TCD-CS-93-04 Cunningham, P., Smyth, B., Finn, D. & Cahill, E.

June 1993.

Retrieval issues in CBR systems for routine and non-routine design


We propose that analogical reasoning and case based reasoning (CBR) tasks can be useful characterised as a continuum reflecting the remoteness of the remindings involved. Remindings in CBR are generally between semantically close case while analogical reasoning depends on more abstract remindings. Rather than there being a strict demarcation between CBR and analogical reasoning on these grounds (with analogical reasoning concerned with inter domain remindings and CBR dealingwith remindings within one domain) there is a continuum of cognitive tasks that draw on past experience during reasoning. Simpler tasks like diagnosis and classification are located nera the CBR end. The question is how far the abstract end of continuum can can the index-base retrieval techniques that are effective in CBR be used (eg. discrimination networks). We are considering episode retrieval as a two stage process; the first stage being the initial filtering of the case base, and the second being selecting the best case from this candidate set. We focus on the base filtering stage and conclude that discrimination networks are adequate for comparatively complex cognitive tasks such as routine design. However, we argue that CBR systems for non-routine design should provide interactive case retrieval and act as CBR assistants.

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