This article details the main concepts, problems and applications related to state-space models. We first present the general framework for these models and we, then, make explicit the algorithms used for the estimation, i.e. the Kalman filter and the EM algorithm. We, finally, analyse four...

[eng] The retirements of Europe Alexis Dantec and Florian Pelgrin The subsidiarity principle states that a decision should not be taken at the Community level if it does not better the one taken at the national level. The retirement is one of the most controversial economic and politic issue....