In preliminary experiments, we found this definition to be stable during normal behavior for several standard UNIX programs. Further, it is able to detect several common intrusions involving sendmail and other processes. In collaboration with John Holland, Terry Jones, Peter Hraber, Andrew Kosoresow, and several ecologists, we are studying how genetic algorithms can be used in ecological modeling. In Echo, fitness evaluation takes place implicitly. However these resources can exist independently of the agent's genome, either free in the environment or stored internally by the agent.
Agents acquire resources by interacting with other agents through trading relationships and combat.
Echo thus relaxes the constraint that an explicit fitness function must return a numerical evaluation of each agent. Mating provides opportunities for agents to exchange genetic material through crossover, thus creating hybrids. Mating, together with mutation, provides the mechanism for new types of agents to evolve. We are currently studying the extent to which macro-level behaviors of Echo mimic those of natural ecological systems. In particular, we are quantifying the species abundance patterns observed in Echo and comparing them with those found in natural ecologies.