Discussion Notes

Jan 19

(courtesy Saverio Perugini)

PHOAKS

  • purely collaborative
  • mines URLs
  • role specialization
  • uses IR metrics - precision and recall - acceptable here
  • results verified against FAQs
  • results could be used to create FAQs in domains where they currently do not exist and/or improve upon existing FAQs

Referral Web

  • discovers a `static' social network; entities are assumed to not move stations during the time under consideration
  • lifetime important - in this case it is many years
  • social network modeling can be very fickle; need to know when two entities being referred to in different ways are actually the same and when to give importance to distinctions
  • no weight associated with links
  • only one type of link
  • strong theoretical basis from bibliometrics
  • very error prone
  • Auto-refresh tricks in AltaVista and Excite
  • see fifth reference for one of the first untouted works on recommender systems

Fab

  • a hybrid of both content and collaborative-based filtering
  • content features are orthogonal
  • people's tastes are not necessarily orthogonal - need to mine types, which introduces excess and defect, which is what we recommend on
  • cluster by ratings, not tastes

Siteseer

  • overlap in bookmark folders
  • how do they get the bookmarks?
  • similarity relationship is directed and not necessarily reciprocal - sets Siteseer apart from the other recommender systems in this CACM special issue on recommender systems
  • backflip system allow users to share bookmarks
  • not to be confused with Citeseer

Grouplens

  • clusters users - one way of handling sparsity (another way coming in next class)
  • recommend only within the bucket / cluster
  • author went on to start NetPerceptions - personalization

Rec. Sys. for Evaluating Computer Messages

  • Title doesn't seem to fit
  • Definition of Nash Equilibrium
  • only 2 actions (read or wait) - makes for easy analysis
  • Example sites: epinions.com

Summary

  • mostly collaborative - reflects the fact that this issue was born out of a collaborative filtering workshop
  • no talk of any detailed domain-specific modeling
  • bedside reading, not very technical



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