Assessment of Multi-Hop Interpersonal Trust in Social Networks by 3VSL Guangchi Liu, Qing Yang, Honggang Wang, Xiaodong Lin and Mike P. Wittie Presented by Guangchi Liu Department of Computer Science Montana State University Bozeman, MT, USA E-mail: guangchi.liu@msu.montana.edu IEEE INFOCOM 2014, Toronto, CA
Motivation 2
Motivation Ask Yourself: How to trust someone you have never known before? Trustor? Trustee Alice David 3
Motivation Probably, If Trustor Trustee Alice Bob David Transitivity of Trust [1] [1] Falcone, Rino, and Cristiano Castelfranchi. "Transitivity in trust a discussed property." (2010). 4
Motivation Then, How Should Alice Trust David? Trustor Trustee Alice Bob? David 5
Motivation Complex Topology: Harder Cases?? Parallel Topology? Bridge Topology Arbitrary Topology 6
Motivation Finally, we could expect. Small World Network Six degrees of separation 7
Applications 8
Applications Consumer-to-Consumer Recommendation Systems Untrustworthy User Trustworthy User Seller Buyer 9
Applications Active Friending in OSNs [2] Weak Relation Strong Relation Trustworthy User Target User Finder [2] Yang, De-Nian, et al. "Maximizing acceptance probability for active friending in online social networks." Proceedings of the 19th ACM SIGKDD international conference on Knowledge discovery and data mining. ACM, 2013. 10
Applications Sybil Identification Untrustworthy User Trustworthy User Unknown user User? 11
Contributions 12
Contributions Methodology Three-Valued Subjective Logic (3VSL) Multi-hop trustworthiness assessment Advantage Applicable to Complex Topology Be able to handle any large scale social network Validation Real World Experiment 100+ participants in online survey 13
Related Works 14
Related Works 3VSL Bayesian Network Hidden Markov Model Subjective Logic Artificial Intelligence Methods Random Walk Community Analysis Graph Partitioning Graph Theory Methods 15
Three-Valued Subjective Logic (3VSL) 16
3VSL: Opinion Vector Interpersonal Trust: Is David telling the truth? Positive Uncertain Negative Impression Trustor Opinion Trustee Alice David 17
3VSL: Opinion Vector Mom Alice s Evidences: Posteriori Evidence? Interaction History Positive Uncertain Negative Impression 18
3VSL: Opinion Vector Stranger Alice s Evidences: Priori Evidence Cognition in Mind Positive Uncertain Negative Impression 19
3VSL: Opinion Vector Priori Evidence + + + Posteriori Evidence Positive Uncertain Negative Impression 20
3VSL: Opinion Vector Dirichlet Distribution: + f ( p, p,, ) 1 2 1 (1 p p ) p p B(,, ) 1 1 1 1 2 1 2 Positive Uncertain Negative p 1 p 2 p 3 # # # : P 1 P P 3 1 2 21
3VSL: Opinion Vector 1 f ( p, p,, ) (1 p p ) p p B(,, ) 1 1 1 1 2 1 2 1 2 Positive Uncertain Negative EP ( ) 1 EP ( 2) = EP ( ) 3 # # + # + # # # + # + # # # + # + # 22
3VSL: Opinion Vector Positive EP ( ) 1 Uncertain 2 Negative EP ( ) EP ( 3) Impression # # + # + # # # + # + # # # + # + # # + # + # Positive # + # + # # + # + # # + # + # Pos-uncertain Negative + + 23
3VSL: Opinion Vector Opinion Vector A b X Positive n A X Pos-uncertain A d X Negative A e X A a X Impression 1 A A A A A A X X X X X X [ b, d, n, e, a ] A Opinion 24 X
3VSL: Opinion Vector Expected Belief Positive Pos-uncertain Negative Impression 1 E( ) b a n e 3 A A A A A X X X X X A X 25
3VSL: Opinion Vector Is David telling the truth? Opinion of David s Mom E( ) 0.33 0.442 0.45 0.5 0.05 Opinion of a Stranger E( ) 0.33 0.1 0.5 26
Multi-hop Trust Computation in OSNs: w v i e v j G(V, E, W) v? u 27
3VSL: Discounting Operation Operation for Trust Propagation 28
3VSL: Discounting Operation A D Alice A B Bob B D David Positive Uncertain Negative Positive Uncertain Negative 29
3VSL: Discounting Operation A B B D? A D Positive? Uncertain Negative 30
3VSL: Discounting Operation B D A D Distortion Alice A B Bob B D David 31
3VSL: Discounting Operation Absorbing Process Hop # Alice A D David 2 Hops Bob B D David 1 Hop 32
3VSL: Discounting Operation A B Discounting Operation: (, ) B D A A B (, ) D B D A B B D Alice Bob David A [ b A, d A, n A, e A, a A ] B B B B B B A A B bd bb bd A A B dd bb dd (, ) n 1 b d e A B ed ed A A ad ad A B A A A B B D D D D D B [ b B, d B, n B, e B, a B ] D D D D D D 33
3VSL: Combining Operation Operation for Trust Fusion 34
3VSL: Combining Operation A 1 D A D Alice David A 2 D A 1 D A 2 D Positive Positive Uncertain Uncertain Negative Negative 35
3VSL: Combining Operation Posteriori Evidences Priori Evidences A 1 D A 1 D Positive + Positive Pos-uncertain Negative + + Pos-uncertain Negative Independent Evidences Dependent Evidences Positive Pos-uncertain Negative A D Positive Pos-uncertain Normalize Negative 36
3VSL: Combining Operation A1 A2 Combining Operation: (, ) Alice A1 A2 (, ) A D D D A 1 D A 2 D David [ b, d, n, e, a ] A 1 1 1 1 1 1 D D D D D D A A A A A A D D D D D D [ b, d, n, e, a ] 2 2 2 2 2 2 D D b d 1 2 (, ) n A1 A2 A2 A1 A D D D D D A A A A ed ed ed ed 1 2 2 1 A1 A2 A2 A1 A D D D D D A A A A ed ed ed ed 1 2 2 1 A1 A2 A2 A1 A A A D D D D D D D A A A A ed ed ed ed e a 1 2 2 1 A2 A1 A D D D A A A A ed ed ed ed A D a b e A D b e d e d e n e e e n e 1 2 2 1 37
3VSL: Property Method 1: A B1 A B2 ( (, ), (, )) B C B C Method 2: A B1 B2 (, (, ) B C C Step.1 Step.1 Step.2 Equivalent Step.2 Step.3 38
3VSL: Topologies Bridge Topology Arbitrary Topology Large Social Networks 39
Evaluation 40
Evaluation: Real World Validation Goal Accuracy of 3VSL in Real Social Network Topology 1. 2. Method : Online Questionnaire [3,4] (100+ samples) 1. Error = ( ) ( ) 2. Error = ( ) ( ) [3]. Xiaoming Li and Guangchi Liu. Online Trust Survey. http://www.cs.montana.edu/yang/trust-us, 2013. [4]. C. Johnson-George and W. C. Swap, Measurement of specific interpersonal trust: Construction and validation of a scale to assess trust in a specific other. Journal of Personality and Social Psychology, vol. 43, no. 6, pp. 1306 1317, 1982. 41
Evaluation: Real World Validation 42
Evaluation: Numerical Analysis Goal 3VSL Vs. Common Sense Topology 1. 2. 3. Method E( )? 43
Evaluation: Numerical Analysis E( )? 44
Evaluation: Numerical Analysis E( )? 2 1 45
Evaluation: Numerical Analysis E( )? 46
Conclusion 47
Conclusion Three-Valued Subjective Logic 48
Thank You! Q & A Guangchi Liu (Luke) 刘光迟 ( 劉光遲 ) Networking Lab, Dept. of Computer Science Montana State University, MT, United States LinkedIn: www.linkedin.com/pub/guangchi-liu/60/a96/961/ E-mail: guangchi.liu@msu.montana.edu IEEE INFOCOM 2014, Toronto, CA
Backup I Trust Trust (Cognitive) Trust (Probabilistic) 50
Backup II Single hop trust assessment Wang, Yao, and Julita Vassileva. "Trust and reputation model in peer-to-peer networks." Multi Hop Trust Computation Jøsang, Audun. "A logic for uncertain probabilities." Bayesian Network Trust Assessment (AI Methods) Subjective Logic (SL) HMM Model Dynamic of Trust ElSalamouny, Ehab, Vladimiro Sassone, and Mogens Nielsen. "HMM-based trust model." 51
Backup III Subjective Logic 3VSL (, ) 1 2 (, ) 1 2 Collapse Constant Large Social Networks Large Social Networks 52