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jeasiq-1824
Applying some hybrid models for modeling bivariate time series assuming different distributions for random error with a practical application
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Abstract

  Bivariate time series modeling and forecasting have become a promising field of applied studies in recent times. For this purpose, the Linear Autoregressive Moving Average with exogenous variable ARMAX model is the most widely used technique over the past few years in modeling and forecasting this type of data. The most important assumptions of this model are linearity and homogenous for random error variance of the appropriate model. In practice, these two assumptions are often violated, so the Generalized Autoregressive Conditional Heteroscedasticity (ARCH) and (GARCH) with exogenous variables (GARCHX) are applied to analyze and capture the volatility that occurs in the conditional variance of a linear model. Since time series observations rarely have linear or nonlinear components in nature or usually included together. Therefore, the main purpose of this paper is to employ the hybrid model technique according to Zhang methodology for hybrid models to combine the linear forecasts of the best linear model of ARMAX models and the nonlinear forecasts of the best nonlinear models of (ARCH, GARCH & GARCHX) models and thus increase the efficiency and accuracy of performance forecasting future values of the time series.

This paper is concerned with the modeling and building of the hybrid models (ARMAX-GARCH) and (ARMAX-GARCHX), assuming three different random error distributions: Gaussian distribution, Student-t distribution, as well as the general error distribution and the last two distributions were applied for the purpose of capturing the characteristics of heavy tail distributions which have a Leptokurtic characteristic compared to the normal distribution. This research adopted a modern methodology in estimating the parameters of the hybrid model namely the (two-step procedure) methodology. In the first stage, the parameters of the linear model were estimated using three different methods: The Ordinary Least Squares method (OLS), the Recursive Least Square Method with Exponential Forgetting Factor (RLS-EF), and the Recursive Prediction Error Method (RPM). In the second stage, the parameters of the nonlinear model were estimated using the MLE method and employing the numerical improvement algorithm (BHHH algorithm).

 

 

 

The hybrid models have been applied for modeling the relationship between the exogenous time series represented by the exchange rate and the endogenous time series represented by the unemployment rate in the USA for the period from (January 2000 to December 2017 i.e. 216 observations), and also the out-of-sample forecasts of unemployment rate in the last twelve values of (2018). The forecasting performance of the hybrid models and the competing individual model was also evaluated using the loss function accuracy measures (MAPE), (MAE), and the robust (Q-LIKE). Based on statistical measurements, the results showed the hybrid models improved the accuracy and efficiency of the single model. () hybrid model error whose conditional variance follows a GED distribution is the optimal model in modeling the bivariate time series data under study and more efficient in the forecasting process compared with the individual model and the hybrid model. This is due to having the lowest values for accuracy measures. Different software packages (MATLAB (2018a), SAS 9.1, R 3.5.2 and EViews 9) were used to analyze the data under consideration.

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Publication Date
Fri Dec 16 2022
Journal Name
Journal Of The College Of Languages (jcl)
MCD (LOS MARCADORES DISCURSIVOS) The pragmatic analysis of discourse markers (The argumentative texts of the ABC newspaper as a model): El análisis pragmático de los marcadores discursivos (Los textos argumentativos del periódico ABC como modelo)
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When writing a text, such as a newspaper article, various types of discourse markers are frequently used to group sentences into paragraphs and parts in order to establish a discourse with certain functions, such as coordination, orientation, emphasizing the concepts presented, etc. It should also be noted that this type of mark exists in both written and spoken language. Therefore, it is convenient to dedicate a chapter to these linguistic elements to clarify their use and their classification, which is mainly based on Jose Portolés (2001), as well as the main features, specifically their features (prosodic, morphological, semantic and pragmatic).

Resumen

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Publication Date
Wed Oct 17 2018
Journal Name
Journal Of Economics And Administrative Sciences
Implications of Financial Reporting Governance in rationalizing investors decisions In financial markets in light of An International Financial Reporting Standards (IFRS)/ An analytical study of a selected sample of the joint stock companies in Iraq
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The financial crises that occurred in South East Asia and America, and the discovery of the financial and administrative corruption that affected these companies, which led to the crisis. Since then, organizations and institutions interested in accounting have begun new ways to further rationalize the management of these companies. Hence the concept of governance, which means good governance. Al-Susiya confirmed its adoption of the financial reporting standards and adopted internal and external auditing for the purpose of increasing the reliability and credibility of the financial and reports that increase the confidence of investors in making their investment decisions in the financial markets The study dealt with the contributi

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Publication Date
Tue Jun 01 2021
Journal Name
Journal Of The College Of Languages (jcl)
Theoretical asp ects of trans lation of a lite rary text in the fram ework of lingu istic and cult ural analysis: Теоретические асп екты перевода художес твенного текста в рам ках лингвокультурологического ана лиза
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          The present art icle discusses the prob lems of understanding and translating the lingu istic and cult ural aspect of a foreign lite rary text. The article considers the trans lation process through the pr ism of cult ural orientation. In the process of transl ation, the nati onal cultural iden tity should be expressed to the max imum extent, through all me ans of expre ssion that include imagery and inton ation. In addi tion to the author's sty le, special atte ntion should al so be pa id to tro pes, phraseological uni ts, colloquial wo rds and dial&n

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Publication Date
Wed Aug 03 2022
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The adequacy of foreign reserves and their role in the stability of the exchange rate of the Iraqi dinar
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Many countries are very important in their interest not only in diversifying foreign reserves, but in determining and planning their volume in accordance with the goals set, namely facing potential external shocks, as the research aims to determine the extent of the strength of foreign reserves in the possession of the Central Bank in relation to every influential variable in the Iraqi economy. , in order to determine the minimum level of reserves that requires reconsideration of the exchange rate, as the research adopted the inductive analytical method in analyzing real (Quantitative data) for the research variables in the years of study, as the research adopted a set of analytical indicators approved by the International Moneta

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Publication Date
Wed Oct 01 2014
Journal Name
Journal Of Economics And Administrative Sciences
The Sources and Effects of Risks of Forms of Islamic Financing in the Islamic Branches of the Commercial Bank
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Proved Islamic banks in many countries where they are present, whether Muslim or non-Muslim in the wake of the global financial crisis, it is more efficient, profitable, and stable compared with the conventional banks, so went many of the worlds towards providing Islamic banking through Islamic windows to Besides financial services and products offered by the traditional, or the initiative to enter formulas Islamic finance is fully compliant with the principles and rules of Islamic law and is Brokerage basic function of conventional banks and Islamic alike ) and that means working on the mobilization of savings from surplus units and directed towards the financial units of the fiscal deficit) , which operates commercial banks

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Publication Date
Sat Jan 02 2021
Journal Name
Journal Of The College Of Languages (jcl)
Determining situational dimensions as a method of Equivalence in the source and target language in the translation of Russian and Arab: ( Понимание реальности ) средство полной эквивалентности текста оргинала и текста перевода на русском и арабском языках
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The present paper stresses the direct effect of the situational dimension termed as “reality” on the authors’ thoughts and attitudes. Every text is placed within a particular situation which has to be correctly identified by the translator as the first and the most important step for a good translation. Hence, the content of any word production reflects some part of reality. Comprehending any text includes comprehending the reality’s different dimensions as reflected in the text and, thus illuminating the connection of reality features.

Аннотация 

Исследование под названием  ((«Понимание реальности» средство полно

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Publication Date
Thu Apr 20 2023
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Synthesis a Novel Complexes of VO(II),Mn(II),Fe(II) ,Co(II), Ni(II), Cu(II)and Pt(IV) Derived from Schiff’s Base of Pyridoxal and 2-amino-4-nitrophenol and Study their Biological Activates
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This work describes the synthesis of novel ligand (H2L2) (4-((2-hydroxy-5-nitrophenyl)imino)methyl)-5(hydroxymethyl)-2methylpyridin-3-ol)  type (NOO) donor atoms. When it coordinates with metal ions[V2+,Mn2+,Fe2+,Co2+,Ni2+,Cu2+and Pt4+] with the general formula K2[M(L2)2].XH2O and K2[VO(L2)(OSO3)].H2O . This ligand can form tridentate structures. The ligand was synthesized from the reaction of pyridoxal hydrochloride with 2-amino-4-nitrophenol in ethanol (as a solvent) at a mole ratio of 1:1 and thoroughly mixed and refluxed for 6-8  hrs . The reaction

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Publication Date
Tue Aug 03 2021
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The role of the forensic accounting philosophy in the transparency and quality of financial statements: : An applied study on a sample of workers at the Trade bank of Iraq and the Gulf Commercial Bank in Babylon
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This research aims to identify the role that forensic accounting plays on the transparency and quality of the financial statements in trade bank of Iraq and the Gulf Commercial Bank in Babylon. This research came to address the problem that most financial institutions suffer from, which is represented by the lack of transparency and the quality of the financial statements issued in a manner. Annual also the manipulation and fraud in the financial data, which causes a big gap between that institutions and organizational stakeholders. According to the implementation of the research hypothesis and the objectives of the research, a questionnaire was prepared consisting of three axes, the first axis dealing with the demographic distri

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Publication Date
Mon Apr 04 2022
Journal Name
Journal Of Educational And Psychological Researches
The Effectiveness of a Proposed Study Unit Based on the Funds of Knowledge Theory in Developing the Attitudes Towards Cultural Identity and the Proposed Study Unit among Students of Basic Education in the Sultanate of Oman
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The present study aims to explore the effectiveness of a proposed study unit based on the funds of knowledge theory in developing the attitudes towards cultural identity and the proposed study unit. In order to achieve the goal of the study, the two researchers followed the quasi-experimental approach, where the study sample consisted of (28) female students of the fifth-grade at Al-Jeelah Basic Education School, Al-Dakhiliyah Governorate in the Sultanate of Oman. The data were collected by two scales: the first is a scale of attitudes towards cultural identity consisting of (26) items. The second was a scale of attitudes towards the proposed study unit, which consisted of (24) items. The results of the study revealed that the effect of

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Publication Date
Sat May 07 2016
Journal Name
International Journal Of Science And Research
Synthesis, Characterization and Antimicrobial Activity Studies of Mixed-1,10-phenanthroline- Mn(II),Co(II), Cu(II), Ni(II) and Hg(II) Complexes with Schiff Base[2,2'-(1Z,1'Z)-(biphenyl-4,4'- diylbis(azan-1-yl-1-ylidene))bis(methan-1-yl-1- ylidene)diphenol]
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Abstract: The M(II) complexes [M2(phen)2(L)(H2O)2Cl2] in (2:1:2 (M:L:phen) molar ratio, (where M(II) =Mn(II), Co(II), Cu(II), Ni(II) and Hg(II), phen = 1,10-phenanthroline; L = 2,2'-(1Z,1'Z)-(biphenyl-4,4'-diylbis(azan-1-yl-1-ylidene))bis(methan-1-yl-1- ylidene)diphenol] were synthesized. The mixed complexes have been prepared and characterized using 1H and13C NMR, UV/Visible, FTIR spectra methods and elemental microanalysis, as well as magnetic susceptibility and conductivity measurements. The metal complexes were tested in vitro against three types of pathogenic bacteria microorganisms: Staphylococcus aurous, Escherichia coli, Bacillussubtilis and Pseudomonasaeroginosa to assess their antimicrobial properties. From this study shows that a

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