Journal:Informatica
Volume 22, Issue 3 (2011), pp. 339–370
Abstract
This paper discusses the disease-free and endemic equilibrium points of a SVEIRS propagation disease model which potentially involves a regular constant vaccination. The positivity of such a model is also discussed as well as the boundedness of the total and partial populations. The model takes also into consideration the natural population growing and the mortality associate to the disease as well as the lost of immunity of newborns. It is assumed that there are two finite delays affecting to the susceptible, recovered, exposed and infected population dynamics.
Journal:Informatica
Volume 16, Issue 3 (2005), pp. 395–406
Abstract
This paper relates properties of operators with the well-known concepts of positive realness and passivity properties in dynamic systems and their associate transfer functions. Those concepts together with very close related ones are first examined from a physical point of view. Then, they are related with hyperstability and properties of transfer functions while the hyperstability theorem is revisited and interpreted. Finally, the above concepts are compared to the mathematical concepts of positivity and closely related ones in operator theory in Hilbert spaces.