A method is proposed and analysed for servicing keyword queries expressed i
n a digital library. Efficiency in the service routine is introduced via th
e concept of customers and producer. From the customer perspective, queries
are grouped into clusters of similar concepts. The action of the servicing
digital library is then formulated in terms of the amount of overlap each
cluster of queries has with respect to the information density of the libra
ry. Furthermore, the concept of query priorities is incorporated within the
formulation of the initial query clusters. The ensuing combination of prio
ritised query clustering and fuzzy decision-making is shown to ensure that
the prioritised query instances receive preferential service times without
increasing the query queue length or delay times. (C) 2000 Elsevier Science
Ltd. All rights reserved.