In this paper we derive a necessary and sufficient condition for the existence of a common diagonal quadratic Lyapunov function for a pair of positive linear time-invariant (LTI) systems.

This letter considers the problem of linear time-invariant (LTI) system identification using input/output data. Recent work has provided non-asymptotic results on partially observed LTI a single trajectory but is only suitable for stable systems. We provide finite-time analysis learning Markov parameters based ordinary least-squares (OLS) estimator multiple trajectories, which covers both and u...

In this work, we introduce a novel data-driven formulation, the Koopman-Linearly-Time-Invariant (Koopman-LTI) analysis, for analyzing Fluid-Structure Interactions (FSI). An implementation of Koopman-LTI on subcritical free-shear flow over prism at Re=22,000 corroborated configuration-wise universal Koopman system, which approximated configuration's nonlinear dynamics with stellar accuracy. The ...

We extend two fundamental properties of positive linear time-invariant (LTI) systems to homogeneous cooperative systems. Specifically, we demonstrate that such systems are D-stable, meaning that global asymptotic stability is preserved under diagonal scaling. We also show that a delayed homogeneous cooperative system is globally asymptotically stable (GAS) for any non-negative delay if and only...

In this paper, the Linear Time Invariant (LTI) and Periodic (LTP) models of two different implementations DDSRF-PLL in presence voltage imbalance are derived analytically. The accuracy is investigated with time domain simulations, frequency scans, stability analysis. On top this, a guideline for properly choosing between LTI LTP assessment according to degree grid proposed. Furthermore, it reve...

Many systems can be approximated as linear with coefficients that vary periodically with time. For example, an anisotropic shaft rotating at constant speed on anisotropic bearings can be modeled as periodically time varying (PTV). Similar models can be obtained for wind turbines, some mechanisms, etc... However, the vast majority of modal analysis algorithms and techniques apply only to linear ...

The authors construct a class of elementary nonparametric output predictors of an unknown discrete-time nonlinear fading memory system. Their algorithms predict asymptotically well for every bounded input sequence, every disturbance sequence in certain classes, and every linear or nonlinear system that is continuous and asymptotically time-invariant, causal, and with fading memory. The predicto...

We consider the decidability of state-to-state reachability in linear time-invariant control systems, with control sets defined by boolean combinations of linear inequalities. Decidability of the sub-problem in which control sets are linear subspaces is a fundamental result in control theory. We first show that reachability is undecidable if the set of controls is a finite union of affine subsp...

This paper investigates issues in modeling of currentmode control. The effects of the current-sampling intrinsic to current-mode control are analyzed, and inadequately recognized limitations of linear time-invariant (LTI) models at high frequencies (where the system behavior is time-varying) are exposed. The paper also examines the geometric methods used to derive dutyratio constraints in avera...

In this paper, a hybrid controller design for a continuous-time linear time-invariant (LTI) plant is presented. The idea is to simultaneously design the flow and jump maps with the respective sets of the controller, guaranteeing H∞ specifications and decay rate of the plant state of the hybrid closed-loop system. A convex LMI-based design procedure is proposed, generalizing the results in [22].