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Asynchronous Distributed Control of Biogas Supply and Multienergy Demand

IEEE TRANSACTIONS ON AUTOMATION SCIENCE AND ENGINEERING 2017年第2期14卷 558-572页

作者： Alkano, Desti Scherpen, Jacquelien M. A. Chorfi, Younes Univ Groningen Fac Math & Nat Sci NL-9747 AG Groningen Netherlands

In this paper, we study the coordination between biogas producers who can use the biogas themselves, exchange biogas with their neighbors, or deliver it to the various energy grids, such as the low pressure gas grid or the power grid. These producers are called prosumers. In this setting, gas storage, fuel cells, microcombined heat power systems, and heat buffers are all part of the prosumers' node. We aim to optimize the imbalance, profit, and comfort levels per prosumer, while taking the constraints of the energy grids into account and while allowing prosumers to exchange energy with each other. This results in a two-layer optimization problem formulation. In addition, in practice, the communication between prosumers among each other and with grid operators is done in an asynchronous manner. In this paper, we study the problem of two-layer optimization for biogas prosumers embedded in multiple energy grids, while the (bidirectional) communication between the various partners is done asynchronously. We prove the convergence of the asynchronous coordination algorithm that uses both the inputs and the states. We conduct simulations for the biogas prosumer setting, using realistic data to illustrate the convergence of the algorithm and to study its practical implementation.

关键词： Cooperative systems decentralized energy storage distributed asynchronous flexible demand gradient algorithm multienergy carrier network congestion control

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On a numerical approach for solving some geometrical shape optimization problems in fluid mechanics

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COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION 2024年 128卷

作者： Chakib, Abdelkrim Khalil, Ibrahim Ouaissa, Hamid Sadik, Azeddine Sultan Moulay Slimane Univ Fac Sci & Tech Appl Math Team AMT Beni Mellal Morocco Abdelmalek Essaadi Univ Normal Higher Sch Appl Math & Comp Sci Team AMCST Tetouan Morocco

This paper is devoted to the numerical study of geometrical shape optimization problems in fluid mechanics, which consist in minimizing some criterion volume cost functionals on a family of admissible doubly connected domains, constrained by steady-state Stokes boundary value problems. We establish the existence of the shape derivative of the considered cost functionals, by means of Minkowski deformation, using the shape derivative formulas, recently established in Boulkhemair and Chakib (2014). This allows us to express the shape derivative by means of the support function and to avoid the tedious computations required when one use the gradient optimization process based on the classical shape derivative, involving the vector fields, notably when one opt for the finite element discretization. So, based on the established shape derivative formulas, we propose a shape optimization numerical process for solving these problems, using the gradient descent algorithm performed by the finite element discretization, for approximating the auxiliary boundary value Stokes problems. Finally, in order to show the validity and the effectiveness of the proposed approach, we present some numerical tests obtained by solving some shape optimization problems of minimizing different cost functionals on various configurations of domains, constrained by steady-state stokes boundary value problems with different boundary conditions. These numerical simulations include some comparison results showing that the proposed approach is more efficient than the gradient approach based on the classical shape derivative, in terms of the accuracy of the solution and central processing unit (CPU) time execution.

关键词： Shape optimization Fluid mechanics Stokes equation Shape derivative Doubly connected domains Minkowski deformation Convex domains Support functions gradient algorithm Finite elements approximation

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Shape optimization for Stokes flow

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APPLIED NUMERICAL MATHEMATICS 2008年第6期58卷 827-844页

作者： Gao, Zhiming Ma, Yichen Zhuang, Hongwei Xian Jiaotong Univ Sch Sci Xian 710049 Shaanxi Peoples R China

This paper is concerned with a shape, sensitivity analysis of a viscous incompressible fluid driven by Stokes equations. The structures of continuous shape gradients with respect to the shape of the variable domain for some given cost functionals are established by introducing the Piola transformation and then deriving the state derivative and its associated adjoint state. Finally we give the finite element approximation of the problem and a gradient type algorithm is effectively used for our problem. (C) 2007 IMACS. Published by Elsevier B.V. All rights reserved.

关键词： shape optimization shape derivative gradient algorithm Stokes equations

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Shape optimization for Navier-Stokes flow

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INVERSE PROBLEMS IN SCIENCE AND ENGINEERING 2008年第5期16卷 583-616页

作者： Gao, Z. M. Ma, Y. C. Zhuang, H. W. Xian Jiaotong Univ Sch Sci Shaanxi 710049 Peoples R China Engn Coll Armed Police Force Shaanxi 710086 Peoples R China

This article describes the optimal shape design of the newtonian viscous incompressible fluids driven by the stationary nonhomogeneous Navier-Stokes equations. We use three approaches to derive the structures of shape gradients for some given cost functionals. The first one is to use the Piola transformation and derive the state derivative and its associated adjoint state;the second one is to use the differentiability of a minimax formulation involving a Lagrangian functional with a function space parametrization technique;the last one is to employ the differentiability of a minimax formulation with a function space embedding technique. Finally, we apply a gradient type algorithm to our problem and numerical examples show that our theory is useful for practical purpose and the proposed algorithm is feasible.

关键词： shape optimization shape derivative gradient algorithm minimax formulation material derivative Navier-Stokes equations

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DESIGN OF IIR GROUP DELAY EQUALIZERS

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ELECTRONICS LETTERS 1990年第3期26卷 200-202页

作者： LOPRESTI, L VISINTIN, M Dipartimento di Elettronica Politecnico di Torino Italy

The authors describe a method for equalising group delay distortion through a cascade of second-order IIR allpass filters. The filter design is performed using the gradient algorithm, to get the set of poles that mini... 详细信息

关键词： IIR group delay equalisers all-pass filters cascade cascade networks delay circuits digital filters digital filters equalisers filter design filtering and prediction theory gradient algorithm network synthesis poles poles and zeros second-order IIR allpass filters

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Analytical Modeling Approach to Detect Magnet Defects in Permanent-Magnet Brushless Motors

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IEEE TRANSACTIONS ON MAGNETICS 2008年第12期44卷 4599-4604页

作者： Farooq, J. A. Djerdir, A. Miraoui, A. Univ Technol Belfort Montbeliard SET Lab Elect Engn & Control Syst Dept F-90000 Belfort France

The paper presents a novel approach to detect magnet faults such as local demagnetization in brushless permanent-magnet motors. We have developed a new form of analytical model that solves the Laplacian/quasi-Poissonian field equations in the machine's air-gap and magnet element regions. We verified the model by using finite-element software in which demagnetization faults were simulated and electromotive force was calculated as a function of rotor position. We then introduced the numerical data of electromotive force into a gradient-based algorithm that uses the analytical model to locate demagnetized regions in the magnet as simulated in the finite-element package. The fast and accurate convergence of the algorithm makes the model useful in magnet fault diagnostics.

关键词： Analytical model finite-element analysis gradient algorithm permanent-magnet machine

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Adaptive IIR notch filters based on new error criteria

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SIGNAL PROCESSING 2008年第3期88卷 685-703页

作者： Punchalard, R. Lorsawatsiri, A. Koseeyaporn, J. Wardkein, P. Roeksabutr, A. Mahanakorn Univ Technol Dept Telecommun Engn Bangkok 10530 Thailand King Mongkuts Inst Technol Ladkrabang Fac Engn Dept Telecommun Engn Bangkok 10520 Thailand

Modified indirect and direct plain gradient (MIPG and MDPG) algorithms using new error criteria for second-order adaptive IIR (infinite-impulse response) notch filters (ANFs) with constrained poles and zeros are proposed in this paper. The proposed techniques are based on modifying error functions of the standard indirect and direct ANFs. In this work, the proposed error criteria are modified as the mean value of the product of the two signals which are, respectively, produced by the FIR (finite-impulse response) and IIR sections of the ANFs. Due to a non-zero slope straight line-like characteristic of the new cost functions, the gradient based adaptive algorithm rapidly converges to an optimum solution resulting in faster convergence speed than that of the conventional method. The closed form expressions for steady-state estimation bias and mean square error (MSE) of the proposed algorithms are also carried out. In addition, extensive simulations of the proposed algorithms compared to other methods are provided to support the theoretical analyses. Although, there are some limitations in the proposed algorithms, however, the demonstrated results obtained from tested algorithms at the same condition confirm that the proposed MIPG and MDPG algorithms are superior to others in convergent speed. (C) 2007 Elsevier B.V. All rights reserved.

关键词： adaptive IIR notch filter gradient algorithm new error criteria

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Adaptive wavetable oscillators

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2007年第9期55卷 4382-4392页

作者： Arora, Raman Sethares, William A. Univ Wisconsin Dept Elect & Comp Engn Madison WI 53706 USA

An adaptive oscillator is a system that can lock on to a time-varying input signal, synchronizing its output to both the frequency and phase of the input. A wavetable oscillator generates a periodic output by indexing into a lookup table that stores a single period of the waveform. An adaptive wavetable oscillator (AWO) combines these two ideas in a technique which, separates the periodic output waveform from the parameters that control the adaptation of the frequency and phase of the waveform. This separation is advantageous because it decouples the state of the oscillator from the dynamics of the adaptation, allowing the process of synchronization to be interpreted as a simple gradient optimization on a cost function. The oscillations remain stable over a large and easily described range of parameter values, and analysis of the synchronization can proceed along lines familiar from standard adaptive systems. Key issues in the design of AWOs are: the class of admissible inputs, the shape of the wavetable, the parameters that will be controlled, and the adaptive algorithm that adjusts the parameters. This paper examines these issues through analysis and simulation, focusing on conditions that achieve the desired synchronization between output and input.

关键词： adaptive systems dynamics of adaptation gradient algorithm lookup table mode locking phase-locked loop synchronization

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Two-stage adaptive estimation of irrational linear systems

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2017年 78卷 213-219页

作者： Kapetina Mirna, N. Rapaic Milan, R. Jelicic Zoran, D. Univ Novi Sad Fac Tech Sci Trg Dositeja Obradovica 6 Novi Sad Serbia

In the present paper, an adaptive parameter estimation algorithm applicable to linear systems with transfer functions of arbitrary structure is proposed. The approach can be applied to a wide class of linear processes, including non-linearly parameterized ones. The proposed method is applicable to fractional-order systems, distributed-parameter and delayed systems, and other classes of systems described by irrational transfer functions. In the first stage of the proposed procedure, values of the transfer function at specific frequencies are pinpointed by means of the Recursive Least Square algorithm with forgetting factor. In the second stage, the unknown parameters are found by numerically inverting complex non-linear relations linking them to the quantities estimated in the first stage. The inversion is performed by means of an iterative, gradient-based scheme. The method is illustrated by several detailedly explained numerical examples. (C) 2017 Elsevier GmbH. All rights reserved.

关键词： Adaptive parameter estimation Fractional order systems Distributed parameter systems Delayed systems Recursive Least Square gradient algorithm

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Optimizing and assigning price levels for air traffic management

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TRANSPORTATION RESEARCH PART E-LOGISTICS AND TRANSPORTATION REVIEW 2002年第3-4期38卷 221-237页

作者： Deschinkel, K Farges, JL Delahaye, D Off Natl Etud & Rech Aerosp CERT F-31055 Toulouse France Univ Paris 01 CERMSEM F-75013 Paris France LOG F-31055 Toulouse France CENA F-31055 Toulouse France

Pricing policies could encourage airline companies to modify departure times and routes of their flights in order to reach a route-slot allocation target that minimizes the en-route congestion. The problem of restricting the number of price levels and the assignment of one price level to each sector at each time period is studied using a simulation based on a Logit discrete choice model. In this model, an option is defined as the combination of a departure time and a route. For each flight, a utility is associated to each option and takes into account the flying cost, the cost of ground delay and the prices of crossed sectors. The optimization of the pricing policy considers average flows and minimizes the quadratic difference between desired and expected flows on each option. A heuristic algorithm that involves successive iterations of simulated annealing and gradient methods performs this optimization. The simulated annealing assigns a price level to each sector at each time period, and the gradient algorithm computes new values of price levels. The test of the method on constructed examples indicates that the use of only four price levels does not significantly deteriorate the performance of the system with respect to the use of independent prices. (C) 2002 Elsevier Science Ltd. All rights reserved.

关键词： air traffic pricing policies simulated annealing gradient algorithm

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