Jonas Ströjby Modelling non-linear stochastic dynamic systems with recurrent neural networks and non-linear filters with applications in energy trading Abstract: In this Masters project we study time series modeling and forecasting by using non-linear Kalman filters and recurrent neural networks. Neural networks are universal approximators and the inclusion of internal recurrence allow for temporal structures and memory. They are used to approximate the dynamics of the studied system. The parameters of the neural network are estimated using non-linear Kalman filters. The noise on both output and input is studied and handled. A method to handle noisy inputs based on the unscented Kalman filter is presented. Also, an approximative method to estimate conditional variance is suggested. We present a couple of synthetic examples intended to show various properties of the method and also show it's performance on two real applications relevant in energy trading.