• Laser Solutions
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• v.4 no.2
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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.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2001.05a
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• pp.96-99
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• 2001

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.3 s.345
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• pp.27-31
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• 2006

Millimeter over Fiber (MMoF) technique modulates millimeter wave signal optically to transmit it through an optical fiber for long distances with small loss. MMoF system usually uses optical single sideband (OSSB) modulation scheme to reduce fiber chromatic dispersion and obtain high bandwidth efficiency. The optical link of MMoF system using OSSB is treated as a nonlinear amplifier, and the AM/AM characteristic function of the amplifier is a Bessel function of the first kind of order 1. In this paper, we investigate the performance of OFDM MMoF system considering nonlinearity of OSSB modulation. We estimate a power of the nonlinear distortion noise to analyze the theoretical bit error rate(BER), and perform a simulation to verify the theoretical BER.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.1
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• pp.11-17
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• 2004

We tried to design and manufacture a night scope which is used in the leisure sports field. The whole system consists of an IR light source part, an objective lens part, an intensifier tube part and an eye_piece lens part. We designed an objective lens part to the infinite object imaging optical-system with 80mm focal-length, 40mm effective-aperture and 14mm image-field-size of which the chromatic aberration is reduced by using materials of BK7 and FD4. The resolution of this system is about 25lines/mm at the 40% MTF value criterion. The eye_piece lens is adopted goods to be used commercially to save cost of production. The design technique which gets in this development will be utilized greatly in good developments of the dot, the sight and the day/night riflescope system at the hereafter.

• Journal of Korea Entertainment Industry Association
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• v.15 no.1
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• pp.63-73
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• 2021

This study aims to analyze music of Yoon-sang, as a part of musical research, which is the most fundamental approach among academic studies on Korean popular music. Yoon-Sang is a representative composer, who has gone through the 1980s to the present. The result of analysis of 21 songs created by Yoon-Sang showed that his songs are mostly characterized by tonal music, in which chord relationships develop focusing on keynotes. The reason why his music does not sound uniform pursuing stability is he properly added the progression of chromatic chords, based on diatonic chords and melodies. Dominant 7th chord and diminished 7th chord are used the most among diverse techniques adding chromatic colors. Along with these chords, chromatic intervals are used not only in chord progression but also in melodies. The successive, ascending or descending movement of the base line is his common composition and arrangement technique revealed in every song. One of formal changes with the stream of the times is that the number of measured in the pre-chorus and interlude that were of great importance in his songs of the 1990s decreased over time. With regard to harmonic changes, whereas modulation between parts was applied to his 2 songs created in the 2010s. Yoon-Sang's music had one strong tonality overall, but his music began to have more than two tonalities starting the 2010s, and this is a big variation in his music.