Research Article
Sayyed Hossein Ejtahed; Naser Pariz; Ali Karimpour
Abstract
Switched linear systems are noted as a major category of control systems. Fault detection of these systems is affected by switching phenomena and therefore their integrated fault detection and robust control (IFDRC) are the central issues of recent studies. Existing studies on IFDRC ...
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Switched linear systems are noted as a major category of control systems. Fault detection of these systems is affected by switching phenomena and therefore their integrated fault detection and robust control (IFDRC) are the central issues of recent studies. Existing studies on IFDRC do not consider the effects of all of the parameter uncertainties, input disturbance, and mode-dependent time-varying state delay in the presence of mode-dependent average dwell time (MDADT) switching together in these systems. To address the issue based on output feedback, in this paper, the IFDRC design problem is formulated as a multi-objective or mixed H∞/H- optimization problem. H∞ performance indicator guarantees the robustness of residual to disturbance, and H- performance represents the sensitivity index of residual to the fault. A piecewise Lyapunov-Krasovskii function is employed together with the MDADT scheme and therefore, sufficient conditions are derived in terms of linear matrix inequalities (LMIs) in order to deal with the problem. Then to clarify the design procedure, we also present an algorithm in the light of the proposed approach. Eventually, to illustrate the efficiency of the suggested approach, the designed IFDRC framework is simulated for a case study of an Electrical Circuit system.
Research Article
Kobra Mohammadsalahi; Farzin Modarres Khiyabani; Nima Azarmir Shotorbani
Abstract
This paper presents a capable recurrent neural network, the so-called µRNN for solving a class of non-convex quadratic programming problems. Based on the optimality conditions we construct a new recurrent neural network (µRNN), which has a simple structure and its capability ...
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This paper presents a capable recurrent neural network, the so-called µRNN for solving a class of non-convex quadratic programming problems. Based on the optimality conditions we construct a new recurrent neural network (µRNN), which has a simple structure and its capability is preserved. The proposed neural network model is stable in the sense of Lyapunov and converges to the exact optimal solution of the original problem. In a particular case, the optimality conditions of the problem become necessary and sufficient. Numerical experiments and comparisons with some existing algorithms are presented to illustrate the theoretical results and show the efficiency of the proposed network.
Research Article
Mahdi Ahmadnia; Reza Ghanbari; Khatere Ghorbani-Moghadam
Abstract
In a water distribution network, in order to analyze and determine its parameters such as head and flow rate, we have to solve nonlinear hydraulic equations in each component of the network. Contrary to most of the water distribution network simulation software, solving ...
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In a water distribution network, in order to analyze and determine its parameters such as head and flow rate, we have to solve nonlinear hydraulic equations in each component of the network. Contrary to most of the water distribution network simulation software, solving these equations by using the gradient method, we propose a trust-region method to solve them, as the trust-region method is newer than the gradient method and has well worked in mathematical problems. To prove the effectiveness of our method, we made a comparison between our proposed method and the well-known gradient method. The results show that the trust-region method is convergent in all instances, but the gradient method diverges when the dimension of nonlinear hydraulic equations of water distribution networks increases. In addition, our results convince the solution obtained from the trust-region method is more accurate compared to the gradient method. Thus, using the trust-region method in solving the network equations can lead to a better hydraulic analysis of the network.
Research Article
Yousef Edrisi-Tabriz
Abstract
In this paper, we present a numerical method for solving the fractional optimal control problems in which fractional integral operational matrices of basic B-spline functions are used. In the proposed method, we use the Riemann-Liouville fractional integral. With ...
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In this paper, we present a numerical method for solving the fractional optimal control problems in which fractional integral operational matrices of basic B-spline functions are used. In the proposed method, we use the Riemann-Liouville fractional integral. With the help of the operational matrix of the fractional integral and the collocation method, we transform the fractional optimal control problem into a nonlinear programming problem and then solve it with an appropriate optimization algorithm. Compared to similar numerical techniques, our method has better accuracy and efficiency, and also it is easy to use. To provide a clear view of the applicability and efficiency of our numerical method, several illustrative examples are presented.
Research Article
Javad Mahdavi Varaki; Iraj Mahdavi; Shahrzad Mirkarimi
Abstract
Social, economic, and environmental issues such as population growth, reduction of natural resources, climate change, market fluctuations, and changing consumer behavior have attracted the attention of politicians to the supply chain of agricultural ...
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Social, economic, and environmental issues such as population growth, reduction of natural resources, climate change, market fluctuations, and changing consumer behavior have attracted the attention of politicians to the supply chain of agricultural products. Designing an effective supply chain for each product can lead to optimal management of the agricultural sector and create coordination and links between activities. In this article, the design of a two-echelon supply chain network of shrimp in Golestan province is investigated. The objective is to minimize the total cost associated with fixed opening and operating costs of shrimp farming companies and to determine the target market for these producers. Also, this study involves deciding on the amount of inputs purchased by each company and determining the best mode of transport. To characterize and solve this problem, we developed a mixed-integer programming (MIP) model that solves with GAMS software. The results show that with the implementation of the MIP model, the total costs of the chain are reduced by nearly 20 percent compared to the current situation. In addition, without increasing production, it is possible to supply 0.053 percent of global market demand, which is 76 percent more than before.
Research Article
Fatemeh Babakordi; Tofigh Allahviranloo
Abstract
Solving fuzzy linear systems has been widely studied during the last decades. However, there are still many challenges to solving fuzzy linear equations, as most of the studies have used the principle of extension, which suffers from shortcomings such as the lack ...
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Solving fuzzy linear systems has been widely studied during the last decades. However, there are still many challenges to solving fuzzy linear equations, as most of the studies have used the principle of extension, which suffers from shortcomings such as the lack of solution, achieving solutions under very strong conditions, large support of the obtained solutions, inaccurate or even incorrect solutions due to not utilizing all the available information, complicated process and high computational load. These problems motivated us to present a fuzzy Cramer method for solving fuzzy linear equations, which uses arithmetic operations based on the Transmission Average (TA). In this study, fully fuzzy linear systems in the form of $ \tilde{A}\tilde{X}=\tilde{B} $, and dual fuzzy linear systems in the form of $ \tilde{A}\tilde{X}+\tilde{B}=\tilde{C}\tilde{X}+\tilde{D} $ are solved using the proposed fuzzy Cramer method, and numerical examples are provided to confirm the effectiveness and applicability of the proposed method.
