Problems with A Heart-Shaped Curve

(full version printed; summary, abstracts, and some articles online) by Novática, journal of the Spanish CEPIS society ATI (Asociación de Técnicos de Informática) at , and in Italian (online edition only, containing summary, abstracts, and some articles) by the Italian CEPIS society ALSI (Associazione nazionale Laureati in Scienze dell'informazione e Informatica) and the Italian IT portal Tecnoteca at . UPGRADE is the anchor point for UPENET (UPGRADE European NETwork), the network of CEPIS member societies' publications, that currently includes the following ones: • Mondo Digitale, digital journal from the Italian CEPIS society AICA • Novática, journal from the Spanish CEPIS society ATI • OCG Journal, journal from the Austrian CEPIS society OCG • Pliroforiki, journal from the Cyprus CEPIS society CCS • Pro Dialog, journal from the Polish CEPIS society PTI-PIPS