Computing and Information Systems - Theses
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ItemSeamless proximity sensing( 2013)Smartphones are uniquely positioned to offer a new breed of location and proximity aware applications that can harness the benefits provided by positioning technologies such as GPS, and advancements in radio communication technologies such as Near Field Communication (NFC) and Bluetooth low energy (BLE). The popularity of location aware applications, that make use of technologies such as GPS, Wi-Fi and 3G, has further strained the already frail battery life that current generation smartphones exhibit. This research project is aimed to perform a comparative assessment of NFC, BLE and Classic Bluetooth (BT) for the purpose of establishing proximity awareness in mobile devices. We demonstrate techniques; in the context of a mobile application to provide seamless proximity awareness using the three technologies, with focus on accuracy and operational range. We present the results of our research and experimentation for the purpose of creating a baseline for proximity estimation using the three technologies. We further investigate the viability of using BT as the underlying wireless technology for peer to peer networking on mobile devices and demonstrate techniques that can be applied programmatically for automatic detection of nearby mobile devices.
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ItemDeveloping systems for gene normalisation( 2007-10)The rapid growth of biomedical literature has attracted interest from the text mining community to develop methods to help manage the ever-increasing amounts of data. Initiatives such as the BioCreative challenge (Hirschman et al. 2005b) have created standard corpora and tasks in which to evaluate a variety of systems in a common framework. One such task is gene normalisation, in which the problems of synonymy and polysemy in gene name identification are overcome by mapping each mention back to a unique identifier, unambiguously identifying that gene. This task is one of the foundations required for any kind of text mining system working with biomedical literature, where we must be very certain of which genes are being discussed in the text. (For complete abstract open document)
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ItemContext-sensitive glossing of Japanese webpages( 2007-10)This thesis proposes a method for automatically sense-to-sense aligning dictionaries in different languages (focusing on Japanese and English), based on structural data in the respective dictionaries. The basis of the proposed method is sentence similarity of the sense definition sentences, using a bilingual Japanese-to-English dictionary as a pivot during the alignment process. We experiment with various extensions to the basic method, including term weighting, stemming/lemmatisation, and ontology expansion.
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ItemDynamically detecting and modelling the visitor’s interests in a museum environment( 2007-10)A museum contains a diversity of information sources, from which a visitor can select according to his interests. Although every visitor may have a different purpose for visiting the museum, in our research we assume the motivation for all visits is to get information. However, more often than not, visitors do not obtain a thorough coverage of information on the topics of their interests, given a limited time duration for the tour. To maximise this coverage, the solution is to increase our knowledge of each individual’s information needs, and develop a system to provide personalised and contextually relevant navigation to the visitor. The personalisation component ensures the provided information is adaptive to the interests of each unique visitor, whereas the contextual relevance component looks at the state of the visitor in relation to their surroundings. In this project, we develop a prototype system that aims to address both components; in particular, we experiment with various computational linguistic models on the prototype system and contrast their effectiveness in detecting and modelling the visitor’s interests during the museum tour.
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ItemThe production of meaningful route directions using landmark extraction( 2006-11)In order for automated navigation systems to operate effectively, the route instructions they produce must be clear, concise and easily understood by users. Thequality and coherence of route instructions may be improved via landmark chunking, whereby a turning instruction is given with reference to a nearby landmark. In order to incorporate a landmark within a coherent sentence, it is necessary to first understand how that landmark is conceptualised by travellers — whether it is perceived as point-like, line-like or area-like. This conceptualisation determines which prepositions and verbs are appropriate when referring to the landmark. This thesis investigates the viability of automatically classifying the conceptualisation of landmarks relative to a given city context. First, we construct a web-based annotation interface to solicit gold-standard judgements from expert annotators over a set of landmarks for three major cities (Melbourne, Hamburg and Tokyo). We then experiment with the use of web data to learn the default conceptualisation of those landmarks, analysing their occurrence in a fixed set of lexico-syntactic patterns. Based on this, we develop two automated landmark classifiers and evaluate them against the gold standard annotations,investigating patterns of convergence or divergence in landmark categorisation.
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ItemAnalysis and prediction of user behaviour in a museum environment( 2006)Visitors to a museum enter an environment with a wealth of information. However not all of this information may be located in physical form. It may be accessible through an online web-site and available for download, or this information could be presented by a tour guide that leads you through the museum. Neither of these sources of information allow a visitor to deviate from a set path. If a visitor leaves a guided tour, they will not have access to the resource that is supplying them with the extra information. If they deviate from a downloaded tour, they again will not have the correct information sheets for an exhibit that is not directly on their tour. The solution is to create a Recommender System based on the conceptual similarity of the exhibits. This system creates a dynamic tour through the museum for a given visitor by recommending exhibits that the visitor is interested in. Conceptual similarity of exhibits can be comprised of elements including the physical proximity, the semantic content of the exhibit, and the opinions of previous visitors. By using a combination of these similarities, we have produced a system that recommends relevant exhibits in 51% of test cases.
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ItemAdaptive psychophysical procedures and Ulam's game( 2006-10)The problem of finding the threshold of a psychometric function is of major interest to researchers in the field of psychophysics, and has applications in many areas of medical diagnosis, particularly those dealing with perception, such as optometry and hearing tests. This problem is closely related to other problems in computer science, such as search with errors, however most existing literature does not make this link. This thesis provides a review of existing algorithms for finding the threshold, with an emphasis on identifying the types of problems for which each algorithm is useful. We also address a number of issues which are not adequately covered in the literature. These include choosing an appropriate loss function to evaluate the performance of an algorithm for a given problem, as well as relating the problem of finding the threshold to binary search with errors problems in computer science. Finally, this research presents a new algorithm for finding the threshold of a psychometric function, ENT-FIRST, which results in improved performance compared to many existing algorithms.
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ItemComputational gene finding in the human malaria parasite Plasmodium vivax( 2006-10)Different approaches to genome annotation are reviewed and compared with reference based annotation using GeneMapper in the human malaria parasite Plasmodium vivax. It is found that the latter approach does not achieve sensitivity and specificity as high as those for some ab initio techniques. Potential reasons for this are identified and discussed. As part of the process of using GeneMapper, codon substitution matrices are constructed and examined. This leads to the discovery of evidence from which we derive a conjecture regarding Plasmodium evolution.
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ItemVisualising the impact of changes to precision grammars( 2010)The development of precision grammars is an inherently resource intensive process. In this thesis we investigate approaches for providing grammar engineers with greater feedback on the impact of changes made to grammars. We describe two different visualisations which are created by comparing parser output from two different states of the grammar. The first involves the ranking of features found in parser output according to their magnitude of change so as to provide a low-level picture of the affected parts of the grammar. The second involves performing clustering over sentences whose parsability has changed in an attempt to find related groups of changes and accompanying sentences which exemplify each locus of change. These approaches provide complimentary avenues of feedback which can hopefully improve the efficiency of the grammar engineering development process.
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ItemImpact of user characteristics on online forum classification tasks( 2009)We develop methods for describing users based on their posts to an online discussion forum. These methods build on existing techniques to describe other aspects of online discussions communities, but the application of these techniques to describing users is novel. We demonstrate the utility of our proposed methods by showing that they are superior to existing methods over distinct thread-level, post-level and user-level classification tasks, utilizing real world datasets. In all cases, we attain statistically significant improvements over baseline results. In post-level classification, we also see statistically significant improvements over state-of-the-art benchmark methods. Our major contributions in this work are • creation of a corpus with user-level annotations • detailed description and analysis of three relevant corpora • implementation of a data model for accessing forum data • implementation of feature extraction techniques • evaluation and analysis of user-level features over classification tasks Our work on preparing corpora and providing extensible implementations of feature extraction will be of particular value to researchers looking to work in this field.