Security control brought back to the user [Elektronische Ressource] / Juri Luca De Coi

Security controlbrought back to the userVon der Fakult at fur Elektrotechnik und Informatikder Gottfried Wilhelm Leibniz Universit at Hannoverzur Erlangung des Grades einesDOKTORS DER NATURWISSENSCHAFTENDr. rer. nat.genehmigte DissertationvonDipl.-Ing. Juri Luca De Coigeboren am 1. November 1979 in Hagen2010Referenten:Prof. Antonio NataliAlma Mater Studiorum { Universit a di BolognaProf. Wolfgang NejdlGottfried Wilhelm Leibniz Universit at HannoverTag der Promotion: 11. Mai 2010iiRingraziamenti { Danksagung { AcknowledgmentsA joint Ph.D. is a challenge not only for the Ph.D. candidate, who has both theprivilege and the burden to get in touch with di erent ways of thinking, but also forpeople assisting her, who sometimes have to face non-trivial (bureaucratic) problems.For this reason, I owe my gratitude to my supervisors Antonio Natali and Wolfgang Nejdl my further referees Evelina Lamma and Matthew Smith the Ph.D. student managers Paolo Bassi and Paola MelloI would also like to thank Daniel Olmedilla (resp. Peter Fankhauser), who led aninexperienced (resp. not completely inexperienced) Ph.D. student along his way, aswell as the colleagues with whom I shared ideas, visions and work, especially PhilippK arger, Arne Wolf K osling and Sergej Zerr.Dass in mir der Wunsch ub erhaupt entstanden ist ins Ausland zu ziehen, ver-danke ich Julija Samsonova. Einen unentbehrlichen Beitrag zur Erful lung diesesWunsches trug Doris Anita H ohmann.