• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.1053-1058
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• 1998

Poly(vinyl butyral)s (PVB) with different butyral content were synthesized from poly(vinyl alcohol)(PVA) and n-butylaldehyde with acid catalyst. Bound butyral unit in PVB was determined by elemental analysis. Synthesized PVBs were reacted with p-azidobenzaldehyde to give photosensitive polymer with azidobenzene group(PVB-AZ). Bound photosensitive azidobenzene group in PVB-AZ was determined by UV spectrophotometry. The photosensitivity of PVB-AZ was compared with that of PVB/2,6-bis(p-azidobenzylidene)cyclohexanone(BAC) photosensitizer mixture system by gray scale method. Photosensitivity of PVB-AZ was higher than that of PVB/BAC mixture system. The photosensitivity of PVB-AZ was dependent on the developer used due to the solubility of PVB-AZ in a developer solvent.

• The Journal of the Korea Contents Association
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• v.15 no.9
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• pp.11-20
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• 2015

Digital watermarking provides electronic means for proving the copyrights of distributed digital media copies. Research on digital watermarking for images is recently directed toward that for color images extensively used in real life, based on the substantial results in digital watermarking for gray-scale images. Color images have multiple channels, each of which corresponds to a gray-scale image. While there are some watermarking techniques for color images that just apply those for gray-scale images to one channel of the color images, the correlation characteristics between the channels are not considered in them. This paper proposes a zero-watermarking technique that makes keys via combining an image dependent watermark, created through comparing two channels of the color image and copyright watermark scrambled. Due to zero-watermarking, it does not change anything of cover(host) images. Watermark images are robust against some common attacks such as sharpening, blurring, JPEG lossy compression, scaling, and cropping.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.1
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• pp.125-132
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• 2024

Optical satellite images are being used for national security and collection of information, and their utilization is increasing. However, it acquires low-quality images that are not suitable for the user's requirement due to weather conditions and time constraints. In this paper, a deep learning-based conversion of image and colorization model referring to high-resolution SAR images was created to simulate the occluded area with clouds of optical satellite images. The model was experimented according to the type of algorithm applied and input data, and each simulated images was compared and analyzed. In particular, the amount of pixel value information between the input black-and-white image and the SAR image was similarly constructed to overcome the problem caused by the relatively lack of color information. As a result of the experiment, the histogram distribution of the simulated image learned with the Gray-scale image and the high-resolution SAR image was relatively similar to the original image. In addition, the RMSE value was about 6.9827 and the PSNR value was about 31.3960 calculated for quantitative analysis.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.2
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• pp.189-196
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• 2020

In general, fragmented files without signatures and file meta-information are difficult to recover. Multimedia files, in particular, are highly fragmented and have high entropy, making it almost impossible to recover with signature-based carving at present. To solve this problem, research on fragmented files is underway, but research on multimedia files is lacking. This paper is a study that classifies the types of fragmented multimedia files without signature and file meta-information. Extracts the characteristic values of each file type through the frequency differences of specific byte values according to the file type, and presents a method of designing the corresponding Gray-Scale table and classifying the file types of a total of four multimedia types, JPG, PNG, H.264 and WAV, using the CNN (Convolutional Natural Networks) model. It is expected that this paper will promote the study of classification of fragmented file types without signature and file meta-information, thereby increasing the possibility of recovery of various files.

• Childhood Kidney Diseases
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• v.6 no.2
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• pp.218-226
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• 2002

Purpose: The purpose of this study is to assess the ability of power Doppler sonography in the detection of acute pyelonephritis. Materials and Methods: We performed gray scale sonography, power Doppler sonography, and $^{Tc-99m}DMSA$ scintigraphy of the kidney in 80 patients with symptoms suggesting upper urinary tract infection. All imaging studies were obtained within 4 days. On $^{Tc-99m}DMSA$ scintigraphy, decreased radioactivity or photopenic lesions were considered indicative of acute pyelonephritis. Triangular areas of decreased perfusion identified on power Doppler sonography were considered as parenchymal lesions of acute pyelonephritis. The results of gray scale sonography and power Doppler sonography were retrospectively analysed and compared with those of $^{Tc-99m}DMSA$ scintigraphy which was given as the standards of reference. Results: For 40(85%) of the 47 patients with scintigraphy-proven acute pyelonephritis, power Doppler sonography diagnosed this condition on the correct side. The acute pyelonephritis which was not revealed by power Doppler sonography was observed in seven patients. Also, in three patients, false-positive indication of pyelonephritis was given by power Doppler sonography. Gray scale sonography showed positive findings in 23(49%) of 47 patients with positive findings on scintigraphy. Conclusion: Power Doppler sonography seems to be less sensitive than $^{Tc-99m}DMSA$ DMSA scintigraphy but significantly more sensitive than gray scale sonography for the detection of acute pyelonephritis in children. Power Doppler sonography shows promise as a noninvasive means of assessing renal cortical perfusion in children with clinically suspected acute pyelonephritis.

• The Plant Pathology Journal
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• v.21 no.3
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• pp.207-213
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• 2005

Cultural, morphological and pathogenic variation in Indian isolates of Ascochyta rabiei, the causal agent of blight of chickpea, was investigated. Fungal isolates representative of seven agroclimatic regions in north western plain zones (NWPZ) of India showed variation in colony colour as mouse gray with green hue, light mouse gray with slate gray centre and gray with dark brown centre, when grown on chickpea dextrose agar (CDA). Conidiomatal color of the isolates varied from brown to slate gray and black. The number of conidiomata and conidia formed on CDA ranged from 49.7 to 90.7 and $5.5\times10^4\;to\;3\times10^5cm^{-2}$, respectively. The size of conidiomata and conidia of A. rabiei isolates varied from $274\times232{\mu}m\;to\;156\times116{\mu}m$, and from $14.0\times6.2{\mu}m\;to\;10.7\times4.6{\mu}m$, respectively. Fourteen A. rabiei isolates from the seven agroclimatic regions of NWPZ were evaluated for their virulence on 180 chickpea genotypes in controlled environment. Cluster analysis based on the disease rating on a 1-9 scale indicated higher similarity coefficient (> 0.65) between isolates from different agroecological regions, while few isolates from the same region had less similarity. The 14 isolates were grouped into eight pathotypes at > 0.5 similarity coefficient. Sixteen genotypes were identified as probable differentials to distinguish A. rabiei isolates.

• 한국ITS학회:학술대회논문집
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• v.2007 no.10
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• pp.192-195
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• 2007

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.235-238
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• 2007

eMagin's unique OLED-on-silicon microdisplay technology is unique and is based on small molecule white OLED with color filters using a top emitter structure. This paper will present results of recent improvements in the technology including improved lifetimes and uniformity and will feature an SVGA resolution full color microdisplay that is 0.44 inches diagonal.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.76-79
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• 2007

Optical compensation films are widely used to enlarge viewing angle characteristics for LCDs. A new surface film with an inner light scattering layer was newly developed to improve gray scale inversion. This paper describes technologies regarding these films that enhance the viewing angle characteristics for LCDs.

• Journal of the Korea Society of Computer and Information
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• v.8 no.2
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• pp.57-63
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• 2003

In this paper, we propose the hardware architecture of a scale converter which is to convert a variety range of scale into a target scale and a time sequential color control driver for LOCS (Liquid Crystal On Silicon) micro display devices which are considered advanced micro display technology in the next generation. The driver has been implemented and tested with ASIC chips.