Thesis (Ph.D.)--University of South Australia, 1996.

Studies have discovered higher frequencies of single nucleotide polymorphisms (SNPs) in different mitochondrial genes are associated with subnormozoospermia. However, the frequencies of SNPs in ND1 and ND2 are not unknown. The present research was aimed to determine the frequencies of SNPs in ND1 and ND2 genes of the mitochondrial genome in fertile and subfertile men and whether changes in codon usage was associated with fertility phenotypes. Total genomic DNA from 157 semen samples was extracted using the proteinase K/SDS digestion procedure, followed by phenol/chloroform purification and ethanol precipitation. ND1 and ND2 genes were amplified respectively from 80 and 92 DNA samples from different fertility groups. Each PCR product was sequenced to identify mutations. Codon change resulting from a nucleotide substitution was determined by comparison with a reference mtDNA sequence obtained from the NCBI database. The frequency of codon usage in the reference mtDNA was determined by the computer program MEGA version 2.1. Eleven synonymous nucleotide substitutions and two non-synonymous substitutions were found in this study. Four SNPs were previously characterized; all SNPs were homoplasmic. None of the SNPs were likely to affect the function of the proteins on the basis of the hydrophobicity plots or secondary structure predictions. Sixty two percent of synonymous mutations were found to change from a high to a low relative codon usage values; 37% of synonymous mutations changed from a low to a high relative usage value. Chi-square (χ²) test (χ²= 0.067 with 1 d.f.) showed that there was no significant difference at the 5% level between these changes. Thus, change in codon usage was not related to semen quality in men. Further, there were no statistically significant differences in the observed frequencies of SNPs of fertile and subfertile men. However, the sample size was small and this study was only focused on a single NZ Caucasian population. Further study including larger and more diverse population samples may provide further insight into the functional importance of codon usage and its relevance to fertility

The introduction of cellular wireless systems in the 1980s has resulted in a huge demand for personal communication services. This demand has made larger capacity systems necessary. This has been partially satisfied by the introduction of second generation digital systems. New third generation systems are now under going standardisation and will require even more efficient utilisation of the spectrum if the high bandwidth features and larger capacity are to become a reality. Motivated by these growing requirements we discuss methods of achieving large improvements in spectral efficiency and performance. Multiple-user communications over a channel can only be achieved with some form of diversity. In this work we point out that the efficient utilisation of the dimensions of space, time, and frequency will ultimately maximise the system capacity of a multiple-user system. We apply our receiver techniques solely to the base-station design where capacity limitations are currently present. We note however, that some of these techniques could also be applied at the mobile terminal receiver. We primarily focus our attention on the direct-sequence code-division multiple-access (DS/CDMA) channel, since this channel is inherently interference limited by other users in the cell of interest. We exploit a new powerful channel coding technique named " turbo coding" for its iterative decoding approach. We show how we can substitute the inner convolutional code of a turbo code encoder with the CDMA channel. By " iterative detection/decoding" or " turbo equalisation" at the receiver we achieve performance results which show the interference from other users to approach complete removal. We develop and analyse a new, low complexity, iterative interference canceller/decoder. This receiver has complexity per user linear with the memory of the channel and independent of the number of users in the system. We extend this receiver to more realistic channels that are asynchronous and include multi-path, and include spatial diversity by using an antenna array at the receiver. The CDMA channel we study exclusively uses randomly generated spreading codes. With this channel model we still achieve single user performance (no interference from other users) with a 10logL gain from L antenna elements and a gain of up to 10logP from P multi-path components. With any new receiver design, sensitivity to channel parameter errors is of paramount interest. We find that the sensitivity of our receiver is low with respect to the parameter errors induced. This is as we desire for a realisable receiver design. Finally we investigate the application of this new iterative interference canceller/decoder receiver to a number of other interference channels. These include the intersymbol interference (ISI) channel, partial response signalling (PRS), and continuous phase modulation (CPM). For these channels excellent performance improvement is generally achieved by the utilisation of the iterative interference canceller/decoder solution. / Thesis (PhD)--University of South Australia, 1999

Thesis (Ph. D.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 84-89).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 87-91). Also available via the Internet.

Thesis (Ph.D.)--University of Delaware, 2008. / Principal faculty advisors: Lori L. Pollock and Lisa Marvel, Dept. of Computer & Information Sciences. Includes bibliographical references.

Zugl.: Innsbruck, University, Diss., 2006.

Project (M.Eng.) - Simon Fraser University, 2004. / Theses (School of Engineering Science) / Simon Fraser University.

Thesis (Ph.D.)--University of Texas at Arlington, 2009.

Thesis (Ph. D.)--Drexel University, 2004. / Includes abstract and vita. Includes bibliographical references (leaves 113-130).