Knowtator: A Protégé plug-in for annotated corpus construction

A general-purpose text annotation tool called Knowtator is introduced. Knowtator facilitates the manual creation of annotated corpora that can be used for evaluating or training a variety of natural language processing systems. Building on the strengths of the widely used Protégé knowledge representation system, Knowtator has been developed as a Protégé plug-in that leverages Protégé’s knowledge representation capabilities to specify annotation schemas. Knowtator’s unique advantage over other annotation tools is the ease with which complex annotation schemas (e.g. schemas which have constrained relationships between annotation types) can be defined and incorporated into use. Knowtator is available under the Mozilla Public License 1.1 at http://bionlp.sourceforge.net/Knowtator.