On the Solution of the Eigenvalue Assignment Problem for Discrete-Time Systems
Journal ArticleTe output feedback eigenvalue assignment problem for discrete-time systems is considered. Te problem is formulated frst as
an unconstrained minimization problem, where a three-term nonlinear conjugate gradient method is proposed to fnd a local
solution. In addition, a cut to the objective function is included, yielding an inequality constrained minimization problem, where a
logarithmic barrier method is proposed for fnding the local solution. Te conjugate gradient method is further extended to tackle
the eigenvalue assignment problem for the two cases of decentralized control systems and control systems with time delay. Te
performance of the methods is illustrated through various test examples.
Fatma Farag Said Omar, El-Sayed M. E. Mostafa, Abdallah W. Aboutahoun,, (08-2017), Journal of Applied Mathematics: تم أختياره, 2017 (1), 1-13
Logistic Growth with a Slowly Varying Holling Type II Harvesting Term
Journal ArticleThe Holling type II harvesting term has the property that it is small for small population values, but grows monotonically with population growth, eventually saturating, at a constant value for very large populations. We consider here a population evolving according to a logistic rate, but harvested (predated) subject to a Holling type II harvesting term that varies slowly with time, possibly due to slow environmental variation. Application of a multitiming method gives us an approximation to the population at any time in two cases- survival to a slowly varying limit, and extinguishment to zero. The situation where there is a transition from survival to extinction is also analyzed, using a matched expansions approach. A uniformly valid approximate expression for the population, valid for all times is obtained. These results are shown to agree well with the results of numerical calculations.
Majda Ashor Mohammad Idlango, John .J. Shepherd, (02-2017), Communications in Nonlinear Science and Numerical Simulation: ELSEVIER, 49 (1), 1-7
Some Results on Differential Subordination Defined by a Generalized Derivative Operator
Journal ArticleThe object of the present paper is to derive some results on differential subordination associated with a generalized derivative operator for certain normalized analytic functions in the open unit disc. The authors establish sandwich type theorems. These results extend many previously known results.
Entisar EL-Yagubi, (01-2016), Tokyo: International Information Institute, 19 (1), 7-15
ON A SUBCLASS OF P-VALENT STARLIKE FUNCTIONS ASSOCIATED WITH A GENERALIZED HYPERGEOMETRIC DIFFERENTIAL OPERATOR
Conference paperThe object of the present paper is to introduce a new subclass of p-valent starlike functions with negative coefficients in the open unit disc which is defiined by a generalized derivative operator. We obtain coefficient inequalities, growth and distortion theorems and extreme points for the subclass of p-valent functions.
Entisar EL-Yagubi, (11-2015), TURKISH: New Developments In Pure and Applied Mathematics, 159-162
BAZILEVIČ P-VALENT FUNCTIONS ASSOCIATED WITH GENERALIZED HYPERGEOMETRIC FUNCTIONS
Journal ArticleThe aim of this paper is to introduce and study a new class of Bazilevič p-valent function of order β by using the subordination concept between this function and a generalized derivative operator. Some interesting properties are also obtained
Entisar EL-Yagubi, (08-2015), University Library in Kragujevac: Kragujevac Journal of Mathematics, 39 (1), 111-120
On certain classes of fractional p-valent analytic functions
Journal ArticleThe theory of analytic functions and more specific p-valent functions, is one of the most fascinating topics in one complex variable. There are many remarkable theorems dealing with extremal problems for a class of p-valent functions on the unit disk U. Recently, many researchers have shown great interests in the study of differential operator. The objective of this paper is to define a new generalized derivative operator of p-valent analytic functions of fractional power in the open unit disk U. This operator generalized some well-known operators studied earlier, we mention some of them in the present paper. Motivation by the generalized derivative operator; we introduce and investigate two new subclasses of starlike p-valent analytic functions of fractional power with positive coefficients and starlike p-valent analytic functions of fractional power with negative coefficients, respectively. In addition, a sufficient condition will be obtained. Some corollaries are also pointed out. Moreover, we determine the extreme points of functions belong to the class.
Entisar EL-Yagubi, (07-2015), -: Izvestiya Journal, 11 (1), 28-38
on certain subclasses of harmonic univalent functions with respect to k- symmetric points
Journal ArticleThe aim of the article is to study a sufficient condition for the classes of starlike and convex harmonic univalent functions with respect to k- symmetric points. The necessary condition for f to be in the classes will be studied. In addition, growth bounds for functions will also be given.
Entisar EL-Yagubi, (05-2015), Tokyo: International Information Institute, 18 (5), 1509-1520
A STUDY ON A CLASS OF P-VALENT FUNCTIONS ASSOCIATED WITH GENERALIZED HYPERGEOMETRIC FUNCTIONS
Journal ArticleIn this paper, we study and introduce the majorization properties of a new class of analytic p-valent functions of complex order defined by the generalized hypergeometric function. Some known consequences of our main result will be given. Moreover, we investigate the coefficient
estimates for this class.
Entisar EL-Yagubi, (04-2015), -: Vladikavkaz Mathematical Journal, 17 (1), 31-38
SOME PROPERTIES OF DIFFERENTIAL OPERATOR ASSOCIATED WITH GENERALIZED HYPERGEOMETRIC FUNCTIONS
Journal ArticleIn the present investigation, new subclasses of analytic functions in the open unit disk which are defined using generalized derivative operator are introduced. Several interesting properties of these classes are obtained.
Entisar EL-Yagubi, (03-2015), -: Tamkang Journal of Mathematics, 46 (1), 75-83
On the multiscale approximation of solutions to the slowly varying harvested logistic population model
Journal ArticleWe provide a validation of a formal approximate solution to the problem of the evolution of a slowly varying harvested logistic population. Using a contraction mapping proof, we show that the initial value problem for the population has an exact solution lying in an appropriately small neighbourhood of this approximate solution, under quite general conditions.
Majda A. Idlango, (01-2015), Communications in Nonlinear Science and Numerical Simulation: ELSEVIER, 26 (3), 36-44