Light-weight ontologies for scrutable user modelling

This thesis is concerned with the ways light-weight ontologies can support scrutability for large user models and the user modelling process. It explores the role that light-weight ontologies can play, and how they can be exploited, for the purpose of creating and maintaining large, scrutable user models consisting of hundreds of components. We address problems in four key areas: ontology creation, metadata annotation, creation and maintenance of large user models, and user model visualisation, with a goal to provide a simple and adaptable approach that maintains scrutability. Each of these key areas presents a number of challenges that we address. Our solution is the development of a toolkit, LOSUM, which consists of a number of tools to support the user modelling process. It incorporates light-weight ontologies to fulfill a number of roles: aiding in metadata creation, providing structure for large user model visualisation, and as a means to reason across granularities in the user model. In conjunction with this, LOSUM also features a novel visualisation tool, SIV, which performs a dual role of ontology and user model visualisation, supporting the process of ontology creation, metadata annotation, and user model visualisation. We evaluated our approach at each stage with small user studies, and conducted a large scale integrative evaluation of these approaches together in an authentic learning context with 114 students, of whom 77 had exposure to their learner models through SIV. The results showed that students could use the interface and understand the process of user model construction. The flexibility and adaptability of the toolkit has also been demonstrated in its deployment in several other application areas

MOOClm: Learner Modelling for MOOCs

Massively Open Online Learning systems, or MOOCs, generate enormous quantities of learning data. Analysis of this data has considerable potential benefits for learners, educators, teaching administrators and educational researchers. How to realise this potential is still an open question. This thesis explores use of such data to create a rich Open Learner Model (OLM). The OLM is designed to take account of the restrictions and goals of lifelong learner model usage. Towards this end, we structure the learner model around a standard curriculum-based ontology. Since such a learner model may be very large, we integrate a visualisation based on a highly scalable circular treemap representation. The visualisation allows the student to either drill down further into increasingly detailed views of the learner model, or filter the model down to a smaller, selected subset. We introduce the notion of a set of Reference learner models, such as an ideal student, a typical student, or a selected set of learning objectives within the curriculum. Introducing these provides a foundation for a learner to make a meaningful evaluation of their own model by comparing against a reference model. To validate the work, we created MOOClm to implement this framework, then used this in the context of a Small Private Online Course (SPOC) run at the University of Sydney. We also report a qualitative usability study to gain insights into the ways a learner can make use of the OLM. Our contribution is the design and validation of MOOClm, a framework that harnesses MOOC data to create a learner model with an OLM interface for student and educator usage

Ontology-Based Open-Corpus Personalization for E-Learning

Conventional closed-corpus adaptive information systems control limited sets of documents in predefined domains and cannot provide access to the external content. Such restrictions contradict the requirements of today, when most of the information systems are implemented in the open document space of the World Wide Web and are expected to operate on the open-corpus content. In order to provide personalized access to open-corpus documents, an adaptive system should be able to maintain modeling of new documents in terms of domain knowledge automatically and dynamically. This dissertation explores the problem of open-corpus personalization and semantic modeling of open-corpus content in the context of e-Learning. Information on the World Wide Web is not without structure. Many collections of online instructional material (tutorials, electronic books, digital libraries, etc.) have been provided with implicit knowledge models encoded in form of tables of content, indexes, headers of chapters, links between pages, and different styles of text fragments. The main dissertation approach tries to leverage this layer of hidden semantics by extracting and representing it as coarse-grained models of content collections. A central domain ontology is used to maintain overlay modeling of students’ knowledge and serves as a reference point for multiple collections of external instructional material. In order to establish the link between the ontology and the open-corpus content models a special ontology mapping algorithm has been developed. The proposed approach has been applied in the Ontology-based Open-corpus Personalization Service that recommends and adaptively annotates online reading material. The domain of Java programming has been chosen for the proof-of-concept implementation. A controlled experiment has been organized to evaluate the developed adaptive system and the proposed approach overall. The results of the evaluation have demonstrated several significant learning effects of the implemented open-corpus personalization. The analysis of log-based data has also shown that the open-corpus version of the system is capable of providing personalization of similar quality to the close-corpus one. Such results indicate that the proposed approach successfully supports open-corpus personalization for e-Learning. Further research is required to verify if the approach remains effective in other subject domains and with other types of instructional content

Supporting students’ confidence judgement through visualising alignment in open learner models

Supporting students’ knowledge monitoring skills, a component of metacognition, can help students regulate their own learning. This thesis investigates the alignment of learners’ confidence in their knowledge with a computer’s assessment of their knowledge, visualised using an Open Learner Model (OLM). The research explored students’ preferred method for visualising inconsistent data (e.g. misalignment) in an OLM, and the ways in which visualising alignment can influence student interaction with the computer. The thesis demonstrates that visualising alignment in Open Learner Models signifi-cantly increases students’ confidence compared to a control condition. In particular, visualising alignment benefited low-achieving students, in terms of knowledge monitoring and this was associated with improvements in their performance. Students showed a preference towards the visualisations that provides an overview of the in-formation (i.e. opacity) rather than ones, which provide detailed information. Graph-ical representation is shown to be more beneficial in motivating students to interact with the system than text-based representation of the same information in the con-text of representing the alignment within OLMs

Learners' self-assessment and metacognition when using an open learner model with drill down

Metacognition is ‘thinking on thinking’. It is important to educational practices for learners/teachers, and in activities such as formative-assessment and self-directed learning. The ability to perform metacognition is not innate and requires fostering, and self-assessment contributes to this. Literature suggests proven practices for promoting metacognitive opportunities and ongoing enquiry about how technology best supports these. This thesis considers an open learner model (OLM) with a drill-down approach as a method to investigate support for metacognition and self-assessment. Measuring aspects of metacognition without unduly influencing it is challenging. Direct measures (e.g. learners ‘thinking-aloud’) could distort/disrupt/encourage/effect metacognition. The thesis develops methods to evaluate aspects of metacognition without directly affecting it, relevant to future learning-analytics research/OLM design. It proposes a technology specification/implementation for supporting metacognition research and highlights the relevance of using a drill-down approach. Using measures that correspond to post-hoc learner accounts, this thesis identifies a baseline of student activity that is consistent with important regulation of cognition tasks and students’ specific interest in problems. Whilst this does not always influence self-assessment accuracy, students indicating their self-assessment ability can be used as a proxy measure to identify those who will improve. Evidence supports claims that OLMs remain relevant in metacognition research

Ein Beispiel der späteisenzeitlichen Orlea-Maglavit Fibel aus der Imre Pongrácz Sammlung

Imre Pongrácz (1849-1903) war Major bei der Honvèd Infanetrie und Militärkommandant des Orșova Hafens. Während seines Lebens sammelte er über 6000 Antiquitäten, die überwiegend vom rechten Donau-Ufer, aus heutigem Serbien, stammen und von den sog. “Schatzjägern” gesammelt wurden. Immerhin fehlt für die meisten Objekte aus der Sammlung eine Fundplatzbestimmung. Ein bedeutender Bestandteil der Sammlung schließt unterschiedliche Fibeln mit ein, darunter auch etwa achtzig späteisenzeitlicher Fibeln. Die hier präsentierte Fibel gehört dem sog. “Orlea-Maglavit” Typ, der während der Späteisenzeit in Gebieten um die Donau auf dem Balkan vertreten war. Obwohl einige “Orlea-Maglavit” Fibeln schon veröffentlicht sind, werden im hiesigen Text einige Aspekte (Tragweise, Geschlechtsbestimmung der Fibelträger usw.) angesprochen, die bisher ungeklärt blieben

Coins from Thracian and Lower Moesian Mints from the Viminacium Necroplis of Pećine

During the extensive archaeological rescue excavations of the southern necropoles at Viminacium, at one of them, Pećine, 17 coins were found from provincial issues of Thracian mints, issued by eight mints, and two pieces from Moesia Inferior, originating from one mint. Out of a total of 19 pieces, 11 were found in graves, and the others in the layers of the necropoli