This paper proposes a new simple model to forecast daily global solar irradiation one day ahead using the Takagi-Sugeno fuzzy methods. The model is based on solar radiation data measured in Timisoara, Romania. The daily clearness index represents the direct variable used by the fuzzy algorithm. The model forecasts the clearness index at the moment of time t on basis of two previous values measured at time t-1 and t-2. An assessment of the model accuracy is performed.
The article presents some new aspects and experience on the use of computer in teaching general relativity and cosmology for undergraduate students (and not only) with some experience in computer manipulation. Some years ago certain results were reported  using old fashioned computer algebra platforms but the growing popularity of graphical platforms as Maple and Mathematica forced us to adapt and reconsider our methods and programs. We will describe some simple algebraic programming procedures (in Maple with GrTensorII package) for obtaining and the study of some exact solutions of the Einstein equations in order to convince a dedicated student in general relativity about the utility of a computer algebra system.