1. Trust and Reputation Management in an Web-Enhanced World Zhaoyuan Zhang Email: zz2198@columbia.edu

2. Introduction of trust and reputation management 1 2 3 Preview Models for trust and reputation management Utilization of the models

3. Why trust and reputation management?

4. Emails

5. E-Commerce

6. Cloud Computing

7. Gain knowledge about unknown web services More efficient investments Helpful in making decisions Less risks REASONS

8. Agents Trusting agent: “An entity who has faith or belief in another entity in a given context and a given time slot” （ Chang, Elizabeth. Trust and Reputation for Service- Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Page: 27. Johns Wiley & Sons; 2006. ） Trusted agent: “An entity in whom faith or belief has been placed by another entity in a given context and at a given time slot” （ Chang, Elizabeth. Trust and Reputation for Service-Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Page: 28. Johns Wiley & Sons; 2006. ）

9. A time slot is “a period of time … defined as the breadth or duration of time over which the trust value is collected” Chang, Elizabeth. Trust and Reputation for Service-Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Page: 40. Johns Wiley & Sons; 2006

10. Trust is “defined as the belief the trusting agent has in the service provider’s willingness and capability to deliver a mutually agreed service in a given context and in a given time slot”. (Chang, Elizabeth. Trust and Reputation for Service-Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Page: 27. Johns Wiley & Sons; 2006.)

11. Trust Recommendation Trust recommendation is “a method that helps to form a trust relationship by deriving the initial trust value, also known as reputation based on references or recommendations collected from other parties”. (Chang, Elizabeth. Trust and Reputation for Service-Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Page: 40. Johns Wiley & Sons; 2006.)

12. Models for Trust and Reputation Management Deterministic Approach Bayesian Approach Fuzzy Approach Trust Models

13. Deterministic Approach Trust and Reputation for Service-Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Page: 251. Johns Wiley & Sons; 2006.

14. Deterministic Approach  Two agents:  Trusting agent: web service user  Trusted agent: one or several third party agents  Trusted agent gives the trust recommendation  Trusting agent analyzes the trust recommendation from trusted agents  Analysis is based on a period of time

15. A negative historical experience has a value of 0 Bayesian Approach Bayesian Theorem Use a web service’s historical performance to predict the future performance A positive historical experience has a value of 1 Use historical trust value (history) of a web service as the condition:

16. Fuzzy Approach Reliability Availability Security Define fuzzy sets of expected results of a web service from different criteria: Use a web service’s historical performance statistics For each record of the history, compare it from each aspect with the defined result sets

17. . Amazon’s Mechanism “Our very best sellers have a close to 0% Negative Feedback Rate… A 0-2% negative feedback rate indicates a good performance of a seller. While a negative rate of greater than 5% means there is some problem with the business practice…The feedbacks are 12-month based…” http://www.amazon.com/gp/help/customer/display.html?nodeId=1161284&#good Utilization of the models

18. Amazon’s Mechanism  Historical trust statistics  Fuzzy sets indicating different levels of potential performance results  Trust value is based on a time slot  Combination of different models

19. Conclusion  Introduction of trust and reputation management Why trust management? Definition of trusting agents, trusted agents, time slot, trust, trust recommendations.  Models for trust and reputation management Deterministic Approach: trust recommendation Bayesian Approach: historical trust value statistics Fuzzy Approach: fuzzy sets, historical trust value statistics  Utilization of the models  Combination of different models

20. References  Chang, Elizabeth. Trust and Reputation for Service-Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Johns Wiley & Sons; 2006.  M.wojcik. H.S. Venter. J.H.P. Eloff. Trust Model Evaluation Criteria: A Detailed Analysis of Trust Evaluation. 2008  Agudo, Isaac. Fernandez-Gago, Carmen. Lopez, Javier. A Model for Trust Metrics Analysis.  Zhu, Manling. Jin, Zhi. Trust Analysis of Web Services Based on a Trust Ontology. 2007.  Machala, Daniel. E-Commerce Trust Metrics and Models. Xeroxr Research and Technology  Receiving Amazon.com Feedbacks from Buyers. http://www.amazon.com/gp/help/customer/display.html?nodeId=1161284&#good  Nefti, Samia. Meziane, Farid. Kasiran, Khairudin. A Fuzzy Trust Model for E- Commerce.  Li, Wenjuan. Ping, Lingdi. Trust Model to Enhance Security and Interoperability of Cloud Environment. 2009  Thrope, Sean. Modeling a Trust Cloud Context. 2010.

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