1 Introduction
Automatic assessment of learning assignments is a topic of increasing interest today. A number of approaches have been experimented already in different education domains, including mathematics [1] , physics [2], [3], biology [4] and literature [5], though the majority of solutions reported in the literature have been developed in the area of computer science [6], [7], [8], [9], [10], [11]. It is worth observing that the importance of computer-supported assessment is not to be regarded as strictly limited to the education domain. For instance, there exist use cases where automatic assessment tools have been used, e.g., to implement hiring procedures in software development companies [12], to design intelligent platforms for physical rehabilitation [13], [14], to score sport and art performances [15], [16], etc.