European Journal of Scientific Research

Volume 123 No 3
June, 2014

Effects of Computer Assisted Instruction on Iranian High Schools Students’ Achievement in Geography
Zohreh Abedi Kargiban and Maryam Naderi
This study investigated the effectiveness of computer-assisted instruction on students ‘achievement in geography in Iranian High Schools. In this regard, purposive sampling was used. They were randomly divided into two matched groups (experimental and control) with 34 and 32 participants each. The results of students were analyzed using ANCOVA to test the hypotheses. The geography achievement test includes 16 items of multiple-choice objective type, developed and validated for data collection. The geography achievement test was administered to students as pre-test and post-test. The result indicated that students who received computer assisted instruction, performed better than the control group. There also was significant difference between the post-test performance scores of students who received this instruction. Based on the findings, it was recommended that computer-assisted instruction should be encouraged for teaching and learning of geography.
Keywords: Computer Assisted Instruction, Geography, High School.

Design of C-Band Substrate Integrated Waveguide Band-Pass Filter
Ahmed Rhbanou, Seddik Bri and Mohamed Sabbane
This article presented the design of C-band filter by using substrate integrated waveguide (SIW) technique. His conception was made by two different topologies (SIW filter with iris and SIW filter with circular inductive post) on an Epoxy FR4 substrate. The structures of SIW filter are analyzed by the code HFSS. The simulated results have shown insertion-loss lower than 5 dB within 14% bandwidth around 5.245 GHz. The return loss is better than-20 dB between 4.95 GHz and 5.5 GHz. The compatibility with planar circuits is provided via a specific microstrip transition (microstrip stepped transition).
Keywords: Rectangular waveguide, substrate integrated waveguide, microwave filters, Transition, SIW-microstrip technology.

The Effects of Specific AhR-Ligands on T Helper Cells Polarization
Hana’a A. Abu-Rezq
Specific AhR-ligands were reported to play an important role in immune-regulation. The current review will focus mostly on the effects of activating AhR with different ligands in autoimmunity. AhR ligation with specific ligands can affect T-cell differentiation, through activation of CD4+Foxp3+ regulatory T-cells and down regulation of the pro-inflammatory T-helper 17 cells. Review findings showed the possibility of using the AhR to treat inflammatory and autoimmune diseases in mice, suggesting that, specific AhR-ligands could be used for immune regulation in pathogenesis of autoimmune diseases of human and mice.
Keywords: Aryl hydrocarbon receptor; T helper 17; T regulatory cells; autoimmune disease; immunoregulation.

Chromatic Polynomials of Polymer Amylose and Nucleotides
Azeez L. Jabir, Abdul Jalil M. Khalaf and Emad A. Jaffar
Let G be a simple graph andλ(G, λ) denotes the number of proper vertex colorings of with at most λ colours, which is for a fixed graph G, a polynomial in λ, which is called the chromatic polynomial of G. By using the chromatic polynomial of some specific graphs, we obtain the chromatic polynomials of some biochemical structures.

Applications of Mixed Chaotic Systems for Database Security
Eman. W. Boghdady, A. R. Shehata and M. A. Azem
There are four main Database (DB) security controls: access control, information flow control, inference control, and cryptographic. The cryptographic control is considered as the core for DB security, it secures the DB by encryption during storage and communications. Current cryptographic techniques are classified into two types: traditional classical cryptography using standard algorithms (DES, AES, IDEA, etc.) and chaos cryptography using continuous (Chau, Rossler, Lorenz, etc.) or discreet (Logistics, Henon, etc.) algorithms. The important characteristics of chaos are its extreme sensitivity to initial conditions of the system. In this paper, DB-security systems based on chaotic algorithms are proposed. The Pseudo Random Numbers Generators (PRNGs) from the different chaotic algorithms are implemented using Matlab and their statistical properties are evaluated using NIST and other statistical test-suits. Then, these algorithms are used to secure conventional DB as plaintext, where the statistical properties of the ciphertext are also tested. To increase the complexity of the PRNGs and to let pass all the NIST statistical tests, we propose two PRNGs: one based on two mixed chaotic Logistic maps and another based on two mixed chaotic Henon maps, where each chaotic algorithm is running side-by-side and starting from random independent initial conditions and parameters (encryption keys). The resulted hybrid PRNGs passed the NIST statistical test suit.
Keywords: DB Security, Encryption, chaotic algorithms, Matlab simulation, and NIST statistical tests.

Issues in Nigerian and African Church History, 1849 – 2009
Onah Augustine Odey
Few studies exist on the Northern Cross River State or what remains of Ogoja Province of Nigeria, either singly or as a culture area. Admittedly, this is the fate suffered by many small communities in the former Eastern Province of Nigeria of which the Old Ogoja Province forms an integral part.

Polyclonal and Monoclonal Antibody-Based Methods for Detection of Plant Viruses
Amal Souiri, Mustapha Zemzami, Saaid Amzazi and Moulay Mustapha Ennaji
Plant diseases caused by pathogens mainly viruses are of great economic importance. Virus’s infections are responsible for losses in crop yield and quality in all parts of the world. Plant viruses cannot be directly controlled by chemical application. Consequently, prevention based on early detection and identi?cation is the only effective measure to manage the plant virus disease. Many viruses are good antigens and this property has been widely exploited to produce specific antibodies that can be used for virus detection and for examining relationships between viruses. Hybridoma technology revolutionized antibody production and eliminated many problems associated with polyclonal antiserum. Therefore, monoclonal antibodies promise considerable improvement of virus diagnosis with regard to specificity, sensitivity and reproducibility, by integrating several serological tests.
Keywords: Plant viruses, Economic impact, Diagnosis, Antigens, Antibodies, Serological techniques.

A Security of Attribute Based Signature Scheme
Sattar J. Aboud
In the attribute typed signature scheme the user can sign a document with any predicate that is satisfied by his attributes issued from the attribute agency. Based on this assumption, the signature shows not to an identity of a user signed the document, other than the demand concerning the attributes underlying signer possesses. In attribute based signature, participants cannot forge signature with attributes they are not have even by conspiring. Alternatively, an authorized signer stays anonymous without a concern of revocation and is identical between the participants whose attributes convincing a predicate specified in a signature. Attribute based signature is functional in various uses for example, in anonymous authentication and attribute typed message schemes. In this paper, we describe the characteristics of security of certain attribute typed signature scheme. Also, we illustrate multiple attacks in a presented threshold attribute typed signature scheme. We show that a scheme is not protected, because it accepts the signer having keys for a number of attributes to make general forgery and create the signature that can suit a threshold for the set of attributes is not have. We then describe an overall attack of a scheme, such that a hacker can get an element of a private key and work as a key creating authority to produce the secret key for another user. We also discuss some illustrations of attacks to focus on the defects of this scheme.

Rough TOPSIS Hybrid Approach for Dam Site Selection
Shaaban M. Shaaban
One of the most important problems in water resources management is the earth dam site selection. It depends on a set of qualitative and quantitative factors, and they may even be in conflict with each other. This study aims to develop a multi-criteria decision making approach to locate the dam site. For this propose a hybrid rough set TOPSIS approach is proposed. Firstly the redundant attributes are eliminated using rough set theory, then the weights of the reduct attributes are calculated finally the technique for order preference by similarity to ideal solution (TOPSIS) is applied for ranking the dam location. The proposed technique avoids subjective influence of expert weights and provides the decision maker by a new way of objective evaluation about choosing allocation.
Keywords: Rough set; TOPSIS; Redundant attributes; Multi-criteria decision making (MCDM); Water resources management.

Assessment of Performance of Turbulence Models in the Numerical Simulation of Mach 1.4 Free Jet from a Convergent Divergent Nozzle
Mubarak A. K, Naveen S. Das and Tide P. S
In the present work four different turbulence models are employed for the numerical prediction of flow field of the supersonic free jet exiting from a convergent divergent nozzle. The predicted results are then compared with the corresponding values obtained from literature. The nozzle is modeled with impermeable and adiabatic wall for the simulation of the supersonic jet with a nozzle exit mach number of 1.4. The flow is assumed to be two dimensional, steady, compressible and turbulent. The grid and domain were selected after conducting grid/domain independent study. The equations governing the flow fields, namely the continuity, momentum and the energy equations are solved by means of a density based solver along with appropriate boundary conditions. The effects of turbulence are investigated by employing turbulence models, which in turn ensures the closure of RANS equations that govern the turbulent flow. The turbulent models involved in the present work are standard k-ε model, RNG k-ε model, realizable k-ε model and the SST k-ω model. The parameters of interest include the axial and radial profiles of velocity, temperature and density. The results predicted by the above turbulence models are plotted along with the corresponding values available in the literature. The comparison of the predicted values with the experimental data revealed that the SST k-ω model is the best suited turbulence model followed by the realizable k-ε model. The standard and RNG k-ε models gave comparatively over predicted results.
Keywords: Turbulence models; Supersonic jet; CFD Simulation.