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Defender: MSc Teppo Tossavainen. Born in Tervo. Opponents: Prof. Klaus-Dieter Thoben from University of Bremen and Dr. Heikki Hämmäinen from Nokia. Title of the thesis: System Usability of Complex Technical Systems. Complexity catastrophe for the mobile telephone networks? Extensive modern technical systems are very complicated: consider, for example, mobile telecommunication systems, industrial process control systems or flight traffic control systems. When the complexity of a technical system grows beyond a certain limit, the probability of error and complexity catastrophes increases also. Mr. Tossavainen studies the usability of complex technical systems in an internationally unique manner in his doctoral thesis by drawing on biology and complexity research, and applying the theories to technical evolution. He also introduces means for managing the complexity of technical systems.
Mr. Tossavainen defines the system usability of a technical system by using the total effort of operating the system. System usability considers all the required measures for planning, building, using and optimising the system, as well as managing the services. He also introduces a way of measuring and comparing the system usability of different systems, whereby a system having better usability is characterised by a lower effort to operate it. As usability has conventionally been the domain of cognitive science, it has mainly concentrated on the Human-Computer-Interface (HCI). Jukka Ranta, who is working in a hi-tech company, enjoys his stay at Laajalahti, amidst complex phenomena of nature. He also sees an analogy between nature and complex technical systems. -The defender of the thesis creates a new approach, which facilitates the design of complex interactive technical systems so that they are easier to handle. We have to make the system usability competitive particularly in those rapidly growing fields, which also have many basic technology problems to solve, says the docent of automation technology in HUT, and one of the reviewers of the thesis, Jukka Ranta. In the empirical part of the thesis, Mr. Tossavainen applies his system usability approach to GSM-networks from the teleoperator point of view. According to the results, the system usability is rather modest. The technical solutions of the present systems are not very optimal because, among other things, the new features are usually built on top of the older solutions without ever removing or redesigning any of the underlying technology. -The defender brings complexity theory to a new application field: mobile telephone networks. The mobile network business has grown very fast and it would be justified to use the system usability approach for designing, maintaining and user training in the new and increasingly more complex technical systems, says Dr. Ranta - we also have to remember that even the present mobile networks are probably among the most complex man-made systems ever. The work also makes use of a so-called adaptive landscape concept in studying several interacting systems in a dynamic, ever-changing environment. The technical product development in hi-tech companies can be understood as 'hill-climbing' in the adaptive landscape by selecting certain ingredient combinations from a huge space of possibilities. These companies live in coevolution with each other, thus moulding each other's adaptive landscapes. By combining the created new approach with a good system usability of the technology, a company has better chances for successful development of new complex technical systems. Teppo Tossavainen tells that his inspiration for creating this approach was sparked by an exceptional seminar book in the Helsinki University of Technology: Stuart Kauffman (1992): The origins of order - Self-organization and selection in evolution, Oxford University Press, New York. |
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