### فهرست مطالب

• Volume:8 Issue:4, 2016
• تاریخ انتشار: 1395/09/07
• تعداد عناوین: 10
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• Sh. A. Safari ?sabet?, M. Farmani * Pages 331-337
Let $R$ be an associative ring with identity. An element $x \in R$ is called $\mathbb{Z}G$-regular (resp. strongly $\mathbb{Z}G$-regular) if there exist $g \in G$, $n \in \mathbb{Z}$ and $r \in R$ such that $x^{ng}=x^{ng}rx^{ng}$ (resp. $x^{ng}=x^{(n)g}$). A ring $R$ is called $\mathbb{Z}G$-regular (resp. strongly $\mathbb{Z}G$-regular) if every element of $R$ is $\mathbb{Z}G$-regular (resp. strongly $\mathbb{Z}G$-regular). In this paper, we characterize $\mathbb{Z}G$-regular (resp. strongly $\mathbb{Z}G$-regular) rings. Furthermore, this paper includes a brief discussion of $\mathbb{Z}G$-regularity in group ýrings.ý
Keywords: Group ring, $pi$, Regular, $mathbb{Z}G$, Regular, Strongly $mathbb{Z}G$, ?regular
• H. ?rouhparvar? * Pages 339-346
This paper presents a class of theoretical and iterative method for linear partial differential equations. An algorithm and analytical solution with a initial condition is obtained using the reduced differential transform method. In this technique, the solution is calculated in the form of a series with easily computable components. There test modeling problems from mathematical mechanic, physic, electronic and so on, and are discussed to illustrate the effectiveness and the performance of the our ýmethod.
Keywords: Reduced differential transform ?method, ? Taylor series, Parabolic equations, Hyperbolic ?equations
• M. Abd El, Aziz* Pages 347-363
The effect of partial slip and temperature dependent fluid properties on the MHD mixed convection flow from a heated, non-linearly stretching surface in the presence of radiation and non-uniform internal heat generation/absorption is investigated. The velocity of the stretching surface was assumed to vary according to power-law form. Thermal transport is analyzed for two types of non-isothermal boundary conditions, variable wall temperature (VWT) and variable surface heat flux (VHF) of the power-law form. The analysis accounts for both temperature dependent viscosity and temperature dependent thermal conductivity. The governing differential equations are transformed by introducing proper non-similarity variables and are solved numerically. The physical significance of the slip parameter, magnetic parameter, radiation parameter, viscosity-temperature parameter, thermal conductivity parameter and buoyancy force parameter on the flow and the thermal fields are shown through graphs and discussed in detail. The values of wall shear stress and the local Nusselt number are tabulated.
Keywords: Slip flow, Mixed convection, Heat source, Stretching surface, Magnetic field, ýRadiation
• F. Abbasi *Ý, T. Allahviranloo, S. Abbasbandy Pages 365-375
Ranking fuzzy numbers is generalization of the concepts of order, and class, and so have fundamental applications. Moreover, deriving the final efficiency and powerful ranking are helpful to decision makers when solving fuzzy problems. Selecting a good ranking method can apply to choosing a desired criterion in a fuzzy environment. There are numerous methods proposed for the ranking of fuzzy numbers, some of them seem to be good in a particular context but not in general. In this paper, a new attitude coupled with the basic thinking of ordering for ranking of fuzzy numbers is proposed. The properties of the proposed method are discussed in detail. The ranking results show that the proposed method can overcome certain shortcomings that exist in the previous ranking methods.The method also has very easy and simple calculations compared to other methods. Finally, numerical examples are presented to illustrate the advantage of our proposed method, and compare them with other common ranking methods. The future prospect of this paper is a new attitude to fuzzy distance, which will be referred to in the ýend.
Keywords: Ranking fuzzy numbers, Transmission average (TA), Fuzzy par, Ambiguity rank, Fuzzy partial ýorder
• Sunilkumar M. ?hosamani? * Pages 377-384
Motivated by the terminal Wiener indexý, ýwe define the Ashwini index $\mathcal{A}$ of trees asý \begin{eqnarray*}ý % ý\nonumber to remove numbering (before each equation)ý
ý\mathcal{A}(T) &=& \sum\limits_{1\leq i
Keywords: Wiener index, terminal Wiener index?, ?Ashwini ?index
• S. M. Hosseini? * Pages 385-394
Considering the contemporary business settings, managers role is more than essential to the viability and further development of an organization. Managers should possess such skills in order to effectively cope with the competition. Multiple attributes decision making (MADM) is an approach employed to solve problems involving selection from among a finite number of alternatives. The aim of this study is to develop a methodology to evaluate managers based on integrating fuzzy AHP and fuzzy TOPSIS approaches. In this paper, I have taken into consideration some important criteria which affect the process of managers selection. I have calculated the weights for each criterion based on Interval-valued fuzzy AHP and then inputted these weights to the fuzzy TOPSIS method to rank managers. The entire methodology is illustrated with the help of a numerical example and finally the rank of each managers is determined according to its results. The proposed method enables decision analysts to better understand the complete evaluation process and provide a more accurate, effective, and systematic decision support tool. Also, the proposed method provides a useful way for handling fuzzy TOPSIS based on fuzzy ýnumbers.ýý
Keywords: Fuzzy number, Fuzzy TOPSIS, Multiple criteria decision, ?making
• L. Gerami ?moazam * Pages 395-400
Firstly, in this paper, we apply the Fuzzy Restricted Variation Method to achieve an analytical and approximate unsymmetrical fuzzy solution for Fully Fuzzy Quadratic Equation. In this application, after finding the real root of 1-cut of $\tilde{A}\tilde{X}^{2}\tilde{B}\tilde{X}\tilde{C}=\tilde{D}$, initial guess is always chosen with possible unknown parameters that leads to highly accurate solution. This technique is applying to solve mentioned equation in four cases via the sign of coefficients and variable that there is not zero in support of them and we solve the problems to find positive or negative solution. This method has been shown to solve effectively, easily and accurately a large class of nonlinear quadratic equations with approximations converging rapidly to accurate solution. In this paper we present the solutions in four cases with formulas, that can be used to write the algorithm for this technique. Finally to illustrate easy application and rich behavior of this method, several examples are ýgiven.ý
Keywords: Fuzzy number, Fully fuzzy quadratic equation, Fuzzy parametric form, Restricted variations, Unsymmetrical fuzzy ?solution
• J. K. Singh*ÝÝ, S. Ghousia ÝbegumÝ, N. JoshiÝÝ Pages 401-414
Effects of Hall current, ion-slip and Coriolis force on unsteady MHD Couette-Hartmann flow of a viscous incompressible electrically conducting fluid through a porous medium bounded by porous plates in the presence of a uniform transverse magnetic field which is either fixed relative to the fluid or to the moving porous plate is investigated using Laplace transform technique. The expressions for the fluid velocity and shear stress at the moving porous plate are also derived. In order to analyze the physical significance and characteristic features of the problem, the graphs for velocity distribution and shear stress distribution at the moving porous plate are generated for different values of non-dimensional parameters. It is observed that the fluid velocity when magnetic field is fixed relative to the moving porous plate is always more than the fluid velocity when magnetic field is fixed relative to the fluid while the shear stress at the moving porous plate when magnetic field is fixed relative to the moving porous plate is always less than the shear stress at the moving porous plate when magnetic field is fixed relative to the ýfluid.
Keywords: Magnetic field, Hall current, Ion, slip, Coriolis force, Permeability, suction, ýinjection
• A. R. Vahidi *, Z. Azimzadeh, M. Shahrestani? Pages 415-421
In this paper a new form of the homptopy perturbation method is used for solving oscillator differential equation, which yields the Maclaurin series of the exact solution. Nonlinear vibration problems and differential equation oscillations have crucial importance in all areas of science and engineering. These equations equip a significant mathematical model for dynamical systems. The accuracy of the Solution equation is very important because the analysis component of the system like vibration amplitude control, synchronization dynamics are dependent to the exact solution of oscillation ýequation.
Keywords: Homotopy perturbation method (HPM)?, ? Differential equations, Non, linear oscillator's equation, Laplace ?transformation
• M. FallahpourÝÝ, M. KhodabinÝ*, K. MaleknejadÝ Pages 423-430
In this paper, a numerical efficient method based on two-dimensional block-pulse functions (BPFs) is proposed to approximate a solution of the two-dimensional linear stochastic Volterra-Fredholm integral equation. Finally the accuracy of this method will be shown by an example.
Keywords: Block, pulse function, Two, dimensional equation, Stochastic integral equation, Volterra, fredholm integral, Operational matrix, Brownian motion process, Ito ýintegral