• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.5
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• pp.430-434
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• 2001

We synthesized a new photo-crosslinkable polymer (polyimide (PI)-chalcone-biphenyl (BP)) and liquid crystal (LC) aligning capabilities for nematic (N) LC with obliquely polarized UV exposure on a photo-crosslinkable polymer were studied. The high pretilt angle in NLC was obtained by polarized UV exposure on a PI-Chal-BP surface for 3 min. The high pretilt angle generated in NLC is attributed to the biphenyl moieties and the photo-dimerized chalclone group of a photopolymer. Also, good thermal stability of a PI-Chal-BP were obtained by thermogravimetric analysis (TGA) measurement until 450$^{\circ}C$. Finally, good voltage-transmittance curves and response time were observed by UV exposure on a PI-Chal-BP surface for 3min.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.9
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• pp.770-775
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• 2000

A new photo-polymer material of the copoly (PM4Ch-ChMA), copoly (poly (4-methacryloyloxy)chalcone-cholesteryl methacrylate) for homeotropic alignment was synthesized and the electro-optical (EO) performance for the photo-aligned vertical-aligned (VA)-LC display (LCD) was studied. Good thermal stabilities of synthesized copolymer were obtained by TGA(Thermogravimetric Analysis) measurement. Good voltage-transmittance (V-T) and response time characteristics for the photo-aligned VA-LCD with polarized UV exposure in oblique direction($\theta$$_{i}$=30$^{\circ}$) on a copolymer-1 (2%) surfaces for 1 min were observed. but, light leakage in the off-state was observed. Therefore, we achieved excellent V-T and response time characteristics for the photo-aligned VA-LCD with UV exposure on a copolymer-3 (30%) surfaces for 3 min.n.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.647-650
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• 2009

In recent years, an understanding and concern about the Photo Realistic CG increased while the CG industry grew. The overall understanding of a system, an output and algorithm, and etc. are needed in order to implement the Photo Realistic CG. Moreover, for the realistic output on CG, the texture task that it is logical the various environment condition according to the physical environment and time, and etc.s has to show. For carrying out the Photo Realistic CG texture task, the extensity of a texture, the physical properties, a material, and an environment, the various access and the logical analysis are needed. Analyzed data reaches the direct affect to the final product for expressing. The realistic ancient history site, and the cultural inheritance and industrial product will be implemented with the ground of the research of the upper part in the imaginary realistic world.

• Journal of Sensor Science and Technology
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• v.21 no.5
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• pp.389-393
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• 2012

A chaotic oscillator with light controllability was designed. The proposed chaotic oscillator consists of a photo sensor, two phase clock driven MOS switches, nonlinear function blocks for chaotic signal generation. SPICE circuit analysis using a 0.35 um CMOS process parameters was performed for its chaotic dynamics. And we confirmed that chaotic behaviors of the circuit can be controlled according to light intensity. By SPICE simulation, chaotic dynamics by time waveforms, frequency analysis was analyzed. SPICE results showed that proposed circuit can make various light-controlled chaotic signals.

• Journal of the Semiconductor & Display Technology
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• v.13 no.2
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• pp.45-52
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• 2014

This paper proposes an efficient photo retrieval system that automatically indexes for searching of relevant images, using a combination of geo-coded information, direction/location of image capture device and content-based visual features. A photo image is labeled with its GPS (Global Positioning System) coordinates and direction of the camera view at the moment of capture, and the label leads to generate a geo-spatial index with three core elements of latitude, longitude and viewing direction. Then, content-based visual features are extracted and combined with the geo-spatial information, for indexing and retrieving the photo images. For user's querying process, the proposed method adopts two steps as a progressive approach, filtering the relevant subset prior to use a content-based ranking function. To evaluate the performance of the proposed scheme, we assess the simulation performance in terms of average precision and F-score, using a natural photo collection. Comparing the proposed approach to retrieve using only visual features, an improvement of 20.8% was observed. The experimental results show that the proposed method exhibited a significant enhancement of around 7.2% in retrieval effectiveness, compared to previous work. These results reveal that a combination of context and content analysis is markedly more efficient and meaningful that using only visual feature for image search.

• Journal of the Korean Society of Clothing and Textiles
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• v.43 no.1
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• pp.81-94
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• 2019

Social media is an essential part of everyday life in modern society and plays an important role in communicating the ideal body image. With the increased prevalence and high popularity of social media, the problems associated with the addictive use of social media have become a social issue. Utilizing social comparison theory, this study examined (1) the effect of appearance related photo activities on body satisfaction through appearance comparison and (2) the moderating effect of Instagram addiction in relationships among appearance related photo activity, appearance comparison, and body satisfaction. We tested the proposed relationships between research variables using multi-group structural equation modeling analysis on a sample of 346 young female Instagram users. The sample was divided into two groups of high and low addicted Instagram users. The results of this study showed that the appearance related photo activity positively influenced appearance comparison for both high and low addiction groups. For the high addiction group, the effect of appearance comparison on body satisfaction was not statistically significant; however, this relationship was significant and negative for the low addiction group. A significant moderating effect of Instagram addiction was found in the relationship between appearance related photo activity and appearance comparison.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.571-575
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• 2016

Photo responsive polymer(PRP) is well known for its photo deformation under UV light, and goes back to its original shape in visible light due to the photoisomerization of the azobenzene inside the PRP. In this paper, dynamic study of the vibration in PRP is discussed. In order to predict photo-deformation of the PRP a multiscale modeling is introduced which covers quantum level photo excitation, microscopic morphology, and macroscopic deformation of the PRP. A simple 1D beam model is introduced to model dynamic bending behavior of the PRP. Through fast Fourious transformation analysis, we identify that vibration frequency of the PRP can be controlled by light polarization angle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.943-944
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• 2012

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.55-56
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• 2008

The photo leakage currents of a conventional hydrogenated amorphous silicon(a-Si:H) thin film transistor(TFT) were investigated and analyzed in the case of illumination from various lightsources such as halogen lamp, cold cathode fluorescent lamp(CCFL) backlight, and white light emitting diode(LED) backlight The photo leakage characteristics showed the apparent differences in the leakage level and in the $I_{on}/I_{off}$ ratio in spite of the similar luminances of light sources. This leakage level is expected to be related to the wavelength of the lowest intensity peak from spectral analysis of light sources.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.4
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• pp.336-340
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• 2001

We have investigated the generation of pretilt angle and alignment stability for a nematic liquid crystal (NLC) with obliquely polarized UV exposure on the three kinds of photo-polymer. High pretilt angle of the NLC was obtained by polarized UV exposure on a PM4Ch surface for 1 min. But, the low pretilt angle of he NLC on a PVCi surface was observed. The pretilt angle generated is attributed ot the photosensitivity by the long side chaining of photo-polymer. Also, a good thermal stability of the three kinds of photo-polymer were obtained by thermogravimetric analysis (TGA) measurement until 300$^{\circ}C$. Finally, the good LC aligning capabilities using the photodimerization method were observed by annealing-treatment until 150$^{\circ}C$.