The Role of people in Systems People can be viewed as being either inside or outside a system. For instance, an orbiting satellite communication system might work largely independently of people. However, it still has to be maintained, and its output is ultimately still going to be used by people in some way. The failure to consider the human as a system component and to design for the human user is one of the reasons why so many machines and systems are unsafef or difficult or inconvenient to use. In this course we will highlight the role of the human operator and consider systems design from that perspective.
People often bear the ultimate responsibility for system operation.
For instance, the captain of the ship or the pilot of the aircraft is expected to keep the system under control when all else fails. We can't sue automation, but we can sue people, so it is people who are ultimately responsible. This is why a high proportion of transportation accidents, for instance, are attributed to human error. We shall return to the problem of the properties of humans versus machines in lecture 9 when we consider how to allocate different tasks within a system between its human and machine components. The role of humans varies widely within systems from operators working with specific tools for specific tasks to supervisory controllers who manage other people as well as the system and whose task definition is extremely flexible, depending on the moment to moment conditions and context of the system.