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On The Computation Of The Maximum Uncertainty Volume Of Stable Polynomials, F.M. Al-Sunni

Sultan Qaboos University Journal For Science

In this paper we propose a non-linear optimization based approach for the computation of the stability region for uncertain polynomials. Both box of polynomials and diamond of polynomials are addressed. Examples are presented as an illustration.

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A Monte Carlo Method For Low Pressure Radio Frequency Discharges, Lahouaria Settaouti, Abderrahmane Settaouti

Sultan Qaboos University Journal For Science

There is increasing interest in glow discharges because of their importance to a large number of application fields, like the microelectronics industry, flat plasma display panel technology, the laser and light industry and analytical spectrochemistry. To improve the capabilities of rf glow discharges, a good understanding of the discharge physics is highly desirable. The typical calculated results include the radio frequency (rf) voltage, the electrical field distribution, the density of argon ions and electrons, the electron energy distribution function and information about the collision processes of the electrons with the Monte Carlo model. These results are presented throughout the discharge …

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Characterizations Of K- Semimetric Spaces, Abdul M. Mohamad

Sultan Qaboos University Journal For Science

In this paper, we prove, for a space X, the following are equivalent:1. X is a D1 space with a regular-Gδ-diagonal,2. X is a D2 space with a regular-Gδ-diagonal, 3. X is a semi-developable space with Gδ (3) -diagonal, 4. X is a D1-space with a Gδ(3)-diagonal, 5. X is a D2 -space with a Gδ(3)-diagonal, 6. X is a q, -space with a G*δ (2)-diagonal, 7. X is a semi-developable space with G*δ (2)-diagonal, 8. X is a semimetrizable, c-stratifiable space, 9. X is a c-Nagata -space, 10. X is a K-semimetrizable.

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Synchronization And Oscillator Death In Diffusively Coupled Lattice Oscillators, Adu A.M. Wasike

Sultan Qaboos University Journal For Science

We consider the synchronization and cessation of oscillation of a positive even number of planar oscillators that are coupled to their nearest neighbours on one, two, and three dimensional integer lattices via a linear and symmetric diffusion-like path. Each oscillator has a unique periodic solution that is attracting. We show that for certain coupling strength there are both symmetric and antisymmetric synchronization that corresponds to symmetric and antisymmetric non-constant periodic solutions respectively. Symmetric synchronization persists for all coupling strengths while the antisymmetric case exists for only weak coupling strength and disappears to the origin after a certain coupling strength.

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Steady State Analysis Of A Upfc As Voltage Regulator For Optimal Position In The Transmission Line, S. Ali Al-Mawsawi, Mohammed R. Qader

Sultan Qaboos University Journal For Science

It has recently been illustrated that the Unified Power Flow Controller (UPFC) installation location plays an important role in effecting nonlinearly in the UPFC steady state performance of the system. A Pulse Width Modulation (PWM) based on UPFC as a voltage regulator is modeled and analyzed to investigate the optimal position in the transmission line. From the study made in this paper, it is shown that the location of UPFC plays a significant part in effecting nonlinearly. It is also found from the simulation results that the distribution of the active and reactive power flows can be controlled by varying …

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Comparative Study Of Plasma Parameters In Olive Ridley (Lepidochelys Olivacea) And Hawksbill (Eretmochelys Imbricata) During Nesting, A.Y.A. Alkindi, I.Y. Mahmoud, J.L. Plude

Sultan Qaboos University Journal For Science

The aim of this study is to investigate the role of plasma level parameters during nesting activity and provide data potentially useful to future studies on the dynamics of reproductive and stress hormones in the most endangered sea turtle species in the world. Plasma parameters in the sea turtles, olive ridley (Lipodochelys oliveacea) and hawksbill (Eretmochelys imbricata) from Masirah Island, Oman, were analyzed relative to nesting stress. To date, no study has been conducted on plasma parameter levels in sea turtles during nesting. Field observations were conducted under ideal temperature conditions. At the time of sampling, there was no significant …

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Derivatized Pentadentate Macrocyclic Ligands And Their Transition Metal Complexes, Muhammad S. Khan, Nawal K. Al-Rasbi, Edwin C. Constable, Adrian R. Dale, Jack Lewis

Sultan Qaboos University Journal For Science

The reaction of the pendant hydroxyethyl group in the planar pentadentate macrocyclic ligand,1,11-bis(2’-hydroxyethyl)-4,8;12,16;17,21-trinitrilo-1,2,10,11-tetraazacyclohenicosa- 2,4,6,9,12,14,18,20-octaene (L2), derived from the condensation of 2,6-pyridinedialdehyde with 6,6’-bis(2’ hydroxyethylhydrazino) -2,2’-bipyridine (L1), has been investigated. Esterification reactions are facile, and the reaction of the hydroxyethyl-substituted macrocycle with thionyl chloride yields a chloroethyl derivative. Metal complexes of the new derivatized macrocyclic ligands L3-6having general formula ML3-6X2.nH2O (M = Mn, Fe, Co, Ni, Cu, Zn) are readily prepared.

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Effect Of The Fineness Of Artificial Pozzolana (Sarooj) On The Properties Of Lime-Pozzolana Mixes, Abdel Wahid Hago, Amer Ali Al-Rawas, Awadh Al-Sidairi

Sultan Qaboos University Journal For Science

Strength development of lime-pozzolana mortars is affected by the fineness of the pozzolan. This paper examines the effect of the fineness of artificial pozzolana on the strength development of lime-pozzolana mixtures. An artificial pozzolana produced by calcining clays from Oman was used in this study. The artificial pozzolana is locally known as “Sarooj”, and is currently being used in a big project for the restoration of historical monuments undertaken by the Omani Ministry of National Heritage and Culture. The artificial pozzolana was ground to various degrees of fineness, blended with hydrated lime with a ratio of 3:1, and the resulting …

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Mineralogy Of The Tertiary Clay Deposits In Makkah And Rabigh Quadrangles, West Central Arabian Shield, Saudi Arabia, M.H. Basyoni, M.A. El Askary, N.A. Saad, R.J. Taj

Sultan Qaboos University Journal For Science

The mineralogy of the Tertiary clay deposits in Makkah and Rabigh quadrangles was thoroughly investigated by X-ray diffraction and differential thermal and thermogravimetric analyses in addition to other techniques. Results show that the investigated samples are predominantly composed of montmorillonite (Ca++ and/or Mg++ rich variety) and kaolinite, associated with subordinate illite and minor chlorite. Mixed layer montmorillonite-illite is recorded only in two samples. The relative abundance of these minerals by X-ray diffraction analysis showed that the studied clay deposits are of three types. The first, which is the most common, is highly montmorillonitic, the second is made up of a …

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Metrization Of Weakly Developable Spaces, Abdul M. Mohamad

Sultan Qaboos University Journal For Science

In this note, we present metrization of weak developability.

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A Fluid Film Squeezed Between Two Parallel Plane Surfaces Subject To Normal Oscillations, E. A. Hamza

Sultan Qaboos University Journal For Science

We study the motion which results when a fluid film is squeezed between two parallel surfaces in relative motion. Particular attention is given to the special case where one surface is fixed and the other is impulsively accelerated from a state of rest to a state of sinusoidal oscillations in a direction normal to its plane. In addition to the presentation of analytic solutions which are based on the regular perturbation technique and on the linearised analysis of the resulting nonlinear partial differential equation, a numerical solution of the full nonlinear equation based on a finite-difference scheme is obtained. The …

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Surface Preparation Of Inas (110) Using Atomic Hydrogen, T.D. Veal, C.F. Mcconville, S.H. Al-Harthi

Sultan Qaboos University Journal For Science

Atomic hydrogen cleaning has been used to produce structurally and electronically damage-free InAs(110) surfaces. X-ray photoelectron spectroscopy (XPS) was used to obtain chemical composition and chemical state information about the surface, before and after the removal of the atmospheric contamination. Low energy electron diffraction (LEED) and high-resolution electron-energy-loss spectroscopy (HREELS) were also used, respectively, to determine the surface reconstruction and degree of surface ordering, and to probe the adsorbed contaminant vibrational modes and the collective excitations of the clean surface. Clean, ordered and stoichiometric InAs(110)-(1×1) surfaces were obtained by exposure to thermally generated atomic hydrogen at a substrate temperature as …

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Periodic Solutions Of A System Of Delay Differential Equations For A Small Delay, Adu A.M. Wasike, Wandera Ogana

Sultan Qaboos University Journal For Science

We prove the existence of an asymptotically stable periodic solution of a system of delay differential equations with a small time delay t > 0. To achieve this, we transform the system of equations into a system of perturbed ordinary differential equations and then use perturbation results to show the existence of an asymptotically stable periodic solution. This approach is contingent on the fact that the system of equations with t = 0 has a stable limit cycle. We also provide a comparative study of the solutions of the original system and the perturbed system. This comparison lays the ground for …

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Deletion Designs, Michael Kamau Gachii, John Wycliff Odhiambo, Anne Wachira

Sultan Qaboos University Journal For Science

In this paper a method of constructing a class of flexible single replicate factorial designs in blocks is given. Simple expressions for calculating loss of information on low order interactions is presented.

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Regression Estimator Using Double Ranked Set Sampling, Hani M. Samawi, Eman M. Tawalbeh

Sultan Qaboos University Journal For Science

The performance of a regression estimator based on the double ranked set sample (DRSS) scheme, introduced by Al-Saleh and Al-Kadiri (2000), is investigated when the mean of the auxiliary variable X is unknown. Our primary analysis and simulation indicates that using the DRSS regression estimator for estimating the population mean substantially increases relative efficiency compared to using regression estimator based on simple random sampling (SRS) or ranked set sampling (RSS) (Yu and Lam, 1997) regression estimator. Moreover, the regression estimator using DRSS is also more efficient than the naïve estimators of the population mean using SRS, RSS (when the correlation …

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Design Of All Optical Packet Switching Networks, Hussein T. Mouftah

Sultan Qaboos University Journal For Science

Optical switches and wavelength converters are recognized as two of the most important DWDM system components in future all-optical networks. Optical switches perform the key functions of flexible routing, reconfigurable optical cross-connect (OXC), network protection and restoration, etc. in optical networks. Wavelength Converters are used to shift one incoming wavelength to another outgoing wavelength when this needs to be done. Always residing in optical switches, they can effectively alleviate the blocking probability and help solve contention happening at the output port of switches. The deployment of wavelength converters within optical switches provides robust routing, switching and network management in optical …

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Intelligent Techniques For Power Systems Vulnerability Assessment, Mohamed A. El-Sharkawi

Sultan Qaboos University Journal For Science

With power grids considered national security matters, the reliable operation of the system is of top priority to utilities. This concern is amplified by the utility’s deregulation, which increases the system’s openness while simultaneously decreasing the applied degree of control. Vulnerability Assessment (VA) deals with the power system’s ability to continue to provide service in case of an unforeseen catastrophic contingency. Such contingencies may include unauthorized tripping, breaks in communication links, sabotage or intrusion by external agents, human errors, natural calamities and faults. These contingencies could lead to a disruption of service to part or all of the system. The …

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E-Business Development : A Strategic View, Saad Haj Bakry

Sultan Qaboos University Journal For Science

E-business is becoming increasingly important for countries, organizations and individuals, as it gives them efficiency, and as it integrates them together, and with the world at large. This paper aims at providing a strategic view of the development of e-business. It starts by identifying e-business, and by reviewing its current progress. It then presents an e-business development profile, that defines the various elements associated with it. Based on the profile, the paper then provides future development guidelines, and identifies recommended plans.

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Biological Effects Of Em Radiations From Mobile Phones, Adel A. Ali, Ahmed M. Al-Naamany

Sultan Qaboos University Journal For Science

Direct health effects could result following exposure to RF by thermal (heating effects). Recent Studies have shown that there are public fears on effects that can be caused mainly by holding mobile phones close to the body, or as a result of possible non-thermal effects from both phones and base stations. This paper offers an overview on the biological effects of electromagnetic radiation caused by mobile phones. Exposures of individuals to RF radiation from these sources will depend upon their proximity and may be above those from mobile phone base stations, although still well below guidelines. From a review of …

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Information Security Risks On A University Campus, Amer A. Al-Rawas, S. Millmore

Sultan Qaboos University Journal For Science

This paper is concerned with issues relating to security in the provision of information systems (IS) services within a campus environment. It is based on experiences with a specific known environment; namely Sultan Qaboos University. In considering the risks and challenges that face us in the provision of IS services we need to consider a number of interwoven subject areas. These are: the importance of information to campus communities, the types of information utilised, and the risk factors that relate to the provision of IS services. Based on our discussion of the risk factors identified within this paper, we make …

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Simulation Of M-Sequence’S Properties Through Matlab-Simulink, A. Ahmad, M. J. Al-Mushrafi, S. Al-Busaidi

Sultan Qaboos University Journal For Science

Based on an analytical study of the theory of m-sequences, a tool is developed to facilitate practicing engineers to either generate m-sequence for its application, or to test applied m-sequence, or both. The developed test–kit simulates all the properties of m-sequences including number of 1s and 0s, the run lengths, pulse periods as well as autocorrelation properties. This simplified tool is developed using MATLAB–SIMULINK with required codes as well as desired blocks. The model is cost-effective and the output files of the generated SIMULINK models can be utilized in any software program or simulation procedures.

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Development And Application Of Back-Propagation-Based Artificial Neural Network Models In Solving Engineering, Saleh Mohammed Al-Alawi

Sultan Qaboos University Journal For Science

Artificial Neural Networks (ANNs) are computer software programs that mimic the human brain's ability to classify patterns or to make forecasts or decisions based on past experience. The development of this research area can be attributed to two factors, sufficient computer power to begin practical ANN-based research in the late 1970s and the development of back-propagation in 1986 that enabled ANN models to solve everyday business, scientific, and industrial problems. Since then, significant applications have been implemented in several fields of study, and many useful intelligent applications and systems have been developed. The objective of this paper is to generate …

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Experimental Modeling Of Monolithic Resistors For Silicon Ics With A Robust Optimizer-Driving Scheme, Philippe Leduc, Didier Magnon, Fabrice Guitton

Sultan Qaboos University Journal For Science

Today, an exhaustive library of models describing the electrical behavior of integrated passive components in the radio-frequency range is essential for the simulation and optimization of complex circuits. In this work, a preliminary study has been done on Tantalum Nitride (TaN) resistors integrated on silicon, and this leads to a single p-type lumped-element circuit. An efficient extraction technique will be presented to provide a computer-driven optimizer with relevant initial model parameter values (the "guess-timate"). The results show the unicity in most cases of the lumped element determination, which leads to a precise simulation of self-resonant frequencies.

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Comparative Study Of Load Frequency Controller Designs For Interconnected Power Systems, M. Albadi, A. Awladthani, B. Alomeiri, K. Ellithy

Sultan Qaboos University Journal For Science

This paper presents a comparative study of three different load frequency (LF) controller designs for interconnected power systems. They are the conventional integral controller, a controller based on the pole-placement technique, and a controller based on optimal control law. Each controller has been designed to improve the dynamic response of system frequency and tie line power flow under a sudden load change. The results obtained using a MATALB computer program show the effectiveness of the LF controller designs. The results also show that the combined optimal controller with conventional integral controller can provide good damping to the system and reduce …

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Design Of Ultra Fast Rce Photodetectors For Optical Communications Systems, Joseph A. Jervase, Hadj Bourdoucen

Sultan Qaboos University Journal For Science

Two key parameters for RCE photodetectors that govern their suitability for ultrafast optical communication systems are considered. These are the quantum efficiency and the bandwidth efficiency product. A closed analytical form has been derived for quantum efficiency, which incorporates the structural parameters of the photodetector. Based on the simulation results, an optimization and design procedure for these photodetectors has been developed.

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Assessment Of The Electrical Systems Interconnection In The Arab World, M.H. Abderrazzaq

Sultan Qaboos University Journal For Science

The international trend of interconnecting electric power systems has two dimensions; economical and technical. Electric power systems in the Arab World are not only eligible, but in need for having a unified power grid. The potentials, status and conditions of the existing and future interconnections in this region are overviewed. The development of the six countries interconnection project, including the completed phase of Jordan-Egypt submarine link, is discussed in details. Finally, the main technical problems, which either faced the first stages of the project or expected to face the interconnected systems in the subsequent stages, are highlighted.

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Characteristic And Non-Characteristic Harmonics, Harmonic Cancellations And Relevant International Standards In Variable Speed Drives, Syed M. Islam

Sultan Qaboos University Journal For Science

This paper will present a review of characteristic harmonics in both single phase and three phase drive front end rectifiers, discuss recent research findings in identifying sources and production of non-characteristic harmonics and amplification of harmonic levels when the front end rectifiers are fed from non-ideal supply conditions. Significant amount of triplens may be generated due to unbalances in utility supply voltage wave form and anticipated harmonic levels may vary widely. The paper will also discuss international harmonic standards such as the AS 2279, IEEE 519, and IEC 61000 series applicable to rectifier loads. Finally, the paper will present techniques …

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Matlab And Pspice Dynamic Model Of Axial-Field Permanent-Magnet Motor, A.H. Al-Badi, A. Gastli

Sultan Qaboos University Journal For Science

In this paper a dynamic model of the axial-field, permanent-magnet machine will be discussed. The model may be used to study the transient response with the machine operating as a motor or as a generator. Experimental results are compared with Matlab/Simulink and Pspice predictions for a number of conditions, including the complete starting transient. Excellent correlation is obtained which validated both modeling approaches.

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A Modified Asynchronous Transfer Mode Fuzzy Policer, M.R.M. Rizk, H. Rashwan, A. Abdel Aziz

Sultan Qaboos University Journal For Science

A Modified Fuzzy policer for Asynchronous Transfer Mode is introduced. In a preceding fuzzy policer model the time window (time interval where ATM cells are accepted in the policer) is not synchronized with the source activity. In the proposed one, the time windows are not consecutive but are triggered by the first arriving cell. The modified policer gives good improvement to the selectivity, and minimizes the congestion over the path. This improvement can be significant for multiple channels.

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Joint Symbol And Frame Synchronization For Direct- Detection Optical Communication Systems, Eesa M. Bastaki, Harry H. Tan

Sultan Qaboos University Journal For Science

The problem of joint symbol and frame synchronization in direct-detection optical PPM communication systems under the assumption of known slot timing is considered here. The optimum maximum-likelihood (ML) and sub-optimum rules for this joint symbol and frame synchronization problem are derived. The reason of Georghiades's (1985) incorrect ML rule is discussed in this paper.

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Full-Text Articles in Entire DC Network

On The Computation Of The Maximum Uncertainty Volume Of Stable Polynomials, F.M. Al-Sunni

Sultan Qaboos University Journal For Science

A Monte Carlo Method For Low Pressure Radio Frequency Discharges, Lahouaria Settaouti, Abderrahmane Settaouti

Sultan Qaboos University Journal For Science

Characterizations Of K- Semimetric Spaces, Abdul M. Mohamad

Sultan Qaboos University Journal For Science

Synchronization And Oscillator Death In Diffusively Coupled Lattice Oscillators, Adu A.M. Wasike

Sultan Qaboos University Journal For Science

Steady State Analysis Of A Upfc As Voltage Regulator For Optimal Position In The Transmission Line, S. Ali Al-Mawsawi, Mohammed R. Qader

Sultan Qaboos University Journal For Science

Comparative Study Of Plasma Parameters In Olive Ridley (Lepidochelys Olivacea) And Hawksbill (Eretmochelys Imbricata) During Nesting, A.Y.A. Alkindi, I.Y. Mahmoud, J.L. Plude

Sultan Qaboos University Journal For Science

Derivatized Pentadentate Macrocyclic Ligands And Their Transition Metal Complexes, Muhammad S. Khan, Nawal K. Al-Rasbi, Edwin C. Constable, Adrian R. Dale, Jack Lewis

Sultan Qaboos University Journal For Science

Effect Of The Fineness Of Artificial Pozzolana (Sarooj) On The Properties Of Lime-Pozzolana Mixes, Abdel Wahid Hago, Amer Ali Al-Rawas, Awadh Al-Sidairi

Sultan Qaboos University Journal For Science

Mineralogy Of The Tertiary Clay Deposits In Makkah And Rabigh Quadrangles, West Central Arabian Shield, Saudi Arabia, M.H. Basyoni, M.A. El Askary, N.A. Saad, R.J. Taj

Sultan Qaboos University Journal For Science

Metrization Of Weakly Developable Spaces, Abdul M. Mohamad

Sultan Qaboos University Journal For Science

A Fluid Film Squeezed Between Two Parallel Plane Surfaces Subject To Normal Oscillations, E. A. Hamza

Sultan Qaboos University Journal For Science

Surface Preparation Of Inas (110) Using Atomic Hydrogen, T.D. Veal, C.F. Mcconville, S.H. Al-Harthi

Sultan Qaboos University Journal For Science

Periodic Solutions Of A System Of Delay Differential Equations For A Small Delay, Adu A.M. Wasike, Wandera Ogana

Sultan Qaboos University Journal For Science

Deletion Designs, Michael Kamau Gachii, John Wycliff Odhiambo, Anne Wachira

Sultan Qaboos University Journal For Science

Regression Estimator Using Double Ranked Set Sampling, Hani M. Samawi, Eman M. Tawalbeh

Sultan Qaboos University Journal For Science

Design Of All Optical Packet Switching Networks, Hussein T. Mouftah

Sultan Qaboos University Journal For Science

Intelligent Techniques For Power Systems Vulnerability Assessment, Mohamed A. El-Sharkawi

Sultan Qaboos University Journal For Science

E-Business Development : A Strategic View, Saad Haj Bakry

Sultan Qaboos University Journal For Science

Biological Effects Of Em Radiations From Mobile Phones, Adel A. Ali, Ahmed M. Al-Naamany

Sultan Qaboos University Journal For Science

Information Security Risks On A University Campus, Amer A. Al-Rawas, S. Millmore

Sultan Qaboos University Journal For Science

Simulation Of M-Sequence’S Properties Through Matlab-Simulink, A. Ahmad, M. J. Al-Mushrafi, S. Al-Busaidi

Sultan Qaboos University Journal For Science

Development And Application Of Back-Propagation-Based Artificial Neural Network Models In Solving Engineering, Saleh Mohammed Al-Alawi

Sultan Qaboos University Journal For Science

Experimental Modeling Of Monolithic Resistors For Silicon Ics With A Robust Optimizer-Driving Scheme, Philippe Leduc, Didier Magnon, Fabrice Guitton

Sultan Qaboos University Journal For Science

Comparative Study Of Load Frequency Controller Designs For Interconnected Power Systems, M. Albadi, A. Awladthani, B. Alomeiri, K. Ellithy

Sultan Qaboos University Journal For Science

Design Of Ultra Fast Rce Photodetectors For Optical Communications Systems, Joseph A. Jervase, Hadj Bourdoucen

Sultan Qaboos University Journal For Science

Assessment Of The Electrical Systems Interconnection In The Arab World, M.H. Abderrazzaq

Sultan Qaboos University Journal For Science

Characteristic And Non-Characteristic Harmonics, Harmonic Cancellations And Relevant International Standards In Variable Speed Drives, Syed M. Islam

Sultan Qaboos University Journal For Science

Matlab And Pspice Dynamic Model Of Axial-Field Permanent-Magnet Motor, A.H. Al-Badi, A. Gastli

Sultan Qaboos University Journal For Science

A Modified Asynchronous Transfer Mode Fuzzy Policer, M.R.M. Rizk, H. Rashwan, A. Abdel Aziz

Sultan Qaboos University Journal For Science

Joint Symbol And Frame Synchronization For Direct- Detection Optical Communication Systems, Eesa M. Bastaki, Harry H. Tan

Sultan Qaboos University Journal For Science