One of the characteristics of design is that designers rely extensivel
y on past experience in order to create new designs. Because of this,
memory-based techniques from artificial intelligence which help store,
organise, retrieve, and reuse experiential knowledge held in memory a
re good candidates for aiding designers. Another characteristic of des
ign is the phenomenon of exploration in the early stages of design con
figuration. A designer begins with an ill structured, partially define
d, problem specification, and through a process of exploration gradual
ly refines and modifies it as his/her understanding of the problem imp
roves. The paper describes DEMEX, an interactive computer-aided design
system that employs memory-based techniques to help its users explore
the design problems they pose to the system, so that they can acquire
a better understanding of the requirements of the problems. DEMEX has
been applied in the domain of the structural design of buildings.