1. Extracting Places from Traces of Locations Paper Authors Jong Hee Kang Benjamin Stewart William Welbourne Gaetano Borriello PowerPoint Author Michael Cook

2. 4 th Year Computer Science (Junior) 4 th Year Computer Science (Junior) Co-oping at Synovus Co-oping at Synovus Interests Interests Databases Databases Networking Networking Web Development Web Development Twin brother Twin brother

3. The Problem Location aware systems today are limiting Location aware systems today are limiting Place: An area of importance to a user Place: An area of importance to a user Usage Example: Usage Example: Cell phone goes to “silent” mode when entering a classroom Cell phone goes to “silent” mode when entering a classroom

4. Ideal Situation Requires little user interaction Requires little user interaction All important places are located All important places are located No false positives No false positives Works for indoor and outdoor places Works for indoor and outdoor places

5. Tracking User Movement Place Lab access points Place Lab access points Works indoors Works indoors

6. Popular Clustering Algorithms K-means Gaussian mixture model Large amounts of computation

7. Time-Based Clustering Streaming computation Streaming computation Small clusters ignored Small clusters ignored Time threshold and distance threshold can be changed Time threshold and distance threshold can be changed

8. Time-Based Clustering Result

9. Changing Distance and Time

10. d=30m t=300sec d=50m t=300sec d=300m t=600sec

11. Frequently Visited Places Not much time is spent at the place, but frequently visited Not much time is spent at the place, but frequently visited Different time threshold needed Different time threshold needed How to differentiate the place and in- transit motion? How to differentiate the place and in- transit motion?

12. Future Work Automatic labeling of places Automatic labeling of places Can use user’s calendar Can use user’s calendar Learn proper distance and time thresholds automatically Learn proper distance and time thresholds automatically

13. Critique Easy to read and understand Easy to read and understand Cool idea with practical applications Cool idea with practical applications WiFi hotspots not always available WiFi hotspots not always available Trying to do too much at once Trying to do too much at once Long duration places Short duration, frequent places

14. Questions?