Samir H. Saker

Born: Junuary 11, 1971.

place: Egypt

B. Sc. (1993) Mathematics Mansoura University, Egypt; M. Sc. (1997) Mathematics (Differential Equations), Mansoura University, Egypt..

Ph. D. (Decmber 2002) in Mathematics, Adam Mickiewicz University, Poznan, Poland

thesis:: Oscillation Theory of Delay Differential and Difference Equations and Some of Their Applications;Trinity University, San Antonio, TX March 2005 to August 2005 and in Canada, University of Calgary August 2005 to August 2006.

personal or universal URL:

http://www.mans.edu.eg/pcvs/30040.asp

email: shsaker@mans.edu.eg OR shsaker@trinity.eduEmployment History

Lecturer of Mathematics, Department of Mathematics, Faculty of Science, Mansoura University from 20/7/2003 till Now.

Assistant Lecturer of Mathematics, Department of Mathematics, Faculty of Science, Mansoura University from 17/1/98 to 19/7/2003.

Demonstrator of Mathematics, Department of Mathematics, Faculty of Science, Mansoura University from 17/12/1994 to 16/1/1998.

RESEARCH

**Summary of Studies:**

- Oscillation theory of differential and partial differential equations
- Oscillation theory of difference and partial difference equations,
- Periodicity of non-autonomous delay difference equations,
- Global dynamics of nonlinear delay continuous and discrete mathematical models in Biology, Ecology, Medicines, Economics, etc. (oscillation, boundedness, permanence, periodicity, persistence, stability, global attractivity).
- Oscillation theory of dynamic equations on time scales.

P

UBLICATIONS

- S. H. Saker and J. V. Manojlovic, Oscillation criteria for second order Superlinear neutral delay differential equations, EJQTDE. 10 (2004), 1-22.
- S. H. Saker, Oscillation criteria of certain class of third-order nonlinear delay differential equations, Math. Slovaca (accepted).
- S. H. Saker, Oscillation of second order neutral delay differential equations of Emden-Fowler type, Acta Math. Hungarica 100, no.1-2 (2003), 7-32.
- E. M. Elabbasy and S. H. Saker, Oscillation of delay differential equations with several positive and negative coefficients, Disc. Math. Differential Inclusion, (23) (2003) 39-52.
- S. H. Saker, P.Y.H. Pang and Ravi P Agarwal, Oscillation theorems for second order nonlinear functional differential equations with damping, Dynamic Sys. Appl. 12 (2003), 307-322.
- I. Kubiaczyk and S. H. Saker and J. Morhalo, New oscillation criteria for nonlinear neutral delay differential equations, Appl. Math. Comp. 142 (2-3)(2003), 225-242.
- S. H. Saker, Oscillation of solutions of a pair of coupled nonlinear delay differential equations, Portugalae Mathematica 60 (2003), 319-336.
- I. Kubiaczyk, W. T. Li and S. H. Saker, Oscillation of higher order delay differential equations with applications to hyperbolic equations, Indian J. Pure & Appl. Math. 34 (2003), 1259-1271.
- S. H. Saker, Oscillation of higher order
neutral delay differential equations with variable coefficients,
Dynamic Systems & Application
**11**(2002), no. 1, 107-125. - I. Kubiaczk and S. H. Saker, New oscillation criteria of first order delay differential equations, Demonstr. Math. 35, no.2 (2002), 313-324.
- W. T. Li and S. H. Saker, Oscillation of solutions to impulsive delay differential equations, Commentationes Mathematicae XLII (2002), 63-74.
- I. Kubiaczyk, S. H. Saker, Oscillation of solution of neutral delay differential equations, Math. Slovaca 52 (2002), no. 3, 343-359.
- S. H. Saker and I. Kubiaczyk, Oscillation of nonlinear neutral delay differential equations, J. Appl. Analysis 8 (2002), no.2, 261-278.
- I. Kubiaczyk and S. H. Saker, Oscillation
theorems of second order nonlinear neutral delay differential
equations, Disc. Math. Diff. Incl. Cont. Optim.
**22**(2002), 185-212. - Ravi P. Agarwal and S. H. Saker, Oscillation of solutions to neutral delay differential equations with positive and negative coefficients, International Journal of Differential Equations and Applications 2 (2001), 449-465.
- S. H. Saker and E. M. Elabbasy, Oscillation of first order neutral delay differential equations, Kyungpook Mathematical Journal 41 (2001), 311-321.
- W. T. Li and S. H. Saker, Oscillation of
nonlinear neutral delay differential equations and applications,
Annales Polinici Mathematici
**77**(2001), no. 1, 39-51. - E. M. Elabbasy, A. S. Hegazi and S. H. Saker, Oscillation of solutions to delay differential equations with positive and negative coefficients, Electronic Journal of Differential Equations 2000, No. 13 (2000), 1-13.
- E. M. Elabbasy and S. H. Saker, Oscillation of nonlinear delay differential equations with several positive and negative coefficients, Kyungpook Mathematical Journal, Vol. 39 (1999), 366-376.
- E. M. Elabbasy, S. H. Saker and K. Saif, Oscillation of nonlinear delay differential equations with application to models exhibiting the Allee effect, Far East Journal of Mathematical Sciences, Vol. 1, no. 4 (1999), 603-620.

**Partial Differential Equations**

- I. Kubiaczyk, S. H. Saker, Oscillation of parabolic delay differential equations, Demonst. Math. 35, no.4 (2002), 781-792.
- I. Kubiaczyk and S. H. Saker, Oscillation of delay parabolic differential equations with several coefficients, J. Comp. Appl. Math. 147 (2002), no. 2, 263-275.
- I. Kubiaczyk and S. H. Saker, Oscillation of parabolic delay differential equations with positive and negative coefficients, Commentationes Mathematicae XLII (2002), 221-236.
- S. H. Saker, Oscillation of hyperbolic nonlinear differential equations with deviating arguments, Publ. Math. Debr. 62 (2003), 165-185.

**Difference Equations**

- Y. G. Sun and S. H. Saker, Oscillation for second-order nonlinear neutral delay difference equations, Appl. Math. Comp. 163 (2005) 909-918.
- S. H. Saker, Oscillation criteria of second-order half-linear delay difference equations, Kyungpook Math. J. (accepted).
- S. H. Saker, Oscillation and asymptotic behavior of third-order nonlinear neutral delay difference equations, Dynamic Systems & Applications, (accepted).
- S. H. Saker, Oscillation of third-order difference equations, Portugalae Mathematica 61 (2004), 249-257.
- I. Kubiaczyk and S. H. Saker, Oscillation
and asymptotic behavior of second-order nonlinear difference
equations,
*Fasc. Math.*No. 34 (2004), 39-54. - S. H. Saker and S. S. Cheng, Kamenev type
oscillation criteria for nonlinear difference equations, Czechoslovak
Math. J. 54 (2004) 955 967
**.** - S. H. Saker and S. S. Cheng, Oscillation criteria for difference equations with damping terms, Appl. Math. Comp. 148 (2004), 421-442.
- S. H. Saker, Oscillation of second order nonlinear delay difference equations, Bulletin of the Korean Math. Soc. 40 (2003), 489-501.
- S. H. Saker, Oscillation theorems for second-order nonlinear delay difference equations, Periodica Math. Hungarica 47 (2003), 201-213.
- B. G. Zhang and S. H. Saker, Kamenev-Type
Oscillation Criteria for Nonlinear Neutral Delay Difference ,
Indian J. Pure Appl. Math
**34**(2003), 1571-1584. - I. Kubiaczyk, S. H. Saker, J. Morchalo, Kamenev-type
oscillation criteria for sublinear delay difference equations,
Indian J. Pure Appl. Math.
**34**(2003), 273-1284. - S. H. Saker, New oscillation criteria for second-order nonlinear neutral delay difference equations, Appl. Math. Comp. 142 (1)(2003), 99-111.
- S. H. Saker, Oscillation theorems of nonlinear difference equations of second order, Georgian Mathematical J. 10, no.2 (2003), 343-352.
- S. H. Saker, Oscillation of second-order perturbed nonlinear difference equations, Appl. Math. Comp. 144 (2-3) (2003), 305-324.
- W. T. Li and S. H. Saker, Oscillation of second-order sublinear neutral delay difference equations, Appl. Math. Comp. 146 (2003), 543-551
- S. H. Saker and P. J. Y. Wong, Nonexistence of unbounded nonoscillatory solutions of nonlinear perturbed partial difference equations, J. Concrete and Aapplicable Math. 1 (1) (2003), 87-99.
- S. H. Saker, Oscillation of nonlinear neutral difference equations, Inter. J. Pure Appl. Math. vol. 1, no. 4 (2002), 459-470.
- S. H. Saker, Kamenev-type oscillation criteria for forced Emden-Fowler Superlinear difference equations, Elect. J. Diff. Eqns. 2002 (2002), no. 68, 1-9.

**Partial Difference Equations**

- S. H. Saker, Oscillation of parabolic neutral delay difference equations, Bull. Korean Math. Soc. (to appear).
- I. Kubiaczyk and S. H. Saker, Kamenev-type oscillation criteria for hyeperbolic nonlinear delay difference equations, Demonstratio Math. 36, no. 1 (2003), 113-122.
- S. H. Saker, Oscillation of parabolic neutral delay difference equations with several positive and negative coefficients, Appl. Math. Comp. 143 (1), (2003), 173-186.
- I. Kubiaczyk and S. H. Saker, Oscillation
theorems for discrete nonlinear delay wave equations, Z. Angew.
Math. Mech.
- S. H. Saker, Kamenev-type oscillation criteria for hyperbolic nonlinear neutral delay difference equations, Nonlinear Studies 10 (2003), 221-236.

**Qualitative Analysis of Some
Mathl. Models**

- E. M. Elabbasy and S. H. Saker, Periodic solutions and oscillation of discrete nonlinear delay population dynamics model with external force, IMA J. Appl. Math. (2005), 1-15.
- S. H. Saker and S. Agarwal, Oscillation and global attractivity of a periodic survival red blood cells model, Journal Dynamics of Continuous, Discrete and Impulsive Systems Series B: Applications & Algorithms, (to appear).
- E. M. Elabbasy, S. H. Saker, Dynamics of a class of non-autonomous systems of two non-interacting preys with common predator, J. Appl. Math. Computing, (accepted).
- S. H. Saker and Y. G. Sun, Existence of positive periodic solutions of nonlinear discrete model exhibiting the Allee effect, Appl. Math. Comp. (Accepted).
- S. H. Saker and Y. G. Sun, Oscillatory and asymptotic behavior of positive periodic solutions of nonlinear discrete model exhibiting the Allee effect, Appl. Math. Comp. (Accepted).
- [S. H. Saker, Oscillation and global attractivity of impulsive periodic delay respiratory dynamics model, Chinese Annals Math. (accepted).
- S. H. Saker, Existence of positive periodic solutions of discrete model for the interaction of demand and supply, Nonlinear Functional Analysis and Applications (NFAA), (accepted).
- S. H. Saker, Oscillation of continuous and discrete diffusive delay Nicholson's blowflies models, Appl. Math. Comp. (in press).
- S. H. Saker, Oscillation and global attractivity in hematopoiesis model with periodic coefficients, Appl. Math. Comp. 142 (2-3) (2003), 477-494.
- B. G. Zhang and S. H. Saker, Oscillation
in a discrete partial delay survival red blood cells model, Mathl.
Comp. Modelling
**37**(2003), 659-664. - I. Kubiaczyk and S. H. Saker, Oscillation and global attractivity of discrete survival red blood cells model, Applicationes Mathematicae 30 (2003), 441-449.
- S. H. Saker, Oscillation and global attractivity in a periodic delay hematopoiesis model, J. Appl. Math. Computing 13, (2003), 287-300.
- S. H. Saker, Oscillation and global attractivity of Hematopoiesis model with delay time, Applied Math. Comp. 136 (2003), no.2-3, 27-36.
- S. H. Saker and B. G. Zhang, Oscillation in a discrete partial Nichlson's Blowflies model, Mathl. Comp. Modelling 36 (2002), 9-10, 1021-1026.
- I. Kubiaczyk and S. H. Saker, Oscillation and stability of nonlinear delay differential equations of population dynamics, Mathematical and Computer Modelling 35 (2002), 295-301.
- S. H. Saker and S. Agarwal, Oscillation and global attractivity in a nonlinear delay periodic model of Respiratory Dynamics, Comp. Math. Appl. 44 (2002), 5-6, 623-632.
- S. H. Saker and S. Agarwal, Oscillation and global attractivity in nonlinear delay periodic model of population dynamics, Applicable Analysis 81 (2002), 787 799.
- S. H. Saker and S. Agarwal, Oscillation and global attractivity in a periodic Nicholson's Blowflies model, Mathl. Comp. Modelling 35 (2002), 719-731.
- E. M. Elabbasy, S. H. Saker and K. Saif, Oscillation in Host Macroparasite model with delay time, Far East Journal of Applied Mathematics, Vol. 4, no. 2, (2000), 119-142.

**Dynamic Equations on Time Scales**

- S. H. Saker, Oscillation criteria of second-order half-linear dynamic equations on time scales, J. Comp. Appl. Math. 177(2005), 375-387.
- R. Agarwal, M. Bohner and S. H. Saker, Oscillation criteria for second order delay dynamic equation, Canadian Applied Mathematics Quarterly, (accepted).
- S. H. Saker, Boundedness of solutions of second-order forced nonlinear dynamic equations, Rocky Mountain. J. Math. (accepted).
- *R. P. Agarwal, D. O'Regan and S. H. Saker, Oscillation criteria for second-order nonlinear neutral delay dynamic equations, Journal of Mathematical Analysis and Applications 300 (2004), 203-217.
- S. H. Saker, Oscillation of nonlinear dynamic equations on time scales, Appl. Math. Comp. 148 (2004), 81-91.
- M. Bohner and S. H. Saker, Oscillation of second order nonlinear dynamic equations on time scales, Rocky Mountain J. Math. 34, no. 4 (2004), 1239-1254.
- M. Bohner and S. H. Saker, Oscillation criteria for perturbed nonlinear dynamic equations, Mathl. Comp. Modeling 40 (2004), 3-4, 249 260.
- L. Erbe, A. Peterson and S. H. Saker, Oscillation criteria for second-order nonlinear dynamic equations on time scales. J. London Math. Soc. 76 (2003), 701-714.
- E. A. Bohner, M. Bohner and S. H. Saker, Oscillation for a certain of class of second order Emden-Fowler dynamic equations, Electr. Transaction Numerical Anal. (to appear).

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