It is envisioned that the future electric grid will be underpinned by a vast number of smart inverters linking renewables at the grid edge. These inverters' dynamics are typically characterized as impedances, whic...
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It is envisioned that the future electric grid will be underpinned by a vast number of smart inverters linking renewables at the grid edge. These inverters' dynamics are typically characterized as impedances, which are crucial for ensuring grid stability and resiliency. However, the physical implementation of these inverters may vary widely and may be kept confidential. Existing analytical impedance models require a complete and precise understanding of system parameters. They can hardly capture the complete electrical behavior when the inverters are performing complex functions. Online impedance measurements for many inverters across multiple operating points are impractical. To address these issues, we present the InvNet, a machine learning framework capable of characterizing inverter impedance patterns across a wide operation range, even with limited impedance data. Leveraging transfer learning, the InvNet can extrapolate from physics-based models to real-world ones and from one inverter to another with the same control framework but different control parameters with very limited data. This framework demonstrates machine learning as a powerful tool for modeling and analyzing black-box characteristics of grid-tied inverter systems that cannot be accurately described by traditional analytical methods, such as inverters under model-predictive control. Comprehensive evaluations were conducted to verify the effectiveness of the InvNet.
Neural networks are capable function approximators for data, but their lack of interpretability poses challenges. Physical-informed Polynomial Neural Ordinary Differential Equations (PIPNODEs) are proposed. They combi...
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To solve the problems such as large size, dense text area and various handwriting styles, an automatic data extraction technology based on DB and CRNN algorithms is proposed, which mainly includes four modules: image ...
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As an effective non-destructive technology, infrared thermography is often used to detect inner defects in composites. However, non-homogeneous background in the thermal images reduces image quality inevitably. A sque...
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Bridging the gap between physics-based modeling and data-driven machine learning promises to reduce the amount of training data required and to improve explainability in predictive maintenance applications. For a smal...
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ISBN:
(纸本)9798350315684
Bridging the gap between physics-based modeling and data-driven machine learning promises to reduce the amount of training data required and to improve explainability in predictive maintenance applications. For a small fleet of industrial forklift trucks, we develop a physically inspired framework for predicting remaining useful life (RUL) for selected components by integrating physically motivated feature extraction, degradation modelling and machine learning. The discussed approach is promising for situations of limited data availability or large data heterogeneity, which often occurs in fleets of customized vehicles optimized for particular tasks.
This article focuses on fuzzy structural adaptive optimal control issue of discrete-time nonlinear complex networks (CNs) via adopting the reinforcement learning (RL) and Takagi-Sugeno fuzzy modeling approaches, where...
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This article focuses on fuzzy structural adaptive optimal control issue of discrete-time nonlinear complex networks (CNs) via adopting the reinforcement learning (RL) and Takagi-Sugeno fuzzy modeling approaches, where the control gains are subjected to structured constraints. In accordance with the Bellman optimality theory, the modified fuzzy coupled algebraic Riccati equations (CAREs) are constructed for discrete-time fuzzy CNs, while the modified fuzzy CAREs are difficult to solve directly through mathematical approaches. Then, a model-based offline learning iteration algorithm is developed to solve the modified fuzzy CAREs, where the network dynamics information is needed. Moreover, a novel data-driven off-policy RL algorithm is given to compute the modified fuzzy CAREs, and the structural optimal solutions can be obtained directly by using the collected state and input data in the absence of the network dynamics information. Furthermore, the convergence proofs of the presented learning algorithms are provided. In the end, the validity and practicability of the theoretical results are explicated via two numerical simulations.
The remaining useful life (RUL) prediction and state of health (SOH) assessment of lithium-ion batteries are the key technologies for achieving equipment prediction and health management (PHM). Accurate RUL prediction...
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This letter provides, to the best of our knowledge, a first analysis of how biologically plausible spiking neural networks (SNNs) equipped with spike-timing-dependent plasticity (STDP) can learn to detect people on th...
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This letter provides, to the best of our knowledge, a first analysis of how biologically plausible spiking neural networks (SNNs) equipped with spike-timing-dependent plasticity (STDP) can learn to detect people on the fly from nonindependent and identically distributed (non-i.i.d) streams of retina-inspired, event camera data. Our system works as follows. First, a short sequence of event data, capturing a walking human from a flying drone, is forwarded in its natural order to an SNN-STDP system, which also receives teacher spiking signals from the neural activity readout block. Then, when the end of the learning sequence is reached, the learned system is assessed on testing sequences. In addition, we also present a new interpretation of anti-Hebbian plasticity as an overfitting control mechanism and provide experimental demonstrations of our findings. This work contributes to the study of attention-based development and perception in bioinspired systems.
The data-driven method for security monitoring is promising for power system voltage stability estimation, whereas the reliability of such method is greatly affected due to the generalizability weakened by operational...
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The data-driven method for security monitoring is promising for power system voltage stability estimation, whereas the reliability of such method is greatly affected due to the generalizability weakened by operational variability. In this article, a mechanism knowledge enhanced machine learning method for load margin estimation is established by integrating power system mechanism into intelligent neural network (NN) model. Firstly, the correlation between the load power factor and load margin explored fromcurve P-V were analyzed, from which the mechanism knowledge of voltage stability is extracted. Then, the mathematical logical representation of mechanism knowledge is given, which was further integrated into the loss function of the NN model. The proposed enhanced model constrains the NN model to provide mechanistically consistent results, as well as helps achieve an excellent generalizability performance. The effectiveness of the proposed method is verified by numerical simulations using the ieee 39-bus test system and the ieee 145-bus test system, the results of which shows that the generalization ability of the enhanced NN is significantly improved with the proposed method, thus the accuracy, reliability and robustness of the load margin estimation are greatly enhanced.
Accurate altitude information is essential for achieving safe flight, especially during take-off and landing. The Kalman filter (KF) is an optimal state estimation method that can be utilized for flight altitude estim...
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