PhD Thesis

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« Design of stochastic machines dedicated to bayesian inferences ».

Author: M. Faix
Advisor: E. Mazer
Co-advisor: L. Fesquet
thesis reviewer(s): B. Rouzeyre, P. Leray,
thesis examinator(s): O. Sentieys, W. Krauth, P. Galy, E. Alix,
These de Doctorat Université Grenoble Alpes
Speciality: Micro et Nano Electronique
Defense: December 12 2016
ISBN: 978-2-11-129223-9


The aim of this research is to design computers best suited to do probabilistic reasoning. The focus of the research is on the processing of uncertain data and on the computation of probabilistic distribution. For this, new machine architectures are presented. The concept they are built on is different to the one proposed by Von Neumann, without any fixed or floating point arithmetic. These architectures could replace the current processors in sensor processing and robotic fields. In this thesis, two types of probabilistic machines are presented. Their de-signs are radically different, but both are dedicated to Bayesian inferences and use stochastic computing. The first deals with small-dimension inference problems and uses stochastic computing to perform the necessary operations to calculate the inference. This machine is based on the concept of proba-bilistic bus and has a strong parallelism. The second machine can deal with intractable inference problems. It implements a particular MCMC method : the Gibbs algorithm at the binary level. In this case, stochastic computing is used for sampling the distribution of interest. An important feature of this machine is the ability to circumvent the convergence problems generally at-tributed to stochastic computing. Finally, an extension of this second type of machine is presented. It consists of a generic and programmable machine designed to approximate solution to any inference problem.

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