Discriminative Preprocessing of Speech: Towards Improving Biometric Authentication Dissertation zur Erlangung des akademischen Grades eines Doktors der Philosophie der Philosophischen Fakultäten der Universität des Saarlandes vorgelegt von Dalei Wu aus Han Dan, China Saarbrücken, 2006 __________________________________________________________________________________ Die Dekanin: Univ.Prof. Dr. Ulrike Demske Berichterstatter: Prof. Dr. William Barry Prof. Dr. Dietrich Klakow Prof. Dr. Jacques Koreman Tag der letzten Prüfungsleistung: 21.07.2006iii The dissertation of Dalei Wu is approved and is acceptable in quality and form for publication on microfilm: ________________________________________ ________________________________________ ________________________________________ ________________________________________ Committee Chair Saarland University, Saarbrücken 2006 v Dedication To my wife and my daughter for their endless love, patience and encouragement. Also to my parents and brother, without their support, I could never have succeeded. vii Table of Contents Part I. General background: Speech and other biometrics......................1 1. Introduction..................................