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Assessing the Value of Contributions in Tagging Systems

Assessing the Value of Contributions in Tagging Systems. Elizeu Santos- Neto , Flavio Figueiredo Jussara Almeida, Miranda Mowbray Marcos Gon çalves, Matei Ripeanu. The 2 nd IEEE SocialCom /SIN -- August 2010. Commons-based Peer Production Systems.

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Assessing the Value of Contributions in Tagging Systems

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  1. Assessing the Value of Contributions in Tagging Systems Elizeu Santos-Neto,FlavioFigueiredo Jussara Almeida, Miranda Mowbray Marcos Gonçalves, Matei Ripeanu The 2nd IEEE SocialCom/SIN -- August 2010

  2. Commons-based Peer Production Systems Decentralized, Collaborative & Non-proprietary [1] Offline Online Car pooling Volunteer Firefighters InformationSharing ResourceSharing Wikis BitTorrent Tagging SETI@Home Q&APortals OurGrid.org [1] Y. Benkler. “The Wealth of Networks”. Yale University Press (2006).

  3. Online Peer Production Systems • Annotation = Tags + Items • Tags are free-form words • Items can be virtually anything • URLs, photos, videos, citation records, etc… Expertise CPU Bandwidth Time Annotations Photos Tagging Systems

  4. Why is it important to study tagging systems? • Increasingly popular • Millions of users [2] • GBytes of content and annotations daily [2] • User-generated metadata = new opportunities • To improve existing systems (e.g., social search) • To create new mechanisms (e.g., reputation systems) • Open problem: how to quantify the value of user contributions in these systems? [2] R. Ramakrishnan, A. Tomkins. “Toward a PeopleWeb”. IEEE Computer 40(8): 63-72 (2007)

  5. Long Term Goal To define a method that quantifies the value of users’ contribution in tagging systems that is accurate,feasible and robust. What is the tolerance to malicious users? What is the computational complexity? How close is it to the true value of user contribution?

  6. Where Are We? (Contributions to Date) • Problem formalization • A solution framework • A method to quantify the value of tags • Entropy-based metric • Algorithms to compute the metric

  7. Solution Framework

  8. Value of User Contributions inTagging Systems • Contribution = Tags + Items • Value of tags • Context: navigation/search • Intuition: value ≈ improvement on navigation/search • Value of an item • Context: item usage • Intuition: value ≈ usefulness to a user Annotations Content

  9. The Value of User ContributionInformation flow Relevant Item Set Finder Tag Value Calculator Tag Value Aggregator Items Values Information Needs Tags • Info Seeker • Info Producer • Contribution Value Past activity Items Item Usage Monitor Item Value Calculator Item Value Aggregator Usage Values

  10. Value of Tags

  11. Value of Tags • Intuition: tags are valuable if they narrow the scope of navigation, while retrieving relevant items. Items in the system Items retrieved by a set of tags Relevant items to an info seeker Tags published by an info producer Value of tags is proportional to this intersection

  12. Evaluation Criteria

  13. Evaluation Criteria • Feasibility: is the method efficient? • Accuracy: is the estimation close to the real value? • Robustness: can users boost their contributions maliciously?

  14. Preliminary ResultsFeasibility – Part 1 Only 4% of users have more than 100 unique tag assignments.

  15. Preliminary ResultsFeasibility – Part 2 80% of users have NOT produced tags/items in 1 moth or more.

  16. Conclusions & Future Work

  17. Conclusions • Assessing the value of user contributions in social tagging systems is a relevant and challenging problem • This work … • …proposes a solution framework • …provides preliminary results on feasibility • Current efforts… • Evaluating techniques that estimate relevant items • Designing algorithms to calculate and aggregate value

  18. Future Work • Algorithms • Exploit user activity similarity • Aggregation method that exploits implicit social relations • Evaluation • Accuracy – does the estimated value match a ground truth? • Robustness – what about spammers? • Value of items • Build mechanisms that harness the value of contributions • Spam detection • Social search

  19. Assessing the Value of Contributions in Tagging Systems Comments? Questions? elizeus@ece.ubc.ca http://www.ece.ubc.ca/~elizeus

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