An automatic marking system for FOL to CF conversions

The FOL to CF system is a web-based interactive system that aims at helping students in learning converting first order logic (FOL) formulas to their clause form (CF). In this paper, we present a system for automatic marking FOL to CF conversion exercises with feedback. First, the system checks a student´s answers in order to spot and recognize errors made. This is done after having analyzed each clause. Second, it automatically marks the answers based on the types of the errors and the structure of the clause. Each error type has a different contribution (weight) in the final mark. The final mark is composed of partial marks concerning different structural elements of a clause. By using the automatic marking system, we can mark tests automatically and also collect information about the learning status of each student. Also, it is able to provide feedback on errors made by students through interacting with them. Experimental results show good agreement between the system and the tutor. Also, questionnaire based evaluation shows satisfaction of the students from using the system.