• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.112-113
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• 2004

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.521-526
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• 2012

It is essential for the accurate time-domain prediction of broadband noise due to turbulence-cascade interaction to develop inflow/outflow boundary conditions to satisfy the following three requirements: to maintain the back ground mean flow, to nonreflect the outgoing disturbances and to generate the specified input gust. The preceding study(1) showed that Perfectly Matched Layer (PML) boundary condition was successfully applied to absorb the outgoing disturbances and to generate the specified gust in the time-domain computations of broadband noise due to interaction of incident gust with a cascade of flat-plates. In present study, PML boundary condition is extended in order to predict steady mean flow that is needed for the computation of noise due to interaction of incident gust with a cascade of airfoils. PML boundary condition is originally designed to absorb flow disturbances superimposed on the steady meanflow in the buffer zone. However, the steady meanflow must be computed before PML boundary condition is applied on the flow computation. In the present paper, PML equations are extended by introducing source term to maintain desired mean flow conditions. The extended boundary condition is applied to the benchmark problem where the meanflow around a cascade of airfoils is predicted. These illustrative computations reveal that the extended PML equations can effectively provide and maintain the target meanflow.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.7
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• pp.685-691
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• 2012

It is essential for the accurate time-domain prediction of broadband noise due to turbulence-cascade interaction to develop inflow/outflow boundary conditions to satisfy the following three requirements: to maintain the back ground mean flow, to nonreflect the outgoing disturbances and to generate the specified input gust. The preceding study showed that perfectly matched layer(PML) boundary condition was successfully applied to absorb the outgoing disturbances and to generate the specified gust in the time-domain computations of broadband noise due to interaction of incident gust with a cascade of flat-plates. In present study, PML boundary condition is extended in order to predict steady mean flow that is needed for the computation of noise due to interaction of incident gust with a cascade of airfoils. PML boundary condition is originally designed to absorb flow disturbances superimposed on the steady meanflow in the buffer zone. However, the steady meanflow must be computed before PML boundary condition is applied on the flow computation. In the present paper, PML equations are extended by introducing source term to maintain desired mean flow conditions. The extended boundary condition is applied to the benchmark problem where the meanflow around a cascade of airfoils is predicted. These illustrative computations reveal that the extended PML equations can effectively provide and maintain the target meanflow.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.763-766
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• 2005

Ubiquitous Computing owes Internet and development of computer network and appeared. RFID (Radio frequency Identification) technology is noted by point technology to realize this. However, PML that present in Auto-lD Center is defined point part to describe information of object, and necessary part is to use defining extension separately in actuality application. So that can define object type that can be used for electron tag data processing in RFID application service because do fetters to Auto-lD Center's PML Core in this treatise hereupon and apply in physical distribution circulation service field, designed object information data model.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.4
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• pp.405-410
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• 2007

This study was to investigate the hypolipidemic effect of powdered mulberry leaves (PML) and water extract of powdered mulberry leaves (WML) on high-fat fed mice. Male C57BL/6 mice were divided into four groups; a normal group (N), a high-fat (HF) group, a high-fat group supplemented with PML (HF-PML) and a high-fat group supplemented with WML (HF-WML). The PML or WML was added to a standard diet based on 1% dried mulberry loaves (1g PML/100g diet and 0.22g WML/100g diet) for 6 weeks. Body weight and organ weights were not different among thle groups in high-fat fed mice, whereas food intake and daily energy intake were significantly (p<0.05) lowered in the HF-PML group. In plasma and liver, the supplementation of PML and WML significantly (p<0.05) lowered cholesterol and triglyceride concentrations compared to the HF group. The HDL-cholesterol/total cholesterol ratio was significantly (p<0.05) higher in the HF-PML and HF-WML groups than in the B:.w group. The fecal triglyceride and cholesterol concentrations were significantly (p<0.05) increased in the HF-PML and HF-WML groups compared to the HF group. Hepatic lipid regulating enzyme activities, fatty acid synthase, fatty acid ${\beta}-oxidation$ and carnitine palmitoyl transferase were significantly lower in the HF group than in the N group. However, the activities of these hepatic lipid regulating enzymes activities were significantly (p<0.05) elevated in the HF-PML and HF-WML groups compared to the HF group. Accordingly, these results suggest that PML and WML improve plasma and hepatic lipid levels partly by increasing fecal lipid excretion and enhancing hepatic lipid regulating enzymes activities.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.2
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• pp.87-95
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• 2018

This paper introduces a new explicit spectral element method for the simulation of SH-waves in semi-infinite domains. To simulate the wave motion in unbounded domains, it is necessary to reduce the infinite extent to a finite computational domain of interest. To prevent the wave reflection from the trunctated boundaries, perfectly matched layer(PML) wave-absorbing boundary is introduced. The forward problem for simulating SH-waves in PML-truncated domains can be formulated as second-order PDEs. The second-order semi-discrete form of the governing PDEs is constructed by using a mixed spectral elements with Legendre-gauss-Lobatto quadrature method, which results in a diagonalized mass matrix. Then the second-order semi-discrete form is transformed to a first-order, whose solutions are calculated by the fourth-order Runge-Kutta method. Numerical examples showed that solutions of SH-wave in the two-dimensional analysis domain resulted in stable and accurate, and reflections from truncated boundaries could be reduced by using PML boundaries. Elastic wave propagation analysis using explicit time integration method may be apt for solving larger domain problems such as three-dimensional elastic wave problem more efficiently.

• Journal of Korean Neurosurgical Society
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• v.29 no.12
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• pp.1682-1687
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• 2000

Progressive multifocal leukoencephalopathy(PML) is a fatal demyelinating disease that occurs in immunocompromised hosts. We report a case of PML that developed in patient with T cell lymphoma of head and neck. During chemotherapy for lymphoma, she was confused and had memory impairment. A magnetic resonance imaging of the brain revealed confluent signal change at white matter of the frontal lobe, insula, and anterior limb and genu of internal capsule. The lesion was confirmed with brain biopsy and the histopathological finding was compatible with PML.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.846-856
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• 1998

In this paper, we have applied Berenger's perfectly matched layer(PML) absorbing boundary conditition(ABC) with three dimension at the propagation direction of field, side boundary and upper boundary in which evanescent and radiation field is exist. Even though the same computationaal domain is used, PML is superior to other ABC in the absorbing ability that is obtained reflective coefficient about $10^{-4}$ unit for the propagation wave, but PML is ineffective in absorbing evanescent field. Also we have compared dispersive characteristics of the microstrip with Kobayashi's emprical method, and obtaind very similar result, but 0.8% error is generated at the dc or near.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.57-62
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• 2008

Finite difference method using not general SSG(standard staggered grid) but RSG(rotated staggered grid) was applied to simulation of elastic wave propagation. Special free surface boundary condition such as imaging method is needed in finite difference method using SSG in elastic wave propagation but free surface boundary condition in finite difference method using RSG is easily solved with adding air layer. Recently PML(Perfectly Matched layer) is widely used to eliminate artificial reflection waves from finite boundary because of its' greate efficiency. Absorbing ability of CPML(convolutional Perfectly Matched Layer) that is more efficient than that of PML was applied to FDM using RSG in this study. The results of CPML eliminated artificial boundary waves very effectively in FDM using RSG in being compared with that of Cerjan's absorbing method.

• Structural Engineering and Mechanics
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• v.51 no.4
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• pp.685-705
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• 2014

This paper presents a new formulation for forward scalar wave simulations in semi-infinite media. Perfectly-Matched-Layers (PMLs) are used as a wave absorbing boundary layer to surround a finite computational domain truncated from the semi-infinite domain. In this work, a hybrid formulation was developed for the simulation of scalar wave motion in two-dimensional PML-truncated domains. In this formulation, displacements and stresses are considered as unknowns in the PML domain, while only displacements are considered to be unknowns in the interior domain. This formulation reduces computational cost compared to fully-mixed formulations. To obtain governing wave equations in the PML region, complex coordinate stretching transformation was introduced to equilibrium, constitutive, and compatibility equations in the frequency domain. Then, equations were converted back to the time-domain using the inverse Fourier transform. The resulting equations are mixed (contain both displacements and stresses), and are coupled with the displacement-only equation in the regular domain. The Newmark method was used for the time integration of the semi-discrete equations.