1. Localized Distance-Sensitive Service Discovery in Wireless Sensor and Actor Networks IEEE Transactions on Computers, Vol. 58, No. 9, September 2009 Xu Li, Nicola Santoro, and Ivan Stojmenovic 1 postdoctoral fellow at SITE, University of Ottawa, and CNRS/INRIA, France. 2 University of Waterloo, Canada 3 University of Ottawa, Canada.

2. Outline  Introduction  iMesh Protocol  Performance Evaluation  Conclusions

3. Introduction Destination Static sensor Moving object

4. Introduction

6. A

7.  In this work, the authors propose a novel solution to address the distance-sensitive service discovery problem energy saving timely response

8. Information Mesh Construction Service Provider (SP) Service Consumer (SC) A B C

9. Information Mesh Construction

10. Blocking Rule  A common node u of the residing rows/columns of two SPs a and b (a≠b) stops the further propagation of the information of a, iff |ua| > |ub| |ua| = |ub| ∩ colline(a, b) |ua| = |ub| ∩ ~colline(a, b) ∩ horizon(b) a b u b u a

11. Information Mesh Construction

13. c b a d

14. Extension Rule  A node u, at which an SP-node a orthogonally blocks another SP-node b, sends the information of a to b along the backward path from which it receives b’s information.  The information of a does not travel all the way to b but stops at the point where the path intersects the bisector between a and b. c b a u Extension area d

15. Information mesh in an arbitrary sensor network – no void areas

16. Information mesh in an arbitrary sensor network – In the presence of void areas

17. Performance Evaluation  Evaluation Metrics Total Number of Construction Messages (TNCM):  the total number of messages transmitted in the network for information mesh construction Number of Construction Messages per SP (NCMSP):  the average number of messages generated by an SP for the purpose of information mesh construction Number of Search Messages per SC (NSMSC):  average number of lookup messages generated by an arbitrary SC (reply messages are not counted)

18. Performance Evaluation  grid networks of size:32 × 32, 45 × 45, ‧‧‧, 100 × 100  SPs are randomly scattered in the network.  Percentage of SPs (PSP) in the network varying from 0.1 to 1.5 percent.

19. Message overhead – 10,000 nodes

20. iMesh versus Quorum – size 10,000

21. iMesh versus Quorum – size 1,000

22. PDOCC iMesh-AiMesh-B

23. Conclusions  In this work, the authors formalize the distance-sensitive service discovery problem information blocking rule information extension rule.  Extended to different node densities different topological holes

24. Thank You ~