Patent ID: 8909643

Claim:
A system for inferring topic evolution and emergence as topics evolve and emerge over time in an evolving discussion comprised of a temporal sequence of a multitude of documents, the system comprising one or more processing units configured for: forming a group of matrices using text in the documents, said group of matrices including a first, document—word matrix X identifying a multitude of words in the documents, a second, document—type matrix W identifying a multitude of topics in the documents, and a third, topic-word matrix H identifying a multitude of words for each of said multitude of topics; and analyzing the temporal sequence of the documents to identify a first group of said multitude of topics as evolving over time from document to document in the evolving discussion and a second group of said multitude of topics as emerging over time in said evolving discussion, including for each of the documents, identifying the words of the first matrix that are in said each document and using the words of the document identified in the first matrix to identify one or more of the topics of the second matrix as one or more topics of said each document, and comparing the identified one or more topics of each of the documents with the identified one or more topics of others of the documents to identify the evolving topics and the emerging topics of the discussion; and wherein the analyzing the temporal sequence of the documents includes: using a first regularizer μ to enforce smooth evolution of the evolving topics; and using a second regularizer Ω to apply a topic bandwidth for early detection of the emerging topics.