A Rule-Based Consultant for Accelerator Beam Scheduling
used in the CERN PS Complex.
J. Lewis, P. Skarek, CERN
L. Varga (On leave from KFKI-MSZKI, Budapest, Hungary)
The CERN PS accelerator complex consists of nine interacting
accelerators which work together to produce particle beams for different end
users, varying in particle type, energy, time structure, and geometry. The beam
production schedule is time sliced, and depends on the current operational
requirements, and dynamically on the accelerator status, so that production
schedule changes occur in real time. Many potential schedules are not valid due
to various system constraints, and these constraints vary over time as new
operational modes are introduced. In order to ensure that only valid schedules
are given to the complex, an automated tool has been developed to indicate
whether a potential schedule is valid or not. This presentation describes the
method by which the validity of a beam schedule is determined and how this
method was implemented using a rule-based approach based on SQL, avoiding the
use of an expert system shell. Both the data to instantiate the rules and the
rules themselves are kept in an Oracle data base. The SQL interpreter provides
the inference engine for this knowledge based system. A few examples are
presented and the running experience with the tool is discussed.