• Journal of Advanced Marine Engineering and Technology
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• v.18 no.1
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• pp.32-40
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• 1994

The radiative heat transfer analysis in particle layer has an inherent difficulty in treating the governing integro-differential equations, which are derived from the remote effects. Most of the existing analyses are limited to the one dimensional system, taking into account only absorption or isotropic scatting of solid particles. Fortunately, a new Monte Carlo Simulation method is recently developed to analyse multidimensional radiative heat transfer in particles with anisotropically scatting. By this method, the present study analyses the radiative heat transfer in dispersed particles through the numerous droplets in the liquid droplet radiator to develop a technique of liquid droplet radiator. Consequently, knows that the radiative heat flux in particle layer is influenced by exitinction coefficient, optical thickness and surface area of particles in the system.

• Journal of the Korean Society for Library and Information Science
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• v.35 no.3
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• pp.35-54
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• 2001

The Libraries are face to difficult of academic journal subscription for the increasing price of journal and the increasing number of journal. Bibliographic citation analysis is one of method of evaluating the use of a journal collection. This study is used bibliographic use and scatting of foreign academic journal in Library and Information Science found in doctorial dissertation of graduate students in Seoul city, for serve to complement another method of journal evaluation. Journal selection and cancellation may be done on the basis to dispersion of journal citation to usefulness of journal subscription in the library budget. But the library should not rely on one single evaluation technique, it should take advantage of combination technique.

• Journal of the Korean Graphic Arts Communication Society
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• v.13 no.1
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• pp.93-104
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• 1995

Liquid crystal-polymer composite(LCPC) films promising new materials for both projection displays and vision product. LCPC films consist of a continous liquid crystal phase embedded in a three- dimensional network of polymer matrix. The liquid crystal in these LC phases can be elecrtrically switched giving rise to an opaque scattering off-stats and a transparent, non-scatting on- stats. In this work. a premixture is composed of LC, UV-curable monomer and photonitiator. LCPC films are formed by photopolymerization induced phase separation from this premixture. In conclusion, structure and electro-optical properties of LCPC films strongly depends on the selection of monomer, LC content and curing rate.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.627-628
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• 2008

We have studied the optical performance of flexible polymer network liquid crystal (PNLC) films at various bending states. Different measurement setups, wide and narrow opening angles of detector, were used to collect scatting light of PNLC films. The optical and dynamic properties of bent PNLC implied the change of LC domains.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.117-120
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• 2000

When analyzing the scatting problem of multi-layered structures using closed-form Green's function, one of the main difficulties is that the numerical integrations for the evaluation of diagonal matrix elements converge slowly and are not so stable. Accordingly, even when the integration for the singularity of type e$\^$-jkr//${\gamma}$/, corresponding to the source dipole itself, is performed using such a mathod, this difficulty persists in the integration corresponding to the finite number of complex images. In order to resolve this difficulty, a new technique based upon the Gaussian quadrature in polar coordinates for the evaluation of the two-dimensional generalized exponential integral is presented. Stability of the algorithm and convergence is discussed. Performance is demonstrated for the example of a microstrip patch antenna.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1297-1301
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• 2007

The indoor air quality guideline of public transportation means was prepared recently. therefore we consider a countermeasure for the indoor air quality improvement of public transportation means. In this work, air-cleaner with roll filter system which developed alternative of indoor air quality guideline. The develpoed roll filter system is two function. the first function harmoniously circulated to heating and cooling air through HVAC system and secondary function removed PM(particluatie matters) which re-scatting to passenger's movement and suppled from outdoor air. Filter media of roll filter system select optimum electret mesh filter out of many filter media. Selected filter media was performanced tests of pressure drop, collection efficiency and dust holding capacity. Finally developed roll filter system was performanced bench test.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.2
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• pp.331-337
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• 1994

The scatting problem by E-polarized plane wave with obique incidence on a tapered resistive strip grating with zero resistivity(perfectly conducting) at strip-edges is analyzed by the method of moments in the spectral domain. Then the induced surface current density on the strip is expanded in a series of Chebyshev polynomials of the second kind. The expasion coefficients are calculated numerically in the spectral domain, the numerical results of the geometric-optical reflection coefficient for the tapered resistivity in this paper are compared with those for the existing uniform resistivity. And the position of sharp variation points in the magnitude of the geometric-optical reflection coefficient can be moved by varying the incident angle and the strip spacing, It is found out that these sparp variation points are due to the transition of higher mode between the propagation mode and the evanescent mode.

• Journal of the Korea Society of Computer and Information
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• v.9 no.4 s.32
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• pp.13-18
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• 2004

In this paper, we proposed a new digital watermarking technique. It uses frequency domain of discrete wavelet transform(DWT). watermarking technique is one of the most important tools for DRM(Digital Right Management) We proposed a new algorithm watermark insertion and detection. This technique cleats the watermark sequence using the edge image, spread spectrum technique and DWT. We tested the technique with various attacks. and found that it satisfies the watermarking evaluation criteria. Cox similarity measurement value is more than 6 on the Lena image and PSNR is more than 40dB on JPEG, Collusion. Clopping and Scatting. By the result, we proved that the new technique satisfies the requirement of Digital contents distribution, which are undeletablility tenacity, statistical undetectablility.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.4
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• pp.411-421
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• 2002

The accurate analysis of ultrasonic wave propagation and scattering plays an important role in many aspects of nondestructive evaluation. A numerical analysis makes it possible to perform parametric studies, and in this way the probability of detection and reliability of test results can be improved. In this study, a finite element method was developed for the analysis of ultrasonic fields, the accuracy of results was checked by solving several representative problems. The size of element and the integral time step, which are the critical components for the convergence of numerical results, were determined in a commercial finite element code. Several propagation and scattering problems in 2-D isotropic and anisotropic materials were solved and their results were compared with known analytical or experimental results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.92-98
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• 2001

When analyzing the scatting problem of multi-layered planar structures using closed-form Green's function, one of the main difficulties is that the numerical integrations for the evaluation of diagonal matrix elements converge slowly and are not so stable. Accordingly, even when the integration fur the singularity of type $e^{-jkr}/{\gamma}$, corresponding to the source dipole itself, is performed using such a method, this difficulty persists in the integration corresponding to the finite number of complex images. In order to resolve this difficulty, a new technique based upon the Gaussian quadrature in polar coordinates for the evaluation of the two-dimensional generalized exponential integral is presented. Stability of the algorithm and convergence is discussed. Performance is demonstrated for the example of a microstrip patch antenna.