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Articles 191701 - 191730 of 5153855

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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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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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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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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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Constant Information Design For Binary Response Data, K.A. Abdelbasit Apr 2025

Constant Information Design For Binary Response Data, K.A. Abdelbasit

Sultan Qaboos University Journal For Science

A major problem is designing experiments when the assumed model is nonlinear, is the dependence of the designs on the values of the unknown parameters we consider in this article designs for binary data and generalize the constant information criterion suggested by Fisher (1922). The criterion calls for designs that achieve a specific proportion of the total constant information. This leads to designs where dependence of Fisher’s information on the unknown parameters is very little, thus leading to constant variances. We show that such designs exist for any single parameter model, extending Fisher‘s result for the exponential model. We discuss …

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Calibration Of Transit Operations Planning (Top) Model And Evaluation Of Bus Transit Route Performance In Riyadh, P.A. Koushki, G.A. Ali, Y.A. Al-Nuaim Apr 2025

Calibration Of Transit Operations Planning (Top) Model And Evaluation Of Bus Transit Route Performance In Riyadh, P.A. Koushki, G.A. Ali, Y.A. Al-Nuaim

Sultan Qaboos University Journal For Science

Public transit systems provide mobility for a large percentage of urban residents very cost-effectively and with minimum negative impact on the environment. ln spite of their vital and indispensable services; however , The majority of transit systems worldwide suffer from financial neglect and are forced to rely heavily on government subsidies for survival. In response to the rapidly shrinking funds and subsidy levels transit managements have to focus attention on ways to improve service operations. The management of public transit systems in Saudi Arabia is no exception to this trend. This study is aimed at evaluating the service performance of …

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Nodulation Of Medicago Sativa L. By Different Rhizobium Strains In The Sultanate Of Oman, A.E. Elshafie, R. Victor, N. Al-Mugbali Apr 2025

Nodulation Of Medicago Sativa L. By Different Rhizobium Strains In The Sultanate Of Oman, A.E. Elshafie, R. Victor, N. Al-Mugbali

Sultan Qaboos University Journal For Science

Three native Rhizobium strains were isolated from Musandam. Buraimi and the Agricultural Experiment Station at Sultan Qaboos University in the Sultanate of Oman. An internationally known Rhizobium strain (TAI. 1373} was obtained from the Nitrogen Fixation for Tropical Agriculture I.egume Collection at the University of Hawaii. U.S.A-. for comparison. The different abilities of the strains to nodulate Medicago sativa I. were investigated. Different plant parameters namely, the fresh and dry weights of the shoot (g/plant ). the number of nodules per plant and the nitrogenase activity (u mole C2H2/sample/3hours) were measured. The results showed that the native Rhizobia were capable …

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Towards Solutions Of Seepage Problems, A.A. Al-Rawas, M.Y. Al-Aghbari, N. Sivakugan, J.A. Al-Shihi Apr 2025

Towards Solutions Of Seepage Problems, A.A. Al-Rawas, M.Y. Al-Aghbari, N. Sivakugan, J.A. Al-Shihi

Sultan Qaboos University Journal For Science

Flow rates are traditionally used for solving seepage problems in soils. In this paper, the method of fragments is presented as a good alternative for solving seepage problems. A user friendly and interactive computer program for the method of fragments has been developed. Several randomly selected problems are solved by the flow net method, the method of fragments and the finite difference method. It was found that the method of fragments and the finite difference method gave very close predictions of the quantity of flow, exit gradient and uplift force. Furthermore, the effects of different positions and lengths, and number …

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Model-Tracing Based Approach To Intelligent Program Diagnosis, Haider Ali Ramadhan Apr 2025

Model-Tracing Based Approach To Intelligent Program Diagnosis, Haider Ali Ramadhan

Sultan Qaboos University Journal For Science

Model-tracing based approach to intelligent program diagnosis and tutoring emphasizes the fact that the student’s design decisions are traced as the students develops the program Systems based on this model monitor the user's actions as the moves along the solution path, automatically analyzes partial solutions for semantic errors and misconceptions, and offers guidance whenever he deviates from the correct solution path. In this way, the system always checks to see if the student is following a design path of an idea model. Buggy paths are pruned as soon as they are discovered. Through this approach to automatic diagnosis and tutoring …

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Igbt Based Dc/Dc Converter, M. Akherraz Apr 2025

Igbt Based Dc/Dc Converter, M. Akherraz

Sultan Qaboos University Journal For Science

This paper presents an in-depth analytical and experimental investigation of an indirect DC-DC converter. The DC-AC conversion is a full bridge based on IGBT power modules, and the AC-DC conversion is done via a high frequency AC link and a first diode bridge. The AC link, which consists of snubbing capacitors and a variable air-gap transformer, is analytically designed to fulfill Zero Voltage commutation requirement. The proposed converter is simulated using PSPICE and a prototype is designed built and tested in the laboratory. PSPICE simulation and experimental results are presented and compared.

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Fourth-Order Approximation Of The Fundamental Matrix Of Linear System Of Differential Equations, A.M. Hussein Apr 2025

Fourth-Order Approximation Of The Fundamental Matrix Of Linear System Of Differential Equations, A.M. Hussein

Sultan Qaboos University Journal For Science

A fourth-order approximation to the fundamental matrix of a system of linear differential equations is presented in closed form as a matrix exponential. The matrix exponential is then discretized over the interval of integration l‘adc approximation together with the method of scaling and squaning (Moler et at 1978) is used to evaluate the matrix exponential. This approach is suitable for solving both initial and boundary value problems with mixed boundary conditions. The approximating matrix can also be used as an integrating operator for methods which require information about the solution along the discretized subintervals. An example of a boundary value …

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Distributed Simulation Of Open Cyclic Queuing Networks, Saad Harous Apr 2025

Distributed Simulation Of Open Cyclic Queuing Networks, Saad Harous

Sultan Qaboos University Journal For Science

In this paper we present the results of an experimental performance study of distributed simulation of open cyclic queuing networks using a minor variation of the deadlock detection and recovery based algorithm of Chandy and Misra. One major part of this study is to determine the effect of overhead on distributed simulation. Moreover, we measure certain refined notions of ideal speedup ratio." These ratios are more refined than just the number of processors in the sense that they capture the potentially achievable speedups of distributed simulation more closely.

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On The Roles Of Interatomic Interactions And Coordination Numbers On Einstein Temperatures Of 3d Transition Metals, M.A. Khaleque, G.M. Bhuiyan, Ri.M.A Rashid, S.M.M Rahman Apr 2025

On The Roles Of Interatomic Interactions And Coordination Numbers On Einstein Temperatures Of 3d Transition Metals, M.A. Khaleque, G.M. Bhuiyan, Ri.M.A Rashid, S.M.M Rahman

Sultan Qaboos University Journal For Science

We have investigated the roles of the coordination numbers and interatomic interactions on Einstien temperatures 0e for a number of bee 3d transition metals. We have employed a few of the popular transition metal pseudopotentials in the Calculations aiming at a comparative survey of the roles of these pseudopotentials on the Einstein temperature; the role of the neighboring atoms on the latter emerges as a by-product of the calculations.

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Recurrence Relations For The Equilibrium Means Of Distributions Arising In Chemical Reactions, E.K. Elsheikh Apr 2025

Recurrence Relations For The Equilibrium Means Of Distributions Arising In Chemical Reactions, E.K. Elsheikh

Sultan Qaboos University Journal For Science

In this paper we derive recurrence relations that describe how the equilibrium mean of the number molecules of a reactant varies with each of the parameters defining the initial state for four basic reversible chemical reactions. In essence, the relations provide a rationale for updating the equilibrium mean following the addition (or removal) of a molecule of one of the types involved in the reaction, there being a relation for each type. With a new parameterization introduced for each reaction, the relations provide a convenient means of evaluating the means, variances and other important moments without any need to work …

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Using Switching Linear Systems To Reach A Prespecified Traget, A. Benmerzouga Apr 2025

Using Switching Linear Systems To Reach A Prespecified Traget, A. Benmerzouga

Sultan Qaboos University Journal For Science

A conventional enumeration approach, and a new approach for the solution of the control of switched linear systems with input constraints are presented. The main objective in this work is to determine control sequences {U‘(K), i -l , M and k –O, l, ….., N - l} which transfer the system from a given initial state X(0) to a specific target state Xt, (or to be as close as possible). Considering both the conventional enumeration and the new approach, extensive computer simulations are performed using the discrete time system obtained by sampling (or discretizing) a continuous system. The new approach …

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