• The Journal of the Korea Contents Association
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• v.4 no.4
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• pp.123-131
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• 2004

Internet is absolutely contributed to information technology revolution nowadays. Internet services such as voice and data, etc. are provided home or small office via home gateway. The development of communication equipment via home gateway is implemented rapidly, and its product various. This paper presents the design and implementation of the VoIP equipment including the telephone function based on the embedded environment and being connected to the home gateway and the PC because of taking 2-ethernet LAN ports. As developing environment, the STLC1502 developed at ST Microelectronics as single chip solution, VxWorks as RTOS, and C language as coding mechanism are used. The verification of the developed systems for the voice test is carried out for the gatekeeper via Internet. The performance parameter is considered as the call processing capacity measuring the time of the call setup and clearing, and the data processing capacity for the file transfer. As a call setup and clearing is about 95ms, the call processing capacity is about 10 calls per second. The data processing capacity is 5.7Mbps in case of file transfer of server and client environment. Therefore the performance result is satisfied in the aspect of the call processing time and the data transfer time in Internet.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.5
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• pp.378-387
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• 2003

Digital watermarking is the technique that embeds invisible signalsincluding owner identification information, specific code, or pattern into multimedia data such as image, video and audio. Watermarking techniques can be classified into two groups; robust watermarking and fragile(semi-fragile) watermarking. The main purpose of the robust watermarking is the protection of copyright, whereas fragile(semi-fragile) watermarking prevents image or video data from illegal modifications. To achieve this goal watermark should survive from unintentional modifications such as random noise or compression, but it should be fragile for malicious manipulations. In this paper, an invertible semi-fragile watermarkingalgorithm for authentication and detection of manipulated location in MPEG-2 bit-stream is proposed. The proposed algorithm embeds two kinds of watermarks, which are embedded into quantized DCT coefficients. So it can be applied directly to the compressed bit-stream. The first watermark is used for authentication of video data. The second one is used for detection of malicious manipulations. It can distinguish transcodingin bit-stream domain from malicious manipulation and detect the block-wise locations of manipulations in video data. Also, since the proposed algorithm has an invertible property, recovering original video data is possible if the watermarked video is authentic.

• Journal of Engineering Education Research
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• v.8 no.1
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• pp.71-83
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• 2005

This paper presents an internet-based self-learning educational system which can be enhancing efficiency in the learning process of Java language. The proposed self-learning educational system is called Java Web Player(JWP), which is a Java application program and is executable through Java Web Start technologies. Also, three important sequential learning processes : concept learning process, programming practice process and assessment process are integrated in the proposed JWP using Java Web Start technologies. This JWP enables the learners to achieve efficient and interesting self-learning since the learning process is designed to enhance the multimedia capabilities on the basis of various educational technologies. Furthermore, internet-based on-line voice presentation and its related texts together with moving images are synchronized for efficient language learning process. Also, a simple and useful Java compiler is included in the JWP for providing language practice environment such as coding, editing, executing and debugging Java source files. Finally, repeated practice can make the learners to understand easily the key concepts of Java language. Simple multiple choices are given suddenly to the learners while they are studying through the JWP and the test results are displayed on the message box. This assessment process is very essential to increase the learner's academic capability.

• Korean Journal of Microbiology
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• v.54 no.1
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• pp.69-70
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• 2018

Erwinia pyrifoliae is a Gram-negative bacterium causing black shoot blight in apple and Asian pear trees. E. pyrifoliae strain EpK1/15 was isolated in 2014 from an apple twig from the Pocheon, Gyeonggi-do, South Korea. In this study, we report the draft genome sequence of E. pyrifoliae EpK1/15 using PacBio RS II platform. The draft genome is comprised of a circular chromosome with 4,027,225 bp and 53.4% G + C content and a plasmid with 48,456 bp and 50.3% G + C content. The draft genome includes 3,798 protein-coding genes, 22 rRNA genes, 77 tRNA genes, 13 non-coding RNA genes, and 231 pseudo genes.

• Journal of Life Science
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• v.26 no.11
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• pp.1259-1268
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• 2016

In this study, we investigated antimicrobial peptide from the acidified muscle extract of Mytilus coruscus, which mostly inhabits China, Japan, and Korea, to develop a natural product-derived antibiotics substitution in terms of its abuse and restriction. Antimicrobial peptide was purified by $C_{18}$ reversed-phase high-performance liquid chromatography and was detected as having a molecular mass of 6,701 Da by MALDI-TOF/MS. The N-terminal amino acid sequence of the purified peak was obtained from edman degradation, and 20 identified residues shown 100% identity with the N-terminus region of sperm-specific protein and protamine-like PL-II/PL-IV precursor of Mytilus californianus. We also identified 60 open-reading frame (ORF) encoding amino acids with 183 bp of purified peptide based on the obtained amino acid residues. The amino acid sequence of ORF showed 100% and the nucleotide sequence revealed 97.2% identity with the protamine-like PL-II/PL-IV precursor of Mytilus californianus. Synthesized antimicrobial peptide showed antimicrobial activity against gram-positive bacteria, including Bacillus cereus (minimal effective concentration [MEC], $20.8{\mu}g/ml$), Bacillus subtilis (MEC, $0.2{\mu}g/ml$), Streptococcus mutans (MEC, $0.2{\mu}g/ml$), gram-negative bacteria including Pseudomonas aeruginosa (MEC, $5.7{\mu}g/ml$), Escherichia coli (MEC, $2.6{\mu}g/ml$) and fungi, Candida albicans (MEC, $56.3{\mu}g/ml$). In addition, synthesized peptide showed stable activities under heat and salt conditions against gram-positive and gram-negative bacteria, but was inhibited by salt against only C. albicans. With these results, isolated peptide from M. coruscus could be an alternative agent to antibiotics for defending against pathogenic microorganisms, and helpful information to understand the innate immune system of marine invertebrates.

• Journal of Life Science
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• v.27 no.11
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• pp.1276-1289
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• 2017

This study isolated and purified the antimicrobial peptide McSSP-31 from an acidified hemocyte extract of a Mytilus coruscus. The antimicrobial peptide was purified by using a $C_{18}$ reversed-phase high-performance liquid chromatography (HPLC). The peptide was determined to be 3330.549 Da by matrix assisted-laser desorption ionization time-of-flight mass spectrophotometer (MALDI-TOF/MS). The N-terminus of a 14 amino-acid sequence was identified as P-S-P-T-R-R-S-T-S-R-S-K-S-R by Edman degradation method. The acquired sequence showed a 93% similarity with the sperm-specific protein Phi-1, which is from M. californianus. The identified open-reading frame (ORF) of peptide was 306 bp encoding 101 amino acids, which was analyzed by rapid amplification of cDNA ends (RACE), cloning and sequencing analysis. We compared the full sequence with other known proteins that reveal the sperm-specific protein Phi-1 (93.5%) of M. californianus. Synthesized antimicrobial peptide (McSSP-31) showed antibacterial activity against gram-positive bacteria including B. subtilis, S. mutans, S. aureus and gram-negative bacteria including E. coli, K. pneumoniae, P. mirabilis, P. aeruginosa and fungi, C. albicans. Also, synthesized peptide showed strong antibacterial activity against antibiotic-resistant strains, including S. aureus. The cytotoxicity of the peptide was determined by using the HUVEC human cell line. The peptide did not exhibit any significant cytotoxic effects on the normal human cell line, and it had very low hemolytic activity with flounder hemoglobin. The results demonstrated that peptide purified from the hemocyte of a M. coruscus exhibits antibacterial activity against various bacteria and has the potential to be an alternative antibiotic agent.

• Journal of Life Science
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• v.28 no.11
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• pp.1301-1315
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• 2018

We purified an antimicrobial peptide from the acidified hemocyte extract of Mytilus coruscus by $C_{18}$ reversed-phase high-performance liquid chromatography (RP-HPLC). The peptide was 4041.866 Da based on matrix-assisted laser desorption ionization time-of-flight mass spectrophotometer (MALDI-TOF/MS) and the 25 amino acids of the N-terminus sequence were identified. Comparison of this sequence of the purified peptide with the N-terminus sequences of other antimicrobial peptides revealed 100% identity with the mytilin B precursor of Mytilus coruscus. We also identified a 312 bp open-reading frame (ORF) encoding 103 amino acids based on the obtained amino acid residues. The nucleotide sequence of this ORF and the amino acid sequence also revealed 100% identity with the mytilin B precursor of Mytilus coruscus. We synthesized two antimicrobial peptides with an alanine residue in the C-terminus, and designated them mytilin B1 and B2. These two antimicrobial peptides showed antimicrobial activity against gram-positive bacteria, including Bacillus cereus and Streptococcus parauberis (minimal effective concentration, MECs $41.6-89.7{\mu}g/ml$), gram-negative bacteria, including Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Providencia stuartii, Pseudomonas aeruginosa, and Vibrio ichthyoenteri (MECs $7.4-39.5{\mu}g/ml$), and the fungus Candida albicans (MECs $26.0-31.8{\mu}g/ml$). This antimicrobial activity was stable under heat and salt conditions. Furthermore, the peptides did not exhibit significant hemolytic activity or cytotoxic effects. These results suggest that mytilin B could be applied as alternative antibiotic agent, and they add to the understanding of the innate immunity of hard-shelled mussels.