Preferred Language
Articles
/
URfCNY8BVTCNdQwCKWI1
A combined compact genetic algorithm and local search method for optimizing the ARMA(1,1) model of a likelihood estimator
...Show More Authors

In this paper, a compact genetic algorithm (CGA) is enhanced by integrating its selection strategy with a steepest descent algorithm (SDA) as a local search method to give I-CGA-SDA. This system is an attempt to avoid the large CPU time and computational complexity of the standard genetic algorithm. Here, CGA dramatically reduces the number of bits required to store the population and has a faster convergence. Consequently, this integrated system is used to optimize the maximum likelihood function lnL(φ1, θ1) of the mixed model. Simulation results based on MSE were compared with those obtained from the SDA and showed that the hybrid genetic algorithm (HGA) and I-CGA-SDA can give a good estimator of (φ1, θ1) for the ARMA(1,1) model. Another comparison has been conducted to show that the I-CGA-SDA has fewer function evaluations, minimum search space percentage, faster convergence speed and has a higher optimal precision than that of the HGA.

Scopus Clarivate Crossref
View Publication
Publication Date
Sat Jan 04 2014
Journal Name
Journal Of Materials And Chemical Engineering
The Effect of Atomic Percentage Selenium Content on the Permittivity and Polarizability of Ge1-xSex thin films
...Show More Authors

Generally the a.c. conductivity shows a power law in frequency s  ()  where the exponent s ≤ 1. As the frequency goes to zero the conductivity become frequency independent. The a.c. conductivity was studied for the Ge1-xSex thin films to see how the selenium contents affect the permittivity and the permeability for the Ge1-x Sex. The thin films prepared by thermal evaporation at room temperature and under vacuum (~2 x10-5toor) using Edward coating unit model 306A. From the relation between ln conductivity and ln w, the effect of selenium contents in Ge1-x Sex thin films on the exponent value, the relaxation time and the maximum barrier height. An algebric fitting method for circles and circular arcs was used to find the permit

... Show More
Preview PDF
Publication Date
Sun Feb 26 2012
Journal Name
Ibn Al-haitham Journal For Pure And Applied Science
Study the Effect of Annealing Temperature on the Structural, Optical and Electrical Properties of ZnS Thin Films
...Show More Authors

The structural, optical and electrical properties of ZnS films prepared by vacuum evaporation technique on glass substrate at room temperature and treated at different annealing temperatures (323, 373, 423)K of thickness (0.5)µm have been studied. The structure of these films is determined by X-ray diffraction (XRD). The X-ray diffraction studies show that the structure is polycrystalline with cubic structure, and there are strong peaks at the direction (111). The optical properties investigated which include the absorbance and transmittance spectra, energy band gab, absorption coefficient, and other optical constants. The results showed that films have direct optical transition. The optical band gab was found to be in the range t

... Show More
Publication Date
Sat Jun 15 2019
Journal Name
Journal Of The College Of Basic Education
The Effect Of Phoenix Dactylifera L. Pinnae Reinforcement On The Mechanical And Thermal Properties Of Polymer Composite
...Show More Authors

Phoenix dactylifera l. pinnae (the green leaves of dates palm) were used as natural reinforcing (strengthening) fibers to improve the mechanical properties of polyester as a matrix material, the fibers of the green leaves of dates palm were used in two lengths, 10 and 20mm with five rates of 0, 2.5, 5, 10, and 20% , where the reinforcing with the leaves fibers increases the hardness strength from 76.5 to be about 86.55 , the Impact value raised from about 0.313 to 0.461 , in addition to that the flexural strength from 2.66 to be about 55 , and the thermal conductivity increases from 2.54 𝑤∕𝑚.℃ to 5.41 𝑤∕𝑚.℃. The results of the present search explains that the composite samples reinforced at rate 20% and 10mm fiber length

... Show More
Publication Date
Sun Oct 07 2012
Journal Name
Journal Of Educational And Psychological Researches
Problems that facing the philosophy of education in the variables of knowledge and Informatics society (techno _ social).
...Show More Authors

This research includes problems that facing the philosophy of education in the variables of knowledge and Informatics society (techno _ social).

 The problematic research included three questions:

 1- What are the concepts and characterization related to the problematic of relationship between the philosophy of education and informatics variables (techno - social).

2-What kind of problems facing speech philosophy of education in the variables information (techno - social)

  3 - What are the perceptions of educational proposed to address problematic philosophy of education in the scope of human (human nature) and (values ​​and morals), in addition the research may explain the co

... Show More
View Publication Preview PDF
Publication Date
Thu Feb 28 2019
Journal Name
Iraqi Journal Of Science
Facies Analysis and Sequence Stratigraphy of the Zubair Formation in the Kifl oil field, Central of Iraq
...Show More Authors

The Zubair Formation is the most significant sandstone reservoir in Iraq which deposited during the Barremian. The study area is located in the central part of Iraq at the Kifl oil field, in the northern part of the Mesopotamian Zone.

The petrographic study showed that quartz mineral is the main component of the sandstone in Zubair Formation with very low percentage of feldspar and rare rock fragments to classified as quartz arenite sandtone. There are five lithologic changes (lithofacies) that have characterized the studied succession: - well sorted quartz arenite, poorly sorted quartz arenite, poorly sorted graywacke, sandy shale, and shale.  These lithofacieses were deposited in the deltaic environments as three associate

... Show More
View Publication Preview PDF
Publication Date
Mon Jan 01 2024
Journal Name
Scripta Medica
The value of dynamic contrast-enhanced MRI and diffusion-weighted sequence in the evaluation of endometrial lesions
...Show More Authors

Background/Aim: Endometrial abnormalities represent a diagnostic challenge due to overlapping imaging features with normal endometrium. Aim of this study was to assess accuracy of dynamic contrast-enhanced and diffusion-weighted magnetic resonance imaging (MRI) in evaluation of endometrial lesions in comparison with T2 and to assess local staging validity and degree of myometrial invasion in malignancy. Methods: Forty patients with abnormal vaginal bleeding or sonographic thickened endometrial were recruited. MRI examination of pelvis was per-formed using 1.5 T scanner with a pelvic array coil. Conventional T1-and T2, dynamic contrast-enhanced (DCE) sequences and diffusion-weighted image (DWI) were performed. Results: Mean age of pa

... Show More
View Publication
Crossref (1)
Scopus Crossref
Publication Date
Sun Jan 01 2012
Journal Name
Al-taqni Journal
The Frequency of Urinary Tract Infection According to the Age and Sex in Some of Iraqi Children.
...Show More Authors

Publication Date
Sun Jan 13 2019
Journal Name
Iraqi Journal Of Physics
The effect of short range correlation on the inelastic C2 and C4 form factors of 18O nucleus
...Show More Authors

The effect of short range correlations on the inelastic Coulomb form factors for excited +2 states (1.982, 3.919, 5.250 and 8.210MeV) and +4 states (3.553, 7.114, 8.960 and 10.310 MeV) in O18 is analyzed. This effect (which depends on the correlation parameterβ) is inserted into the ground state charge density distribution through the Jastrow type correlation function. The single particle harmonic oscillator wave function is used with an oscillator size parameter .b The parameters β and b are adjusted for each excited state separately so as to reproduce the experimental root mean square charge radius of .18O The nucleusO18 is considered as an inert core of C12 with two protons and four neutrons distributed over 212521211sdp−− activ

... Show More
View Publication Preview PDF
Crossref
Publication Date
Fri Jun 30 2023
Journal Name
Iraqi Journal Of Science
The Relation Between the Variation of Electrical Resistivity Values and Moisture of Soil at Baghdad University, Iraq
...Show More Authors

     Six ERI profiles using Wenner Schlumberger array were carried out at Baghdad University (ALJadiriya campus) to investigate soil at two sites. The spacing between electrodes of four profiles surrounding the new building in the Campus at the first site is 1 m, and the profile length ranges from 50 to 90 m. In comparison, two across profiles in the garden to detect water seepage in the site. The inverted model of the studied profiles shows many high and low resistivity zone. The sedimentology and mineralogy of the soil samples analysis from a depth range of 15 to 100 cm from three pits confirm the high homogeneity of the soil in the studied site composed of (silt and clay). The low resistivity values coincided with the moisture a

... Show More
View Publication Preview PDF
Scopus (1)
Scopus Crossref
Publication Date
Tue Oct 18 2022
Journal Name
Applied Sciences
The Influence of Flight Direction and Camera Orientation on the Quality Products of UAV-Based SfM-Photogrammetry
...Show More Authors

Unmanned aerial vehicles (UAVs) can provide valuable spatial information products for many projects across a wide range of applications. One of the major challenges in this discipline is the quality of positioning accuracy of the resulting mapping products in professional photogrammetric projects. This is especially true when using low-cost UAV systems equipped with GNSS receivers for navigation. In this study, the influence of UAV flight direction and camera orientation on positioning accuracy in an urban area on the west bank of the Euphrates river in Iraq was investigated. Positioning accuracy was tested in this study with different flight directions and camera orientation settings using a UAV autopilot app (Pix4Dcapture software

... Show More
View Publication
Scopus (10)
Crossref (6)
Scopus Clarivate Crossref