Presentation is loading. Please wait.

Presentation is loading. Please wait.

Caché: Caching Location-Enhanced Content to Improve User Privacy Carnegie Mellon University Shahriyar Amini, Janne Lindqvist, Jason Hong Jialiu Lin, Eran.

Similar presentations


Presentation on theme: "Caché: Caching Location-Enhanced Content to Improve User Privacy Carnegie Mellon University Shahriyar Amini, Janne Lindqvist, Jason Hong Jialiu Lin, Eran."— Presentation transcript:

1 Caché: Caching Location-Enhanced Content to Improve User Privacy Carnegie Mellon University Shahriyar Amini, Janne Lindqvist, Jason Hong Jialiu Lin, Eran Toch, Norman Sadeh June 30, 2011

2 Widespread Adoption of Location-Enabled Devices : 150M GPS-equipped phones shipped 2014: 770M GPS-equipped phones expected to ship (~5x increase!) Future: Every mobile device will be location-enabled (GPS or WiFi) [Berg Insight 2010]

3 Apps Reveal Private Information App reveals: –Time of Use –User Interest –Current Location Over time: –Mobility Behavior –Significant Locations –Socioeconomic Status? 3

4 Our Approach Pre-Fetch content for large regions Store content on mobile device Respond to queries using stored content Periodically update content 4

5 Pre-Fetching Insight Some location-based content are still useful even when old (time to live) 5 Update Rate Data Type Real-Time (STTL) Traffic flow, parking spots e.g. Loopt, PeopleFinder, Reno, Bustle Dailyweather forecasts, social events, coupons e.g. Dede Weeklymovie/theatre schedules, advertisements, crime rates e.g. Yelp!, GeoNotes, PlaceIts, Plac Monthlyrestaurant guides, bus schedules, geocaches e.g. Wikipedia (geo-tagged pages) Yearlymaps, points of interests, tour guides, store locators e.g. Google Maps, Starbucks, Wal-Mart Long Time To Live Long Time To Live

6 Feasibility of Pre-Fetching Content doesnt change too often –Average daily amount of change over a 5 month period Requires <20 MB for Pittsburgh, ~100 MB for NYC 6

7 Pre-fetching Content Geo-coordinates are continuous Content cannot be pre-fetched for every point Use a grid to discretize space 7

8 Caché Architecture 8

9 Application Design Developer defines: –Size of cells –Content update rate –Query string 9

10 Application Installation Regions of interest: –15213 –Pittsburgh, PA Pre-fetch radius –1 km 10

11 Content Download Pre-fetch only when: –Plugged in –Connected to WiFi Pre-fetch every cell Update content at defined update rate 11

12 Content Retrieval Assume fresh content Retrieve content from a single cell Content miss results in a live request to LBS 12

13 High Content Hit Rate! Evaluation Based on Mobility Datasets –Locaccino: location-sharing –Place naming: label location 13 Radius (miles)LocaccinoPlace Naming 586%79% 1087%84% 1587%86%

14 Caché Android Service Android background service for apps –Apps modified to make requests to service –Service only pre-fetches when device is plugged in and connected to WiFi 14

15 Limitations Doesnt work for –Rapidly changing content (STTL) –Apps with client/server interaction (Facebook) –Apps with server computation (Navigation) Burden falls on the developer –Developer responsible for defining cell size and content download parameter New regions have to be specified before use 15

16 Our thoughts Merit: interesting method to protect privacy Cannot provide absolute privacy Hard to switch between privacy-protected mode and normal mode 16

17 Conclusion The most private request is the one you dont make. 17 Feasibility analysis: STTL and LTTL, storage Implement the privacy protected system Two evaluations: human mobility dataset and open source application

18 Locaccino December 2008 to October 2009 Top 20 users 5 female Grads, Undergrads, Faculty, Research Dev 18

19 Place Naming Ages 19 to 46 Spring, Summer, and Fall % female in Spring (N = 33) 40% female in Summer (N = 26) 30% female in Fall (N = 10) 19

20 Study of Mobility Traces How often will queries be cached? –Locaccino: Top 20 people, 460k traces –Place naming: 26 people, 118k traces –Pre-Fetch newly visited regions over night 20 Radius (miles)LocaccinoPlace Naming 586%79% 1087%84% 1587%86% Radius (miles)LocaccinoPlace Naming 596%79% 1097%85% 1597%87%


Download ppt "Caché: Caching Location-Enhanced Content to Improve User Privacy Carnegie Mellon University Shahriyar Amini, Janne Lindqvist, Jason Hong Jialiu Lin, Eran."

Similar presentations


Ads by Google