Preferred Language
Articles
/
jeasiq-288
A Comparative Study of Some Methods of Estimating Robust Variance Covariance Matrix of the Parameters Estimated by (OLS) in Cross-Sectional Data
...Show More Authors

 

Abstract

The Classical Normal Linear Regression Model Based on Several hypotheses, one of them is Heteroscedasticity as it is known that the wing of least squares method (OLS), under the existence of these two problems make the estimators, lose their desirable properties, in addition the statistical inference becomes unaccepted table. According that we put tow alternative,  the first one is  (Generalized Least Square) Which is denoted by (GLS), and the second alternative is to (Robust covariance matrix estimation) the estimated parameters method(OLS), and that the way (GLS) method neat and certified, if the capabilities (Efficient) and the statistical inference Thread on the basis of an acceptable but this method requires knowledge and knowledge of the nature of the problem and the private model of the problem, whether the Heteroscedasticity otherwise, the method (GLS) become inappropriate. The second alternative is a matrix contrast common variation fortified it does not require prior knowledge of the nature of your problem model, it's also an easy way and by this method has met with popular and interest in more than two decades by researchers, that the estimated of Robust covariance matrix the estimated parameters method(OLS), shall be according to data that is handled type, and we have dealt with in this study, cross-sectional data where the problem of Heteroscedasticity in contrast may be contained therein(Heteroscedasticity- Consistent Covariance matrix Estimation) and symbolized by the (HCCME) and includes many ways, and we have dealt with in our study of these methods  

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Mon Dec 18 2017
Journal Name
Agronomy
A Case Study of Potential Reasons of Increased Soil Phosphorus Levels in the Northeast United States
...Show More Authors

Recent phosphorus (P) pollution in the United States, mainly in Maine, has raised some severe concerns over the use of P fertilizer application rates in agriculture. Phosphorus is the second most limiting nutrient after nitrogen and has damaging impacts on crop yield if found to be deficient. Therefore, farmers tend to apply more P than is required to satisfy any P loss after its application at planting. Several important questions were raised in this study to improve P efficiency and reduce its pollution. The objective of this study was to find potential reasons for P pollution in water bodies despite a decrease in potato acreage. Historically, the potato was found to be responsible for P water contamination due to its high P sensitivity a

... Show More
View Publication
Publication Date
Sat Mar 30 2002
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
A Study of Absorption Column with Single Bubble Cap Tray in the Production of Sodium Bicarbonate
...Show More Authors

View Publication Preview PDF
Publication Date
Sun Mar 02 2014
Journal Name
Baghdad Science Journal
We study the effect of Ultra violet rays (A-B) in treatment of Vitiligo (applied Therapy)
...Show More Authors

This research evaluated the effect of (UV)(400-320A)Hz(320-220B)Hz on the patient with vitiligo , using it with our new combing therapy that include the oral (Psorlene ) topical , meladinine solution applied on the Vitiligiousns Lesions , In edition to the instralesnional injection in the Vitiligiousns Lesions by long acting steroid (kenacort-A ) by aprecentage of (5%) , after that we expose the patient to UV . The ruslets of this way of treatment more effective by using of the UV rays in the treatment of vitiligo , while the previous treatment that used the UV ray with or with out the psorlene , the results were not effective on controlling of the Vitiligio diseases comparing by the treatment used in this research as it stop’s the sp

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Jan 01 2023
Journal Name
2nd International Conference On Mathematical Techniques And Applications: Icmta2021
Review of clustering for gene expression data
...Show More Authors

View Publication
Crossref
Publication Date
Wed Jan 01 2020
Journal Name
Journal Of Southwest Jiaotong University
IMPROVED STRUCTURE OF DATA ENCRYPTION STANDARD ALGORITHM
...Show More Authors

The Internet is providing vital communications between millions of individuals. It is also more and more utilized as one of the commerce tools; thus, security is of high importance for securing communications and protecting vital information. Cryptography algorithms are essential in the field of security. Brute force attacks are the major Data Encryption Standard attacks. This is the main reason that warranted the need to use the improved structure of the Data Encryption Standard algorithm. This paper proposes a new, improved structure for Data Encryption Standard to make it secure and immune to attacks. The improved structure of Data Encryption Standard was accomplished using standard Data Encryption Standard with a new way of two key gene

... Show More
Publication Date
Thu Sep 01 2016
Journal Name
Journal Of Engineering | University Of Baghdad
Correction Factor for Methods of Installation of Piles Group in Sandy Iraqi Soils
...Show More Authors

Many problems are facing the installation of piles group in laboratory testing and the errors in results of load and settlement are measured experimentally may be happened due to select inadequate method of installation of piles group. There are three main methods of installation in-flight, pre-jacking and hammering methods. In order to find the correction factor between these methods the laboratory model tests were conducted on small-scale models. The parameters studied were the methods of installation (in-flight, pre-jacking and hammering method), the number of piles and in sandy soil in loose state. The results of experimental work show that the increase in the number of piles value led to increase in load carrying capacity of piled raft

... Show More
Publication Date
Thu Sep 01 2016
Journal Name
Journal Of Engineering
Correction Factor for Methods of Installation of Piles Group in Sandy Iraqi Soils
...Show More Authors

Many problems are facing the installation of piles group in laboratory testing and the errors in results of load and settlement are measured experimentally may be happened due to select inadequate method of installation of piles group. There are three main methods of installation in-flight, pre-jacking and hammering methods. In order to find the correction factor between these methods the laboratory model tests were conducted on small-scale models. The parameters studied were the methods of installation (in-flight, pre-jacking and hammering method), the number of piles and in sandy soil in loose state. The results of experimental work show that the increase in the number of piles value led to increase in load carrying ca

... Show More
View Publication Preview PDF
Publication Date
Mon Feb 25 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Tax penalties and their effectiveness in reducing the creative accounting practices: An Empirical Study of the General Commission for Taxes
...Show More Authors

The research aims to study and definition of the concept of creative accounting and motives adopted by the management of companies to achieve their own goals and their impact on the reliability of the financial statements and the tax settling accounts and whether that tax administration is able to detect and limit the creative accounting practices and impose legal sanctions deterrent against companies The research has come to a set of conclusions, including:

  1. The administration motives in the use of creative accounting methods, some internal motives related to the interests of the administration in maximizing profits to increase incentives and rewards, others are external, such as the impact on stock prices or reduce the am

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Apr 23 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Preparation And Study Of Some Electrical Properties Of Mn-Ni Fe2O4
...Show More Authors

 In this study, Mn-Ni Ferrite was prepared by using two composites of manganese ferrite ( MnFe2o4 )  and Nicle Ferrite ( NiFe2O4) tested by X-Ray diffraction (XRD) method. The dielectric constant (𝜀̅) and the dielectric loss tangent (𝑡𝑎𝑛 𝛿) were studied for the ferrite system prepared at different frequencies (100, 200… and 5000 kHz). It was found that the values of (𝜀̅) and (𝑡𝑎𝑛 𝛿) decrease with the  increase of frequencies.

View Publication Preview PDF
Publication Date
Sat Jan 30 2016
Journal Name
Ibn Al-haitham J. For Pure & Appl. Sci.
Study of Some Structural and Optical Properties of AgAlSe2 Thin Films
...Show More Authors

The structural properties of ternary chalcopyrite AgAlSe2 compound alloys and thin films that prepared by the thermal evaporation method at room temperature on glass substrate with a deposition rate (5±0.1) nm s-1 for different values of thickness (250,500 and 750±20) nm, have been studied, using X-ray diffraction technology. As well as, the optical properties of the prepared films have been investigated. The structural investigated shows that the alloy has polycrystalline structure of tetragonal type with preferential orientation (112), while the films have amorphous structure. Optical measurement shows that AgAlSe2 films have high absorption in the range of wavelength (350-700 nm). The optical energy gap for allowed direct transition we

... Show More
Preview PDF