Stuart Russell and Peter Norvig - Artificial Intelligence - A Modern Approach (3rd ed.) (1)

In our discussion of the rationality of the simple vacuum-cleaner agent, we had to specify the performance measure. the environment, and the agent's actuators and sensors. We group all these under the heading of the task environment. For the acronymically minded, we call PEAS this the PEAS (Performance, Environment, Actuators, Sensors) description. In designing an agent, the first step must always be to specify the task environment as filly as possible The vacuum world was a simple example; let us consider a more complex problem: an automated taxi driver. We should point out, before the reader becomes alarmed, that a fully automated taxi is currently somewhat beyond the capabilities of existing technology. (page 28 describes an existing driving robot.) The full driving task is extremely open-ended. There is no limit to the novel combinations of circumstances that can arise—another reason we chose it as a focus for discussion Figure 2A summarizes the PEAS description for the taxi's task environment. We discuss each element in more detail in the following paragraphs.