Title: iFIND: A PeertoPeer Application for Real Time Location Monitoring on the MIT Campus
1iFIND A Peer-to-Peer Application for Real Time
Location Monitoring on the MIT Campus
- Sonya Huang, Francois Proulx and Carlo Ratti
- Prepared for CUPUM 07
2Motivation
- Increasing availability of Location-Based
Services (LBS) in urban settings - For users enhanced information about local area
through location-specific content - For planners data about location-specific user
behavior, e.g. transportation, pedestrian
movement - How can we reconcile increased data about user
location and privacy concerns?
3iFIND
- A social friend-locating application tailored to
the MIT campus - Calculates users positions from signals of
nearby 802.11 (WiFi) access points - In WiFi-dense areas, 5-6 meter accuracy on
average - In sparse areas, 10-50 meter accuracy
- Share location information with allowed users
4Network-centric LBS
- More common paradigm of LBS (e.g. Loopt)
- Geo-locations of beacons (e.g. access points,
cell towers, satellites) stored in a central
server - Device sends beacon data to server, which returns
location - Network connection necessary
- Easier to set up only one copy of geo data and
software required
5Device-Centric LBS
- Many types of mobile devices are capable of
self-positioning (e.g. GPS, WiFi), if - Geo-location of beacons are known
- Device has software to calculate position from
beacon locations - Network connection not necessary
- More computationally demanding on device
requires data and software
6Diagram of Positioning Process in iFIND (based on
Intel Place Lab)
User brings device to WiFi-covered area
7Diagram of Positioning Process in iFIND (based on
Intel Place Lab)
Device detects identifiers of access points
8Diagram of Positioning Process in iFIND (based on
Intel Place Lab)
Software calculates position of device locally
9Communication Scenario with Two Users
3. Alices locationKAB
Alices iFIND Locator
Bobs iFIND Locator
6. Bobs locationKAB
2. PKBKAS
5. PKAKBS
1. Request for friends certificatesKAS
4. Request for friends certificatesKBS
iFIND Server
10Extensions of Device-Centric LBS
- Retrieve annotated location information from
device when position is calculated - May be downloaded (Place Lab)
- May be user-created (Bustle)
- Communicate location information with peers,
bypassing network and central server (iFIND) - Allow users to delegate permissions to other
users (Hengartner Steenkiste)
11Comparison of Selected Location-Based Information
Sharing Services
12(No Transcript)
13Using the iFIND Framework for Centralized Data
Collection
- Data-collection servers act as friends of iFIND
users - Users choose servers with whom they will share
location and other information, such as - Answers to survey questions posted by the server
- Information that can identify users (IP, MAC
address) needs to be stripped from transmitted
data - Connect through anonymizing network, e.g. Tor
(the onion router)
14Diagram of iFIND Setup with Collection Server
Question, Identifying info
Question
iFIND Locator
Tor
Answer, Location, Identifying info
Answer, Location
15Applications of the Framework
- Government
- Collect geo-coded survey answers
- Marketing
- Distribute location-based ads that can be
retrieved locally on users devices - Collect geo-coded statistics on ads viewed
- Users can aggregate statistics before sending
- Emergency Evacuation
- Users send own location to server in case of
emergency - Server returns evacuation instructions
16Comparison of Application Scenarios
17Further work
- Other methods for added privacy protection
- Higher aggregation of statistics before sending
- Noise
- Integrating new 802.11(v) standards
- Access points capable of broadcasting their own
location, i.e. no calculation needed - Integrating E911
18http//ifind.mit.edu