Computing and Information Systems - Theses
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ItemInterest-based negotiation in multi-agent systems( 2004)Software systems involving autonomous interacting software entities (or agents) present new challenges in computer science and software engineering. A particularly challenging problem is the engineering of various forms of interaction among agents. Interaction may be aimed at enabling agents to coordinate their activities, cooperate to reach common objectives, or exchange resources to better achieve their individual objectives. This thesis is concerned with negotiation: a process through which multiple self-interested agents can reach agreement over the exchange of scarce resources. In particular, I focus on settings where agents have limited or uncertain information, precluding them from making optimal individual decisions. I demonstrate that this form of bounded-rationality may lead agents to sub-optimal negotiation agreements. I argue that rational dialogue based on the exchange of arguments can enable agents to overcome this problem. Since agents make decisions based on particular underlying reasons, namely their interests, beliefs and planning knowledge, then rational dialogue over these reasons can enable agents to refine their individual decisions and consequently reach better agreements. I refer to this form of interaction as “interested-based negotiation.” (For complete abstract open document)
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ItemAgent-based 3d visual tracking( 2000-07)We describe our overall approach to building robot vision systems, and the conceptual systems architecture as a network of agents, which run in parallel, and cooperate to achieve the system’s goals. We present the current state of the 3D Feature-Based Tracker, a robot vision system for tracking and segmenting the 3D motion of objects using image input from a calibrated stereo pair of video cameras. The system runs in a multi-level cycle of prediction and verification or correction. The currently modelled 3D positions and velocities of the feature points are extrapolated a short time into the future to yield predictions of 3D position. These 3D predictions are projected into the two stereo views, and are used to guide a fast and highly focused visual search for the feature points. The image positions at which the features are re-acquired are back-projected in 3D space in order to update the 3D positions and velocities. At a higher level, features are dynamically grouped into clusters with common 3D motion. Predictions from the cluster level can be fed to the lower level to correct errors in the point-wise tracking.
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ItemOrganization-oriented systems: theory and practice( 1999-02)We investigate the problem of developing a formal language for specifying and reasoning about real-time embedded distributed computer systems. In particular we investigate the problem of developing a theoretical framework for specifying and analyzing different aspects of real-time embedded distributed coordination. In addition to the theoretical framework we also consider the practical aspects of developing real-time embedded distributed systems. (For complete abstract open document)
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ItemAn investigation of interactivity and flow: student behaviour during online instruction( 2004-12)This thesis combines ideas from human-computer interaction, education and psychology to explore the interactions of students in an online learning environment. The motivation for the work was to understand better how to engage students in a highly enjoyable experience of online learning. The thesis describes three experiments. The first experiment was an exploratory study investigating the influence of learner interactions in an online physics learning task. Students worked through an online learning experience that offered high and low levels of interactivity. The aim was to explore their interactions and choices in an environment in which they could elect to move from the highly interactive mode to the less interactive mode at any time. Web logs were used to track their interactions and question probes gathered data on their emotions, learning goals and strategies. The analysis revealed a number of different patterns of interaction. Statistical analysis showed that most, but not all, preferred to follow an interactive path through the material. Students who used the interactive materials showed improved learning gains in transfer-style questions compared to those in the less interactive mode. Several issues were identified as important to consider in a follow-up study: emotions, affect, challenge, and the degree of control that the learner perceives.
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ItemBrowsing and searching compressed documents( 2003-12)Compression and information retrieval are two areas of document management that exist separately due to the conflicting methods of achieving their goals. This research examines a mechanism which provides lossless compression and phrase-based browsing and searching of large document collections. The framework for the investigation is an existing off-line dictionary-based compression algorithm. (For complete abstract open document)
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ItemEfficient mining of interesting emerging patterns and their effective use in classification( 2004-07)Knowledge Discovery in Databases (KDD), or Data Mining is used to discover interesting or useful patterns and relationships in data, with an emphasis on large volume of observational databases. Among many other types of information (knowledge) that can be discovered in data, patterns that are expressed in terms of features are popular because they can be understood and used directly by people. The recently proposed Emerging Pattern (EP) is one type of such knowledge patterns. Emerging Patterns are sets of items (conjunctions of attribute values) whose frequency change significantly from one dataset to another. They are useful as a means of discovering distinctions inherently present amongst a collection of datasets and have been shown to be a powerful method for constructing accurate classifiers. (For complete abstract open document)
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ItemManaged DC power reticulation systems( 1999-11)Electric power engineering, as it applies to low-voltage power reticulation in buildings and industrial sites, is ripe for a ‘paradigm shift’ to bring it properly into the Electronic Age. The conventional alternating-current approach, now over a hundred years old, is increasingly unsatisfactory from the point of view of plant and appliance requirements. Alternative approaches can deliver substantial cost savings, higher efficiencies, power quality improvements, and greater safety. Power reticulation systems in the future can be expected to differ from present systems in two key respects. The first is a greatly increased role for direct current; the second is the augmentation of the power system with a wide range of ‘management’ technologies. Combining these two trends, which can already be observed today, leads to consideration of ‘managed DC’ power reticulation systems, operating from AC bulk supply mains via AC-DC converters.
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ItemChoosing an auditor : corporate governance, interpersonal associations and investor confidence( 2000-06)This thesis provides evidence enabling an analysis of systemic director-auditor links, their nature, their determinants, their association with audit quality as an important component of corporate governance, and investor confidence in companies displaying these links. The motivation for examining interpersonal associations between directors and auditors comes from several sources. First is the observation that auditing is a knowledge-based service the quality of which is difficult to evaluate even after the product has been experienced, adding to the complexity of the purchasing decision (Murray 1991). The use of personal contacts to scan the business environment, disseminate information and reduce uncertainty is likely to assist that evaluation and so aid in auditor selection. One manifestation of these personal contacts is directors who hold directorships on more than one board, creating networks of ties between companies known as interlocking directorates. It tends to be non-executive or external directors who create these ties because they have more time to devote to multiple directorships. Interlocking directorates are a long-standing phenomenon that has been examined in the economics, organisational behaviour and sociology literatures and are argued to engender trust, and mediate transactions. Some countries restrict such directorate ties between industry competitors because of their potential to encourage collusion and competitive disadvantage but Australia has no such restrictions. In order to promote practice growth and firm survival, public accounting firms are known to tap into these networks, which often include former employees, encouraging personal contacts with, amongst others, directors of clients and potential clients. In this way, it is argued, companies interlocked through common directors tend to be audited by a common audit firm with the links extending to even audit partners. Extensive analysis of these interlocking directorates supports these arguments and finds that the association between interlocking directorates and director-auditor links becomes stronger as intra-industry and within confined geographical region data partitioning occurs and varies across audit firms. This variation across firms is subsequently used to model with some success auditor choice - even within the Big 6. Systematic ties between directors and audit firms and/or audit partners potentially threaten at least the appearance of auditor independence, if not the fact. On the other hand, following the DeAngelo (1981)auditor size argument, the potential loss of a ‘family’ of clients associated with a single director if audit quality is degraded may actually enhance audit quality. This thesis argues that directors value personal contact in auditor-client relationships but are aware of the potentially damaging connotations arising from such interpersonal associations and the potential for investor disquiet about them. Implicit in this argument is an assumption that investors are both interested and active in matters of corporate governance, including the audit as a component of corporate governance. As such, the formation of director-auditor links is argued to be contingent on the balance of power between directors and shareholders and the strength of other aspects of corporate governance beside the audit function. Empirical results support this hypothesis only for interlocking created between two or more directors of companies in the same industry. Evidence of director-auditor link association with audit quality is then sought by analysing qualifications and discretionary accruals in the presence of these links. Although alternative explanations are possible, some evidence is found of reduced audit quality. However, using the frequency with which an investor chooses to invest across companies audited by the same auditor as a measure of investor confidence in that auditor, results show that audit quality attributes are valued by investors and that director-auditor links are not associated negatively with investor confidence. Additional tests that examine the association between director-auditor links and various measures of organisational performance find little evidence of negative connotations. Public policy implications flow from the findings and these are discussed together with limitations and ideas for future research.
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ItemInnovation in university computer-facilitated learning systems: product, workplace experience and the organisation( 2003-06)This thesis reports on the development of a generic online system to support learning and teaching at the University of Melbourne. New online technologies, the fostering of innovation at national and university levels and my position within a central educational unit provided the opportunity in 1996 to adapt a previous software package for online use. My observations of the problematic nature of computer-facilitated learning (CFL) production led me to take an open approach to the development, seeking both a practical product and enhanced understanding. A series of formative questions defined the scope and goals of the study, which were to: *produce a generic online learning system; *increase understanding of the workplace experience of that development; and *develop an organisational model for the further development of generic CFL systems. Given this multi-disciplinary focus, many paradigms in the literature could potentially have guided the study. A number of these aligning with the research purposes, context and constructivist philosophy of the study, were reviewed from the perspectives of learning, CFL development and the organisation.
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ItemCustom as a source of supranational internet commerce law( 2003)The Internet has changed the world. Its impact on the global society has been enormous, redefining almost every aspect of our life. It has also added a new quality to traditional commerce that in many instances has drastically transformed the way companies and individuals trade. However, electronic commerce is not a legally safe environment, as there exists a regulatory gap that introduces uncertainty surrounding rights and obligations in cyberspace. This may result in unexpected outcomes for e-commerce participants involved in litigation.