• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.149-153
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• 1999

As VLSI technology advances rapidly, the operating frequency of digital systems becomes very fast. In such a high-speed system, there are many factors that threaten signal integrity. The noise sources in digital system include the noises in power supply, ground bounce and packaging media and distortions on single and multiple transmission lines. This paper will present a technology survey useful in the design of Gigabit interconnection systems. Some case studies have been constructed which show the lossy transmission line effect of skin effect. dielectric loss, with backplane connectors using the theoretical and practical conditions.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.438-443
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• 1998

A simple single-stage AC/DC forward converter with transformer magnetic energy feedback technique for power factor correction is proposed. The operational principle of the proposed converter is presented. The proposed converter gives the good power factor correction, low line current harmonic distortions, and tight output voltage regulation. The prototype shows high power factor with low line current harmonics.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.269-275
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• 1999

This paper presents the results of thermoelastic wear phenomena in ventilated disk brakes for a high-speed train using finite element method. The computed results show that the sinusoidal distortions due to non-uniform distributions of temperature profiles may lead to thermoelastic wears at the rubbing surface. This may decrease the life of a disk brake and produce micro-cracks, noise and squeals between two rubbing surfaces.

• Tribology and Lubricants
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• v.15 no.4
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• pp.291-296
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• 1999

This paper presents the results of thermoelastic wear behaviors in ventilated disk brakes for a high-speed automotive and train using the finite element method. The computed results show that the sinusoidal distortions due to non-uniform distributions of temperature profiles may lead to thermoelastic wears on the rubbing surface. This may decrease the service life of a disk brake and produce micro-cracks, noise and squeals between two rubbing surfaces.

• Bulletin of the Korean Space Science Society
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• 1995.10a
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• pp.15-15
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• 1995

No Abstract, See Full Text

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.243-246
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• 2002

The proliferation of digitized media(audio, image and video) is creating a processing need for copyright enforcement schemes that protect copyright ownership. we argue that a watermark must be placed in perceptually significant components of a signal if it is to be robust to signal distortions and malicious attack. In this paper, RGB coordinate image is transformed into LUV coordinate, it include the characteristics of, Human vision and then the UV component is transformed into NxN block DCT transform. we propose a technique for embedding the watermark of visually recognizable mark into the middle frequency domain of image.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.7
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• pp.434-441
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• 2003

This paper proposes a new quantitative and objective image quality metric which is essential to verify the performance of block-based DCT image coding. The proposed metric considers not only global distortion of coded image such as spatial frequency sensitivity and channel masking using HVS based multi-channel model, but also structural distortions caused block-based coding. The experimental results show a strong correlation between proposed metric and subjective metric.

• Journal of applied mathematics & informatics
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• v.11 no.1_2
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• pp.327-340
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• 2003

For motion analysis electromagnetic sensors are often used to measure positions and orientations of human subjects. It is observed from several experiments of the Ergonomics Research group that there exist systematic errors and unexpected serious distortions due to some metal masses in the test area. A calibration process is necessary to fix these errors. In this article three models are proposed to correct position measurement errors based on observations from calibration experiments.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.239-240
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• 2007

We suggest an image watermarking algorithm. We perform the modified Log-Polar Mapping (LPM) and the DFT/DCT on the original image and embed the watermark. Binary images are used for watermarks. Watermarking strength is adaptively adjusted depend on the mapped data Experimental results show that this method is robust to JPEG and rotation distortions.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2285-2289
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• 2020

Protactinium contamination is a mayor issue in the thorium fuel cycle. We investigate, in this work, the consequences of Pa incorporation in vacancy defects and interstitials in Th, ThC and ThN. We calculate charge transfers and lattice distortions due to these incorporations as well as migration paths and energies involved in the diffusion of Pa.