Sttudy tthe oriienttattiion and diisttance ffacttors effffectts on tthe llower usablle ffrequency ((LUF)) over miiddlle eastt regiion

Khalid A. Hadi

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Publication Date

Mon Oct 01 2012

Journal Name

Iraqi Journal Of Physics

Volume

10

Issue Number

18

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Sttudy tthe oriienttattiion and diisttance ffacttors effffectts on tthe llower usablle ffrequency ((LUF)) over miiddlle eastt regiion

Radio Wave Propagation

LUF

Lowest Usable Frequency

HF-Models

Khalid A. Hadi

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In this research, the influence of the orientation and distance factors on the lowest usable frequency (LUF) parameter has been studied theoretically. The calculations of the (LUF) parameter have been made using the (VOACAP) international communication model for the connection links between the capital Baghdad and many other locations that distributed on different distances and directions over the Middle East region. The results shown in this study indicate there is a slight affection of the link direction (orientation) on the LUF parameter, while the influence of the distance factor is more significant on the values of the LUF parameter. The day/night effect appears for the long distance HF links (i.e. more than a 500 Km)

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Publication Date

Sun Jul 20 2025

Journal Name

Ibn Al-haitham Journal For Pure And Applied Sciences

Using a 3D Chaotic Dynamic System as a Random Key Generator for Image Steganography

Random Key Generator

Chaotic Dynamic System

Information Security

Spatial Domain

Frequency Domain

Chaos

Lyapunov Exponents

Fractal Dimension

Bifurcation

Mohammed Abod

Saad

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In today's digital era, the importance of securing information has reached critical levels. Steganography is one of the methods used for this purpose by hiding sensitive data within other files. This study introduces an approach utilizing a chaotic dynamic system as a random key generator, governing both the selection of hiding locations within an image and the amount of data concealed in each location. The security of the steganography approach is considerably improved by using this random procedure. A 3D dynamic system with nine parameters influencing its behavior was carefully chosen. For each parameter, suitable interval values were determined to guarantee the system's chaotic behavior. Analysis of chaotic performance is given using the

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Publication Date

Mon Feb 04 2019

Journal Name

Iraqi Journal Of Physics

Evaluated the level density for proton induced nuclear resonances in (P+48Ti) reaction using different models

Level density

proton resonance

GOE version RMT model

CT and BSFG models

NNSD

modified porter Thomas distribution.

Mahdi Hadi

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The experimental proton resonance data for the reaction P+48Ti have been used to calculate and evaluate the level density by employed the Gaussian Orthogonal Ensemble, GOE version of RMT, Constant Temperature, CT and Back Shifted Fermi Gas, BSFG models at certain spin-parity and at different proton energies. The results of GOE model are found in agreement with other, while the level density calculated using the BSFG Model showed less values with spin dependence more than parity, due the limitation in the parameters (level density parameter, a, Energy shift parameter, E1and spin cut off parameter, σc). Also, in the CT Model the level density results depend mainly on two parameters (T and ground state back shift energy, E0), which are app

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Publication Date

Wed Jan 01 2020

Journal Name

Periodicals Of Engineering And Natural Sciences

Comparison between the estimated of nonparametric methods by using the methodology of quantile regression models

Stratified quantile regression

quantile function

marginal model

conditional model

B-spline

kernel regression (Nadaraya-Watson)

varying coefficient models

Qutiaba

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This paper study two stratified quantile regression models of the marginal and the conditional varieties. We estimate the quantile functions of these models by using two nonparametric methods of smoothing spline (B-spline) and kernel regression (Nadaraya-Watson). The estimates can be obtained by solve nonparametric quantile regression problem which means minimizing the quantile regression objective functions and using the approach of varying coefficient models. The main goal is discussing the comparison between the estimators of the two nonparametric methods and adopting the best one between them

Publication Date

Wed May 10 2023

Journal Name

Journal Of Engineering

SDPLL-Based Frequency Estimation of a Sinusoid in Colored Noise

Sinusoidal digital phase-locked loop (SDPLL)

Cramer-Rao bound (CRB)

colored noise

frequency error variance

signal-to-noise ratio (SNR).

Nuha Abdul Sahib

Zainab Hassan

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The problem of frequency estimation of a single sinusoid observed in colored noise is addressed. Our estimator is based on the operation of the sinusoidal digital phase-locked loop (SDPLL) which carries the frequency information in its phase error after the noisy sinusoid has been acquired by the SDPLL. We show by computer simulations that this frequency estimator beats the Cramer-Rao bound (CRB) on the frequency error variance for moderate and high SNRs when the colored noise has a general low-pass filtered (LPF) characteristic, thereby outperforming, in terms of frequency error variance, several existing techniques some of which are, in addition, computationally demanding. Moreover, the present approach generalizes on existing work tha

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Publication Date

Mon Jan 13 2020

Journal Name

Day 3 Wed, January 15, 2020

Numerical Simulation of Gas Lift Optimization Using Genetic Algorithm for a Middle East Oil Field: Feasibility Study

Constrained optimization

Gas lifts

Gases

Gasoline

Genetic algorithms

Life cycle

Natural gas fields

Numerical models

Offshore oil well production

Oil fields

Mustafa

Mofazzal

Omar

Akim

Abbas

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<p>Gas-lift technique plays an important role in sustaining oil production, especially from a mature field when the reservoirs’ natural energy becomes insufficient. However, optimally allocation of the gas injection rate in a large field through its gas-lift network system towards maximization of oil production rate is a challenging task. The conventional gas-lift optimization problems may become inefficient and incapable of modelling the gas-lift optimization in a large network system with problems associated with multi-objective, multi-constrained, and limited gas injection rate. The key objective of this study is to assess the feasibility of utilizing the Genetic Algorithm (GA) technique to optimize t</p> ... Show More

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Publication Date

Thu Jun 30 2011

Journal Name

Al-khwarizmi Engineering Journal

Nahrain Mobile Learning System (NMLS)

Nahrain mobile learning system

short message service

wireless application protocols

multimedia messaging service

mobile learning

personal digital assistant

wireless fidelity

general packet radio service

extensible hypertext markup language

java database connectivity

Mahmood Sami

Mumtaz

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The work in this paper involves the planning, design and implementation of a mobile learning system called Nahrain Mobile Learning System (NMLS). This system provides complete teaching resources, which can be accessed by the students, instructors and administrators through the mobile phones. It presents a viable alternative to Electronic learning. It focuses on the mobility and flexibility of the learning practice, and emphasizes the interaction between the learner and learning content. System users are categorized into three categories: administrators, instructors and students. Different learning activities can be carried out throughout the system, offering necessary communication tools to allow the users to communicate with each other

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Publication Date

Mon Apr 01 2013

Journal Name

International Journal Of Electrical, Electronics And Telecommunication Engineering

Performance Analysis of xPON Network for Different Queuing Models

—Passive optical network (PON)

Interleaved Polling with Adaptive Cycle Time (IPACT)

Dynamic Bandwidth Allocation (DBA)

Queuing models

Optical line terminal (OLT)

Optical node user (ONU)

Nahlah Abdulrahman

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Passive optical network (PON) is a point to multipoint, bidirectional, high rate optical network for data communication. Different standards of PONs are being implemented, first of all PON was ATM PON (APON) which evolved in Broadband PON (BPON). The two major types are Ethernet PON (EPON) and Gigabit passive optical network (GPON). PON with these different standards is called xPON. To have an efficient performance for the last two standards of PON, some important issues will considered. In our work we will integrate a network with different queuing models such M/M/1 and M/M/m model. After analyzing IPACT as a DBA scheme for this integrated network, we modulate cycle time, traffic load, throughput, utilization and overall delay

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Publication Date

Wed Jan 02 2019

Journal Name

Journal Of The College Of Languages (jcl)

A traditional model of translation: Critical analysis: Традиционные модели перевода: критический анализ

traditional translation models

theory of formal and dynamic equivalence

theory of regular correspondences

informative

situational-denotative

functional-pragmatic theory of communication levels.

традиционные модели перевода

теория формальной и динамической эквивалентности

теория закономерных соответствий

информативная

ситуативно-денотативная

функционально-прагматическая теория уровней коммуникации

Ali Kadhim

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The article critically analyzes traditional translation models. The most influential models of translation in the second half of the 20th century have been mentioned, among which the theory of formal and dynamic equivalence, the theory of regular correspondences, informative, situational-denotative, functional-pragmatic theory of communication levels have been considered. The selected models have been analyzed from the point of view of the universality of their use for different types and types of translation, as well as the ability to comprehend the deep links established between the original and the translation.

Аннотация

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Publication Date

Fri Mar 01 2019

Journal Name

Applied Acoustics

Theoretical model of absorption coefficient of an inhomogeneous MPP absorber with multi-cavity depths

Micro-perforated panel (MPP) absorber has been known as an alternative absorber to classical porous material given its facile installation

long durability

environmental friendliness and attractive appearance. Extensive studies of MPP absorber proposing the improvement of its absorption frequency bandwidth have been published. This study presents a MPP absorber introduced with inhomogeneous perforations and with multi-cavity depths. The MPP is divided into two sub-area

where each area has different hole diameter

perforation ratio and a separated backed cavity depth. The acoustic impedance is modelled using electrical equivalent circuit and the absorption coefficient is calculated under normal-incidence of sound. It is found that the inhomogeneous MPP can have good bandwidth of absorption by designing the sub-MPP of smaller perforation ratio with large hole diameter and the one having the larger perforation ratio with smaller hole diameter. The absorption bandwidth can be conveniently controlled by adjusting the cavity depth of each sub-MPP. The results from the experimental work show good agreement with the theoretical model.

Ali Ibrahim

Azma

Roszaidi

Iwan

Al-Ameri

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(67)

Publication Date

Sat Oct 01 2016

Journal Name

Journal Of Theoretical And Applied Information Technology

Factors affecting global virtual teams’ performance in software projects

Today the trend is to perform software development work via distributed geographical area among team

individual or even as an organization. However

due to the global market and international presence of many companies

there is a need to implement a global virtual teams. The global virtual team members are gradually engaged in globalized business environments across space

time and organizational boundaries via information and communication technologies. A global virtual team relies on communication

collaboration

and information exchange are the most important criteria in global virtual teams’ operations. The purpose of this paper is to answer two research questions. The first research question is to identify the factors affecting global virtual teams’ performance. A systematic literature review was conducted to answer the first research question. The second research question is on what the rank of the factor affecting the global virtual teams’ performance according to their level of effect on global virtual teams’ performance. Online survey was conducted within 103 developers and IT managers from eight IT companies to answer the second research question. The Statistical Package for Social Science (SPSS 22) was used to analyze the collected data. In this study

we investigated factors that affect global virtual teams’ performance

factors considered include cultural differences

language problems

time-zone differences

team size

technical problems

lack of trust

lack of sufficient training

and ICT problems. Also the findings indicated that lack of sufficient training is the highest level of effect on global virtual teams’ performance. On the other hand

Ali Yahya Gheni

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