Kokab Chalambari; Hamideh Ebrahimi; zainab ayati
Volume 13, Issue 1 , Spring 2021
Abstract
In this research, differential quadrature radial basis functions Method is performed to a fractional order model of HIV infection of CD4+T. Here, Caputo fractional derivative is used and it is approximated by forward finite difference method. Results have been compared with the results of Laplace Adomian ...
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In this research, differential quadrature radial basis functions Method is performed to a fractional order model of HIV infection of CD4+T. Here, Caputo fractional derivative is used and it is approximated by forward finite difference method. Results have been compared with the results of Laplace Adomian decomposition method (LADM), Laplace Adomian decomposition method-pade (LADM-pade), Runge-Kutta, Variational iteration method (VIM) and Variational iteration method-pade (VIM-Pade) for α_1=α_2=α_3 and residual functions have been plotted. And also approximate solutions of suggested method for different order of fractional derivatives have been shown.
Fereshteh Saemi; Hamideh Ebrahimi; Mahmoud Shafiee
Volume 13, Issue 1 , Spring 2021
Abstract
The current research approximates the unknown function based on the normalized Müntz−Legendre polynomials (NMLPs) in conjunction with a spectral method for the solution of nonlinear Fredholm and Volterra integral equations. In this method, by using operational matrices, a system of algebraic ...
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The current research approximates the unknown function based on the normalized Müntz−Legendre polynomials (NMLPs) in conjunction with a spectral method for the solution of nonlinear Fredholm and Volterra integral equations. In this method, by using operational matrices, a system of algebraic equations is derived that can be readily handled through the use of the Newton scheme. The stability, error bound, and convergence analysis of the method are discussed in detail by preparing some theorems. Several illustrative examples are provided formally to show the efficiency of the proposed method.
Operation Research
Alireza Alinezhad; abolfazl kazemi; Mojgan Khorasani
Volume 13, Issue 1 , Spring 2021
Abstract
This paper proposes a satisfying optimization method for fuzzy multiple objective optimization problem. Actually, the presented method realizes the trade-off between optimization and fuzzy importance requirement. Generally, the main aim of the presented approach is to make the more important objective ...
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This paper proposes a satisfying optimization method for fuzzy multiple objective optimization problem. Actually, the presented method realizes the trade-off between optimization and fuzzy importance requirement. Generally, the main aim of the presented approach is to make the more important objective achieving the higher desirable satisfying degree. In practice, vagueness and imprecision of the goals, constraints and parameters in this problem make the decision-making complicated for decision makers who have to deal with the parameters to make the optimized decision. Hence, the reformulated optimization models based on goal programming is proposed for different fuzzy relations and fuzzy importance. In fact, decision makers can select the appropriate alternative considering their determinations from variety of solutions using parameter λ. Applying the proposed model, not only the satisfying results of all the objectives can be acquired, but also the fuzzy importance requirement can be simultaneously actualized. In addition, a numerical example is provided to illustrate how the model is applied. Finally, the conclusions and recommendations are presented.
Data Envelopment Analysis
Saeid Shahghobadi
Volume 13, Issue 1 , Spring 2021
Abstract
There are different approaches to generate a common set of weights in DEA based on the p - distance measure. Deviation of an efficiency score derived from a CSW from target efficiency score may be related to the model and the parameter p. In this study, we try to clarify points about choosing p, model, ...
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There are different approaches to generate a common set of weights in DEA based on the p - distance measure. Deviation of an efficiency score derived from a CSW from target efficiency score may be related to the model and the parameter p. In this study, we try to clarify points about choosing p, model, and data set if it is necessary to produce an efficiency score with the least deviation by a CSW. Two improved linear models are developed by analyzing the result of available models. The results of the proposed models have smaller individual and overall efficiency than corresponding prior ones that It has been confirmed with numerical examples and simulation analysis.
Data Envelopment Analysis
Ehsan Zanboori; fatemeh Rostami; Saeid Ghobadi
Volume 13, Issue 1 , Spring 2021
Abstract
This paper evaluates the relative performance of open source software projects by evaluating multiple project inputs and multiple project outputs by using data envelopment analysis (DEA) model. The DEA model produces an efficiency score for each project based on project inputs and outputs. One of the ...
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This paper evaluates the relative performance of open source software projects by evaluating multiple project inputs and multiple project outputs by using data envelopment analysis (DEA) model. The DEA model produces an efficiency score for each project based on project inputs and outputs. One of the important issues in data envelopment analysis is ranking DMUs. In this paper, open source software projects (OSS) are considered as decision making units which consume inputs to generate outputs. In this article, three standard Data Envelopment Analysis (DEA) models are used to evaluate the open source software projects. Also, super-efficiency model are used for ranking. Due to the inability of the models to rank projects, the AP-super efficiency model (the most important and popular method for ranking units) has been used for ranking OSS projects.The result of this research is a practical model that can be used by OSS project developers in order to evaluate the relative performance of their projects and make decision for their sources. Also, OSS projects can now be adequately ranked and evaluated according to project performance.
Numerical Analysis
ABD'GAFAR TUNDE TIAMIYU; Abosede Temilade COLE; KHADEEJAH JAMES AUDU
Volume 13, Issue 1 , Spring 2021
Abstract
We propose a new self-starting sixth-order hybrid block linear multistep method using backward differentiation formula for direct solution of third-order differential equations with either initial conditions or boundary conditions. The method used collocation and interpolation techniques with three off-step ...
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We propose a new self-starting sixth-order hybrid block linear multistep method using backward differentiation formula for direct solution of third-order differential equations with either initial conditions or boundary conditions. The method used collocation and interpolation techniques with three off-step points and five-step points, choosing power series as the basis function. The convergence of the method is established, and three numerical experiments of initial and boundary value problems are used to demonstrate the efficiency of the proposed method. The numerical results in Tables and Figures show the efficiency of the method. Furthermore, the numerical method outperformed the results from existing literature in terms of accuracy as evident in the results of absolute errors produced.
Numerical Analysis
KHADEEJAH JAMES AUDU; Yusuph Amuda Yahaya; Rufus Kayode Adeboye; Usman Yusuf Abubakar
Volume 13, Issue 1 , Spring 2021
Abstract
In this paper, we propose some necessary conditions for convergence of Triple Accelerated Over-Relaxation (TAOR) method with respect to $M-$ coefficient matrices. The theoretical approach for the proofs is analyzed through some standard procedures in the literature. Some numerical experiments are performed ...
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In this paper, we propose some necessary conditions for convergence of Triple Accelerated Over-Relaxation (TAOR) method with respect to $M-$ coefficient matrices. The theoretical approach for the proofs is analyzed through some standard procedures in the literature. Some numerical experiments are performed to show the efficiency of our approach, and the results obtained compared favourably with those obtained through the existing methods in terms of spectral radii of their iteration matrices.
Supply Chain Management
Sirous Balaei; Nabiollah Mohammadi; Homa Doroudi
Volume 13, Issue 1 , Spring 2021
Abstract
The present research aims to identify the factors affecting the green supply chain in the steel industry with a combined approach. The research is an applied study in type, an exploratory study in goal, a quantitative and qualitative study in data type, and a field study in procedure, in which questionnaire ...
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The present research aims to identify the factors affecting the green supply chain in the steel industry with a combined approach. The research is an applied study in type, an exploratory study in goal, a quantitative and qualitative study in data type, and a field study in procedure, in which questionnaire and interview were used as the research instrument. The statistical population was composed of the experts of the steel industry, out of whom 25 experts were selected as the statistical sample by the purposive technique. Data were analyzed by the fuzzy DEMATEL and fuzzy network process analysis in the SPSS21 and MS-Excel software packages. Then, the fuzzy Delphi technique was used, resulting in the identification of five criteria and 25 subcriteria. Then, the fuzzy DEMATEL was employed to determine the influence and dependence of the factors according to which among the main factors, the environment factor was the most influential with an influence value of 0.792 and the financial factor was the most dependent factor with a net dependence value of -0.996. Also, the identified factors were ranked by the fuzzy analytical network process. The results show that the financial factor has the highest weight. Also, the other factors are in the order of environmental, quality, environment, and technology in terms of importance.
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