BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:A Martingale Framework for Trust - Bruce Hajek\, University of Ill
 inois Urbana-Champaign
DTSTART:20100301T150000Z
DTEND:20100301T160000Z
UID:TALK22670@talks.cam.ac.uk
CONTACT:Sarah Lilienthal
DESCRIPTION:It is well known that as information grows about a random vari
 able\, the conditional expectation of the random variable given the inform
 ation evolves as a martingale. Therefore\, martingales naturally arise in 
 trust and reputation systems\, which involve the evolution of trust or rep
 utation with growing information. This work focuses on a particular decisi
 on problem--namely\, which links to probe in a network\, to assess the ove
 rall capability of the network. In essence\, the decision maker is trying 
 to establish the trustworthiness of a system by probing links within it. E
 ach link is assumed to have a random binary state\, fixed for all time\, a
 nd when a link is probed the decision maker obtains a noisy observation of
  the link state. A particular example is\nprobing links within a graph to 
 determine whether the links with state one span the graph. The conditional
  state of each link is a martingale\, and the conditional  probability tha
 t the overall network\nstate is good  is also a martingale.  Examples and 
 preliminary analysis are described in this talk.\n
LOCATION:Seminar Room 1\, Isaac Newton Institute for Mathematical Sciences
END:VEVENT
END:VCALENDAR