Square-root cubature Kalman filter (SCKF) is more effective for nonlinear state estimation than an unscented Kalman filter.In this paper,we study the design of nonlinear filters based on SCKF for the system with one step noise correlation and abrupt state change.First,we give the SCKF that deals with the one step correlation between process and measurement noises,SCKF-CN in short.Second,we introduce the idea of a strong tracking filter to construct the adaptive square-root factor of the prediction error covariance with a fading factor,which makes SCKF-CN obtain outstanding tracking performance to the system with target maneuver or abrupt state change.Accordingly,the tracking performance of SCKF is greatly improved.A universal nonlinear estimator is proposed,which can not only deal with the conventional nonlinear filter problem with high dimensionality and correlated noises,but also achieve an excellent strong tracking performance towards the abrupt change of target state.Three simulation examples with a bearings-only tracking system are illustrated to verify the efficiency of the proposed algorithms.
In recent years the evolution of olfactory bulb periglomerular cells,as well as the function of periglomerular cells in olfactory encoding,has attracted increasing attention.Studies of neural information encoding based on the analysis of simulation and modeling have given rise to electrophysiological models of periglomerular cells,which have an important role in the understanding of the biology of these cells.In this review we provide a brief introduction to the anatomy of the olfactory system and the cell types in the olfactory bulb.We elaborate on the latest progress in the study of the heterogeneity of periglomerular cells based on different classification criteria,such as molecular markers,structure,ion channels and action potentials.Then,we discuss the several existing electrophysiological models of periglomerular cells,and we highlight the problems and defects of these models.Finally,considering our present work,we propose a future direction for electrophysiological investigations of periglomerular cells and for the modeling of periglomerular cells and olfactory information encoding.
