Inter-Context Trust Bootstrapping for Mobile Content Sharing (daniele quercia) (stephen hailes

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Inter-Context Trust Bootstrapping for Mobile
Content Sharing(daniele quercia)(stephen
hailes licia capra)
U C L
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What do I do?
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Research _at_
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what I research?
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Reputation Systems for Mobiles
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Whats that?
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Exampleantique markets
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Problem Visitors cannotsee 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 decideswhether 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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3. Similar contexts (? universal ontology)
Daniele Quercia
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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)
C
?
A
B
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Daniele Quercia

• Meant for the Web
• Proved on binary ratings

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• Algorithm rating
• unrated trust relationships (needed)

Daniele Quercia
C
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2
?
A
B
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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 gt 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 ?
Antiques
Coins
Chairs
Roman Coins
Greek Coins
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Daniele Quercia
Idea Users gt Dont share ontology gt Extract
features from their own ratings
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Daniele Quercia
Idea Users gt Dont share ontology gt Extract
features from their own ratings
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Daniele Quercia
How to extract?
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Daniele Quercia
Singular Value Decomposition
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Daniele Quercia
Beauty features not user-specified BUT learnt
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Tested on simulation with real parameters
Daniele Quercia
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Daniele Quercia
Tested on Nokia 3230 Max 3.2 ms !
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Daniele Quercia
What Ive told you is on mobblog UCL (google
it) under tag bootstrapping
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Daniele Quercia
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Daniele Quercia
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 !)