Meeting 25 02 2004

Meeting 25 02 2004

Present: Conor, Massa

We spoke about PaoloM's general research plan. We will speak about cocoaBlog tomorrow

Paolo Phd Thesis Proposal

Trust-aware Decentralized Recommender Systems

find it at http://sra.itc.it/people/massa/publications/PhDResearchProposal_PaoloMassa.pdf (29th may 2003)

Trust metrics

CF techniques ask users to rate other users. Trust-aware systems ask users to rate (also) other users. In this way we have direct rating of users about users. We call these trust statements. Many websites use this intuition: orkut.com (in affilialtion with google), epinions.com, amazon.com, allconsuming.net, ryze.com, linkedin.com, flickr.com (find more here: http://socialsoftware.weblogsinc.com/entry/6832739961761474/ and at https://www.quickbase.com/db/9f72vfgx?a=q&qid=1 and at http://typaldos.blogspot.com/2003_09_14_typaldos_archive.html). Potentially we could get the data from all these sites and we could use them.

http://Allconsuming.net is worth checking. It was an inspiration in thinking about the future version of cocoa and moleskiing.it.

Conor, you should try at least one of the previous systems.

FOAF (Friend-of-a-Friend) is an XML format that is starting to become very used. The idea is that you publish on your site and you reuse in every site (instead of every to re-express who your friends are and who you trust in every new site) Read about it at

this article explains clearly FOAF http://www-106.ibm.com/developerworks/xml/library/x-foaf.html

systems using it: http://beta.plink.org/, http://trust.mindswap.org/, http://peopleaggregator.com, http://songbuddy.com. It seems that even livejournal (with 2303731 users!) will export the friend lists of its users in FOAF http://www.livejournal.com/community/ljfoaf/. Other systems are starting to do it too: Typepad.com, Tribe.com, Spoke, Linkedin, Plaxo.

something you can do with FOAF http://www.semaview.com/foafwalk/viewer.html?q=sra.itc.it/people/massa/paolofoaf.rdf http://xml.mfd-consult.dk/foaf/explorer/?foaf=http://sra.itc.it/people/massa/paolofoaf.rdf

cocoaBlog and moleskiing will export friend list in FOAF too.

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Aggregating all the trust statements made by users it is possible to construct a trust network (or social network) (see figure at the top of this page).

Trust metrics are used to predict unknown edges using known edges. the basic intuition is that you can propagate trust.

Trust metrics: Local (they predict a personalized trust value of Bill for every user, so that it can happen the trust metrics infers [trust(A,Bill)=0 and trust(B,Bill)=1]) and Global (they predict the same trust value of Bill for every peer)

CollaborativeFiltering has a number of weaknesses (see my paper "Using Trust in Recommender Systems: an Experimental Analysis" at http://moloko.itc.it/paoloblog/papers/trust2004.pdf ), mainly sparseness and vulnerability to attacks (see Collaborative Recommendation: A Robustness Analysis at http://www.cs.ucd.ie/staff/nick/home/research/download/omahony-acmtit2003.pdf [univ college dublin! do you know them?])

In this paper I show how user similarity can be computer against a very small number of other users. Instead Trust propagation allows to reach much more users. If you know the "six degrees of separation" you can easily believe that on epinions.com for instance in 3 or 4 trust hops you reach most of the users.

Paper I want to write: http://moloko.itc.it/trustmetricswiki/moin.cgi/TrustPapers?action=highlight&value=PaperTrustMetricsSurvey

You may want to check this "Trust metrics survey" http://moloko.itc.it/trustmetricswiki/moin.cgi/PaperTrustMetricsSurvey

you could also want to navigate the wiki starting in http://moloko.itc.it/trustmetricswiki/moin.cgi/FrontPage / don't miss http://moloko.itc.it/trustmetricswiki/moin.cgi/AnalyzedTrustMetrics (where i collect almost all the paper that propose a trust metric) and http://moloko.itc.it/trustmetricswiki/moin.cgi/OnlineSystemsThatCollectTrustInformationFromUsers

Trust related conferences are here http://moloko.itc.it/trustmetricswiki/moin.cgi/TrustRelatedConferences

My Blog: http://moloko.itc.it/paoloblog/

A wiki is a writable website (just click on "edit text" or on the white baloon top right)

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for cocoaBlog:

I need to tell you something about Bookmarklets too. remind me this!

See (very interesting) Music related sites at http://moloko.itc.it/cocoacodingwiki/moin.cgi/MusicRelatedSites

Since we spoke of personalize search, check http://eurekster.com (you can express your web of trust (wot)) and see what your trusted friends have searched and clicked)

Something missing? you can add it by clicking on "edit text" (below)