• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.6 s.121
• /
• pp.664-673
• /
• 2007

In this paper, the ID-FDTD scheme, proposed in Reference [1] and [2], is modified and completely analyzed. The modifications are composed of three parts: rigorous stability analysis, dispersion relation for linear lossy media, and new scaling factors for permittivity, permeability, and conductivity. As a result, it is shown that the proposed scheme has lower dispersion error in spite of larger time step than the conventional standard scheme of Reference [3]. To validate the scheme, there are presented two scattering examples, which show excellent results.

• Journal of Information Processing Systems
• /
• v.16 no.3
• /
• pp.718-732
• /
• 2020

Conducting sentiment analysis and opinion mining are challenging tasks in natural language processing. Many of the sentiment analysis and opinion mining applications focus on product reviews, social media reviews, forums and microblogs whose reviews are topic-similar and opinion-rich. In this paper, we try to analyze the sentiments of sentences from online webcast reviews that scroll across the screen, which we call live barrages. Contrary to social media comments or product reviews, the topics in live barrages are more fragmented, and there are plenty of invalid comments that we must remove in the preprocessing phase. To extract evaluative sentiment sentences, we proposed a novel approach that clusters the barrages from the same commenter to solve the problem of scattering the information for each barrage. The method developed in this paper contains two subtasks: in the data preprocessing phase, we cluster the sentences from the same commenter and remove unavailable sentences; and we use a semi-supervised machine learning approach, the naïve Bayes algorithm, to analyze the sentiment of the barrage. According to our experimental results, this method shows that it performs well in analyzing the sentiment of online webcast barrages.

• Journal of the Optical Society of Korea
• /
• v.7 no.4
• /
• pp.211-215
• /
• 2003

Statistical characteristics of the backscattered light from turbid tissues obtained by polarizationsensitive optical coherence tomography are investigated. The amplitude of the backscattered light is found to faithfully follow the Rayleigh distribution predicted by the scattering theory of electromagnetic waves in random media. The probability density function of the phase difference between the two orthogonal polarization components of the backscattered light is explicitly derived and then verified in comparison with the experimental data measured from in-vitro tissues of porcine ligament.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.2476-2481
• /
• 2007

An inverse radiation analysis is presented for the estimation of the wall emissivities for an absorbing, emitting, and scattering media with diffusely emitting and reflecting opaque boundaries. In this study, a repulsive particle swarm optimization(RPSO) algorithm which is a relatively recent heuristic search method is proposed as an effective method for improving the search efficiency for unknown parameters. To verify the performance of the proposed RPSO algorithm, it is compared with a basic particle swarm optimization(PSO) algorithm and a hybrid genetic algorithm(HGA) for the inverse radiation problem with estimating the wall emissivities in a two-dimensional irregular medium when the measured temperatures are given at only four data positions. A finite-volume method is applied to solve the radiative transfer equation of a direct problem to obtain measured temperatures.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.27 no.10
• /
• pp.1516-1523
• /
• 2003

An inverse radiation analysis is presented for the estimation of the boundary emissivities for an absorbing, emitting, and scattering media with diffusely emitting and reflecting opaque boundaries. The finite-volume method is employed to solve the radiative transfer equation for a two-dimensional irregular geometry. A hybrid genetic algorithm is proposed for improving the efficiency of the genetic algorithm and reducing the effects of genetic parameters on the performance of the genetic algorithm. After verifying the performance of the proposed hybrid genetic algorithm, it is applied to inverse radiation analysis in estimating the wall emissivities in a two-dimensional irregular medium when the measured temperatures are given at only four data positions. The effect of measurement errors on the estimation accuracy is examined.

• Proceedings of the IEEK Conference
• /
• 2004.06a
• /
• pp.143-146
• /
• 2004

Signals of the short wave part of centimetre, millimetre and optic wave length ranges are being broadly used in the communication, location and remote sensing systems with space channels. In this case the presence of discrete non-uniform mediums like orbital debris, space dust and other discrete formations in the propagation channel may have substantial influence upon the characteristics of wave processes. and thus upon the data system quality. Mathematical models for studying the discrete non-uniform mediums effect on the characteristics of electromagnetic wave propagation are analyzed in this paper.

• Nuclear Engineering and Technology
• /
• v.3 no.3
• /
• pp.121-128
• /
• 1971

A unified modal-nodal expansion of tile angular distribution of neutron flux in one spatial dimension is considered, following the proposal of Harms. Several standard nodal and/or modal methods of analysis are shown to be specializations of this technique. The modal-nodal moment from of the mono-energetic transport equation with isotropic sources and scattering is derived and the infinite medium eigenvalue problem solved. The technique is shown to yield results which approximate the exact value of the inverse diffusion length in non-multiplying media more accurately than standard methods of equal or somewhat greater computational complexity.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.10
• /
• pp.1887-1892
• /
• 2008

Novel poly(aspartic acid) derivatives conjugated with L-lysine moieties and their amphiphilic analogs were synthesized and characterized. The chemical structures of these polymers were confirmed using FT-IR and $^1HNMR$ spectroscopy. The physicochemical properties of amphiphilic copolymers were characterized using an electrophonetic light scattering spectrophotometer (ELS) and transmission electron microscopy (TEM). These results indicated a stable nanoparticle formation within aqueous media. These polymers have potential applications in the pharmaceutical and cosmetic fields as delivery vehicles for bioactive molecules.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.109.4-109
• /
• 2001

We have developed a laser ultrasonic system for visualization of elastic waves propagating on a solid surface, in order to visualize ultrasonic waves propagating on opaque media. This system can produce a series of successive images as an animation of wave propagation, because of scanning an optical heterodyne probe to measure surface transient displacements. Using this visualization technique, we observed the scattering and diffraction of ultrasonic waves around various shapes of artificial defects, and examined its application to nondestructive inspection. This imaging system provides various kinds of visualization images such as propagation image, amplitude image, arrival time image and velocity image. We have been confident that this technique is available for nondestructive inspection and materials ...

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.1639-1644
• /
• 2003

A hybrid genetic algorithm is developed for estimating the wall emissivities for an absorbing, emitting, and scattering media in a two-dimensional irregular geometry with diffusely emitting and reflecting opaque boundaries by minimizing an objective function, which is expressed by the sum of square errors between estimated and measured temperatures at only four data positions. The finite-volume method was employed to solve the radiative transfer equation for a two-dimensional irregular geometry. The results show that a developed hybrid genetic algorithms reduce the effect of genetic parameters on the performance of genetic algorithm and that the wall emissivities are estimated accurately without measurement errors.