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(2009)ThesisA large scale electricity industry can be regarded as a complex technological system that must address many challenges including adapting to climate change, responding to climate change mitigation policy, operating in an environment where there is increased global competition for primary energy resources and addressing the issue of interconnections to other electricity industries. The operation of an electricity industry must account for not only the connection and subsequent operation of physical components and systems but also the uncertain consequences of human decision-making. This thesis adopts an industry-level approach to defining, analysing and organising formal decision-making processes in an electricity industry, leading to the concept of a decision-making framework for an electricity industry. The approach also identifies the importance of reconciling the different decision-making methodologies and different decision-making styles associated with different disciplines that influence the operation and evolution of an electricity industry. In this way, the uncertain consequences of decision-making within an electricity industry can be narrowed to those outcomes that society deems acceptable. The industry-level approach is sufficiently generic to be applied to a number of specific and diverse case studies that focus on short-term operational issues in an electricity industry. Among others, the case studies include the integration of non-storable stochastic primary energy resources into an electricity industry, a security envelope to protect an electricity industry against frequency collapse following separation contingencies and the interface between a security decision-making regime and a commercial decision-making regime in an electricity industry. The application of the industry-level approach in the case studies demonstrates the importance of designing interfaces and specifying boundaries between formal decision-making processes that constrain, inform and coordinate different sets of decisions-makers in an electricity industry. The thesis concludes that developing and applying a coherent decision-making framework for an electricity industry provides an appropriate balance between industry robustness against a wide range of uncertainties and flexibility to address new challenges as they arise.
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(2009)ThesisRegenerative biology seeks to understand the molecular mechanisms that differentiate several animals with the ability to regenerate tissues. An approach to evaluate these mechanisms is via a comparative analysis of regeneration-competent versus regeneration-deficient tissues. This thesis analyses the regenerative capacity in the axolotl blastema during the dedifferentiation phase. Currently, there is an equivocal understanding of the molecular factors expressed during the regenerative process and further analysis is warranted. Comprehensive profiles of the proteins expressed during this process are presented. Nerve derived factors such as neuregulin-1 and neurotrophin-3 were identified in the axolotl blastema during the time of dedifferentiation. Additionally, this study investigated if there are any correlation between the nerve determinants, such as neurotrophins, from the regenerating blastema and neurogenesis that occurs throughout the lifespan of mammals in the olfactory system. This was achieved by comparing the expression proteomes of the regeneration-competent axolotl and olfactory ensheathing cells. Collectively, the study proposes that there is an influence by neurotrophins on neurogenesis in the olfactory system that are comparable to the dynamic nerve signaling networks that occur in the axolotls regenerating limb. It provides a window into the complex signaling pathways during the two processes that can be clinically translated to further develop better therapeutic strategies that involve peripheral nervous tissue of the spinal cord. The current clinical outcomes usually result in limited functional restoration. One of the most promising techniques is to induce a regenerative capacity in the affected tissues using a tissue engineering strategy. The combination of factors identified may serve as candidates to augment in vivo peripheral nerve microenvironments and to achieve a regenerative capacity in human tissues. These neurotrophins should be considered for regenerative medicine applications to induce regenerative competence in human peripheral nerve tissues.
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(2009)ThesisEngineering complex systems and New Product Development (NPD) are major challenges for contemporary engineering design and must be studied at three levels of: Products, Processes and Organizations (PPO). The science of complexity indicates that complex systems share a common characteristic: they are robust yet fragile. Complex and large scale systems are robust in the face of many uncertainties and variations; however, they can collapse, when facing certain conditions. This is so since complex systems embody many subtle, intricate and nonlinear interactions. If formal modelling exercises with available computational approaches are not able to assist designers to arrive at accurate predictions, then how can we immunize our large scale and complex systems against sudden catastrophic collapse? This thesis is an investigation into complex product design. We tackle the issue first by introducing a template and/or design methodology for complex product design. This template is an integrated product design scheme which embodies and combines elements of both design theory and organization theory; in particular distributed (spatial and temporal) problem solving and adaptive team formation are brought together. This design methodology harnesses emergence and innovation through the incorporation of massive amount of numerical simulations which determines the problem structure as well as the solution space characteristics. Within the context of this design methodology three design methods based on measures of complexity are presented. Complexity measures generally reflect holistic structural characteristics of systems. At the levels of PPO, correspondingly, the Immunity Index (global modal robustness) as an objective function for solutions, the real complexity of decompositions, and the cognitive complexity of a design system are introduced These three measures are helpful in immunizing the complex PPO from chaos and catastrophic failure. In the end, a conceptual decision support system (DSS) for complex NPD based on the presented design template and the complexity measures is introduced. This support system (IMMUNE) is represented by a Multi Agent Blackboard System, and has the dual characteristic of the distributed problem solving environments and yet reflecting the centralized viewpoint to process monitoring. In other words IMMUNE advocates autonomous problem solving (design) agents that is the necessary attribute of innovative design organizations and/or innovation networks; and at the same time it promotes coherence in the design system that is usually seen in centralized systems.
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(2009)ThesisHazardous and recalcitrant pollutants in the environments have led to a great many environmental issues these days. Many researchers have focused on the approaches to treatment of these pollutants which contaminate environments such as soil, surface and groundwater. As an advanced oxidation processes (AOPs), sonolysis which is the oxidation technology involving the use of ultrasonic irradiation, has proven to be successful for the treatment and remediation of contaminated environments. In this thesis, hydrogen peroxide formation and formic acid degradation by ultrasonic irradiation of well-characterised solutions are described under various conditions in order to determinate reaction mechanism by which peroxide degradation and contaminant degradation occur. The effect of gas properties and frequency on hydrogen peroxide and formic acid degradation are examined. Experimental results obtained are analyzed in light of the reactions occurring. Successful mathematical modeling of the result s obtained confirms that, for the most part, hydrogen peroxide and formic degradation occur by free radical generation within bubbles with subsequent transfer of these radicals to the bubble-water interface where the majority of the degradation occurs. The effect of Fe(II) addition which can lead to Fenton reactions in the bulk solution are also investigated. Experimental and model results show that the heterogeneous reactions can enhance the degradation of formic acid in the presence of Fe(II). Oxidation of phenol by ultrasonic irradiation under a variety of initial conditions and solution environments is also described and validated by a simple kinetic model. The model developed will be useful for improving our understanding of free radicals behaviour and the interplay between free radical generation and contaminant degradation.
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(2009)ThesisThis research investigates the use of conducting polymer coatings on platinum (Pt) electrodes for use in neuroprostheses. Conducting polymers aim to provide an environment conducive to neurite outgrowth and attachment at the electrode sites, producing intimate contact between neural cells and stimulating electrodes. Conducting polymers were electropolymerised onto model Pt electrodes. Conventional polymers polypyrrole (PPy) and poly-3,4-ethylenedioxythiphene (PEDOT) doped with polystyrenesulfonate (PSS) and para-toluenesulfonate (pTS)were investigated. Improvement of material properties was assessed through the layering of polymers with multi-walled carbon nanotubes (MWNTs). The ability to incorporate cell attachment bioactivity into polymers was examined through the doping of PEDOT with anionic laminin peptides DCDPGYIGSR and DEDEDYFQRYLI. Finally, nerve growth factor (NGF), was entrapped in PEDOT during polymerisation and tested for neurite outgrowth bioactivity against the PC12 cell line. Each polymer modification was assessed for electrical performance over multiple reduction-oxidation cycles, conductivity and impedance spectroscopy, mechanical adherence and hardness, and biological response. Scanning electron microscopy was used to visualise film topography and x-ray photon spectroscopy was employed to examine chemical constitution of the polymers. For application of electrode coatings to neural prostheses, optimal bioactive conducting polymer PEDOT/pTS/NGF was deposited on electrode arrays intended for implantation. PC12s were used to assess the bioactivity of NGF functionalised PEDOT when electrode size was micronised. Flexibility of the design was tested by tailoring PEDOT bioactivity for the cloned retinal ganglion cell, RGC-5, differentiated via staurasporine. It was established that PEDOT films had superior electrical and cell growth characteristics, but only PPy was able to benefit from incorporation of MWNTs. Bioactive polymers were produced through inclusion of both laminin peptides and NGF, but the optimum film constitution was found to be PEDOT doped with pTS with NGF entrapped during electrodeposition. Application of this polymer to an implant device was confirmed through positive neurite outgrowth on vision prosthesis electrode arrays. The design was shown to be flexible when tailored for RGC-5s, with differentiation occurring on both PEDOT/pTS and PEDOT/DEDEDYFQRYLI. Conducting polymers demonstrate the potential to improve electrode-cell interactions. Future work will focus on the effect of electrical stimulation and design of bioactive polymers with improved cell attachment properties.
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(2009)ThesisWeb services are increasingly gaining acceptance as a framework for facilitating application-to-application interactions within and across enterprises. It is commonly accepted that a service description should include not only the interface, but also the business protocol supported by the service. The present work focuses on the formalization of the important category of protocols that include time-related constraints (called timed protocols), and the impact of time on compatibility and replaceability analysis. We formalized the following timing constraints: CInvoke constraints define time windows of availability while MInvoke constraints define expirations deadlines. We extended techniques for compatibility and replaceability analysis between timed protocols by using a semantic-preserving mapping between timed protocols and timed automata, leading to the novel class of protocol timed automata (PTA). Specifically, PTA exhibit silent transitions that cannot be removed in general, yet they are closed under complementation, making every type of compatibility or replaceability analysis decidable. Finally, we implemented our approach in the context of a larger project called ServiceMosaic, a model-driven framework for web service life-cycle management.
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(2009)ThesisWhile Application Specific Instruction Set Processors (ASIPs) have allowed designers to create processors with custom instructions to target specific applications, floating-point units (FPUs) are still instantiated as non-customizable general-purpose units, which if under utilized, wastes area and performance. However, customizing FPUs manually is a complex and time-consuming process. Therefore, there is a need for an automated custom FPU generation scheme. This thesis presents a methodology for generating application-specific FPUs customized at the instruction level, with integrated datapath merging to minimize area. The methodology reduces the subset of floating-point instructions implemented to the minimum required for the application. Datapath merging is then performed on the required datapaths to minimize area. Previous datapath merging techniques failed to consider merging components of different bit-widths and thus ignore the bit-alignment problem in datapath merging. This thesis presents a novel bit-alignment solution during datapath merging. In creating the custom FPU, the subset of floating-point instructions that should be implemented in hardware has to be determined. Implementing more instructions in hardware reduces the cycle count of the application, but may lead to increased delay due to multiplexers inserted on the critical path during datapath merging. A rapid design space exploration was performed to explore the trade-offs. By performing this exploration, a designer could determine the number of instructions that should be implemented as a custom FPU and the number that should be left for software emulation, such that performance and area meets the designer's requirements. Customized FPUs were generated for different Mediabench applications and compared to a fully-featured reference FPU that implemented all floating-point operations. Reducing the floating-point instruction set reduced the FPU area by an average of 55%. Performing instruction reduction and then datapath merging reduced the FPU area by an average of 68%. Experiments showed that datapath merging without bit-alignment achieved an average area reduction of 10.1%. With bit-alignment, an average of 16.5% was achieved. Bit-alignment proved most beneficial when there was a diverse mix of different bit-widths in the datapaths. Performance of Field-Programmable Gate Arrays (FPGAs) used for floating-point applications is poor due to the complexity of floating-point arithmetic. Implementing floating-point units on FPGAs consume a large amount of resources. Therefore, there is a need for embedded FPUs in FPGAs. However, if unutilized, they waste area on the FPGA die. To overcome this issue, a novel flexible multi-mode embedded FPU for FPGAs is presented in this thesis that can be configured to perform a wide range of operations. The floating-point adder and multiplier in the embedded FPU can each be configured to perform one double-precision operation or two single-precision operations in parallel. To increase flexibility further, access to the large integer multiplier, adder and shifters in the FPU is provided. It is also capable of floating-point and integer multiply-add operations. Benchmark circuits were implemented on both a standard Xilinx Virtex-II FPGA and on the FPGA with embedded FPU blocks. The implementations on the FPGA with embedded FPUs showed mean area and delay improvements of 5.2x and 5.8x respectively for the double-precision benchmarks, and 4.4x and 4.2x for the single-precision benchmarks.
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(2009)ThesisThe success of Web services comes from the benefits that it brings in reducing the cost and the time needed to develop data and applications by reusing them, and simplifying their integrations through standardization. However, standardization in Web services does not remove the need for adapters due to possible heterogeneity among service interface and protocol definitions. Moreover, the current service APIs are targeted toward professional programmers, but not accessible to a wider class of users without programming expertise, but would never the less like to build their own integrated applications. In this dissertation, we propose methods and tools to support both service developers and non-expert users in their data and application integration tasks. To support service developers, we propose a framework that enables rapid development of Web service adapters. We investigate particularly the problem of service adaptation focusing on business interface and protocol layers. Our study shows that many differences between business interfaces and protocols are recurring. We introduce mismatch patterns to capture these recurring differences and provide solutions to resolve them. We present the notion of adaptation aspects, which is based on the aspect-oriented programming paradigm, to enable rapid development and deployment of service adapters. We also present a comparative study between standalone and aspect-oriented adapters development. The study shows that the aspect-oriented approach is preferable in many cases, especially when adapters need to access internal states of services. The proposed approach is implemented in a prototype tool, which is used to illustrate how it simplifies adapters development through a case study. To support users without programming expertise, we propose a spreadsheet-based Web mashups development framework, which enables users to develop mashups in the popular spreadsheet environment. First, we provide a mechanism that makes structured data first class values of spreadsheet cells. Second, we propose a new component model that can be used to develop fairly sophisticated mashups, involving joining data sources and keeping spreadsheet data up to date. Third, to simplify mashup development, we provide a collection of spreadsheet-based mashup patterns that captures common Web data access and spreadsheet presentation functionalities. Users can reuse and customize these patterns to build spreadsheet-based Web mashups instead of developing them from scratch. Fourth, we enable users to manipulate structured data presented on spreadsheet in a drag-and-drop fashion. Finally, we have developed and tested a prototype tool to demonstrate the utility of the proposed framework.