In this paper we present nonlinear versions of the Circle and Popov Criteria of absolute asymptotic stability for nonlinear systems. We use a Kalman-Yakubovich-Popov type approach for nonlinear systems which involves a Hamilton-Jacobi equation and a nonlinear KYP system. Our criteria give su ciency conditions of absolute asymptotic stability as well as uniform estimations of the attraction basi...

Eremostachys pulvinaris (family: Labiatae), one of the 60 species of the genus Eremostachys, occurs mainly in central Asian countries, e.g. Iran, Armenia, Ashgabad and the USSR. The rhizomes of this plant were collected from Tabriz in Azarbaijan province during September-October 2003. There is no report on any previous phytochemical investigation on E. pulvinaris available todate, phytochemical...

The quantization of General Relativity invariant with respect to time-reparametrizations is considered. We construct the Faddeev-Popov generating functional for the unitary perturbation theory in terms of invariants of the kinemetric group of diffeomorphisms of a frame of reference as a set of Einstein’s observers with the equivalent Hamiltonian description (t = t(t), x = x(t, x, x, x)). The al...

We show that the computation of the Popov form of Ore polynomial matrices can be formulated as a problem of computing the left nullspace of such matrices. While this technique is already known for polynomial matrices, the extension to Ore polynomial matrices is not immediate because multiplication of the matrix entries is not commutative. A number of results for polynomial matrices are extended...

We show that the computation of the Popov form of Ore polynomial matrices can be formulated as a problem of computing the left nullspace of such matrices. While this technique is already known for polynomial matrices, the extension to Ore polynomial matrices is not immediate because multiplication of the matrix entries is not commutative. A number of results for polynomial matrices are extended...

This study analyzes the absolute stability in P and PD type fuzzy logic control systems with both certain and uncertain linear plants. Stability analysis includes the reference input, actuator gain and interval plant parameters. For certain linear plants, the stability (i.e. the stable equilibriums of error) in P and PD types is analyzed with the Popov or linearization methods under various ref...