title: Computer-assisted learning using a dialogue system for virtual teacher-student communication.
abstract: Over the past decade, computer-assisted learning in the field of chemistry has given rise to a large number of systems that approach this objective from different viewpoints: static courses aimed at specific concepts, tutorial systems, 2D and 3D virtual environments, and so on. Correct structuring and representation of the knowledge to be taught, the building of a suitable student interface, and the adaptation of the learning process to the knowledge of the student are but a few of the challenges to be faced in the development of efficient computer-assisted learning systems. The present study tackles the use of computerized dialogue systems as a viable alternative for the simulation of teacher-student interaction and proposes an ontology for the characterization of such interaction, employing the object-oriented paradigm in the modeling of both the knowledge to be taught and the actual level of the student. The proposed solution is based on the representation of the knowledge to be taught through a network of multiconnected knowledge frames (chunks), where each chunk may be specialized in more specific frames (prerequisites and subobjectives), contain associated explanations of varying complexity and with a range of explanatory models, and be associated with one or a set of possible questions the student might ask; to this end, a constantly evolving knowledge model is maintained throughout the explanatory process. Based on the proposed model, Java was used to develop and manage an explanatory system that could be used in any type of teaching system based on student-dominated dialogues. Here, the system has been applied to the teaching of chemistry laboratory practice by its integration into the Virtual Chemistry Laboratory (VCL), a system designed by the authors to simulate chemistry techniques in a virtual 3D world.