Issue 1


Stability of Liquid Film with Negligible Viscosity

Hamsa D. Saleem

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 11-19
DOI: 10.33899/csmj.2005.164063

In this paper, we consider the stability analysis for a disturbed unsteady flow, which is two-dimensional incompressible flow in a symmetric film where the effect of viscosity can be neglected in comparison with inertia forces. The partial differential equations governing such flow are obtained from the Navier - Stokes equations and we obtain an analytic solution for those equations. The whole system is disturbed and we found the regions where the flow is stable or unstable.
 

New Hybrid CG Algorithm Based on PR and FR Steps

Abbas Y. Al-Bayati; Khalil K. Abbo; Asma M. Abdalah

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 27-38
DOI: 10.33899/csmj.2005.164065

In this paper, a new hybrid conjugate gradient algorithm is proposed for unconstrained optimization. This algorithm combines the desirable computation aspects of Polak-Ribière steps and useful theoretical features of Fletcher-Reeves CG-steps. Computational results for this algorithm are given and compared with those of the Fletcher and Polak standard CG methods showing a considerable improvement over the latter two methods.
 

New Method to Reduce the Size of Codebook in Vector Quantization of Images

Sahar K. Ahmed

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 53-62
DOI: 10.33899/csmj.2005.164067

The vector quantization method for image compression inherently requires the generation of a codebook which has to be made available for both the encoding and decoding processes. That necessitates the attachment of this codebook when a compressed image is stored or sent. For the purpose of improving the overall efficiency of the vector quantization method, the need arose for improving a means for the reduction of the codebook size.
In this paper, a new method for vector quantization is presented by which the suggested algorithm reduces the size of  the codebook generated in vector quantization. This reduction is performed by sorting the codewords of the codebook then the differences between adjacent codewords are computed. Huffman coding (lossless compression) is performed on the differences in order to reduce the size of the codebbook.
 

On Rings whose Simple Singular R-Modules are GP-Injective

Zubayda M. Ibraheem

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 63-67
DOI: 10.33899/csmj.2005.164068

In this work we give a characterization of rings whose simple singular right R-modules are Gp-injective. We prove that if R is a quasi-duo ring whose simple singular right R-modules are Gp-injective, then any reduced right ideal of R is a direct summand. We also consider that a zero commutative ring with every simple singular left R-module is Gp-injective
 

Stability Analysis for Steady State Solutions of Huxley Equation

Saad A. Manaa; Mohammad Sabawi

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 69-84
DOI: 10.33899/csmj.2005.164069

Stability analysis of steady state solutions of Huxley equation using Fourier mode stability analysis in two cases is investigated. Firstly when the amplitude is constant and secondly when the amplitude is variable and the results were found to be: The solutions and  are  always stable while the solutions  and  are conditionally stable. In the second case, a comparison between the analytical solution and the numerical solution of Galerkin method is done and the results are the same.
 
 

Numerical Solution and Stability Analysis of Huxley Equation

Saad A. Manaa; Mohammad Sabawi

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 85-97
DOI: 10.33899/csmj.2005.164070

The numerical solution of Huxley equation by the use of two finite difference methods is done. The first one is the explicit scheme and the second one is the Crank-Nicholson scheme. The comparison between the two methods showed that the explicit scheme is easier and has faster convergence while the Crank-Nicholson scheme is more accurate. In addition, the stability analysis using Fourier (von Neumann) method of two schemes is investigated. The resulting analysis showed that the first scheme is conditionally stable if  and the second scheme is unconditionally stable.
 
 

Superposition Method with the Principle of Multiple Shooting for Solving Stiff Linear Initial Value Problems

Basheer M.S. Khalaf; Suhaib A. Al-Tamr

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 11-26
DOI: 10.33899/csmj.2005.164071

The main objective of this paper is the development of a new technique for solving stiff Linear Initial Value Problems (IVPs) in Ordinary Differential Equations (ODEs), The new Technique consists of combining the linear superposition principle with the principle of Multiple shooting.
We have applied the new technique successfully for solving hard stiff IVPs. Also we have studied the ability of the new technique for controlling the stability of the numerical solution of IVPs and how the new technique prevents the accumulation of round off errors.
 

Controlling the Security Objects Properties for Networks in Windows 2000

Dhuha Basheer Abdullah; Abd-Alnaseer Ahmed

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 27-48
DOI: 10.33899/csmj.2005.164072

Information security occupies a wide area in designing network operating systems. Windows 2000 was of the operating systems that offered great interest for network security, so it is recently considered as the most important network operating system because of the high extended capabilities in network security embedded in it. This search is devoted to the study of the network security in windows 2000. A special program for controlling the security properties for the main objects of the Windows 2000 database (Active Directory) has been built. ActiveX Data Object (ADO) is used for searching the Active Directory and ADSI interface for accessing security principal accounts. This software presents the likelihood of accessing the security properties of these objects to the level of flags and bits in the data structure of security properties elements.
 

Integration Method with Backpropagation

Nidhal H. AL-Assady; Jamal S. Majeed; Shahbaa I. Khaleel

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 49-68
DOI: 10.33899/csmj.2005.164073

In this research, a new method is discovered (combined method) to accelerate the backpropagation network by using the expected values of source units for updating weights, we mean the expected value of unit by the sum of the output of the unit and its error term multiplied by the factor Beta to accelerate the algorithm and also adjust the value of learning coefficient continuously if the value of energy function E decreases the learning rate is increased by a factor , if the value of the energy function E increases , the value of the learning rate is decreased by a factor . To obtain the optimal weight with minimum iteration and minimum time, we applied a new method on many applications to prove the result of this method (pattern compression, encoding and recognition on Arabic, English digits and alphabetic.
 

Recognition English Letters Using Invariant Moment in Extracting Properties of Images

Hadia Saleh Abdullah

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 69-82
DOI: 10.33899/csmj.2005.164074

In this research, a study of printed English characters properties for Optical Character Recognition is done using the invariant moment method to evaluate the character properties due to it’s resistance against the rotation, scaling and shifting work. In this, also preprocessing the text and recognized it.The image text is segment often  two dissuasion methods are used to measure the distance between the moments of the new characters and the stored moments, this method is the Euclidean distance which gives high recognition factor.Due to the property of independence of the English characters, the evaluation of the seven moment of the printed character is so easy, so we evaluate the moments of English character in a different position and different size for each character by rotating the character from 45° to 360°. As a result, the invariant moment method has high ability for the recognition use, if its adopted in English Optical Character Recognition the recognition rate equals 85%.
 

Implementation of Object Relational Data Base Management on Depreciation System Using ORACL

Asmaa Yaseen Hammo; Alaa F. Saeed

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 83-98
DOI: 10.33899/csmj.2005.164075

This research implements concept of Object Relational DataBases Management System ORDBMS on depreciation system because it’s considered as a complex model. ORDBMS abstracts the level of writing system by adding data types defined by user (user define type UDT) which represents business objects, these objects are stored in database as a column on table or object table which can be accessed by using methods defined by user (user define function UDF). Object reference REFs is used instead of multiple relational between tables. Multiple data are implemented using collection data type (Varray, Nested table) without the need for extra tables. The application is programmed using oracle8 software because it has the propriety of an object relational database.
 

Fractal Dimension Calculation for the General Shapes of ‎Geographical Maps and Closed Curves

Rayan Yousif Alkhayat; Basil Younis Thanoon

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 99-114
DOI: 10.33899/csmj.2005.164076

This research includes building a software to calculate the Fractal Dimension of the general shapes of the borders of geographical maps as well as closed curves. Two methods are adopted for calculating fractal dimension: the first is the well-known Box Counting method and the second is Two-dimension Variation method , some treatments of the two methods are performed in order to qualify them for practical application and fitness for the use in digital images which are used for the representation of borders of maps and closed curves. Matlab 6.5 programming language was used for the implementation of this work, the map of the republic of Iraq was used as a case study for the given work.
 
 

Best Design for Courtyard Occupied Using Computer

Abdul Satar J. Abdul Latif; Abdul Aziz S. Khalil; Alyaa Moufaq Abdul Majeed Haleem

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 115-138
DOI: 10.33899/csmj.2005.164077

The courtyard occupied a great importance in the architectural constructions in olden times and recently, especially in the Arab and Islamic architecture, due to their large atmospheric benefits. In addition to the beauty which they add to these constructions especially in the hot and dry regions nevertheless, the sun has its large effects, +ve and –ve onto the atmosphere of these courtyards and then onto these constructions, and that obligates the architect to do a very complicated calculations and to keep on recalculating to determine these effects, and then to take into account in his design in order to reach the best design. For this reason, it is to be necessary to obtain a mechanical procedure, which enables the designer (the architect) to get the inclusion of these calculations quickly and precisely in order to save the effort, time and expense.
The system, which has been built, achieved these calculations quickly and precisely. This system includes a group of units which belong to a main menu to enable the user using it easily in order to obtain its calculation without a need for a perfect knowledge about (using) computer. Baghdad City has been selected as a pattern of geographical site in which the courtyard is situated.