Brian S Guidry

US Patent:

20060098746, May 11, 2006

Filed:

Nov 10, 2005

Appl. No.:

11/271334

Inventors:

James Candy - Danville CA, US
David Chambers - Livermore CA, US
Brian Guidry - Tracy CA, US
Andrew Poggio - Livermore CA, US
Christopher Robbins - Livermore CA, US

International Classification:

H04L 27/00

US Classification:

375259000

Abstract:

A communication system for transmitting a signal through a channel medium comprising digitizing the signal, time-reversing the digitized signal, and transmitting the signal through the channel medium. In one embodiment a transmitter is adapted to transmit the signal, a multiplicity of receivers are adapted to receive the signal, a digitizer digitizes the signal, and a time-reversal signal processor is adapted to time-reverse the digitized signal. An embodiment of the present invention includes multi bit implementations. Another embodiment of the present invention includes 1-bit implementations. Another embodiment of the present invention includes a multiplicity of receivers used in the step of transmitting the signal through the channel medium.

US Patent:

20100030721, Feb 4, 2010

Filed:

Oct 27, 2008

Appl. No.:

12/259198

Inventors:

James V. Candy - Danville CA, US
Michael C. Axelrod - San Ramon CA, US
Eric F. Breitfeller - Dublin CA, US
David H. Chambers - Livermore CA, US
Brian L. Guidry - Livermore CA, US
Douglas R. Manatt - Livermore CA, US
Alan W. Meyer - Danville CA, US
Kenneth E. Sale - Castro Valley CA, US

International Classification:

G06N 5/02

US Classification:

706 52

Abstract:

A distributed sequential method and system for detecting and identifying radioactive contraband from highly uncertain (noisy) low-count, radionuclide measurements, i.e. an event mode sequence (EMS), using a statistical approach based on Bayesian inference and physics-model-based signal processing based on the representation of a radionuclide as a monoenergetic decomposition of monoenergetic sources. For a given photon event of the EMS, the appropriate monoenergy processing channel is determined using a confidence interval condition-based discriminator for the energy amplitude and interarrival time. If accepted the parameter values of the photon event are used to update the parameter values using an LKF for the energy amplitude and a bootstrap PF for the interarrival times. These parameter estimates are then used to update a measured probability density function estimate for a target radionuclide. A a sequential likelihood ratio test, which is based in part on a previous sequential likelihood ratio for a previous photon event, the updated measured PDF estimates, and the an a-priori PDF estimates based on expected amplitude level and interarrival time values of the target radionuclide, is then used to determine one of two threshold conditions signifying that the EMS is either identified as the target radionuclide or as not the target radionuclide, and if not, then repeating the process with for the next sequential photon event of the EMS until one of the two threshold conditions is satisfied.