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Showing 96 results for Type of Study: Research Article

Fatemeh Sadat Seyed Esmaeili, Mohsen Rostamy-Malkhalifeh, Farhad Hosseinzadeh Lotfi,
Volume 1, Issue 2 (12-2020)
Abstract

The main goal of this paper is to propose interval network data envelopment analysis (INDEA) model for performance evaluation of network decision making units (DMUs) with two-stage network structure under data uncertainty. It should be explained that for dealing with uncertainty of data, an interval programming method as a popular uncertainty programming approach is applied. Also, to show the applicability of proposed model, INDEA approach is implemented for performance measurement and ranking of 10 insurance companies from Iranian insurance industry. Note that insurance companies are undoubtedly one of the most important pillars of the financial markets, whose great performance will drive the economy of the country. The empirical results indicate that the proposed INDEA is capable to be utilized to assess the performance of two-stage DMUs in the presence of interval data.
Esa Sharahi, Esmaiel Peyghan, Amir Baghban,
Volume 1, Issue 2 (12-2020)
Abstract

Our aim in this paper, is applying Adams-Moulton algorithm to find the geodesics as the answers of the classical system of ordinary differential equations on a 2-dimensional surface for which a Riemannian metric is defined.
Abbas Zivari-Kazempour, Mohammad Reza Hadadi,
Volume 1, Issue 2 (12-2020)
Abstract

In this paper, some basic results under various conditions for $varphi$-convex functions are investigated.

 
Silvestru Sever Dragomir,
Volume 2, Issue 1 (6-2021)
Abstract

In this paper we obtain some new multiplicative inequalities for Heinz operator mean.
Mikail Resat Mikail, Elman Hazar, Ali Farajzadeh, Erhan Erdel, Fariz Mikailsoy,
Volume 2, Issue 1 (6-2021)
Abstract

The objective of this work is to investigate the infl uence of boundary conditions at depth soil on the development of methods to determine the soil′s apparent thermal diffusivity based on solution of inverse problems of a heat-transfer equation. Experimental investigations were carried out to establish the influence of boundary conditions at depth in soil on the solution of inverse problems of modeling of heat transfer in soils. For this purpose, 1 soil profile in the land at different depths (x=0, 5, 10, 15,  20, 40, 60 cm) thermal sensors (Temperature recorder Elitech RC-4) have been installed to measure soil temperatures depending on time and depths. Based on these data, the apparent  thermal diffusivity in soils was calculated using the classical (layered) and proposed (point) methods developed for the case with one and two harmonics, and they were compared and the calculated characteristics were compared with the experimental results. It was found that the proposed point methods best reflect the movement of heat in the soil profile. 
Morteza Sohrabi,
Volume 2, Issue 1 (6-2021)
Abstract

Let $widetilde{{C}_{varphi}}$ be the Aluthge transform of composition operator on $L^{2}(Sigma)$. The main result of this paper is characterizations of Aluthge transform of composition operators in some operator classes that are weaker than hyponormal, such as hyponormal, quasihyponormal, paranormal, $*$-paranormal on $L^{2}(Sigma)$. Moreover, to explain the results, we provide several useful related examples to show that $widetilde{{C}_{varphi}}$ lie between these classes.
Najmeh Ghaderi, Mohammad Hadi Farahi,
Volume 2, Issue 1 (6-2021)
Abstract

‎A numerical approach based on Bernstein polynomials is presented to unravel optimal control of nonlinear systems. The operational matrices of differentiation, integration and product are introduced. Then, these matrices are implemented to decrease the solution of nonlinear optimal control problem to the solution of the quadratic programming problem which can be solved with many algorithms and softwares. This method is easy to implement it with an accurate solution. Some examples are included to demonstrate the validity and applicability of the technique.

Ganesa C Moorthy, Gurusamy Siva,
Volume 2, Issue 1 (6-2021)
Abstract

The definition of bipolar multiplicative metric space is introduced in this article, and in this space some properties are derived. Multiplicative contractions for covariant and contravariant maps are defined and fixed points are obtained. Also, some fixed point results of covariant and contravariant maps satisfying multiplicative contraction conditions are proved for bipolar multiplicative metric spaces. Moreover, Banach contraction principle and Kannan fixed point theorem are generalized.
Seyyed Mohammad Tabatabaie, Alireza Bagheri Salec,
Volume 2, Issue 1 (6-2021)
Abstract

In this paper we prove the Riesz-Thorian interpolation theo-rem for weighted Orlicz and weighted Morrey Spaces.
Kobra Oustad,
Volume 2, Issue 1 (6-2021)
Abstract

‎In this paper‎, ‎we study character amenability of semigroup algebras `ell^{1}(S)` and weighted semigroup algebras $ ell^{1} (S,omega)$‎, ‎for a certain semigroups such as right(left) zero semigroup‎, ‎rectangular band semigroup‎, ‎band semigroup and uniformly locally finite inverse semigroup‎. ‎In particular‎, ‎we show that for a right (left) zero semigroup or a rectangular band semigroup‎, ‎character amenability‎, ‎amenability‎, ‎pseudo‎ - ‎amenability of $ ell^{1} (S,omega)$‎, ‎for each weight $ omega $‎, ‎are equivalent‎. ‎We also show that for an archimedean semigroup $ S $‎, ‎character pseudo‎ - ‎amenability‎, ‎amenability‎, ‎approximate amenability and pseudo-amenable of $ ell^{1}(S) $ are equivalent‎.


Moosa Gabeleh, Jack Markin,
Volume 2, Issue 1 (6-2021)
Abstract

The aim of this note is to show that the main conclusion of a recent paper by Sadiq Basha [S. Sadiq Basha, Global optimization in metric spaces with partial orders, emph{Optimization, 63 (2014), 817-825}] can be obtained as a consequence of corresponding existing results in fixed point theory in the setting of partially ordered metric spaces. Moreover, by a similar approach, we prove that in the paper [V. Pragadeeswarar, M. Marudai, Best proximity points: approximation and optimization in partially ordered metric spaces, emph{Optim. Lett. 7 (2013), 1883–1892}] the results are not real generalizations but particular cases of existing fixed point theorems in the literature.
Mehdi Rahimi, Ahmad Shakouri, Mohammad Mohammadi,
Volume 2, Issue 1 (6-2021)
Abstract

In this paper, we review some properties of the entropy of random dynamical systems. We define
a local entropy map for random dynamical systems and study some of its properties. We extract the
entropy of random dynamical systems from the introduced map.
Morteza Koozehgar Kalleji,
Volume 2, Issue 1 (6-2021)
Abstract

S. G. Mikhlin proved the boundedness of the Fourier multiplier operator in the classical Lebesgue space if the multiplier function is a bounded function. In cite{MWW}, the authors obtained the same result of the classical Morrey space. In this paper, we prove that Mikhlin operator with bounded multiplier function is bounded operator on Morrey space with variable exponent which is containing the classical Lebesgue space with variable exponent and the classical Morrey space.
‎zahra‎‎ ‎ Sarvari, Mojtaba Ranjbar, Shahram Rezapour,
Volume 2, Issue 1 (6-2021)
Abstract

In this paper‎, ‎the polynomial differential quadrature method (PDQM) is implemented to find the numerical solution of the generalized Black-Scholes partial differential equation‎. ‎The PDQM reduces the problem into a system of first order non-linear differential equations and then‎, ‎the obtained system is solved by optimal four-stage‎, ‎order three strong stability-preserving time-stepping Runge-Kutta (SSP-RK43) scheme‎. ‎Numerical examples are given to illustrate the efficiency of the proposed method‎.


Mohammed Danish Siddiqi, Ghodratallah Fasihi-Ramandi, Mohammed Hasan,
Volume 2, Issue 1 (6-2021)
Abstract

‎The present research paper is concerned about a couple of optimal inequalities for the Casorati curvature of submanifolds in an $({varepsilon})$-almost para-contact manifolds precisely $(varepsilon)$-Kenmotsu manifolds endowed with semi-symmetric metric connection (briefly says $SSM$) by adopting the T‎. ‎Opreachr('39')s optimization technique.‎


Gurusamy Siva,
Volume 2, Issue 2 (12-2021)
Abstract

Common fixed point theorems for three self mappings satisfying generalized contractive conditions in cone metric spaces are derived. Also, some common fixed point results for two self mappings are deduced. Moreover, these all results generalize some important familiar results. Given example to illustrate our main result. Furthermore, an existence theorem for the common solution of the two Urysohn integral equations obtained by using our main result.
Behrooz Olfatian Gillan, Amir Sahami,
Volume 2, Issue 2 (12-2021)
Abstract

‎In this note‎, ‎we show that cite[Theorem 2.3]{ghorb} is not true‎. ‎In fact‎, ‎we show that $ell^{1}(mathbb{N}_{max})$ is a unital Banach algebra which is $phi$-pseudo amenable but it is not $phi$-approximate biflat for some $phiin Hom(ell^{1}(mathbb{N}_{max}))$‎.


Esmaeil Mombini1, Mohsen Rostamy-Malkhalifeh2, Mansor Saraj,
Volume 2, Issue 2 (12-2021)
Abstract

In economics, a production function relates the outputs of a production process to the inputs of the production. Generally, the production function is not available due to the complexity of the production process, the changes in production technology. Therefore, we have to consider an approximation of the production function. Data Envelopment Analysis (DEA) is a non-parametric methodology for obtaining an approximation of the production function and assessing the relative efficiency of economic units. Sensitivity analysis and sustainability evaluation of Decision Making Units (DMUs) are as the most important concerns of Decision Makers (DM). This study considers the sustainability radius of economic performance of DMUs and then proposes some approaches combined with sensitivity analysis for determining the sustainability radius of cost efficiency, revenue efficiency and profit efficiency of units. The proposed approaches eliminate the unit under evaluation from the observed data and disturb the data of it, based on the sensitivity analysis, to determine the sustainability radius of cost efficiency, revenue efficiency and profit efficiency of decision making units. Potential application of our proposed methods is illustrated with a dataset consisting of 21 medical centers in Taiwan.
Tohid Kasbi, Vahid Roomi,
Volume 2, Issue 2 (12-2021)
Abstract

‎The existence and number of limit cycles is an important problem ‎in the study of ordinary differential equations and dynamical‎

‎systems‎. ‎In this work we consider $2$-dimensional predator-prey‎ ‎system and‎, ‎using Poincarchr('39'){e}-Bendixson theorem and LaSallechr('39')s‎ ‎invariance principle‎, ‎present some new necessary and some new‎ ‎sufficient conditions for the existence and nonexistence of limit‎

‎cycles of the system‎. ‎These results extend and improve the‎ ‎previous results in this subject‎. ‎Local or global stability of the‎

‎rest points of a system is also an important issue in the study of‎ ‎the equations and systems‎. ‎In this paper a sufficient condition‎

‎about global stability of a critical point of the system will also‎ ‎be presented‎. ‎Our results are sharp and are applicable for‎

‎predator-prey systems with functional response which is function‎ ‎of prey and predator‎. ‎At the end of the manuscript‎, ‎some examples‎

‎of well-known predator-prey systems are provided to illustrate our‎ ‎results‎.


Akbar Dehghan Nezhad, Sareh Beizavi,
Volume 2, Issue 2 (12-2021)
Abstract

In this paper, the chromatic polynomial structure on Riemannian manifolds and the almost golden structure on the tangent bundle of a Finsler manifold have been studied. A class of g-natural metrics on the tangent bundle of a Finsler manifold have been considered and some conditions under which the golden structure is compatible with the above-mentioned metric are proposed. The Levi-Civita connection associated with the mentioned metric is calculated and the results of it are presented. Finally, the integrability of the golden structure and its compatibility with the covariant derivative is studied.



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