مرور Volume 18, Issue 4 بر اساس عنوان

  • Complete Convergence and Some Maximal Inequalities for Weighted Sums of Random Variables 

    Amini, M. (University of Tehran, 2007-12-01)
    Let  be a sequence of arbitrary random variables with  and , for every  and  be an array of real numbers. We will obtain two maximal inequalities for partial sums and weighted sums of random variables and also, we will ...

  • A Computational Meshless Method for Solving Multivariable Integral Equations 

    Babolian, E. (University of Tehran, 2007-12-01)
    In this paper we use radial basis functions to solve multivariable integral equations. We use collocation method for implementation. Numerical experiments show the accuracy of the method.

  • Derivations on Certain Semigroup Algebras 

    Lashkarizadeh Bami, M. (University of Tehran, 2007-12-01)
    In the present paper we give a partially negative answer to a conjecture of Ghahramani, Runde and Willis. We also discuss the derivation problem for both foundation semigroup algebras and Clifford semigroup algebras. In ...

  • Essentially Retractable Modules 

    Vedadi, M.R. (University of Tehran, 2007-12-01)
    We call a module  essentially retractable if HomR for all essential submodules N of M. For a right FBN ring R, it is shown that: (i)  A non-zero module  is retractable ...

  • Modified Progressive Type-II Censoring Procedure in Life-Testing under the Weibull Model 

    Khodadadi, M. (University of Tehran, 2007-12-01)
    In this paper we introduce a new scheme of censoring and study it under the Weibull distribution. This scheme is a mixture of progressive Type II censoring and self relocating design which was first introduced by Srivastava ...

  • Nonlinear Two-Phase Stefan Problem 

    Ivaz, K. (University of Tehran, 2007-12-01)
    In this paper we consider a nonlinear two-phase Stefan problem in one-dimensional space. The problem is mapped into a nonlinear Volterra integral equation for the free boundary.

  • On the U-WPF Acts over Monoids 

    Golchin, A. (University of Tehran, 2007-12-01)
    Valdis Laan in [5] introduced an extension of strong flatness which is called weak pullback flatness. In this paper we introduce a new property of acts over monoids, called U-WPF which is an extension of weak ...

  • Synthesis of Binary Ti-Si Mixed Oxides Nanoparticles with Rutile Structure as Selective Catalyst for Epoxidation of Alkenes 

    Farzaneh, F. (University of Tehran, 2007-12-01)
    The nanoparticles of Ti-Si mixed oxides (NTSO) with Rutile structure were prepared by sol-gel method in a mixture of alcohol and water as solvent. The solid product was characterized by XRD, FTIR, SEM, TEM, UV, TGA and ...