Approaches for Solving the Classification Problem

Given the process topology, an unoriented graph is built where nodes correspond to units and arcs represent process streams. The process graph contains an environment node from which the process receives feeds, and to which it supplies products. 

The main contributions to the development of graph-oriented techniques are due to the following authors. 

Vaclavek (1969) first defined the concepts of observability and redundancy. He formulated two rules for achieving variable categorization for linear plant models  

Delete all measured streams and search for cycles on the reduced graph. The cycles in the resulting graph represent indeterminable flows. 

Vaclavek and Loucka (1976) extended the approach to multicomponent processes with the assumption that, for any stream, either all or none of the mass fractions are 

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