• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.1
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• pp.11-20
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• 2002

The world at the end of the $20^{th}$ Century has become "blue" Indeed, this past decade has witnessed a "blue rush" towards the development of violet-blue-green light emitting diodes (LEDs) and laser diodes (LDs) based on wide bandgap III-Nitride semiconductors. And the hard work has culminated with, first, the demonstration of commercial high brightness blue and green LEDs and of commercial violet LDs, at the very end of this decade. Thanks to their extraordinary properties, these semiconductor materials have generated a plethora of activity in semiconductor science and technology. Novel approaches are explored daily to improve the current optoelectronics state-of-the-art. Such improvements will extend the usage and the efficiency of new light sources (e.g. white LEDs), support the rising information technology age (e.g. high density optical data storage), and enhance the environmental awareness capabilities of humans (ultraviolet and visible photon detectors and sensors). Such opportunities and many others will be reviewed in this presentation.

• Korean Journal of Optics and Photonics
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• v.25 no.4
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• pp.169-192
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• 2014

In this paper, state-of-the-art digital holography and integral imaging have been introduced as practical three-dimensional imaging and display technology. Operational principles and recent research and development activities of these technologies have been discussed, as well as a vision of their future.

• Journal of Sensor Science and Technology
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• v.24 no.5
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• pp.311-318
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• 2015

The excess use and generation of various toxic gases from many industrial complexes and plant facilities have increased the possibility of leakage or explosion accidents, which can cause fatal damage to human beings in the wide range of neighboring area. To prevent the exposure to the fatal toxic gases, it is very important to monitor the leakage of toxic gases using gas sensors in real time. Various types of gas sensors, which can be classified as semiconductor, electrochemical, optical, and catalytic combustion types according to the operating principles, have been developed. In this review, the operation principles of gas sensors are explained and the performance of those sensors is compared. The state-of-the-art gas sensor technologies developed by research institutes or companies are reviewed also.

• Journal of Sensor Science and Technology
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• v.24 no.5
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• pp.281-286
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• 2015

The importance of air quality monitoring is rapidly increasing. Even though state-of-the-art air quality monitoring technologies such as mass spectrometry, gas chromatography, and optical measurement enable high-fidelity measurement of air pollutants, they cannot be widely used for portable or personalized platforms because of their high cost and complexity. Recently, personalized and localized environmental monitoring, rather than global and averaged environmental monitoring, has drawn greater attention with the advancement of mobile telecommunication technologies. Here, micro- and nano-technologies enable highly integrated and ultra-compact sensors to meet the needs of personalized environmental monitoring. In this paper, several examples of MEMS-based gas sensors for compact and personalized air quality monitoring are explained. Additionally, the principles and usage of functional nanomaterials are discussed for highly sensitive and selective gas sensors.

• ETRI Journal
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• v.41 no.1
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• pp.61-72
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• 2019

In this paper, we demonstrate the current concepts in holographic tomography (HT) realized within limited angular range with illumination scanning. The presented solutions are based on the work performed at Warsaw University of Technology in Poland and put in context with the state of the art in HT. Along with the theoretical framework for HT, the optimum reconstruction process and data visualization are described in detail. The paper is concluded with the description of hardware configuration and the visualization of tomographic reconstruction, which is calculated using a provided processing path.

• Journal of Conservation Science
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• v.32 no.2
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• pp.109-121
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• 2016

Mother-of-pearl turtle shell lacquerware refers to a decoration made of a mother-of-pearl, a turtle shell and metal wires. This lacquerware features bright color tone as it is produced by sprinkling metal powder over its entire surface. This study aimed to find out its material properties and characteristics by using an optical microscopy and conducting a SEM-EDS analysis on the cross section of lacquer coating. As a result, it was found that charcoal powder and soil powder were mixed for undercoating. Then a mixture of cinnabar lacquer and monoclinic arsenic sulfide mineral ($As_2S_3$) was coated on the undercoating and brass powder was sprinkled on top of it. Especially, a little amount of pigment was found on the lacquer layer, which is distinguished from the colors used for conventional lacquer patterns. In addition, it was also found that the cinnabar lacquer and monoclinic arsenic sulfide mineral were mixed together.

• Journal of Conservation Science
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• v.36 no.1
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• pp.47-59
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• 2020

Scientific analysis was conducted to identify the paint pigments used in the Buseoksa Josadang murals. optical microscopy(OM), X-ray fluorescence(XRF), XRF mapping, scanning electron microscopy-energy dispersive X-ray spectroscopy(SEM-EDS), and Raman spectroscopy were performed to examine the pigments. The results confirmed that the Josadang murals consist of two paint layers wherein the pigments were distinct for most colors. It was estimated that celadonite, white clay, red ochre, cinnabar and minium, synthetic green pigment containing tin and zinc paratacamite, or botallackite were used in the upper layer. In addition, bone white, celadonite, red ochre, azurite, cinnabar or vermilion, and gold were identified in the lower layer. In addition, as Zn and Sn were detected in the green pigments extracted from the top layer of the paint, it is believed that Josadang murals were repainted over the original paint layer at some point after the 17th century. In addition, white pigments containing calcium phosphate were found in all the colors in the bottom layer, which is the original paint layer. These results are significant because this is the first time that white pigments are found in Korean traditional paintings. Additionally, the information revealed about the pigments in this study will serve as areference for the pigments used in the Goryeo period.

• Journal of Korea Game Society
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• v.17 no.1
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• pp.7-16
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• 2017

The 3D game graphic technology has become an important factor in the contents field with the game contents development. In particular, game character technology provides a realistic technique and visual pleasure, as well as an intermediate step in the immersion of the game in which the game might create an optical illusion that enables the player to enjoy heroic adventure in the game. The high expression level of characters in 3D games is a key factor in the development process, with details and carefulness of the character setting work [3]. In this paper, we propose a character representative technique applied to mobile games using mathematical model of radiosity energy, spectral radiance model, and ray tracing model method using 3D unity game engine with sensible AI algorithm for game implementation. As a practical application to the game contents, it was found that the projection of the surface in the rendering process and the game simulation might change according to the lighting condition of the game content environment, so that the high quality of game characters was simulated.

• Journal of the Korea Furniture Society
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• v.25 no.2
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• pp.79-86
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• 2014

Furniture can be a product of design and is considered a form of a decorative art. Architectural works are often perceived as cultural symbols and as works of art. Korean traditional architectural form and wooden furniture were improved by adding up an organic coordination in the interior space. Furniture adds beauty of life by being coordinated with the interior space with its particular characteristic in the form of architectural structure. Architecture and furniture are also being improved in a more natural and diverse way. Therefore, in this research, from the choice of the location, Korean traditional architecture is considered to be coordinated with the nature, and the technical skill is lessened to express its beauty. There is a presence of elegance yet robust combination of simplicity and beauty. In addition, the traditional architecture and wooden furniture are completely expressed structurally with coordination of the outstanding design and solid structure according to the thrifty living in the Confucian ideas which influenced the Korean traditional society. The representative of Korean traditional architecture, Baeheulrim pillar, has worked as motive because of its visual comfort caused by optical illusion and formative elements. The small portable dining table (Soban) which reflects the characteristic of Korean unique tradition and the sensitivity of Koreans has been reinterpreted through the motive in this research. As a result, it has shown the possibility as the design element to change the aesthetic structure. In the modern society, cultural identity plays a vital role. Therefore, this research can be used as reference for the new concept of furniture - making. It could be a combination of modern people, lifestyle and living space by creating the Korean image suitable for the modern society.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.315-324
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• 2018

The study examines the effects of knowledge combination and of its interaction with technological change on the usefulness of inventions. We argue that inventing with knowledge components of prior art or with those in a variety of technical fields results in useful inventions, which changes after the emergence of dominant design because external actors' perception of which knowledge components are appropriate in current technological environments changes. Based on data from U.S. granted optical disc patents filed from 1992 to 2000, the results show that inventions with more new knowledge components relative to their prior art are less useful but that inventions with more diversified knowledge components are more useful. Also, the empirical findings show that the negative relationship between new knowledge components of inventions and their usefulness strengthens after dominant design emerges.