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Novel antenna selection and dimensionality reduction in massive MIMO communication with the exploitation of multiple antenna radio channels
No full textEmpirical thesis.Bibliography: pages 117-136.Chapter 1. Introduction -- Chapter 2. Background and related work -- Chapter 3. Antenna selection in massive MIMO communication -- Chapter 4. Spatial structure of multiple antenna radio channels -- Chapter 5. Dimensionality reduction of large matrices -- Chapter 6. Conclusions and future work -- References.Massive multiple-input-multiple-output (MIMO) has the potential to offer a high system capacity in the fifth generation of wireless communication systems, exploiting the large number of degrees of freedom gained by utilising many transmit antennas at the base station. For a signal to be transmitted from an antenna element at the base station, the element needs to be connected to a radio-frequency chain which comprises Digital to-Analogue converters, a power amplifier and mixers etc. The total number of radio frequency chains equals the number of antenna elements used for active transmission. Therefore, the radio-frequency switching matrix represents the hardware components required in antenna selection for interconnection of the radio-frequency chains with their selected antennas.However, having a large number of antennas there are numerous challenges, in terms of hardware system complexity, large matrix sizes and signal correlation due to less space between antennas. To confront these problems, novel antenna-selection algorithms and dimensionality-reduction algorithms are proposed and spatial-correlation based channel models are explored.Antenna selection algorithms based on central Principal Component Analysis (PCA) are developed, and antenna selection algorithms using noncentral Principal Component Analysis (NPCA) and Linear Dependence Avoidance System (LDAS) are proposed. These algorithms reduce the correlation between the signals received by users. The performance of the proposed schemes with different antenna-selection algorithms and sum-capacity is evaluated.Signal correlation between the antennas is modelled by using spatially correlated channel models such as the Kronecker Model and the Weichselberger Model. The correlation matrices at both ends of the link are approximated by using Power Azimuth Spectrum (PAS) models. These models give the analytical signal modelling in correlative environments used to test the proposed antenna-selection algorithms to study the system behaviour in different realistic environments.Finally, the analysis of PCA is used that can reduce the size of huge matrices significantly, which saves a large number of computations as compared with the full-dimensional system. This thesis analyses the dimensionality reduction of large matrices using Floating Point Operation (FLOP) methods.This method is also implemented in the above-mentioned spatially correlated channel models to evaluate the throughput.The results in this thesis are presented mainly in four parts: a) novel antenna-selection algorithms, b) application of novel antenna selection algorithms to spatially correlated channels, c) large matrix computations are reduced using dimensionality reduction techniques, d) analysis of matrix dimension reduction for spatially correlated channel models. This dissertation therefore presents the methodologies of lowering hardware complexity, reducing large matrices’ dimensions and modelling signal correlation by using spatially correlated channel models that affect the design in the fifth generation of MIMO broadcast wireless communication systems.Mode of access: World wide web1 online resource (xxxi, 136 pages) diagrams, graph
Improving the clinical applicability of electrophysiological assessments and cochlear imaging in adult cochlear implant patients
No full textEmpirical thesis."Audiology Section, Department of Linguistics, Faculty of Human Sciences, Macquarie University, Sydney, Australia" -- title page.Bibliography: pages 113-141.Chapter 1. Introduction -- Chapter 2. Cost and reported benefits of electrophysiology testing during cochlear implant surgery -- Chapter 3. Developing a method for assessing the integrity of electrically-evoked auditory brainstem response (eABR) measures -- Chapter 4. A clinically feasible technique of assessing scalar location of cochlear implant basal electrodes using Cone Beam Computed Tomography -- Chapter 5. Assessing cochlear length using Cone Beam Computed Tomography in adults with cochlear implants -- Chapter 6. General discussion, results and conclusion -- References -- Appendix.Cochlear implants (CI) are recognized as the most successful neural prosthesis to date. With the technology and surgical techniques for implantation continually improving, the potential for improved speech perception abilities in individuals with severe-to-profound hearing loss, also increases. While different factors which influence these outcomes have been identified, no consensus exists regarding the degree to which each factor contributes (see Holden et al., (2013)). A major challenge of using speech perception scores to evaluate cochlear implantation outcomes is that understanding degraded (such as vocoded speech from a cochlear implant) speech uses both linguistic and cognitive resources (working memory and attention). Therefore, it is not a sensitive outcome measure for assessing minor technological or surgical modifications for the implant. On the other hand, electrophysiological measures of auditory function, such as electrically evoked auditory brainstem responses (eABRs) could provide a more sensitive measure of the effects of electrode positioning, surgical outcomes, or cochlear neural integrity. However, a robust understanding of how these measures could be used to inform functional outcomes of implantation has not yet been reached.The research reported in this thesis is based on an online questionnaire data from clinical audiologists working at the Sydney Cochlear Implant Centre (SCIC) in NSW and retrospective datasets collected from the centre, which has a long history of measuring objective responses intra-operatively during cochlear implantation surgery. This thesis firstly explores the current clinical use of these objective measures by the clinical audiologists, then investigates the potential clinical utility of imaging and intraoperative electrophysiological measures in CI to increase test battery efficiency and applicability. Further, this thesis describes a clinically viable tool of measuring cochlear length using Cone beam Computed Tomography (CBCT) with the implant array in situ, providing a more accurate method of measuring cochlear lengths and thereby provides insights into a variable which influences final electrode placement.results of these investigations demonstrate that considerably greater clinical use of the intra-operative measures could be made to increase the efficiency of cochlear implant programming (or mapping) during the switch-on appointment. In particular, the results showed that electrically-evoked auditory brainstem response (eABR) measures are a sensitive tool for predicting CI mapping parameters particularly at cochlear implant “switch-on”, although this is negatively affected by poor scalar placement. As such, this thesis demonstrates that CBCT can be used to identify scalar placement within the basal turn of the cochlea, thereby providing greater accuracy of predicting mapping outcomes. Finally, this thesis demonstrates the considerable inter-individual cochlear anatomical variation which highlights the need for a more individualized approach to CI for more consistent electrode placement.Mode of access: World wide web1 online resource (xiii, 149 pages) illustration
Productivity growth, efficiency, and export orientation - evidence from Vietnamese small and medium enterprises
No full textTheoretical thesis.Bibliography: pages 61-76Chapter 1 - Introduction -- Chapter 2 - Theoretical background and literature review -- Chapter 3 - Methodology -- Chapter 4 - Results and discussion -- Chapter 5 - ConclusionThis study uses the DEA-based Malmquist index to measure and examine the firm level total factor productivity and its components (i.e., technical efficacy, scale efficacy, and technological change) of small and medium enterprises in two Vietnamese manufacturing industries (wood and manufacturing, and rubber and plastic) for the period from 2005 to 2013. It then applies an endogenous switching regression model to analyses the effects of export participation on the productivity and efficiency of a firm, explicitly controlling for the effect of self-selection into foreign markets. The findings confirm the superiority in technical efficiency of exporters over non-exporters, especially in the rubber and plant industry. In addition, exporters use more labor-intensive technology to align with Vietnam's competitive advantage. Moreover, productivity is found to be driven by pure efficiency change rather than other sources. Lastly, previous export status is the key factor that affects the decision to export.Mode of access: World wide web1 online resource (ix, 76 pages
Middle-class Pacific Islanders in Australia: negotiating identity, race and class
No full textTheoretical thesis.Bibliography: pages 49-54.Chapter 1: Introduction -- Chapter 2: Reviewing the literature -- Chapter 3: Integration -- Chapter 4: Racism -- Chapter 5: Inbetweeness -- Chapter 6: Conclusion.By examining in-depth interviews with ten middle-class Pacific Islanders, this thesis explores the complexities they experience in negotiating identity and belonging through the intersections of inclusion, exclusion and inbetweeness. Inclusion is experienced through formal and informal modes of 'integration' which have facilitated the respondents sense of belonging; exclusion meanwhile relates to the everyday racism faced by respondents that act as a constant reminder they do not fully belong; and lastly a sense of inbetweeness must be negotiated as they occupy being privileged socio-economically whilst simultaneously stigmatized due to racial ethnic markers. This thesis reveals the complexity of the middle-class migrant identity which continues to be little examined in the literature on immigrant settlement in Australia. Moreover, it expands research on the settlement experience of Pacific Islanders in Australia by focusing on its middle class as well as unpacking the heterogeneity of this pan-ethnic grouping.1 online resource ( iii, 54 pages
French language learning in junior secondary school: student perception, classroom interaction and implications for retention
No full textTheoretical thesis.Bibliography: pages 286-305.1. Introduction -- 2. Literature review -- 3. Methodology -- 4. Results -- 5. Discussion -- 6. Conclusion -- Appendices.This research was undertaken due to the researcher’s concern with improving retention in elective foreign language learning in the Australian secondary school context. Although more than 300 languages are spoken in Australian homes (Australian Bureau of Statistics, 2017), when it comes to learning languages at school, it has been observed that the level of student participation in elective stages of language study is low. In the state of New South Wales, the prevalent ‘mono-lingual mindset’ (Clyne, 2005) has led to a situation where, once the mandatory 100-hour study period of a foreign language is exhausted in junior secondary school (Years 7 & 8), more than two thirds of the student population never study a language again. This qualitative research project, conducted in one case study school in Sydney, explored Year 7 & 8 language learners’ perceptions of the process of language study and their reasons for opting in or out of elective courses. It collected classroom data through non-participant observation, surveys and class interviews. Data analysis with a Conversation Analytic approach has revealed that learners’ perceptions have a major impact on their ongoing involvement with the subject. The double nature of fun that the teacher and students talk into being in classroom interaction is unveiled to be a key element in the formation of learner perception. The findings of the study have lead to the construction of a model that explains how learner perception of language learning as fun is formed in the teacher talk dominated classroom environment and what criteria need to be met to sustain this perception as a catalyst for continued language learning. The study sheds new light on the formation of learner perception, provides new directions for teacher professional learning, and addresses factors that influence retention in elective stages of language study.1 online resource (360 pages
Novel UV direct write fabrication technique for surface electronic structures on diamond
No full textEmpirical thesis.Bibliography: pages 43-46.1. Introduction -- 2. Background -- 3. UV etching : a novel tool for surface processing -- 4. Instrumentation, experimental and measurements methods -- 5. Results and discussion -- 6. Conclusions and future works -- Appendix -- References.This thesis examines the feasibility of using a novel UV etching process to enhance fabrication of electronic devices on hydrogen-terminated diamond surfaces. Diamond is considered as a potential material for high performance electronic applications due to its unique and extreme mechanical and electronic properties. A p-type conductivity originating from a hydrogen terminated diamond surface forms the basis for a variety of electronic devices. In this thesis, the highly-controlled surface modification provided by UV etching has been used to simplify fabrication process of some electronic devices. Resistors, a Schottky diode, and a MOSFET have been fabricated using the technique, and their electrical properties are presented. The potential for the technique to enhance diamond surface MOSFETs performance is discussed.Mode of access: World wide web1 online resource (xvi, 46 pages) illustrations (some colour
Determinants of demand for cultural experience goods: an application to the market for books
No full textEmpirical thesis.Bibliography: pages 189-210.1. Introduction -- 2. Consumer choice in economic thought -- 3. The economic analysis of cultural goods -- 4. A general model of demand for cultural experience goods -- 5. Empirical application : the market for books -- 6. Research methodology -- 7. Results and hypothesis testing -- 8. Conclusions and ideas for further research -- References -- Appendices.This thesis aims to contribute towards the economic literature on the consumer choice of cultural goods. A theoretical model of demand that distinguishes `cultural experience goods' from other `experience goods' is developed. Treating the cultural nature of a good as distinct from other factors known to influenceconsumer choice (such as a good's experiential nature, the role of taste development and the impact of technological change) permits the examination of how its presence not only influences demand in general but also how this influence varies across different consumer groups.This thesis makes two distinct empirical contributions, both of which relate to the chosen category of cultural experience goods, books. Firstly, in order to provide empirical support to the widely accepted theoretical proposition that cultural goods have the potential to embody both a cultural and economic value, a unique survey of readers is conducted. Assessments of a variety of cultural value components along with measurements of willingness to pay for books written by a selection of renowned authors were collected from survey respondents. Econometric analysis of these valuations revealed that readers are able to put a price on a book's ability to stir the imagination. However, a number of other cultural value dimensions that were highly valued by readers remained resistant to monetary evaluation.The second empirical contribution of this thesis relates to the development of a stated preference discrete choice experiment in order to test the predictions of the theoretical model of demand. A total of 242 Australian readers each completed 12 choice tasks resulting in the collection of 2904 choice observations. Respondents were also asked a series of additional questions regarding their socio-demographic characteristics and book reading habits. Binary logit, multinomial logit and latent class models were estimated from the survey data. Results for the hypotheses relating to the cultural nature of a good provide evidence to suggest consumers are willing to pay a `premium' for goods of a cultural nature. However, this willingness to pay varies considerably across different consumer groups. A variety of other hypotheses relating to a good's experiential nature, the role of taste development in cultural good consumption and the impact of new consumption formats are also examined in detail.The conclusion of this thesis emphasises the importance of accounting for the cultural nature of a good in models of demand and suggests how the results can be used by cultural practitioners and industry stakeholders alike to gain a better understanding of how consumers make their cultural experience good purchasing decisions. Ideas for further research are also provided.Mode of access: World wide web1 online resource (243 pages) illustrations (some colour, portraits (some colour
Hierarchy and gender in the emergency room: pragmatics and translation choices in the Japanese version of the television series ER
No full textTheoretical thesis.Bibliography: pages 265-285.Chapter 1. Introduction -- Chapter 2. Background and history of audiovisual translation -- Chapter 3. Hierarchy in the hospital -- Chapter 4. Characters and images -- Chapter 5. Methodology -- Chapter 6. Findings from the first phase of the study : part 1-- Chapter 7. Findings from the first phase of the study : part 2 -- Chapter 8. Findings from the second phase of the study -- Chapter 9. Discussion and conclusion --References -- Appendices.The advent of digital media products has enabled international audiences to enjoy TV dramas and films in a variety of languages. The present study focuses on the American TV drama ER, which is commercially available in Japanese on a DVD that includes both a dubbed and subtitled version. Because both dubbing and subtitling impose constraints on the process of translation, it is a demanding task for audiovisual (AV) translators to make translation choices within these restrictions. AV translators also need to take into account differences between the source culture and the target culture, including aspects of social structure and interpersonal relationships that can impact upon the approach to translation of the characters’ utterances.This study aims to investigate how translation choices affect the aspects of institutional hierarchy/power and gender in the original version (source text) of episodes of the American TV drama ER, as projected in the Japanese dubbed and subtitled versions (target texts). It also examines the impact of these particular translation choices on the images of the characters. The study consists of two phases. The first phase is a comparative textual analysis of extracts from the English original and the Japanese translated episodes of ER, focusing on address forms (including second-person pronouns) and the use of gender-associated sentence final forms (GASFFs) as pragmatic and gender markers. In the second phase of the study, a group of English speakers and a group of Japanese speakers watched an episode of ER in their respective first languages, and completed a survey and short follow-up interviews, which focused on the impressions of the characters (character images) formed while watching the episode.The first phase of the study reveals that linguistic markers of hierarchy, power and gender were more clearly displayed in the Japanese versions than in the original English version. This difference could be attributed to the effect of the choice of second-person pronouns and the use of gender-associated sentence final forms (GASFFs) in the Japanese versions. In some scenes, they also appear to contribute to the character images that were portrayed; and this was further investigated in the second phase.Survey data from the second phase of the study reveals few differences between the groups of English and Japanese speakers in terms of the character images that they perceived. Some of the comments in the follow-up interviews with the Japanese-speaking audience participants suggest that the images formed were influenced by the participants’ ‘gender filter’, which was in turn influenced by their generation and life experience. As participants made limited observations on the details of the Japanese used by characters in the drama, it is possible that their appraisals of the characters’ images were made at a subconscious level.By relating the finds from both the first and second phases, it is possible to conclude that pragmatic markers such as address forms including second person pronouns and gender-associated sentence final forms did not (at least on their own) determine the character image perceived by each viewer in this study.Although intercultural dimensions of AVT are important, there have been relatively few comparative studies that examine the pragmatics between Japanese text and English text. By drawing on dual perspectives gained from an analysis of linguistic features and audience impressions, the present study provides a model for researching AVT that can be refined and developed in future studies.Mode of access: World wide web1 online resource (xvi, 290 pages) table
Employment choice and ownership structure in transitional China
No full textThis paper investigates the determinants of employment choice of rural migrant workers across state-owned enterprises (SOEs) and various subtypes of non-state owned enterprises (non-SOEs) by taking into account of the unobservable characteristics that link the choice to migrate with the choice of employer. Using pooled cross-section data for 1995 and 2002, the results indicate that the decisions for migration and the choice of employment are related, suggesting that estimating employment choices without considering migration status leads to biased estimates. We find that both higher paid wages and broader pension benefits are major determinants of employment choice. Of these, pension benefits have a larger impact than high-level wages in increasing the employment probability for either type of enterprise.20 page(s
