PhDWeb directories are hierarchically organised website collections that offer users subjectbased
access to the Web. They played a significant part in navigating the Web in the past
but their role has been weakened in recent years due to their cumbersome expanding
collections. This thesis presents a unified framework combining the advantages of
personalisation and redefined directory search for improving the usability of Web
directories.
The thesis begins with an examination of classification schemes that identifies the
rigidity of hierarchical classifications and their suitability for Web directories in contrast
to faceted classifications. This leads on to an Ontological Sketch Modelling (OSM) case
study which identifies the misfits affecting user navigation in Web directories from
known rigidity issues. The thesis continues with a review of personalisation techniques
and a discussion of the user search model of Web directories following the suggested
directions of improvement from the case study. A proposed user-centred framework to
improve the usability of Web directories which consists of an individual content-based
personalisation model and a redefined search model is then implemented as D-Persona
and D-Search respectively. The remainder of the thesis is concerned with a usability test
of D-Persona and D-Search aimed at discovering the efficiency, effectiveness and user
satisfaction of the solution. This involves an experimental design, test results and
discussions for the comparative user study.
This thesis extracts a formal definition of the rigidity of hierarchies from their
characteristics and justifies why hierarchies are still better suited than facets in
organising Web directories. Second, it identifies misfits causing poor usability in Web
directories based on the discovered rigidity of hierarchies. Third, it proposes a solution
to tackle the misfits and improve the usability of Web directories which has been
experimentally proved to be successful
