No description available.

No description available.

No description available.

Speech collected through a microphone placed in front of the mouth has been the primary source of data collection for speech recognition. There are only a few speech recognition studies using speech collected from the human ear canal. In this study, a speech recognition system is presented, specifically an isolated word recognizer which uses speech collected from the external auditory canals of the subjects via an in-ear microphone. Currently, the vocabulary is limited to seven words that can be used as control commands for a wide variety of applications. The speech segmentation task is achieved by using the short-time signal energy parameter and the short-time energy-entropy feature (EEF), and by incorporating some heuristic assumptions. Multi-layer feedforward neural networks with two-layer and three-layer network configurations are selected for the word recognition task and use real cepstrum (RC) and mel-frequency cepstral coefficients (MFCCs) extracted from each segmented utterance as characteristic features for the word recognizer. Results show that the neural network configurations investigated are viable choices for this specific recognition task as the average recognition rates obtained with the MFCCs as input features for the two-layer and three-layer networks are 94.731% and 94.61% respectively on the data investigated. Average recognition rates obtained using the RCs as features on the same network configurations are 86.252% and 86.7% respectively.

No description available.

by P.J. Wormald. / Thesis (M.D.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (p. 195-217). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Fusarium Ear Blight is a devastating fungal disease of cereals and due to the contamination of the harvested grain with a range of trichothecene mycotoxins presents a risk to human and animal health. The re-emergence of Fusarium graminearum on wheat and maize, the evolution of more aggressive fungal strains and the lack of an effective control strategy, has increased the need for a greater understanding of the disease aetiology. This project aimed to enhance the understanding of the interaction between F. graminearum and wheat (Triticum aestivum), through the utilisation of microscopy and molecular pathogenomics. A detailed investigation of the infection process revealed a prolonged latent period of intercellular infection that preceded host cell death, intracellular colonisation and the onset of disease symptoms. Phenotypic differences in colonisation and mycotoxin gene expression implied that hyphae within the two phases of infection were transcriptionally distinct, while a bioinformatic analysis described the fungal secretome. The two fungal gene-deficient strains assessed, top1 and tri5, were unable to establish symptomless infection or spread throughout the wheat ear, in the presence or absence of mycotoxin production, suggesting the existence of additional virulence factors. Subsequently, a genome wide transcriptome investigation of the two phases of infection, using both Affymetrix and RNA-sequencing technologies, revealed the unique expression profile, and secretome, of the advancing hyphal front of the symptomless infections. This greater understanding of the biphasic interaction will provide a benchmark for comparison with the single gene deficient strains. Finally, a laser capture microdissection procedure was developed to enable future cell-type specific transcriptome experiments. Collectively, I have discovered and developed a model of how F. graminearum establishes symptomless and symptomatic infection. In doing so, this study has enhanced the understanding of this non-biotrophic pathosystem, providing many new lines of investigation, which could greatly improve crop protection strategies.

Thesis (M.S.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 169-186).

published_or_final_version / Biochemistry / Doctoral / Doctor of Philosophy

Sox2, a HMG box transcription factor, is well known for its role in stem cell maintenance, iPS (induced pluripotent stem cell) induction, and development of neural tissues such as central nervous system and sensory organs. Sox2 has been demonstrated to be essential for the development of inner ear sensory patches. It has been shown that Sox2 is under the regulation of multiple regulatory elements to obtain a tissue specific manner. Two allelic mouse mutants, yellow submarine (Ysb) and Light coat and circling (Lcc) show hearing and balance impairments with different severity. They were made by random insertions of a transgene (pAA2) and X-ray irradiation respectively. Ysb and Lcc are both localized to chromosome 3 and involve complex chromosomal rearrangements. The Sox2 coding region is intact in the mutants, while the Sox2 expression in the otocyst is greatly reduced in Ysb and totally lost in Lcc, which indicates the tissue specific reduction of Sox2 may be due to the rearrangement of Sox2 regulatory element(s). Since Sox2 null mutants die before implantation, the two Sox2 inner ear mutants are valuable models for studying Sox2 knock down (Ysb) and Sox2 knock out (Lcc) condition in the inner ear. To understand the molecular basis behind Sox2 regulation in the inner ear, this project aims to identify the Sox2 otic regulatory elements, and potential Sox2 downstream targets involved in the development of inner ear. Previous work has indicated that Nop1 and Nop2 are the otic specific regulatory elements of Sox2 in chicken ear. In this project, transgenic mice were generated using Nop1-Nop2, and the result showed Nop1-Nop2 could drive Sox2 expression to the dorsal side of the otiv vesicle, which is different from the endogenous Sox2 expression pattern. Therefore, Nop1 and Nop2 may require other regulatory element(s) to gain a correct regulatory pattern. BAC(RP23-335P23), which contained the DNA sequences close to Ysb integration site 1 was also been tested in transgenic mice. Interestingly, the result showed that BAC(RP23-335P23) could drive Sox2 expression to the ventral side of the otic vesicle, indicating that this BAC may contain the Sox2 otic regulatory element(s). In this project, the binding relationship between Sox2 protein and Math1 enhancer has also been identified using chromatin immunoprecipitation (Ch-IP). Results showed that Sox2 could bind to Math1 enhancer A in the inner ear cochlea. So Sox2 may regulate Math1 through binding to Math1 enhancer A in inner ear development. Using a bioinformatics approach, potential Sox2 target genes in inner ear development have been identified from public microarray data on E9 to E15 inner ear tissue by the presence of conserved Sox2 binding sites. Among these potential targets, 4 genes (Itga6, Erbb3, Sox10 and Mycn) have been selected based on their known functions. Their expression patterns in the cochlea of wild type, Ysb and Lcc were verified. The identification of Sox2 downstream target genes using a bioinformatics approach will help us to understand the molecular basis of Sox2 regulation, and also understand the role of Sox2 in the inner ear development. / published_or_final_version / Biochemistry / Master / Master of Philosophy