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318 results about "Nonlinear system" patented technology

In mathematics and science, a nonlinear system is a system in which the change of the output is not proportional to the change of the input. Nonlinear problems are of interest to engineers, biologists, physicists, mathematicians, and many other scientists because most systems are inherently nonlinear in nature. Nonlinear dynamical systems, describing changes in variables over time, may appear chaotic, unpredictable, or counterintuitive, contrasting with much simpler linear systems.

Neural network deep learning-based cloth defect detection method

The invention relates to a neural network deep learning-based cloth defect detection method. The method includes the following steps that: (1) high-speed line scanning imaging is performed; (2) an improved BP neural network cloth defect detection algorithm is adopted to accurately detect cloth defects; and (3) a convolutional neural network deep learning-based cloth defect classification algorithm is adopted to automatically select characteristic information of defect diversity, and non-linear and systematic processing and classification are performed. According to the method of the invention, algorithms such as image correction, splicing and de-noising are realized in an imaging system through a GPU, so that high-speed and high-quality image acquisition can be realized; the improved BP neural network cloth defect detection algorithm is adopted to detect and eliminate interference factors such as dust, dirt, cotton balls and folds; and the convolutional neural network deep learning-based cloth defect classification algorithm is adopted to monitor various kinds of detects in real time, and the classification algorithm can automatically select the characteristic information of defect diversity and carry out non-linear and systematic processing and classification.
Owner:GUANGDONG UNIV OF TECH

Lake and reservoir algal bloom predicating method based on multielement nonstationary time series analysis and neural network and support vector machine compensation

The invention discloses a lake and reservoir algal bloom predicating method based on multielement nonstationary time series analysis and neural network and support vector machine compensation, and belongs to the technical field of water quality monitoring. The method comprises the steps of characteristic factor nonstationary time series modeling, error influence factor kernel principal component analysis, neural network error modeling according to the situation of large sample data, support vector machine error modeling according to the situation of small sample data, final error compensation and predicating result obtaining. The problems that existing algal bloom predication precision is not high, and predication is hard to carry out according to the small sample data are solved, the description of the algal bloom forming process corresponds to reality better, and the result of algal bloom modeling predication is more accurate. The advantage compensation of a time series analysis method suitable for linear system modeling and a statistical learning method suitable for nonlinear system modeling is achieved, and the algal bloom predication accuracy is improved.
Owner:BEIJING TECHNOLOGY AND BUSINESS UNIVERSITY

Amplifier digital pre-distortion device and method based on dynamic fuzzy neural network

The invention discloses an amplifier digital pre-distortion device based on a dynamic fuzzy neural network. The amplifier digital pre-distortion device comprises a digital pre-distortion device, a digital analog converter, a broadband quadrature modulator, a power amplifier, an attenuation coupler, a broadband quadrature demodulator, an analog digital converter and a pre-distortion device training module. Dynamic fuzzy neural network pre-distortion processing is conducted on an inputted digital baseband signal through the digital pre-distortion device, coupling, quadrature demodulation and analog digital conversion are conducted on an analog baseband signal outputted by the power amplifier through the attenuation coupler, the broadband quadrature demodulator, the analog digital converter respectively, and then an outputted digital baseband signal is generated. The inputted digital baseband signal and the outputted digital baseband signal are synchronously inputted into the pre-distortion device training module, and the pre-distortion device training module obtains a dynamic fuzzy neural network module parameter after carrying out parameter training through an online self-organized learning algorithm and sends the dynamic fuzzy neural network module parameter to the digital pre-distortion device. The invention further provides an amplifier digital pre-distortion method. By means of the amplifier digital pre-distortion device and method, the advantages of a fuzzy system and the advantages of a neural network are combined, dynamic adjustment can be achieved according to the complexity of a non-linear system, implementation is easy, and the non-linear characteristic and the memory effect of the power amplifier can be well compensated for.
Owner:SOUTHEAST UNIV

Active disturbance control method of flexible direct current power transmission system

The invention relates to an active disturbance control method of a flexible direct current power transmission system. The method adopts the technical scheme that the method comprises the following steps that a rectifier controller is arranged at the head end of a direct current power transmission line of the flexible direct current power transmission system to carry out the constant direct current voltage control on a rectifier at the alternating current system side, an inverter controller is arranged at the tail end of the direct current power transmission line to carry out the constant alternating current voltage control on an inverter, and a double-closed loop type vector control strategy is adopted for the constant alternating current voltage control of the inverter, wherein an outer loop of the voltage is controlled by an active disturbance controller, an inner loop is controlled by current decoupling, and the direction of bus voltage at the inverter alternating current side is fixed to the direction of an axis d. The method has the advantages that the overshoot of the bus voltage at the passive network alternating current side is reduced when the flexible direct current power transmission system starts to respond, the precision and the stability of the alternating current voltage control are improved, the inside and outside total disturbance of the flexible direct current power transmission system can be evaluated in a real-time way, the feedforward compensation can be timely carried out, the disturbance control capability of the flexible direct current power transmission system is improved, and the control requirements of a non-linear system can be met.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)

Pavement peak-value attachment coefficient estimating method on basis of UKF (unscented kalman filter) and corrected Dugoff tire model

The invention discloses a pavement peak-value attachment coefficient estimating method on the basis of a UKF (unscented kalman filter) and a corrected Dugoff tire model. The method is characterized by comprising the following steps: collecting each sensor signal of a vehicle in real time, estimating a slip rate and a slip angle of each wheel by utilizing a longitudinal kinetic equation and a geometric coordinate relation of the model; and transmitting the estimated slip rate, vertical force, the slip angle and the like to a UKF coefficient calculation module based on the corrected Dugoff model to obtain a coefficient vector of a nonlinear system, and transmitting the vector and real-time estimated longitudinal force to a UKF pavement peak-value attachment coefficient estimation module to solve a peak-value attachment coefficient. A vehicle state observation system is used for collecting the signals in real time, so that the real-time property of the calculation is guaranteed, and the estimation accuracy on pavement situations which are not fitted is high. By utilizing the corrected Dugoff tire model and a UKF theory, the solving process is simple, the number of operation is small, the rapidness in operation is realized, and the convergence time is short. The method is good in robustness, capable of well recognizing the pavement situations of each wheel and suitable for being used for estimating the pavement peak-value attachment coefficient in real time.
Owner:TSINGHUA UNIV
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