Abstract In 1999, the Electrical and Computer Engineering Department at the University of Canterbury started building their third electric vehicle (EV3) based on a TOYOTA MR2 with the goal of building a higher performance vehicle to match present combustion engined vehicles. The car is powered by 26 12volt sealed lead-acid batteries connected in series to achieve a nominal 312V DC source. A battery voltage equaliser is a device that draws energy from a higher charged battery, then discharges into a lower charged battery. The need for a voltage equaliser is principally due to the differences in cell chemistry, temperature gradients along the battery string and the ages of the batteries. During the charging or discharging process, some batteries reach their nominal voltage or reach deep discharge states before the others. Then if the charger keeps charging the batteries or the load keeps drawing energy from these batteries, it results in damage to the batteries. Therefore maintaining the charge level on each battery becomes important. In addition, it also improves the battery life and vehicle travelling range. This thesis details the analysis of three different types of battery equaliser, which are based on a 24W buck-boost converter, 192W buck-boost converter and 192W flyback converter. In this design, all converters are designed to work under current mode control with average of 2A. To make each converter install without significant effect on the performance and the cost, each converter is also built with the goals of being small, lightweight, cost effective, flexible for mounting, maintenance free and highly efficient. At the end, the prototype battery equalisation converters were designed, constructed and tested, and the efficiencies from each converter are measured around 90 ~ 92%. The experimental results show two banks of series connected batteries can be successfully equalised by the designed equaliser. This thesis covers the design, simulation and the construction procedures of this battery equaliser system, and also details on some considerations and possible future improvement that were found during the experimental test.

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This study focuses on the Muslim Turkish minority in Greece and the development of its educational rights. It starts with the 1923 Lausanne Treaty that established the minorityhood of the Muslim ummah for the former Ottoman territory and explores various aspects of Minority education between then and the end of the 2000s. While doing so, it treats these rights as individual rights with a collective aspect; some of the individual rights of minorities can only be enjoyed together with others. Also, it draws a direct correlation between the Minority's education and its rights. That is, in the case that the education level of the Minority was high, there was less discrimination against members of the Minority, since they had the linguistic skills, educational background and self-confidence to fight against violations of their rights by the host country, Greece. Also, it emphasizes the involvement of external actors in the development of Minority education in Western Thrace. Concerning the development of Minority education, this study argues that minorities' rights are not only ‘given' by host states but also ‘claimed' by members of minorities through various struggles at the local, national and international level. Also, as well as the Minority and the Greek state, various external agents, such as Turkey and the European Union, are also involved in the struggle between the Minority and the Greek state over the former's education. The impact of these agents on the survival of the Minority's educational rights was immense, particularly from the 1980s onwards. It was primarily the inclusion of these external actors that pushed Greece to change its discriminatory policy against the Minority in 1991. This study demonstrates that a number of the individual rights emanating from the Minority's Greek citizenship have only been recognized since 1991. Nonetheless, I conclude that in spite of some improvements, the Minority's difficulties in the realm of rights with collective aspects, such as education of Minority students in a bilingual environment, persist.

The implementation of Wavelength Division Multiplexing system (WDM) optical fibre transmission systems has the potential to realise this high capacity data rate exceeding 10 Tb/s. The ability to reconfigure optical networks is a desirable attribute for future metro applications where light paths can be set up or taken down dynamically as required in the network. The use of microelectronics in conjunction with photonics enables intelligence to be added to the high-speed capability of photonics, thus realising reconfigurable optical devices which can revolutionise optical telecommunications and many more application areas. In this thesis, we investigate and demonstrate the capability of Opto-VLSI processors to realise a reconfigurable WDM optical device of many functions, namely, optical multiband filtering, optical notch filtering, and reconfigurable-Optical-Add-Drop Multiplexing (ROADM). We review the potential technologies available for tunable WDM components, and discuss their advantages and disadvantages. We also develop a simple yet effective algorithm that optimises the performance of Opto-VLSI processors, and demonstrate experimentally the multi-function WDM devices employing Opto-VLSI processors. Finally, the feasibility of Opto-VLSI-based WDM devices in meeting the stringent requirements of the optical communications industry is discussed.

La péréquation française est devenue un enjeu fort des finances publiques locales. La croissance des moyens financiers et du nombre de dispositifs consacrés à la réduction des inégalités entre collectivités territoriales en est l’illustration. Malgré la mise en œuvre de péréquations nationales aux résultats encourageants, la cohérence et la complexité des mécanismes restent à parfaire. L’incapacité législative à contenir la péréquation dans un cadre stable et délimité n’est pas étrangère aux difficultés à appréhender la conciliation entre deux grands principes : la liberté et l’égalité. A ce titre, les grandes théories de la justice redistributive développées depuis le siècle des Lumières sont à considérer. Au contraire de la Loi fondamentale allemande, la Constitution française permet au législateur d’organiser très librement la solidarité inter-collectivités, d’autant que le juge constitutionnel, précurseur et gardien du droit à la péréquation, exerce en la matière, un contrôle incomplet au détriment de l’autonomie financière et fiscale des collectivités. A partir des fondements théoriques et positifs de la péréquation, un droit effectif et respectueux de l’autonomie locale reste à construire afin de corriger les insuffisances d’un système péréquateur récemment modifié par la réforme des lois de finances pour 2010 et 2011. / The financial equalisation system in France has become crucial in the management of local authorities. By way of illustration, there is an ongoing growth of financial resources, systems and plans of action to reduce inequalities between local governments and districts. Despite the encouraging results in the national equalisation implementation, its consistency and complexity mechanisms are to be enhanced. The disability to define freedom and equality contains the legislator in the design of stable and defined framework for equalisation. As such, the theory on a uniform distribution raised since the Age of Enlightenment, is to be considered. Unlike the German laws and regulation, the legislator is free to set up rules of financial interdependency among local authorities in the French Constitution. The constitutional judge, precursor and equalisation decision-maker, supervise an insufficient control to the detriment of financial and fiscal autonomy of local authorities. From the basis of equalisation benefits, there are some evident difficulties surrounding the limit of this system in respect to the degree of local authority’s financial autonomy. An operational review of both horizontal and vertical equalisation mechanisms, as well as the choice of redistribution criteria should be undertaken. The stakes are high to adjust and put right the shortcomings of the equalisation system, recently modified by a financial regulation reform for 2010 and 2011.

This thesis aims to deepen our understanding of the barriers that migrant children face in accessing quality education in their host country. It has identified gaps in the research on education of cross-border migrant children in a setting which promotes integration into the host community, and which does not use camps. The research is based in a small border town in northern South Africa and focuses on the recent influx of Zimbabwean migrants into South Africa as a result of political crisis and economic collapse in their homeland. This community was chosen because it is believed to be illustrative of the broader problems faced by cross-border migrant children. The thesis is structured around three central questions, focusing on (i) understanding who these migrant children are and their reasons for migration, (ii) the barriers they face in accessing quality basic education and (iii) the social and institutional networks that influence these children and the role the networks play in overcoming these barriers. The research examines the role of the state and the international community in the provision of support for this marginalised group. It further assesses the influence of social and institutional networks on migrants and the tactics they employ to overcome the barriers to educational success. The study used both quantitative and qualitative research methods, with the majority of data collected through an in-depth survey of 100 migrant children, between the ages of 6 and 17, and 35 parent/guardians. In addition, focus group discussions with teachers and interviews with 12 school principals were conducted. The views of members of the local Municipality involved with migrant children were also sought. The literature review revealed that, while there has been some research on barriers to education in camp settings, there is very limited research on educational access for migrant children integrating into host communities. This study has been able to contribute to this thin body of knowledge by demonstrating that as well as facing the traditional educational access barriers (lack of infrastructure, educational costs, enrolment requirements and social exclusion), integrating migrant children are faced with additional access barriers largely linked to their legal status (civil status, residence, status of guardians). The research identified the difficulties of obtaining the necessary legal status and some important shortcomings of the current migrant classification system. Getting the right documentation to obtain legal status often placed unreasonable burdens on the children and forced them into a catch 22 situation where they needed to return to their homeland to procure documents required for admission to school but doing so automatically invalidated the claims to refugee status. This particular study also highlighted the difficulty in classifying migrants who have fled from a country (Zimbabwe) that is not officially recognised as a conflict zone despite the characteristics of the Zimbabwean migrant situation being largely indistinguishable from classical conflict driven migration. The thesis concludes by recommending steps to change the definition and typology of migrants and points to the policy changes, with regard to support of migrant children that are required. The definitions should be changed to cater for the individual needs of the children so that legal and bureaucratic requirements do not present such an impediment to education. The thesis identified the large role of both the social and institutional networks of the migrant children in overcoming access barriers. This points to an area of valuable further research, which could provide a foundation for better policy development and implementation strategies that recognise the social and institutional dynamics that influence the decisions and choices made by migrant children and their parents.

Optimal decision directed equalization techniques for time dispersive communication channels are often too complex to implement. This thesis considers reduced complexity decision directed equalization that lowers complexity demands yet retains close to optimal performance. The first part of this dissertation consists of three reduced complexity algorithms based on the Viterbi Algorithm (VA) which are: the Parallel Trellis VA (PTVA); Time Reverse Reduced State Sequence Estimation (TR-RSSE); and Forward-Backward State Sequence Detection (FBSSD). The second part of the thesis considers structural modifications of the Decision Feedback Equalizer (DFE), which is a special derivative of the VA, specifically, optimal vector quantization for fractionally spaced DFEs, and extended stability regions for baud spaced DFEs using passivity analysis are investigated.¶ For a special class of sparse channels the VA can be decomposed over a number of independent parallel trellises. This decomposition will be called the Parallel Trellis Viterbi Algorithm and can have lower complexity than the VA yet it retains optimal performance. By relaxing strict sparseness constraints on the channel a sub-optimal approach is proposed which keeps complexity low and obtains good performance.¶ Reduced State Sequence Estimation (RSSE) is a popular technique to reduce complexity. However, its deficiency can be the inability to adequately equalize non-minimum phase channels. For channels that have energy peaks in the tail of the impulse response (post-cursor dominant) RSSE's complexity must be close to the VA or performance will be poor. Using a property of the VA which makes it invariant to channel reversal, TR-RSSE is proposed to extend application of RSSE to post-cursor dominant channels.¶ To further extend the class of channels suitable for RSSE type processing, FBSSD is suggested. This uses a two pass processing method, and is suited to channels that have low energy pre and post-cursor. The first pass generates preliminary estimates used in the second pass to aid the decision process. FBSSD can range from RSSE to TR-RSSE depending on parameter settings.¶ The DFE is obtained when the complexity of RSSE is minimized. Two characterizing properties of the DFE, which are addressed in this thesis, are feedback and quantization. A novel fractionally spaced (FS) DFE structure is presented which allows the quantizer to be generalized relative to the quantizer used in conventional FS-DFEs. The quantizer can be designed according to a maximum a posteriori criterion which takes into account a priori statistical knowledge of error occurrences. A radically different quantizer can be obtained using this technique which can result in significant performance improvements.¶ Due to the feedback nature of the DFE a form of stability can be considered. After a decision error occurs, a stable DFE will, after some finite time and in the absence of noise, operate error free. Passivity analysis provides sufficient conditions to determine a class of channels which insures a DFE will be stable. Under conditions of short channels and small modulation alphabets, it is proposed that conventional passivity analysis can be extended to account for varying operator gains, leading to weaker sufficient conditions for stability (larger class of channels).

Shingled Magnetic Recording (SMR) technology is important in the immediate need for expansion of magnetic hard disk beyond the limit of current disk technology. SMR provides a solution with the least change from current technology among contending technologies. Robust easy to implement Digital Signal Processing (DSP) techniques are needed to achieve the potentials of SMR. Current DSP techniques proposed border on the usage of Two Dimensional Magnetic Recording (TDMR) techniques in equalisation and detection, coupled with iterative error correction codes such as Low Density Parity Check (LDPC). Currently, Maximum Likelihood (ML) algorithms are normally used in TDMR detection. The shortcomings of the ML detections used is the exponential complexities with respect to the number of bits. Because of that, reducing the complexity of the processes in SMR Media is very important in order to actualise the deployment of this technology to personal computers in the near future. This research investigated means of reducing the complexities of equalisation and detection techniques. Linear equalisers were found to be adequate for low density situations. Combining ML detector across-track with linear equaliser along-track was found to provide low complexity, better performing alternative as compared to use of linear equaliser across track with ML along track. This is achieved if density is relaxed along track and compressed more across track. A gain of up to 10dB was achieved. In a situation with high density in both dimensions, full two dimensional (2D) detectors provide better performance. Low complexity full 2D detector was formed by serially concatenating two ML detectors, one for each direction, instead of single 2D ML detector used in other literature. This reduces complexity with respect to side interference from exponential to linear. The use of a single bit parity as run length limited code at the same time error correction code is also presented with a small gain of about 1dB at BER of 10^-5 recorded for the situation of high density.

The HF band of radio frequencies, from 3-30 MHz, is unique in its property that it is refracted by the ionosphere. This property allows long distance radio telecommunications around the world without requiring infrastructure. High frequency (HF) communication has been largely superseded by satellite and cellular technologies for day-to-day communications, due to the tight bandwidth constraints and technical difficulties inherent in using it. However there is still a need for HF communications devices where existing infrastructure is not available, such as in remote or polar locations, or in emergency situations due to natural disasters. This research is aimed at the development of an asymmetric HF communications link, with a battery-powered remote unit that transmits a small amount of data to a mains-powered base station. New technologies are identified and evaluated for use in the link, with the aim of reducing the power requirements of the remote unit. Error correction techniques are investigated. Low-density parity check (LDPC) codes, which are powerful codes used for forward error correction, are suggested for use in the link. Quasi-cyclic LDPC codes allow the low-power transmitter unit to use a computationally simple encoder based on feedback shift registers for generating the LDPC block codes cheaply. Semi-blind LDPC turbo equalisation is a powerful technique that can be used at the base station which utilises the structure of the LDPC code to encode the data stream. This equalises a received signal with a minimal amount of training data required, reducing the duty cycle of the remote unit. Hybrid automatic repeat request (HARQ) techniques are also investigated, which increase the throughput of a link when data repeats are required. A novel HARQ techniquewas created and proven to increase throughput in links with noise. As the proposed system may be deployed in remote locations, or locations where it might be difficult or undesirable to erect a proper HF antenna, a selection of buried antennas are characterised. A design for a remote unit is suggested. This unit was manufactured and used to test the capability of inexpensive, low power hardware to implement the proposed remote unit algorithms.