• Title/Summary/Keyword: Discrete wave transforms

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Application of Wavelet Transform to Problems in Ocean Engineering

  • Kwon, Sun-Hong;Lee, Hee-Sung;Park, Jun-Soo
    • International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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    • v.6 no.1
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    • pp.1-6
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    • 2003
  • This study presents the results of series of studies, which are mainly devoted to the application of wavelet transforms to various problems in ocean engineering. Both continuous and discrete wavelet transforms were used. These studies attempted to solve detection of wave directionality, detection of wave profile, and decoupling of the rolling component from free roll decay tests. The results of these analysis, using wavelet transform, demonstrated that the wavelet transform can be a useful tool in analyzing many problems in the filed of ocean engineering.

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Application of Wavelet Transform to Problems in Ocean Engineering

  • KWON SUN-HONG;LEE HEE-SUNG;PARK JUN-SOO
    • Journal of Ocean Engineering and Technology
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    • v.17 no.3 s.52
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    • pp.1-6
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    • 2003
  • This study presents the results of series of studies, which are mainly devoted to the application of wavelet transforms to various problems in ocean engineering. Both continuous and discrete wavelet transforms were used. These studies attempted to solve detection of wave directionality, detection of wave profile, and decoupling of the rolling component from free roll decay tests. The results of these analysis, using wavelet transform, demonstrated that the wavelet transform can be a useful tool in analyzing many problems in the filed of ocean engineering.

Application of Directional Wavelet to Ocean Wave Image Analysis (방향 웨이브렛을 적용한 해양파 이미지 분석)

  • Kwon S. H.;Lee H. S.;Park J. S.;Ha M. K.
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.377-380
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    • 2002
  • This paper presents the results of a study investigating methods of interpretation of wave directionality based on wavelet transforms. Two-dimensional discrete wavelet was used for the analysis. The proposed scheme utilizes a single frame of ocean waves to detect their directionality. This fact is striking considering the fact that traditional methods require long time histories of ocean wave elevation measured at various locations. The developed schemes were applied to the data generated from numerical simulations and video images to test the efficiency of the proposed scheme in detecting the directionality of ocean waves.

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Protection Assessment using Reduced Power System Fault Data

  • Littler, T.B.
    • Journal of Electrical Engineering and Technology
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    • v.2 no.2
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    • pp.172-177
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    • 2007
  • Wavelet transforms provide basis functions for time-frequency analysis and have properties that are particularly useful for the compression of analogue point on wave transient and disturbance power system signals. This paper evaluates the compression properties of the discrete wavelet transform using actual power system data. The results presented in the paper indicate that reduction ratios up to 10:1 with acceptable distortion are achievable. The paper discusses the application of the reduction method for expedient fault analysis and protection assessment.

Development of compression method for fault data of digital protection relay using wavelet transforms (웨이블렛 변환을 이용한 디지털 보호계전기용 고장전류 데이터 압축기법 개발)

  • Choi, Ho-Woong;Kim, Yoon-Hoe;Kim, Byung-Jin;Kim, Bo-In;Kim, Jung-Han
    • Proceedings of the KIEE Conference
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    • 2005.07a
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    • pp.283-285
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    • 2005
  • Wavelet transforms provide basis functions for time-frequency analysis and have properties that are particularly useful for the compression of analogue point on wave transient and disturbance power system signals. This paper evaluates the compression properties of the discrete wavelet transform using actual power system data. The results presented in the paper indicate that reduction ratios up to 10:1 with acceptable distortion are achievable. This paper discussed the application of the reduction method for fault analysis and protection assessment.

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Image Registration and Fusion between Passive Millimeter Wave Images and Visual Images (수동형 멀리미터파 영상과 가시 영상과의 정합 및 융합에 관한 연구)

  • Lee, Hyoung;Lee, Dong-Su;Yeom, Seok-Won;Son, Jung-Young;Guschin, Vladmir P.;Kim, Shin-Hwan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.6C
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    • pp.349-354
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    • 2011
  • Passive millimeter wave imaging has the capability of detecting concealed objects under clothing. Also, passive millimeter imaging can obtain interpretable images under low visibility conditions like rain, fog, smoke, and dust. However, the image quality is often degraded due to low spatial resolution, low signal level, and low temperature resolution. This paper addresses image registration and fusion between passive millimeter images and visual images. The goal of this study is to combine and visualize two different types of information together: human subject's identity and concealed objects. The image registration process is composed of body boundary detection and an affine transform maximizing cross-correlation coefficients of two edge images. The image fusion process comprises three stages: discrete wavelet transform for image decomposition, a fusion rule for merging the coefficients, and the inverse transform for image synthesis. In the experiments, various types of metallic and non-metallic objects such as a knife, gel or liquid type beauty aids and a phone are detected by passive millimeter wave imaging. The registration and fusion process can visualize the meaningful information from two different types of sensors.