63results about How to "Reduce distribution variance" patented technology

The invention discloses a fault diagnosis method based on adaptive manifold embedding dynamic distribution alignment. According to the method, the feature distortion of data in an original Euclidean space can be effectively avoided through the automatic calculation of the optimal subspace dimension and the calculation of the streaming kernel of a geodesic line and converted manifold feature representations; a similarity measure A-distance is introduced to define a self-adaptive factor; relative weights of condition distribution and edge distribution of sample data are dynamically adjusted, andtherefore, the distribution difference of source domain and target domain samples can be effectively reduced, the accuracy and effectiveness of rolling bearing fault diagnosis under variable workingconditions can be greatly improved. The method is high in interpretability, is lower in requirements for computer hardware resources, is higher in execution speed, and is excellent in diagnosis precision, algorithm convergence and parameter robustness. The method is especially suitable for multi-scene and multi-fault bearing fault diagnosis under variable working conditions, and can be widely applied to fault diagnosis tasks of complex systems such as machinery, electric power, chemical engineering and aviation under variable working conditions.

The invention discloses a fault diagnosis method for a deep adversarial migration network based on a Wasserstein distance. The distance of the feature distribution of the two fields in the feature space is measured through the wassertein distance, the feature distribution is adapted, the difference between two fields is reduced, field-independent features are learned to train an effective classifier, the classifier is responsible for mapping the field-independent features to a category space to complete a classification task, and the problem of unsupervised transfer learning of vibration datawithout labels in a target domain is solved.

The invention discloses a domain self-adaptive equipment operation inspection system and method. An image acquisition processing module is used for acquiring a to-be-detected inspection image of a power transmission line and preprocessing the image; the to-be-detected inspection image is input into a preset weather condition classification model to identify weather conditions to which the to-be-detected inspection image belongs, and a weather condition classification result is obtained; a corresponding preset domain self-adaptive equipment operation inspection model is selected according to the weather condition classification result; and the to-be-detected inspection image is input into a preset domain self-adaptive equipment operation inspection model to obtain a detection result of theto-be-detected inspection image, wherein the detection result comprises one or a combination of equipment category, working condition and position information of a detection object in the to-be-detected inspection image. According to the invention, the to-be-detected sample of the high-voltage transmission line domain self-adaptive equipment operation detection system is not restricted by sample annotation and regional or weather conditions, and the equipment operation detection result of the target domain in the domain self-adaptive scene has the same detection performance as that of the source domain.

The invention discloses a wind turbine generator fault diagnosis method, which comprises the following steps: according to the vibration signal characteristics of a wind turbine generator gearbox, carrying out variational mode decomposition on signals under different working conditions to obtain a series of intrinsic mode function components, and respectively solving multi-scale permutation entropies of the intrinsic mode function components; combining the multi-scale permutation entropy and the original signal time domain feature into a feature vector, and inputting the feature vector into atransfer learning algorithm; the covariance of a source domain and a target domain being minimized through a linear transformation matrix, the distribution difference of signal data of the source domain and the target domain being reduced through second-order statistics alignment, and then inputting the feature vectors of the aligned signal data of the source domain and the target domain into a support vector machine for fault classification. According to the method, the problem of poor classification effect caused by different distribution of the vibration signal data under different workingconditions can be solved, and the method has higher accuracy in wind turbine generator fault diagnosis under variable working conditions.

The invention discloses an image classification method based on subspace projection and dictionary learning. Firstly, a discrimination dictionary is initialized through a training set sample with a label, and then a class label of a test sample is predicted by using the discrimination dictionary. A test set sample with high reliability is selected and a low dimensional subspace is learned from thetest set sample with false tags and the discriminant dictionary is updated in this low dimensional space. The updated discriminant dictionary is used to reclassify the test set samples, the pseudo-label obtained by this iteration is compared with the pseudo-label obtained by the previous iteration, the samples with the same attribute obtained by the two iterations are called stable samples. If the number of stable samples exceeds eighty percent of the number of samples in the test set after one iteration, the pseudo-label obtained by this iteration is output as the classification result afterthe iteration is over. Compared with the prior art adaptive image classification method, the algorithm of the invention can obtain higher classification accuracy.

The invention discloses a domain adaptive pedestrian re-identification method based on mutual divergence learning. The method comprises the following steps: preparing a pedestrian data set; pre-training the source domain data set, and extracting feature vectors of pictures from the target domain data set; performing density-based clustering on the images of the target domain data set, and taking the number of the cluster as a pseudo label; adding the outliers into a training sample by using an adversarial strategy; mixing the clustered samples and the outliers, sending the mixture into a network, correcting noise of a pseudo tag by adopting mutual divergence learning, inputting a pedestrian image to be queried into a trained pedestrian re-identification model to obtain a pedestrian feature vector to be identified, performing similarity comparison on the pedestrian feature vector to be identified and attribute features in a candidate library, and obtaining a pedestrian re-identification result. According to the invention, the distribution difference between the source domain and the target domain is reduced, the knowledge of the source domain is effectively utilized, and finally, the framework can learn the characteristics with robustness and discrimination.

The invention relates to a domain self-adaption technology in the field of machine learning, and provides a Grassmann manifold domain self-adaption method based on symmetric matrix space subspace learning. In order to reduce the difference between the probability distribution of the source domain data and the target domain data, the method comprises the following steps of firstly establishing mapping from a Grassmann manifold to a symmetric matrix space, then mapping the Grassmann manifold matrix data of the source domain and the target domain to the symmetric matrix space, and constructing asubspace in the symmetric matrix space; subjecting the projection of the original data in the subspace to a mean value similarity criterion; establishing an objective function of the subspace learning, optimizing and solving the objective function to obtain the objective subspace, matching the projection probability distribution of the original data in the objective subspace on the objective subspace, that is, achieving the domain self-adaption of the original data through twice transformation from the Grubman manifold to the symmetric matrix space and then from the symmetric matrix space to the subspace of the symmetric matrix space.

The invention discloses an open set fault diagnosis method for a bearing of a high-speed motor train unit. The open set fault diagnosis method comprises the steps of collecting a vibration signal of the bearing of the high-speed motor train unit in operation through an acceleration sensor; aiming at an open set diagnosis scene of a constant working condition, inputting training data with a label to train a one-dimensional convolutional neural network; inputting labeled source domain data and unlabeled target domain data to train the bilateral weighted adversarial network according to an open set diagnosis scene with working condition changes; establishing an extreme value theoretical model by utilizing the characteristics of the training data or the source domain data, inputting the characteristics of the test sample or the target domain sample into the established extreme value theoretical model, outputting the probability that the test sample or the target domain sample belongs to an unknown fault type, and if the probability is greater than a threshold value, determining that the test sample or the target domain sample belongs to the unknown fault type, and if not, determining that the test sample or the target domain sample belongs to the known fault type. The type of the test sample or the target domain sample is determined according to the label predicted value so as to realize the fault diagnosis of the bearing of the high-speed motor train unit.

The invention discloses an enterprise electricity consumption prediction method. The method comprises the following steps: 1) data acquisition; 2) introducing the maximum mean value difference, and carrying out similarity analysis; 3) modeling a long short-term memory network of transfer learning; and 4) electric quantity prediction: predicting the electric quantity of the target domain enterprise at the future moment by using the improved model in the step 3). The problem of insufficient data volume during electric quantity prediction is effectively solved, the model training time is saved, and the electric quantity prediction precision is improved.

A cross-project defect prediction method based on feature distribution alignment and neighborhood instance selection specifically comprises the following steps: selecting source projects from a software defect data set, combining all the source projects to form a source project set, and selecting a target project; calculating a covariance matrix of the source item set and a covariance matrix of the target item; eliminating the correlation between the features of the source item set, filling the feature correlation of the target item into the source item set, and selecting instances with high similarity with instances in the target item from the source item set data after feature alignment to form a training instance set TS; and training a Logistic model by using the training instance set TS, and performing defect prediction classification on each instance in the target project by using the Logistic model. According to the cross-project software defect prediction method, the selection of the training data required by the model is achieved by adopting the feature distribution alignment method and the neighborhood instance selection method, the difference between projects and instances in the cross-project software defect prediction method is effectively solved, and the defect prediction performance is improved.

The invention belongs to the technical field of tobacco leaf curing process analysis, and particularly relates to an online prediction method for chemical components in the tobacco leaf curing process based on transfer learning and a near infrared spectrum. The method comprises the steps of obtaining a tobacco spectrum in the tobacco leaf curing process; obtaining chemical component values of the tobacco leaves, wherein the chemical component values comprise moisture, starch, protein and total sugar; constructing a prediction model according to the tobacco leaf spectrum and the tobacco leaf curing chemical components; minimizing the difference between a training set tobacco leaf sample and a to-be-predicted feature data set by using a migration component analysis method, and carrying out multiple iterations on the data processed by the migration component analysis method by adopting a partial least square algorithm to train a curing process tobacco leaf chemical component prediction model; and conducting online prediction on the tobacco leaf curing process by using the updated new model, and evaluating a prediction result. The change trend of key chemical components in the tobacco leaf curing process can be predicted, and a basis is provided for accurate adjustment of the tobacco leaf curing process.

The invention discloses a cross-modal retrieval method based on modal specificity and shared feature learning, which comprises the following steps: S1, acquiring a cross-modal retrieval data set, and dividing the cross-modal retrieval data set into a training set and a test set; S2, respectively carrying out feature extraction on the text and the image; S3, extracting modal specific features and modal sharing features; S4, generating a hash code corresponding to the modal sample through a hash network; S5, training the network by combining the loss function of the adversarial auto-encoder network and the loss function of the Hash network; and S6, performing cross-modal retrieval on the samples in the test set by using the network trained in the step S5. According to the method, a Hash network is designed, encoding features of image channels, encoding features of text channels and modal sharing features are projected into a Hamming space, and modeling is performed by using label information, modal specificity and sharing features, so that output Hash codes have better semantic discrimination between modals and in the modals.

The invention provides a crowdsourcing text integration method based on multi-stage transfer learning strategy synthesis. The crowdsourcing text integration method specifically comprises the following steps: 1, constructing a transfer generation type crowdsourcing text integration model TTGCIF; 2, obtaining semantic prototypes of the source domain text data set and the target domain text data set; 3, performing word embedding processing on the semantic prototype; 4, performing data distribution alignment according to the maximum mean value difference; 5, performing semantic prototype transduction model training on the TTGCIF; 6, processing the source domain text data set into a training task set; 7, inputting the training task set into the TTGCIF to carry out field fast adaptation model training; and 8, inputting a part of the target domain text data set into the TTGCIF to carry out model fine tuning training. Through the process, text integration is realized. According to the method, the requirement for data labels in a traditional method can be abandoned, waste of manpower and material resources is reduced, and crowdsourcing text integration in a data scarcity scene is greatly promoted.