Data-driven fault diagnosis is increasingly prevalent in recent years for complex systems, but still suffers from two practical difficulties: one is the lack of enough historical examples of fault equipment and the ot...
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Data-driven fault diagnosis is increasingly prevalent in recent years for complex systems, but still suffers from two practical difficulties: one is the lack of enough historical examples of fault equipment and the other is the absence of personalized characteristics of the equipment to be diagnosed. This paper proposes an adaptive ensemble fault diagnosis method to resolve these two difficulties. The proposed method first extracts fault and normal patterns by constructing hidden Markov models (HMMs), respectively, from historical fault and normal examples. Then fault diagnosis decisions made by the supervised and unsupervised methods are intrinsically integrated through the hidden states identified by HMMs to overcome the difficulty of lacking enough historical fault examples. Finally, a learning process is designed and embedded in the proposed method to describe the impacts of personalized characteristics of the equipment on its fault diagnosis. Theoretical and experimental results both verify the effectiveness of the proposed method.
The economic dispatch problem is investigated in this paper for a class of smart grids subject to unknown communication uncertainties. Compared with existing works related to economic dispatch where the dispatch algor...
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The economic dispatch problem is investigated in this paper for a class of smart grids subject to unknown communication uncertainties. Compared with existing works related to economic dispatch where the dispatch algorithms are carried out by a centralized controller, a new kind of distributed dispatch algorithms are developed to achieve optimal dispatch of electric power by appropriately sharing the load among different generating units while guaranteeing consensus among incremental costs. An adaptive weight-adjustment technique is suggested that enables the dispatch algorithms to choose the communication weights among neighboring generating units which yield consensus of incremental costs under both cases with or without capacity limitations. The achievement of such a consensus leads to optimal dispatch of electronic power and secures the system performance against unknown communication uncertainties. Meanwhile, it is proved that the power demand and supply of the considered smart grids will be kept in a balanced state during the dispatch process. The interesting issue of how to assign the power outputs among generating units to balance the power demand and supply of the considered smart grids is also addressed. Finally, the numerical results of several case studies have been provided to verify the effectiveness of the proposed algorithms.
In order to solve the drawbacks of the traditional message push mechanism in terms of diversity, power consumption, traffic consumption, and message real-time performance, an adaptive scheduling algorithm was designed...
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In order to solve the drawbacks of the traditional message push mechanism in terms of diversity, power consumption, traffic consumption, and message real-time performance, an adaptive scheduling algorithm was designed. Based on the algorithm, an adaptive message push strategy that can dynamically allocate message push mode for the terminal was proposed. The experimental results showed that this strategy could reduce the power consumption of mobile terminals and save network traffic while adapting to the diversity of terminals. Therefore, it can ensure the real-time performance of messages.
The interior penalty methods using C^0 Lagrange elements(C^0 IPG) developed in the recent decade for the fourth order problems are an interesting topic at present. In this paper, we discuss the adaptive proporty of C^...
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The interior penalty methods using C^0 Lagrange elements(C^0 IPG) developed in the recent decade for the fourth order problems are an interesting topic at present. In this paper, we discuss the adaptive proporty of C^0 IPG method for the Helmholtz transmission eigenvalue problem. We give the a posteriori error indicators for primal and dual eigenfunctions, and prove their reliability and efficiency. We also give the a posteriori error indicator for eigenvalues and design a C^0 IPG adaptive algorithm. Numerical experiments show that this algorithm is efficient and can get the optimal convergence rate.
In this research paper, adaptive filtering techniques are used to improve performance of the wave iterative method. This method is used for the modeling and the study of the planar microwave electronic circuits which ...
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In this research paper, adaptive filtering techniques are used to improve performance of the wave iterative method. This method is used for the modeling and the study of the planar microwave electronic circuits which are the most used today in the new technologies of radio frequency communication. In order to improve the convergence speed of the wave iterative method, we use the recursive least square algorithm and the stabilized fast transversal filter. A significant gain in computation time is obtained with these new techniques with a good accuracy in the found results.
In this paper, an approach called real-code population-based incremental learning hybridised with adaptive differential evolution (RPBILADE) is proposed for solving many-objective automotive floor-frame optimisation p...
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In this paper, an approach called real-code population-based incremental learning hybridised with adaptive differential evolution (RPBILADE) is proposed for solving many-objective automotive floor-frame optimisation problems. adaptive strategies are developed and integrated into the algorithm. The purpose of these strategies is to select suitable control parameters for each stage of an optimisation run, in order to improve the search performance and consistency of the algorithm. The automotive floor-frame structures are considered as frame structures that can be analysed with finite element analysis. The design variables of the problems include topology, shape, and size. Ten optimisation runs using various optimisers are carried out on two many-objective automotive floor-frame optimisation problems. Twelve additional benchmark tests against all competitors are also performed to demonstrate the search performance of the proposed algorithm. RPBILADE provided better results than other recent optimisers for both the automotive floor-frame optimisation and benchmark problems.
Purpose This paper aims to propose an adaptive unstructured finite volume procedure for efficient prediction of propellant feedline dynamics in fluid network. Design/methodology/approach The adaptive strategy is based...
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Purpose This paper aims to propose an adaptive unstructured finite volume procedure for efficient prediction of propellant feedline dynamics in fluid network. Design/methodology/approach The adaptive strategy is based on feedback control of errors defined by changes in key variables in two subsequent time steps. Findings As an evaluation of the proposed approach, two feedline dynamics problems are formulated and solved. First problem involves prediction of pressure surges in a pipeline that has entrapped air and the second is a conjugate heat transfer problem involving prediction of chill down of cryogenic transfer line. Numerical predictions with the adaptive strategy are compared with available experimental data and are found to be in good agreement. The adaptive strategy is found to be efficient and robust for predicting feedline dynamics in flow network at reduced CPU time. Originality/value This study uses an adaptive reduced-order network modeling approach for fluid network.
We present a numerical method which exploits the biorthogonal interpolating wavelet family, and second-generation wavelets, to solve initial-boundary value problems on finite domains. Our predictor-corrector algorithm...
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We present a numerical method which exploits the biorthogonal interpolating wavelet family, and second-generation wavelets, to solve initial-boundary value problems on finite domains. Our predictor-corrector algorithm constructs a dynamically adaptive computational grid with significant data compression, and provides explicit error control. Error estimates are provided for the wavelet representation of functions, their derivatives, and the nonlinear product of functions. The method is verified on traditional nonlinear problems such as Burgers' equation and the Sod shock tube. Numerical analysis shows polynomial convergence with negligible global energy dissipation.
In traditional sensorless control of the interior permanent magnet synchronous motors (IPMSMs) for medium and high speed domains, a control strategy based on a sliding-mode observer (SMO) and phase-locked loop (PLL) i...
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In traditional sensorless control of the interior permanent magnet synchronous motors (IPMSMs) for medium and high speed domains, a control strategy based on a sliding-mode observer (SMO) and phase-locked loop (PLL) is widely applied. A new strategy for IPMSM sensorless control based on an adaptive super-twisting sliding-mode observer and improved phase-locked loop is proposed in this paper. A super-twisting sliding-mode observer (STO) can eliminate the chattering problem without low-pass filters (LPFs), which is an effective method to obtain the estimated back electromotive forces (EMFs). However, the constant sliding-mode gains in STO may cause instability in the high speed domain and chattering in the low speed domain. The speed-related adaptive gains are proposed to achieve the accurate estimation of the observer in wide speed range and the corresponding stability is proved. When the speed of IPMSM is reversed, the traditional PLL will lose its accuracy, resulting in a position estimation error of 180 degrees. The improved PLL based on a simple strategy for signal reconstruction of back EMF is proposed to ensure that the motor can realize the direction switching of speed stably. The proposed strategy is verified by experimental testing with a 60-kW IPMSM sensorless drive.
Enhancing Synthetic Aperture Radar (SAR) images for sharp and detailed images through super-resolution (SR) is of great significance in many remote sensing applications. Due to the inherent resolution limitations and ...
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Enhancing Synthetic Aperture Radar (SAR) images for sharp and detailed images through super-resolution (SR) is of great significance in many remote sensing applications. Due to the inherent resolution limitations and the cost incurred for further development of sensor devices, image enhancements through image processing techniques have become more popular. However, in these techniques, the soft edges present in the images are not reconstructed completely, thereby marring the clarity of the generated image. This paper presents a method to restore more details in the image by adaptively adjusting the measurement noise covariance and process noise covariance into the intensity estimation framework for SAR image super-resolution. For this, an adaptive Importance Sampling Unscented Kalman Filter (ISUKF) framework is implemented using the covariance matching technique. Experimental results indicate that the super-resolution using ISUKF framework performs better, regarding denoising and feature preservation, when accounted for the measurement and process noise covariance. It also outperforms the other recent and standard SR techniques covered in the literature.
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