Knowtator

As a software tool, Knowtator has garnered universal acclaim for its ability to facilitate the manual creation of training and evaluation corpora for a range of biomedical language processing tasks. Integrated with the highly regarded Protégé knowledge representation system, Knowtator serves as a plugin that builds on the strengths of Protégé and its knowledge representation capabilities to further specify annotation schemas.

One of Knowtator's standout features is the simplicity with which users can define complex annotation schemas, including those that have constrained relationships between entity types. This sets the software apart from other annotation tools on the market.

Furthermore, using Protégé ontology to define annotation schemas makes it easy to incorporate domain knowledge for semantic annotation. This makes Knowtator an ideal choice for users who want to incorporate their specific knowledge into the annotation schema.

All in all, Knowtator is a highly recommended tool for creating training and evaluation corpora, and its tight integration with Protégé makes it a seamless experience for users. The ease of defining complex annotation schemas and incorporating domain knowledge for semantic annotation is a major plus that sets Knowtator apart from other similar software.