UNIVERSIT ` A DEGLI S TUDI DI P ISA DIPARTIMENTO DI I NFORMATICA DOTTORATO DI R ICERCA IN I NFORMATICA P H.D. T HESIS: TD 5/04 High Performance Issues in Web Search Engines: Algorithms and Techniques. Fabrizio Silvestri S UPERVISOR dr. Raffaele Perego REFEREE Prof. Guy E. Blelloch REFEREE Dr. Ronny Lempel May 2004 Addr: Via F. Buonarroti 2, 56127 Pisa Italy Tel: +39-050-315 3011 Fax: +39-050-313 8091 E-mail: fasilves@di.unipi.it Web: http://hpc.isti.cnr.it/∼silvestr