Rogier M. van Eijk

A Dialogue Game Protocol for Agent Purchase Negotiations

We propose a dialogue game protocol for purchase negotiation dialogues which identifies appropriate speech acts, defines constraints on their utterances, and specifies the different sub-tasks agents need to perform in order to engage in dialogues according to this protocol. Our formalism combines a dialogue game similar to those in the philosophy of argumentation with a model of rational consumer purchase decision behaviour adopted from marketing theory. In addition to the dialogue game protocol, we present a portfolio of decision mechanisms for the participating agents engaged in the dialogue and use these to provide our formalism with an operational semantics. We show that these decision mechanisms are sufficient to generate automated purchase decision dialogues between autonomous software agents interacting according to our proposed dialogue game protocol.

ANEMONE: an effective minimal ontology negotiation environment

Communication in open heterogeneous multi agent systems is hampered by lack of shared ontologies. To overcome these problems, we propose a layered communication protocol which incorporates techniques for ontology exchange. Using this protocol, the agents gradually build towards a semantically integrated system by establishing minimal and effective shared ontologies. We tested our approach, called ANEMONE, on a number of heterogeneous news agents. We show how these agents successfully exchange information on news articles, despite initial difficulties raised by heterogeneous ontologies.

Ontological Feedback in Multiagent Systems

In this paper, we present a computational framework for the detection of ontological discrepancies in multiagent systems. The framework is developed as a basis for the generation of feedback utterances at the ontological level. In our method, presuppositions are extracted from the senders message, expressed in a common vocabulary, and compared with the recipients ontology, which is expressed in type theory. Discrepancies are detected by the receiving agent if it notices type conflicts, particular inconsistencies or ontological gaps. Depending on the kind of discrepancy, the agent generates a particular feedback message in order to establish alignment of its private ontology with the ontology of the sender.

Ontology negotiation: goals, requirements and implementation

Communication in heterogeneous Multi-Agent Systems (MASs) is hampered by the lack of shared ontologies. Ontology negotiation offers an integrated approach that enables agents to gradually build towards a semantically integrated system by sharing parts of their ontologies. This solution involves a combination of a normal agent communication protocol with an ontology alignment protocol. For such a combination to be successful, it must satisfy several criteria. This paper discusses the goals and requirements that are important for any ontology negotiation protocol. Furthermore, we will propose some implementations that are constructed according to these criteria.

Operational Semantics for Agent Communication Languages

In this paper, we study the operational semantics of agent communication languages. We develop a basic multi-agent programming language for systems of concurrently operating agents, into which agent communication languages can be integrated. In this language, each agent has a mental state comprised of an informational component and a motivational component; interaction between the agents proceeds via a rendezvous communication mechanism. The language builds upon well-understood concepts from the object-oriented programming paradigm as object classes, method invocations and object creation. The formal semantics of the language are defined by means of transition rules that describe its operational behaviour. Moreover, the operational semantics closely follow the syntactic structure of the language, and hence give rise to an abstract machine to interpret it.

A Verification Framework for Agent Communication

In this paper, we introduce a verification method for the correctness of multiagent systems as described in the framework of ACPL (Agent Communication Programming Language). The computational model of ACPL consists of an integration of the two different paradigms of CCP (Concurrent Constraint Programming) and CSP (Communicating Sequential Processes). The constraint programming techniques are used to represent and process information, whereas the communication mechanism of ACPL is described in terms of the synchronous handshaking mechanism of CSP. Consequently, we show how to define a verification method for ACPL in terms of an integration of the verification methods for CCP and CSP. We prove formally the soundness of the method and discuss its completeness.

A fully abstract model for the exchange of information in multi-agent systems

In this paper,11This paper is an extended version of 7]. we present a semantic theory for the exchange of information in multi-agent systems. We consider the multi-agent programming language agent communication programming language, which integrates the paradigms of concurrent constraint programming and communicating sequential processes (CSP). The constraint programming techniques are used to represent and process information, whereas the synchronous communication mechanism from CSP is generalised to enable the exchange of information. The semantics of the language, which is based on a generalisation of traditional failure semantics, is shown to be fully abstract with respect to observing of each terminating computation its final global store of information.

Open Multi-agent Systems: Agent Communication and Integration

In this paper, we study the open-ended nature of multi-agent systems, which refers to the property of allowing the dynamic integration of new agents into an existing system. In particular, the focus of this study is on the issues of agent communication and integration. We define an abstract programming language for open multi-agent systems that is based on concepts and mechanisms as introduced and studied in concurrency theory. Moreover, an important ingredient is the generalisation of the traditional concept of value-passing to a communication mechanism that allows for the exchange of information. Additionally, an operational model for the language is given in terms of a transition system, which allows the formal derivation of computations.

Optimal communication vocabularies and heterogeneous ontologies

In this paper, we will consider the alignment of heterogeneous ontologies in multi agent systems. We will start from the idea that each individual agent is specialized in solving a particular task and therefore requires its own specialized ontology that is, in principle, not understandable for other agents. This heterogeneity of ontologies, of course, poses problems for the communication between agents. In our framework, we assume that the agents share some minimal common ground which can be used to learn new concepts. We will discuss which concepts of the different ontologies the agents should learn from each other in order to establish a communication vocabulary that enables optimal communication.

Process algebra for agent communication: a general semantic approach

In this paper, we consider the process algebra ACPL, which models the basics of agent communication. This algebra combines the information-processing aspects of Concurrent Constraint Programming (CCP) with a generalisation of the synchronous handshaking communication mechanism of Communicating Sequential Processes (CSP). The operational semantics of ACPL is given in terms of a transition system that consists of local and global transition rules. The local rules describe the operational behaviour of agents, like the local effects of communication actions. The global rules define the operational behaviour of multi-agent systems including the matching of communication actions. We show how ACPL provides a general basis to address the semantics of agent communication languages such as KQML and FIPA-ACL. Finally, we address several extensions of the basic algebra.