Recent Advances in Computational Linguistics

ive summarization approaches use information extraction, ontological information, information fusion, and compression. Automatically generated abstracts (abstractive summaries) moves the summarization field from the use of purely extractive methods to the generation of abstracts that contain sentences not found in any of the input documents and can synthesize information across sources. An abstract contains at least some sentences (or phrases) that do not exist in the original document. Of course, true abstraction involves taking the process one step further. Abstraction involves recognizing that a set of extracted passages together constitute something new, something that is not explicitly mentioned in the source, and then replacing them in the summary with the new concepts. The requirement that the new material not be in the text explicitly means that the system must have access to external information of some kind, such as an ontology or a knowledge base, and be able to perform combinatory