We consider retarded time-delay systems ˙ x(t) = Ax(t) + Bx(t − τ), t > 0 x(t) = ϕ(t), t ∈ [−τ, 0] (Σ) where A, B ∈ R n×n .

We present new oscillation criteria for the second order nonlinear neutral delay differential equation ( a (t) (y (t)+ p (t) y (t − τ))′)′ + q (t) |y (σ (t))|α−1 y (σ (t)) = 0, where t ≥ t0, τ, and α are positive constants and the functions p, q, a, σ ∈ C ([t0,∞) ,R) . Our results generalize and improve some known results for oscillation of second order neutral delay differential equations. Our...

In this paper, the following third-order nonlinear delay differential equation with periodic coefficients x′′′(t) + p(t)x′′(t) + q(t)x′(t) + r(t)x(t) = f (t, x (t) , x(t− τ(t))) + c(t)x′(t− τ(t)), is considered. By employing Green’s function and Krasnoselskii’s fixed point theorem, we state and prove the existence of positive periodic solutions to the third-order delay differential equation.

In this paper, we investigate the use of N cognitive relays to assist primary and secondary transmissions in a timeslotted cognitive setting with one primary user (PU) and one secondary user (SU). We propose an overlapped spectrum sensing strategy for channel sensing, where the SU senses the channel for τ seconds from the beginning of the time slot and the cognitive relays sense the channel for...

The performance of nanoscale Field Effect Diodes as a function of the spacer length between two gates is investigated. Our numerical results show that the Ion/Ioff ratio which is a significant parameter in digital application can be varied from 101 to 104 for S-FED as the spacer length between two gates increases whereas this ratio is approximately constant for M-FED. The high-frequency perform...

In this paper, the following third-order nonlinear delay differential equation with periodic coefficients x′′′(t) + p(t)x′′(t) + q(t)x′(t) + r(t)x(t) = f (t, x (t) , x(t− τ(t))) + d dt g (t, x (t− τ (t))) , is considered. By employing Green’s function, Krasnoselskii’s fixed point theorem and the contraction mapping principle, we state and prove the existence and uniqueness of periodic solutions...

The second order nonlinear delay differential equation with periodic coefficients x ′′(t)+ p(t)x ′(t)+ q(t)x(t) = r(t)x ′(t − τ(t))+ f (t, x(t), x(t − τ(t))), t ∈ R is considered in this work. By using Krasnoselskii’s fixed point theorem and the contraction mapping principle, we establish some criteria for the existence and uniqueness of periodic solutions to the delay differential equation. c ...

The delay Lyapunov equation is an important matrix boundary-value problem which arises as an analogue of the Lyapunov equation in the study of time-delay systems ẋ(t) = A0x(t) +A1x(t− τ) +B0u(t). We propose a new algorithm for the solution of the delay Lyapunov equation. Our method is based on the fact that the delay Lyapunov equation can be expressed as a linear system of equations, whose unkn...

In this paper an approach to identify delay phenomena from time series is developed. We show that it is possible to perform a reliable time delay identification by using quantifiers derived from information theory, more precisely, permutation entropy and permutation statistical complexity. These quantifiers show clear extrema when the embedding delay τ of the symbolic reconstruction matches the...