Byung-Ju Kim

3D polygonal meshes watermarking using normal vector distributions

We proposed 3D polygonal meshes watermarking using normal vector distribution to robust against various attacks. The norm vector distribution of mesh is a consistent factor that is robust against various attacks. After calculating these distributions of 6 patches respectively, the same watermark bits are embedded into the same ordered bins in the distributions of 6 patches. The experiment shows that the watermark is imperceptible and robust against various attacks.

Occurrence of bacterial soft rot of onion plants caused by Burkholderia gladioli pv. alliicola in Korea

In the summer of 1999, disease symptoms of unknown origin were observed on onion bulbs in the fields and storage houses in Korea. Water soaked and very pale brown lesions appeared on the internal scales of diseased onion bulbs; they enlarged and extended to external scales with an associated sour smell. Bacterial soft rotting was more common than scale discoloration. This symptom was more pronounced at the neck end. From these lesions, we isolated two bacterial strains (designated CH1, CH2). Inoculation of bacterial isolates into onion bulbs yielded characteristic water-soaked symptoms which were distinguishable from those of the soft rot well known to onion growers. Inoculation of onion leaves and seed stalks produced white, oblong, slightly sunken and elongated spots. These symptoms started to appear 48 h after inoculation and leaves were completely killed within a week. Results of Gram stain, staining of flagella and biochemical tests identified these isolates as Burkholderia gladioli pv. alliicola. This was confirmed by pathogenicity, physiological and biochemical characteristics, an analysis of the 16S rRNA gene sequences and fatty acids profile. This is the first report of this bacterium in Korea.

Influence of Phosphorus Doping in the Active Layer with Deposition Time and Gas Flow Rate in a-Si:H Thin Film Transistor

Influence of phosphorus doping in the a-Si:H layer with various deposition time and phosphine gas flow rate in hydrogenated amorphous silicon thin film transistor (a-Si:H TFT) has been investigated. The a-SiN:H layer, the phosphorus doped a-Si:H layer and the n+ a-Si:H layer were deposited by plasma enhanced chemical vapor deposition (PECVD) using SiH4, PH3, Ar, H2 and NH3 gases. Proper phosphorus doping in the a-Si:H layer affected the channel of the a-Si:H TFT and improved the characteristics. Also, the field effect mobility was increased from 0.22 to 0.61 cm2/V·s. The characteristics of phosphorus doping in the a-Si:H TFT were investigated and compared with the conventional a-Si:H TFT.

Postprocessing algorithm in block-based coded images using wavelet transform and adaptive MLP

A novel postprocessing algorithm for reducing the blocking artifacts in block-based coded images is proposed using an adaptive neural network filter (NNF) in the wavelet transform domain. We use two characteristics, knowing the positions of the blocking artifacts in each band and discriminating between the horizontal and the vertical blocking artifacts using the wavelet transformed signals. At first, after performing a 3-level wavelet transform of the decompressed image, a different one-dimensional (1D) or 2D NNF is used to reduce the blocking artifacts according to the characteristic of each level. Experimental results show that the proposed algorithm produces better results than those of conventional algorithms, both subjectively and objectively.

Characterization of a-Si:H TFTs with Various Phosphorus Concentrations in a-SiN:H Layer

Characteristics of hydrogenated amorphous silicon thin-film transistors (a-Si:H TFTs) with various phosphorus doping concentrations in a-SiN:H layer have been investigated. The a-Si:H TFTs with a heterostructure of the phosphorus-contained a-SiN:H and intrinsic a-Si:H layers have been fabricated by a plasma enhanced chemical vapor deposition using SiH4, PH3, and NH3 gases. The mobility, the threshold and the surface roughness of the devices have been investigated and compared with the conventional amorphous silicon thin film transistors.