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119 results about "Recursive computation" patented technology

Penicillin fermentation process failure monitoring method based on recursive kernel principal component analysis

The invention relates to a penicillin fermentation process failure monitoring method based on recursive kernel principal component analysis (RKPCA), which belongs to the technical field of failure monitoring and diagnosis. The method comprises the following steps: acquiring the ventilation rate, stirrer power, substrate feed rate, substrate feed temperature, generated heat quantity, concentrationof dissolved oxygen, pH value and concentration of carbon dioxide; and establishing an initial monitoring model by using the first N numbered standardized samples, updating the model by a RKPCA method, and computing the characteristic vectors to detect and diagnose the failure in the process of continuous annealing, wherein when the T2 statistics and SPE statistics exceed the respective control limit, judging that a failure exists, and otherwise, judging that the whole process is normal. The method mainly solves the problems of data nonlinearity and time variability; and the RKPCA method is used for updating the model by carrying out recursive computation on the characteristic values and characteristic vectors of the training data covariance. The result indicates that the method can greatly reduce the false alarm rate and enhance the failure detection accuracy.
Owner:NORTHEASTERN UNIV

Fault detection method of unmanned aerial vehicle flight control system

The invention relates to a fault detection method of an unmanned aerial vehicle flight control system. Online detection of the fault of the actuator and the sensor of the fixed-ring unmanned aerial vehicle flight control system can be realized by the method. An unmanned aerial vehicle flight control system continuous nonlinear fault model is established on the basis of the unmanned aerial vehiclekinetic equation and the fault type; and then the unmanned aerial vehicle flight control system continuous nonlinear fault model is converted into an unmanned aerial vehicle flight control discrete time-varying fault model with the help of a nonlinear observer, and unmanned aerial vehicle flight control system fault detection is realized by using an equivalent space method. The robustness indicator is designed by aiming at the problem of poor robustness of the conventional equivalent space method under unknown interference so as to enhance the robustness of system fault detection. The extendedKalman filtering equation is utilized in the Krein space to realize recursive computation of the residual evaluation function to reduce the computational burden by aiming at the problem of high computational burden of online fault detection of the conventional equivalent space method. According to the method, quick alarm of the fault of the sensor and the actuator of the unmanned aerial vehicle can be realized so as to provide an effective basis for fault detection of the unmanned aerial vehicle flight control system.
Owner:SHANDONG UNIV OF SCI & TECH

Distributed correlation Kalman filtering-based power system harmonic estimation method

The invention relates to a power system harmonic state estimation method, in particular, a distributed correlation Kalman filtering-based power system harmonic estimation method. The method includes the following steps of: (1) acquiring response signal data z(n) of a power system; (2) establishing a state space model of power system response sampling signals; (3) determining the value of the correlation coefficient zeta ij of neighbor nodes; (4) obtaining a state vector estimation value X^(K) at a time point k based on recursive computation through adopting a distributed correlation Kalman filtering algorithm; and (5) extracting the amplitude and phase of harmonics at the time point k. According to the distributed correlation Kalman filtering-based power system harmonic estimation method provided by the invention, the characteristics of the harmonic state of the power system are fully considered, and therefore, compared with traditional Kalman filtering communication, the distributed correlation Kalman filtering-based power system harmonic estimation method has the advantages of low communication cost, excellent anti-disturbance performance and higher estimation accuracy, and thus, a better data base can be provided for the elimination of harmonic components. The method provided by the invention can be conveniently applied to the harmonic state estimation of the power system.
Owner:HEFEI UNIV OF TECH

Time varying network link packet loss probability estimation method based on Kalman filter

InactiveCN103490955AReact to time-varying properties in real timeReduce mean square errorError preventionData switching networksPacket lossProbability estimation
The invention discloses a time varying network link packet loss probability estimation method based on a Kalman filter. The time varying network link packet loss probability estimation method based on the Kalman filter mainly comprises a training phase and an estimation phase. In the training phase, a source node sends back-to-back detection packets to multiple destination nodes so as to obtain path data, then, prior information of time varying link packet loss probability is estimated according to the path data, and a state transition equation of the Kalman filter is established. In the estimation phase, under the condition that the detection packets do not need to be sent, recursive computation and estimation of the time varying link packet loss probability are completed through a feedback control method according to the state transition equation and the path data obtained from network background flow. Due to the fact that a Kalman filter module is introduced to estimate the link packet loss probability of a time varying network, an obtained link packet loss probability estimated result has a minimum mean square error as well as high estimated accuracy, and the time-variation characteristic of the time varying network link packet loss probability can be reflected in real time.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Near space circular synthetic aperture radar rapid back-direction projection imaging method

The invention discloses a near space circular synthetic aperture radar rapid back-direction projection imaging method. In view of the problem of near space circular synthetic aperture radar rapid imaging, the method replaces a phase error in coherent imaging method with a pixel amplitude error as the evaluation criterion of imaging precision, approximately expands through low order of Green function which is based on chebyshev nodes and lagrange interpolation according to the principle of minimum mean square error, switches the problem of calculation of sub aperture projection to the problem of calculation of limited number of approximate expansion coefficients, and reduces as much as possible the number of expansion coefficients under the condition of meeting the focusing accuracy so that algorithm computational complexity is reduced, and then accomplishes the imaging from coarse focusing to fine focusing by applying recursive computation. Compared with the existing circular SAR back-direction projection imaging method, the near space circular synthetic aperture radar rapid back-direction projection imaging method has the advantages that computing speed is greatly improved, big scene imaging is achieved and imaging accuracy is much higher.
Owner:UNIV OF ELECTRONIC SCI & TECH OF CHINA

Multi-head attention memory network for short text sentiment classification

The invention discloses a multi-head attention memory network for short text sentiment classification. The network comprises a multi-hop memory sub-network, the multi-hop memory sub-network comprises a plurality of independent calculation modules which are connected in sequence, and each independent calculation module comprises a first multi-head attention coding layer, a first linear layer and an output layer which are connected in sequence. The input of each multi-head attention coding layer in the multi-hop memory sub-network comprises original memory and historical information memory, and the multi-head attention memory network learns more complex and abstract nonlinear features contained in a text through stacking conversion of independent calculation modules with enough hop counts; the emotion semantic structure in the text is effectively coded. Furthermore, the original memory of the input multi-hop memory sub-network is fully interacted by the recursive calculation process of the multi-head attention coding layer, so that the remote dependency relationship between the text features is modeled with more components, and the context emotion semantic relationship with higher level is mined, thereby improving the classification performance of the model.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
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