Exterior algebra and invariant spaces of implicit systems: The Grassmann representative approach
External properness
In this paper, we revisit the structural concept of properness. We distinguish between the properness of the whole system, here called internal properness, and the properness of the “observable part” of the system. We give geometric characterizations for this last properness concept, namely external properness.
External reachability (reachability with pole assignment by p. d. feedback) for implicit descriptions
Externally and internally positive singular discrete-time linear systems
Notions of externally and internally positive singular discrete-time linear systems are introduced. It is shown that a singular discrete-time linear system is externally positive if and only if its impulse response matrix is non-negative. Sufficient conditions are established under which a single-output singular discrete-time system with matrices in canonical forms is internally positive. It is shown that if a singular system is weakly positive (all matrices E, A, B, C are non-negative), then it...
Externally and internally positive time-varying linear systems
The notions of externally and internally positive time-varying linear systems are introduced. Necessary and sufficient conditions for the external and internal positivities of time-varying linear systems are established. Moreover, sufficient conditions for the reachability of internally positive time-varying linear systems are presented.
Extinction in nonautonomous discrete Lotka-Volterra competitive system with pure delays and feedback controls.
Extracting second-order structures from single-input state-space models: Application to model order reduction
This paper focuses on the model order reduction problem of second-order form models. The aim is to provide a reduction procedure which guarantees the preservation of the physical structural conditions of second-order form models. To solve this problem, a new approach has been developed to transform a second-order form model from a state-space realization which ensures the preservation of the structural conditions. This new approach is designed for controllable single-input state-space realizations...