Motivation
Multi-agent
systems (MAS) can typically become very complex and their behaviors
can be hard to specify. Since, by definition, a MAS consists of a group
of autonomous agents, one of the key challenges in designing a MAS is
coordinating the actions of the agents. In a dynamic environment where
the actions of the agents are also interdependent on each other, it
is especially critical that the agents learn to adapt their actions
to the actions of other agents. Furthermore, when designing agent systems
it is impossible to foresee all the potential situations an agent may
encounter and define behavioral repertoires and activities optimally
in advance. Agents therefore have to learn from, and adapt to, their
environment, especially in a multi-agent setting.
Until recently, research in the field of machine learning (ML) mainly
concentrated on learning techniques and methods in single-agent or isolated-system
settings. More and more, ML is being explored as a vital component to
address challenges in multi-agent systems. For example, many application
domains are envisioned in which teams of software agents or robots learn
to cooperate amongst each other and with human beings to achieve global
objectives. Learning may also be essential in many non-cooperative domains
such as economics and finance, where classical game-theoretic solutions
are either unfeasible or inappropriate.
At the same time, multi-agent learning poses significant theoretical
challenges, particularly in understanding how agents can learn and adapt
in the presence of other agents that are simultaneously learning and
adapting. This is a fertile area of research that seems ripe for progress:
the numerous and significant theoretical developments of the 1990s,
in fields such as Bayesian, game-theoretic, decision-theoretic, and
evolutionary learning, can now be extended to more challenging multi-agent
scenarios.
Perspectives
We see two main streams of MAS research that incorporate learning: (1)
MAS that incorporate learning into the agents so that the agents learn
to adapt to their environment, and (2) MAS systems designed for learning
tasks or for discovering new knowledge (for e.g., data mining).