• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.10
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• pp.1571-1575
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• 1989

Nonlinear beam coupling phenomena in photorefractive materials are analyzed as a function of the input beam intensities. Signal beam saturation and pump beam depletion are shown to be the intensity-dependent functions of these materials. Utilizing these phenomena in a photorefractive BaTiO3 crystal, optical logic processors such as AND, OR, NOT, etc., are implemented.

• Journal of Sensor Science and Technology
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• v.5 no.5
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• pp.85-95
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• 1996

Based on the transmission of coupled gap solitons in nonlinear periodic media, we present an all-optical switching scheme which has a novel architecture and principle. The proposed switch with an extremely small switching element can be realized on a semiconductor waveguide. We here investigate the switching performance with a GaAs waveguide in order to give criteria for the experimental realization of the all-optical switching phenomena. We also suggest a variation of an index-matching scheme to solve the technical problem such as the input-energy coupling into a periodic waveguide.

• Journal of the Korean earth science society
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• v.34 no.1
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• pp.51-58
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• 2013

An appropriate determination of time step is one of the important problems in atmospheric modeling. In this study, we investigate the sensitivity of numerical solutions to time step in a nonlinear atmospheric model. For this purpose, a simple nondimensional dynamical model is employed, and numerical experiments are performed with various time steps and nonlinearity factors. Results show that numerical solutions are not sensitive to time step when the nonlinearity factor is not influentially large and truncation error is negligible. On the other hand, when the nonlinearity factor is large (i.e., in a highly nonlinear regime), numerical solutions are found to be sensitive to time step. In this situation, smaller time step increases the intensity of the spatial filter, which makes small-scale phenomena weaken. This conflicts with the fact that smaller time step generally results in more accurate numerical solutions owing to reduced truncation error. This conflict is inevitable because the spatial filter is necessary to stabilize the numerical solutions of the nonlinear model.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.209-214
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• 2000

Shaking table tests were performed to investigate dynamic behavior of a three dimensional flexible rectangular liquid storage tank. Response characteristics to the three components of translational motion and three component of rotational motion were studied. The aluminium tank was exposed to the shaking high enough to make it behave in nonlinear range. Only very limited amount of the data have been processed yet. Very interesting phenomena on the effects of non-symmetry have been observed and presented. Test results that show nonlinear behavior under the high intensity shaking are reported.

• Journal of applied mathematics & informatics
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• v.2 no.1
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• pp.3-10
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• 1995

Nonlinear hyperbolic differenctial equations have been a subject of intense research in the field of gas dynamics due to many engineering problems associated with high-speed airplanes missiles materials processing etc. Recently phenomena known from gas dy-namics are found to occur also in the microeletronic devices such as MOSFET. Here a few interesting mathematical problems are presented along with future areas of research.

• Proceedings of the Optical Society of Korea Conference
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• 1991.07a
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• pp.5-8
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• 1991

New nonliner organic materials have been developed for all-optical signal processing. The organic materials possess many interesting features for this purpose. Unlike inorganic molecules the delocalized $\pi$-electron distribution and intramolecular charge transfer mevhanism allows certain organic molecules to respond highly anharmonically to an external field. In the present paper the origins of nonlinear phenomena, advantages of orgnic materials and structures of organic devices will be discussed.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.160-161
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• 2000

The 3rd order nonlinear properties show Optical bleaching (Saturation) and Reverse saturation in absorption aspect, whereas Self-focusing[3][4] and Self-defocusing in refraction aspect. Optical bleaching and Self-focusing phenomena of those properties in particular can be useful to make the optical beam spot size smaller for application on the higher optical storage density. (omitted)

• Current Optics and Photonics
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• v.6 no.6
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• pp.576-582
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• 2022

Plasmonic high-order harmonic generation (HHG) is used in nanoscale optical applications because it can help in realizing a compact coherent ultrashort pulse generator on the nanoscale, using plasmonic field enhancement. The plasmonic amplification of nanostructures induces nonlinear optical phenomena such as second-order harmonic generation, third-order harmonic generation, frequency mixing, and HHG. This amplification also causes damage to the structure itself. In this study, the plasmonic amplification according to the design of a metal-coated sapphire conical structure is theoretically calculated, and we analyze the effects of this optical amplification on HHG and damage to the sample.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1765-1770
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• 2005

Recently, particle filters have attracted attentions for nonlinear state estimation. In this approaches, a posterior probability distribution of the state variable is evaluated based on observations in simulation using so-called importance sampling. We proposed a new filter, Evolution Strategies based particle (ESP) filter to circumvent degeneracy phenomena in the importance weights, which deteriorates the filter performance, and apply it to simultaneous state and parameter estimation of nonlinear state space models. Results of numerical simulation studies illustrate the applicability of this approach.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.381-384
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• 2002

The free surface flow problem has been one of the most interesting and challenging topic in the area of the naval ship hydrodynamics and ocean engineering field. The problem has been treated mainly in the scope of the potential theory and its governing equation is well known Laplace equation. But in general, the exact solution to the problem is very difficult to obtain because of the nonlinearlity of the free surface boundary condition. Thus the linearized free surface problem has been treated often in the past. But as the computational power increases, there is a growing trend to solve the fully nonlinear free surface problem numerically. In the present study, a time-dependent finite element method is developed to solve the problem. The initial-boundary problem is formulated and replaced by an equivalent variational formulation. Specifically, the computations are made for a highly nonlinear flow phenomena behind a transom stern ship and a vertical strut piercing the free surface.