• ETRI Journal
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• v.35 no.5
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• pp.827-837
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• 2013

In this paper, we present wideband common-mode (CM) noise suppression using a vertical stepped impedance electromagnetic bandgap (VSI-EBG) structure for high-speed differential signals in multilayer printed circuit boards. This technique is an original design that enables us to apply the VSI-EBG structure to differential signals without sacrificing the differential characteristics. In addition, the analytical dispersion equations for the bandgap prediction of the CM propagation in the VSIEBG structure are extracted, and the closed-form expressions for the bandgap cutoff frequencies are derived. Based on the dispersion equations, the effects of the impedance ratio, the EBG patch length, and via inductances on the bandgap of the VSI-EBG structure for differential signals are thoroughly examined. The proposed dispersion equations are verified through agreement with the full-wave simulation results. It is experimentally demonstrated that the proposed VSI-EBG structure for differential signaling suppresses the CM noise in the wideband frequency range without degrading the differential characteristics.

• Korean Journal of Veterinary Research
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• v.43 no.2
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• pp.231-237
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• 2003

Listeria (L.) monocytogenes in samples could not be detected occasioally by faster growth of other Listeria spp. especially L. innocua. The aim of this study was to develop the differential media and multiplex polymerase chain reaction (PCR) assays for the rapid detection of L. monocytogenes. L. monocytogenes colonies were characterized by their ${\beta}$-hemolysis with fluorescence under 366 nm UV light on the Listeria hemolysis agar (LHA). L. innocua, a species commonly present in foods, did not produce ${\beta}$-hemolysis on LHA. Therefore, one or more colonies of L. monocytogenes were easily distinguished from large populations of L. innocua. The multiplex PCR assays were developed to distinguish from L. monocytogenes and other Listeria spp. with two pairs of primers. The primers were designed in 16S rRNA and listeriolysin O gene for specific amplification of all members of the genus Listeria and L. monocytogenes, respectively. The multiplex PCR assays produced 560 and 938 bp products in L. monocytogenes; only 938 bp products in the genus Listeria. The multiplex PCR assays could detect as little as 50 pg of L monocytogenes DNA. These results indicated that the differential media and multiplex PCR assays might be useful diagnostic tools for the rapid detection of L. monocytogenes.

• Structural Engineering and Mechanics
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• v.22 no.3
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• pp.279-292
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• 2006

A new approach using the differential quadrature method (DQM) is derived for analysis of non-uniform beams resting on nonlinear media in this study. The influence of velocity dependent viscous damping and strain rate dependent viscous damping is investigated. The results solved using the DQM have excellent agreement with the results solved using the FEM. Numerical results indicated that the DQM is valid and efficient for non-uniform beams resting on non-linear media.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.10
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• pp.4108-4125
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• 2015

This paper presents a scalable coding method for depth images by considering the quality of synthesized images in virtual views. First, we design a new edge detection algorithm that is based on calculating the depth difference between two neighboring pixels within the depth map. By choosing different thresholds, this algorithm generates a scalable bit stream that puts larger depth differences in front, followed by smaller depth differences. A scalable scheme is also designed for coding depth pixels through a layered sampling structure. At the receiver side, the full-resolution depth image is reconstructed from the received bits by solving a partial-differential-equation (PDE). Experimental results show that the proposed method improves the rate-distortion performance of synthesized images at virtual views and achieves better visual quality.

• Journal of KIISE:Software and Applications
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• v.37 no.6
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• pp.417-429
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• 2010

Reversible watermarking inserts watermark into digital media in such a way that visual transparency is preserved and then enables to restore the original media from the marked one without any loss of media quality. This watermarking can be applied to quality-sensitive imaging such as medical imaging, military imaging, remote-sensing imaging, and precious artwork, where the original media should be preserved during image processing and analysis. In this paper, a reversible image watermarking technique that embeds message bits by modifying the differential histogram of adjacent pixels is presented. In order to satisfy both high embedding capacity and visual quality, the proposed technique exploits the fact that adjacent pixels in the image have highly spatial correlation. Also, we prevent overflow/underflow problem and salt-and-pepper artifacts by employing a predicted error compensation scheme. Through experiments using various test images, we prove that the presented technique provides perfect reversibility and high embedding capacity, while maintaining the induced-distortion low.

• Korean journal of aerospace and environmental medicine
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• v.29 no.3
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• pp.93-95
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• 2019

Middle-ear barotrauma is a common problem reported by aircrew members and passengers. Studies have shown that 20~50% of passengers report ear complaints during the flight or after landing. Barotitis media is defined as an acute or chronic inflammation caused by a pressure differential between the tympanic cavity and the surrounding atmosphere. The Problems caused by otitis media or sinusitis of aircrew during landing and take-off can be a threat to aviation safety. Therefore, the aviation medical examiner should know about barotitis media of aircrews. In this paper, we aimed to learn what is barotitis media and how much it could affect aircrews. Also, we aimed to evaluate how barotitis media could make an impact on crews during flight, and how to manage these problems.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.5 no.4
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• pp.243-248
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• 1993

In this research, unsteady groundwater flow in unconfined and homogeneous three layer aquifers is studied theoretically and experimentally. Numerical solutions are obtained by Runge Kutta and Runge Kutta Gill method after transforming the governing nonlinear partial differential equations to nonlinear ordinary differential equations. Experimental apparatus includes a test section filled with fine, medium and coarse sands. Experimental results are compared with the numerical solutions and both experimental and numerical results correspond well with each other. This numerical approach may be also applied to the cases which have more aquifers.

• Structural Engineering and Mechanics
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• v.29 no.6
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• pp.673-687
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• 2008

In this paper, a thermo-viscoelastic problem in an infinite isotropic medium in two dimensions in the presence of a point heat source is considered. The fundamental equations of the problems of generalized thermoelasticity including heat sources in a thermo-viscoelastic media have been derived in the form of a vector matrix differential equation in the Laplace-Fourier transform domain for a two dimensional problem. These equations have been solved by the eigenvalue approach. The results have been compared to those available in the existing literature. The graphs have been drawn for different cases.

• Journal of the Korea Society of Computer and Information
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• v.20 no.7
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• pp.17-24
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• 2015

In this paper, we propose a method to solve ghosting problem. To generate adaptive background, using an exponentially decreasing number of frames, may improve object detection performance. To extract moving objects from the background by using a differential image, detection error may be caused by object rotations or environmental changes. A ghosting problem can be issue-driven when there are outdoor environmental changes and moving objects. We studied that a differential image by adaptive background may reduce the ghosting problem. In experimental results, we test that our method can solve the ghosting problem.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.5
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• pp.621-626
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• 1985

Unsteady groundwater flow in a three-layer unconfined aquifer has been studied theoretically and experimentally. Two different methods have been used in solving the governing equations of the flow, the nonlinear partial differential equations; (1) The governing equations are linearized for each layer and approximate solutions are obtained. (2) The governing equations are transformed to nonlinear ordinary differential equations, which are solved numerically by Runge-Kutta procedure. Fine, middle sized and coarse sands are used in the experiments. It is found that the solutions from the method(2) ( the reduction of partial differential equations to ordinary differential equations) give better agreement with the experimental results than the solution from the method(1).