Protocols represent the allowed interactions among communicating agents. Protocols are essential in applications such as electronic commerce where it is necessary to constrain the behaviors of autonomous agents. Traditional approaches, which model protocols in terms of action sequences, limit the flexibility of the agents in executing the protocols. By contrast, we develop an approach for specifying protocols in which we capture the content of the actions through agents' commitments to one another. We forrealize commitments in a variant of the event calculus. We provide operations and reasoning rules to capture the evolution of commitments through the agents' actions. Using these rules in addition to the basic event calculus axioms enables agents to reason about their actions explicitly to flexibly accommodate the exceptions and opportunities that arise at run time. This reasoning is implemented using an event calculus planner that helps us determine flexible execution paths that respect the protocol specifications.

We present a logic-based formalism for modeling of dialogues between intelligent and autonomous software agents, building on a theory of abstract dialogue games which we present. The formalism enables representation of complex dialogues as sequences of moves in a combination of dialogue games, and allows dialogues to be embedded inside one another. The formalism is computational and its modular nature enables dierent types of dialogues to be represented.

Abstract. We develop an approach in which we model communication protocols via commitment machines. Commitment machines supply a content to protocol states and actions in terms of the social commitments of the participants. The content can be reasoned about by the agents thereby enabling flexible execution of the given protocol. We provide reasoning rules to capture the evolution of commitments through the agents ’ actions. Because of its representation of content and its operational rules, a commitment machine effectively encodes a systematically enhanced version of the original protocol, which allows the original sequences of actions as well as other legal moves to accommodate exceptions and opportunities. We show how a commitment machine can be compiled into a finite state machine for efficient execution, and prove soundness and completeness of our compilation procedure. 1

Designers of agent communications protocols are increasingly using formal dialogue games, adopted from argumentation theory, as the basis for structured agent interactions. We propose a set of desiderata for such protocols, drawing on recent research in agent interaction, on recent criteria for assessment of automated auction mechanisms and on elements of argumentation theory and political science. We then assess several recent dialogue game protocols against our desiderata, revealing that each protocol has serious weaknesses. For comparison, we also assess the FIPA Agent Communications Language (ACL), thereby showing FIPA ACL to have limited applicability to dialogues not involving purchase negotiations. We conclude with a suggested checklist for designers of dialogue game protocols for agent interactions.

The Kanger-Lindahl theory of normative positions attempts to use a combination of deontic logic (the logic of obligation and permission) and a logic of action/agency to give a formal account of obligations, duties, rights, and other complex normative concepts. This paper presents a generalisation and further development of this theory, together with methods for its automation and application to practical examples. The resulting theory is intended to be applied in the representation and analysis of laws, regulations, and contracts, in the specification of aspects of computer systems, in multi-agent systems, and as a contribution to the formal theory of organisations. Particular attention is paid to representations at varying levels of detail and the relationships that hold between them. The last part presents Norman-G, an automated support system intended to facilitate application of the theory to the analysis of practical problems, with a small example to illustrate its use.

This survey introduces existing approaches to agent communications languages (ACLs) and particularly, conversation policies (CPs) which can be viewed as general constraints on the sequence of semantically coherent messages leading to a goal. Then limitations of these CPs are discussed in detail, particularly limitations on flexibility and specification. Finally, ACLs are viewed from the dialectic point of view, and some approaches are introduced in this context: some focusing on commitment-based protocols and others on dialogue-game based protocols.

Abstract. Commitments among agents are widely recognized as an important basis for organizing interactions in multiagent systems. We develop an approach for formally representing and reasoning about commitments in the event calculus. We apply and evaluate this approach in the context of protocols, which represent the interactions allowed among communicating agents. Protocols are essential in applications such as electronic commerce where it is necessary to constrain the behaviors of autonomous agents. Traditional approaches, which model protocols merely in terms of action sequences, limit the flexibility of the agents in executing the protocols. By contrast, by formally representing commitments, we can specify the content of the protocols through the agents ’ commitments to one another. In representing commitments in the event calculus, we formalize commitment operations and domain-independent reasoning rules as axioms to capture the evolution of commitments. We also provide a means to specify protocol-specific axioms through the agents ’ actions. These axioms enable agents to reason about their actions explicitly to flexibly accommodate the exceptions and opportunities that may arise at run time. This reasoning is implemented using an event calculus planner that helps determine flexible execution paths that respect the given protocol specifications.

This paper studies argumentation-based dialogues between agents. It defines a set of locutions by which agents can trade arguments, a set of agent attitudes which relate what arguments an agent can build and what locutions it can make, and a set of protocols by which dialogues can be carried out. The paper then considers some properties of dialogues under the protocols, in particular termination, dialogue outcomes, and complexity, and shows how these relate to the agent attitudes.

this article is that protocols are meant to achieve certain tasks, that is, they have a goal. Starting from this observation, the authors identify the landmarks or the state of affairs that must be brought about during the execution of a protocol in order to achieve its goal. Therefore the important aspect of protocols are these landmarks rather than the communicative acts needed to achieve the landmarks. Kumar and his colleagues show that families of conversation protocols can be expressed formally as partially ordered landmarks where each landmark is characterized by propositions that are true in the state represented by that landmark. In this context, they treat conversation protocols as joint action expressions and apply the joint intention theory to protocols and their compositions. Finally, they give a formal semantics to group communicative acts and use it to handle group communication in a formal treatment of protocols

Abstract. In this paper we propose an operational method for the definition of the semantics of Agent Communication Languages based on the notion of social commitment. Our proposal is suitable for open interaction frameworks where agents, designed by independent constructors, dynamically enter and leave different interaction systems. In this type of environments it is crucial to define a standard and commonly accepted semantics for the exchanged messages. We give an operational specification of commitment and introduce temporal propositions for the representation of the contents of commitments within an object-oriented paradigm. Then we use operations on commitments to define the meaning of a set of communicative acts that is complete with respect to Searle’s taxonomy of illocutionary acts, and give an example of the use of communicative acts in an interaction protocol. 1