Mobile Agents in Healthcare, a Distributed Intelligence Approach - Computational Intelligence in Healthcare: Advanced Methodologies - page 45

requiring any network infrastructure at all. This approach is ready to be used in the worst
case scenario, where only small handheld devices carried by the emergency personnel
are available, but also integrates well when synchronous connections are possible, for
instance when a mesh network can be created.
The chapter concludes with a discussion of the lessons learnt from the development
and deployment of these applications. This discussion includes some best practices for
the effective use of mobile agents in the e-health domain.

2 Mobile Agents

2.1 Definition

Mobile agents [51] are a technology which has its origin on two different disciplines.
On the one hand, the artificial intelligence community created the concept of intelli-
gent agent [53]. On the other hand, the distributed systems community, with a more
pragmatic vision of mobile agents, exploited the code mobility [12].
A valid definition for mobile agents, regarding the two mentioned disciplines, is
that they are intelligent software entities that have the ability to stop and resume their
execution in different network locations to accomplish a set of tasks. The agents live
within environments called agent platforms, which define the boundaries of available
locations, and are characterised by a set of properties:

- Mobility: Agent ability of suspending its execution in a specific agent platform,
and resume it in another agent platform, i.e., in another location. This process is
usually called agent migration.
- Autonomy: Each agent is driven according to a code specially developed to achieve
one or more goals. The agent actions are completely decided according to this code
without direct intervention of other parties.
- Reactivity: Agents react to the environment changes in order to achieve their goals.
- Proactivity: Agents change their environment and take several initiatives to achieve
their goals.
- Sociability: It is the ability of agents to interact with other agents. This is a key
feature, since some agents only can perceive their environment through communi-
cation with other agents.

2.2 Agent Architecture

A mobile agent, from an architectural point of view, is an entity with a unique identi-
fication that is composed of three main components: code, data, and state. The agents
live in an environment called agent platform, which is managed by an agent middleware
software layer.

2.2.1 Agent Identification
Each mobile agent has an associated identifier that distinguishes it individually. This
identifier is assigned when the agent is created, it should be immutable, and it is unique
within the scope of the agent authority. The agent identification is of utmost importance
since it is related to the communication among agents.