Internal Structure of Agents

We have looked at agents in terms of their external influences and behaviors: they take input from the environment and perform rational actions to alter that environment. We will now look at some generic internal mechanisms which are common to intelligent agents.

• Architecture and Program

The  program of an  agent  is  the  mechanism  by  which  it  turns  input  from the environment into an action on the environment. The architecture of an agent is the computing device (including software and hardware) upon which the program operates. On this course, we mostly concern ourselves with the intelligence behind the programs, and do not worry about the hardware architectures they run on. In fact, we will mostly assume that the architecture of our agents is a computer getting input through the keyboard and acting via the monitor.

RHINO consisted of the robot itself, including the necessary hardware for locomotion (motors, etc.) and state of the art sensors, including laser, sonar, infrared and tactile sensors. RHINO also carried around three on-board PC workstations and was connected by a wireless Ethernet connection to a further three off-board SUN workstations. In total, it ran up to 25 different processes at any one time, in parallel. The  program  employed   by  RHINO  was   even  more  complicated  than  the architecture upon which it ran. RHINO ran software which drew upon techniques ranging from low level probabilistic reasoning and visual information processing to high level problem solving and planning using logical representations.

An agent's program will make use of knowledge about its environment and methods for deciding which action to take (if any) in response to a new input from the environment. These methods include reflexes, goal based methods and utility based methods.