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Contextual Computing. Suman Nath Microsoft Research. Contextual Computing. Make computing context-aware Context: location, activity, preference, history A lot of progresses in location-aware services. Not enough …. Need to use other signals Do I like Italian restaurant?
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Contextual Computing SumanNath Microsoft Research
Contextual Computing Make computing context-aware • Context: location, activity, preference, history • A lot of progresses in location-aware services
Not enough … • Need to use other signals • Do I like Italian restaurant? • Am I walking? Do I drive 10 miles to eat? • Is it lunch time or dinner time? • Alone with family? • Queue time ? • How do we get them? • Ask users to release more contextual information • Rely on crowdsourcing • Challenges to address: • Energy: partially solved • Privacy: mostly unsolved Personal preference/history User’s context Real-time status
Energy • Many services require continuous sensing • Acquiring context is expensive • Many optimizations proposed • Not sufficient for continuous sensing • Phone will die in a few hours • Challenge: continuous sensing for a day without charging • Needs innovation: Efficient “Assisted” GPS
Low Power Assisted GPS • Not regular GPS replacement • Location-based services (e.g. mobile search) • Batched location estimation (e.g. path prediction) • Delay-tolerance positioning (e.g. geo-tagging photos) • Crowdsourcing Takes 1s to minutes Same for ~150KM 1ms NMS Requires a few ms code phase • Mobile phone sends to server: • Code phases • Cell tower ID • Time stamp • Server: • Computes NMS • Computes mobile location LEAP: A Low Energy Assisted GPS for Trajectory-Based Services, Ramos et al. Ubicomp 2011
Privacy: do we care? • News: iPhone keeps record of everywhere you go
Do people care? 48% 52% said they were "very or extremely concerned" about loss of privacy from using location-sharingapplications Are you worried about geolocation privacy? 48% seriously concerned, 32% little worried
Why is the stake high? Apple fined 1M won ($932) by South Korea over iPhone tracking allegations The suit now counts 26,691 plaintiffs => $26 million Lawmakers Demand Apple Clarify iPhone Tracking Capability Facebook fights new California privacy bill 'Do Not Track Me Online' privacy bill introduced by California Rep.Jackie Speier
PER Theorem Impossible to maximize all three Trivial to maximize any two Revenue/ Relevance Client-side Server-side Privacy No-result Efficiency Michaela Goetz and SumanNath, Privacy-Aware Personalization for Mobile Advertising, no. MSR-TR-2011-92, August 2011
My wishlist • My context-aware service knows what is relevant • Without affecting my phone battery much • Without me telling it much about my private context • Even if I release limited private information • My privacy is preserved (even with strong adversaries) • In future I can revoke my data • (Only) I can decide how my data is used and shared