The Importance of Models in Making Complex Systems Comprehensible

Reality is not user-friendly. To cope with, model, and comprehend a complex reality requires complex systems. Complex systems offer power, but they are not without problems. In our research, high functionality computer systems serve as prototypical examples for complex systems and are used to instantiate our framework of cooperative problem solving in joint human-computer systems. Models play a crucial role in the creation and use of these systems and help to increase their comprehensibility. Three different types of models are discussed in this paper: the designers' models of users, the users' models of systems, and the systems' models of users. Innovative system designs supporting human problem-domain communication and providing design environments illustrate the relevance of these models in making complex systems comprehensible. Introduction We are interested in the design and understanding of highfunctionality computer systems. These systems contain thousands of objects, and they are not completely mastered even by expert users. An important question to ask is: What kind of models are needed for the design, comprehension, and use of such systems? High-functionality computer systems are designed systems. To comprehend designed systems, we have to understand the goals, functions, and adaptive capabilities for which they are used. The models associated with these systems are part of the design (i.e., they must be designed too), and they can and should provide important requirements for the design. '" ,~,' ¥ '" " , , ~ ~ ,,' , ,( ~~ • • ' ,> " ". .. .