Wednesday, May 23, 2007

SemTech conference session notes: migrating from relational world to semantics

Notes from Migrations: Moving From a Relational World to a Semantic One, Barbara McGlamery. Case study: redesign of web site for Entertainment Weekly. Wanted to make more use of data collected, and make more scalable. Category Tool, year 2000, successful but not flexible (very hierarchical categories) and not scalable. Topics - semantic web tool 2005, built on

Category Tool: 78K categories, plus relations, built on Vignette story server. Everything is a category (both classes and instances). Topics: built on Sybase DB. RDF and OWL. More flexible structure, represent individuals and relationships directly in OWL. Goals include to make the data more portable, poly-hierarchy (Will Smith is an actor and a musician), and support multipart relationships.

Ontology design driven by business needs and application, but not re-using existing ontologies. Ontology design issues

  • dates would sometimes be imprecise (May 12 2007 vs. Spring 2007)
  • multipart relationships Critic Owen gave grade B to move M. Used specific properties e.g. :gaveGradeA, :gaveGradeAMinus

Also data clean-up problems. Homonyms, relationships in the wrong direction (film is lead in actor). Done manually by interns using spreadsheets!

Did the migration in three phases, development, QA and complete. Each phase had to correct mistakes or add cleanup, but still very manual. Other sites in Time web presence now also use the same named entities.

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