• The Journal of the Acoustical Society of Korea
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• v.5 no.1
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• pp.41-48
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• 1986

본 논문에서는 그레이디드 인덱스 다중모드 광섬유에 압력을 가함으로써 발생되는 마이크로벤딩 을 모드결합 이론으로 서술하였다. 그 이론에 의하여 모드결합이 최적으로 일어나는 정적벤딩을 통한 주기성을 얻어 시제품 광섬유 음향 트랜스듀서를 설계 및 제작하였다. 제작된 트랜스듀서의탐지 가능한 최소검출압력을 정적벤딩 실험을 통하여 계산하였으며, 아울러 제작된 광섬유 음향 트랜스듀서의 특성 을 실험하였다.

• Journal of the Optical Society of Korea
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• v.3 no.2
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• pp.55-63
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• 1999

For the precise analysis and design of LPFG's, a new method of generalized N$\times$N coupled-mode theory by section-wise discretization was proposed. This is applicable to the analysis for arbitrary grating structures, which can readily take grating nonuniformities and multimode couplings into account. Utilizing the method, several analyses of LPFG's were presented, and relationships between the grating structures and their spectral responses were discussed.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.32-33
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• 2001

근거리 통신망에서 데이터 전송량이 매우 증가함에 따라 근거리 통신에도 광통신을 적용하려는 연구가 활발히 진행 중이다. 광통신을 근거리 통신에 적용하려는 분야로는 랜, 댁내 망 (home network), 광 연결 (optical interconnect), 광 클럭 분배 (optical clock distribution) 등이 있다 그 중에 댁내 망의 경우 플라스틱 광섬유 (plastic optical fiber)를 이용하여 가정 내에 광통신을 적용하려는 연구가 진행 중이다. (중략)

• Journal of the Optical Society of Korea
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• v.10 no.2
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• pp.81-85
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• 2006

This study introduces an undefined self-imaging phenomenon, called here the pseudo-self-imaging phenomenon. The relative phases of the guided modes were used to discover how the pseudo-self-images are formed. The pseudo-self-image was found and measured experimentally. The experimental results showed that both the pseudo-self-image and the 0-dB self-image have similar intensity values and have opposite positions in the lateral direction.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.160-161
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• 2000

BK7 glass 기판에 Ag$^{+}$-$Na^{+}$ 이온교환법을 이용하여 Y-분리기를 제작하였다. Y-분리기는 하나의 입력으로 입사되는 광파워를 두 개의 출력단으로 분리하거나 합하는 기능을 수행하는 가장 기본적인 소자로서 이온 교환법을 이용하여 0.2dB/cm 이하의 전송손실을 유지할 수 있다. 또한 MMI (multimode interference)가 갖는 파장에 의존적인 동작 특성과는 달리 사용 파장에 덜 의존적으로 광 신호를 분기시킬 수 있다$^{(1-3)}$ . (중략)

• Journal of the Optical Society of Korea
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• v.4 no.1
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• pp.43-47
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• 2000

We studied experimentally a discrete random phase-code multiplexing technique for holographic data storage, which we believe can overcome some disadvantages of conventional random phase-code multiplexing adopting either a diffusion plate or a multimode fiber. Experimental demonstration is presented to show the potential usefulness and some characteristics of the discrete random phase-code multiplexing technique.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.90-91
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• 2003

정사각형 (sqaure) 구조 미소공진기는 Q값이 큰 4-bounce whispering gallery mode (WGM)가 존재 할 수 있고, 외부 도파로와 표면감쇠파 결합을 통해 상호작용할 때, 결합 길이가 매우 길어질 수 있어, 광통신용 Add／Drop Filter, 광집적회로 등의 저문턱 미소공진기 레이저 등의 광소자 분야에 적용하려는 연구가 최근 진행되고 있다. 그러나 단일 경계면을 갖는 사각 공진기는 공간 모드가 매우 많은 multimode 특성을 띄기 때문에 응용에 있어 단점이 된다. (중략)

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.364-364
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• 2008

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.1
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• pp.89-103
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• 2009

This study investigates the applicability of the time reversal concept in modem acoustics to the Lamb waves, which have been widely studied for defect detection in plate-like structures. According to conventional time reversal acoustics, an input signal can be reconstructed at an excitation point if an output signal recorded at another point is reversed in the time domain and emitted back to the original source point. However, the application of a time reversal process(TRP) to Lamb wave propagations is complicated due to velocity and amplitude dispersion characteristics of Lamb waves and reflections from the boundaries of a structure. In this study, theoretical investigations are presented to better understand the time reversibility of Lamb waves. In particular, the effects of within-mode dispersion, multimode dispersion, amplitude dispersion, and reflections from boundaries on the TRP are theoretically formulated. Simple numerical case studies are conducted to validate the theoretical findings of this study.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1516-1519
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• 1997

With disseminationof Distributed Control Systems(DCS), the huge amounts of process operation data could have been available and led to figure out process behaviors better on the statistical basis. Until now, the statistical modeling technology has been susally applied to process monitoring and fault diagnosis. however, it has been also thought that these process information, extracted from statistical analysis, might serve a great opportunity for process operation improvements and process improvements. This paper proposed a general methodolgy for process operation improvements including data analysis, backing up the result of analysis based on the methodology, and the mapping physical physical phenomena to the Principal Components(PC) which is the most distinguished feature in the methodology form traditional statistical analyses. The application of the proposed methodology to the Balst Furnace(BF) process has been presented for details. The BF process is one of the complicated processes, due to the highly nonlinear and correlated behaviors, and so the analysis for the process based on the mathematical modeling has been very difficult. So the statisitical analysis has come forward as a alternative way for the useful analysis. Using the proposed methodology, we could interpret the complicated process, the BF, better than any other mathematical methods and find the direction for process operation improvement. The direction of process operationimprovement, in the BF case, is to increase the fludization and the permeability, while decreasing the effect of tapping operation. These guide directions, with those physical meanings, could save fuel cost and process operator's pressure for proper actions, the better set point changes, in addition to the assistance with the better knowledge of the process. Open to set point change, the BF has a variety of steady state modes. In usual almost chemical processes are under the same situation with the BF in the point of multimode steady states. The proposed methodology focused on the application to the multimode steady state process such as the BF, consequently can be applied to any chemical processes set point changing whether operator intervened or not.