• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.506-509
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• 2008

Mathematical models have been developed to calculate hydrodynamic characteristics of perforated-wall structures. Most of the models separate the fluid regions into front and back of the wall, assume the solution in each region, and calculate the solution by using the matching condition at the wall. The matching condition involves the permeability parameter, which can be calculated by the methods proposed by Mei et al. or Sollitt and Cross. In this study, we compare these two methods. The former is advantageous because all the related variables are known, but it gives wrong result in the limit of long waves, i.e. zero transmission and perfect reflection of very long waves. In deep water, the latter predicts smaller transmission and larger reflection than the former, and vice versa in shallow water. In the latter method, the friction coefficient decreases as the wall thickness or the porosity of the wall increases.

• Korean Journal of Remote Sensing
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• v.38 no.3
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• pp.283-298
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• 2022

As Synthetic Aperture Radar (SAR) image can be acquired regardless of the weather and day or night, it is highly recommended to be used for Automatic Target Recognition (ATR) in the fields of surveillance, reconnaissance, and national security. However, there are some limitations in terms of cost and operation to build various and vast amounts of target images for the SAR-ATR system. Recently, interest in the development of an ATR system based on simulated SAR images using a target model is increasing. Attributed Scattering Center (ASC) matching and template matching mainly used in SAR-ATR are applied to target classification. The method based on ASC matching was developed by World View Vector (WVV) feature reconstruction and Weighted Bipartite Graph Matching (WBGM). The template matching was carried out by calculating the correlation coefficient between two simulated images reconstructed with adjacent points to each other. For the performance analysis of the two proposed methods, the Synthetic and Measured Paired Labeled Experiment (SAMPLE) dataset was used, which has been recently published by the U.S. Defense Advanced Research Projects Agency (DARPA). We conducted experiments under standard operating conditions, partial target occlusion, and random occlusion. The performance of the ASC matching is generally superior to that of the template matching. Under the standard operating condition, the average recognition rate of the ASC matching is 85.1%, and the rate of the template matching is 74.4%. Also, the ASC matching has less performance variation across 10 targets. The ASC matching performed about 10% higher than the template matching according to the amount of target partial occlusion, and even with 60% random occlusion, the recognition rate was 73.4%.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.627-630
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• 2005

Novel unified criterion to optimize power coupling at optical directional couplers with discontinuous input/output interfaces is first defined and evaluated numerically. The numerical results reveal that maximum power transfer between guiding slabs without discontinuous interfaces is dominated by conventional phase-matching condition while the guiding structures with discontinuous interfaces has maximum power transfer at an equi-partition condition, which describes the power distribution condition between two rigorous modes propagating through optical couplers.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.383-386
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• 1995

A universal dispersion equation for magnetostatic waves(MSW) propagating in the film with arbitrary-multiple magnetic layers magnetized in an arbitrary direction was derived with a matching boundary condition method. The computing result curves of delay time were shown.

• Korean Journal of Optics and Photonics
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• v.8 no.5
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• pp.377-381
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• 1997

Poling condition in 2 mol% MgO-doped $LiNbO_3$ crystals is investigated by varying the amplitude of poling electric field from 3V/cm to 7V/cm. It is found that 5V/cm is the best value for the formation of single domain by analysing the characteristics of the second harmonic generation(SHG) as the function of temperature. The temperature dependence of the phase-matching profile of SHG for the crystal applied by a spatially modulated electric field is observed to be very different from the simple sinc function. The distorted profile can be consistently fitted with the numerical simulations. This shows that the crystal homogeneity can be tested by the SHG temperature phase-matching profile. In addition, the thermo birefringence coefficient and electro birefringence coefficient of SHG were measured from the temperature dependence of phase-matching profile and shifts of phase-matching temperature by appling electric field along c-axis.

• Journal of the Korean Magnetics Society
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• v.22 no.6
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• pp.210-215
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• 2012

The absorption performance of a metal-backed single layered electromagnetic wave absorber is optimized at matching conditions of thickness and frequency indicating the maximum returns loss of incidence electromagnetic wave in the contour map. These matching conditions are obtained by applying the electromagnetic impedance to the transmission line theory, which depend on the complex permeability and complex permittivity of absorber material. The magnetic materials with high permeability can enhance the matching thickness condition to the wide frequency range based on the decrease of permeability with frequency and it can be used as a wideband electromagnetic wave absorber material. Therefore, the magnetic materials with higher saturation magnetization and lower permittivity than NiZn ferrite can be applied to the wideband electromagnetic wave absorber in order to satisfy the newly enforcing the electromagnetic compatibility regulation in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.327-332
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• 2008

New RF matcher module has been proposed in this paper for improvement of RF matcher in plasma etcher system using in semiconductor and display panel manufacturing process. New designed warm gear was used instead of bevel gear in new driving module, and control system was re-arranged with one-chip micro-process technique. The matching performance of new match module was improved in various process condition with reduction of backlash and matching time, and flexible motion of motor compared commercial match module. However this new type RF match module will improve the productivity in etching process of the mass production line.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1620-1627
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• 2017

In this paper, we design an observer-based $H_{\infty}$ fuzzy controller for interval type-2 Takagi-Sugeno (T-S) fuzzy systems under imperfect premise matching. The designed observer-based controller can effectively estimate the state of the system and make fuzzy system satisfy the $H_{\infty}$ disturbance attenuation performance. Using the slack matrix, the derived stabilization condition is expressed in terms of a linear matrix inequality. Finally, the effectiveness of the proposed method is verified through a simulation example.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.2
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• pp.95-101
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• 2001

Most robust control schemes for stabilizing the systems with uncertainties require that the systems are satisfied with matching conditions. This paper is proposed to robust control using the time delay estimation for the nonlinear single input systems not satisfying the matching conditions. Synthetic input concept is used to design the control law. The unmatched uncertainties considered in this paper are more general than other studies and they need not a special form or information about their bound. We applied the proposed method to a single pendulum with a motor system.

• Journal of the Korean Data and Information Science Society
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• v.27 no.4
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• pp.1091-1100
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• 2016

This paper considers the noninformative priors for the linear function of parameters in the lognormal distribution. The lognormal distribution is applied in the various areas, such as occupational health research, environmental science, monetary units, etc. The linear function of parameters in the lognormal distribution includes the expectation, median and mode of the lognormal distribution. Thus we derive the probability matching priors and the reference priors for the linear function of parameters. Then we reveal that the derived reference priors do not satisfy a first order matching criterion. Under the general priors including the derived noninformative priors, we check the proper condition of the posterior distribution. Some numerical study under the developed priors is performed and real examples are illustrated.