Preferred Language
Articles
/
jeasiq-1344
Comparison of Multistage and Numerical Discretization Methods for Estimating Parameters in Nonlinear Linear Ordinary Differential Equations Models.
...Show More Authors

Many of the dynamic processes in different sciences are described by models of differential equations. These models explain the change in the behavior of the studied process over time by linking the behavior of the process under study with its derivatives. These models often contain constant and time-varying parameters that vary according to the nature of the process under study in this We will estimate the constant and time-varying parameters in a sequential method in several stages. In the first stage, the state variables and their derivatives are estimated in the method of penalized splines(p- splines) . In the second stage we use pseudo lest square to estimate constant parameters, For the third stage, the remaining constant parameters and time-varying parameters are estimated by using a semi-parametric regression model and then comparing this method with methods based on numerical discretization methods, which includes two stages. In the first stage we estimate the state variables and their derivatives by (p spline) , In the second stage we use Methods of numerical discretization methods (the Euler discretization method  and the trapezoidal discretization method), where the comparison was done using simulations and showed the results superior to the trapezoidal method of numerical differentiation where it gave the best estimations to balance between accuracy in estimation And high arithmetic cost.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Thu Dec 01 2011
Journal Name
Iraqi Journal Of Physics
vStudy of Linear Shrinkage for Siliceous Materials to Meet Insulating Requirements
...Show More Authors

Iraqi siliceous rocks were chosen to be used as raw materials in this study which is concern with the linear shrinkage and their related parameters. They are porcelinite from Safra area (western desert) and Kaolin Duekla, their powders were mixed in certain percentage, to shape compacts and sintered. The study followed with thermal and chemical treatments, which are calcination and acid washing. The effects on final compact properties such as linear shrinkage were studied. Linear shrinkage was calculated for sintered compacts to study the effects of calcination processes, chemical washing, weight percentage, sintering processes, loading moment were studied on this property where the compacts for groups is insulating materials.
Linear

... Show More
View Publication Preview PDF
Publication Date
Mon Apr 01 2019
Journal Name
Journal Of Engineering
Design of New Hybrid Neural Controller for Nonlinear CSTR System based on Identification
...Show More Authors

This paper proposes improving the structure of the neural controller based on the identification model for nonlinear systems. The goal of this work is to employ the structure of the Modified Elman Neural Network (MENN) model into the NARMA-L2 structure instead of Multi-Layer Perceptron (MLP) model in order to construct a new hybrid neural structure that can be used as an identifier model and a nonlinear controller for the SISO linear or nonlinear systems. Two learning algorithms are used to adjust the parameters weight of the hybrid neural structure with its serial-parallel configuration; the first one is supervised learning algorithm based Back Propagation Algorithm (BPA) and the second one is an intelligent algorithm n

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Sun Mar 01 2020
Journal Name
Baghdad Science Journal
Dynamic Response of a Nonlinear Fabry-Perot Etalon for Various Medium Response Times
...Show More Authors

     In this work, the switching nonlinear dynamics of a Fabry-Perot etalon are studied. The method used to complete the solution of the differential equations for the nonlinear medium. The Debye relaxation equations solved numerically to predict the behavior of the cavity for modulated input power. The response of the cavity filled with materials of different response time is depicted. For a material with a response time equal to = 50 ns, the cavity switches after about (100 ns). Notice that there is always a finite time delay before the cavity switches. The switch up time is much longer than the cavity build-up time of the corresponding linear cavity which was found to be of the order of a few round-trip ti

... Show More
View Publication Preview PDF
Scopus (2)
Crossref (1)
Scopus Clarivate Crossref
Publication Date
Thu Feb 28 2019
Journal Name
Journal Of Engineering
Frequency Domain Analysis for Geometric Nonlinear Seismic Response of Tall Reinforced Concrete Buildings
...Show More Authors

This paper aims to study the second-order geometric nonlinearity effects of P-Delta on the dynamic response of tall reinforced concrete buildings due to a wide range of earthquake ground motion forces, including minor earthquake up to moderate and strong earthquakes. The frequency domain dynamic analysis procedure was used for response assessment. Reinforced concrete building models with different heights up to 50 stories were analyzed. The finite element software ETABS (version 16.0.3) was used to analyze reinforced concrete building models.

The study reveals that the percentage increase in buildings' sway and drift due to P-Delta effects are nearly constant for specific building height irrespective of the seism

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Thu Oct 01 2020
Journal Name
Alexandria Engineering Journal
The operational matrix of Legendre polynomials for solving nonlinear thin film flow problems
...Show More Authors

View Publication
Crossref (12)
Crossref
Publication Date
Thu Oct 01 2020
Journal Name
Alexandria Engineering Journal
The operational matrix of Legendre polynomials for solving nonlinear thin film flow problems
...Show More Authors

Scopus (17)
Crossref (12)
Scopus Clarivate Crossref
Publication Date
Tue Mar 01 2016
Journal Name
Optics Communications
Temperature effect on nonlinear refractive indices of liquid crystals in visible and NIR
...Show More Authors

View Publication
Scopus (12)
Crossref (12)
Scopus Clarivate Crossref
Publication Date
Thu Jan 01 2015
Journal Name
Aip Conference Proceedings
Numerical solution for weight reduction model due to health campaigns in Spain
...Show More Authors

This paper introduces a non-conventional approach with multi-dimensional random sampling to solve a cocaine abuse model with statistical probability. The mean Latin hypercube finite difference (MLHFD) method is proposed for the first time via hybrid integration of the classical numerical finite difference (FD) formula with Latin hypercube sampling (LHS) technique to create a random distribution for the model parameters which are dependent on time t . The LHS technique gives advantage to MLHFD method to produce fast variation of the parameters’ values via number of multidimensional simulations (100, 1000 and 5000). The generated Latin hypercube sample which is random or non-deterministic in nature is further integrated with the FD method t

... Show More
View Publication
Scopus (4)
Crossref (1)
Scopus Clarivate Crossref
Publication Date
Tue Sep 01 2020
Journal Name
Baghdad Science Journal
On The Normality Set of Linear Operators
...Show More Authors

            In this paper, the Normality set  will be investigated. Then, the study highlights some concepts properties and important results. In addition, it will prove that every operator with normality set has non trivial invariant subspace of  .

 

View Publication Preview PDF
Scopus (3)
Crossref (2)
Scopus Clarivate Crossref
Publication Date
Sun Jun 05 2016
Journal Name
Baghdad Science Journal
Flame Atomic Emission and Colorimetric Methods for the Determination of Cephalexin Monohydrate in Pharmaceutical Preparations
...Show More Authors

We propose two simple, rapid, and convenient spectrophotometric methods which are described for the determination of cephalexin in bulk and its pharmaceutical preparations. They are based on the measurement of the flame atomic emission of potassium ion (in the first method) and colorimetric determination of the green colored solution at 610 nm formed after the reaction of cephalexin with potassium permanganate as an oxidant agent (in the second method) in basic medium. The working conditions of the methods are investigated and optimized. Beer's law plot shows a good correlation in the concentration range of 5-40?g ml-1. The detection limits are 2.573,2.814 ?g ml-1 for the flame emission photometric method and 1.844,2.016 ?g ml-1 for colo

... Show More
View Publication Preview PDF
Crossref