• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.5
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• pp.34-42
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• 1993

Due to the low loss, broadband and accurate short time delay properties of optical fiber, it has attracted as a delay medium for high speed and broad-band signal processing. In this paper, we consider the coherent optical fiber filter of lattice structure, which uses coherent light sources and consists of directional couplers and optical fiber delay elements.The differences between the optical fiber filter and the ordinary digital filter are 1) the coupling coefficients of directional couplers are restricted between 0 and 1. 2) the optical signal is divided into ${j\sqrt{a}}and\;{j\sqrt{1-a}}$ at the directional coupler. Considering these restrictions, the design formulae and condition of realibility for optical fiber filter of lattice structure which makes the optimal use of optical signal energy are derived.

• Journal of the Optical Society of Korea
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• v.19 no.6
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• pp.614-618
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• 2015

This paper described an off-axis head-mounted display system. It is composed of a 7-piece coaxial relay lens group and a freeform surface combiner. This configuration has a simple structure and a wide field of view (FOV). In this design, a freeform surface is chosen as the combiner, to simplify the structure and attain good image quality. We generated this freeform surface by considering both coordinates and normals of discrete data points. Moreover, we realize a coaxial structure in the relay lens group, which is compact and benefits from a loose tolerance requirement. The HMD system we finally realized has a 40° × 30° FOV and 15-mm exit pupil diameter.

• Korean Journal of Optics and Photonics
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• v.27 no.1
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• pp.32-40
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• 2016

The characteristics of an optical system vary depending on wavelength and ambient temperature. Based on the thin-lens approximation, we investigate the conditions for stabilizing an optical system against wavelength and temperature variations at the same time. The conditions are applied to designing a laser scanning system consisting of two lenses. The change in the effective focal length of the scanning system against wavelength and temperature variations is very small, as expected.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.51-54
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• 2005

Light Guide Plate (LGP) of LCD-BLU(Back Light Unit) is manufactured by forming optical pattern with $5\~100um$ in diameter on the LGP by means of sand blasting or etching method. However, in order to improve the luminance of LCD-LGP, the design of optical pattern has introduced UV inclined-exposure process in this study. This micro-optical pattern, which has asymmetric elliptical column shaped pattern, can change low viewing-angle to high viewing-angle, as well as it contribute to diffusion of light. As a result, this type of micro-optical pattern can introduce the highly luminance. The PR structure obtained in the stage of lithography has asymmetric elliptical column shape and it is processed into a micro-optical pattern. Optical design with this kind of micro-optical pattern, mold fabrication by electroplating and LGP molding with injection molding are under way.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.63-68
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• 2022

Two wavelength reconfigurable optical nodes are designed. One for 20km or shorter link length, and the other for up to 60km link length. While the first one requires no dispersion compensation, the latter needs dispersion compensation fiber included in the node, which requires additional optical amplifier to compensate the insertion loss of DCF. We calculate all the optical path losses in both cases using the typical value of optical components in the market to see the feasibility of the designed optical node. The minimum received power in the node is calculated to be -21.5dBm without DCF and -12.5dBm with DCF, respectively. These received powers are above the receiver sensitivity both for OC-48 and OC-192 according to the previous work.

• Journal of the Korean Ceramic Society
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• v.48 no.1
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• pp.40-45
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• 2011

In this study, the composition of optical glass for GMP(glass molding process) was designed with 'Design of Experiments' method. All the composition batch was performed by 'Create Factorial Design' method. Particularly, $SiO_2$, BaO and $Al_2O_3$ were chosen major parameters for investigating the effects of components on optical and thermal properties. BaO and $Al_2O_3$ strongly influenced on optical and thermal properties, respectively. Finally, the approximate values of desired optical and thermal values were obtained by microtuning of compositions. At the composition of $BaO:Al_2O_3:SiO_2$=10:4:48 (molar ratio), refractive index($n_d$) was 1.5833, coefficient of thermal expansion(CTE) was $104{\times}10^{-7}/^{\circ}C$.

• Journal of the Korea Fashion and Costume Design Association
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• v.17 no.2
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• pp.145-154
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• 2015

This study aims to identify the differences of body image when the stripe direction and width change of semi-tight skirt. The semi-tight skirt pattern was made using the standard size of a women in their 20s. 12 semi-tight skirt models combining 6 kinds of stripe directions and 2 kinds of stripe widths were made using CLO 3D virtual clothing system. The data was evaluated by 126 fashion design majors. The results were as follows; In accordance with the body image factor analysis of semi-tight skirt, three image factors were identified; whole body optical illusion, calf optical illusion and hip optical illusion. Among these factors, the whole body optical illusion factor is the most important factor. The body image depending on the stripe direction and width change of semi-tight skirt mostly showed the significant difference. In accordance with the analysis on the interaction effect of body image depending on the stripe direction and width change of semi-tight skirt, the whole body, calf and hip optical illusion factors showed the significance. The interaction of body image had independent influence on all factors of stripe direction and width. In particular, the interaction of stripe direction and width had the most significant influence on the whole body optical illusion.

• Journal of the Optical Society of Korea
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• v.19 no.6
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• pp.629-637
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• 2015

Compact system cameras (CSCs) are commonly used nowadays and feature enhanced video functions and thin yet light interchangeable lenses. They differ from digital single-lens reflex (DSLR) cameras in their lack of mirror boxes. CSCs, however, have autofocus (AF) speeds lower than those of conventional DSLRs, requiring weight reduction of their AF groups. To ensure the marketability of large telephoto zoom lenses with fixed f/2.8 regardless of field angle variation, in particular, light weight AF groups are essential. In this paper, we introduce a paraxial optical design method and present a new, large, telephoto zoom lens with f/2.8 regardless of the field angle variation, plus a lightweight AF group consisting of only one lens. Using the basic paraxial optical design and optimization methods, we fabricated a new and lighter zoom lens system, including a single-lens, lightweight AF group with almost the same performance.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.6
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• pp.75-80
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• 2017

The use of optical fiber makes it possible to transfer a large amount of data, thereby enabling a high-speed image transmission with a high response speed and a large number of frames. The need for an optical fiber HDMI System has grown in importance due to the rapid development of displays with large sizes and high-resolution images. In this paper, we have studied the structural design and FEM analysis of a 4C fiber guide for hybrid interconnection implementation. According to the structural analysis of the fiber guide, we have confirmed the safety of the design and we will make additional design changes to minimize the optical loss and fabricate a fiber guide for photoelectric composite HDMI in the future.

• Journal of the Korean Home Economics Association
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• v.35 no.1
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• pp.307-318
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• 1997

The purpose of this study is to survey differences of visual effects for location the york line. According to three types of body shapes(average, small & thin small & fat)for location of the york line We investigated the visual effects and optical illusion by slider and the results of data which analized by anova and duncan's multiple rannge are as follows. 1. In the A.V (average) body shapes design D1 was showed D1 was showed to be most remarkable in terms of optical illusion and design D2 was showed to be prefer in terms of visual sight. 2. In the S.T(small& thin) body shapes design D1 was showed to be most remarkable in terms of optical illusion but from the side view of looking thinness design D4 was showed to be nogative and from preference of visual sight design D4 was showed to be most negative. 3. In the S.F(small& fot) body shapes design D1 was showed to be most remarkable in terms of optical illusion and design D3 gained the bettle of superiority from the side view of looking tallness and design D3 was showed to be most negative in terms of the preference of visual sight.