Wafa Shammakh
King Abdulaziz University
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Publication
Featured researches published by Wafa Shammakh.
Neurocomputing | 2015
Xunyuan Yin; Zhaojian Li; Lixian Zhang; Changhong Wang; Wafa Shammakh; Bashir Ahmad
In this paper, the problem of H ∞ model reduction for a class of discrete-time Markov jump nonlinear systems with time-varying delays is investigated. Based on the Lyapunov-Krasovskii functional method, sufficient stability conditions in terms of strict LMIs are derived for the model error system. Projection approach is employed to construct a reduced-order model such that the model error system is asymptotically stable and preserves a guaranteed H ∞ performance. A numerical example is presented to illustrate the effectiveness of the developed theoretical results and to make comparisons among systems with different structures and parameters.
Journal of Function Spaces and Applications | 2015
H. Batarfi; Jorge Losada; Juan J. Nieto; Wafa Shammakh
We study a fractional differential equation using a recent novel concept of fractional derivative with initial and three-point boundary conditions. We first obtain Greens function for the linear problem and then we study the nonlinear differential equation.
Mathematical Problems in Engineering | 2014
Hamed Al-Sulami; Moustafa El-Shahed; Juan J. Nieto; Wafa Shammakh
This paper deals with the fractional order dengue epidemic model. The stability of disease-free and positive fixed points is studied. Adams-Bashforth-Moulton algorithm has been used to solve and simulate the system of differential equations.
Neurocomputing | 2015
Yanzheng Zhu; Lixian Zhang; Zepeng Ning; Zhenzong Zhu; Wafa Shammakh; Tasawar Hayat
This paper focuses on the state estimation problem for a class of discrete-time switching neural networks with persistent dwell time (PDT) switching regularities and mode-dependent time-varying delays in H ∞ sense. The considered switching regularity is more general that extends the frequently studied dwell-time (DT) and average dwell-time (ADT) switching. The random packet dropouts, which are governed by a Bernoulli distributed white sequence, are considered to exist together for the estimator design of underlying switching neural networks. The desired mode-dependent estimators are designed such that the resulting estimation error system is exponentially mean-square stable and achieves a prescribed H ∞ level of disturbance attenuation. Finally, the effectiveness and the superiority of the developed results are demonstrated through a class of synthetic oscillatory networks.
Abstract and Applied Analysis | 2013
Lihong Zhang; Bashir Ahmad; Guotao Wang; Ravi P. Agarwal; Maryem Al-Yami; Wafa Shammakh
This paper investigates the existence of nonnegative solutions for nonlinear fractional differential equations with nonlocal fractional integrodifferential boundary conditions on an unbounded domain by means of Leray-Schauder nonlinear alternative theorem. An example is discussed for the illustration of the main work.
International Journal of Systems Science | 2016
Yanzheng Zhu; Lixian Zhang; Victor Sreeram; Wafa Shammakh; Bashir Ahmad
ABSTRACT In this paper, the resilient model approximation problem for a class of discrete-time Markov jump time-delay systems with input sector-bounded nonlinearities is investigated. A linearised reduced-order model is determined with mode changes subject to domination by a hierarchical Markov chain containing two different nonhomogeneous Markov chains. Hence, the reduced-order model obtained not only reflects the dependence of the original systems but also model external influence that is related to the mode changes of the original system. Sufficient conditions formulated in terms of bilinear matrix inequalities for the existence of such models are established, such that the resulting error system is stochastically stable and has a guaranteed l2-l∞ error performance. A linear matrix inequalities optimisation coupled with line search is exploited to solve for the corresponding reduced-order systems. The potential and effectiveness of the developed theoretical results are demonstrated via a numerical example.
Abstract and Applied Analysis | 2015
Wafa Shammakh; Maryam Al-Yami
The problem of positive solutions for nonlinear -fractional difference eigenvalue problem with nonlocal boundary conditions is investigated. Based on the fixed point index theory in cones, sufficient existence of positive solutions conditions is derived for the problem.
Journal of Function Spaces and Applications | 2016
Wafa Shammakh
Existence and uniqueness results of positive solutions to nonlinear boundary value problems for Caputo-Hadamard fractional differential equations by using some fixed point theorems are presented. The related Green’s function for the boundary value problem is given, and some useful properties of Green’s function are obtained. Example is presented to illustrate the main results.
International Journal of Machine Learning and Cybernetics | 2016
Saleem Abdullah; Wafa Shammakh; Tahir Mahmood; Muhammad Shahzad
AbstractThe aim of this article, we combine the fuzzy soft set and fuzzy topological space. We introduce the notion of fuzzy soft set over common universe of fuzzy topological space. We defined quasi-open fuzzy soft set over fuzzy topological space and we study the properties of extended union of two quasi-open fuzzy soft set over fuzzy topological space. We study “OR” and “AND” operations of quasi-open fuzzy soft set over fuzzy topological space. We also define open fuzzy soft set, b-open fuzzy soft set and b-closed fuzzy soft set over fuzzy topological space. We give some characterizations of these concepts.
Carbon | 2016
Guodong Sheng; Ahmed Alsaedi; Wafa Shammakh; Shatha Monaquel; Jiang Sheng; Xiangke Wang; Hui Li; Yuying Huang