This paper presents a new algorithm for the closed-loop H∞ composite control of singularly perturbed bilinear systems with time-varying parameter uncertainties and exogenous disturbance using the successive Galerkin approximation (SGA). The singularly perturbed bilinear system is decomposed into two subsystems of a slow-time scale and a fast-time scale via singular perturbation theory, and then...

in this paper, we consider the inhomogeneous time-fractional nonlinear fisher equation with three known boundary conditions. we first apply a modified homotopy perturbation method for translating the proposed problem to a set of linear problems. then we use the separation variables  method to solve obtained problems. in examples, we illustrate that by right choice of source term in the modified...

In a composite fluid system of two gravitationally coupled barotropic scale-free discs bearing a rotation curve v ∝ r and a power-law surface mass density Σ0 ∝ r −α with α = 1 + 2β, we construct coplanar stationary aligned and spiral perturbation configurations in the two discs. Due to the mutual gravitational interaction, there are two independent classes of perturbation modes with surface mas...

We show how some features of the AdS/CFT correspondence for AdS3 can easily be understood via standard world-sheet methods and 2d gravity like scaling arguments. To do this, we propose a stringy way for perturbing two-dimensional CFT’s around their critical points. Our strategy is to start from a stringy (world-sheet) representation of 2d CFT in space-time. Next we perturb a world-sheet action ...

We investigate the stability of inflating branes embedded in an O(2) texture formed in one extra dimension. The model contains two 3-branes of nonzero tension, and the extra dimension is compact. When the gravitational perturbation is applied, the vacuum energy which is responsible for inflation on the branes stabilizes the branes if the symmetry-breaking scale of the texture is smaller than so...

a. Introduction The primordial curvature perturbation ζ exists already a few Hubble times before the observable Universe enters the horizon. Its timeindependent value at that stage sets the initial condition for the subsequent evolution of all perturbations in the scalar and adiabatic mode, which in turn seem to the dominant (perhaps the only) cause of inhomogeneity in the Universe. The curvatu...