• Current Optics and Photonics
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• 제4권1호
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• pp.23-30
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• 2020

This paper presents a new method for designing a lens system stable against chromatic variation at a specified wavelength. Conventional lenses are corrected for chromatic aberration, but the new method suppresses chromatic changes of the marginal ray in the image-side. By doing so, paraxial properties of the lens system are stabilized against chromatic variation. Since the new method is based on paraxial ray tracing, the stabilizing conditions against chromatic variation are given by recurrence formulas. However, there is an analytic solution for the case of a cemented doublet in the air. A stable doublet at 405 nm wavelength is designed and analyzed.

• 복식
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• 제59권4호
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• pp.67-81
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• 2009

This study aims to characterize the effect of different combinations of chromatic-achromatic colors and 1:2:3 area-ratio variation of stripe necktie, and gender on the image of male wearer. The experimental materials developed for this study are a set of stimuli and response scales. The stimuli consist of 84 color pictures manipulated with every combination of 12 different colors and 7 different area-ratio. The 7-point scale designed for visual evaluation of image formation included 26 bipolar adjectives. The subjects were 2016 undergraduate students in Gyeongnam, Seoul, Busan, and Daegu areas. The results of this study were as follows. The analyses of images of male wearer in terms of combinations of chromatic-achromatic colors and I :2:3 area-ratio variation of oblique stripe necktie reveal that the concerned factors are of five characteristic dimensions of youth-activity, ability, attractiveness, appeal, and warmness. In addition, it has been found that individual images of male wearer are affected by observer's gender as well as combinations of chromatic-achromatic colors and 1:2:3 area-ratio variation of stripe neckties and that those images vary with every combination of each factor. The study results are highly expected to be used as useful sources in developing necktie designs.

• 한국레이저가공학회지
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• 제2권2호
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• pp.18-26
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• 1999

An innovative real-time weld monitoring technique using chromatic filtering of the thermal radiation from a weld pool is developed. The thermal radiation from the weld pool is focused on an aperture and the transmitted thermal radiation is monitored at two wavelengths with high-speed single-element detectors. Due to the chromatic aberration introduced in the focusing optics, the transmittance curve of thermal radiation varies by the wavelength. Owing to this difference in the transmittance, the local variation of thermal radiation from the weld pool can be monitored by processing the two spectroscopic signals from two detectors. In this paper, the algorithms to monitor the laser power on the weld specimen and the focus shift we investigated and the performances of laser power and focus monitoring are shown for a pulsed Nd:YAG laser welding. The monitoring of the weld pool size variation is also discussed.

• 패션비즈니스
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• 제12권4호
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• pp.73-87
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• 2008

The main objective of this research was to investigate the characteristics of achromatic & chromatic color coordination of contemporary female fashion by reviewing 'pre-a-porter Collections' of four collections (i. e. cities) - Paris, Milan, New York, London - from the periods of 2002 S/S to 2006/7 A/W. The data was collected by reviewing 'pre-a-porter Collections' magazine and total 677 observations were made. Statistical analysis of frequency and also qualitative interpretation of achromatic & chromatic color coordination characteristics were completed. The main findings were; (1) The achromatic & chromatic color coordination was identified as one of most used color coordination in contmeporary women's fashion collections. (2) Black and white mainly used for achromatic color, and brown used the most often, then followed by blue, red, yellow, green and the others for chromatic color in achromatic & chromatic coordination of contmeporary women's fashion collections. (3) The characteristics of achromatic & chromatic color coordination of modern women's fashion collections from 2002 S/S to 2006/07 A/W showed various images according to chromatic colors and tone variation. The combination of achromaticand brown color variations produced an intelligent and sophisticated image. The soft or light chromatic color and chromatic color combination projected soft, feminine and subtle feeling, while the combination of vivid or strong chromatic color and achromatic color projected a clean and strong feeling through contrasting tones of clear and bright colors. The chromatic color of deep or dark tone and black combination demonstrated supernatural and gloomy image. (4)In all four collections, Paris showed most use of two color coordination and then followed by Milan, N.Y, and London. N.Y showed higher rate of using achromatic & chromatic color coordination, and then followed by Paris, London and Milan.

• 한국광학회지
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• 제31권6호
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• pp.295-303
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• 2020

NA 0.25, 10×이고, 파장 405 nm에서 파장변화에 대하여 안정한 Lister 대물렌즈를 설계하였다. 이 연구에서는 2매 접합렌즈에서 주어진 축상두께를 가지면서 파장변화에 대한 안정화 조건을 만족시키는 해를 찾는 방법에 대하여 연구하였으며, 이를 통하여 보다 쉽게 사용목적에 유용한 설계를 얻을 수 있다. 초기설계에서는 각각 독립적으로 안정화된 2개의 접합렌즈가 사용되었으며, 최적화에서는 전체 광학계에서 안정화 조건이 유지되도록 하였다. 최종설계에서는 기대한 바와 같이 파장 405 nm에서 파장에 따른 EFL, BFL, RMS wavefront error가 매우 적음을 확인할 수 있었다.

• Journal of applied mathematics & informatics
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• 제39권1_2호
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• pp.13-29
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• 2021

For a graph G = (V, E), a vertex coloring (or, simply, a coloring) of G is a function C : V (G) → {1, 2, …, k} (using the non-negative integers {1, 2, …, k} as colors). We say that a coloring of a graph G is injective if for every vertex v ∈ V (G), all the neighbors of v are assigned with distinct colors. The injective chromatic number χi(G) of a graph G is the least k such that there is an injective k-coloring [6]. In this paper, we study a natural variation of the injective coloring problem: coloring the edges of a graph under the same constraints (alternatively, to investigate the injective chromatic number of line graphs), we define the k- injective edge coloring of a graph G as a mapping C : E(G) → {1, 2, …, k}, such that for every edge e ∈ E(G), all the neighbors edges of e are assigned with distinct colors. The injective chromatic index χ′in(G) of G is the least positive integer k such that G has k- injective edge coloring, exact values of the injective chromatic index of different families of graphs are obtained, some related results and bounds are established. Finally, we define the injective clique number ωin and state a conjecture, that, for any graph G, ωin ≤ χ′in(G) ≤ ωin + 2.

• 패션비즈니스
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• 제9권1호
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• pp.21-33
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• 2005

The main objective of this research was to understand the characteristics of identical color coordination through the analysis of modern female fashion color coordination as they appear in the 'Collections'. Data collection of 2026 was done through review of '$pr\hat{e}t-\grave{a}$-porter Collections' of four cities; Milan, London, New York, Paris. Lastly, statistical analysis of frequency and $X^2$-test and also qualitative interpretation of identical color coordination characteristics were completed. The main findings were; The color coordination of modern women's fashion produces a unified theme, or monochromatic harmony, through the use and coordination of identical colors. The clear contrast of tones portrays a strong image especially in achromatic color coordination, and through the use of texture variation, monochromatic color coordination becomes even more compelling. The tone variation, observed most often in monochromatic color coordination was the black and white contrast, which enhances the simplicity and clarity. Within chromatic color combinations, tone on tone color coordination was achieved by varying brightness. Furthermore, the observation of Faux Camaeu indicates that the coordination of different textures is used often in identical color coordination. While achromatic colors can lead to a hard and rough feeling, it also is compensated through the use of varying textures. In addition, adding variety of textures can add subtle interests to the simplicity of white. Lastly, in all four collections, the chromatic identical color coordination was found more frequently than the achromatic. In Paris, N.Y. & London, the chromatic identical coordination was used more often than chromatic. Milan showed most use of achromatic coordination. The use of the tones showed similar trends in all four collections, with contrasting tone being used most often, followed by similar and identical tones.

• Journal of the Optical Society of Korea
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• 제4권2호
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• pp.94-99
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• 2000

Optical monitoring using the chromatic aberration of focusing optics is applied to auto-focus control in laser welding. The spectral transmittance of thermal radiation from a weld pool through an aperture depends on the wavelength of the spectral band and on the distance of the weld pool from the focusing optics. Its dependence has been used to monitor the focus shift in laser welding by measuring the spectral band signals filtered by the aperture. The difference between pulsed and continuous laser welding is analyzed. Furthermore, the dependence of the focus shift monitoring on the weld pool size variation is optimized to monitor the focus shift independently from the laser power change at the weld pool. The performance of the auto-focus control with chromatic filtering is presented for pulsed laser welding.

• 한국광학회지
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• 제28권2호
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• pp.68-74
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• 2017

특정한 파장대역에서 파장변화에 따른 굴절능의 변화를 1차, 2차 미분까지 보정하여 기준파장과 그 인근 파장 대역에서 굴절능의 변화가 매우 적도록 안정화된 광학계를 설계하는 방법에 대하여 연구하고, 이를 적용하여 회절한계의 시준렌즈를 설계하였다. 설계된 광학계는 파장 변화에 대하여 매우 안정하였고, 파장 360~410 nm 대역에서 유효초점거리의 변화가 0.002% 이내로 매우 적었다.

• 한국레이저가공학회지
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• 제4권2호
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• pp.29-38
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• 2001

A development of in-process and reliable monitoring system in laser materials processing is essential for successful applications toward the real industrial fields. It was known that optical signals induced by laser-matter interactions provide a good indication not only to monitor various defects but also to characterize and identify the process However there are still difficulties to implement the optical monitoring system in real fields since the system is susceptible to the spurious change of the signal affected by the variation of experimental conditions and environmental noises. In this article. a new type of optical monitoring technique named 'chromatic modulation technique' is described as a reliable, robust and sensitive monitor for the applications in laser materials processing in order to tackle the conventional problems in optical system.