Ricerc@Sapienza

In this paper, the problem of stabilizing linear port-controlled Hamiltonian dynamics through interconnection and damping assignment in presence of input delays is considered. The contribution exploits the reduction approach allowing to reveal and shape the energy properties of the time-delay dynamics. Performances are illustrated on a simple mechanical system.

In this paper, a new model describing the human immunodeficiency virus (HIV)-acquired immuno deficiency syndrome (AIDS) epidemic spread is proposed. The improvement with respect to the known models has been driven by recent results obtained from historical data collection and the suggestions given by the World Health Organization: the characteristics of the virus diffusion, mainly by body fluids, imply the trivial fact that wise behaviors of healthy subjects and fast timely recognition of a new positive diagnosis should reduce the spread quite fast.

An optimized system management of a commercial and industrial power system must take care of the actual operational and energetic duty of the power system distribution. A procedure based on the Arrhenius model of the Thermal Aging of Insulating Materials allows introducing the relative time coefficient (RTC) and promoting a heuristic method, as a rule of thumb, to estimate the life loss and the residual useful life for insulated power cables.

An improved second order artificial material single layer (AMSL) method is proposed to predict the electromagnetic field in presence of conductive thin layers by the finite element method (FEM). The AMSL method is based on the replacement of the material physical constants of a conductive shield region with those of an artificial material. The new AMSL physical constants are analytically extracted by equating the equivalent transmission line (TL) equations governing the field propagation inside the shield with the FEM solution.

The Frisch-Waugh-Lovell (FWL) Recursive Least Squares (RLS) algorithm has been recently proposed as an RLS algorithm with lower computational cost and better numerical properties. We propose a VHDL implementation that has been successfully implemented on a Xilinx Virtex-7 FPGA. The FWL RLS algorithm has a complexity of L2 + O(L) products, instead of 1.5L2 O(L) as in conventional RLS algorithms. Because it removes all matrix operations, separating an L input vector problem into L separate scalar problems, it is stable and often faster in fixed-point arithmetic than conventional RLS.