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Inter-Context Trust Bootstrapping for Mobile Content Sharing (daniele quercia) (stephen hailes & licia capra) U C LU C L
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What do I do?
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Research @
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what I research?
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Reputation Systems for Mobiles
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What’s that?
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Example: antique markets
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Problem: Visitors cannot see prices of everything!
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Solution: Sellers disseminate e-ads, and visitors collect them
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Problem: Sellers may disseminate irrelevant ads
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Proposal:
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They may keep track of which sellers send irrelevant ads
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Daniele Quercia Trust model on A: how A decides whether to rely on B to visit a stall
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Daniele Quercia To decide whether to rely on B, A has to set its initial trust in B
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Daniele Quercia 3 Existing Solutions
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Daniele Quercia 1. Fixed values ( over-simplified)
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Daniele Quercia 2. Recommendations ( fake ones)
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Daniele Quercia 3. Similar contexts ( universal ontology)
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Daniele Quercia Two cases: B is 1. unknown 2. partly known
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Daniele Quercia 1. B is unknown
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Daniele Quercia Popular way: Trust propagation (transitivity) ? AB C
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Daniele Quercia Meant for the Web & Proved on “binary” ratings
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Daniele Quercia Algorithm rating unrated trust relationships (needed) 1 ? AB C 2 12 ? unrated nodes (chosen) ABAB ACACCBCB
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? Idea: 1. Similar nodes together 2. Find function: same ratings for rated nodes similar ratings for neighbours
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Daniele Quercia Tested on real data (Advogato: > 55K user ratings)
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Daniele Quercia 2. B is partly known
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Daniele Quercia Popular way: Inter-context Lifting Greek Coins Roman Coins CoinsChairs Antiques
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Daniele Quercia Idea: Users … > Don’t share ontology > Extract “features” from their own ratings
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Daniele Quercia Idea: Users … > Don’t share ontology > Extract “features” from their own ratings
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Daniele Quercia How to extract?
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Daniele Quercia S ingular V alue D ecomposition
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Daniele Quercia Beauty: features not user-specified BUT learnt
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Daniele Quercia Tested on simulation with real parameters
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Daniele Quercia Tested on Nokia 3230 Max: 3.2 ms !
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Daniele Quercia What I’ve told you is on “mobblog UCL” (google it) under tag: “bootstrapping”
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Daniele Quercia
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And User Privacy?
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Daniele Quercia Private filtering (Google for “mobblog private filtering”)
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Daniele Quercia And Resource Discovery?
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Daniele Quercia Folksonomy for mobiles
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Daniele Quercia And Attacks?
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Daniele Quercia Further Research (join mobblog !)
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