5.2.1 Task‐oriented System Engineering

Traditional system engineering (SE) is technology driven. In the design of interactive systems we typically assume that the human operator traces the changes in the system states and operates the system correctly. However, the human operator obeys different rules. The difference between the designers' and the operator's rules often results in loss of productivity, decreased performance and accidents, and eventually, loss of market share. In special cases, it makes sense to demand that the user follows the designers' logic. However, in most projects, it is the designer who needs to adapt to the user's logic. The article analyzes the limitations of common design practices in resolving mismatches between the system and the user states. Complex system engineering (CSE) is a framework suitable for handling the human operator as a critical system component. This article presents a methodology for handling the human attributes in this framework. The methodology extends the capability of common practices of user-centered design and usability testing, which miss critical interdisciplinary issues. To resolve state mismatches, the system engineers must be aware of the user's logic. Such knowledge should be reflected in the system architecture, to ensure that the user interface provides protection against unexpected user events and to facilitate the system operation in new situations, such as in emergency. The methods and guidelines presented here are applicable to the whole development cycle.