1. YO-YO Leader Election
Lijie Wang

2. Using SPIN Used to detect design error in applications;
descriptions of distributed algorithms.

3. YO-YO Algorithm Minimum finding Consists two parts
Leader(smallest id node)
Consists two parts
Preprocessing
Iterations

4. Basic Components
Node Id
Neighbors
Edge
Between nodes
Voting through

5. Node Exchange its id with neighbors
Preprocessing
Node
Exchange its id with neighbors
Edge
Direction
Small->large (id)

6. DAG

7. Direction goes down
using different ico

8. Local minima ->source ->candidate
Candidates
Local minima
->source
->candidate
Preprocessing completed
Second part start…

9. Remove candidates Leave the only one
Iteration
Remove candidates
Leave the only one
Two phases
YO-
-YO

10. All sink done -> YO- end…
Source: ⊙->id-> out neighbors
Internal: ->all in neighbors-> ⊙->min->out neighbors
Sink: ->all in neighbors-> ⊙
All sink done -> YO- end…

11. -YO start… Sink: ⊙->Y ->min; ⊙-> N->others
Internal: ->all out neighbors-> ⊙
Receive at least one N: ⊙->N-> all in neighbors
Receive all Y: ⊙->Y->min; ⊙->N->others
Source: all out neighbors -> ⊙

12. Receive at least one N No longer a candidate How?...
Eliminate candidates
Receive all Y
Survives (this time)
Receive at least one N
No longer a candidate
How?...

13. Receive at least one N No longer a candidate Become sink or internal
Reverse N-edge
Modify DAG
Flip the link with N
Receive at least one N
No longer a candidate
Become sink or internal
With reversing
Sink and internal not become candidate
less candidate

14. Drag down the dead candidates
And start over…

15. YO- [2]

16. -YO [2]

17. Flip [2]

18. Count the only one candidate Become the leader
Termination?
Count the only one candidate
Become the leader
To reduce the message
To detect termination
Only left one source
Additional mechanism
Pruning

19. Pruning
Eliminate leaf
Eliminate redundant route

20. Pruning [1]

21. Pruning [2]

22. Pruning more [2]

23. Pruning [3]

24. Complexity With pruning Without pruning
Each phase: 2 messages each link
Number of phase: log (number of sources)
Total: 2*m*log(s)
With pruning
Though we do not know the exact number of reduced message in each iteration.
Surely, the communication cost will be less remarkable
Total: 2* 0 𝑖𝑡𝑒𝑟𝑎𝑡𝑖𝑜𝑛𝑠 𝑐𝑢𝑟𝑟𝑒𝑛𝑡 𝑙𝑖𝑛𝑘𝑠

25. Thank you For the spin result
Fail to intall Ispin on the 64-bit system
Try to use the Virtual Machine with a 32-bit system
Ispin result will be show in the final report
Thank you