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SUMMARY:Information Flows in Cooperative Networked Control Systems - Dr Gi
 rish Nair (University of Melbourne\, Australia)
DTSTART:20080304T140000Z
DTEND:20080304T150000Z
UID:TALK10474@talks.cam.ac.uk
CONTACT:Dr Guy-Bart Stan
DESCRIPTION:The control-theoretic equivalent of Ahlswede et. al's network 
 information theory is the problem of determining the rates at which inform
 ation must flow between system components in order to be able to cooperati
 vely achieve closed loop stability. This talk considers the case of a line
 ar\, time-invariant plant with multiple sensors and actuators that communi
 cate with each other over a network of directional digital channels with f
 inite bit rates. It is shown that\, under the stabilisation objective\, th
 e graph of the system possesses a structure that permits a fluid flow inte
 rpretation. A necessary and almost sufficient condition for determining un
 iform stabilisability is derived\, in terms of the feasibility of a set of
  linear inequalities in the unstable eigenvalues of the plant and the bit 
 rates of the channels. This provides an exact characterisation\, up to bou
 ndary points\, of the region of all stabilising channel bit rate vectors. 
 The auxiliary variables in this criterion have a natural interpretation as
  the effective rates of information flow associated with each unstable mod
 e. When channel rates are set to either zero or infinity\, this agrees wit
 h a classical result on decentralised stabilisability under linear\, time-
 varying control.
LOCATION: Cambridge University Engineering Department\, Lecture Room 4
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