Introduction Agents operate and exist in some environment, which typically is both computational and physical. The environment might be open or closed, and it might or might not contain other agents. Although there are situations where an agent can operate usefully by itself, the increasing interconnection and networking of computers is making such situations rare, and in the usual state of affairs the agent interacts with other agents. Whereas the previous chapter defined the structure and characteristics of an individual agent, the focus of this chapter is on systems with multiple agents. At times, the number of agents may be too numerous to deal with them individually, and it is then more convenient to deal with them collectively, as a society of agents. In this chapter, we will learn how to analyze, describe, and design environments in which agents can operate effectively and interact with each other productively. The environments will provide a computational infrastructu

Electronic messaging—whether in an office environment or for electronic commerce—is normally carried out in natural language, even when supported by information systems. For a variety of reasons it would be useful if electronic messaging systems could have semantic access to, i.e., have access to the meanings and contents of, the messages they process. Given that natural language understanding is not a practicable alternative, there remain three approaches to delivering systems with semantic access: electronic data interchange (EDI), tagged messages, and the development of a formal language for business communication (FLBC). We favor the latter approach. In this paper we compare and contrast these three approaches, present a theoretical basis for an FLBC (using speech act theory), and describe a prototype implementation.

Abstract. This paper gives an overview of our recent work on an approach to verifying multi-agent programs. We automatically translate multi-agent systems programmed in the logic-based agent-oriented programming language AgentSpeak into either Promela or Java, and then use the associated Spin and JPF model checkers to verify the resulting systems. We also describe the simplified BDI logical language that is used to write the properties we want the systems to satisfy. The approach is illustrated by means of a simple case study.

We analyze a general model of multi-agent communication in which all agents communicate simultaneously to a message board. A genetic algorithm is used to evolve multi-agent languages for the predator agents in a version of the predator-prey pursuit problem. We show that the resulting behavior of the communicating multi-agent system is equivalent to that of a Mealy finite state machine whose states are determined by the agents' usage of the evolved language. Simulations show that the evolution of a communication language improves the performance of the predators. Increasing the language size (and thus increasing the number of possible states in the Mealy machine) improves the performance even further. Furthermore, the evolved communicating predators perform significantly better than all previous work on similar preys. We introduce a method for incrementally increasing the language size which results in an effective coarse-to-fine search that significantly reduces the evolution time required to find a solution. We present some observations on the effects of language size, experimental setup, and prey difficulty on the evolved Mealy machines. In particular, we observe that the start state is often revisited, and incrementally increasing the language size results in smaller Mealy machines. Finally, a simple rule is derived that provides a pessimistic estimate on the minimum language size that should be used for any multi-agent problem. 1

We consider the problem of how agents should be named and what kind of software infrastructure is necessary in order to locate an agent given only its name. We assume an agent environment which (1) is dynamic with agents being created and destroyed frequently; (2) undergoes re-organizations with agent groups and sub-groups forming and disbanding; and (3) supports agent communication by any of several transport mechanisms such as TCP/IP, email, http and distributed object systems. This leads us to propose the establishment of agent domains which are organized into an agent domain hierarchy. Agent name resolution can be done by agent name servers, analogous to Internet domain name servers. One of the additional benefits from this approach is that it easily supports the definition of proxy agents. We sketch how this proposal would impact the KQML agent communication language and protocol and describe an ongoing implementation of a generic KQML Agent Name Server and its integration into t...

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. In this paper we describe the rst ideas for formalizing a communication protocol for mathematical services based on Kqml (Knowledge Query and Manipulation Language) and OMRS (Open Mechanized Reasoning Systems). The claim is that the interaction level of a communication protocol for mathematical services can be relatively generic (hence Kqml suces), as long as the ontology of the computational behavior and internal state of the mathematical services is suciently expressive and concise (which we have in OMRS). The material presented in this paper is a rst exploratory step towards the denition of the interaction level in OMRS, supplies a concrete syntax based on the OpenMath standard, and gives a semantics to communication of mathematical services in distributed theorem proving and symbolic computation environments. 1 Introduction It is plausible to expect that the way we do (conceive, develop, communicate about, and publish) mathematics will change considerably in the next ten ye...

We describe the initial results of a project aimed at adapting the Cyc system for use in an agent architecture. Two Cyc systems that share a large common core of knowledge but differ in additional knowledge they possess were able to reason together to solve problems that neither could solve on its own. A rudimentary interface was constructed for Cyc that allowed it to communicate with other KQML-speaking agents. The Cyc reasoning algorithm was modified to allow it to ask other agents for help in developing a proof to answer a query. We were able to demonstrate that Cyc can be adapted to work in an agentoriented architecture and to get several Cyc-based agents to reason in a tightly-coupled manner. A number of interesting research issues remain concerning how to do so efficiently. 1 This work was supported in part by the Department of Defense under contract MDA904-95-C-2084, by the Air Force Office of Scientific Research under contract F49620-92-J-0174, and by the Advanced Research Pro...

Although much progress has been made in agent theory and practice, bottlenecks remain in the construction of complex multiagent systems. We introduce interaction-oriented programming (IOP) as an approach to orchestrate the interactions among agents. IOP is more tractable and practical than general agent programming, especially in settings such as open information environments, where the internal details of autonomously developed agents are not available. IOP facilitates multiagent system design by enabling declarative specification and enactment of agent interactions, thereby channeling the intellectual energies of designers into the most amenable and effective design tasks. We develop an event algebra to specify interactions among agents. We automatically compile these declarative specifications into executable temporal logic constraints. These are efficiently processed at run-time to produce the desired behavior in a distributed manner. We have implemented the above modules in a (co...

. Autonomous agents decide for themselves, on the basis of their beliefs, goals, etc., how to act in an environment. However, it is often the case that an agent is motivated to achieve some goal, where its achievement is only possible, made easier, or satisfied more completely, by gaining the collaboration of others. This collaboration requires the agents to communicate with one another in negotiation and in the coordination of their action. In this paper, it is assumed that such collaboration requires the agents involved to have some prior agreement on the actions that each can call on the others to do; their respective rights. A novel framework is introduced for describing agreements between agents based on rights, and it is indicated how agents may generate such agreements through negotiation. In particular, we focus on a discussion of the structure of an agreement, what it means for an agent to be committed to an agreement, and the communicative actions that agents use in the gene...