Fluctuations and Correlations in Nucleus-Nucleus Collisions within Transport Models

Particle number fluctuations and correlations in nucleus-nucleus collisions at SPS and RHIC energies are studied within microscopic transport approaches. In this review we focus on the Hadron-String-Dynamics (HSD) and Ultra-relativistic-Quantum-Molecular-Dynamics (UrQMD) models The obtained results are compared with the available experimental data as well as with the statistical models and the model of independent sources. In particular the role of the experimental centrality selection and acceptance is discussed in detail for a variety of experimental fluctuations and correlation observables with the aim to extract information on the critical point in the $(T,\mu_B)$ plane of strongly interacting matter.