Thesis - Instituto de Telecomunicações

4 CHAPTER 1. INTRODUCTIONThe main goals of the thesis are the following: (1) proposal and testing of new biometrictraits; (2) creation of a signal database from the indicated signal sources to be used in identityand behavioral studies; (3) development and evaluation of signal models; (4) design andimplementation of signal processing and feature extraction tools; (5) creation of behavioralbiometrics classification systems; (6) proposal of behavioral biometrics classification fusiontechniques.Additionally, we addressed the following other questions: what is the discriminativecapacity of each type of signal; in which conditions can the signals be used; in which contextsare the proposed techniques soft-biometrics and how can these techniques be usedas a stronger validation biometric system; how and what are the possibilities of combiningthese signals with other biometric modalities in order to have an overall performanceenhancement, from a multimodal biometric approach.1.2 Motivation1.2.1 BiometricsThe problem of biometric identification is an active research field and its expansion isfocusing on new traits for multimodal combination. Particularly, behavioral traits haverecently obtained relevant performance increase, bringing overall discriminative capacityimprovement to multimodal biometric systems.Behavioral biometrics is an active research area with interesting open topics where amultidisciplinary approach, supported on signal processing and modeling and on patternrecognition techniques, could provide relevant and original contributions. These were themain motivation for the present thesis work.The ubiquitous computer environments in current networked societies, also motivatedthe challenge to create a remote biometric system. The challenge that led to the proposalof an original system based only on the user interaction in a web page, that we have namedWebBiometrics (see chapter 7).We were also interested in recent trends concerning privacy issues. The principle ofprivacy directs biometrics systems to use only the information needed. The biometricsystem should be adapted to the proportion of the required identification needs [19]. Some