Mining and Composition of Emergent Collectives in Mixed Service-Oriented Systems

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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.

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  • July 29, 2011
  • July 29, 2011
  • July 29, 2011
  • July 29, 2011
  • July 29, 2011
  • July 29, 2011
  • Mining and Composition of Emergent Collectives in Mixed Service-Oriented Systems

    1. 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]
    2. 2. Environment and Motivation <ul><li>Open and dynamic environment </li></ul><ul><ul><li>humans and resources (e.g., services) </li></ul></ul><ul><ul><li>joining/leaving the environment dynamically </li></ul></ul><ul><ul><li>humans perform activities and tasks </li></ul></ul><ul><li>Massive collaboration in SOA/Web 2.0 </li></ul><ul><ul><li>large number of humans and resources </li></ul></ul><ul><ul><li>dynamic compositions </li></ul></ul><ul><ul><li>distributed communication and coordination </li></ul></ul><ul><li>Keep track of the dynamics to control </li></ul><ul><ul><li>future interactions </li></ul></ul><ul><ul><li>resource selection </li></ul></ul><ul><ul><li>compositions of actors </li></ul></ul><ul><ul><li>activity and task assignments </li></ul></ul>computational social network model
    3. 3. Application Scenario: Expert Web <ul><li>Process model is based on tasks and flow structure </li></ul><ul><li>Embedding of Web 2.0 collaboration tools </li></ul><ul><li>Connected experts provide online help and support </li></ul>[IS10] F. Skopik, D. Schall, and S. Dustdar. Modeling and mining of dynamic trust in complex service- oriented systems . Information Syst., 2010.
    4. 4. Expert Discovery in Crowdsourcing <ul><li>How do actor discovery and selection mechanisms work? </li></ul><ul><li>What is the technical grounding for the proposed system? </li></ul><ul><li>How can actors be flexibly involved in a service-oriented manner? </li></ul><ul><li>How do interactions and behavior influence future discovery? </li></ul>
    5. 5. Hubs and Authorities <ul><li>On the Web </li></ul><ul><ul><li>Hubs: pointing to authoritative pages </li></ul></ul><ul><ul><li>Authorities: are being referenced by other important pages </li></ul></ul><ul><ul><li>Recursive definition </li></ul></ul><ul><li>In social/collaborative networks </li></ul><ul><ul><li>Hubs: information “brokers” distributing work </li></ul></ul><ul><ul><li>Authorities: experts processing received work </li></ul></ul>Based on HITS algorithm (Kleinberg, J. ACM 1999)
    6. 6. Human-Provided Services <ul><li>Mixed System </li></ul><ul><ul><li>Mix of human- and software services collaboration </li></ul></ul><ul><ul><li>Humans provide services using SOA concepts </li></ul></ul><ul><li>Human-Provided Services (HPS) </li></ul><ul><ul><li>User contributions as services </li></ul></ul><ul><ul><ul><li>Service description with WSDL </li></ul></ul></ul><ul><ul><ul><li>Communication via SOAP messages </li></ul></ul></ul><ul><ul><li>Example: Document Review Service </li></ul></ul><ul><ul><ul><li>Input: document, deadline </li></ul></ul></ul><ul><ul><ul><li>Output: review comments </li></ul></ul></ul>[EEE08] D. Schall, H.-L. Truong, S. Dustdar. The Human-Provided Services Framework . IEEE 2008 Conference on Enterprise Computing, E-Commerce and E-Services (EEE), Crystal City, Washington, D.C., USA, 2008. IEEE.
    7. 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.
    8. 8. Metric Definitions <ul><li>Define metrics </li></ul><ul><ul><li>emergency support: fast and reliable responses </li></ul></ul><ul><ul><li>neglect others, e.g., costs </li></ul></ul><ul><li>Calculate metrics in the scope of interactions (here: requests for support (RFSs)) </li></ul><ul><ul><ul><li>average response time </li></ul></ul></ul><ul><ul><ul><li>activity success rate </li></ul></ul></ul>
    9. 9. Delegation Behavior (1/2) u w v z y x t s q … nodes … social network relations (FOAF knows ) … delegation … reply and rewarding <ul><li>Context Tags: </li></ul><ul><li>Applied to interaction links </li></ul><ul><li>Metrics: </li></ul><ul><li>Responsiveness </li></ul><ul><li>Success rate </li></ul>r
    10. 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. 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
    12. 12. ExpertHITS (2/2) Reputation w v z Q <ul><li>Calculate reputation in scope of interaction contexts (expertise) </li></ul><ul><li>Hub score </li></ul><ul><ul><li>Rating through authorities based on delegation behavior: </li></ul></ul>u H(u;Q) = ∑ v:u->v w Q vu A(v;Q) w Q wu w Q zu <ul><li>Authority score: </li></ul><ul><ul><li>Rating through hubs based on reliability in processing delegated tasks </li></ul></ul>A(v;Q) = ∑ u:u->v w Q uv H(u;Q) w v z Q u w Q uv w Q vu
    13. 13. <ul><li>Generate artificial interaction data imitating real collaboration environ- ment ( preferential attachment) </li></ul><ul><li>Small and medium scale networks (100 to 1000 nodes) </li></ul><ul><li>Concurrent processing time: </li></ul><ul><li>For small-scale networks, on average 19 seconds can be expected under different load conditions (50-500 concurrent requests) </li></ul>ExpertHITS Results (1/2)
    14. 14. <ul><li>Measuring quality and impact of rankings ( see paper ) </li></ul><ul><ul><li>Standard HITS algorithms versus ExpertHITS </li></ul></ul><ul><li>Ranking metrics </li></ul><ul><ul><li>Relative ranking change </li></ul></ul><ul><ul><li>Quality </li></ul></ul><ul><li>ExpertHITS promoting well-connected and rated hubs </li></ul><ul><li>Approach guarantees the discovery of reliable “entry points” to the Expert Web </li></ul>ExpertHITS Results (2/2)
    15. 15. ExpertHITS Online Help and Support (1/2) Formulate Query (Constraints)
    16. 16. Online Help and Support (2/2) Discovery and Interactions
    17. 17. <ul><li>Thanks! </li></ul>Daniel Schall and Florian Skopik Distributed Systems Group Vienna University of Technology, Austria [email_address] [email_address]

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