• Bulletin of the Korean Chemical Society
• /
• v.26 no.11
• /
• pp.1706-1710
• /
• 2005

The excited-state intramolecular proton transfer (ESIPT) fluorescence in the 2-(2'-hydroxyphenyl)benzoxazole (HBO) derivatives with different electron donor and acceptor substituents was studied by spectroscopic and theoretical methods. Changes in the electronic transition, energy levels, and orbital diagrams of HBO analogues were investigated by the semi-empirical molecular orbital calculation and were correlated with the experimental spectral position of ESIPT keto emission. It was found that the presence of substituents, regardless of their nature, resulted in the red-shifted absorption relative to HBO. However, the spectral change of the ESIPT fluorescence was differently affected by the nature of substituent: hypsochromic shift with electron donor and bathochromic shift with electron acceptor.

• ETRI Journal
• /
• v.36 no.3
• /
• pp.514-517
• /
• 2014

In this paper, alternative dynamic features for speech recognition are proposed. The goal of this work is to improve speech recognition accuracy by deriving the representation of distinctive dynamic characteristics from a speech spectrum. This work was inspired by two temporal dynamics of a speech signal. One is the highly non-stationary nature of speech, and the other is the inter-frame change of a speech spectrum. We adopt the use of a sub-frame spectrum analyzer to capture very rapid spectral changes within a speech analysis frame. In addition, we attempt to measure spectral fluctuations of a more complex manner as opposed to traditional dynamic features such as delta or double-delta. To evaluate the proposed features, speech recognition tests over smartphone environments were conducted. The experimental results show that the feature streams simply combined with the proposed features are effective for an improvement in the recognition accuracy of a hidden Markov model-based speech recognizer.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
• /
• 2001.06a
• /
• pp.1282-1282
• /
• 2001

Near Infrared (NIR) spectra has long been used in industry to monitor rates of reactions via calculation of analyte concentrations. However, the kinetic information is inherent in the data through spectral ratios. Two-dimensional correlation spectroscopy (2D-COS) is a spectral method that is based on changes (e.g. concentration) in time and is therefore uniquely suited for reaction monitoring. This method is especially useful in the understanding of how the reaction(s) proceeds. We will show the application of 2D-COS to synthetic kinetic data from different reaction orders to illustrate the method. We will then show application to real reactions of various orders. Finally, we will illustrate how 2D-COS will be of specific interest to developing optimized industrial reactions.

• Proceedings of the KOSOMBE Conference
• /
• v.1994 no.05
• /
• pp.72-74
• /
• 1994

This paper describes the effect of autonomic nervous activity on Heart rate variability and peripheral blood pressure with power spectral analysis and its characteristics of chaotic attractors. The aim of this paper is to access the applicability of spectral and dimension analysis of heart rate variability and peripheral blood pressure, attributed to changes in autonomic nervous system activity. About 60 mininutes of Heart rates and synchronized peripheral blood pressure were recorded on 10 healthy man while various mental and physical conditions. The results shows the availability to evaluate the autonomic nervous activities.

• Journal of the Optical Society of Korea
• /
• v.18 no.6
• /
• pp.788-792
• /
• 2014

It has been a critical issue to reduce the size of spectrometers in many fields such as on-chip chemical and biological sensing. The proposed plasmonic channel-waveguide with a sub-micrometer width has a cutoff frequency which enables us to control wavelength dependent propagation properties. We focused on the capability of the waveguide for spectral-to-spatial mapping when the waveguide width changes gradually. In this paper, we propose a plasmonic tapered channel-waveguide structure as a compact spectrometer with a physical size of $0.24{\times}2.0{\times}0.20{\mu}m^3$. The scattering point just above the tapered waveguide moves linearly depending on the wavelength of the injecting light. The spectral-to-spatial mapping can be improved by increasing the tapered length.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2003.10a
• /
• pp.623-626
• /
• 2003

Image analysis was performed with two color systems, Red-Green-Blue (RGB) values and normalized Hue-Saturation-Intensity (HSI). We conducted field studies in Cheongju to determine canopy spectral reflectance and digital image analysis of rice. Spectral reflectance measurements made with a portable spectrometer(LI-1800) correlated with growing stage and digital images for rice. Images in which the color was specified by the common RGB coordinates could be used when there was a sharp contrast between the color of the rice and that of the field soil. In the absence of sharp contrast, identification of the rice covered area was much easer after the color had been transformed into HSI coordinates. This study introduced fundamental theories in digital image analysis and applied that for field situations rice.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.17 no.8
• /
• pp.747-756
• /
• 2007

The hydropneumatic suspension units, which have applied to the tracked vehicles, have the spring and damping function in the unit. The nonlinear characteristics such as roadwheel rotation effects, gas behavior changes, hydraulic damping characteristics, hysterisis, and frictional forces have been ignored or simplified to analyze the mathematical models in many areas. This study describes the dynamic characteristics and the nonlinear behaviors of hydropneumatic suspension unit considering the nonlinear effects such as the nonlinear spring and nonlinear damping through the simulation and the experiment. The utility of nonlinear analysis through the higher-order spectral analysis is also presented.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.7
• /
• pp.2332-2338
• /
• 2011

In this study, we proposed a new promising idea of utilizing moving window principal component analysis (MWPCA) as a sensitive diagnostic tool to detect the presence of peak position shift. In this approach, the moving window is constructed from a small data segment along the wavenumber axis. For each window bound by a narrow wavenumber region, separate PCA analysis was applied. Simulated spectra with complex spectral feature variations were analyzed to explore the possibility of MWPCA technique. This MWPCA-based detection of the peak shift, potentially coupled with 2D correlation analysis to provide additional verification, may offer an attractive solution.

• Journal of Aerospace System Engineering
• /
• v.10 no.1
• /
• pp.1-7
• /
• 2016

During flight of the aircraft, the vortex merging phenomenon appears under the certain condition between co-rotating vortices which were generated at the wing tip and lifting-surface. And then these merged vortices at both sides show counter-rotating pattern to affect on the downstream of the aircraft. In this paper, the numerical simulations are conducted assuming this phenomenon in two-dimensional co-rotating or counter-rotating vortices pairs. Two-dimensional incompressible Navier-Stokes equations were converted into Vorticity-Streamfunction form and the Galerkin spectral method was adopted. The third order Runge-Kutta method was used for time integration. The effects on the vortex merger and degree of vortex merger were investigated according to time, Reynolds number, and changes in the distance between two vortices.

• The Bulletin of The Korean Astronomical Society
• /
• v.35 no.1
• /
• pp.66.2-66.2
• /
• 2010

We have studied the properties of interstellar turbulence as observed by Boston University-Five College Radio Astronomy Observatory (BU-FCRAO) Galactic Ring Survey (GRS). This observation uses 13CO J=$1{\rightarrow}0$ emission with high spectral resolution of 0.21 kms-1 and covers wide galactic plane regions ($18^{\circ}$ < 1 < $55.7^{\circ}$ and -1 < b < $1^{\circ}$). Firstly, we measured the one dimensional power spectrum of 13CO intensity along the galactic longitude and along the galactic latitude. We found the slope of the power spectrum changes around the molecular ring structure and the center of the galactic plane. Secondly, we explored how the power spectral slope is related with the velocity dispersion of supersonic giant molecular clouds in the GRS. Finally, we suggest the turbulent nature of the interstellar medium is connected with star formation activities in spiral arms.