Reasoning about signals and systems in complex measurement environment

The complexity of instruments and measurement tasks nowadays introduces new and interesting problems. Until recently signal and system theory and a huge amount of expert knowledge provided a theoretical basis for measurement planning, optimal measurement settings, verification of the measurement set-ups and diagnosis of the flow of measurement. The need for this computerised aid in the field makes a higher level description of the knowledge about these systems necessary, independently of the particular type of knowledge. This paper proposes a multilevel, hierarchical frame for describing the mathematical aspects of (analog) signal-based information processing, together with the related reasoning strategies. The direct goal of this representation is the description and diagnosis of complex measuring systems. Having several views about the system components and signals yields a more effective reasoning in situations, where not every information is available about system components. A central point of investigation is the qualitative representation of signals that allows reasoning with missing information about the underlying system.