Implicit commitments through protocol-level semantics

Artificial Intelligence, 1999

2005

Message semantics are traditionally defined in terms of mental states, which is a trend that is criticized for assuming the sincerity and cooperativeness of agents. To circumvent these limitations, several proposals have been put forth to define the semantics of messages using social commitments.

Semantics and Linguistic Theory, 2016

When saying something in a conversation, an agent publicly commits to some interpretation of what she said, which others might dispute. But how does making a commitment affects the commitments of others? We provide an answer to this question for the case of acknowledgments. Commitment semantics poses a dilemma for acknowledgments: either the semantics is strong, entailing that agent i's committing to ϕ entails other agents commit to i's committing to ϕ. This makes acknowledgments vacuous. Or further acknowledgments are required to produce commitments about others' commitments, but then grounding seems never achievable in finite time. Building on Venant & Asher (2015) we provide a model of these strong and weak semantics where we show how the two are linked via a semantics for inductive, synchronous acknowledgments.

Proceedings of the fourth international joint conference on Autonomous agents and multiagent systems - AAMAS '05, 2005

In this paper, we arrange FIPA's ACL performatives to form a subsumption lattice (ontology) and apply a theory of social commitments to achieve a simplified and observable model of agent behaviour. Using this model, it is straight forward to model agents' social commitments (obligations) based solely on observation of messages passed between the agents (such observation is supported by our agent infrastructure system). Furthermore, owing to the performatives being in a subsumption lattice, it is relatively easy for an observer to infer social commitment relationships even if the observer does not understand the details of messages or even the exact performatives used (so long as the observer has access to the performatives ontology).

Proceedings of the second international joint conference on Autonomous agents and multiagent systems - AAMAS '03, 2003

We propose a method for the definition of interaction protocols to be used in open multiagent systems. Starting from the assumption that language is the fundamental component of every interaction, we first propose a semantics for Agent Communication Languages based on the notion of social commitment, and then use it to define the meaning of a set of basic communicative acts. Second, we propose a verifiable and application-independent method for the definition of interaction protocols, whose main component is the specification of an interaction diagram specifying which actions may be performed by agents under given conditions. Interaction protocols fully rely on the application-independent meaning of communicative acts. We also propose a set of soundness conditions that can be used to verify whether a protocol is reasonable. Finally, our approach is exemplified by the definition of an interaction protocol for English auctions.

Journal of Information Engineering and Applications, 2015

In spite of the fact that modeling and verification of the Multi-Agent Systems (MASs) have been since long under study, there are several related challenges that should still be addressed. In effect, several frameworks have been established for modeling and verifying the MASs with regard to communicative commitments. A bulky volume of research has been conducted for defining semantics of these systems. Though, formal verification of these systems is still unresolved research problem. Within this context, this paper presents the CTL com that reforms the CTLC, i.e., the temporal logic of the commitments, so as to enable reasoning about the commitments and fulfillment. Moreover, the paper introduces a fully-automated method for verification of the logic by means of trimming down the problem of a model that checks the CTLcom to a problem of a model that checks the GCTL*, which is a generalized version of the CTL* with action formulae. By so doing, we take advantage of the CWB-NC automatabased model checker as a tool for verification. Lastly, this paper presents a case study drawn from the business field, that is, the NetBill protocol, illustrates its implementation, and discusses the associated experimental results in order to illustrate the efficiency and effectiveness of the suggested technique.

Applied Artificial Intelligence, 2004

2004

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.

Journal of Software, 2006

Our goal is to extend agent communication languages for persuasion dialogues. We distinguish action commitments from propositional commitments, because both limit future moves, but an action commitment is fulfilled when the hearer believes that the action is performed, whereas a propositional commitment is fulfilled only when the hearer concedes to the proposition -where concessions are the absence of a belief to the contrary, and prevent further challenges. Using a common model for both kind of commitments and a role-based semantics of agent communication languages, we show how propositional commitments are related to public beliefs and action commitments to public goals.

IEEE Intelligent Systems, 2015

Developing and implementing a model checker dedicated to conditional commitment logic with the user interface are urgent requirements for determining whether agents comply with their commitment protocols.

2006

Social commitments are developed for multi-agent systems according to the current practice in law regarding contract formation and breach. Deafeasible commitments are used to provide a useful link between multi-agent systems and legal doctrines. The proposed model makes the commitments more expressive relative to contract law and it stresses the representational rather than the operational side of the commitment life cycle. As a consequence, the broader semantics helps in modeling different types of contracts (gratuitous promises, unilateral contracts, bilateral contracts, and forward contracts) and negotiation patterns. The semantics of higher-order commitments is useful in deciding whether to sign an agreement or not and to represent a larger variety of protocols and legal contracts.

Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence, 2021

A flexible communication protocol is necessary to build a decentralized multiagent system whose member agents are not coupled to each other's decision making. Information-based protocol languages capture a protocol in terms of causality and integrity constraints based on the information exchanged by the agents. Thus, they enable highly flexible enactments in which the agents proceed asynchronously and messages may be arbitrarily reordered. However, the existing semantics for such languages can produce a large number of protocol enactments, which makes verification of a protocol property intractable. This paper formulates a protocol semantics declaratively via inference rules that determine when a message emission or reception becomes enabled during an enactment, and its effect on the local state of an agent. The semantics enables heuristics for determining when alternative extensions of a current enactment would be equivalent, thereby helping produce parsimonious models and yiel...

2004

Commitments are a powerful abstraction for representing the interactions between agents. Commitments capture the content of the interactions declaratively and allow agents to reason about their actions. Recent work on multiagent protocols define agent interactions as the creation and manipulation of commitments to one another. As a result, commitment protocols can be executed flexibly, enabling the agents to cope with exceptions that arise at run time.

Lecture Notes in Computer Science, 2013

Multiagent systems contain agents that interact with each other to carry out their activities. The agents' interactions are usually regulated with protocols that are assumed to be defined by designers at design time. However, in many settings, such protocols may not exist or the available protocols may not fit the needs of the agents. In such cases, agents need to generate a protocol on the fly. Accordingly, this paper proposes a method that can be used by an agent to generate commitment protocols to interact with other agents. The generation algorithm considers the agent's own goals and capabilities as well as its beliefs about other agents' goals and capabilities. This enables generation of commitments that are more likely to be accepted by other agents. We demonstrate the workings of the algorithm on a case study.