This dissertation addresses the dichotomy between semantic and episodic knowledge by focusing on the evolution of scientific knowledge. Even timeless scientific knowledge about the nature of the world accrues only through discrete episodes, with each scientist building upon the work of his/her predecessors. Hence, a memory organization to model the knowledge of a scientific field should reflect not only the knowledge pertaining to the field, but also the knowledge pertaining to the evolution of the field. A computer program called RA is described: RA proposes a memory organization for scientific knowledge in terms of a representational idea called Research Schemas. Research Schemas view research papers, not as isolated pieces of text, but as related episodes that contribute to the growth of a scientific discipline. This memory organization is validated by showing that it supports a number of different capabilities: it enables RA to suggest new research directions, acquire new research schemas, retrieve papers that have similar research strategies, and generate both chronological and analogical summaries of research papers. A combination of these capabilities constitutes a framework for 'Computer-Aided Research.' The RA system also includes a learning technique to acquire new research schemas. While similarity-based techniques use multiple examples (and some form of encoded bias) and explanation-based techniques use a domain theory as the basis for generalization, there is no apparent basis for RA's generalization. An analysis of RA's learning strategy shows that the category structure of RA's world provides a basis for its generalization: RA generalizes instantiations into categories that are both associative and discriminative. Interestingly, this turns out to be precisely the property that characterizes basic-level categories that have been studied by psychologists. This dissertation explores the implication of this results to learning and knowledge representation.

Thesis (Ph. D.)--Drexel University, 2007. / Includes abstract and vita. Includes bibliographical references (leaves 196-207).

Thesis (Ph.D.)--Drexel University, 2008. / Includes abstract and vita. Includes bibliographical references (leaves 142-154).

This thesis takes a multidisciplinary approach to understanding the unique abilities of Volunteered Geographic Information (VGI) to enhance the utility of online mashups in ways not achievable with Professional Geographic Information (PGI). The key issues currently limiting the use of successful of VGI are the concern for quality, accuracy and value of the information, as well as the polarisation and bias of views within the user community. This thesis reviews different theoretical approaches in Human Factors, Geography, Information Science and Computer Science to help understand the notion of user judgements relative to VGI within an online environment (Chapter 2). Research methods relevant to a human factors investigation are also discussed (Chapter 3). (Chapter 5) The scoping study established the fundamental insights into the terminology and nature of VGI and PGI, a range of users were engaged through a series of qualitative interviews. This led the development of a framework on VGI (Chapter 4), and comparative description of users in relation to one another through a value framework (Chapter 5). Study Two produced qualitative multi-methods investigation into how users perceive VGI and PGI in use (Chapter 6), demonstrating similarities and the unique ability for VGI to provide utility to consumers. Chapter Seven and Study Three brought insight into the specific abilities for VGI to enhance the user judgement of online information within an information relevance context (Chapter 7 and 8). In understanding the outcomes of these studies, this thesis discusses how users perceive VGI as different from PGI in terms of its benefit to consumers from a user centred design perspective (Chapter 9). In particular, the degree to which user concerns are valid, the limitation of VGI in application and its potential strengths in enriching the user experiences of consumers engaged within an information search. In conclusion, specific contributions and avenues for further work are highlighted (Chapter 10).