Deleting and Building Sort Out Techniques
for Case Base Maintenance

Maria Salam and Elisabet Golobardes

Enginyeria i Arquitectura La Salle, Universitat Ramon Llull,
Psg. Bonanova 8, 08022 Barcelona, Spain
{mariasal,elisabet}@salleurl.edu



Abstract. Early work on case based reasoning reported in the literature
shows the importance of case base maintenance for successful practical
systems. Different criteria to the maintenance task have been used for
more than half a century. In this paper we present different sort out
techniques for case base maintenance. All the sort out techniques proposed 
are based on the same principle: a Rough Sets competence model.
First of all, we present sort out reduction techniques based on deletion
of cases. Next, we present sort out techniques that build new reduced
competent case memories based on the original ones. The main purpose
of these methods is to maintain the competence and reduce, as much
as possible, its size. Experiments using different domains, most of them
from the UCI repository, show that the reduction techniques maintain
the competence obtained by the original case memory. The results are
analysed with those obtained using well-known reduction techniques.
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