Method and apparatus for event extraction and extraction model training, device and medium

A method for an extraction model, comprising:

• determining an initial model;
• training the initial model with a plurality of training samples to obtain the extraction model;
• processing an object text to determine event information of the object text by using the extraction model, wherein the event information comprises an event element, and an event type and a role corresponding to the event element;
• and the extraction model comprises a classification layer, an output layer, and an event extraction layer, processing of the object text by using the preset extraction model, comprising:
• determining a token attribute of a token in the object text by the classification layer, wherein the token attribute comprises whether the token is a start token of the event element, and whether the token is an end token of the event element;
• determining the event element according to the token attribute of the token and determining the event type and the role corresponding to the event element, by the tout layer;
• and
• determining a type probability of each event type by the event extraction layer, wherein the type probability of the event type represents a correlation between the object text and the event type,
• the determining of the token attribute of the token in the object text comprises:
• determining an initial probability that the token in the object text is the start token of the event element of one event type and one role;
• determining, according to the initial probability and the type probability of the event type, whether the token is the start token of the event element of the one event type and the one role;
• determining an initial probability that the token in the object text is the end token of the event element of one other event type and one other role;
• and
• determining, according to the initial probability and the type probability of the event type, whether the token is the end token of the event element of the one other event type and the one other role.