Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 4 of 4

Full-Text Articles in Physical Sciences and Mathematics

Singular Value Decomposition In Image Noise Filtering And Reconstruction, Tsegaselassie Workalemahu Apr 2008

Singular Value Decomposition In Image Noise Filtering And Reconstruction, Tsegaselassie Workalemahu

Mathematics Theses

The Singular Value Decomposition (SVD) has many applications in image processing. The SVD can be used to restore a corrupted image by separating significant information from the noise in the image data set. This thesis outlines broad applications that address current problems in digital image processing. In conjunction with SVD filtering, image compression using the SVD is discussed, including the process of reconstructing or estimating a rank reduced matrix representing the compressed image. Numerical plots and error measurement calculations are used to compare results of the two SVD image restoration techniques, as well as SVD image compression. The filtering methods …


On The Use Of Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins Jan 2008

On The Use Of Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins

Faculty of Informatics - Papers (Archive)

Space-Time-Frequency Codes (STFCs), which haverecently been proposed in the literature for Multiband OFDMUltra-Wideband (MB-OFDM UWB) systems to improve thesystem capacity, error performance and wireless communicationrange, are all constructed based on orthogonal structures. Thispaper examines the application of Quasi-Orthogonal STFCs(QOSTFCs) to enhance further either data rate or error performancein the recently proposed STFC MB-OFDM UWB systems.It will be shown that QOSTFCs can provide significantly bettererror performance, compared to the conventional MB-OFDMUWB (without STFCs) as well as to the Orthogonal STFCs(OSTFCs) of the same order, at the same data rate, withoutincreasing the total transmission power. Equivalently, QOSTFCscan provide higher data rates with …


Cooperative Communication In Space-Time-Frequency Coded Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins, Tadeusz A. Wysocki Jan 2008

Cooperative Communication In Space-Time-Frequency Coded Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins, Tadeusz A. Wysocki

Faculty of Informatics - Papers (Archive)

Though cooperative communication has been intensively examined for general wireless systems, such as mobile and ad-hoc networks, it has been almost unexplored in the case of Space-Time-Frequency Coded Multi-band OFDM Ultra-Wideband (STFC MB-OFDM UWB). This paper proposes a framework of cooperative communication in such systems where nodes are equipped with only one antenna. Simulation results show that cooperative communication might, in some cases, provide better error performance than non-cooperative communication without any additional transmission power.


Application Of Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Alfred Mertins, Le Chung Tran Jan 2008

Application Of Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Alfred Mertins, Le Chung Tran

Faculty of Informatics - Papers (Archive)

This paper examines the application of Quasi-Orthogonal Space-Time-Frequency Codes (QOSTFCs) to advance either data rate or error performance in recently proposed Space-Time-Frequency Coded Multiband OFDM Ultra-Wideband (STFC MB-OFDM UWB) communications systems. It is shown that QOSTFCs can provide significantly better error performance, compared to the conventional MB-OFDM UWB (without STFCs) and to the Orthogonal STFCs (OSTFCs) of the same order, at the same data rate, without increasing the total transmission power. In other words, QOSTFCs can provide higher data rates with the same error performance, compared to OSTFCs.