This thesis provides a thorough analysis of the theoretical foundations and properties of the Spectral Warping Transform. The spectral warping transform is defined as a time-domain-to-time-domain digital signal processing transform that shifts the frequency components of a signal along the frequency axis. The z -transform coefficients of a warped signal correspond to z -domain ‘samples’ of the original signal that are unevenly spaced along the unit circle (equivalently, frequency-domain coefficients of the warped signal correspond to frequency-domain samples of the original signal that are unevenly spaced along the frequency axis). The location of these unevenly spaced frequency-domain samples is determined by a z -domain mapping function. This function may be arbitrary, except that it must map the unit circle to the unit circle. It is shown that, in addition to the frequency location, the bandwidth, duration and amplitude of each frequency component of a signal are affected by spectral warping. Specifically, frequency components within bands that are expanded in frequency have shortened durations and larger amplitudes (conversely, components in compressed frequency bands become longer with smaller amplitudes). A property related to the expansion and compression of the duration of frequency components is that if a signal is time delayed (its digital sequence is prepended with zeroes) then each of the frequency components will have a different delay after warping. This time-domain separation phenomenon is useful for separating in time the frequency components of a signal. Such separation is employed in the generation of spectrally flat chirp signals. Because spectral warping will generally expand the duration of some frequency components within a signal, the transform must produce more output samples than there are (non-zero) input samples in order to avoid time-domain aliasing. A discussion of the necessary output signal length is presented. Particular attention is given to spectral warping using all-pass mapping function, which can be realised as a cascade of all-pass filters. There exists an efficient hardware implementation for this all-pass SW realisation [1, 2]. A proof-of-concept application-specific integrated circuit that performs the core operations required by this algorithm was developed. Another focus of the presented research is spectral warping using a piecewise- linear mapping function. This type of spectral warping has the advantage that the changes in frequency, duration and amplitude between the non-warped and warped signals are constant factors over fixed frequency bands. A matrix formulation of the spectral warping transformation is developed. It presents the spectral warping transform as a single matrix multiplication. The transform matrix is the product of the three matrices that represent three conceptual steps. The first step is to apply a discrete Fourier transform to the time-domain signal, providing the frequency-domain representation. Step two is an interpolation to produce the signal content at the desired new frequency samples. This interpolation effectively provides the frequency warping. The final step is an inverse DFT to transform the signal back into the time domain. A special case of the spectral warping transform matrix has the same result as a linear (finite-impulse-response) filter, showing that spectral warping is a generalisation of linear filtering. The conditions for the invertibility of the spectral warping transformation are derived. Several possible realisation of the SW transform are discussed. These include two realisation using parallel finite-impulse-response filter banks and a realisation that uses a cascade of infinite-impulse-response filters. Finally, examples of applications for the spectral warping transform are given. These include: non-uniform spectral analysis (and signal generation), approximate spectral analysis in the time domain, and filter design. This thesis concludes that the SW transform is a useful tool for the manipulation of the frequency content of digital signals, and is particularly useful when the frequency content of a signal (or the frequency response of a system) over a limited band is of interest. It is also claimed that the SW transform may have valuable applications for embedded mixed-signal testing.

No abstract available

The complex interactions between individuals, institutions and information and communications technologies (ICTs) have generated a growing body of research that seeks greater knowledge of the processes at work and their consequences. Situated firmly within this area, this thesis challenges the dominance of the generalised and largely technologically deterministic narratives within the field by seeking to constitute such knowledge in a different way. Geography provides a useful standpoint from which to challenge these narratives owing to its enduring engagement with time and space, concepts implicit in any discussion of ICTs effects. Emerging work on code space, transurbanism and timespace are specifically used to negate the persistent dualistic treatment of time and space which is argued to be hampering geographic research in this field. Methodologically drawing from a non representational style this thesis uses these emerging understandings to access the in between, a mental space of performance; which involves the process of drawing from tacit knowledge, cognitive perceptions of the spatial and temporal environment and emotions, in order to explore the conditions of possibility that individuals are becoming aware of through their interactions with ICTs. Four empirical interventions are used to ground these emerging understandings into the reality of everyday encounters with ICTs in Auckland, New Zealand. The first focuses on the role of local government in the development of Auckland’s ICT infrastructure, a complex and contingent process. The second concentrates on the provision of a Real Time Passenger Information System at Auckland bus stops, exposing individuals to new timespaces while waiting for the bus. The third considers students opinions of the e-learning mechanisms used in two first year geography courses. The final intervention examines the role ICTs play in South Africans and South Koreans imagining, negotiation and mediation of the migration process to Auckland. In conclusion, this thesis contributes to how geography constitutes knowledge about ICTs at three different levels. Empirically, the four interventions contribute grounded findings to the debates in the geographic literature over interactions with ICTs. Methodologically, the conditions of possibility institutional and individual actors are beginning to perceive through their encounters with ICTs are revealed as are the timespaces that may eventuate from these. Theoretically, to understand how the interactions between individuals and ICTs are performed this thesis demonstrates the need to interrogate the in between as a process, not just a gap or blank.

The complex interactions between individuals, institutions and information and communications technologies (ICTs) have generated a growing body of research that seeks greater knowledge of the processes at work and their consequences. Situated firmly within this area, this thesis challenges the dominance of the generalised and largely technologically deterministic narratives within the field by seeking to constitute such knowledge in a different way. Geography provides a useful standpoint from which to challenge these narratives owing to its enduring engagement with time and space, concepts implicit in any discussion of ICTs effects. Emerging work on code space, transurbanism and timespace are specifically used to negate the persistent dualistic treatment of time and space which is argued to be hampering geographic research in this field. Methodologically drawing from a non representational style this thesis uses these emerging understandings to access the in between, a mental space of performance; which involves the process of drawing from tacit knowledge, cognitive perceptions of the spatial and temporal environment and emotions, in order to explore the conditions of possibility that individuals are becoming aware of through their interactions with ICTs. Four empirical interventions are used to ground these emerging understandings into the reality of everyday encounters with ICTs in Auckland, New Zealand. The first focuses on the role of local government in the development of Auckland’s ICT infrastructure, a complex and contingent process. The second concentrates on the provision of a Real Time Passenger Information System at Auckland bus stops, exposing individuals to new timespaces while waiting for the bus. The third considers students opinions of the e-learning mechanisms used in two first year geography courses. The final intervention examines the role ICTs play in South Africans and South Koreans imagining, negotiation and mediation of the migration process to Auckland. In conclusion, this thesis contributes to how geography constitutes knowledge about ICTs at three different levels. Empirically, the four interventions contribute grounded findings to the debates in the geographic literature over interactions with ICTs. Methodologically, the conditions of possibility institutional and individual actors are beginning to perceive through their encounters with ICTs are revealed as are the timespaces that may eventuate from these. Theoretically, to understand how the interactions between individuals and ICTs are performed this thesis demonstrates the need to interrogate the in between as a process, not just a gap or blank.

The complex interactions between individuals, institutions and information and communications technologies (ICTs) have generated a growing body of research that seeks greater knowledge of the processes at work and their consequences. Situated firmly within this area, this thesis challenges the dominance of the generalised and largely technologically deterministic narratives within the field by seeking to constitute such knowledge in a different way. Geography provides a useful standpoint from which to challenge these narratives owing to its enduring engagement with time and space, concepts implicit in any discussion of ICTs effects. Emerging work on code space, transurbanism and timespace are specifically used to negate the persistent dualistic treatment of time and space which is argued to be hampering geographic research in this field. Methodologically drawing from a non representational style this thesis uses these emerging understandings to access the in between, a mental space of performance; which involves the process of drawing from tacit knowledge, cognitive perceptions of the spatial and temporal environment and emotions, in order to explore the conditions of possibility that individuals are becoming aware of through their interactions with ICTs. Four empirical interventions are used to ground these emerging understandings into the reality of everyday encounters with ICTs in Auckland, New Zealand. The first focuses on the role of local government in the development of Auckland’s ICT infrastructure, a complex and contingent process. The second concentrates on the provision of a Real Time Passenger Information System at Auckland bus stops, exposing individuals to new timespaces while waiting for the bus. The third considers students opinions of the e-learning mechanisms used in two first year geography courses. The final intervention examines the role ICTs play in South Africans and South Koreans imagining, negotiation and mediation of the migration process to Auckland. In conclusion, this thesis contributes to how geography constitutes knowledge about ICTs at three different levels. Empirically, the four interventions contribute grounded findings to the debates in the geographic literature over interactions with ICTs. Methodologically, the conditions of possibility institutional and individual actors are beginning to perceive through their encounters with ICTs are revealed as are the timespaces that may eventuate from these. Theoretically, to understand how the interactions between individuals and ICTs are performed this thesis demonstrates the need to interrogate the in between as a process, not just a gap or blank.

The complex interactions between individuals, institutions and information and communications technologies (ICTs) have generated a growing body of research that seeks greater knowledge of the processes at work and their consequences. Situated firmly within this area, this thesis challenges the dominance of the generalised and largely technologically deterministic narratives within the field by seeking to constitute such knowledge in a different way. Geography provides a useful standpoint from which to challenge these narratives owing to its enduring engagement with time and space, concepts implicit in any discussion of ICTs effects. Emerging work on code space, transurbanism and timespace are specifically used to negate the persistent dualistic treatment of time and space which is argued to be hampering geographic research in this field. Methodologically drawing from a non representational style this thesis uses these emerging understandings to access the in between, a mental space of performance; which involves the process of drawing from tacit knowledge, cognitive perceptions of the spatial and temporal environment and emotions, in order to explore the conditions of possibility that individuals are becoming aware of through their interactions with ICTs. Four empirical interventions are used to ground these emerging understandings into the reality of everyday encounters with ICTs in Auckland, New Zealand. The first focuses on the role of local government in the development of Auckland’s ICT infrastructure, a complex and contingent process. The second concentrates on the provision of a Real Time Passenger Information System at Auckland bus stops, exposing individuals to new timespaces while waiting for the bus. The third considers students opinions of the e-learning mechanisms used in two first year geography courses. The final intervention examines the role ICTs play in South Africans and South Koreans imagining, negotiation and mediation of the migration process to Auckland. In conclusion, this thesis contributes to how geography constitutes knowledge about ICTs at three different levels. Empirically, the four interventions contribute grounded findings to the debates in the geographic literature over interactions with ICTs. Methodologically, the conditions of possibility institutional and individual actors are beginning to perceive through their encounters with ICTs are revealed as are the timespaces that may eventuate from these. Theoretically, to understand how the interactions between individuals and ICTs are performed this thesis demonstrates the need to interrogate the in between as a process, not just a gap or blank.

The growth of interactive multimedia (IMM) applications is one of the major driving forces behind the swift evolution of next-generation wireless networks where the traffic is expected to be varying and widely diversified. The amalgamation of multimedia applications on high-speed wireless networks is somewhat a natural evolution. Wireless local area network (WLAN) was initially developed to carry non-real time data. Since this type of traffic is bursty in nature, the channel access schemes were based on contention. However real time traffic (e.g. voice, video and other IMM applications) are different from this traditional data traffic as they have stringent constraints on quality of service (QoS) metrics like delay, jitter and throughput. Employing contention free channel access schemes that are implemented on the point coordination function (PCF), as opposed to the numerous works on the contending access schemes, is the plausible and intuitive approach to accommodate these innate requirements. Published researches show that works have been done on improving the distributed coordination function (DCF) to handle IMM traffic. Since the WLAN traffic today is a mix of both, it is only natural to utilize both, DCF and PCF, in a balanced manner to leverage the inherent strengths of each of them. We saw a scope in this technique and develop a scheme that combines both contention and non-contention based phases to handle heterogeneous traffic in WLAN. Standard access scheme, like 802.11e, improves DCF functionality by trying to emulate the functions of PCF. Researchers have made a multitude of improvements on 802.11e to reduce the costs of implementing the scheme on WLAN. We explore improving the PCF, instead, as this is more stable and implementations would be less costly. The initial part of this research investigates the effectiveness of the point coordination function (PCF) for carrying interactive multimedia traffic in WLAN. The performance statistics of IMM traffic were gathered and analyzed. Our results showed that PCF-based setup for IMM traffic is most suitable for high load scenarios. We confirmed that there is a scope in improving IMM transmissions on WLAN by using the PCF. This is supported by published researches on PCF related schemes in carrying IMM traffic on WLAN. Further investigations, via simulations, revealed that partitioning the superframe (SF) duration according to the need of the IMM traffic has considerable impact on the QoS of the WLAN. A theoretical model has been developed to model the two phases, i.e., PCF and DCF, of WLAN medium access control (MAC). With this model an optimum value of the contention free period (CFP) was calculated to meet the QoS requirement of IMM traffic being transmitted. Treating IMM traffic as data traffic or equating both IMM and non-IMM together could compromise a fair treatment that should be given to these QoS sensitive traffic. A self-adaptive scheme, called MAC with Dynamic Superframe Selection (MDSS) scheme, generates an optimum SF configuration according to the QoS requirements of traversing IMM traffic. That particular scheme is shown to provide a more efficient transmission on WLAN. MDSS maximizes the utilization of CFP while providing fairness to contention period (CP). The performance of MDSS is compared to that of 802.11e, which is taken as the benchmark for comparison. Jitter and delay result for MDSS is relatively lower while throughput is higher. This confirms that MDSS is capable of making significant improvement to the standard access scheme.

The quality of Machine Translation (MT) can often be poor due to it appearing incoherent and lacking in fluency. These problems consist of word ordering, awkward use of words and grammar, and translating text too literally. However we should not consider translations such as these failures until we have done our best to enhance their quality, or more simply, their fluency. In the same way various processes can be applied to touch up a photograph, various processes can also be applied to touch up a translation. This research outlines the improvement of MT quality through the application of Fluency Enhancement (FE), which is a process we have created that reforms and evaluates text to enhance its fluency. We have tested our FE process on our own MT system which operates on what we call the SAM fundamentals, which are as follows: Simplicity - to be simple in design in order to be portable across different languages pairs, Adaptability - to compensate for the evolution of language, and Multiplicity - to determine a final set of translations from as many candidate translations as possible. Based on our research, the SAM fundamentals are the key to developing a successful MT system, and are what have piloted the success of our FE process.

The complex interactions between individuals, institutions and information and communications technologies (ICTs) have generated a growing body of research that seeks greater knowledge of the processes at work and their consequences. Situated firmly within this area, this thesis challenges the dominance of the generalised and largely technologically deterministic narratives within the field by seeking to constitute such knowledge in a different way. Geography provides a useful standpoint from which to challenge these narratives owing to its enduring engagement with time and space, concepts implicit in any discussion of ICTs effects. Emerging work on code space, transurbanism and timespace are specifically used to negate the persistent dualistic treatment of time and space which is argued to be hampering geographic research in this field. Methodologically drawing from a non representational style this thesis uses these emerging understandings to access the in between, a mental space of performance; which involves the process of drawing from tacit knowledge, cognitive perceptions of the spatial and temporal environment and emotions, in order to explore the conditions of possibility that individuals are becoming aware of through their interactions with ICTs. Four empirical interventions are used to ground these emerging understandings into the reality of everyday encounters with ICTs in Auckland, New Zealand. The first focuses on the role of local government in the development of Auckland’s ICT infrastructure, a complex and contingent process. The second concentrates on the provision of a Real Time Passenger Information System at Auckland bus stops, exposing individuals to new timespaces while waiting for the bus. The third considers students opinions of the e-learning mechanisms used in two first year geography courses. The final intervention examines the role ICTs play in South Africans and South Koreans imagining, negotiation and mediation of the migration process to Auckland. In conclusion, this thesis contributes to how geography constitutes knowledge about ICTs at three different levels. Empirically, the four interventions contribute grounded findings to the debates in the geographic literature over interactions with ICTs. Methodologically, the conditions of possibility institutional and individual actors are beginning to perceive through their encounters with ICTs are revealed as are the timespaces that may eventuate from these. Theoretically, to understand how the interactions between individuals and ICTs are performed this thesis demonstrates the need to interrogate the in between as a process, not just a gap or blank.

This dissertation claims that the reciprocal exchange of voice—an element for constructing community and strengthening political recognition—may be fostered in small-scale farming communities by (1) the appropriation and transformation of information and communications technologies, (2) artistic intervention, and (3) cross-community research. This study contributes to participatory research methodologies, particularly those that seek to tackle the diverse challenges faced by small-scale farmers from a broad, complex perspective. The main issue identified in this dissertation is as follows: The hegemony of economic behaviors, which stands as a cornerstone of neoliberal capitalism, constitutes the latest stage of a historical process in which the voices of small-scale farmers seem to have been progressively and systematically silenced, their traditional practices largely invalidated, and their reciprocal forms of social, political, and economic organization marginalized. The purpose of this study was to explore whether an open-ended, sociotechnical methodology could be designed and applied in small-scale farming communities with the aim of strengthening their reciprocal practices while amplifying the voices of their members. The author's research addressed the question of how the role of information and communications technologies can contribute to the creation of enabling environments in which subsistence farmers may exercise their own values and make their voices heard. Another goal was to study whether the reciprocal exchange of voice could relate to the construction and dissemination of a knowledge commons and improve the resilience of small-scale farmers in the context of complex and pressing challenges such as anthropogenic climate change. Consequently, the ERV (Enabling Reciprocal Voice) Methodology was developed and applied in small-scale farming communities in order to respond to the questions of this study. The ERV Methodology sought to redefine the modes of usage of information and communications technologies in order to help communities establish a shared communicational praxis and strengthen their reciprocal relations. The ERV Methodology stands in contrast with the technological determinism found in the purely solutionist, short-term initiatives that are generally implemented in small-scale farming communities. Instead of offering rapid solutions to isolated problems, the ERV Methodology sought to consolidate the social networks of farmers through online and offline interaction. The case studies examined in this dissertation were carried out in two small-scale farming communities in Tanzania and Mexico. Following the ERV Methodology, mobile phones and the Internet were used by farmers in those communities as tools for the collaborative creation of a knowledge commons focused on local agriculture. It was found that the ERV Methodology, carried out as artistic intervention, may encourage technological appropriation, induce reciprocity, and amplify voice under certain sociotechnical conditions. These findings suggest that such a methodology might benefit farmers by becoming a significant aid to increase their resilience and their capacity to face complex challenges in the longer term. However, another conclusion was that the ERV Methodology should be applied carefully, with a strong awareness of the local context, and that greater efforts must be made in order to integrate other communities, such as local authorities and scientific researchers, into the reciprocal dynamics enabled by the methodology.