The Portuguese Association for Arti cial Intelligence (APPIA) has been re- larly organising the Portuguese Conference on Arti cial Intelligence (EPIA). This ninth conference follows previous ones held in Porto (1985), Lisboa (1986), Braga (1987), Lisboa (1989), Albufeira (1991), Porto (1993), Funchal (1995) and Coimbra (1997). Starting in 1989, the conferences have been held biennially (alternating with an APPIA Advanced School on Arti cial Intelligence) and become truly international: English has been adopted as the o cial language and the proceedings are published in Springer's LNAI series....