View
574
Download
2
Category
Tags:
Preview:
DESCRIPTION
Presented at MobiQuitous, Toronto, Canada, July 2009.
Citation preview
Multi-Layered Friendship Modeling for Location-based Mobile
Social NetworksNan Li and Guanling Chen
Department of Computer Science, University of Massachusetts Lowell
July 14, 2009Toronto, Canada
MobiQuitous 2009
Online Social Network Success• Popular (half billion ww users)• Sticky (26m per day)
OSN Goes Mobile
• Already top Web destinations on smartphones
• Unique feature – location– GPS-enabled phones– Sharing current location– Attaching location to user-generated content
• Outlook– LSN >$3.3B revenue by 2013 (ABI)
• Dodgeball, Loopt, Brightkite, WhrrlGoogle Latitude, Foursquare
Brightkite
• Startup founded 2005, Denver CO– Angel funding $1M, 03/2008– Private beta, 04/2008– Opened to public, 10/2008
• User activity– Check in, status update, photo upload– All attached with current location– Updates through SMS, Email, Web, iPhone…
• Social graph with mutual connection– See your friends’ or local activity streams
Usage Snapshot
Contributions
• Data collection from Brightkite– 19k users; 1.5m updates
• Quantitative correlation model for friendship– User tags, social graph, location/activity
• Evaluation using 10m training data and 45d test data– Outperformed than Naïve Bayes classifier
or J48 decision tree algorithms
Data Collection
• Brightkite Web APIs• 12/9/08-1/9/09: 18,951 active users• Back traced to 3/21/08: 1,505,874
updates• Profile: age, gender, tags, friends list• Social graph: 41,014 nodes and
46,172 links• Testing data: next 45 days had 5,098
new links added
Tag Cloud
Basic Approach
• Coming up metrics that– Differentiate friends and non-friends– Tags, social graph, location, activities
• Combination of the metrics• Training and testing with traces
Using Metrics
Metric Combination
Social Graph
Social Graph Metric
Tag Graph
• 1000 most popular tags as the nodes• Complete graph• Link weight reflects likelihood of two
tags shared by friends
Tag Graph Metric
Location Graph
Location Graph Metric
Rank Value Result
Modeling Accuracy
• Take another 100,000 non-friend pairs– Not in training data
• Plus the newly added 5,098 friend pairs
• Sort the prediction values
ROC Curve
Top Recommendations
Information Gain
Worldwide buzz: Planetary-scale views on an instant-messaging network. J. Leskovec and E. Horvitz, June 2007.
Discussions
• Model stability as Brightkite grows– Does not require frequent re-calculation
• On-demand recommendation– Heuristics to speed up metric calculation
• Possible improvement– Different metrics, or combination methods
• “Private” updates– Conjectured to be few, but no proof
Related Work
• Industrial solutions: Facebook, Twitter– Technical details unknown
• OSN structural analysis– Aggregated behavior not suitable for
individual recommendations
• Collective filtering– User-item vs. user-user
Conclusion
• Correlated attribute combination has good friendship recommendation power– Interests, social graph, location
• Location metric is important– Gender and age not so much
• Future work– System implementation– Real-user action-based evaluation
Acknowledgement
• Anonymous reviewers• Shepherd- Sharad Agarwal• Best Paper Award committee
Recommended