Agent communication and artificial institutions

In this paper we propose an application-independent model for the definition of artificial institutions that can be used to define open multi-agent systems. Such a model of institutional reality makes us able also to define an objective and external semantics of a commitment-based Agent Communication Language (ACL). In particular we propose to regard an ACL as a set of conventions to act on a fragment of institutional reality, defined in the context of an artificial institution. Another contribution of the work presented in this paper is an operational definition of norms, a crucial component of artificial institutions. In fact in open systems interacting agents might not conform to the specifications. We regard norms as event-driven rules that when are fired by events happening in the system create or cancel a set of commitments. An interesting aspect of our proposal is that both the definition of the ACL and the definition of norms are based on the same notion of commitment. Therefore an agent capable of reasoning on commitments can reason on the semantics of communicative acts and on the system of norm

Agent Interaction Semantics by Timed Operating Instructions

Constrasting the standard framework based on agent-to-agent direct communication, in this paper we focus on agent interaction with the environment. In particular, the environment is seen as populated by coordination artifacts, automatising coordination tasks and mediating agent interaction. As a semantic framework for this context we propose operating instructions, which the agent reads and interprets to become aware of the allowed actions and perceptions at a given time, and the MAS infrastructure can exploit to enforce correct agent behaviours and detect wrong ones. This allows us to conceptually handle a number of crucial aspects related to agent interaction, including interaction protocols, timing properties - such as delays and timeouts -, and a notion of contract featuring violation and guarantees. Formally, our framework is based on a process algebra featuring (i) explicit connection between action and its related perceptions, (ii) a time-based branch operator, (iii) violation and guarantee deadlock states, and (iv) association of mental properties to interactions