CombiningFeatures and Semantics:Advanced Methodsfor Content-based RetrievalInaugural-DissertationzurErlangung des Doktorgrades derMathematisch-Naturwissenschaftlichen Fakultatder Heinrich-Heine-Universitat Dusseldorf vorgelegt vonJohanna Vomprasaus PyrzyceJanuar 2009Aus dem Institut fur Informatikder Heinrich-Heine Universitat DusseldorfGedruckt mit der Genehmigung derMathematisch-Naturwissenschaftlichen Fakultat derHeinrich-Heine-Universitat Dusseldorf Referent: Prof. Dr. Stefan ConradKoreferent: Prof. Dr. Martin MauveTag der mundlichen Prufung: 08.07.2009 Dedicated toAngelosAcknowledgementsThis thesis summarizes my research at the Databases and Information SystemsGroup of the Department of Computer Science at the Heinrich Heine University ofDusseldorf, where I have been working as a research assistant since June 2004.I acknowledge my thesis advisor and rst referee, Prof. Dr. Stefan Conrad, for pro-viding a motivating atmosphere and giving constructive comments during my researchtime as well as on the preliminary version of this thesis. It was a great pleasure forme to pursuit research under his supervision. I also thank the second reviewer of thisthesis, Prof. Dr. Martin Mauve, for his interest in my work and willingness to be thesecond referee.