Agent to Agent Talk: “Nobody There?” Supporting Agents Linguistic Communication

World-Wide Web technologies and the vision of Semantic Web have pushed for adaptive SW applications to scale up information technologies to the Web, where information is organized following different underlying knowledge and/or presentation models. Interoperability among heterogeneous intelligent agents has become an important research topic in the context of distributed information systems. Communication among heterogeneous agents involves several dimensions. "Ontological commitment" on a shared knowledge model cannot be assumed as a default. To overcome this problem, we will describe in this article a communication model that bases on the use of natural language. We will argue on main topics involved in using natural language to achieve semantic agreement in agents communication. The model foresees a strong separation among terms and concepts, this difference being often undervalued in the literature, where terms play the ambiguous role of both concept labels and of communication lexicon. For agents communicating through the language, lexical information embodies instead the possibility to "express" the underlying conceptualizations thus agreeing to a shared representation. We will examine in details the different layers involved in agents communication and we will focus on a the different roles played by each element. A novel agent architecture able to tackle with possible linguistic ambiguities by focusing on the conversational level will be deeply described. Three different agent typologies will be presented: Resource agents, embodying the target knowledge, Service agents, providing basic skills to support complex activities and control agents, supplying the structural knowledge of the task, with coordination and control capabilities. NL communication is supported by two dedicated Service apnts: a Mediator, that will handle conceptual mismatches arising during coninumication, and a Translator, dealing with lexical misalignments due to different languages/idioms.