Sampling-free linear Bayesian update of polynomial chaos representations

  • Authors:
  • Bojana V. Rosić;Alexander Litvinenko;Oliver Pajonk;Hermann G. Matthies

  • Affiliations:
  • Institute of Scientific Computing, TU Braunschweig, Hans-Sommer Straíe 65, 38106 Braunschweig, Germany;Institute of Scientific Computing, TU Braunschweig, Hans-Sommer Straíe 65, 38106 Braunschweig, Germany;Institute of Scientific Computing, TU Braunschweig, Hans-Sommer Straíe 65, 38106 Braunschweig, Germany;Institute of Scientific Computing, TU Braunschweig, Hans-Sommer Straíe 65, 38106 Braunschweig, Germany

  • Venue:
  • Journal of Computational Physics
  • Year:
  • 2012

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Abstract

We present a fully deterministic approach to a probabilistic interpretation of inverse problems in which unknown quantities are represented by random fields or processes, described by possibly non-Gaussian distributions. The description of the introduced random fields is given in a ''white noise'' framework, which enables us to solve the stochastic forward problem through Galerkin projection onto polynomial chaos. With the help of such a representation the probabilistic identification problem is cast in a polynomial chaos expansion setting and the Baye's linear form of updating. By introducing the Hermite algebra this becomes a direct, purely algebraic way of computing the posterior, which is comparatively inexpensive to evaluate. In addition, we show that the well-known Kalman filter is the low order part of this update. The proposed method is here tested on a stationary diffusion equation with prescribed source terms, characterised by an uncertain conductivity parameter which is then identified from limited and noisy data obtained by a measurement of the diffusing quantity.