This volume consitutes a summary of several years' multi-disciplinary research by a group of Swedish researchers. The project 'Sweden's Technological Systems and Future Development Potential' was initiated by the Swedish National Board for Industrial and Technical Development (NUTEK) and has been carried out at the Department of Industrial Management and Economics at Chalmers University of Technology in Gothenburg, the Research Policy Institute at the University of Lund, the Industrial Institute for Economic and Social Research (lUI) in Stockholm, and the Department of Industrial Economics...

Temporal databases have been an active research topic for at least fifteen years. During this time, several dozen temporal query languages have been proposed. Many within the temporal database research community perceived that the time had come to consolidate approaches to temporal data models and calculus based query languages, to achieve a consensus query language and associated data model upon which future research can be based. While there were many query language proposals, with a diversity of language and modeling constructs, common themes kept resurfacing. However, the community was...