Many real world AI applications involve reasoning on both continuous and discrete variables, while requiring some level of symbolic reasoning that can provide guarantees on the system's behaviour. Unfortunately, most of the existing probabilistic models do not efficiently support hard constraints or they are limited to purely discrete or continuous scenarios. Weighted Model Integration (WMI) is a recent and general formalism that enables probabilistic modeling and inference in hybrid structured domains. A difference of WMI-based inference algorithms with respect to most alternatives is that probabilities are computed inside a structured support involving both logical and algebraic relationships between variables. While some progress has been made in the last years and the topic is increasingly gaining interest from the community, research in this area is at an early stage. These aspects motivate the study of hybrid and symbolic probabilistic models and the development of scalable inference procedures and effective learning algorithms in these domains. This PhD Thesis embodies my effort in studying scalable reasoning and learning techniques in the context of WMI.

This study investigates the dynamics of theory and practice in the design of instructional systems, learning events and learning environments, with a view to synthesizing an integrated metamodel as a framework to facilitate effective learning in systems which use computer technology as a tutor, tool, or environment. This framework can be used as a design aid by instructional designers and instructor-designers, or as a tool to examine existing learning events from the viewpoint of learning and instructional-design theory. The research contributes to inquiry into learning theory by an in-depth study of the elements of the framework itself, investigating how they function in different contexts and contents. Following an extensive literature survey, the researcher synthesizes a concise integrated framework of learning theories and instructional design practice from the cognitive family. This framework, the Hexa-C Metamodel (HCMm), is generated by a process of criterion-based textual filtration through effectiveness criteria, and encompasses the theoretical concepts of constructivism, cognitive learning and knowledge/skills components as well as the practical characteristics of creativity, customization and collaborative learning. Using mainly qualitative ethnographic methods within the contexts of action research and development research, case studies are undertaken, applying the elements of the HCMm as an inquiry toolset to investigate three diverse learning events to determine what they reveal about the practice of effective and motivational learning. The learning events - a computer-based practice environment, an Internet-based course, and a fieldwork project - were selected due to the researcher's close involvement with each intervention. Information from the evaluations of the learning events is then used to further examine in-depth the theories and characteristics which comprise the tool, as well as their interrelationships and ways of implementing them in domains that differ in context and content - distinguishing particularly between well-structured and ill-structured domains. / Dissertation (PhD)--University of Pretoria, 2004. / Curriculum Studies / PhD / Unrestricted

Im Rahmen eines Dissertationsvorhabens am Albrecht Daniel Thaer-Institut für Agrar- und Gartenbauwissenschaften der Humboldt-Universität zu Berlin wurde die „Entwicklung beruflicher Handlungskompetenz in der gärtnerischen Berufsausbildung durch die Anwendung des Lernfeldkonzepts“ untersucht und in einem pädagogischen Unterrichtsexperiment an gartenbaulichen Berufsschulen in sechs Bundesländern durchgeführt. Damit eine durchgängige Kompetenz- und Outcome-Orientierung Berücksichtigung finden kann, erweiterte der Autor die Untersuchung zur Kompetenzentwicklung um die Aspekte Kompetenzmessung und Kompetenzbewertung. Basierend auf einer Arbeitsprozessanalyse zum Ausbildungsberuf Gärtner der Fachrichtung Garten- und Landschaftsbau wurden im Dialog mit dem Berufsstand Kriterien und Indikatoren beruflicher Handlungskompetenz von Landschaftsgärtnern definiert sowie berufliche Handlungsfelder (Tätigkeitsfelder) gebildet, aus denen Lernfelder abgeleitet und ein lernfeldstrukturierten Rahmenlehrplan für den berufsbezogenen Unterricht der Berufsschule konzipiert werden konnte. So war es möglich, handlungs- und kompetenzorientierte Lernaufgaben für den Berufsschulunterricht zu entwickeln, die sich an berufstypischen Arbeitssituationen orientieren. Durch die Bearbeitung dieser Lernaufgaben wurden bei den Versuchspersonen didaktisch begründete Lernhandlungen ausgelöst und angestrebte Kompetenzen entwickelt, die mittels eines standardisierten Bewertungsbogens durch Beobachtung (Fremdeinschätzung) und Befragung (Selbsteinschätzung) gemessen werden konnten. Die Bewertung ausgeprägter Kompetenzen erfolgte durch den Einsatz eines outcome-orientierten Abschlusstests „Virtuelle Kleinbaustelle“. Diese schriftliche Mehrfach-Situations-Aufgabe wurde nach Maßgabe eines systematischen Bewertungsrahmens unter Berücksichtigung der Anschlussfähigkeit an DQR und EQR ausgewertet, sodass auf den Erwerb beruflicher Handlungskompetenz in der Ausbildung zum Landschaftsgärtner geschlossen werden kann. / Within a PhD project at the Albrecht Daniel Thaer-Institute for Agricultural and Horticultural Sciences at Humboldt-Universität zu Berlin the “development of vocational action competencies regarding the training of gardeners based on the application of the concept of domains of learning” was studied in a teaching experiment at six horticultural vocational schools in six German states. To allow for a consistent focus on competencies and outcome, aspects of competencies measurement and competencies evaluation were included in the study of competency development. Based on an analysis of work processes in occupational training of landscape gardeners, criteria and indicators of vocational action competencies in this field were defined in collaboration with the gardening profession; furthermore, vocational fields of activities were developed. On their basis “domains of learning” (“Lernfelder”) could be derived and accordingly a framework curriculum could be developed for vocational lessons at vocational schools. In this manner it was possible to develop activity- and competence oriented learning tasks for lessons at vocational schools. These learning tasks focus on typical work situations in landscape gardening. When the test persons performed these learning tasks, didactically meaningful learning activities were initiated and the test persons developed the desired competencies. These competencies were measured by means of a standardized evaluation form by observation (external evaluation) and questioning (self-evaluation). The evaluation of profound competencies was carried out using an outcome-oriented final examination tool “small virtual building site”. This written multi-situation task was evaluated according to a systematic evaluation frame under consideration of compatibility with GQF and EQF, so that conclusions can be drawn regarding the acquisition of vocational action competencies during the training for landscape gardener.