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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Design And Implementation Of A Modified Communication Disturbance Observer For Teleoperation Systems, Zahra Zeinaly, Amin Ramezani, Sadjaad Ozgoli
Design And Implementation Of A Modified Communication Disturbance Observer For Teleoperation Systems, Zahra Zeinaly, Amin Ramezani, Sadjaad Ozgoli
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a novel structure for a communication disturbance observer in teleoperation systems is proposed to achieve robust stability. A time delay compensation method based on the concept of network disturbance and a communication disturbance observer (CDOB) has been proposed in past research. Unlike model-based approaches, it works without a time delay model. Therefore, it can be implemented in teleoperation systems with unknown and time-varying delay. However, it has been observed that the system model errors and external disturbances seriously affect the steady-state characteristics. Hence, in this paper, to achieve robustness against disturbance and model uncertainty, the structure of …
Concurrent Optimal Design Of Tcsc And Pss Using Symbiotic Organisms Search Algorithm, Muwaffaq Alomoush
Concurrent Optimal Design Of Tcsc And Pss Using Symbiotic Organisms Search Algorithm, Muwaffaq Alomoush
Turkish Journal of Electrical Engineering and Computer Sciences
The symbiotic organisms search (SOS), which has been recently introduced, is a robust powerful metaheuristic global optimizer. This nature-inspired algorithm imitates the symbiotic interaction strategies in an ecosystem exercised by organisms involved in interrelationships to survive and reproduce. One of the main beneficial features of the SOS in contrast to many other competent metaheuristic algorithms is that the algorithm does not need any specific algorithm parameters or tuning process. This paper applies the SOS algorithm to simultaneously design optimal controllers of a power system equipped with both a power system stabilizer (PSS) and a thyristor-controlled series compensator (TCSC). The algorithm …
$\Mathcal{Vw}$-Gorenstein Complexes, Renyu Zhao, Wei Ren
$\Mathcal{Vw}$-Gorenstein Complexes, Renyu Zhao, Wei Ren
Turkish Journal of Mathematics
Let $\mathcal{V,W}$ be two classes of modules. In this paper, we introduce and study $\mathcal{VW}$-Gorenstein complexes as a common generalization of $\mathcal{W}$-complexes, Gorenstein projective (resp., Gorenstein injective) complexes, and $G_C$-projective (resp., $G_C$-injective) complexes. It is shown that under certain hypotheses a complex $X$ is $\mathcal{VW}$-Gorenstein if and only if each $X^n$ is a $\mathcal{VW}$-Gorenstein module. This result unifies the corresponding results of the aforementioned complexes. As an application, the stability of $\mathcal{VW}$-Gorenstein complexes is explored.
Stability Of Nonmonotone Critical Traveling Waves Forspatially Discrete Reaction-Diffusion Equations With Time Delay, Ge Tian, Guobao Zhang, Zhao-Xing Yang
Stability Of Nonmonotone Critical Traveling Waves Forspatially Discrete Reaction-Diffusion Equations With Time Delay, Ge Tian, Guobao Zhang, Zhao-Xing Yang
Turkish Journal of Mathematics
This paper is concerned with the existence and stability of critical traveling waves (waves with minimal speed $c=c_*$) for a nonmonotone spatially discrete reaction-diffusion equation with time delay. We first show the existence of critical traveling waves by a limiting argument. Then, using the technical weighted energy method with some new variations, we prove that the critical traveling waves $\phi(x+c_{*}t)$ (monotone or nonmonotone) are time-asymptotically stable when the initial perturbations are small in a certain weighted Sobolev norm.
Temporal Preconditioners For Marching-On-In-Time-Based Time Domain Integral Equation Solvers, Hüseyi̇n Arda Ülkü
Temporal Preconditioners For Marching-On-In-Time-Based Time Domain Integral Equation Solvers, Hüseyi̇n Arda Ülkü
Turkish Journal of Electrical Engineering and Computer Sciences
Temporal preconditioners to stabilize the marching-on-in-time (MOT)-based time domain integral equation (TDIE) solvers are proposed. Exponentially decaying functions are used as temporal preconditioners and the proposed scheme is applied to analyze scattering from perfect electrically conducting objects using the second-order formulation. The effectiveness of the proposed scheme is demonstrated via numerical examples. It is shown that the temporal preconditioners stabilize the MOT system and the solution. In addition, the initial condition problem of TDIEs is investigated by extending the second-order formulation of the time domain electric field integral equation to the time domain magnetic and combined field integral equations.
Near Optimal Step Size And Momentum In Gradient Descent For Quadratic Functions, Engi̇n Taş, Memmedağa Memmedli̇
Near Optimal Step Size And Momentum In Gradient Descent For Quadratic Functions, Engi̇n Taş, Memmedağa Memmedli̇
Turkish Journal of Mathematics
Many problems in statistical estimation, classification, and regression can be cast as optimization problems. Gradient descent, which is one of the simplest and easy to implement multivariate optimization techniques, lies at the heart of many powerful classes of optimization methods. However, its major disadvantage is the slower rate of convergence with respect to the other more sophisticated algorithms. In order to improve the convergence speed of gradient descent, we simultaneously determine near-optimal scalar step size and momentum factor for gradient descent in a deterministic quadratic bowl from the largest and smallest eigenvalues of the Hessian. The resulting algorithm is demonstrated …
Stability Analysis Of Nonlinear Fractional Differential Order Systems With Caputo And Riemann--Liouville Derivatives, Javad Alidousti, Reza Khoshsiar Ghaziani, Ali Bayati Eshkaftaki
Stability Analysis Of Nonlinear Fractional Differential Order Systems With Caputo And Riemann--Liouville Derivatives, Javad Alidousti, Reza Khoshsiar Ghaziani, Ali Bayati Eshkaftaki
Turkish Journal of Mathematics
In this paper we establish stability theorems for nonlinear fractional orders systems (FDEs) with Caputo and Riemann--Liouville derivatives. In particular, we derive conditions for $ {\bf \cal{F}}$-stability of nonlinear FDEs. By numerical simulations, we verify numerically our theoretical results on a test example.