• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.249-250
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• 2011

• Journal of Conservation Science
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• v.34 no.6
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• pp.525-538
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• 2018

Myazedi Quadrilingual Stone Inscription of Myanmar, inscribed to the World Heritage List in 2015, is a rare historical artifact which has an exact date of inscription. It is a written record that displays the history, religion, and culture of Myanmar. Since the surface of the Stone Inscription has been rubbed with ink many times during the process of making printed copies for interpretation and academic research, it has developed a serious stain problem. Therefore, scientific analysis of the stain and research on the treatment for its removal have been conducted. In particular, an experiment was conducted on stain removal using laser cleaning and chemical treatment. The stains are mostly ink dirt, which accumulated from previous ink-rubbing processes. In order to conduct the experiment under similar conditions, a sample with similar stain has been reproduced, and a set of different conditions for treatment was applied to the sample to determine an effective solution. Laser cleaning was found to be effective in removing stains from most samples. However, chemical treatment showed different results. The physical friction method using ethanol provided the best result. In conclusion, laser cleaning is an effective universally-applicable technique but chemical treatment with laser cleaning can be considered an alternative method in certain situations.

• Journal of Information Technology Services
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• v.11 no.sup
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• pp.103-111
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• 2012

In epigraph field to study ancient scripts, alternative readability improvement technologies have been developed to replace existing rubbing method which has low resolution and causes surface pollution of heritages from the viewpoints of extraction process and used materials. Recently many methods which are based on analysis of pixel data for extracting outlines of the specific image have been developed with advancement of image processing techniques. But these methods are not applicable and the results are not satisfied in the damaged inscriptions which are weathered by wind and rain for a long time and in the narrowed one. In this paper laser scanning techniques which uses optical triangulation measurement principle are developed to minimize scanning error. The proposed techniques are consisted of 3 parts：(1) the understanding of optical triangulation measurement principle to find scanning guideline (2) determinations of points interval, scanning distance and scanning angle to guarantee scanning data quality (3) identification of valid point data area which will be used in registration process. The proposed character identification method contributed in decoding an ancient inscription on SeukBingGo in Kyungju.

• Journal of Conservation Science
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• v.28 no.1
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• pp.87-94
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• 2012

This study was focused on digital restoration and surface depth modeling applying the three-dimensional laser scanning system of the Haeundae Stone Inscription. Firstly, the three-dimensional digital restoration carried out acquiring of point cloud using wide range and precision scanner, thereafter registering, merging, filtering, polygon mesh and surveyed map drawing. In particular, stroke of letters, inscribed depth and definition appearing the precision scanning polygon was outstanding compared with ones of the wide range polygon. The surface depth modeling completed through separation from polygon, establishment of datum axis, selection of datum point, contour mapping and polygon merging. Also, relative inscribed depth (5~17mm) and outline by the depth modeling was well-defined compared with photograph and polygon image of the inscription stone. The digital restoration technology merging wide range and precision scanning restored the total and detailed shape of the Stone Inscription quickly and accurately. In addition, the surface depth modeling visibly showed unclear parts from naked eye and photograph. In the future, various deteriorations and surrounding environment change of the Stone Inscription will be numerically analyze by periodic monitoring.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.755-757
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• 2009

We developed a novel patterning method of organic light emitting materials using a laser-inscribed sacrificial layer for fabricating high-resolution pixels in organic light emitting displays (OLEDs). Our patterning process is capable of achieving high spatial resolution of about 10 ${\mu}m$. Moreover, it has no detrimental effect on the electrical properties of organic materials. This patterning approach is expected to be applicable for patterning and integrating a wide range of organic materials for organic electronic and optoelectronic devices.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.575-578
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• 2016

The thermal endurance of fiber Bragg gratings (FBGs), written with the aid of 193-nm ArF excimer laser irradiation on H₂-loaded Ge/B codoped silica fiber, and pretreated with a CO₂ laser and a subsequent slow cooling process, is investigated. These treated gratings show relatively less degradation of grating strength during the thermal annealing procedure. The thermal decay characteristics of treated and untreated fiber, recorded over a time period of 9 hours, have been compared. The effect on the Bragg transmission depth (BTD) and the center-wavelength shift, as well as the growth of refractive-index change during the grating inscription process for both treated and untreated fiber, are analyzed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2310-2316
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• 2016

We studied the effect of $Co^{60}$ gamma-radiation on the fiber Bragg gratings (FBGs) by irradiation time of UV Krypton fluoride (KrF) excimer laser among grating processing parameters. The FBGs were fabricated in a different UV laser irradiation time at 30, 60, 90, and 120 seconds using the same commercial Ge-doped silica core fiber (SMF-28e). It was exposed to gamma-radiation up to a high dose of 34.3 kGy at the dose rate of 106 Gy/min, and then it was analyzed radiation effects by measuring the radiation-induced change in the temperature sensitivity coefficient and Bragg wavelength shift. According to the experimental results, We confirmed that the UV laser irradiation period for grating inscription has a highly effect on the radiation sensitivity of the FBGs. The radiation-induced Bragg wavelength shift by the change of laser irradiation conditions showed a difference more than about 50 %.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.161-166
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• 2016

We studied the effect of $Co^{60}$ gamma-radiation on the FBGs by a variation of grating the fabrication parameters. The FBGs were fabricated in a different UV KrF laser intensity using the same boron co-doped photo-sensitive fiber and exposed to gamma-radiation up to a dose of 33.8 kGy. According to the experimental data and analysis results, We confirmed that the laser intensity for grating inscription has a highly effect on the radiation sensitivity of the FBGs and the radiation-induced Bragg wavelength shift by the change of laser process condition showed a difference more than about 30 %.

• Korean Journal of Optics and Photonics
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• v.21 no.6
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• pp.225-229
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• 2010

Laser-induced scatterer patterns in a light guide panel(LGP) have provided partially concentrated light distribution, especially near the light entrance of the LGP. Additional treatments for enhancing performance of the LGP, such as gradually increased processing depth, were also developed, but minor improvement was observed in the fabricated LGP. To solve this problem, we designed a revised scatterer pattern to be inscribed into the LGP using different laser processing depths and different separation distances between patterns. Performance feasibility of the proposed pattern was analyzed with simulation before laser inscription in the LGP. The LGP inscribed with the proposed scatterer patterns contributes improvements in luminance and uniformity of the LGP.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1980-1986
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• 2016

In this study, we studied the gamma-radiation effect of fiber Bragg gratings (FBGs) on the high temperature annealing condition after grating inscription using a KrF UV laser (248 nm). The FBGs were fabricated in a different annealing temperature using the same commercial Ge-doped silica core fiber (SMF-28e) and exposed to gamma-radiation up to a dose of 31 kGy at the dose rate of 115 Gy/min. The high temperature annealing procedure for grating stabilization was applied to change the radiation sensitivity of the FBGs. According to the experimental data and analysis results, the gratings that were stabilized at different temperatures at 100, 150 and $200^{\circ}C$ have clearly shown that exposure to higher temperatures increases their radiation sensitivity. The radiation-induced Bragg wavelength shift (BWS) was shown a difference of up to about a factor of two depending on the annealing temperature conditions of the gratings.