Presentation on theme: "ParkSense: A Smartphone Based Sensing System For On-Street Parking -- mobicom 2013."— Presentation transcript:
ParkSense: A Smartphone Based Sensing System For On-Street Parking -- mobicom 2013
Traditional methods SFPark: wireless sensor nodes embedded into asphalt( 沥青公路 ) at each parking location Google OpenSpot: allow drivers to mark a parking spot.
Primary Problem. How to detect the evacuation of parking space?
A sequence of specific actions
Typical approach GPS based location – significant amount of time to acquire an initial fix – power hungry Network based location – perform a scan for surrounding wifi – offers relatively coarse grained location
Performing passive wireless scans is the lowest energy operation compared to other location sensors. This motivates us to explore the wireless interface as a sensor to sense driver mobility.
Sensing that the user has returned to the parked vehicle location. Detecting the user is in a moving vehicle after returning to the parking location.
How to sense the user has returned to the parked vehicle location?
User returning to vehicle wireless signature(why?) – SSIDs of the Wifi access points. – the number of times a beacon frame was received from each AP. capture a wireless signature during payment phase.
User returning to vehicle periodically perform new wireless scans, create new signature.(S t and W t ) Compare the signature – S t, W t with S p, W p Optimize – define the signature over a set of scans rather than a single scan. – AP was visible in all the scans gets a higher weight Matching function
How to detect the user is in a moving vehicle after returning to the parking location?
User driving away Walking OR Driving ?
User driving away vehicle traveling follow a certain pattern what effect do these have on the wireless beacons observed by the mobile device inside the vehicle? – compute the Jaccard similarity.
Special Cases After parking, the driver drives away in a friend’s car,two cars are closed to each other. A driver parks a vehicle and give the key to someone else. The driver returns and unparks as expected, but immediately gets stuck in the traffic.