• Korean Journal of Optics and Photonics
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• v.16 no.5
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• pp.446-449
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• 2005

In a directional coupler, the design process requires repeated calculation of the characteristics of every changed structure, because it is generally difficult to expect the extinction ratio to be optimized over the entire variation of design parameters. In this paper, we systematically simulated the extinction ratio as a function of the design parameters, and analyzed the general tendency of that characteristic. In other words, we could find the generalized extinction ratio curve if the separation distance is normalized by the waveguide width. Here, the extinction ratio is shown to be increased as the normalized frequency (v) and the ratio (d) of the separation distance over the waveguide width were increased. For various structures with same ratio d, all corresponding extinction ratio curves as a function of v coincide with each other. We showed the usefulness of the generalized extinction ratio curve by applying it to the design and the fabrication of 1310/l550 nm demultiplexer, as it was convenient to design a shorter directional coupler with targeted extinction ratio from this curve.

• Science of Emotion and Sensibility
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• v.23 no.4
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• pp.21-32
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• 2020

The perception of a fashion product may vary depending on the texture and color of its material. Additionally, the product may appear differently in person versus on a digital screen. Therefore, in the present study, we sought to investigate the differences in visual sensibility evaluation between materials in person and on digital screens. In this study, three pairs of visual sensibility adjectives were tested for 60 samples selected as fashion materials. Fashion materials were divided into colors, embossings, and visual clarity categories. Results showed that each color had the same sense during in-person and digital evaluation. In terms of visual sensibility according to embossing, both in-person and digital evaluations of materials with embossings were found to have the same visual sense, whereas those without embossings looked different between in-person and digital evaluations. Assessments based on visual classification showed that both in-person and digital evaluations had the same sensibility. This study is meaningful in suggesting that when evaluating the visual sense of fashion material, the sensation for the digital screen versus in person may be different in some cases.

• Korean Journal of Heritage: History & Science
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• v.53 no.3
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• pp.24-41
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• 2020

The engraved line expression in metal crafts is a detailed technique of carving or decorating metal surfaces. This technique engraves a line using a tool on the surface of a metal craft. This technique was used extensively in articles made of various metal materials during the Goryeo Dynasty, and the range of patterns that could be expressed and the width of users was wide. In this paper, based on relics and literature, the concept of line representation of this engraving technique used in the metal crafts of the Goryeo Dynasty and the perceptions and terms of the Goryeo Dynasty were examined. In addition, the users engaged in this craft and the specific patterns and patterns of decoration were reviewed. Through these means, it was possible to confirm various aspects of a technique that was thought previously to involve just simple expression of lines using tools. In addition, through the literature, Geumseokmun Gate, and relics currently being transmitted, it was possible to confirm the utilization patterns of techniques used in various types of objects. Various uses have led to the combination with other metal craft techniques that were popular at the time, and while utilizing unique characteristics of the techniques, this maximized the molding of various patterns. In the meantime, it is true that the intaglio technique in metal crafts has not received much attention compared to the decoration techniques of other metal crafts, such as inlay, embossing, and openwork techniques in which decorative effects are maximized due to the recognition that the technique was used so widely in relics. However, the universality of the technique is premised on its wide use across all eras. As such, it was used in metal craft relics that reflect the various cultural characteristics of Korea and various cultural aspects that are currently passed down. On the one hand, technology has been passed down as a form of intangible heritage that embodies a longstanding craft culture which continues to the present in the fields of sculpture and intangible cultural properties. As such, the universality of Seongak contains many cultural meanings. In addition, the uniqueness of the technique is distinct, and it is deeply related to Goryeo, who was in charge of the use of technology and craftsmanship of the Joseon Dynasty and the metal craft technology that is currently handed down. I think research on future techniques should be continued in depth.