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Semantic-Based Navigation in Open Spaces 295
10.7.4 /facet: Browser for Heterogeneous Semantic Repositories
/facet (Hildebrand et al., 2006) is a faceted browser for heterogeneous information spaces
consisting of distributed semantic repositories represented in RDFS. It takes advantage of
both the rdfs:subClassOf property and the rdfs:subPropertyOf property in order to process
facet restriction hierarchies.
Furthermore, /facet supports multi-type queries and runtime facet specification thus
greatly increasing flexibility and support for heterogeneous repositories. The multi-type
capability effectively translates into an additional facet, which is used to specify the target
data type. Based on the selection in the type facet, other facets are made available.
Figure 10-22 shows the /facet GUI. The selected type vra:Work corresponds to facets
Creator, Date and Material.Medium. Moreover, /facet supports semantic keyword search,
which allows users to perform keyword-based search on
− all instances (helps find a suitable instance type),
− individual facets (improves movement and restriction selection),
− and across all facets (improves orientation).
Lastly, /facet supports the grouping of search results based on individual properties and
timeline visualization of dates. However, it does not support personalization nor advance
link generation and recommendation techniques.
Figure 10-22. Example of the /facet GUI with multiple facets (top), constrained search results (center)
and timeline display (bottom), taken from (Hildebrand, van Ossenbruggen, & Hardman, 2006).