Abstract: The present application provides an audio and video playing system, a playing method and a playing device. The system comprises: a display device; a directional sound output module configured to output a directional sound signal; a tracking element configured to monitor a target visual area and to monitor the target display area on the display screen; and a processor, connected with the directional sound output module and the tracking element respectively, and configured to acquire a first audio and video data to be output in the target display area, display image information of the first audio and video data in the target display area, and output sound information of the first audio and video data to the directional sound output module such that the directional sound output module output a directional sound signal towards the target visual area.

Abstract: The present invention relates to the technical field of fault location of distributed energy resources connected flexible DC distribution network, and disclosed a fault location method, system and application of bipolar short-circuit of two-level VSC-type photovoltaic-connected flexible DC distribution network, wherein, directions of positive currents of DC feeders during fault are used to locate a fault section; a bipolar short-circuit distance measurement model covering interactions and responses of systems is established according to equivalent circuits of transient periods; and fault location is done by obtaining a distance to fault with electric parameters and information of the fault.

Abstract: An efficient, secure and low-communication vertical federated learning method, includes: all participants select part of features of a held data feature set and a small number of samples of the selected features; the participants add noise satisfying differential privacy to part of samples of the selected features, and then send them to other participants together with data indexes of the selected samples; all participants take the received feature data as a label, take each missing feature as a learning task, and train each model with the feature data originally held in the same data index, respectively; all participants predict the data of the other samples with the trained model to complete the missing feature; the participants jointly train a model through horizontal federated learning. The present disclosure can protect data privacy and provide quantitative support for data privacy protection while efficiently training the model with horizontal federated learning.

Abstract: Disclosed is a federated learning method for a k-means clustering algorithm. Horizontal federated learning includes the following steps: 1) initializing K clusters, and distributing, a local sample to a cluster closest to the sample; 2) calculating a new cluster center of the cluster; and 3) if the cluster center changes, then returning to step 1). Vertical federated learning includes the following steps: 1) running, the k-means clustering algorithm locally to obtain T local clusters and intersecting to obtain TL new clusters, or running an AP clustering algorithm to obtain Ti clusters and intersecting to obtain ?i=1LTi new clusters; 2) taking TL (?i=1LTi) new cluster centers as input samples, and initializing the K clusters; 3) distributing each sample to the cluster closest to the sample; 4) calculating a new cluster center of the cluster; and 5) if the cluster center changes, then returning to step 3).

Abstract: Disclosed is a federated learning method for decision tree-oriented horizontal. The method comprises the following steps: all participants searching for a quantile sketch of each feature in a data feature set based on dichotomy; the participants constructing a local histogram for each feature by using locally held data features according to the quantile sketch; adding noise satisfying differential privacy to all local histograms, and sending the local histograms to a coordinator after processing through the secure aggregation method; the coordinator merging the local histograms of each feature into a global histogram, and training a root node of a first decision tree according to the histogram; the coordinator sending information of the node to other participants; and all participants updating the local histograms and repeating the above process for training to obtain the trained decision trees.

Abstract: Provided is a decision tree-oriented vertical federated learning method, which mainly comprises the following steps: 1) all participants sorting local samples for each local feature, and then dividing the sorted samples into different blocks in sequence, each block being called a bucket; 2) for a group of samples corresponding to each feature, a bucket number of each sample under this feature having a certain probability to become other bucket numbers, and selecting an appropriate probability to make this encryption method meet the definition of differential privacy; 3) each participant sending serial numbers of buckets assigned to different samples under different features to the participant who holds a label, and this participant being called a coordinator;4) the coordinator training a decision tree model according to these samples, and no other participants being needed in the training process.

Abstract: The present disclosure provides a detection method of a projector, a projector, and an electronic device. The method includes: obtaining a speckle pattern, the speckle pattern being an image generated by irradiating laser light generated by a light source in the projector onto an object by an optical element; and performing an abnormality detection on the projector according to the speckle pattern.

Abstract: The present disclosure provides a detection method of a projector, a projector, and an electronic device. The method includes: obtaining a speckle pattern, the speckle pattern being an image generated by irradiating laser light generated by a light source in the projector onto an object by an optical element; and performing an abnormality detection on the projector according to the speckle pattern.