Ivan Subhi Latif

Ivan Subhi Latif
Salahaddin University - Erbil | SUH · College of Education

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18
Publications
295
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196
Citations

Publications

Publications (18)
Article
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In this paper, we study the global convergence properties of the new class of preconditioned conjugate gradient descent algorithm, when applied to convex objective non-linear unconstrained optimization functions. We assume that a new inexact line search rule which is similar to the Armijo line-search rule is used. It's an estimation formula to choo...
Article
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In this paper, a new combined extended Conjugate-Gradient (CG) and Variable-Metric (VM) methods is proposed for solving unconstrained large-scale numerical optimization problems. The basic idea is to choose a combination of the current gradient and some pervious search directions as a new search direction updated by Al-Bayati's SCVM-method to fit a...
Article
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In this paper, we have proposed a modified QN-algorithm for solving a self-scaling large scale unconstrained optimization problems based on a new QN-update. The performance of the proposed algorithm is better than that used by Wei, Li, Yuan algorithm. Our numerical tests show that the new proposed algorithm seems to converge faster as compared with...
Article
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In this work we present a new algorithm of gradient descent type, in which the stepsize is computed by means of simple approximation of the Hessian Matrix to solve nonlinear unconstrained optimization function. The new proposed algorithm considers a new approximation of the Hessian based on the function values and its gradients in two successive po...
Article
In this work we present the gradient descent Algorithm for solving unconstrained optimization problem, there are many ways to choose the step size. In this paper we propose a new non-monotone line search which has many advantages comparing with other similar inexact line searches. Numerical experiments on Fifteenth well-Know test functions with var...
Article
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In this paper, we have presented a numerical algorithm for the step-size estimation for minimization problems. Global convergence results are derived for descent algorithms in which the line search step is replaced by a step whose length is determined by step-size estimation formula. Numerical results show that the new estimation step-size required...
Article
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In the present study, we proposed a three-term of preconditioned gradient memory algorithms to solve a nonlinear optimization problem. The new algorithm subsumes some other families of nonlinear preconditioned gradient memory algorithms as its subfamilies with Powell's Restart Criterion and inexact Armijo line searches. Numerical experiments on twe...
Article
In this paper, a new PCG descent algorithm is proposed using an exact line search to solve a nonlinear unconstrained optimization problem.The algorithm redused to a version of the (Anderi N., 2006) conjugate descent algorithm and uses (Oren S. S., 1974) self scaling VM-algorithm to solve a large-scale unconstrained optimization problems. The global...
Article
In this paper, we shall try to determine outliers and pinpoint its source of existence by using box- whisker- plots technique which is an effective approach to detect and treat outliers. Thus the researchers prove that the Box-Whisker-Plot is a most effective method among other methods used in this research which is the hypothesis paper.
Article
Full-text available
We present here the results of our x-ray, high pressure and dielectric studies on a reentrant nematogenic mixture of n-dodecyl-4-(4-ethoxybenzylideneamino)-α-methylcinnamate and 4-n-heptyloxyphenyl-4-(4-ethylcyclohexanoyloxy)benzoate, neither of which possesses a strongly polar end group. The layer spacing measurements show that the smectic A phase...
Article
We report the observation of a partially bilayer smectic A phase in n-dodecyl-4-(4-ethoxybenzylidene amino)-α-methylcinnamate, a compound which does not possess a strongly polar cyano or nitro end group. The ratio of the layer spacing to molecular length is found to be about 1.12. The dielectric anisotropy versus temperature plot exhibits a reversa...
Article
The phase diagrams of nine binary systems containing recentrant nematic phases in the sequence Nre SA N and Sc Nre SA N are presented. In these mixtures both components are of the trminal-nonpolar type. X-ray diffraction studies of three systems were carried out. The relationship between the form of the phase diagrams and the chemical nature and po...
Article
In 15 Substances of general formula transition temperatures, transition enthalpies and entropies, densities and phase transition volumina, order parameters of a dissolved dye and optical refractive indices were measured. Additional miscibility and X-ray investigations were performed. The results are discussed on the basis of molecular statistical...
Article
A binary system of terminal-nonpolar compounds is prsented in which the phase sequence N SA SC SA was observed with decreasing temperature. This new phase sequence was detected by microscopic, conoscopic, and X-ray investigations. © 1985 Gordon and Breach, Science Publishers. Inc. and OPA Ltd.
Article
A binary system of terminal-nonpolar compounds is presented in which a stable reentrant nematic phase occurs. X-ray investigations were carried out in the N, SA, Nre, and SC phase.

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