System architecture. The system is built upon a rule-based expert system. KB contains the expertise about the application domain in the form of facts and rules. The Reasoner, that is an inference engine, according to the user's requests, input data and available knowledge, decides what are the strategies to follow and the tools to run, and suggest them to the User. The Executor actually runs all the executable processing tools and updates the KB with results of processing, that can be used to make new inferences.
Fiannaca et al. BMC Bioinformatics 2013 14(Suppl 1):S5 doi:10.1186/1471-2105-14-S1-S5