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A Comparative Study for Estimate Fractional Parameter of ARFIMA Model

      Long memory analysis is one of the most active areas in econometrics and time series where various methods have been introduced to identify and estimate the long memory parameter in partially integrated time series. One of the most common models used to represent time series that have a long memory is the ARFIMA (Auto Regressive Fractional Integration Moving Average Model) which diffs are a fractional number called the fractional parameter. To analyze and determine the ARFIMA model, the fractal parameter must be estimated. There are many methods for fractional parameter estimation. In this research, the estimation methods were divided into indirect methods, where the Hurst parameter is estimated first, and then the fractional integration parameter is estimated from it by a relation between them. As for direct methods, the fractional integration parameter is estimated directly without relying on Hurst's parameter, and most of them are semi parametric methods. In this paper, some of the most common direct methods were used to estimate the fraction modulus namely (Geweke-Porter-Hudak, Smoothed Geweke-Porter-Hudak, Local Whittle, Wavelet and weighted wavelet), using simulation method with different value of (d) and different size of time series. The comparison between the methods was done using the mean squared error (MSE). It turns out that the best methods to estimate the fractional parameter is (Local Whittle).

      The ARFIMA model was generated by a function programmed by the MATLAB statistical program

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Publication Date
Wed Dec 15 2021
Journal Name
Abstract And Applied Analysis
Dynamical Behaviors of a Fractional-Order Three Dimensional Prey-Predator Model

In this paper, the dynamical behavior of a three-dimensional fractional-order prey-predator model is investigated with Holling type III functional response and constant rate harvesting. It is assumed that the middle predator species consumes only the prey species, and the top predator species consumes only the middle predator species. We also prove the boundedness, the non-negativity, the uniqueness, and the existence of the solutions of the proposed model. Then, all possible equilibria are determined, and the dynamical behaviors of the proposed model around the equilibrium points are investigated. Finally, numerical simulations results are presented to confirm the theoretical results and to give a better understanding of the dynami

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Publication Date
Fri Mar 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
Comparison for estimation methods for the autoregressive approximations

Abstract

      In this study, we compare between the autoregressive approximations (Yule-Walker equations, Least Squares , Least Squares ( forward- backword ) and Burg’s (Geometric and Harmonic ) methods, to determine the optimal approximation to the time series generated from the first - order moving Average non-invertible process, and fractionally - integrated noise process, with several values for d (d=0.15,0.25,0.35,0.45) for different sample sizes (small,median,large)for two processes . We depend on figure of merit function which proposed by author Shibata in 1980, to determine the theoretical optimal order according to min

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Publication Date
Tue Dec 22 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Accounting Disclosure for non-current intangible assets according to international accounting standard (IAS16, 36): A Comparative Study of the State Company for Travelers and delegates Transportations

The Accounting Disclosure for non-current intangible assets is necessary to rely on accounting information by decision makers in the economic unity, two international accounting standards issued (IAS16,36), which aims to provide the foundations of the recognition, measurement and disclosure of appropriate assets Non-current tangible. (IAS16) allowed to use re-evaluation approach to measure assets entrance due to the inadequacy of the accounting information resulting from the application of the historical cost of the entrance under increasing technical developments and continuing that leave clear their effects on non-current intangible assets, As well as the requirements of what came (IAS36) the importance of accounting for the impairment

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Publication Date
Mon Jan 01 2018
Journal Name
Ibn Al-haitham J. For Pure & Appl. Sci
Comparative Anatomical Study between Typhadomengensis and Phragmites communis

Both of the species Typha domengensis and Phragmites communis among the most important plant endemic in flora of Iraq from monocotyledon. Due to the similarity of the two species with each other in many morphological characteristics such as the environment where they live and the form of leaves and type of leaf venation and type of stomata….ets, also both of species belong to monocots plant therefore this research work was conducted find anatomical differences that have the same as taxonomic value to help distinguishing between both species under study. Through this research, we found great importance to the anatomical characteristics which we reached by studying the roots, stems and leaves sections f

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Publication Date
Thu Jun 15 2023
Journal Name
Journal Of Legal Sciences
Human Right to Citizenship in International Conventions and Omani Legislation: Comparative Study

The idea of citizenship is one of the old political and legal ideas that have long occupied a wide area of thinking in most countries of the world because the right of citizenship is linked to the identity and cultural reference of human persons of different origins and ethnicities. Citizenship is the equality of citizens irrespective of religious, sectarian, tribal, ethnic, or sexual tinctures. Countries sought to enshrine this right through international conventions, affirmed through the constitutions, statutes, laws, and media of States, to increase the association of individuals affiliated with the State with their national identity and to grant these individuals all their rights under international conventions, constitutions, or dom

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Publication Date
Wed Jul 28 2021
Journal Name
Journal Of Legal Sciences
The Quasi-Contract in the English Law. A Comparative Study with the Unjustly Paid in the Iraqi Civil Law

Quasi-contract is considered as one of the well-established legal systems of the English Common law of customary origins, which is unwritten and based upon judicial precedents of the English courts. It is worth-bearing in mind that the legal basis of quasi-contract passed into two different stages: in the first stage the English judicature, supported by some juristic opinions regarded it as an implied Contract made by courts to prevent one party from being unjustly enriched at the expense of the other. Whereas in the second stage the English judicature considered it as an independent source of obligation، based upon the law of restitution. and having nothing to do with the law of contract. The Iraqi civil law No. (40) of 1951 regulated

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Publication Date
Mon Dec 31 2018
Journal Name
Journal Of The Faculty Of Medicine Baghdad
Dyslipidemia and CA15-3 serum level in Iraqi Women with Breast Tumor: A Comparative Study

Background: Lipids seem to have a direct influence in women breast cancer (BC) or dyslipidemia may be a consequence of this cancer.

Objective: the aim of this study is to define serum levels of lipid profile in women with breast cancer (BC) and to compare that with fibroadenoma benign breast tumor. Also, to assess the role of serum CA 15-3 in early diagnosis of breast cancer (BC).   
Patients and Methods:
This case study was carried out at Biochemistry Department, College of Medicine, University of Baghdad, during the period from February 2017 to November 2017. It included 38 Iraqi women diagnosed with primary breast cancer (BC, Group-I) and 25 women with Fibroadenom

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Publication Date
Fri Dec 01 2017
Journal Name
Journal Of Legal Sciences
The Legal System Of Arbitration As a Name Of Setting Foreign Investment Disputes in Iraqi and Kurdistan Region legislation: A COMPARATIVE LEGAL STUDY

Is a theme of foreign direct investment and indirect interest of the world, especially developing countries, and the growing interest in recent issue of investment in Iraq and the region being one of the countries aspiring to attract foreign investment, especially in the natural resources sector, having changed relatively Look uncertainty towards foreign investors, both of by the state or its citizens.

Although mutual cooperation between the state invested and investors to identify those rights and obligations in terms of scope or content of the contract between the parties, but it might get a conflict between the two parties in the exact content of the rights enjoyed by the investor and the obligations due to breach of one of th

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Publication Date
Sat Oct 20 2018
Journal Name
Journal Of Economics And Administrative Sciences
Evaluation of the Quality of Health Services from Patients’ Perspective: A Comparative Study between Public and Private Hospitals

ASTRACT

The current study aimed to identify the quality of health services provided by the Omani health sector through the comparison between public and private hospitals in Dhofar Governorate, Oman. A questionnaire has been developed to collect data from 360 patients who received health services in one public Hospital (Sultan Qaboos) and three private Hospitals (Badr Al-Sama, Lifeline, and Al-Hakeeim). The data were analyzed using independent samples T-Test and One Way ANOVA. The results of the study showed that the quality levels of health services offered in private hospitals were better than public hospitals. The study results also reveled that there are significant differences between public hospitals and private hos

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Publication Date
Wed Apr 07 2021
Journal Name
Journal Of Legal Sciences
The role of constitutional judiciary in the protection of academic freedom in Iraq: Comparative study

Academic freedom is a human right, and if human rights are general rights, academic freedom is a special freedom for members of the academic community. Despite the modernity of the term "academic freedom", its content was not the result of the contemporary state of scientific academic bodies, That the development of the importance of this term coincided with the development of the exercise of public freedoms, and increased interest in and protection, so the number and expanded images of academic freedom, and was a manifestation of interest in this freedom to try to determine the content or what it is and pictures, The first of these guarantees is the supervision of the constitutionality of the laws, which are carried out through judicial

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