Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Web Service Reputation: Conceptual ModelPresentation on November 26th 2008 Team Members:Sowmya J.BandalliKaren DoorePreeti GaneshMohan Title : Conceptual Model of Web Service ReputationAuthors : E. Michael Maximilien IBM and NCSU [email protected] P. SinghNorth Carolina State [email protected]: http://delivery.acm.org/10.1145/640000/637417/p36-maximilien.pdf?key1=637417&key2=0037377221&coll=GUIDE&dl=GUIDE&CFID=12837775&CFTOKEN=70178819Web Service Reputation: Conceptual Model A Web service represents a set of functions addressing a particular domain. Web Service Attributes:Generic Attributes:Domain Specific Attributes Reputation of a web service: Is a function of a web service that depends on attributes It depends on the relative importance of each attribute with respect to the agent using the service.Web Service Reputation: Important FactorsRelative Weights given to attributes Dependant on Agent Biases, Dependant on Specific DomainAttribute Aggregation Algorithm •Simple Majority, Other AlgorithmsEndorsers of the Service•Trust level of EndorsersHistory of Service•Services that are new won’t have as many endorsers•Older services have more history dataDampening Factors for Ratings•Allows a web service’s reputation to increase with improved service•More recent activity matters more than old activityConceptual Model of Web Service ReputationWASP – Web Service Agent ProxyConceptual Model UML Static Model Figures 2 & 31. A Web Service has 1 associated Reputation for an agent considering the service2. A Reputation of a service is a vector of attribute values3. A Reputation is determined by a reputation algorithm that aggregates attributes that are selected to be considered by the agent.4. A Reputation is also affected by a History, that keeps previous ratings for a particular service5. The rating for a particular service is determined for a particular principal (agent) using the RatingAlgorithm which takes into consideration the agent’s bias about the relative importance of each attribute.6. Endorsements by other Principals (agents) are also considered for determination of Reputation, the weighting given to an endorsement is dependant on the trust level of the Principal giving the endorsement.Conceptual Model of Web Service ReputationConceptual Model of Web Service ReputationAttributes ModelDomain are collections of attributes for a specific type of service Cross-Domain attribute: Domain specific attribute: Attributes: Each Attribute has a range, or set of allowed values: can be integer, percentage, Boolean, etc. Relative Weight of an AttributeRelative to Domain:User preferences:Characteristic function from Attribute value to RatingS-shaped: lower threshold and upper saturation levelMonotonically Increasing:Step-wise function:Temporal Characteristic: Decaying value of an attribute: Example travel delay, if a plane is delayed 10 minutes is tolerable, however a delay of 45 minutes may be intolerable because it causes problems with connecting flights.Generic and Domain Specific AttributesWeb Service Attribute Domains: For Web services that provide similar services, they will share common attributes, perhaps weighted differently For different domains.Example: Car rental service: Domains: Travel: Price, Flexibility of Reservation ChangesRetail: Price, InventoryFlexibility of Reservation Changes – may be used by some services to differentiate their service. Determining Attributes for a Domain: Suggestion: let the attributes for a domain be determined by community of users and providers for each domain.Ideally, want a system where new attributes can be added to domains, and where services can distinguish themselves by focusing on certain attributes. So that service doesn’t need to have values for all attributes.Conceptual Model of Web Service ReputationConceptual Model – Web Services Agent ProxyClient Desires Service: Client uses WSAP to access web services.Web Services Agent Proxy Consults with outside registries, reputation and endorsement agencies to find an appropriate provider of a desired web service.WSAP can use information about the user’s priorities with information in the form of reputation attributes and endorsements to determine the service which is optimum for the client.The WSAP can provide feedback to the reputation and endorsement agencies based on the WSAP and user experience to keep reputation and endorsement data up to
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