• Journal of The Korean Society of Clinical Toxicology
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• v.3 no.1
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• pp.11-16
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• 2005

Chemical mixtures of components, each of which are present at less than guidance concentrations, may be hazardous due to additivity, interactions, or both. Toxicological interactions may increase the health hazard above what would be expected from an assessment of each component singly, or all components additively. So chemical mixture are a particular issue in public health. There are several approach to assess whether there are additivity or interaction in assessing toxicological effects, such as, components-based approach, physiologically-based pharmacokinetic /pharmacodynamic(PBPK/PD) models, hazard index method, and weight-of evidence method. If we consider interaction or additivity effects in assessing the health effects of chemcial mixtures, we can get more accurate information about toxicological effects and dose-response relationship in chemical mixtures.

• Journal of Korean Society for Quality Management
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• v.39 no.4
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• pp.500-506
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• 2011

Evolutionary operation (EVOP) proposed by Box(1957) is a method for continuous monitoring and improvement of a full-scale manufacturing process with the objective of moving the current operating conditions toward the better ones. EVOP in experiments with mixtures consists of screening vital few components and making small changes in the current operating condition by making small increments in the proportion of the screened component. In this paper, how to determine operating conditions in EVOP in experiments with mixtures around the current operating condition is proposed. The proposed methods are illustrated with the simulated data based on the well known flare experimental data described by McLean and Anderson(1966).

• 한국도로학회:학술대회논문집
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• 2010.09a
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• pp.99-107
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• 2010

A permanent deformation model was developed in this study based on the shear properties of asphalt mixtures such as cohesion and friction angle. Triaxial compressive strength (TCS) and repeated load permanent deformation (RLPD) tests on the three types of asphalt mixtures are performed at various loading and temperature conditions to correlate shear properties of asphalt mixtures to rutting performance. It is observed from the tests results that the ratio of shear stress to strength accurately identifies the mixture rutting performance. It could take care of not only mixture types but also load and temperature conditions dependences. Three different versions of the permanent deformation model based on different input levels are proposed and verified using the tests data. The proposed model based on the ratio of shear stress to strength can successfully predict the permanent deformation of various asphalt mixtures all the way up to the 10% of permanent strain including all three stages of permanent deformation in a wide range of loading and temperature conditions without changing model coefficients.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.4
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• pp.632-640
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• 2004

The purpose of this study is to clarify the influence of inert gas on the configuration characteristics of premixed turbulent propagating flames of hydrogen mixtures. Inert gas is changed to $N_2$, Ar, $CO_2$ and He keeping the laminar burning velocity of mixtures nearly the same value. A laser tomography technique was used to obtain the flame shape, and quantitative analyses were performed. The result shows that in the wrinkled laminar flame region, the surface area of turbulent flame is slightly dependent on the equivalence ratio and the kind of inert gas. It is also shown the region of convex part of flame toward the unburned gas is greater than that of toward the burned gas regardless of the kind of inert gas.

• Communications for Statistical Applications and Methods
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• v.18 no.6
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• pp.837-849
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• 2011

A self-organizing network is designed to estimate parameters of normal mixtures. SOMN achieves fast convergence and low possibility of divergence even when sample sizes are small, while PMLE eliminate unnecessary components. The proposed network effectively combines the good properties of SOMN and PMLE. Simulation verifies that the proposed network eliminates unnecessary components in normal mixtures when sample sizes are relatively small.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2383-2385
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• 1999

This paper describes the effect of particles on insulation characteristics of $SF_6-N_2$ mixtures such as breakdown voltages, lift-off voltages and maximum discharge. As a result, the breakdown voltage was increased with the increment of $SF_6$ and the mixture containing 20[%] of $SF_6$ has a breakdown voltage ratio factor better than the other mixtures. The lift-off voltage was nearly constant with all mixtures. Discharge was decreased with the increment of $SF_6$.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.301-306
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• 1999

Over 4.1 billion metric tons of non-hazardous solid wastes are generated in the United States anually. Therefore, there is a need to reuse or reprocess as many products or by -products as possible. In this report, the aggregates produced from Naval Shipyard and Charlexton area dredge spoils are designated as NC and DS, respectively. The major objective of this portion was to determine the feasibility of the use of these aggregates in concrete mixtures. According to test results, the unit weight of concrete mixtures containing NC and DS (vitrified glass) was lower than the control mixture, and the control mixture produced higher compressive and bending strength compared to mixtures containing vitrified glass. However the mixtures containing vitrified glass still could be used in the field based on the minimum criteria set for the mix desgin.

• Speech Sciences
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• v.12 no.4
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• pp.31-42
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• 2005

Recently, Gaussian Mixture Model (GMM), a special form of CHMM, has been applied to speaker identification and it has proved that performance of GMM is better than CHMM. Therefore, in this paper the speaker models based on GMM and a new GMM using the modified EM algorithm are introduced and evaluated for text-independent speaker identification. Various experiments were performed to evaluate identification performance of two algorithms. As a result of the experiments, the GMM speaker model attained 94.6% identification accuracy using 40 seconds of training data and 32 mixtures and 97.8% accuracy using 80 seconds of training data and 64 mixtures. On the other hand, the new GMM speaker model achieved 95.0% identification accuracy using 40 seconds of training data and 32 mixtures and 98.2% accuracy using 80 seconds of training data and 64 mixtures. It shows that the new GMM speaker identification performance is better than the GMM speaker identification performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.279-283
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• 1998

The electron swarm parameters in the$CF_4$(O.l%, 5%)+Ar mixtures are measured by time of flight method over the E/N(Td) range from 10 to 300LTdl. A two-term approximation of the Boltzmann equation analysis and Monte Carlo simulation have been also used to study electron transport coefficients. We have calculated W, NDL, NDT, $\alpha$ and the limiting breakdown electric field to gas mixtures ratio in pure $CF_4$ gas and$CF_4+Ar$ mixtures. The measured results and the calculated results have been compared each other paper.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1999-2001
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• 2000

Impulse breakdown voltage characteristics of sulphur-hexafluoride/nitrogen ($SF_{6}-N_{2}$) mixtures were presented. The applied voltages were the positive and negative lightning impulse (1.2/44${\mu}s$) and oscillating impulse ($0.4{\mu}s$/2.08MHz) voltages. The predischarge current was observed to clarify the breakdown mechanism. The electrode system was consisted of plane to plane configuration with a needle-shaped protrusion whose length and diameter are 10mm and 1mm. The measurements were carried out at the gas pressure of mixtures up to 0.5MPa with nitrogen concentrations varying from 5 to 20%. The electrical breakdown in $SF_{6}-N_{2}$ mixtures develops with steplike pulses in leader mechanism. The minimum breakdown voltages for the negative lightning and oscillating impulse voltages were higher than those for the positive.