• Phonetics and Speech Sciences
• /
• v.5 no.4
• /
• pp.211-216
• /
• 2013

The IVA(Independent Vector Analysis) is a well-known FD-ICA method used to solve the frequency permutation problem. It generally works quite well for blind source separation problems, but still needs some improvements in the frequency bin permutation problem. This paper proposes a post-processing method which can improve the source separation performance with the IVA by fixing the remaining frequency permutation problem. The proposed method makes use of the correlation coefficient of power ratio between frequency bins for separated signals with the IVA-based 2-channel source separation. Experimental results verified that the proposed method could fix the remaining frequency permutation problem in the IVA and improve the speech quality of the separated signals.

• Polymer(Korea)
• /
• v.31 no.6
• /
• pp.505-511
• /
• 2007

Poly(lactide-co-glycolide)(PLGA) and hyaluronic acid (HA) has been widely used as biocompatible scaffold materials to regenerate tissue. In this present study, we fabricated microporous PLGA and HA loaded PLGA scaffolds by a emusion freeze-drying method. In order to confirm that the release profile of cytokine or water-soluble drugs, we manufactured the granulocyte macrophage colony stimulating factor(GM-CSF) loaded PLGA and HA-PLGA scaffold. All scaffolds were characterized using scanning electron microscope(SEM), mercury porosimeter and wettability measurement. Cell proliferation and viability were assessed by a 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) test. The porosity of HA-PLGA scaffold was greater than 95% with the total pore area of $261\;m^2/g$. The HA-FLGA scaffold exhibited well interconnected pores to allow greater cell adhesion and prolixferation. It was proven by higher cell viability in the HA-PLGA scaffold than PLGA alone. This may be due to the enhanced natural properties and higher water retention capacity of HA.

• Progress in Medical Physics
• /
• v.22 no.3
• /
• pp.140-147
• /
• 2011

The purpose of this study was to estimate internal motion using molecular sieve for quantitative improvement of lung tumor and to localize lung tumor in the small animal PET image by evaluated data. Internal motion has been demonstrated in small animal lung region by molecular sieve contained radioactive substance. Molecular sieve for internal lung motion target was contained approximately 37 kBq Cu-64. The small animal PET images were obtained from Siemens Inveon scanner using external trigger system (BioVet). SD-Rat PET images were obtained at 60 min post injection of FDG 37 MBq/0.2 mL via tail vein for 20 min. Each line of response in the list-mode data was converted to sinogram gated frames (2~16 bin) by trigger signal obtained from BioVet. The sinogram data was reconstructed using OSEM 2D with 4 iterations. PET images were evaluated with count, SNR, FWHM from ROI drawn in the target region for quantitative tumor analysis. The size of molecular sieve motion target was $1.59{\times}2.50mm$. The reference motion target FWHM of vertical and horizontal was 2.91 mm and 1.43 mm, respectively. The vertical FWHM of static, 4 bin and 8 bin was 3.90 mm, 3.74 mm, and 3.16 mm, respectively. The horizontal FWHM of static, 4 bin and 8 bin was 2.21 mm, 2.06 mm, and 1.60 mm, respectively. Count of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.10, 4.83, 5.59, 5.38, and 5.31, respectively. The SNR of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.18, 4.05, 4.22, 3.89, and 3.58, respectively. The FWHM were improved in accordance with gate number increase. The count and SNR were not proportionately improve with gate number, but shown the highest value in specific bin number. We measured the optimal gate number what minimize the SNR loss and gain improved count when imaging lung tumor in small animal. The internal motion estimation provide localized tumor image and will be a useful method for organ motion prediction modeling without external motion monitoring system.

• Polymer(Korea)
• /
• v.32 no.3
• /
• pp.193-198
• /
• 2008

Sibutramine is a highly crystalline and poorly water soluble drug as the appetite depressant for obesity treatment. In order to increase water solubility of sibutramine, microspheres including sibutramine were prepared by solid dispersion method using a spray dryer. The crystallinity and morphology of the prepared microspheres were confirmed by SEM and XRD. The morphology of micro spheres has gradually changed into spherical shape as increasing evaporation rate of solvent. According to XRD analysis, crystallinity of sibutramine in micro spheres was decreased by below 10%. Release behavior of microspheres was investiaged at pH 1.2, pH 6.8, and solubility of the sibutramine was significantly different depending on pH. The hard capsule showed fast release of sibutramine comparing with the tablet. These results demonstrated that the pharmaceutical preparation is able to control the release behaviors.

• Proceedings of the KIEE Conference
• /
• 2006.04b
• /
• pp.176-178
• /
• 2006

This paper is intended to research the speed response of switched reluctance motor (SRM) using sliding mode control method when load is changing. The simulation compare only control by PI controller with control by PI controller and sliding mode controller. It compare with speed response using MATLAB/SIMULINK.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.129.1-129
• /
• 2001

In this paper, we present an approach for matching images from finding interesting points and applying new image interpolation algorithm. New algorithms are developed that automatically align the input images match them and reconstruct 3-D surfaces. The interpolation algorithm is designed to cope with simple shapes. The proposed image interpolation algorithm generate a rotation image about vertical axes by an any angle from 4 base images. Each base image that was obtained from CCD camera has an angle difference of 90$^{\circ}$ The proposed image interpolation algorithm use the geometric analysis of image and depth information.

• Proceedings of the SAREK Conference
• /
• 2007.06a
• /
• pp.48-48
• /
• 2007

• Polymer(Korea)
• /
• v.31 no.3
• /
• pp.201-205
• /
• 2007

Biodegradable polymers such as polylactide, polyglycolide and poly (lactide- co-glycolide) (PLGA) have been extensively investigated because of easily controlled drug release rate, completely degradable materials without the toxic by-product, and good biocompatibility. But, according to the bulk erosion property of PLGA in vitro test, it had the disadvantage that first-order release reduced releasing amount slowly after excessive initial burst. In this study we used PLGA powder obtained through recrystallization to revise bulk erosion property of PLGA. The PLGA used in this study was prepared by vacuum drying method and to estimate release profiles of BCNU loaded PLGA wafer. We also evaluated the release profile of drug with the water soluble additive. It was found that the drug loaded PLGA recrystallized by vacuum drying method exhibited the initial burst and the constant rate of drug release compared to that prepared by a conventional method.

• The Monthly Technology and Standards
• /
• s.7
• /
• pp.92-102
• /
• 2002

• Proceedings of the Optical Society of Korea Conference
• /
• 2008.07a
• /
• pp.305-306
• /
• 2008