AIMV strains, KR1, KR2, and Az have been amplified by RT-PCR using the specific primers designed to amplify CP gene from viral RNA-3, cloned and sequenced. Computer aided analysis of the amplified cDNA fragment sequence revealed the presence of a single open reading frame capable of encoding 221 amino acids. The nucleotide and peptide sequence of viral CP gene showed that strain KR1, KR2, and Az shared highest nucleotide sequence identities with AIMV strain 425-M at 97.7%, 98.2%, and 97.2%, respectively. CP gene sequences of two strains were almost identical compared with each other. Altogether, physical, serological, biological and molecular properties of the purified virus.

• Fisheries and Aquatic Sciences
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• v.17 no.3
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• pp.325-337
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• 2014

To assess the functional structure of prepro-melanin-concentrating hormone (pMCH), we isolated and cloned pMCH (of-pMCH) mRNA from the brain of the olive flounder, Paralichthys olivaceus, and compared its amino acid sequence with those from other animals. In addition, to examine whether activation of the brain of-pMCH gene is influenced by background color, density, and feeding, we compared pMCH mRNA activities against different background colors (bright and dark) and at different densities (100% PCA and 200% PCA). To examine whether the pMCH gene is related with malpigmentation of blind-side skin and appetite, we compared pMCH gene expression between ordinary and hypermelanic flounders, and between feeding and fasting flounders. The of-pMCH cDNA was 405 bp in the open reading frame [ORF] and encoded a protein of 135 amino acids; MCH was 51 bp in length and encoded a protein of 17 amino acids. An obvious single band of the expected size was obtained from the brain and pituitary by RT-PCR. In addition, of-pMCH gene activity was significantly higher in the bright background only at low density (< 100% PCA) making the ocular skin of fish whitening, and in ordinary fish. However, the gene activity was significantly decreased in dark background, at high density (>200% PCA), and in hypermelano fish. These results suggest that skin whitening camouflage of the flounder is induced by high MCH gene activity, and the density disturbs the function of background color in the physiological color change. Moreover, our data suggest that a low level of MCH gene activity may be related to malpigmentation of the blind-side skin. In feeding, although pMCH gene activity was significantly increased by feeding in the white background, the pMCH gene activity in the dark background was not influenced by feeding, indicating that the MCH gene activity increased by feeding can be offset by dark background color, or is unaffected by appetite. In conclusion, this study showed that MCH gene expression is related to ocular-skin whitening camouflage and blind-skin hypermelanosis, and is influenced by background color and density.