• Journal of the Korean Graphic Arts Communication Society
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• v.18 no.2
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• pp.55-68
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• 2000

Joint photographic experts group (JPEG) is a standard still-image compression technique, established by the international organization for standardization (ISO) and international telecommunication standardization sector (ITUT). The standard is intended to be utilized in the various kinds of color still imaging systems as a standard color image coding format. Because JPEG is a lossy compression, the decompressed image pixel values are not the same as the value before compression. Various distortions of JPEG compression and JPEG recompression has been reported in various papers. The Image compressed by JPEG is often recompressed by same type compression method in JPEG. In general, JPEG is a lossy compression and the quality of compressed image is predicted that is varied in according to recompression Q-factor. In this paper, four difference color samples(photo image, gradient image, gradient image, vector drawing image, text image) were compressed in according to various Q-factor, and then the compressed images were recompressed according to various Q-factor once again. As the result, this paper evaluate the variation of image quality and file size in JPEG recompression and recommed the optimum recompression factor.

• Proceedings of the Korean Printing Society Conference
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• 2000.04a
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• pp.17-24
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• 2000

The Joint Photographic Experts Group (JPEG) is a standara still-image compression technique, established by the International for Standardization (ISO) and International Telecommunication Standardization Sector (ITUT). The standard is intended to be utilized in the various kinds of color still imaging systems as a standard color image coding format. Because JPEG is a lossy compression, the decompressed image pixel values are nto the same as values before compression. Image of JPEG compression is often made to JPEG recompression at saving to apply JPEG compression of color image. In general, JPEG is a lossy compression and compression image is predicted to be varied image quality according to recompressed Q-factor. Various distortions of JPEG compression and JPEG recompression has been reported in previous paper. In this paper, we compress four difference color samples (photo image, gradient image, vector drawing image, text image) according to various Q-factor, and then compressed images are recompressed according to various Q-factor once again. As the results, we inspect variation of quality and file size of recompressed color image, and ensure the optimum recompression factor.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.1
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• pp.11-18
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• 2013

Eulsukdo located in the Nakdong Estuary plays important role in ecosystem and coastal wetland. There have been various changes in Eulsukdo up to now. Recently, we expect a great change of the western part of shoreline in Eulsukdo due to the floodgate construction but there is few databases. In this study, shorelines were digitized after we had produced the ortho-images by using aerial photos taken for 30 years(8 times). SCE, NSM and EPR were analysed by DSAS 4.2 program using vector data. In addition, the changes of shoreline were analysed in October 2011 from before Eulsukdo water gate construction to now by adding field surveying with VRS. The amount of years shoreline change is -0.34m/yr in 2009(before water gate construction) and -0.50m/yr in 2011(during the water gate construction), and the change trend shows an accumulation aspect.

• Polymer(Korea)
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• v.35 no.4
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• pp.350-355
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• 2011

A soluble polyamide containing photosensitive l,4-phenylenediacrylic acid (PDA) in main chain with biphenyl moiety was synthesized. The chemical structure of synthesized polyamide was investigated by means of $^1H$ NMR spectroscopy. The polymer was stable up to $280^{\circ}C$ and soluble in organic solvents, giving a good quality of thin films. The photoreaction of unpolarized LTV irradiated films was investigated by means of UV-vis absorption spectroscopy and FTlR spectroscopy, and liquid crystals (LCs) alignment property was examined by exposing to linearly polarized UV light (LPUVL) of 260~380 nm. The polyamide in film has excellent photoreactivity to unpolarized UV light. Direction selective photoreaction of PDA moiety in Lhe film was found to further induce nematic liquid -crystals to align along a perpendicular direction with respect to the electric vector of LPUVL, regardless of exposure energy of LPUVL. In addition, pretilt angle was measured by means of crystal rotation method. LPUVL-exposed polymer film induced the alignment of liquid-crystals (LC) with a pretilt angle of 0.2~$0.5^{\circ}$.

• Korean Chemical Engineering Research
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• v.45 no.5
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• pp.493-499
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• 2007

Polymeric hydrogel particles were fabricated to demonstrate the scale-up possibilities with the Particle Replication In Non-wetting Templates (PRINT) process. A permanently etched, specifically designed master was made on a silicon wafer using conventional photolithography, then reactive ion etching. The master and substrate were used repeatedly to make a large number of identical elastomeric perfluoropolyethers (PFPE) replica molds. The PFPE replica molds were used to fabricate and harvest individual, monodisperse micron-sized particles using the PRINT process. A water-soluble polymer adhesive was used as a sacrificial layer for harvesting particles. Particles were composed of biodegradable poly (ethylene glycol) diacrylate (PEG-diA), and aminoethylacrylate (AEM) and 2-acryloxyethyltrimethyl ammonium chloride (AETMAC) were added to them for improving the uptake of the cells. This study suggested PRINT used to produce the uniformed and shape specific biodegradable polymer is the effective technique for the non viral vector for the drug and the gene delivery.

• Journal of KIISE
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• v.42 no.4
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• pp.483-486
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• 2015

Security systems that use face recognition are vulnerable to spoofing attacks where unauthorized individuals use a photo or video of authorized users. In this work, we propose a method to detect a face spoofing attack with a video of an authorized person. The proposed method uses three sequential frames in the video to extract features by using Fourier Transform and Dense-SIFT filter. Then, classification is completed with a Support Vector Machine (SVM). Experimental results with a database of 200 valid and 200 spoof video clips showed 99% detection accuracy. The proposed method uses simplified features that require fewer memory and computational overhead while showing a high spoofing detection accuracy.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.32-37
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• 2005

We developed a numerical simulator in order to study the Super-RENS/ROM (Super REsolution Near-Field Structure, Read Only Memory) using 3-dimensional FDTD (finite difference time domain) method. The simulation can be performed by three steps. In the first step, we utilized the vector-diffraction theory to calculate the characteristics of incident laser beam from the object-lens to the surface of the disk. At the second step, we fed the calculated result as an input for the main FDTD simulations on the optical layers in the disk structure. After performed the FDTD simulations, we took near-to-far field transformation for the reflected signal, from the surface of the disk to the detector. Finally, we can get reflected signal at the photo-diode. Using this developed simulator, we were able to study about the reading signal from various disk structures as a function of a laser beam position. We calculated reading signals for various pit sizes for Super-ROM structure, and it is found that the simple optical diffraction theory can not explain the reading mechanism of Super-ROM, and more complicated temperature dependent physics must be involved.

• Fashion & Textile Research Journal
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• v.1 no.2
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• pp.119-126
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• 1999

The purpose of this study was to serve as a basis for the creation of new design. For attaining the purpose, an investigation was made into the actual condition or problems of domestic and foreign fashion design, and fashion design information was acquired from the Internet. Then, taking the acquired information as the basic data for merchandising, an attempt was made to work out an outline by using the Corel-Trace program, a widely-used computer software, and to modify it by using the Corel-Draw program. The findings of this study were as below: 1) The informations provided by domestic home-pages were largely made up of fashion news and articles on the trend of fashion, but included few of picture report. Almost all of them weren't developed into a database by item or detail. The foreign fashion design web-site were numerous in number, providing diverse information. They offered not only moving images or picture report on fashion show, leading models, photo gallery or fashion trend, but up-dated data everyday. 2) A way to create a design to meet a designer's target is recommended in this study. At first, the fashion information acquired through computer network would be handled by the Corel-Trace program. After Bitmap image would be converted into Vector image, that would be modified by the Corel-Draw program to create a design to suit a designer's target.

• Transactions of the Society of Information Storage Systems
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• v.2 no.2
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• pp.138-143
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• 2006

We developed a numerical simulator in order to study the Super-RENS/ROM (Super REsolution Near-Field Structure, Read Only Memory) using 3-dimensional FDTD (finite difference time domain) method. The simulation can be performed by three steps. In the first step, we utilized the vector-diffraction theory to calculate the characteristics of incident laser beam from the object-lens to the surface of the disk. At the second step, we fed the calculated result as an input for the main FDTD simulations on the optical layers in the disk structure. After performed the FDTD simulations, we took near-to-far field transformation for the reflected signal, from the surface of the disk to the detector. Finally, we can get reflected signal at the photo-diode. Using this developed simulator, we were able to study about the reading signal from various disk structures as a function of a laser beam position. We calculated reading signals for various pit sizes for Super-ROM structure, and it is found that the simple optical diffraction theory can not explain the reading mechanism of Super-ROM, and more complicated temperature dependent physics must be involved.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.8
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• pp.601-605
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• 2009

Recently, photo sharing and publishing based Social Network Sites(SNSs) are increasingly attracting the attention of academic and industry researches. Millions of users have integrated these sites into their daily practices to communicate with online people. In this paper, we propose an efficient face annotation and retrieval system under SNS. Since the system needs to deal with a huge database which consists of an increasing users and images, both effectiveness and efficiency are required, In order to deal with this problem, we propose a face annotation classifier which adopts an online learning and social decomposition approach. The proposed method is shown to have comparable accuracy and better efficiency than that of the widely used Support Vector Machine. Consequently, the proposed framework can reduce the user's tedious efforts to annotate face images and provides a fast response to millions of users.