Large-Scale Syntactic Processing: Parsing the Web


Scalable syntactic processing will underpin the sophisticated language technology needed for next generation information access. Companies are already using nlp tools to create web-scale question answering and “semantic search” engines. Massive amounts of parsed web data will also allow the automatic creation of semantic knowledge resources on an unprecedented scale. The web is a challenging arena for syntactic parsing, because of its scale and variety of styles, genres, and domains.

The goals of our workshop were to scale and adapt an existing wide-coverage parser to Wikipedia text; improve the efficiency of the parser through various methods of chart pruning; use self-training to improve the efficiency and accuracy of the parser; use the parsed wiki data for an innovative form of bootstrapping to make the parser both more efficient and more accurate; and finally use the parsed web data for improved disambiguation of coordination structures, using a variety of syntactic and semantic knowledge sources.

The focus of the research was the C&C parser (Clark and Curran, 2007c), a state-of-the-art statistical parser based on Combinatory Categorial Grammar (ccg). The parser has been evaluated on a number of standard test sets achieving state-of-the-art accuracies. It has also recently been adapted successfully to the biomedical domain (Rimell and Clark, 2009). The parser is surprisingly efficient, given its detailed output, processing tens of sentences per second. For web-scale text processing, we aimed to make the parser an order of magnitude faster still. The C&C parser is one of only very few parsers currently available which has the potential to produce detailed, accurate analyses at the scale we were considering.

Johns Hopkins University
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