Dieter Fox Keynote Location-Based Activity Recognition
<p>Mar 25, 2009 2:15 PM
 
Dieter is now at Univ of Wash Seattle...  robotics.
prev at CMU.
He was 
Chairman of AAAI in 2008.
 
Assisted Cognition for eg Alzheimers... make sure patients don't get loss... try to guess their goals,
when they're lost.
 
figure out what people are trying to do by oberving their routes.
 
Get location info from GPS;  infer where he is and mode of xport... bike, foot, car, bus.
 
use street mapes, bus routes, etc.
 
Also extend to indoor environ using   WIFI signal strenth instead of GPS
(triangulate with wifi instead of GPS.
 
Map is a  directed graph...  using Kalman filtering to handle noise.
 
He uses  DBN  Dynamic Bayesian Networks  to handle uncertainty.
to combine know sources...  main source is GPS  but also  prior routes,  expectations.
 
Once routes are learned can turn-off (or turn down sampling freq of GPS)  espec if person is on
a route the system has already learned.
 
Its trying to figure out where HOME is  (where you sleep)  where you WORK  where you visit, shop
Can infer mode of xport by velocity.
but  cars stop in traffic;  buses only go on certain routes.
 
Goal is to find and label trip segments... changes in mode of xport.
 
see   Liao-Fox-Kautz   AAAI04  or  AIJ-07.
 
Can see if person gets on wrong bus
 
also uses  conditional random field  (similar to DBN).
 
a1 thru aN  is an activity sequence....    work, drive, sleep work..
 
p1  thru ;N  are PLACE nodes  home work etc
 
in 2 weeks system gathers   50,000  GPS  data points.
 
INDOORS  use  WIFI.
 
Gaussian Process Regression to handle noise.   first order Markov.  particle filter.
 
They built a little box worn around the neck  with camera, light meter, accelerom, barometric pres to
help assess location;  soldiers wore it;
 
Also used  RFID tags  to monitor breakfast;;;;
 
tried  to do route finding for a robot using a maximize cost/benefit function....
desiderata:  go with the flow of the crow,  avoid collisions,  stay to the RIGHT,  ?  max distance to other people.
 
AAAI-SSS-09.
 
Eric Horvitz sitting in front... has 6th grade son.</p>