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P9313   S.F.M. van Vlijmen & A. van Waveren
        "Algebraic specification of a system for traffic regulation at
        signalized intersections"


A specification of a part of an existing system for traffic regulation at 
signalized intersections is given. The system that is chosen as subject to 
specification is developed by the dutch company Nederland Haarlem. 
The specification, in PSF, centers on the algorithm performing the regulation, 
which is, in our view, the most interesting part. The specification given is 
data-oriented, i.e., there is not much emphasis on processes. Although time 
plays an important role in the regulation process, this is not an obstacle 
for specification.