1. Houtan Shirani-Mehr, Farnoush Banaei-Kashani and Cyrus Shahabi
Using Location Based Social Networks for Quality-aware Participatory Data Transfer
Houtan Shirani-Mehr, Farnoush Banaei-Kashani and Cyrus Shahabi
Infolab, University of Southern California
Second International Workshop on Location-Based Social Networks (LBSN’10)

2. Outline Introduction Problem Definition A Case Study
Conclusions and Future Work

3. Introduction D

4. Data Transfer Media Wireless or wired communication infrastructures
Installing and using such infrastructures may be expensive and/or impossible

5. PDT B D S A Data Transfer in Real world Data Transfer in Virtual world
LBSN D B
LBSN
LBSN D D D D S
LBSN A D

6. PDT Network of real world connections
Network of virtual world connections

7. Different PDT Variations
Individual is a source
Individual is a destination
Example
Yes No
Participatory sensing
Advertisement propagation
Temperature monitoring
Propagating hazardous road conditions

8. Quality of Transferred Data
Individual is a source
Individual is a destination
Example No
Temperature monitoring
Yes
Participatory sensing
Advertisement propagation
Propagating hazardous road conditions
Sources Placement
Data Routing
Q(P): quality of transferred data during T

9. Problem Definition: Quality-Aware PDT (Q-PDT)
Input
Sources S={s1,s2,…,sn}
Destinations D={d1,d2,…,dm}
Individuals U={u1,u2,…,uo}
Constraints
Devices should be reachable
An LBSN L to specify friendship relation
Communication resources d2 d1
Q-PDT is NP-hard (the proof can be found in the paper)
Objective
To maximize Q(P) during T by
Placing data sources and destinations
Instructing optimal trajectories

10. Case Study Individual is a source Individual is a destination Example
Yes No
Participatory sensing
Advertisement propagation
Temperature monitoring
Propagating hazardous road conditions

11. Methodology T=30 minutes PDT participants Individuals data transfer
Synthetic social network (scale free model) with 500 nodes
Participants movements
GPS tracks of vehicles in the city of Beijing
Individuals data transfer
When vehicles pass by, data is transferred
Each individual uses virtual network on average twice to transfer data during T
Heuristic approach to place data sources
Located in the locations with the highest frequency of visit and at least 1km apart

12. Results

13. Conclusions and Future Work
Introduced variations of the problem of Q-PDT
Studied the complexity of Q-PDT
Future work
Development of efficient heuristics for different Q-PDT variations