• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.177-182
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• 1995

Since one property(i.e. coarseness, orientation, regularity, granularity etc.) of ultrasound liver images was not sufficiently enough to classify the characteristics of livers, we used the multi-feature vectors from ultrasound images to diagnose the liver disease. The proposed classifier, which uses the multi-feature vectors and Bayes decision rule, performed well for the classification of normal, fat and cirrhosis liver. In our simulation, we used the Battacharyya distance and Hotelling Trace Criterion to select the best multi-feature vectors for the classifier and obtained less classification errors than other methods using single feature vector.

• Korean Journal of Mathematics
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• v.6 no.1
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• pp.67-70
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• 1998

Let ${\eta}(\tau)=q^{1/24}\prod_{n=1}^{\infty}(1-q^n)$, where $q=e^{2{\pi}i{\tau}}$ and ${\tau}{\in}\mathbb{C}$. Then the transformation $$g(\tau)={\rho}\frac{\{\eta(\frac{\tau+1}{2})\eta(\frac{\tau+2}{2})\}^{16}}{\eta(\tau)^{24}}({\bar{{\rho}}{\eta}}(\frac{\tau+1}{2})^8+{\eta}(\frac{\tau+2}{2})^8)^2$$ is holomorphic for Im ${\tau}$ > 0, and has the property $$g(\tau+1)=g(\tau),\;g(-\frac{1}{\tau})={\tau}^{12}g(\tau)$$. (Theorem)

• Bulletin of the Korean Mathematical Society
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• v.46 no.4
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• pp.645-656
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• 2009

J. Wang [21] proposed a problem: whether the Hyers-Ulam-Rassias stability of Jensen's equation for the case p, q, r, s $\in$ ($\beta$, $\frac{1}{\beta}$) \ {1} holds or not under the assumption that G and E are $\beta$-homogeneous Fspace (0 < $\beta\;\leq$ 1). The main purpose of this paper is to give an answer to Wang's problem. Furthermore, we proved that the stability property of Jensen's equation is not true as long as p or q is equal to $\beta$, $\frac{1}{\beta}$, or $\frac{\beta_2}{\beta_1}$ (0 < $\beta_1,\beta_2\leq$ 1).

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.11-18
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• 1999

For the proper design of a slender compression member, the exact determination of the elastic critical load is crucial, In the cases of non-prismatic compression members, the determinations of the elastic critical load cannot be usually expressed in closed forms. h this paper, the non-symmetrically tapered compression members with arbitrary boundary conditions me analysed by using the finite element method to determine the elastic critical load. The main parameters considered in the numerical analysis are the In Parameter, $\alpha$ and the sectional property parameter, m. To generaliza the unmerical analysis, of the computed results for each sectional parameter, m are presented in algebraic equations, which agrees fairy well with those by F.E.M in most cases.

• Progress in Superconductivity and Cryogenics
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• v.2 no.1
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• pp.31-34
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• 2000

this paper deals with the initial magnetic field decay for a large scale superconducting magnet e.g. NMR/MRI magnet. The high resolution image can not be obained during the periods of the initial field decay. It is known that all superconducting materials have the property of diamagnetism. This diamagnetism is usually explained with the concept of screening current. We assumed that the existence of the screening currebt. we assumed that the existence of the screening current makes the current distribution in the superconducting wire non-uniform. And the initial magnetic field decay is caused steady current state in the view of its pattern. The initial magnetic field decay is caused by the change of the current distribution between the energizing state and persistent current mode. in this paper the theoretical analysis for the current distributions has been introduced for each state. The experiments have been carried out to verify transport currents in order to veperiments, it small at the higher transport current.

• Proceedings of the KIEE Conference
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• 2000.07e
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• pp.22-25
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• 2000

Time dependent ozone generation characteristics of some oxide layers grown by ozone on the surface of corona discharge wires have been investigated experimentally in air ambience. Four wires of stainless steel, iron, silver and copper were used for the corona discharge wire of an ozone generator. And the effect of the metal oxide layers on ozone generation was studied and the contamination morphology of each layers was characterized. With the SEM images and the EDS spectra, it was found that all the surface of the corona wire were oxidized by the generated ozone and contaminated by airborne particles through the gradient force. As a result, the morphology and the electrical property of metal oxide layer grown on corona wire surface influenced on ozone generation characteristics i.e. discharge mechanisms.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1522-1524
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• 1998

Experimental results on the effect of $SiO_2$ addition to Bi based ZnO varistor show that secondary phases in microstructure and nonlinear coefficient are increased, and that leakage current is decreased with $SiO_2$ additive content. The varistor with 0.1 mol%-$SiO_2$ additive exhibits lower resistive current than other specimen at ($E_{1mA}$ x 0.6) applied voltage and temperature of $115^{\circ}C$ for 350h.

• Textile Coloration and Finishing
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• v.11 no.2
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• pp.46-54
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• 1999

The conventional dyeing of wool/cotton blends involves a two bath two step method, i.e., after dyeing of the wool component with acid dyes in an acidic dyebath at $100^\circ{C}$, the dyeing of the cotton component with reactive dyes in an alkaline dyebath is performed. In order to overcome the disadvantage of the conventional two bath two step dyeing method of wool/cotton blends, it had prompted significant effort to the development of the one bath dyeing method which can accomplish savings in time, energy and water usage. To improve dyeing property of wool/cotton blends, cotton component was pretreated with cationizing agent containing chlorohydrine group in aqueous solution of sodium hydroxide. This study was carried out to investigate dyeing possibilities of wool/cationized cotton blends with acid dye/reactive dye by one bath two step method.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.766-771
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• 2000

This study is mainly concerned with friction and wear properties for the piston ring of non-lubricating air compressor which made of PTFE-polyimide composites. At the PTFE and polyimide alone mixture specimens, PTFE80%-polyimide20%, which shows the lowest men friction coefficient and specific wear rate at 0.94m/s sliding speed. At each of carbon, copper and oxide lopper mixed with PTFE80%-polyimide20%. In case of copper10%, at 0.94m/s sliding speed, the mean friction coefficient shows 0.087, which is the lowest value in all specimens. In case of the specific wear rate, copper30% specimen shows the lowest value of $2.537E-5(mm^3/Nm)$ in all specimens.

• Journal of Biomedical Engineering Research
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• v.11 no.1
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• pp.131-140
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• 1990

To improve antithrombogenicity of polymer that used in vascular graft and artificial organs, seeding of human endothelial cells on the polyurethane was studied. Human endothelial cells were ismlated from human umbilical veins, using type I collagenase, and identified with goat anti vWF antibodies. Human endothilial cell seeding was tried upon the polyurethane which has good mechanical property and resists stresses. The hydrophobic polyurethane surface was changed hydrophilic by corona discharf:e treatment. Surface hydrophilicity was measured with Wilhemly plate method and the goniometer. To evaluate matrix protein adsorption, fibronectin adsorption test was done. To eveluate cell adhesion, human endothelial cell attachment forces were measured rising a perfusion chamber of , ism diamter. Less cells were detached from the hydrophilically treated polyurethane. This showed that corona discharge on the polyurethane could improve matrix adsorption and endothelial cell attachment.