No description available.

No description available.

No description available.

No description available.

No description available.

Ubiquitous computing aims to make human-computer interaction as naturalistic and functionally invisible as possible through embedding computing potential within a particular context to support human activity. However, much of ubiquitous computing research is focussed on technical innovation due to the challenges involved with deploying embedded computing, thereby reducing the commitment to the philosophical ideals of ubiquitous computing in research. This dissertation describes the investigation of a participatory approach to technically-complex research in order to understand how our view of the engineering and human challenges changes when the two are approached hand-in-hand. The domain chosen for this system was a dental surgery. Dentistry involves a complex workspace with computer interaction constrained by surgery hygiene. Ubiquitous computing offers a compelling interaction alternative to the keyboard and mouse paradigm in such an environment. A multi-method approach that employed ethnographic research and design prototyping was undertaken with dentists from several different private practices. A series of field studies used ethnographic methods such as observation and interview. Design events explored prototypes with activities such as design games, contextual interviews, role-playing and contextual prototyping. Activities were devised with the aim of providing a level playing field, whereby both designers and participants feel they can contribute equally, with their respective disciplinary knowledge. It was found that methods needed to be carefully chosen, devised and managed, in order to communicate complex concepts with participants and to constrain the design to technically feasible options. The thesis examines the design problem from the perspectives of a variety of different stakeholders within a participatory design framework, reflected upon by means of human-centred action research. Data was gathered through design speculations and observation, and explored using methods such as the Video Card Game and Video Interaction Analysis. Fieldwork was analysed using a multi-stage qualitative analysis process which informed further design collaboration with participants. The analysis of data gathered during design studies with dentists also contributed to the development of a prototype system to validate methodological contributions. The resulting prototype utilised off-the-shelf hardware and software which allowed for innovative customisation and development. In-situ prototyping (defined by the author as “participatory bootstrapping”) and a comprehensive knowledge of the domain afforded the creative application of technology. In addition to contributing to the prototype design, the interpretive understandings drawn from analysis identified how technical ideas were presented and utilised by participants of the studies, and how best to engage busy professionals. The final outcomes of the research were a multimodal ubiquitous computing system for interacting within a dental surgery; the development and implementation of a variety of methods aimed at communicating technical concepts and eliciting user motivations, practices and concerns; and a set of design principles for engineers engaging in design of systems for human use. The research presented within this thesis is primarily part of the field of human-computer interaction, but provides evidence of how engineering development can be influenced by a user-centred participatory approach. The benefits that derive from inclusive methods of design are demonstrated by the evaluation of a prototype that employed such methods. The contribution of this thesis is to demonstrate and delineate methods for developing ubiquitous computing technologies for the context of human use. This led to a set of design principles for the engineering of systems for human use: 1. Technology needs to be robust and simple to appropriate. This allows users to give insights on technology developments and also to allow users to discover for themselves how they would use the technology. 2. An evolving and carefully considered set of methods are needed to elicit communication between practitioners and across disciplines. The gaps in understandings and the different representations that arise across the disciplines provide essential clues to next steps in design. These gaps and differences form tensions that can be exploited productively. 3. Context is important for determining which design steps to take. Rather than abstracting a problem in order to solve it, as is usual in engineering design, the problem should remain grounded in the context of use. It reveals what the real problems are that need to be solved rather than the imagined ones. This requires an appreciation of the situated nature of action and of the variability of work. In turn it also requires an appreciation of what the human can and does do and what the machine should support. 4. Accountability in design is required. There is a fundamental tension between trying to make something work and seeing what really does work; specifically it is necessary to understand when automation is worth it in human machine systems. While engaged in the design process, engineers should ask how much technology should reconfigure human practices because of a useful outcome, rather than attempting to automate and converge devices for its own sake. A clear understanding of the constraints and workings of the work space needs to be balanced with the understandings of the limitations of the technology in order to design a system that improves work practice and empowers the practitioner.

Power transformers are important and expensive elements within the electric power transmission and distribution utilities. Since these equipments are connected in series to the network, any inadvertent failures would cause catastrophic interruptions to the power supply. As such, it is extremely critical for the power transformer to operate continuously in order to maintain a reliable and efficient electricity supply. Ageing or defects in power transformer has a root in its insulation structure and this has always been a well-known fact. For many years, mineral oil impregnated cellulose paper (OIP) has been the choice of insulation for power transformers due to its excellent dielectric properties as well as its inexpensive price. During the course of operation, the dielectric properties of OIP insulation inevitably deteriorate due to singularly or a combination of stresses such as thermal, electrical, mechanical, chemical as well as environmental stresses. Degradation of power transformer insulation is an irreversible process and has been encountered by all power utilities around the world. However, replacing a power transformer simply by its age is impractical and uneconomical. With the increase in the population of ageing power transformers, there is an urgent need to evaluate the condition of transformer insulation so as to facilitate the planning for refurbishment or replacement of the equipment in a more appropriate manner. To address this issue, many techniques involving both chemical and electrical methods have been developed to monitor the insulation condition of oil-filled power transformers. However, some of these techniques are destructive by nature and some of them are unable to assess the insulation condition accurately. With the advancement in technology over the years, newer diagnostic methods in time and frequency domains have been developed in recent years to assess the insulation condition based on their dielectric responses. One of the newly developed methods is known as Frequency Domain Spectroscopy (FDS) measurement and it monitors the insulation condition by measuring the diagnostic parameters as a function of frequency ranging from 0.1mHz to 1kHz. The primary focus of this thesis is to adopt FDS technique to study the effects of several deterioration factors on the dielectric response of transformer insulation, so as to develop a better understanding between FDS technique and the condition of transformer insulation. To study the effects of moisture and temperature, FDS measurements were performed on a CIGRE model transformer at various moisture concentrations and temperature levels. From the experimental results, moisture and temperature have significant impacts on the dielectric response of transformer insulation. In addition to constant temperature, FDS measurements were also performed during transient temperature conditions to investigate the effects of transient temperature on the dielectric response of transformer insulation. An empirical relationship between the dielectric response produced from transient and steady temperature conditions was able to be established from the experimental results. A novel approach to study the effects of geometrical parameters was also part of this research work. An insulation model has been designed and fabricated for the purpose of this study. FDS measurements were conducted on the insulation model with different configurations of barriers, spacers and oil volume. The results showed that geometrical parameters did have an impact on the dielectric response of transformer insulation. The secondary diagnostic technique used in this research is Polarisation and Depolarisation Current (PDC) measurement and the purpose of using this method is to explore the feasibility of reducing the total PDC measurement duration as well as to determine the optimum measurement time for PDC.

Ubiquitous computing aims to make human-computer interaction as naturalistic and functionally invisible as possible through embedding computing potential within a particular context to support human activity. However, much of ubiquitous computing research is focussed on technical innovation due to the challenges involved with deploying embedded computing, thereby reducing the commitment to the philosophical ideals of ubiquitous computing in research. This dissertation describes the investigation of a participatory approach to technically-complex research in order to understand how our view of the engineering and human challenges changes when the two are approached hand-in-hand. The domain chosen for this system was a dental surgery. Dentistry involves a complex workspace with computer interaction constrained by surgery hygiene. Ubiquitous computing offers a compelling interaction alternative to the keyboard and mouse paradigm in such an environment. A multi-method approach that employed ethnographic research and design prototyping was undertaken with dentists from several different private practices. A series of field studies used ethnographic methods such as observation and interview. Design events explored prototypes with activities such as design games, contextual interviews, role-playing and contextual prototyping. Activities were devised with the aim of providing a level playing field, whereby both designers and participants feel they can contribute equally, with their respective disciplinary knowledge. It was found that methods needed to be carefully chosen, devised and managed, in order to communicate complex concepts with participants and to constrain the design to technically feasible options. The thesis examines the design problem from the perspectives of a variety of different stakeholders within a participatory design framework, reflected upon by means of human-centred action research. Data was gathered through design speculations and observation, and explored using methods such as the Video Card Game and Video Interaction Analysis. Fieldwork was analysed using a multi-stage qualitative analysis process which informed further design collaboration with participants. The analysis of data gathered during design studies with dentists also contributed to the development of a prototype system to validate methodological contributions. The resulting prototype utilised off-the-shelf hardware and software which allowed for innovative customisation and development. In-situ prototyping (defined by the author as “participatory bootstrapping”) and a comprehensive knowledge of the domain afforded the creative application of technology. In addition to contributing to the prototype design, the interpretive understandings drawn from analysis identified how technical ideas were presented and utilised by participants of the studies, and how best to engage busy professionals. The final outcomes of the research were a multimodal ubiquitous computing system for interacting within a dental surgery; the development and implementation of a variety of methods aimed at communicating technical concepts and eliciting user motivations, practices and concerns; and a set of design principles for engineers engaging in design of systems for human use. The research presented within this thesis is primarily part of the field of human-computer interaction, but provides evidence of how engineering development can be influenced by a user-centred participatory approach. The benefits that derive from inclusive methods of design are demonstrated by the evaluation of a prototype that employed such methods. The contribution of this thesis is to demonstrate and delineate methods for developing ubiquitous computing technologies for the context of human use. This led to a set of design principles for the engineering of systems for human use: 1. Technology needs to be robust and simple to appropriate. This allows users to give insights on technology developments and also to allow users to discover for themselves how they would use the technology. 2. An evolving and carefully considered set of methods are needed to elicit communication between practitioners and across disciplines. The gaps in understandings and the different representations that arise across the disciplines provide essential clues to next steps in design. These gaps and differences form tensions that can be exploited productively. 3. Context is important for determining which design steps to take. Rather than abstracting a problem in order to solve it, as is usual in engineering design, the problem should remain grounded in the context of use. It reveals what the real problems are that need to be solved rather than the imagined ones. This requires an appreciation of the situated nature of action and of the variability of work. In turn it also requires an appreciation of what the human can and does do and what the machine should support. 4. Accountability in design is required. There is a fundamental tension between trying to make something work and seeing what really does work; specifically it is necessary to understand when automation is worth it in human machine systems. While engaged in the design process, engineers should ask how much technology should reconfigure human practices because of a useful outcome, rather than attempting to automate and converge devices for its own sake. A clear understanding of the constraints and workings of the work space needs to be balanced with the understandings of the limitations of the technology in order to design a system that improves work practice and empowers the practitioner.

This thesis is unusual in that it tries to solve a problem that exists between two widely separated disciplines: the humanities (and to some extent also linguistics) on the one hand and information science on the other. Chapter 1 explains why it is essential to strike a balance between study of the solution and problem domains. Chapter 2 surveys the various models of cultural heritage text, starting in the remote past, through the coming of the digital era to the present. It establishes why current models are outdated and need to be revised, and also what significance such a revision would have. Chapter 3 examines the history of markup in an attempt to trace how inadequacies of representation arose. It then examines two major problems in cultural heritage and lin- guistics digital texts: overlapping hierarchies and textual variation. It assesses previously proposed solutions to both problems and explains why they are all inadequate. It argues that overlapping hierarchies is a subset of the textual variation problem, and also why markup cannot be the solution to either problem. Chapter 4 develops a new data model for representing cultural heritage and linguistics texts, called a ‘variant graph’, which separates the natural overlapping structures from the content. It develops a simplified list-form of the graph that scales well as the number of versions increases. It also describes the main operations that need to be performed on the graph and explores their algorithmic complexities. Chapter 5 draws on research in bioinformatics and text processing to develop a greedy algorithm that aligns n versions with non-overlapping block transpositions in O(M N ) time in the worst case, where M is the size of the graph and N is the length of the new version being added or updated. It shows how this algorithm can be applied to texts in corpus linguistics and the humanities, and tests an implementation of the algorithm on a variety of real-world texts.

This thesis investigates the use of visual-motion information sampled through optical flow for the task of indoor obstacle avoidance on autonomous mobile robots. The methods focus on the practical use of optical flow and visual motion information in performing the obstacle avoidance task in real indoor environments. The methods serve to identify visual-motion properties that must be used in synergy with visual-spatial properties toward the goal of a complete robust visual-only obstacle avoidance system, as is evidently seen within nature. A review of vision-based obstacle avoidance techniques shows that early research mainly focused on visual-spatial techniques, which heavily rely on various assumptions of their environments to function successfully. On the other hand, more current research that looks toward the use of visual-motion information (sampled through optical flow) tends to focus on using optical flow in a subsidiary manner, and does not completely take advantage of the information encoded within an optical flow field. In the light of the current research limitations, this thesis describes two different approaches and evaluates their use of optical flow to perform the obstacle avoidance task. The first approach begins with the construction of a conventional range map using optical flow that stems from the structure-from-motion domain and the theory that optical flow encodes 3D environmental information under certain conditions. The second approach investigates optical flow in a causal mechanistic manner using machine learning of motor responses directly from optical flow - motivated from physical and behavioural evidence observed in biological creatures. Specifically, the second approach is designed with three main objectives in mind: 1) to investigate whether optical flow can be learnt for obstacle avoidance; 2) to create a system capable of repeatable obstacle avoidance performance in real-life environments; and 3) to analyse the system to determine what optical flow properties are actually being used for the motor control task. The range-map reconstruction results have demonstrated some good distance estimations through the use of a feature-based optical flow algorithm. However, the number of flow points were too sparse to provide adequate obstacle detection. Results froma differential-based optical flow algorithm helped to increase the density of flow points, but highlighted the high sensitivity of the optical flow field to the rotational errors and outliers that plague the majority of frames under real-life robot situations. Final results demonstrated that current optical flow algorithms are ill-suited to estimate obstacle distances consistently, as range-estimation techniques require an extremely accurate optical flow field with adequate density and coverage for success. This is a difficult problem within the optical flow estimation domain itself. In the machine learning approach, an initial study to examine whether optical flow can be machine learnt for obstacle avoidance and control in a simple environment was successful. However,there were certain problems. Several critical issues which arise with the use of a machine learning approach were highlighted. These included sample set completeness, sample set biases, and control system instability. Consequently, an extended neural network was proposed that had several improvements made to overcome the initial problems. Designing an automated system for gathering training data helped to eliminate most of the sample set problems. Key changes in the neural network architecture, optical flow filters, and navigation technique vastly improved the control system stability. As a result, the extended neural network system was able to successfully perform multiple obstacle avoidance loops in both familiar and unfamiliar real-life environments without collisions. The lap times of the machine learning approach were comparable to those of the laser-based navigation technique. The the machine learning approach was 13% slower in the familiar and 25% slower in the unfamiliar environment. Furthermore, through analysis of the neural network approach, flow magnitudes were revealed to be learnt for range information in an absolute manner, while flow directions were used to detect the focus of expansion (FOE) in order to predict critical collision situations and improve control stability. In addition, the precision of the flow fields was highlighted as an important requirement, as opposed to the high accuracy of flow vectors. For robot control purposes, image-processing techniques such as region finding and object boundary detection were employed to detect changes between optical flow vectors in the image space.