An Introduction to Multiagent Systems

From An Introduction to Multiagent Systems

Multiagent systems are systems composed of multiple interacting computing ele- ments, known as agents. Agents are computer systems with two important capa- bilities. First, they are at least to some extent capable of autonomous action – of deciding for themselves what they need to do in order to satisfy their design objec- Lives. Second, they are capable of interacting with other agenls – not simply by exchanging data, but by engaging in analogues of the kind of social activity that we all engage in every day of our lives: cooperation, coordination, negotiation, and the like.

—Multiagent systems are a relatively new sub-field of computer science – they have only been studied since about 1980, and the field has only gained widespread recognition since about the mid-1 QQOs. However, since then international interest in the field has grown enormously. This rapid growth has been spurred at least in part by the belief that agents are an appropriate software paradigm through which to exploit the possibilities presented by massive open distributed systems – such as the Internet. Although they will certainly have a pivotal role to play in exploiting the potential of the Internet, there is a lot more to multiagent systems than this. Multiagent systems seem to be a natural metaphor for understanding and building a wide range of what we might crudely call artificial social systems. The ideas of multiagent systems are not tied to a single application domain, but, like objects before them, seem to find currency in a host of different application domains.

My intention in writing this book is simple. I aim to introduce the main issues in the theory and practice of multiagent systems in a way that will be accessible to anyone with a basic background in computer science/IT. The book is deliberately intended to sit on the fence between science and engineering. Thus, as well as discussing the principles and issues in the theory of multiagent systems (i.e. the science of multiagent systems), I very much hope that I manage to communicate something of how to build such systems (i.e. multiagent systems engineering).

The multiagent systems field can be understood as consisting of two closely interwoven strands of work. The first is concerned with individual agents, while the second is concerned with collections of these agents. The structure of the book reflects this division. The first part of the book – Chapter 1 – sets the scene by discussing where the multiagent system field emerged from, and presenting some visions of where it is going. The second part – Chapters 2-5 inclusive—arc con- cerned with individual agents. Following an introduction to the concept of agents, their environments, and the various ways in which we might tell agents what to do, I describe and contrast the main techniques that have been proposed in the literature for building agents. Thus I discuss agents that decide what to do via logical deduction, agents in which decision making resembles the process of prac- tical reasoning in humans, agents that do not explicitly reason at all, and, finally, agents that make decisions by combining deductive and other decision-making mechanisms. In the third part of the book – Chapters 6-10 inclusive – 1 focus on collections of agents. Following a discussion on the various ways in which multi- agent encounters and interactions can be classified, I discuss the ways in which self-interested agents can reach agreements, communicate with one another, and work together. 1 also discuss some of the main approaches proposed for designing multiagent systems. The fourth and final part of the book presents two advanced supplemental chapters, on applications of agent systems, and formal methods for reasoning about agent systems, respectively.