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The Benefit of Using Tag-Based Profiles. Claudiu Firan, Wolfgang Nejdl, Raluca Paiu 5 th Latin American Web Congress, 2007. Music Recommendation. Personal Music. Community Data. Challenges. New Approach. Personal Music. Personal Tags. Community Data. Why Use Tags?. Tags are:
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The Benefit of Using Tag-Based Profiles Claudiu Firan, Wolfgang Nejdl, Raluca Paiu 5th Latin American Web Congress, 2007
Music Recommendation PersonalMusic CommunityData
New Approach PersonalMusic PersonalTags CommunityData
Why Use Tags? • Tags are: • Written chaotically • Not verified • Unstructured • Heterogeneous • Unreliable • But if many, the correct ones arise • “Wisdom of the masses”
Last.fm – “The Social Music Revolution” Track Similar Tracks Track Usage Info Tags(with weight) Artist Similar Artists User Comments Albums
User Profiles • weight=preference(user,item)
Track-based Profiles (TR) <tracki, weighti> … • preference(user,track) = • log(user_track_#listened) TR
Track-Tag-based Profiles (TT) <tagi, weighti> … • preference(user,tag) = • log( Σi( • log(user_tracki_#listened) ∙ • log(user_tag_tracki_#tagged))) • [∙ ITF(tag)] • ITF = Inverse Tag Frequency • With: TTI • Without: TTN TTI TTN
Tag-based Profiles (TG) <tagi, weighti> … • preference(user,tag) = • log(user_tag_#used) TG
User Profiles from Personal MP3s • Read personal playlist from PC • Match MP3s against our database • Add overall average usage information values
Track- & Tag-based Recommendations Collaborative Filtering <tracki, weighti> … <tagi, weighti> …
Tag-based Search <tagi, weighti> …
Last.fm Crawled Data • 317,058 tracks • 21,177 tags (most prominent ones are music genres) • 289,654 users 12,193 listened at least 50 tracks and used at least 10 tags
Experimental Setup • Create user profiles • 18 subjects • 658 tracks on average in user profile (not statistically significant in influencing algorithm outcome) • Run algorithms • 7 algorithms • 10 recommended items per algorithm per user • Two scores • Quality of recommendation [0-2] NDCG • Novelty of recommendation [0-2] Average
Results • STG: • Lower popularity • Higher quality CFTR: Baseline • NDCG – Novelty: • High inverse correlation • Pearson c = -0.987 • STTI & STTN: • Huge improvement • Statistically significant
Conclusions • CF on tag-based profiles worse than CF on track-based profiles • Search with tags improved recommendation performance substantially • 44% increase in quality • Instant results – virtually no time delay • No cold start problem • Tag-based profiles work also with less rich music repositories • Results probably influenced by the consistent tag usage on Last.fm: mostly genres