A Semantic Peer-to-Peer Overlay for Web Services Discovery

1. A Semantic Peer-to-Peer Overlay for Web Services Discovery Shuang Kai

2. Agenda • Introduction • Thoughtway of our method • Semantic overlay node architecture • Routing Table & Neighborhood Table • Message Semantic Matching & Routing • Example • Experimental Evaluation • Conclusion

3. Introduction-1 • service discovery mechanisms • centralized registry • UDDI or DAML-S matchmaker • decentralized approach • centralized registry • single point failure • performance bottleneck

4. Introduction-2 • based on P2P technology • unstructured P2P network • limitation on the scalability • structured P2P networks based on DHT • logn routing hops – network of size n nodes • exact match

5. Agenda • Introduction • Thoughtway of our method • Semantic overlay node architecture • Routing Table & Neighborhood Table • Message Semantic Matching & Routing • Example • Experimental Evaluation • Conclusion

6. Thoughtway of our method • structured P2P semantic method • different matching degree • extends the Plaxton mesh • dynamic semantic overlay network • keyword prefix routing to semantic prefix routing

7. Characteristic Vector - 1 • semantic service description • OWL-S or WSMO • characteristic vector • a series of numeric string • extract service’s information • input, output, Pre-conditions and Effects • ontological concept

8. Characteristic Vector - 2 • service description: • Advertisement1 = {C7, C6, C5, C4} • CV={10, 11, 0000, 0100}.

9. Agenda • Introduction • Thoughtway of our method • Semantic overlay node architecture • Routing Table & Neighborhood Table • Message Semantic Matching & Routing • Example • Experimental Evaluation • Conclusion

10. Semantic overlay node architecture -1

11. Semantic overlay node architecture -2

12. Agenda • Introduction • Thoughtway of our method • Semantic overlay node architecture • Routing Table & Neighborhood Table • Message Semantic Matching & Routing • Example • Experimental Evaluation • Conclusion

13. Routing Table • multiple rows • each rows holds a number of entries • semantic matching of the prefix up to an element in the CV

14. Neighborhood Table • Contains the nodeID and IP address of the peers • Set of peers that are closest to the local peer • Based on semantic similarity

15. Agenda • Introduction • Thoughtway of our method • Semantic overlay node architecture • Routing Table & Neighborhood Table • Message Semantic Matching & Routing • Example • Experimental Evaluation • Conclusion

16. Semantic Matching Degree • Exact • If advertisement S and request Q are equivalent • S ≡ Q • PlugIn • If S could always be used for Q • S is a plug-in match for Q, Q⊆S. • Subsume • If S is more general than Q • S is a Subsume match for Q, S⊆Q

17. Message Routing and Locating

18. Agenda • Introduction • Thoughtway of our method • Semantic overlay node architecture • Routing Table & Neighborhood Table • Message Semantic Matching & Routing • Example • Experimental Evaluation • Conclusion

19. Example Message ID C3C7CAC0 Subsume Exact

20. Agenda • Introduction • Thoughtway of our method • Semantic overlay node architecture • Routing Table & Neighborhood Table • Message Semantic Matching & Routing • Example • Experimental Evaluation • Conclusion

21. Experimental Evaluation - 1

22. Experimental Evaluation - 2

23. Agenda • Introduction • Thoughtway of our method • Semantic overlay node architecture • Routing Table & Neighborhood Table • Message Semantic Matching & Routing • Example • Experimental Evaluation • Conclusion

24. Conclusion • Our System • support semantic matching • ontological concept encoding scheme • based on the structured overlay network • dynamic Plaxton mesh-like network • Future work • improve the usability of this system

25. Thank you！