Calculation of reference evapotranspiration (ETo) is essential in hydrology and agriculture. ETo plays an important role in planning and management of water resources and irrigation scheduling. The results of many stu...
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Calculation of reference evapotranspiration (ETo) is essential in hydrology and agriculture. ETo plays an important role in planning and management of water resources and irrigation scheduling. The results of many studies strongly support the use of the Penman-Monteith FAO 56 (PMF-56) method as the standard method of estimating ETo. The basic obstacle to using this method widely is the numerous meteorological variables required. Multilayer perceptron (MLP) networks optimized with different learning algorithms and activation functions were applied for estimating ETo in a semiarid region in Iran. Four MLP models comprising various combinations of meteorological variables are developed. The MLP model which needs all of the meteorological parameters performed best for ETo estimation amongst the other MLP models. It was also found that the ConjugateGradient, DeltaBarDelta, DeltaBarDelta and Levenberg-Marquardt were the best algorithms for training the MLP1, MLP2, MLP3 and MLP4 models, respectively.
This paper proposes and studies an algorithm for task-level control based on a radial. basis function network approximation of the optimal task input vector on parameters of the task. A learning update scheme is propo...
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This paper proposes and studies an algorithm for task-level control based on a radial. basis function network approximation of the optimal task input vector on parameters of the task. A learning update scheme is proposed for on-line compensation for the inaccuracy of the model used in the controller design. The update approximates the Jacobian of the task input-output mapping using an off-line design model. Deadzone convergence of this learning scheme in the presence of modeling errors is proved and constructive estimates of the convergence robustness parameters are obtained. An application of the proposed algorithm to Feedforward vibration compensation for flexible spacecraft slewing complements the theoretical analysis. Simulations demonstrate practically acceptable performance of the algorithms in this difficult problem. (C) 2001 Elsevier Science Ltd. All rights reserved.
The paper presents a new approach to optimize the Multilayer Perceptron Neural Network (MLPNN), to deal with the generalization problem. As known, most supervised learning algorithms aim to minimize the training error...
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The paper presents a new approach to optimize the Multilayer Perceptron Neural Network (MLPNN), to deal with the generalization problem. As known, most supervised learning algorithms aim to minimize the training error. However, the mentioned methods, based only on error minimizing, may generate a solution with an insufficient generalization performance. This present work proposes a multiobjective modelling problem involving two objectives: accuracy and complexity since the learning problem is multiobjective by nature. The learning task is carried on by minimizing both objectives simultaneously, according to Pareto domination concept, using NSGAII (Non-dominated Sorting Genetic algorithm II) as a solver. This method leads us to a set of solutions called Pareto front, being the optimal solutions set, the adequate MLPNN need to be extracted. We show empirically that the proposed method is capable of reducing the neural networks topology and improved generalization performance, in addition to a good classification rate compared to different methods. (C) 2020 Published by Elsevier B.V.
This paper puts forward an intelligent method for online voltage stability margin (VSM) assessment based on optimal fuzzy system and feature selection technique, which has excellent performance for large power systems...
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This paper puts forward an intelligent method for online voltage stability margin (VSM) assessment based on optimal fuzzy system and feature selection technique, which has excellent performance for large power systems. The proposed VSM estimation method includes three key parts: feature extraction and selection part, estimator part and training part. In this method, power system's loading parameters are used as the main input of adaptive neuro-fuzzy inference system (ANFIS) and association rules (AR) technique is used to select the most effective loading parameters. In the training part, we used Harris hawks optimization algorithm (HHOA) to train the ANFIS efficiently. Using the proposed method, the VSM can be monitored online with high precision for both small and large systems and appropriate control measures can be applied if necessary. Knowing the exact amount of VSM and applying precautionary measures can prevent from voltage collapse, heavy financial losses and power supply interruption. The proposed method tested on 39-bus, 118-bus and 300-bus IEEE test system and the MATLAB simulation results demonstrated that the propounded method has much better performance than other recently introduced VSM assessment approaches. Providing a VSM estimation method, which is effective for large power systems, selecting the most informative loading parameters and improving the ANFIS's performance using HHOA are the main contributions of this paper. (C) 2020 ISA. Published by Elsevier Ltd. All rights reserved.
In this paper, a novel fractional-order adaptive controller is presented for a class of nonlinear systems with unknown dynamics. The dynamics of the system is considered to be fully unknown. The multi-layer perceptron...
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In this paper, a novel fractional-order adaptive controller is presented for a class of nonlinear systems with unknown dynamics. The dynamics of the system is considered to be fully unknown. The multi-layer perceptron (MLP) neural network using restricted Boltzmann machine (RBMs) is employed for online dynamic identification. A deep learning method on the basis of contrastive divergence (CD) algorithm combined with the extended Kalman filter (EKF) is proposed for online optimisation. The proposed controller has two parts. The first part is a simple error feedback controller and the second one is the suggested DT2-FLS. The parameters of DT2-FLS are tuned such that a cost function of tracking error to be minimised and the closed-loop system to be stable. For the best knowledge of the authors, for the first time the tuning rules for the membership function and rule parameters of DT2-FLS are derived by error feedback learning method. The closed-loop stability is demonstrated with Lyapunov method and the well performance of the schemed controller is shown by applying on the induction motor and brushless DC motors. In addition to unknown dynamics, some disturbances are also considered such as abruptly changes in load torque and time-varying rotor resistance. Furthermore, the performance of the suggested scheme is compared with some popular controllers and FLSs.
This study presents a self-evolving probabilistic fuzzy (PF) neural network with asymmetric membership function (SPFNN-AMF) controller for the position servo control of a permanent magnet linear synchronous motor (PML...
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This study presents a self-evolving probabilistic fuzzy (PF) neural network with asymmetric membership function (SPFNN-AMF) controller for the position servo control of a permanent magnet linear synchronous motor (PMLSM) servo drive system. In the beginning, the dynamic model for the PMLSM is analysed on the basis of field-oriented control. Subsequently, an SPFNN-AMF control system, which integrates the advantages of self-evolving NN, PF logic system, and AMF, is proposed to handle vagueness, randomness, and time-varying uncertainties of the PMLSM servo drive system during the control process. For the SPFNN-AMF, the proposed learning algorithm consists of the structure learning and parameter learning in which the former is used to grow and prune the fuzzy rules automatically, whereas the latter is utilised to train the network parameters dynamically. Finally, detailed experimental results of two position commands tracking at different operation conditions demonstrate the validity and robustness of the proposed SPFNN-AMF for controlling the PMLSM servo drive system.
We propose an efficient alternative to multi-layer perceptron (MLP): two-layer periodic perceptron (PP). We prove then that PP can compute every binary boolean function, we give an efficient learning algorithm for PP ...
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We propose an efficient alternative to multi-layer perceptron (MLP): two-layer periodic perceptron (PP). We prove then that PP can compute every binary boolean function, we give an efficient learning algorithm for PP and test it on academic and realistic problems. (C) 2000 Elsevier Science B.V. All rights reserved.
The semiparametric statistical model is used to formulate the problem of blind source separation. The method of estimating functions is applied to this problem, It is shown that an estimator of the mixing matrix or it...
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The semiparametric statistical model is used to formulate the problem of blind source separation. The method of estimating functions is applied to this problem, It is shown that an estimator of the mixing matrix or its learning version can be described in terms of an estimating function. The statistical efficiencies of these algorithms are studied. The main results are as follows. 1) The space consisting of all the estimating functions is derived. 2) The spare is decomposed into the orthogonal sum of the admissible part and redundant ancillary part. For any estimating function, one can find a better or equally good estimator in the admissible part. 3) The Fisher efficient (that is, asymptotically best) estimating functions are derived4) The stability of learning algorithms is studied.
For accelerating the supervised learning by the SpikeProp algorithm with the temporal coding paradigm in spiking neural networks (SNNs), three learning rate adaptation methods (heuristic rule, delta-delta rule, and de...
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For accelerating the supervised learning by the SpikeProp algorithm with the temporal coding paradigm in spiking neural networks (SNNs), three learning rate adaptation methods (heuristic rule, delta-delta rule, and delta-bar-delta rule), which are used to speed up training in artificial neural networks, are used to develop the training algorithms for feedforward SNN. The performance of these algorithms is investigated by four experiments: classical XOR (exclusive or) problem, Iris dataset, fault diagnosis in the Tennessee Eastman process, and Poisson trains of discrete spikes. The results demonstrate that all the three learning rate adaptation methods are able to speed up convergence of SNN compared with the original SpikeProp algorithm. Furthermore, if the adaptive learning rate is used in combination with the momentum term, the two modifications will balance each other in a beneficial way to accomplish rapid and steady convergence. In the three learning rate adaptation methods, delta-bar-delta rule performs the best. The delta-bar-delta method with momentum has the fastest convergence rate, the greatest stability of training process, and the maximum accuracy of network learning. The proposed algorithms in this paper are simple and efficient, and consequently valuable for practical applications of SNN.
In this study, a self-organizing interval type-3 fuzzy logic system (SO-IT3FLS) with a new learning algorithm is presented. An adaptive kernel size using fuzzy systems is introduced to improve the robustness of conven...
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In this study, a self-organizing interval type-3 fuzzy logic system (SO-IT3FLS) with a new learning algorithm is presented. An adaptive kernel size using fuzzy systems is introduced to improve the robustness of conventional correntropy based Kalman filters against non-Gaussian noise. The maximum correntropy Kalman filter (MCKF) and maximum correntropy unscented Kalman filter (MCUKF) with the proposed adaptive fuzzy kernel size are reformulated to optimize both rule and antecedent parameters, respectively. In addition to the rule parameters, the proposed membership function (MF) parameters and the level of alpha-cuts are also optimized. Five simulation examples with real-world data sets are given for examination. The simulations show that the introduced SO-IT3FLS and learning algorithm result in better accuracy in contrast to the other kind of fuzzy neural networks and conventional learning techniques. Furthermore, it is verified that the robustness of the proposed learning method against non-Gaussian noise is improved in contrast to the conventional Kalman filter, maximum correntropy Kalman filter and unscented Kalman filter. (C) 2021 Elsevier Inc. All rights reserved.
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