18 research outputs found

    Analysis of diffusion process in fractured reservoirs using fractional derivative approach

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    The fractal geometry is used to model of a naturally fractured reservoir and the concept of fractional derivative is applied to the diffusion equation to incorporate the history of fluid flow in naturally fractured reservoirs. The resulting fractally fractional diffusion (FFD) equation is solved analytically in the Laplace space for three outer boundary conditions. The analytical solutions are used to analyze the response of a naturally fractured reservoir considering the anomalous behavior of oil production. Several synthetic examples are provided to illustrate the methodology proposed in this work and to explain the diffusion process in fractally fractured systems

    Fractional Order Version of the HJB Equation

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    We consider an extension of the well-known Hamilton-Jacobi-Bellman (HJB) equation for fractional order dynamical systems in which a generalized performance index is considered for the related optimal control problem. Owing to the nonlocality of the fractional order operators, the classical HJB equation, in the usual form, does not hold true for fractional problems. Effectiveness of the proposed technique is illustrated through a numerical example.Comment: This is a preprint of a paper whose final and definite form is with 'Journal of Computational and Nonlinear Dynamics', ISSN 1555-1415, eISSN 1555-1423, CODEN: JCNDDM. Submitted 28-June-2018; Revised 15-Sept-2018; Accepted 28-Oct-201

    Control of a novel chaotic fractional order system using a state feedback technique

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    We consider a new fractional order chaotic system displaying an interesting behavior. A necessary condition for the system to remain chaotic is derived. It is found that chaos exists in the system with order less than three. Using the Routh-Hurwitz and the Matignon stability criteria, we analyze the novel chaotic fractional order system and propose a control methodology that is better than the nonlinear counterparts available in the literature, in the sense of simplicity of implementation and analysis. A scalar control input that excites only one of the states is proposed, and sufficient conditions for the controller gain to stabilize the unstable equilibrium points derived. Numerical simulations confirm the theoretical analysis. © 2013 Elsevier Ltd. All rights reserved

    Fractional Order Models of Industrial Pneumatic Controllers

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    This paper addresses a new approach for modeling of versatile controllers in industrial automation and process control systems such as pneumatic controllers. Some fractional order dynamical models are developed for pressure and pneumatic systems with bellows-nozzle-flapper configuration. In the light of fractional calculus, a fractional order derivative-derivative (FrDD) controller and integral-derivative (FrID) are remodeled. Numerical simulations illustrate the application of the obtained theoretical results in simple examples

    Classification of White Blood Cells in Peripheral Blood Sample using Convolutional Neural Network

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    Background: Observation, categorize and count various types of white blood cells in a blood sample is a One of the most important steps in the treatment of various diseases. The aim of this study was to design and implement a fast and reliable and based on the processing of microscopic images of blood samples for the classification of four types of white blood cells. Materials and Methods: In this article, the modified k-means clustering method is used to perform image segmentation. Furthermore, The classification of white blood cells was done using a deep convolutional neural network and with the help of data in the MISP database, a free database composed of microscopic blood sample images. Moreover, Several regularization techniques such as dropout and image augmentation were applied to prevent the network from overfitting. Results: In the classification category, the accuracy of the neural network is measured to be 99%, which has been more successful than many earlier studies. In the segmentation section, the cross-reference index was 0.73. Conclusion: The results of this research show that rapid and reliable system design and implementation is possible by processing the microscopic images of the blood sample using different methods of image processing and machine learning

    Analytical Solution of Fractional Order Diffusivity Equation With Wellbore Storage and Skin Effects

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    This paper addresses the model, solution, and analysis of fluid flow behavior in fractal reservoirs considering wellbore storage and skin effects (WS–SE). In the light of the fractional calculus (FC), the general form of fluid flow model considering the history of flow in all stages of production is presented. On the basis of Bessel functions theory, analytical solutions in the Laplace transform domain under three outer-boundary conditions, assuming the well is producing at a constant rate, are obtained. Based on the analytical solutions, various examples, discussing the pressure-transient behavior of a well in a fractal reservoir, are presented.info:eu-repo/semantics/publishedVersio
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