Iranian Journal of Optimization: 2 (2)

Open Access Article

1 - Analysis of environmental efficiency and marginal rate of substitution in the presence of undesirable factors: A DEA-based approach
منصور صوفی فاطمه بزرگی گردویشه مهدی همایون فر علیرضا امیرتیموری

The balance between environmental regulations and economic issues has always been one of the main challenges of governments, because with the growth of industrialization, environmental pollution has also increased. Along with the desired outputs in the production proces More

The balance between environmental regulations and economic issues has always been one of the main challenges of governments, because with the growth of industrialization, environmental pollution has also increased. Along with the desired outputs in the production process, may also produce undesirable outputs which have a great impact on organizations efficiency and environmental pollution. On the other hand, dealing with the impact of undesirable factors on the inputs and desirable outputs, valuable information for making strategies and organizational decisions could be achieved. Considering undesirable factors, this paper aims to calculate the relative efficiency and marginal ratios of environmental systems using weak and managerial disposability models of data envelopment analysis (DEA). This study is conducted in two phases. In the first one, the regions were classified into efficient and inefficient groups using a developed DEA model. In the second step, the marginal rate of undesirable outputs on the inputs and desirable outputs in efficient areas were calculated. The results showed that the change in the amount of undesirable outputs has a significant effect on other variables. Manuscript profile

Open Access Article

2 - A Constructive Scheme for Tripled Fixed Point Problems in Hilbert Space
Samuel Aniki

Tripled fixed point is an extension to coupled fixed point theory. The idea of tripled fixed point has largely become a focus of research interest in the area of mathematical analysis, especially for their vast application. This research presents a common tripled fixed More

Tripled fixed point is an extension to coupled fixed point theory. The idea of tripled fixed point has largely become a focus of research interest in the area of mathematical analysis, especially for their vast application. This research presents a common tripled fixed point iteration for approximating tripled fixed points in linear spaces which is in the context of a Hilbert space. Here, a tripled Mann iterative scheme is defined and applied to resolve the problem of common tripled fixed points of certain mappings. Hence, this work is an extension to recent research in the literature. Manuscript profile

Open Access Article

3 - Non-dominated DEA cross efficiency scores; a secondary goal approach
سعید شاه قبادی عباس قماشی فرهاد مرادی

Data envelopment analysis (DEA) is a non-parametric programming method for evaluating the relative efficiency of a set of peer decision-making units (DMUs) with multiple inputs and multiple outputs. The DEA cross-efficiency method is a well-known method that use to eval More

Data envelopment analysis (DEA) is a non-parametric programming method for evaluating the relative efficiency of a set of peer decision-making units (DMUs) with multiple inputs and multiple outputs. The DEA cross-efficiency method is a well-known method that use to evaluate and ranking a set of peer decision-making units. Whenever a DMU intends to evaluate other DMUs, it faces the problem of non-uniqueness optimal weights of DEA models. Because different weights give us different cross-scores and subsequently different cross-efficiencies scores and this will confuse the decision-maker to make an ultimate decision. The main drawback of this method is the alternate optimal solution set of the DEA model. The main purpose of this study is to propose an approach to this problem to generate non-dominated DEA cross-efficiency scores. We propose a linear programming secondary goal model to select a set of optimal weights for each DMU. Our proposed method is not only simpler than other methods presented with the same purpose, but also does not go beyond the main method. Manuscript profile

Open Access Article

4 - Eco-Efficiency in two-stage structure;A DDF Approach
منیره ذریه حبیب مهناز مقبولی

The importance of environment protection always raises a considerable among the researchers especially when pollutant and undesirable outputs are present. The non-parametric Data Envelopment Analysis (DEA) literature on network-structured performance analysis normally f More

The importance of environment protection always raises a considerable among the researchers especially when pollutant and undesirable outputs are present. The non-parametric Data Envelopment Analysis (DEA) literature on network-structured performance analysis normally fail to express the undesirable intermediate production in the process. From the production efficiency point of view, symmetrically handling both of the desirable and the undesirable outputs in the assessment process in the two stage network structure is developed in this paper. The motivation of this study is the application of the directional distance function (DDF) to modeling the two-stage network structure with the undesirable intermediate measures upon employing Stackelberg theory. A real case on the thirteen poultry units in Iran has been illustrated to verify the applicability of the proposed approach. Manuscript profile

Open Access Article

5 - Numerical Solution of Fokker-Planck-Kolmogorov Time Fractional Differential Equations Using Haar Wavelet Method and convergence and error analysis
شعبان محمدی S. Reza Hejazi

The purpose of this paper is to present an efficient numerical method for finding numerical solutions Fokker-Planck-Kolmogorov time-fractional differential equations. The Haar Wave was the first to be introduced. The Fokker-Planck-Kolmogorov time-fractional differential More

The purpose of this paper is to present an efficient numerical method for finding numerical solutions Fokker-Planck-Kolmogorov time-fractional differential equations. The Haar Wave was the first to be introduced. The Fokker-Planck-Kolmogorov time-fractional differential equation is converted to the linear equation using the Haar wavelet operation matrix in this technique. This method has the advantage of being simple to solve. The simulation was carried out using MATLAB software. Finally, the proposed strategy was used to solve certain problems. The results revealed that the suggested numerical method is highly accurate and effective when used to Fokker-Planck-Kolmogorov time fraction differential equations. The results for some numerical examples are documented in table and graph form to elaborate on the efficiency and precision of the suggested method. Moreover, for the convergence of the proposed technique, inequality is derived in the context of error analysis. Manuscript profile

Open Access Article

6 - An Artificial Neural Network Method to Predict the COVID-19 Cases in Iran
Meisam Shamsi رضا بابازاده Mohsen Varmazyar

The sudden emergence of a Coronavirus and its rapid spread due to the globalization factors, especially the airline network, provoked the reaction of countries. Governments attempt to use all available means, including prediction methods, to control the spread of the Co More

The sudden emergence of a Coronavirus and its rapid spread due to the globalization factors, especially the airline network, provoked the reaction of countries. Governments attempt to use all available means, including prediction methods, to control the spread of the Coronavirus. In this article, we have developed various models based on artificial neural networks, including multi-layer perceptron, radial basis function, and adaptive-network-based fuzzy inference system with different learning algorithms, transfer functions, membership functions, hidden layers, hidden neurons, and kernels. We have identified five factors influencing the Coronavirus outbreak based on the Pearson correlation coefficient approach. These factors are gasoline consumption, internet pressure, number of wedding ceremonies, online transactions, and mask consumption. The accuracy of the developed models is identified by calculating three types of statistical errors, including root mean square error, mean absolute error, and mean absolute percentage error. The results show that the radial basis function model predicts the number of Covid-19 cases for the one month (mid-term) with an accuracy of over 97%. This study provides an efficient approach to predict the number of COVID-19 cases which help policymakers to make strategic decisions, including closing borders, designing supply chains for medical and health equipment, and enacting new laws. Manuscript profile

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