Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
Combined effect of suspended particles and rotation on thermosolutal convection in a viscoelastic fluid saturating a Darcy-Brinkman porous medium
319
325
EN
G. C.
Rana
Department of Mathematics, NSCBM Govt. P. G. College, Hamirpur-177 005, Himachal Pradesh
R. C.
Thakur
Department of Mathematics, Govt. P. G. College, Dhaliara, Kangra-177 103, Himachal Pradesh, India
10.22099/ijsts.2013.1630
In this paper, the combined effect of suspended (fine dust) particles and rotation on the onset of thermosolutal convection in an elastico-viscous fluid in a porous medium is studied. For the porous medium, the Brinkman model is employed and Rivlin-Ericksen model is used to characterize viscoelastic fluid. By applying normal mode analysis method, the dispersion relation has been derived and solved analytically. It is observed that the rotation, stable solute gradient, suspended particles, gravity field and viscoelasticity introduce oscillatory modes. For stationary convection, it is observed that the rotation, stable solute gradient have a stabilizing effect and suspended particles have a destabilizing effect on the system whereas Darcy number and medium permeability have stabilizing/destabilizing effects under certain conditions. The effects of rotation, stable solute gradient, suspended particles, Darcy number and medium permeability have also been shown graphically.
Brinkman porous medium,Rivlin-Ericksen fluid,rotation,suspended particles,thermosolutal convection,viscosity,viscoelasticity
http://ijsts.shirazu.ac.ir/article_1630.html
http://ijsts.shirazu.ac.ir/article_1630_6ad4ef4ca441fd758f0ca9b39f9312d5.pdf
Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
Approximation of stochastic advection-diffusion equation
using compact finite difference technique
327
333
EN
M.
Bishehniasar
Department of Mathematics, University of Sistan and Baluchestan Zahedan, Iran
A. R.
Soheili
The Center of Excellence on Modeling and Control Systems,
Department of applied Mathematics, School of Mathematical science,
Ferdowsi University of Mashhad, Mashhad
10.22099/ijsts.2013.1631
In this paper, we propose a new method for solving the stochastic advection-diffusion equation of Ito type. In this work, we use a compact finite difference approximation for discretizing spatial derivatives of the mentioned equation and semi-implicit Milstein scheme for the resulting linear stochastic system of differential equation. The main purpose of this paper is the stability investigation of the applied method. Finally, some numerical examples are provided to show the accuracy and efficiency of the proposed technique.
Stochastic partial differential equation,compact finite difference scheme,Stability,semi-implicit Milstein method
http://ijsts.shirazu.ac.ir/article_1631.html
http://ijsts.shirazu.ac.ir/article_1631_22e92753f3dad7596b3b82cbc3100358.pdf
Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
Bayesian and non-bayesian estimation of stress–strength
model for Pareto type I distribution
335
342
EN
A. I.
Shawky
Department of Statistics, Faculty of Sciences, King Abdulaziz University,
P.O. Box 80203, Jeddah 21589
F. H.
Al-Gashgari
Department of Statistics, Faculty of Sciences for Girls, King Abdulaziz University,
P.O. Box 53873, Jeddah 21593, Saudi Arabia
10.22099/ijsts.2013.1632
This article examines statistical inference for where and are independent but not identically distributed Pareto of the first kind (Pareto (I)) random variables with same scale parameter but different shape parameters. The Maximum likelihood, uniformly minimum variance unbiased and Bayes estimators with Gamma prior are used for this purpose. Simulation studies which compare the estimators are presented. Moreover, sensitivity of Bayes estimator to the prior parameters is considered.
Bayesian estimator,Maximum likelihood estimator (MLE),Pareto of first kind,uniformly minimum variance unbiased estimator (UMVUE),stress-strength model
http://ijsts.shirazu.ac.ir/article_1632.html
http://ijsts.shirazu.ac.ir/article_1632_bc2d251569304a0afdc39c565a46af4b.pdf
Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
On BC-generalized Landsberg Finsler metrics
343
347
EN
M.
Zamanzadeh
Bijar Branch, Islamic Azad University Bijar
B.
Najafi
Department of Mathematics, Faculty of Science, Shahed University of Tehran, Tehran, Iran
10.22099/ijsts.2013.1633
Equality of -curvatures of the Berwald and Cartan connections leads to a new class of Finsler metrics, so-called BC-generalized Landsberg metrics. Here, we prove that every BC-generalized Landsberg metric of scalar flag curvature with dimension greater than two is of constant flag curvature.
Finsler structure,Landsberg metric,generalized Landsberg metric,scalar flag curvature
http://ijsts.shirazu.ac.ir/article_1633.html
http://ijsts.shirazu.ac.ir/article_1633_c8dcd51ee11af2c9a5cef5d64ae37a05.pdf
Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
A preemptive restarting approach to beating the
inherent instability of Lanczos-type algorithms
349
358
EN
M.
Farooq
Department of Mathematics, University of Peshawar, 25120, Khyber Pakhtunkhwa
A.
Salhi
Department of Mathematical Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
10.22099/ijsts.2013.1634
Lanczos-type algorithms are well known for their inherent instability. They typically breakdown occurs when relevant orthogonal polynomials do not exist. Current approaches to curing breakdown rely on jumping over the non-existent polynomials to resume computation. This may have to be used many times during the solution process. We suggest an alternative to jumping, which consists of restarting the algorithms that fail. Three different strategies can be taken: (ST1) Restarting following breakdown of the algorithm in use; (ST2) pre-emptive restarting after a fixed number of iterations; (ST3) restarting when near breakdown is detected through monitoring. We describe a restarting framework with a generic algorithm that invokes one or the other of the three strategies suggested. Four of the most prominent recently developed Lanczos-type algorithms namely, and will be presented and then deployed in the restarting framework. However, we will only report on results obtained with strategy ST2 as it is the only viable one at the moment.
Lanczos algorithm,Systems of Linear Equations,Formal Orthogonal Polynomials, Restarting, Switching, Breakdown
http://ijsts.shirazu.ac.ir/article_1634.html
http://ijsts.shirazu.ac.ir/article_1634_6f943b0d0733d9fee2c5c1cae69b892c.pdf
Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
Symplectic Hodge theory, harmonicity, and Thom duality
359
363
EN
M.
Bahramgiri
Graduate School of Management and Economics Sharif University of Technology
10.22099/ijsts.2013.1635
We study the notion of harmonicity in the sense of symplectic geometry, and investigate the geometric properties of harmonic Thom forms and distributional Thom currents, dual to different types of submanifolds. We show that the harmonic Thom form associated to a symplectic submanifold is nowhere vanishing. We also construct symplectic smoothing operators which preserve the harmonicity of distributional currents and using these operators, construct harmonic Thom forms for co-isotropic submanifolds, which unlike the harmonic forms associated with symplectic submanifolds, are supported in an arbitrary tubular neighborhood of the manifold.
Harmonicity,duality,Thom class,Hodge theory,symplectic,distributional currents,smoothing operators,oriented submanifold
http://ijsts.shirazu.ac.ir/article_1635.html
http://ijsts.shirazu.ac.ir/article_1635_1a20b2d7b1e35b156f03b7bb2f5ad63e.pdf
Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
Some kinds of -fuzzy ideals of ternary semigroups
365
378
EN
N.
Rehman
Department of Basic Sciences, Riphah International University, Islamabad, Pakistan
M.
Shabir
2Department of Mathematics, Quaid-i-Azam University, Islamabad, Pakistan
10.22099/ijsts.2013.1636
Generalizing the concepts of -fuzzy (left, right, lateral) ideals, -fuzzy quasi-ideals and -fuzzy bi (generalized bi-) ideals in ternary semigroups, the notions of -fuzzy (left, right, lateral) ideals, -fuzzy quasi-ideals and -fuzzy bi (generalized bi-) in ternary semigroups are introduced and several related properties are investigated. Some new results are obtained.
Ternary semigroups,-fuzzy ideals,-fuzzy quasi-ideals,-fuzzy ideals bi-ideals
http://ijsts.shirazu.ac.ir/article_1636.html
http://ijsts.shirazu.ac.ir/article_1636_9f7826714c3ad66e4cae9235cc70f2ce.pdf
Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
An optimal control approach for arbitrary order
singularly perturbed boundary value problems
379
388
EN
M.
Zarepour
Department of Mathematics, Yazd University, P.O. Box: 89195-741 Yazd, Iran
G. B.
Loghmani
Department of Mathematics, Yazd University
10.22099/ijsts.2013.1637
The aim of this paper is to introduce a new approach for obtaining the numerical solution of singulary perturbed boundary value problems based on an optimal control technique. In the proposed method, first the mentioned equations are converted to an optimal control problem. Then, control and state variables are approximated by Chebychev series. Therefore, the optimal control problem is reduced to a parametric optimal control problem (POC) subject to algebric constraints. Finally, the obtained POC is solved numerically using an iterative optimization technique. In this method, a new idea is proposed which enables us to apply the new technique for almost all kinds of singularly perturbed boundary value problems. Some numerical examples are solved to highlight the advantages of the proposed technique.
Singularly perturbed boundary value problem,parametric optimal control,Optimal control problem
http://ijsts.shirazu.ac.ir/article_1637.html
http://ijsts.shirazu.ac.ir/article_1637_a9995d56a60e51847fb33cd32294b719.pdf
Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
Boundary layer problem for system of first order of ordinary differential equations with linear non-local boundary conditions
389
396
EN
M.
Jahanshahi
Department of Mathematics, Azarbaijan Shahid Madani University, 5375171379, Tabriz
A. R.
Sarakhsi
Department of Mathematics, Azarbaijan Shahid Madani University, 5375171379, Tabriz, Iran
S.
Asharafi
Department of Mathematics, Azarbaijan Shahid Madani University, 5375171379, Tabriz, Iran
N.
Aliev
Department of Mathematics, Baku State University, Baku, Azerbaijan
10.22099/ijsts.2013.1638
In this paper we study the boundary layer problems in which boundary conditions are non-local. Here we try to find the necessary conditions by the help of fundamental solution to the given adjoint equation. By getting help from these conditions, at first the boundary condition is changed from non-local to local. The main aim of this paper is to identify the location of the boundary layer. In other words, at which point the boundary layer is formed.
Singular perturbation problems,boundary layer,fundamental solution,necessary conditions
http://ijsts.shirazu.ac.ir/article_1638.html
http://ijsts.shirazu.ac.ir/article_1638_138c842f9ce699a3b1ca11ff19b5855a.pdf
Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
On generalized I-statistical convergenceof order
397
402
EN
E.
Savas
Department of Mathematics, Istanbul Commerce University, Uskudar-Istanbul
10.22099/ijsts.2013.1639
The goal of this paper is to generalize the recently introduced summability method and introduce double statistical convergence of order by using ideal. We also investigate certain properties of this convergence.
ideal,filter,I- double statistical convergence of order α,I_λ- double statistical convergence of order α, closed subspace
http://ijsts.shirazu.ac.ir/article_1639.html
http://ijsts.shirazu.ac.ir/article_1639_5c4780979b216e7f063511e6a922a483.pdf
Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
On characterization of spacelike dual biharmonic curves
in dual Lorentzian Heisenberg group
403
410
EN
T.
Korpinar
Department of Mathematics, Mus Alparslan University, 49250, Mus, Turkey
E.
Turhan
Department of Mathematics, Firat University, 23119, Elazig, Turkey
V.
Asil
3Department of Mathematics, Firat University, 23119, Elazig
10.22099/ijsts.2013.1640
In this paper, we study spacelike dual biharmonic curves. We characterize spacelike dual biharmonic curves in terms of their curvature and torsion in the Lorentzian dual Heisenberg group . We give necessary and sufficient conditions for spacelike dual biharmonic curves in the Lorentzian dual Heisenberg group . Therefore, we prove that all spacelike dual biharmonic curves are spacelike dual helix. Moreover, we give their explicit parametrizations of spacelike dual biharmonic curves. Finally, we illustrate our main results in Figs. 1 and 2.
Bienergy,biharmonic curve,Helix,Heisenberg group
http://ijsts.shirazu.ac.ir/article_1640.html
http://ijsts.shirazu.ac.ir/article_1640_c99b982ac35eddb02110b1791a7b0378.pdf
Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
Graded prime spectrum of a graded module
411
420
EN
N. A.
Ozkiırisci
Department of Mathematics, Faculty of Arts and Science, Yildiz
Technical University, 34210, Esenler, Istanbul
K. H.
Oral
Department of Mathematics, Faculty of Arts and Science, Yildiz
Technical University, 34210, Esenler, Istanbul, Turkey
U.
Tekir
Department of Mathematics, Faculty of Arts and Science, Marmara University, 34722, Goztepe, Istanbul, Turkey
10.22099/ijsts.2013.1641
Let be a graded ring and be a graded -module. We define a topology on graded prime spectrum of the graded -module which is analogous to that for , and investigate several properties of the topology.
Graded module,graded prime spectrum,graded prime submodule
http://ijsts.shirazu.ac.ir/article_1641.html
http://ijsts.shirazu.ac.ir/article_1641_2c038b0eafc3b894e8058709f74ed513.pdf
Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
The multi-step homotopy analysis method: A powerful
scheme for handling non-linear oscillators
421
429
EN
M.
Zurigat
Department of Mathematics, Al al-Bayt University, Mafraq, Jordan
S.
Al-Shara
Department of Mathematics, Al al-Bayt University, Mafraq, Jordan
S.
Momani
Department of Mathematics, University of Jordan, Amman
A.
Alawneh
Department of Mathematics, University of Jordan, Amman, Jordan
10.22099/ijsts.2013.1642
This paper presents approximate analytical solutions for nonlinear oscillators using the multi-step homotopy analysis method (MSHAM). The proposed scheme is only a simple modification of the homotopy analysis method, in which it is treated as an algorithm in a sequence of small intervals (i.e. time step) for finding accurate approximate solutions to the corresponding problems. Several illustrative examples are given to demonstrate the effectiveness of the present method. Figurative comparisons between the MSHAM and the classical fourth-order Runge-Kutta method (RK4) reveal that this modified method is very effective and convenient.
Non-linear oscillators,homotopy analysis method,numerical solutions
http://ijsts.shirazu.ac.ir/article_1642.html
http://ijsts.shirazu.ac.ir/article_1642_70909ef1ebb1fef861842127d76a1c61.pdf
Shiraz University
Iranian Journal of Science and Technology (Sciences)
1028-6276
37
3.1
2013
09
16
A system of generalized resolvent equations involving
generalized pseudocontractive mapping
431
438
EN
R.
Ahmad
Department of Mathematics, Aligarh Muslim University, Aligarh-202002, India
M.
Akram
Department of Mathematics, Aligarh Muslim University, Aligarh-202002
10.22099/ijsts.2013.1643
Generalized resolvent equations; variational inclusions; algorithm; convergence; generalized pseudocontractive mapping
Generalized resolvent equations,variational inclusions,algorithm,convergence,generalized pseudocontractive mapping
http://ijsts.shirazu.ac.ir/article_1643.html
http://ijsts.shirazu.ac.ir/article_1643_65e5be04ad85dbab8e469418090b76a7.pdf