Following Ratinov and Roth ( 2009 ) , we also compare the performance of our system with a system using features based on the Brown clusters of the word types in a document .
design challenges and misconceptions in named entity recognition
Lev Ratinov Dan Roth
These lexicons were gathered from US Census data , Wikipedia category pages , and Wikipedia redirects ( and will be made publicly available upon publication ) . Following Ratinov and Roth ( 2009 ) , we also compare the performance of our system with a system using features based on the Brown clusters of the word types in a document . Since , as seen in section 2.1 , Brown clusters are hierarchical , we use features corresponding to prefixes of the path from the root to the leaf for each word type .
Following @@CITATION , we also compare the performance of our system with a system using features based on the Brown clusters of the word types in a document .