Complex service-oriented systems typically span interactions between people and services. Compositions in such systems demand for flexible interaction models. In this work we introduce an approach for discovering experts based on their dynamically changing skills and interests. We discuss human provided services and an approach for managing user preferences and network structures. Experts offer their skills and capabilities as human provided services that can be requested on demand. Our main contributions center around an expert discovery method based on the concept of hubs and authorities in Web-based environments. The presented discovery and interaction approach takes trust-relations and link properties in social networks into account to estimate the hub-expertise of users. Furthermore, we show how our approach supports flexible interactions in mixed service-oriented systems.

1. Mining and Composition of Emergent Collectives in Mixed Service-Oriented Systems IEEE Conference on Commerce and Enterprise Computing (CEC) 10-12 November 2010, Shanghai, China Daniel Schall and Florian Skopik Distributed Systems Group Vienna University of Technology, Austria [email_address] [email_address]

7. Monitoring and Logging <soap:Envelope xmlns:soap=... <soap:Header> <vietypes:timestamp value=&quot;2010-11-02T15:13:21&quot;/> <vietypes:delegation hops=&quot;3&quot; deadline=“...&quot;/> <vietypes:activity url=&quot;http://.../Activity#42&quot;/> <wsa:MessageID>uuid:722B1240−...</wsa:MessageID> <wsa:ReplyTo>http://.../Actor#Florian</wsa:ReplyTo> <wsa:From>http://.../Actor#Florian</wsa:From> <wsa:To>http://.../Actor#Daniel</wsa:To> <wsa:Action>http://.../Type/RFS</wsa:Action> </soap:Header> <soap:Body> <hps:RFS> <rfs:requ>Can you ...?</rfs:requ> <rfs:generalterms>...</rfs:generalterms> <rfs:keywords>...</rfs:keywords> <rfs:resource url=“...&quot;/> </hps:RFS> </soap:Body> </soap:Envelope> Distributed SOAP Interaction Monitoring Activity/Task Management Provisioning and Configuration IF Interaction Metrics Calculation [IS10] F. Skopik, D. Schall, and S. Dustdar. Modeling and mining of dynamic trust in complex service- oriented systems . Information Syst., 2010.

10. Delegation Behavior (2/2) u w v z y x t s q … nodes … social network relations (FOAF knows ) … delegation … reply and rewarding r Delegations and ratings relevant for a particular context

11. ExpertHITS (1/2) Query Context w v z y x t s q r ExpertHITS Query Q A : Required skills e.g., software engineering, compiler techniques ExpertHITS Query Q B : Required skills e.g., algorithms, social network mining Q A Q B u

15. ExpertHITS Online Help and Support (1/2) Formulate Query (Constraints)

16. Online Help and Support (2/2) Discovery and Interactions