a presentation made at xconf and iiwas kuala lumpur

1. Cache Prefetch and Replacement with
Dual Valid scopes for Location
Dependent Data in Mobile Environments
Mary Magdelene Jane F, Ilayaraja N, Ashwin Raghav
M, Nadarajan R, Maytham Safar

2. Prequel….
What is a Cache?
So many different types of Cache exist
All of these serve a similar purpose
How do Cache Systems Vary in LDIS and non LDIS
systems?
Lets deviate from the primitive purpose of a Cache.
What if the data is already available when it
is needed?

3. NN Query-- The Mechanism

4. The Repercussions....

5. Predict using semantic Relationships

6. Predict through experience

7. Getting it to Work!
We have explored Semantic prefetching. Predictive prefetching
is of greater relevence here.
Request:
• Location of the Client ( --Lat Long )
• Type of Resource ( eg. Hotel, Theatre )
Response
• Location of the Nearest Resource( --Lat Long )
• Resource Details ( eg. Menu at the restaurant, Specialties )
• Valid Scope ( Voronoi )
• The above 3 for the Predicted Resource
The assumptions
• Related services are queried in a sequence
• These services are typically geographically close

8. The Warehouse
Many records, each containing:
• Resource requested
• Location from where it was sent
Thresholds:
• Distance
• Query Gap
• Support & Confidence

9. Inside the Waiter's Brain

10. Distance--- A Parameter to mine Efficiently

11. Query Gap- To keep Semantic Relations in Tact

12. Single Valid Scope---The Unfair Arena

14. Single Valid Scope with Partitioned Cache---The Fair Arena

16. Dual Valid Scope --- The SOS Cache

17. Hits and Wastage--- A Trade off

18. Savings...

19. What we are doing right now!
• http://sourceforge.net/projects/mobilecachesimu/.
The Framework to test Caching Algorithms (FRACAS).
Published under the GPL.
• The drawback with prefetching. You may always bring in an
item that the client already has. This redundancy can be
removed at the implementation level.
• Browser and Non LDIS equivalent.
• Improving User Experience in Areas that experience low
Bandwidth.