Wireless Gossiping for Social Networking

1. Wireless Gossiping for Social Networking Maarten van Steen VU University Amsterdam Department of Informatics

2. Overview • Background • Wireless gossiping: • from point-to-point to broadcasting • Social computing • detection of social interactions • dissemination of observed interactions • Social games • Some experiments • Stimulating social mingling • Crowd management • Measuring densities • A hybrid approach • Outlook Wireless gossiping for social computing

3. Wireless gossiping • We’ve been working a lot on point-to-point gossiping protocols in wired systems • Wireless systems: • broadcasting is the default, not point-to-point • links are often unreliable and asymmetric • no random selection across all the nodes Wireless gossiping for social computing

4. From p2p to broadcast Wireless gossiping for social computing

5. From p2p to broadcast Wireless gossiping for social computing

6. From p2p to broadcast Wireless gossiping for social computing

7. From p2p to broadcast Wireless gossiping for social computing

8. From p2p to broadcast Wireless gossiping for social computing

9. Main operations • Handle incoming messages • Remove duplicates • Keep latest • Update data store • If repeated, remove item • Else if space available, then store • Else replace randomly chosen item • Replaced items are moved to output buffer, if room • Select items to broadcast • Output buffer contains items removed from store • If space, publisher can insert own item Wireless gossiping for social computing

10. Chalcedony nodes • LED display • microphone • accelerometer • XMEGA128 processor • 8 kB SRAM/128 kB flash • slot for 8 MB SD card • logging! Wireless gossiping for social computing

11. Social games: detecting interactions • Simply measure and display social interactions: • Ranges are kept short, such that only face-to-face encounters will lead to mutual detection of nodes • Measure minimal duration and interpret as interaction • Nodes broadcast detections, which are sniffed and forwarded to visualizer Wireless gossiping for social computing

12. Social games: detecting interaction Wireless gossiping for social computing

13. Social games: stimulating mingling • Assume people belong to different groups • If Alice from group 1 interacts with Bob from group 2, Alice and Bob will earn credits for their group. • Group credits are disseminated to be seen by every member. • Goal: earn as many credits for your group as possible. • Technical issues: • Efficient dissemination schemes • Accurate interaction measurements Wireless gossiping for social computing

14. Speculative: crowd management • Measure social interactions • Can we identify social (sub)groups? • To what extent can we detect movements? • Pick up and process audio and other signals • Can we pick up sounds that indicate potentially dangerous situations (screams, gunfire, etc) • Measure (local) densities • High density areas may indicate dangerous situations Wireless gossiping for social computing

15. Speculative: crowd management • Combine in-network and offline processing Wireless gossiping for social computing

16. Outlook • Coming months: • Turning the prototype testbed into a robust system • Implementing a few social games • Concentrate on reliable sampling of network traffic • In 2011: • Large-scale trace-driven simulations • Concentrate on: • supporting and realizing ultra-low duty cycling • automatic reintegration of partitioned networks • Speculative: • Real-world experiments on 5000+ node networks Wireless gossiping for social computing