Bayesian versus robust control approach towards parameter uncertainty in monetary policymaking: how close are the outcomes? Some illustrating evidence from a pre-EMU economies.

International audienc

19F-N.M.R. study of F/O ordering in the trigonal Bi1−xPbxFxO1.5−x anionic conductor

International audienc

Quasi universal blast wave behavior

The two major parameters of shock wave propagation in free air are the space-time diagram and the decay of the peak overpressure as a function of the radial distance. This paper proposes a very simple mathematical function which simulates the space-time diagram and then correlates the peak overpressure. Various applications are presented that validate the proposed functions. In the far field, the asymptotic behaviour is consistent with the physical phenornenon and the similitude laws are preserved. In this manner, the quasi-universal behaviour of shock wave propagation in free air is demonstrated. Very easy-to-use, the proposed functions appear as quasi-universal ones

Application of data assimilation to three-dimensional hydrodynamics: the case of the Odra lagoon

Abstract. A data assimilation scheme enables to correct a model estimate, or rst-guess, of a physical state using measurements of the state variables. The best estimate is given by minimization of the estimation variance, as it is done in kriging. In sequential data assimilation, the spatial covariance of the rst-guess error is propagated forward in time using the physical model and requires only the knowledge of the model error (system noise). Since the data are often scarce in space, it is however a real scienti c challenge to assess its covariance structure. We present here an application to three-dimensional hydrodynamics, where a suboptimal lter is coupled with a numerical model solving the Navier-Stokes equations for shallow water. An original method for the construction of a spatial covariance from time series of water level measurements is introduced, making use of the physical properties of the system. The ltering has been applied to the simulation of water level in the Odra lagoon for the ood period of summer 1997. The method proves very e cient, despite a small number of assimilated measurements, and enables an improved reconstruction of the physical system. 1