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State-Of-The-Art Methods For Electric Power Systems Voltage Stability Analysis, T.M. Al-Khusaibi, K. A. Ellithy, M.R. Irving Apr 2025

State-Of-The-Art Methods For Electric Power Systems Voltage Stability Analysis, T.M. Al-Khusaibi, K. A. Ellithy, M.R. Irving

Sultan Qaboos University Journal For Science

This paper presents a literature survey on the subject of voltage stability analysis of power systems. The survey describes several published methods and techniques used to determine voltage stability indices. These indices predict proximity to voltage instability and collapse problems. The Q-V and P-V curves; singular value decomposition; modal analysis; test function; reduced determinant; loading margin by multiple power flow solutions; local load margins; thevenin/load impedance; and energy function are the methods which have been decribed in the paper. The methods described are based on the original work that first proposed them. They are based on the power-flow system model, …

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Modeling Flow And Transport In Unsaturated Porous Media: A Review, H.H. Al-Barwani, M. Al-Lawatia, E. Balakrishnan, A. Purnama Apr 2025

Modeling Flow And Transport In Unsaturated Porous Media: A Review, H.H. Al-Barwani, M. Al-Lawatia, E. Balakrishnan, A. Purnama

Sultan Qaboos University Journal For Science

Underground water is a vital natural resource and every effort should be made to understand ways and means of efficiently using and managing it. The unsaturated zone, bounded at its top by the land surface and below by the water table, is the region through which water, together with pollutant carried by the water, infiltrates to reach the groundwater. Therefore, various processes occurring within the unsaturated zone play a major role in determining both the quality and quantity of water recharging into the groundwater. Classical methods of predicting water flow and contaminant transport processes in unsaturated porous media are generally …

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Homochiral Acyl Isocyanates As Diagnostic Nmr Probes For The Enantiomeric Purity Of Chiral Alcohols, Gregory H. P. Roos, Anthony R. Donovanb Apr 2025

Homochiral Acyl Isocyanates As Diagnostic Nmr Probes For The Enantiomeric Purity Of Chiral Alcohols, Gregory H. P. Roos, Anthony R. Donovanb

Sultan Qaboos University Journal For Science

The first reported acyl and sulfonylisocyanates were developed and tested in reactions with chiral alcohols to afford diastereomeric carbamates. NMR analysis of these investigates the chemical shift discrimination that would allow these activated isocyanates to be used as diagnostic probes of enantiomeric purity.

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Ultrastructural Changes In The Epithelium Of The Stomach Of Aphanius Dispar (Cyprinodontidae), Due To Stress From Starvation, Taher A. Ba-Omar, Reginald Victor Apr 2025

Ultrastructural Changes In The Epithelium Of The Stomach Of Aphanius Dispar (Cyprinodontidae), Due To Stress From Starvation, Taher A. Ba-Omar, Reginald Victor

Sultan Qaboos University Journal For Science

Ultrastructural changes in the epithelium of the stomach of Aphanius dispar, a cyprinodont fish, due to starvation have been described. The changes in the epithelium after 24, 48, 72, 96, and 120 hours have been discussed. The degeneration of the epithelial cells commenced after 24 hours and steadily progressed till 96 hours at which the maximum change was observed. Changes in response to starvation include the disappearance of lipid droplets, mitochondrial damage, goblet cells degeneration, morphological aberration of the nuclei and overall abnormalities in the structural integrity of the rugae. This study confirms that stress due to starvation causes significant …

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Earthquake Response Of A Historical Castle, Mohammed Qamaruddin, Ali Salim Al-Harthy Apr 2025

Earthquake Response Of A Historical Castle, Mohammed Qamaruddin, Ali Salim Al-Harthy

Sultan Qaboos University Journal For Science

The earthquake hazard potential in the Sultanate of Oman is considered real as there are several reports of felt earthquakes in the Sultanate of Oman during the period from years 977 to 1998, although no damage to the existing structures has been reported due to earthquakes. In Oman, seismic zoning map and other basic data are required for the development of a standard code for seismic design of structures. In this paper, seismic response of a historical Nizwa castle in Oman is assessed employing the methodology of Uniform Building Code (UBC, 1994). Also, in the absence of data pertaining to …

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Electromagnetic Modeling Of The Propagation Characteristics Of Satellite Communications Through Composite Precipitation Layers, Part1: Mathematical Formulation, H.M. Al-Rizzo, And Department Of Electrical And Electronics Engineering, College Of Engineering, Sultan Qaboos University, P.O. Box 33, Al Khod 123, Muscat, Sultanate Of Oman., H.T. Al-Hafid, J.M. Tranquilla Apr 2025

Electromagnetic Modeling Of The Propagation Characteristics Of Satellite Communications Through Composite Precipitation Layers, Part1: Mathematical Formulation, H.M. Al-Rizzo, And Department Of Electrical And Electronics Engineering, College Of Engineering, Sultan Qaboos University, P.O. Box 33, Al Khod 123, Muscat, Sultanate Of Oman., H.T. Al-Hafid, J.M. Tranquilla

Sultan Qaboos University Journal For Science

A systematic and general formulation of a Propagation Simulation Program (PSP) is developed for the coherent field of microwave and millimeter wave carrier signals traversing intermediate layered precipitation media, taking into account the random behavior of particle size, orientation, shape and concentration distributions. Based on a rigorous solution of the volumetric multiple-scattering integral equations, the formalism offers the capability of treating the potential transmission impairments on satellite-earth links and radar remote sensing generated by composite atmospheric layers of precipitation in conjunction with the finite polarization isolation of dual-polarized transmitting and receiving antennas. A multi-layered formulation is employed which encompasses an …

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Voltage Stability Analysis Of Muscat Power System During Summer Weather Conditions, K. Ellithy, A. Gastli, S. Al-Alawi, A. Al-Hinai, Z. Al-Abri Apr 2025

Voltage Stability Analysis Of Muscat Power System During Summer Weather Conditions, K. Ellithy, A. Gastli, S. Al-Alawi, A. Al-Hinai, Z. Al-Abri

Sultan Qaboos University Journal For Science

A systematic and general formulation of a Propagation Simulation Program (PSP) is developed for the coherent field of microwave and millimeter wave carrier signals traversing intermediate layered precipitation media taking into account the random behavior of particle size, orientation, shape and concentration distributions. Based on a rigorous solution of the volumetric multiple-scattering integral equations, the formalism offers the capability of treating the potential transmission impairments on satellite-earth links and radar remote sensing generated by composite atmospheric layers of precipitation in conjunction with the finite polarization isolation of dual-polarized transmitting and receiving antennas. A multi-layered formulation is employed which encompasses an …

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Electromagnetic Modeling Of The Propagation Characteristics Of Satellite Communications Through Composite Precipitation Layers, Part Ii: Results Of Computer Simulations, H.M. Al-Rizzo, H.T. Al-Hafid, J.M. Tranquilla Apr 2025

Electromagnetic Modeling Of The Propagation Characteristics Of Satellite Communications Through Composite Precipitation Layers, Part Ii: Results Of Computer Simulations, H.M. Al-Rizzo, H.T. Al-Hafid, J.M. Tranquilla

Sultan Qaboos University Journal For Science

A versatile Propagation Simulation Program (PSP) is developed to assess the degrading effects caused by the concurrent occurrences of an arbitrary mixture of ice plates and needles, melting snow and raindrops which may impede the reliability of dual-polarized satellite communications systems carrying independent channels on a single radio path. Specifically, results are presented for the Cross Polarization Discrimination (XPD) due to ice and rain, differential attenuation, Da, and differential phase shift, Df, due to rain and average specific attenuation, a, and phase shift, f , due to the melting layer at hitherto unconsidered frequencies. The inclusion of an ice-cloud medium …

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Simple Monte Carlo Cellular Models For Surface Evolution, H. H. Al-Barwani, A. Purnama Apr 2025

Simple Monte Carlo Cellular Models For Surface Evolution, H. H. Al-Barwani, A. Purnama

Sultan Qaboos University Journal For Science

Monte Carlo cellular simulations are described for some simple surface evolution models. Surface growth is simulated by adding new cells to the surface. The bonding of a new cell arriving to a site on the surface depends on the number of cells present around that site; new cells are more likely to stick at sites with the fewest missing surrounding cells. Applications are given for simulating the propagation of a flame front and the formation of surface landforms; and the (anisotropic) growth of a crystal, where the surface may grow more rapidly in one direction than others.

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Flow Past A Rotating Circular Cylinder And A Rotlet Using The Finite-Difference Method, T. B. A. El Bashir Apr 2025

Flow Past A Rotating Circular Cylinder And A Rotlet Using The Finite-Difference Method, T. B. A. El Bashir

Sultan Qaboos University Journal For Science

In this paper the flow generated by a rotlet in the presence of a circular cylinder is considered. We introduce a transformation which simplifies the equations and boundary conditions. We use the finite-difference method to obtain results in excellent agreement with all the available analytical results. Results are presented for Reynolds numbers, based on the diameter of the cylinder, in the range 0 ≤ Re ≤ 20 and the rotational parameter, α , in the range 0 ≤α ≤ 3 and strength of rotlet, β , in the range 0 ≤ β ≤ 3 . The results are found to …

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Surface Plasmons For Probing Optical Data Of Multi- Layered Thin Films, A. Rais, A. Sellai Apr 2025

Surface Plasmons For Probing Optical Data Of Multi- Layered Thin Films, A. Rais, A. Sellai

Sultan Qaboos University Journal For Science

In this paper, we show how optical excitation of surface plasmons (SPs) can be used to obtain optical and geometrical parameters of specific layers in multi-layered thin film systems. The optimum coupling phenomenon between incoming p-polarized light and SPs appears as a minimum in the reflectance that is calculated using a standard matrix formalism. The sensitive dependence of the reflectance minimum on optical and geometrical parameters suggests that they can be determined accurately by fitting the measured attenuated total reflectance (ATR) to the matrix-calculated reflectance using the Simplex minimization method. The procedure is applied to the multi-layered system: Prism / …

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A Generalization Of The Hypergeometric Distribution, E.K. Elsheikh, A. Benmerzouga Apr 2025

A Generalization Of The Hypergeometric Distribution, E.K. Elsheikh, A. Benmerzouga

Sultan Qaboos University Journal For Science

In this paper we introduce a modification of the hypergeometric distribution that caters for the case when the sampling scheme favours the inclusion of units of one of the two types involved, as opposed to the hypergeometric distribution under which all samples are equally likely. The properties of the resulting distribution, termed the generalized hypergeometric, are studied, including the derivation and numerical assessment of a normal approximation of the distribution.

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Solvent Extraction Of Uranium (Vi) By Didodecylphosphoric Acid, Khaled Mousa, Fawwaz Khalili Apr 2025

Solvent Extraction Of Uranium (Vi) By Didodecylphosphoric Acid, Khaled Mousa, Fawwaz Khalili

Sultan Qaboos University Journal For Science

Solvent extraction of uranium(Vl) ion from perchlorate solution using didodecylphosphorie acid, DDPA, in toluene diluent was studied. The effects of stripping nitric acid concentration, stripping time, extraction time, DDPA concentration, pH, ionic strength, supporting electrolyte and temperature on the extraction processes have been studied. From the distribution coefficient values at different temperatures, the enthalpy, the free energy and the entropy changes associated with the extraction processes were determined. The composition of the complex formed was established to be UO2(CLO4)(HR2)(HR)2 where, (HR)2 represents the dimer of DDPA.

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Spermatogenesis And Spermiogenesis Of The Aphanius Dispar, Taher A. Ba-Omar Apr 2025

Spermatogenesis And Spermiogenesis Of The Aphanius Dispar, Taher A. Ba-Omar

Sultan Qaboos University Journal For Science

Light and transmission electron microscopy were used to study the structure of various stages of germ cells of the Aphanius dispar (Ruppell l828) in Oman. A dispar testes were of cystic type. Different stages of spermatogonia, spermatocytes and spermatids were observed within the cysts. Each cyst is occupied by a group of germ cells almost all in the same stage. The morphology and ultra structure of the nuclei and cytoplasmic organelles of the germ cells are described. Some flagella possessing lateral side fins and some biflagellated spermatozoa were seen.

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Computer-Aided Design For Estimating Foundation Uplift On Expansion Soils, Adnan A. Basma, Amer Ali Al-Rawas Apr 2025

Computer-Aided Design For Estimating Foundation Uplift On Expansion Soils, Adnan A. Basma, Amer Ali Al-Rawas

Sultan Qaboos University Journal For Science

This work presents a methodology to determine in-situ heave of foundations due to soil expansion. A total of 206 soil specimens from a semi-arid region (lrbid city in northern Jordan) were tested in the laboratory to produce a model for predicting the swell percent, SP. The results indicate that SP is strongly dependent on the placement conditions (initial water content and dry unit weight), clay content of the soil and the initial applied pressure. Utilizing this model, an Advanced BASIC computer program was written to evaluate in-situ heave. It was verified using actual field data: The program provides a Simple …

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A New Record Of Hydroptila Cruciata Ulmer In Southern Oman With Notes On Its Larval Biology, R. Victor Apr 2025

A New Record Of Hydroptila Cruciata Ulmer In Southern Oman With Notes On Its Larval Biology, R. Victor

Sultan Qaboos University Journal For Science

Fourth and fifth instar larvae of a hydroptilid richoptcran, Hydroprtila Ulmer 1912 were collected in the Sultanate of Oman for the first time. The fifth instar larva constructs a purse-case With filamentous algae. Notes on the habitat characteristics and the larval biology of this species are given.

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An Investigation Into The Traditional Method Of Production Of Omani Sarooj, A. W. Hago, Amer Ali Al-Rawas Apr 2025

An Investigation Into The Traditional Method Of Production Of Omani Sarooj, A. W. Hago, Amer Ali Al-Rawas

Sultan Qaboos University Journal For Science

In the past, sarooj had been used as the basic cementing material with which the A flaj system (the irrigation system used in Oman) was built. Worldwide, materials like sarooj existed and were known for their good impermeability and long durability. For this reason it was extensively used in hydraulic structures. Even in this century and with the ready availability of Portland cements, special plants were erected to produce materials like sarooj for major dams in the world. In the process of hydration In sarooj-lime mixes or in sarooj-cement mixes free lime is released which causes distress through the expansion …

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A Computer Aided Learning Tool For Readers, Sane M. Yagi, Saad Harous Apr 2025

A Computer Aided Learning Tool For Readers, Sane M. Yagi, Saad Harous

Sultan Qaboos University Journal For Science

A bilingual piece of software has been developed to cultivate student speed and critical reading abilities by expanding their visual span, improving their eye movement, reducing their visual regression, developing their stock of vocabulary, and by honing their skimming, scanning, and critical understanding skills. This paper overviews the software, explains its educational value for language teaching, and experimentally demonstrates its utility.

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Experimental Investigation And Failure Analysis Of Fastened Grp Under Bending Using Finite Element Method And Artificial Neural Networks, C. Seibi Abdennour, M. Al-Alawi Apr 2025

Experimental Investigation And Failure Analysis Of Fastened Grp Under Bending Using Finite Element Method And Artificial Neural Networks, C. Seibi Abdennour, M. Al-Alawi

Sultan Qaboos University Journal For Science

This paper presents a novel approach that predicts the strength and failure modes of jointed Glass Reinforced Polyester (GRP) samples under bending using Finite Element Method (FEM) and Artificial Neural Network (ANN). The mechanical behavior of fastened glass fiber reinforced plastics composites under bending have been experimentally investigated. Samples were obtained from Amiantit Oman, a manufacturing company operating in Russail Industrial Zone in the Sultanate of Oman. The experimental program involved the conduct of three point bending tests as well as bending tests of mechanically fastened joints under static loads. The experimental results showed that the dimensions of the specimen …

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Bmoa Characterization With Families Of Cauchy Transforms, Yusuf Abu Muhanna, El-Bachir Yallaoui Apr 2025

Bmoa Characterization With Families Of Cauchy Transforms, Yusuf Abu Muhanna, El-Bachir Yallaoui

Sultan Qaboos University Journal For Science

In this paper we prove a number of results on Cauchy transforms of generalized type given by Borel measures supported on the class of analytic functions mapping the unit disc into the unit desk.

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Applying Halstead's Metric To Oberon Language, Fawaz Ahmed Masoud Apr 2025

Applying Halstead's Metric To Oberon Language, Fawaz Ahmed Masoud

Sultan Qaboos University Journal For Science

Oberon is a small, simple and difficult programming language. The guiding principle of Oberon was a quote from Albert Einstein: "Make it as simple as possible, but not simpler". Oberon language is based on few fundamental concepts that are easy to understand and use. It supports two programming paradigms: the procedural paradigm, and the object-oriented paradigm This paper provides the application of Halstead's software science theory to Oberon programs. Applying Halstead's metric to the Oberon language has provided the analysis and measurements for module and within module maintenance complexity of programs written in Oberon. This type of analysis provides a …

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On The Excitation Of Instability Waves In Plane Poisuille Flow By A Concentrated Source At The Wall, Ayman Al-Maaitah Apr 2025

On The Excitation Of Instability Waves In Plane Poisuille Flow By A Concentrated Source At The Wall, Ayman Al-Maaitah

Sultan Qaboos University Journal For Science

The paper addresses the excitation of instability waves in plane Poiseuille flow by means of a concentrated source at the wall. The aim of this paper is to investigate the relation between the source amplitude and the excited wave amplitude for various flow and source parameters .The source is modeled by a time harmonic Dnae function and the generated disturbance is investigated By applying Founrier transform on the resulting linearized Navier-Stokes equation in the streamwise direction, the problem is resolved using inverse Fourier transform and the residue theorem. The theoretical formulation explains some observations by previous experiments on similar cases …

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Determination Of Ascorbic Acid In Oman Citrus Fruits, Ks.M.Z. Al-Kindi, A.O. Abdelnour, Rahma S. Al-Siyabi Apr 2025

Determination Of Ascorbic Acid In Oman Citrus Fruits, Ks.M.Z. Al-Kindi, A.O. Abdelnour, Rahma S. Al-Siyabi

Sultan Qaboos University Journal For Science

Omani citrus fruits were analyzed for their Vitamin C (ascorbic and AA) content by a titration method involving N-bromosuccinimide (NBS) as an oxidizing agent and by high performance liquid chromatography. Vitamin C content was also determined after storage at different temperatures. Vitamin C contents of the fruits were found to lie within the values reported in the literature.

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Mycoflora And Mycotoxigenic Moulds Of Pistachio Nuts For Human Consumption In The Sultanate Of Oman, A. E. Elshafie, N. S. Al-Shally Apr 2025

Mycoflora And Mycotoxigenic Moulds Of Pistachio Nuts For Human Consumption In The Sultanate Of Oman, A. E. Elshafie, N. S. Al-Shally

Sultan Qaboos University Journal For Science

Mycoflora of 75 cans of different batches and brands of pistachio nuts purchased in the Sultanate of Oman was studied. A number of fungi were isolated, with percentages of contaminated nuts [average between brands ] as follows: Aspergillus niger 14.8%, Penicillium spp. 13.6%, A flavus 9.7%, A nidulans 1.6%, and < l % for Cladosporium cladosporoides, Alternaria alternata , A ochraceeus and Ulocadium consortiale. Significant differences were found among the batches and brands contaminated by A flavus. A flatoxin B, was found only in one sample out of 1.5 assayed at a level of 2 ug/kg.

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A Comparative Analysis And Prediction Of Traffic Accident Causalities In The Sultanate Of Oman Using Artificial Neural Networks And Statistical Methods, Galal A. Ali, Saleh M. Al-Alawi, Charles S.Bakheit Apr 2025

A Comparative Analysis And Prediction Of Traffic Accident Causalities In The Sultanate Of Oman Using Artificial Neural Networks And Statistical Methods, Galal A. Ali, Saleh M. Al-Alawi, Charles S.Bakheit

Sultan Qaboos University Journal For Science

Traffic accidents are among the major causes of death in the Sultanate of Oman This is particularly the case in the age group of I6 to 25. Studies indicate that, in spite of Oman's high population-per-vehicle ratio, its fatality rate per l0,000 vehicles is one of the highest in the world. This alarming Situation underlines the importance of analyzing traffic accident data and predicting accident casualties. Such steps will lead to understanding the underlying causes of traffic accidents, and thereby to devise appropriate measures to reduce the number of car accidents and enhance safety standards. In this paper, a comparative …

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Effect Of Wind Environment On The Response Of Buildings In Oman, Mohammed Qamaruddin, Salem K. Al-Oraimi Apr 2025

Effect Of Wind Environment On The Response Of Buildings In Oman, Mohammed Qamaruddin, Salem K. Al-Oraimi

Sultan Qaboos University Journal For Science

An investigation has been carried out to study the effect of the wind parameters on the response of multistory buildings subjected to wind induced forces. This study is concerned with the wind response of the buildings located at six building sites in Sohar, Thumrait and Saiq regions of Oman. A typical plan of multistory-framed building has been chosen for the present investigation. The Wind and the other related data appropriate to these regions have been used in the analysis. It turns out from the present study that the response of the building located at a Site in a country terrain …

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Quantitative Analysis Of Clay Minerals Using X-Ray Diffraction Technique. Part 1, Amer Al-Rawas, Hector Sutherland, A.W. Hago, Adnan Basma, Badar Al-Shihi Apr 2025

Quantitative Analysis Of Clay Minerals Using X-Ray Diffraction Technique. Part 1, Amer Al-Rawas, Hector Sutherland, A.W. Hago, Adnan Basma, Badar Al-Shihi

Sultan Qaboos University Journal For Science

Qualitative and quantitative analysis of clay minerals are important in the evaluation of the swelling potential of expansive soils A relatively simple method for the quantification of clay minerals of Al-Khod (Northern Oman) using an X-ray diffraction method is described in detail in this paper. The method is based on the additions of known internal standards to the clay sample. The clay investigated in this study contained montmorillonite, palygorskite, illtte and kaolinite. Internal standards of these minerals were mixed with the clay at different proportions and intensities of reflected peak areas were measured. It was found that the peak areas …

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Constructing Node-Disjoint Routes In K-Ary N-Cubes, Khaled Day, Abdel Elah Al-Ayyoub Apr 2025

Constructing Node-Disjoint Routes In K-Ary N-Cubes, Khaled Day, Abdel Elah Al-Ayyoub

Sultan Qaboos University Journal For Science

In this paper, a method for constructing node-disjoint (parallel) paths in k-ary n-cube interconnection networks is described. We start by showing in general how to construct parallel paths in any Cartesian product of two graphs based on known paths in the factor graphs. Then we apply the general result to build a complete set of parallel paths (i.e., as many paths as the degree of the network) between any two nodes of a k-ary n-cube which can be viewed as the Cartesian product of complete graphs. Each of the constructed paths is of length at most 2 plus the minimum …

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Synthesis Of A Uniformly Spaced Array With Symmetric Amplitude Excitation By A Weighted Least-Square Method, J.A. Jervase, I.H. Zabalawi Apr 2025

Synthesis Of A Uniformly Spaced Array With Symmetric Amplitude Excitation By A Weighted Least-Square Method, J.A. Jervase, I.H. Zabalawi

Sultan Qaboos University Journal For Science

A new, non-iterative technique for synthesizing equispaced linear arrays with symmetric excitation is proposed. The methods is on the computation of an eigenvector of an appropriate real, Symmetric and positive-definite matrix. This technique can be used to determine, given a n complete description of the desired radiation pattern, the array excitation coefficients . These derived excitation will produce, either exactly or approximately, the wanted antenna radiation pattern, depending on its complexity and the number of my elements. A number of design examples are presented to illustrate the practicality and the potential of the proposed method.

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Recursive Estimation In Capture-Recapture Methods, Lakhdar Aggoun, Robert J. Elliott Apr 2025

Recursive Estimation In Capture-Recapture Methods, Lakhdar Aggoun, Robert J. Elliott

Sultan Qaboos University Journal For Science

An important problem in statistical ecology is how to determine the size of an animal population. The best known technique is the capture-recapture technique. A random sample of individuals is captured, tagged in some way and released back into the population. After allowing time for the marked and unmarked individuals to mix sufficiently, a second random sample is taken and the marked ones are observed. Using measure change techniques, we estimate recursively conditional distributions of various quantities.

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