Time filter

Source Type

El-Sousy F.F.M.,Salman bin Abdulaziz University | El-Sousy F.F.M.,Electronics Research Institute of Egypt
IEEE Transactions on Industrial Informatics | Year: 2013

In this paper, an intelligent control system using recurrent wavelet-based Elman neural network (RWENN) for position control of permanent-magnet synchronous motor (PMSM) servo drive is proposed to achieve high precision tracking performance and to deal with the existence of uncertainties. The proposed intelligent optimal RWENN control system (IORWENNCS) incorporating an optimal controller, a RWENN controller and a robust controller. Based on the principle of optimal control, a position tracking controller is designed to minimize a quadratic performance index. In addition, a RWENN controller with accurate approximation capability is used to approximate a nonlinear function in the optimal control law. Moreover, a robust controller with adaptive bound estimation algorithm is proposed to confront the approximation error. The online adaptive control laws are derived based on the optimal control technique and Lyapunov stability analysis, so that the stability of the IORWENNCS can be guaranteed. Using the proposed control scheme, the position tracking performance is substantially improved and the robustness to uncertainties can be obtained as well. All control algorithms are implemented in a TMS320C31 DSP-based control computer. The simulation and experimental results confirm that the proposed IORWENNCS grants robust performance and precise tracking response regardless of load disturbances and PMSM uncertainties. © 2005-2012 IEEE. Source

Al-Saikhan F.I.,Salman bin Abdulaziz University
Saudi Journal of Ophthalmology | Year: 2013

The advances in gene therapy hold significant promise for the treatment of ophthalmic conditions. Several studies using animal models have been published. Animal models on retinitis pigmentosa, Leber's Congenital Amaurosis (LCA), and Stargardt disease have involved the use of adeno-associated virus (AAV) to deliver functional genes into mice and canines. Mice models have been used to show that a mutation in cGMP phosphodiesterase that results in retinitis pigmentosa can be corrected using rAAV vectors. Additionally, rAAV vectors have been successfully used to deliver ribozyme into mice with a subsequent improvement in autosomal dominant retinitis pigmentosa. By using dog models, researchers have made progress in studying X-linked retinitis pigmentosa which results from a RPGR gene mutation. Mouse and canine models have also been used in the study of LCA. The widely studied form of LCA is LCA2, resulting from a mutation in the gene RPE65. Mice and canines that were injected with normal copies of RPE65 gene showed signs such as improved retinal pigment epithelium transduction, visual acuity, and functional recovery. Studies on Stargardt disease have shown that mutations in the ABCA4 gene can be corrected with AAV vectors, or nanoparticles. Gene therapy for the treatment of red-green color blindness was successful in squirrel monkeys. Plans are at an advanced stage to begin clinical trials. Researchers have also proved that CD59 can be used with AMD. Gene therapy is also able to treat primary open angle glaucoma (POAG) in animal models, and studies show it is economically viable. © 2013 Saudi Ophthalmological Society, King Saud University. Source

Mohamed A.-B.A.,Assiut University | Mohamed A.-B.A.,Salman bin Abdulaziz University
Quantum Information Processing | Year: 2013

Quantum correlations, including entanglement and discord with its geometric measure in a three-qubit Heisenberg XY chain, with phase decoherence, are investigated when a nonuniform magnetic field is applied. When the qubits are initially in an unentangled state, the nearest neighbor pairwise correlations are destroyed by phase decoherence, but stationary correlations appear for next-to-neighbor qubits. With an inhomogeneous magnetic field, the stationary correlations appear for nearest neighbor qubits and they disappear for next-to-nearest neighbor qubits. But when the qubits are initially in an entangled state, an inhomogeneous magnetic field can enhance the stationary correlations of next-to-neighbor qubits, but it cannot do so for nearest neighbor qubits. The decoherence effect on stationary correlations is much stronger for next-to-nearest neighbor qubits than it is for nearest neighbor qubits. Finally, a uniform magnetic field can affect the correlations when the qubits are initially in an entangled state, but it cannot affect them when the qubits are initially in an unentangled state. © 2012 Springer Science+Business Media, LLC. Source

Ahmad S.,Salman bin Abdulaziz University
Egyptian Journal of Ear, Nose, Throat and Allied Sciences | Year: 2013

Objective: This study sought to determine causative microorganisms of chronic suppurative otitis media (CSOM) and to estimate their susceptibility to antibiotic agents. Materials and methods: One hundred sixty-four (164) patients with unilateral or bilateral active chronic suppurative otitis media were prospectively studied. They had chronic ear discharge and had not received any antibiotics for the previous 5. days. Swabs were taken from all patients, and sent to the Microbiology Department for processing. The specimens were cultured and the isolates were identified using standard microbiological techniques. The antibiotic susceptibilities of the isolates were determined with standard antibiotic discs using the Kirby-bauer disc diffusion method. Results: This study analyzes the causal organisms and their sensitivity to various antibiotics. The major organisms isolated were Methicillin sensitive Staphylococcus aureus [MSSA] (45.1%) followed by Pseudomonas aeruginosa (19.5%). The sensitivity of S. aureus (MSSA) was 79.7% to ciprofloxacin, 69% to cotrimoxazole, and 82.5% to gentamicin whereas the sensitivity of P. aeruginosa was 100% to ceftazidime, 84.4% to ciprofloxacin, 90.6% to gentamicin, and 78.1% to Piperacillin. Majority of the isolates of P. aeruginosa were completely resistant to polymixin B (71.9%) whereas 50% of S. aureus (MSSA) showed resistance to Ampicillin. All Methicillin resistant S. aureus (MRSA) isolates showed 100% resistance to Ampicillin, Augmentin and cephalothin. Among the available topical antibiotic preparations for use in the ear, we found gentamicin and ciprofloxacin as the best choices. Conclusion: The study of microbial pattern and their antibiotic sensitivity determines the prevalent bacterial organisms causing CSOM in the local area to start empirical treatment of otitis media and its complications for a successful outcome, and thus to prevent the emergence of resistant strains. © 2013 . Source

Elsabee M.Z.,Cairo University | Abdou E.S.,Egyptian Food Technology Research Institute | Abdou E.S.,Salman bin Abdulaziz University
Materials Science and Engineering C | Year: 2013

Chitosan is a biodegradable biocompatible polymer derived from natural renewable resources with numerous applications in various fields, and one of which is the area of edible films and coatings. Chitosan has antibacterial and antifungal properties which qualify it for food protection, however, its weak mechanical properties, gas and water vapor permeability limit its uses. This review discusses the application of chitosan and its blends with other natural polymers such as starch and other ingredients for example essential oils, and clay in the field of edible films for food protection. The mechanical behavior and the gas and water vapor permeability of the films are also discussed. References dealing with the antimicrobial behavior of these films and their impact on food protection are explored. © 2013 Elsevier B.V. Source

Discover hidden collaborations