Computer Science (Theses and Dissertations) http://hdl.handle.net/2262/117 2013-05-13T17:41:38Z 2013-05-13T17:41:38Z LAWLESS, SEAMUS http://hdl.handle.net/2262/62485 2012-03-02T14:02:54Z 2009-01-01T00:00:00Z

Title: Leveraging Content from Open Corpus Sources for Technology Enhanced Learning Author: LAWLESS, SEAMUS Abstract: As educators attempt to incorporate the use of educational technologies in course curricula, the lack of appropriate and accessible digital content resources acts as a barrier to adoption. Quality educational digital resources can prove expensive to develop and have traditionally been restricted to use in the environment in which they were authored. As a result, educators who wish to adopt these approaches are compelled to produce large quantities of high quality educational content. This can lead to excessive workloads being placed upon the educator, whose efforts are better exerted on the pedagogical aspects of eLearning design. The accessibility, portability, repurposing and reuse of digital resources thus became, and remain, major challenges. The key motivation of this research is to enable the utilisation of the vast amounts of accumulated knowledge and educational content accessible via the World Wide Web in Technology Enhanced Learning (TEL). This thesis proposes an innovative approach to the targeted sourcing of open corpus content from the WWW and the resource-level reuse of such content in pedagogically beneficial TEL offerings. The thesis describes the requirements, both educational and technical, for a tool-chain that enables the discovery, classification, harvesting and delivery of content from the WWW, and a novel TEL application which demonstrates the resource-level reuse of open corpus content in the execution of a pedagogically meaningful educational offering. Presented in this work are the theoretical foundations, design and implementation of two applications: the Open Corpus Content Service (OCCS); and the User-driven Content Retrieval, Exploration and Assembly Toolkit for eLearning (U-CREATe). To evaluate and validate this research, a detailed analysis of the different aspects of the research is presented, outlining and addressing the discovery, classification and harvesting of open corpus content from the WWW and open corpus content utilisation in TEL. This analysis provides confidence in the ability of the OCCS to generate collections of highly relevant open corpus content in defined subject areas. The analysis also provides confidence that the resource-level reuse of such content in educational offerings is possible, and that these educational offerings can be pedagogically beneficial to the learner. A novel approach to the sourcing of open corpus educational content for integration and reuse in TEL is the primary contribution to the State of the Art made by this thesis and the research described therein. This approach differs significantly from those used by current TEL systems in the creation of learning offerings and provides a service which is considerably different to that offered by general purpose web search engines. Description: PUBLISHED

2009-01-01T00:00:00Z CAULFIELD, DARREN http://hdl.handle.net/2262/58713 2011-08-16T14:08:11Z 2011-01-01T00:00:00Z

Title: Mean-Shift Tracking for Surveillance: Evaluations and Enhancements Author: CAULFIELD, DARREN Abstract: Mean-shift tracking is a technique for following an object of interest as it moves through a video sequence. It is a gradient ascent approach that models the image region to be tracked by its colour histogram. In this thesis, we apply mean shift in the domain of surveillance in order to track people as they walk through a scene. Our objectives are to evaluate the performance of the technique and subsequently to introduce modifications which make the method more robust, i.e., more likely to follow a designated target through an entire video sequence. We first compare mean shift to a standard template matching approach. The latter is found to be much more reliable, rarely losing track of its target, and so its performance serves as a baseline against which to measure the effects of our subsequent modifications to the basic mean-shift method. In an effort to improve the reliability of mean shift, we employ an existing technique – the use of multiple-part models – to introduce a degree of spatial structure into its histograms, mimicking one of the strengths of template matching. We further extend the method by exploiting background models of the scene, another widely used modification. Our innovation of combining the two enhancements, while not enabling mean shift to reach the performance of the template matching tracker, increases its reliability considerably. There are several parameters associated with any tracker. In the case of using the meanshift technique in the surveillance domain, we seek the optimal choices for the colour space in which it operates and the size of its model histograms, among other parameters. Once again, the evaluations allow us to improve the performance of the method. The greatest advantage of mean shift over other tracking techniques is arguably its computational efficiency (deriving from its gradient ascent nature), even if this comes at the expense of lower robustness. However, we succeed in developing a tracker based on normalised cross-correlation (the similarity measure at the heart of template matching) that also uses a gradient ascent optimisation strategy. The new approach is both fast and significantly more reliable than mean shift, calling into question the use of the latter technique. We also define an algorithm for verifying that the output of a tracker is trustworthy. Unlike our previous evaluations, the track validation approach does not require the use of ground truth data, and provides a semi-automated means of assessing the performance of any tracking method. It also allows our new gradient-based tracker to update its model in response to appearance changes in the target, further increasing the reliability of the method. Description: PUBLISHED

2011-01-01T00:00:00Z Woulfe, Muiris http://hdl.handle.net/2262/41259 2010-12-10T03:02:43Z 2010-01-01T00:00:00Z

Title: A Hybrid Software and Hardware System for Collision Detection Author: Woulfe, Muiris Abstract: Collision detection is a fundamental problem in myriad applications, spanning a wide variety of fields. Although the core concept is relatively straightforward, significant complexities result from the demand for interactive or real-time performance for ever-increasing workloads. In this thesis, a different approach is applied to the problem of collision detection. This approach consists of a hybrid software and hardware system that utilises the properties of both software and hardware to achieve an acceleration over the current state of the art. At its core, the system consists of a custom microarchitecture performing broad phase collision detection, with the narrow phase executing in software. The microarchitecture consists of a plurality of memories internal to the microarchitecture, which parallelise the input data. These data are then formed into pairs using a custom data access algorithm, before being processed using a parallel version of the all-pairs algorithm. Two equivalent microarchitectures are presented: the first is designed for microarchitecture platforms with highly constrained resources, while the second supports many more objects. Both designs are prototyped using a reconfigurable hardware platform known as a field-programmable gate array (FPGA). Despite the major advantages that can be achieved using this system, a question remains over how to deal with limitations on the size of internal memories in microarchitecture platforms. These limitations would significantly curtail the number of objects that could be processed by the microarchitectures. To answer this question, spatial partitioning is proposed. This partitions the environment into cells of appropriate size for processing by the microarchitecture. After the software reads a potentially colliding set (PCS) from the microarchitecture, narrow phase processing of the objects begins and this processing is overlapped with the microarchitecture’s processing of the subsequent cell. A framework for benchmarking collision detection algorithms is also presented. This framework is based on a physics engine, in order to accurately reflect scenarios found in many interactive applications, and includes a set of parameters that allow the creation of myriad practical benchmarks from a single generic benchmark. Collision detection algorithm developers can use the benchmark to rapidly determine which scenarios perform inefficiently with their algorithm. In addition, developers of applications utilising collision detection can recreate their scenarios using the benchmark to rapidly find the most efficient algorithm for those scenarios. Description: PUBLISHED

2010-01-01T00:00:00Z LAWLESS, SEAMUS http://hdl.handle.net/2262/39521 2011-02-17T18:04:59Z 2009-01-01T00:00:00Z

Title: Leveraging Content from Open Corpus Sources for Technology Enhanced Learning Author: LAWLESS, SEAMUS Abstract: As educators attempt to incorporate the use of educational technologies in course curricula, the lack of appropriate and accessible digital content resources acts as a barrier to adoption. Quality educational digital resources can prove expensive to develop and have traditionally been restricted to use in the environment in which they were authored. As a result, educators who wish to adopt these approaches are compelled to produce large quantities of high quality educational content. This can lead to excessive workloads being placed upon the educator, whose efforts are better exerted on the pedagogical aspects of eLearning design. The accessibility, portability, repurposing and reuse of digital resources thus became, and remain, major challenges. The key motivation of this research is to enable the utilisation of the vast amounts of accumulated knowledge and educational content accessible via the World Wide Web in Technology Enhanced Learning (TEL). This thesis proposes an innovative approach to the targeted sourcing of open corpus content from the WWW and the resource-level reuse of such content in pedagogically beneficial TEL offerings. The thesis describes the requirements, both educational and technical, for a tool-chain that enables the discovery, classification, harvesting and delivery of content from the WWW, and a novel TEL application which demonstrates the resource-level reuse of open corpus content in the execution of a pedagogically meaningful educational offering. Presented in this work are the theoretical foundations, design and implementation of two applications: the Open Corpus Content Service (OCCS); and the User-driven Content Retrieval, Exploration and Assembly Toolkit for eLearning (U-CREATe). To evaluate and validate this research, a detailed analysis of the different aspects of the research is presented, outlining and addressing the discovery, classification and harvesting of open corpus content from the WWW and open corpus content utilisation in TEL. This analysis provides confidence in the ability of the OCCS to generate collections of highly relevant open corpus content in defined subject areas. The analysis also provides confidence that the resource-level reuse of such content in educational offerings is possible, and that these educational offerings can be pedagogically beneficial to the learner. A novel approach to the sourcing of open corpus educational content for integration and reuse in TEL is the primary contribution to the State of the Art made by this thesis and the research described therein. This approach differs significantly from those used by current TEL systems in the creation of learning offerings and provides a service which is considerably different to that offered by general purpose web search engines. Description: PUBLISHED

2009-01-01T00:00:00Z WOULFE, MUIRIS http://hdl.handle.net/2262/35987 2010-06-03T15:57:25Z 2005-01-01T00:00:00Z

Title: Analogue Dynamics Engine (ADE) Author: WOULFE, MUIRIS Abstract: This report outlines the design and implementation of the Analogue Dynamics Engine (ADE). The ADE is a physics engine constructed from a hybrid, analogue and digital, computer. Software physics engines are becoming increasingly common in computer games, and the ADE was designed as a hardware equivalent to these software engines. Analogue computers, although currently rare, have useful properties such as their ability to evaluate functions in realtime. The physics engine exploits this functionality while using digital components to provide reconfigurability.; The core hybrid computer was constructed by connecting twenty nine custom designed reconfigurable analogue cells to thirty two bus lines, using programmable interconnect. Each cell can perform inversion, integration, addition and multiplication. At the periphery of this computer lie two ADCs and two DACs, so that the hybrid computer may provide a digital interface.; In order to make the engine suitable for use with games, it was decided to make simulations multiplexable, so that multiple simulations could be run “concurrently”. This requires simulations to be executed faster than real-time. Additionally, state must be saved and restored, which was achieved through replicating the capacitors.; Finally, this report analyses the viability of this project for use in computer games. Ultimately, it was determined that an analogue computer could become a viable replacement for the software physics engines in use today. In fact, it offers benefits that cannot be obtained using today’s software physics engines. Description: PUBLISHED

2005-01-01T00:00:00Z KANE, BRIDGET THERESA http://hdl.handle.net/2262/35906 2011-03-09T18:09:41Z 2008-01-01T00:00:00Z

Title: An Analysis of the Dynamics of Multi-Disciplinary Medical Team Meetings and the Use of Communication Technology Author: KANE, BRIDGET THERESA Description: PUBLISHED

2008-01-01T00:00:00Z KEENEY, JOHN http://hdl.handle.net/2262/30726 2010-06-03T15:57:04Z 2004-01-01T00:00:00Z

Title: Completely unanticipated dynamic adaptation of software Author: KEENEY, JOHN Abstract: Dynamic adaptation of software behaviour refers to the act of changing the behaviour of some part of a software system as it executes, without stopping or restarting it. It is difficult to dynamically adapt software if the need for adaptation arises while the software is executing, and especially so if the program is compiled and the source code is unavailable. Ideally, it would be possible for adaptations to be applied to a running application without any anticipation of the adaptation itself, preparation of the location for that adaptation, or even anticipation of the need for some adaptation. Even with the best planning and foresight it is virtually impossible to anticipate at design and production stages all of the dynamic behaviour adaptations that may be required for a piece software, especially if the need for adaptation is triggered by unpredictable and erratic changes in the operating context, the application's resources and demands, and the users’ requirements.; The need for dynamic adaptation arises in various circumstances, from the very simple desire to dynamically customise a piece of software to suit current needs, through to a necessity to continually evolve a long-running program as its requirements and operating context change. These adaptations may simply involve pre- or post-processing of operations, for example, to support consistency checking, through to dynamically adapting the core behaviours of an application as its operating context or requirements change, for example to support dynamic upgrading or repair of the system. While it may be necessary to adapt the core functional behaviours of an application, it may also be necessary to change or insert new non-functional behaviours that do not change what the software does, but rather how it does it. Examples here include dynamically inserting debugging or tracing statements, through to making some object in an application persistent or remotely accessible. To perform these changes it should not be necessary to restart the application, or indeed have access to the source code of the application since the core problem domain being modelled by the application has not changed.; If dynamic adaptation is to be completely unanticipated, the management and control of the adaptation process must also be dynamically adaptable. It is unrealistic to expect an adaptation framework using a hard-coded, static, or inflexible approach to adaptation management, to perform adequately in a generalised manner. Only by decoupling the adaptation mechanism from the adaptation control, and dynamically specifying and adapting the adaptation control strategies, can completely unforeseen dynamic adaptation of running software become a realistic goal. This thesis provides an in depth discussion of unanticipated dynamic adaptation, introduces the term “completely unanticipated dynamic adaptation” to refer to adaptations where all properties of the adaptation can remain unanticipated until during runtime, and identifies the set of requirements that must be met to achieve this. This thesis presents the Chisel adaptation framework, and demonstrates that a generalpurpose, context-aware dynamic adaptation framework is achievable. This system can be used to perform almost any unforeseen behavioural adaptation without stopping the application, and without changing the application itself. In this system a human-readable, dynamically updatable policy script was chosen as the favoured approach to drive the adaptation mechanism in a responsive manner by monitoring changes in the user, application, and environmental context. The Chisel framework also demonstrates that behavioural reflection, using the managed but unforeseen dynamic selection of Iguana/J metatypes, is a valid and powerful technique for completely unanticipated dynamic software adaptation. In addition, the Chisel framework provides a structured mechanism to allow a user to inspect and probe the internal operation of compiled software without access to the software's source code to allow that software to be adapted or extended as appropriate.; To evaluate Chisel and validate our claims, a number of examples and case studies are used, including the use of the Chisel framework to dynamically adapt an off the shelf network application, as it ran, to use ALICE, a middleware for mobile computing environments, and how, using an Iguana/J metatype to implement a snap-on non-functional behaviour to implement a naming mechanism for individual objects, those named objects can be individually adapted or queried as context sources. Description: PUBLISHED

2004-01-01T00:00:00Z Gray, Elizabeth http://hdl.handle.net/2262/24260 2010-06-03T15:56:11Z 2008-11-10T12:27:05Z

Title: A Trust-Based Reputation Management System Author: Gray, Elizabeth Abstract: Since its inception in the early 1990s, e-commerce in consumer-to-consumer (C2C) markets has achieved great success, with significant projected growth. For example, the Internet auction provider, eBay, has established itself as the largest global player in this market, with $34.2 billion worth of merchandise being auctioned in 2004 and 135 million registered users in 32 markets worldwide. The C2C domain, analogous to its conventional physical marketplace equivalent, is built on trust. Buyers send payments to complete strangers from whom they have purchased goods and trust that the goods will be sent in return. Sellers trust buyers to make good on their payments. All users risk loss, both financial and of their time. Users establish reputations about their trustworthiness through an integrated feedback collection and distribution system, i.e., a reputation management system. Thus, an online marketplace approximates its traditional predecessors as a system in which the human concepts of trust, risk, and reputation are critical to performance. The apparent benefits of interacting in such a strongly-networked global market are accompanied by innovative adaptations of traditional hazards. The Internet, while connecting disparate user groups to increase transaction potential and shared knowledge about the marketplace, also permits user anonymity and transactional intangibility, which can lead to fraud, theft, and collusion. Reputation management systems attempt to limit incorrect behaviour and to assist decision making by providing records of feedback about interactions, called recommendations, for each community participant. These systems are not without their own limitations. First, commercial reputation management systems typically promote usability over accurate evidentiary analysis, meaning that data which could be extremely useful to decision-making is disregarded by the evidence collection mechanism so that ease-of-use is maintained for community members when they are voluntarily providing feedback. This first issue leads directly to the second, which is inaccurate evidentiary analysis with regard to contextual relevance in terms of user role, timeliness of evidence, and environmental context. In this regard, trustworthiness is usually linked solely to the overall number of positive recommendations about a user, regardless of the interaction context being considered. Third, the dynamics of user interactions are not addressed, and interaction dynamics in such an evidence-rich environment are difficult, if not impossible, for an average user to manually detect. Without the ability to analyse interaction dynamics, the fourth and fifth issues arise, namely that the analysis of whether or not a user provides useful and accurate recommendations about another user or whether or not a group of users are colluding with malicious intent are both difficult to observe. Sixth, risk is not explicitly calculated by the reputation system, and may not be assessed by the user at all. Seventh, and finally, a reputation is often no more than an overall summary of a collection of thousands of individual recommendations rather than an explicit portrayal of the trust and risk involved in a context-specific interaction.; This thesis describes a trust-based reputation management system (RMS) that addresses each of the above issues. The system resolves the ease-of-use versus accuracy problem by maintaining usability viii but with enhanced collection and analysis of evidence with regard to domain-specific behaviour. Furthermore, the system provides increased accuracy of evidentiary analysis with regard to context by assessing evidence in terms of role, timeliness, and environment. Interaction dynamics are also considered in the system’s decision-making process, thus providing for the ability to limit exposure to risk from unreliable recommendations as well as the ability to assess the likelihood of colluding behaviour. The risk of an interaction resulting in malicious behaviour is explicitly analysed and stated to the user. Finally, the reputation summary is replaced by the explicit assessment of the trust and risk involved in interacting with another user, providing a security decision as advice to a user on whether or not to engage in an interaction. The RMS builds on the work of the SECURE (Secure Environments for Collaboration among Ubiquitous Roaming Entities) project. Grounded on a formal model, the SECURE trust-based decision-making framework applies trust and risk to evidence in a manner comparable to the human decision-making process. We use the SECURE model as a basis with which to design our own application-specific mechanisms for reputation management in Internet auctions, and these mechanisms provide for the observation of domain-specific behaviour such as fraud and theft, assessment of contextual relevance, and analysis of risk in financial terms that is made explicit to the end user. Additionally, in the reputation management for Internet auctions application domain, SECURE is deficient in analysing the dynamic aspects of marketplace networks, and therefore we design additional techniques for interaction management. These techniques underlie an extension to the SECURE framework that includes methods for the weighting of recommendations based on the application of recommendation weighting policy to trustworthy recommendation paths within the graph of marketplace participants; and the identification of colluding behaviour between users within the marketplace community, by assessing interaction dynamics between users over time. Our evaluation of the RMS shows that it reduces complexity, increases accuracy, and maintains usability of reputation management for Internet auction users. It validates that the RMS, in its observation and identification of normal and abnormal domain-specific behaviour, reduces complexity by providing accurate decision-making advice to users. Furthermore, the evaluation confirms that the analysis of context in terms of role, time, and environmental factors can further reduce complexity in the decision-making process while maintaining usability. Additionally, the evaluation demonstrates that recommendation weighting can protect a user against the potential unreliability of recommended evidence. Finally, the evaluation establishes that a reputation management system based on a computational trust-based decision-making model can counter the issues in existing commercial reputation management systems and provide increased benefit to users interacting in the Internet auction domain.

2008-11-10T12:27:05Z Lafferty, Donal http://hdl.handle.net/2262/24259 2010-06-03T15:56:29Z 2008-11-10T12:24:54Z

Title: Aspect-Based Properties Author: Lafferty, Donal Abstract: Component frameworks are said to support contextual composition when crosscutting functionality is bound to component instances by declarative selection of context properties, rather than through direct connections, such as method invocation, or derivation mechanisms, such as inheritance. Using contextual composition, component framework services such as synchronization, security and transaction support are bound to component instances via method interception. Here, the term component instance is an abstraction for whatever unit of interaction is used to access software component functionality be it an interface, an object or a set of objects. The mechanism for declarative selection can range from deployment descriptors, used with EJB Containers, to attribute-based annotations to source, used with CLR contexts of the .NET Framework. Contextual composition frameworks suffer from the lack of tailorability problem as well as the preplanning problem. Contextual composition is employed in a range of component frameworks including MTS contexts, EJB containers, COM+ contexts, CCM containers, and CLR contexts. The lack of tailorability problem arises because the context properties available are either fixed or extensible in an ad hoc manner. The preplanning problem arises because accessing context properties constrains component architecture. Binding to context properties involves exposing component functionality as instance methods and supplying significant prerequisite composition infrastructure. Aspect-oriented programming (AOP) addresses the problems of contextual composition, but AOP solutions are difficult to adopt as they introduce language dependencies and suffer problems with reusability. AOP offers language extensions that provide a linguistic means of implementing new crosscutting concerns encapsulated in aspects. An emphasis on noninvasive binding means AOP places fewer restrictions on component architecture, but relying on language extensions forces components to align to a single language for interoperability. Furthermore, reusability involves the customization of an aspect, which is much more complex than declarative mechanisms used with contextual composition such as attribute-based property selection. This thesis introduces aspect-based properties, which avoid the restrictions of context properties, provide language-independence and simplify reuse. Aspect-based properties are implemented by aspects with pointcut-advice semantics, and composition is the responsibility of the aspect weaver rather than the components being composed. The underlying aspect model is language-independent in that it allows aspects and components to be written in a variety of languages and freely intermixed. Aspect-based properties use attribute-based property selection to allow reuse without the need to customise an aspect. An implementation for standardised Common Language Infrastructure (CLI) demonstrates aspect-based properties to be easy to adopt and to solve the problems identified with context properties. Aspect-based properties are implemented as CLI components with XML-based crosscutting specifications that are composed with application components using a load-time weaver. For reusability, aspect-component bindings are written in terms of attributes types, but for support of legacy components custom crosscutting is available in which bindings are specified in terms of CLI metadata. Language-independence is available in either case, which we demonstrate by weaving aspect-based properties and components written in object-oriented, procedural and functional programming languages. In comparison to the CLR contexts for the CLI, aspect-based properties provide a richer join point model for better tailorability, the weaver allows them to avoid preplanning issues, and they execute an order of magnitude faster.

2008-11-10T12:24:54Z WADE, VINCENT PATRICK http://hdl.handle.net/2262/3558 2010-06-03T15:55:33Z 2006-01-01T00:00:00Z

Title: Designing telecommunication service management systems Author: WADE, VINCENT PATRICK Abstract: In today's telecommunication industry, the management of services is seen as a key enabler and differentiating factor in the flexible delivery of telecommunication solutions. Increased competition and globalisation of markets have created unique pressure on telecommunications service providers to support service oriented, reusable management components which can optimise the provisioning and adaptation of business and systems processes. This thesis proposes a model driven development strategy which provides integrated, but separate support for the development of reusable component designs as well as the flexible development of business process driven systems constructed using these reusable component designs. The thesis specifies two integrated development guidelines which comprise the methodology. The thesis also describes the validation and evaluation of the guidelines in two trials. These trials involve the development of a catalogue of component designs and the development of several different telecommunication management solutions constructed using these component designs. The thesis also provides a comparison of the proposed guidelines with existing telecommunication development processes and mainstream software industry development processes. Description: APPROVED

2006-01-01T00:00:00Z