Recent Application in Biometrics

In the recent years, a number of recognition and authentication systems based on biometric measurements have been proposed. Algorithms and sensors have been developed to acquire and process many different biometric traits. Moreover, the biometric technology is being used in novel ways, with potential commercial and practical implications to our daily activities. The key objective of the book is to provide a collection of comprehensive references on some recent theoretical development as well as novel applications in biometrics. The topics covered in this book reflect well both aspects of development. They include biometric sample quality, privacy preserving and cancellable biometrics, contactless biometrics, novel and unconventional biometrics, and the technical challenges in implementing the technology in portable devices. The book consists of 15 chapters. It is divided into four sections, namely, biometric applications on mobile platforms, cancelable biometrics, biometric encryption, and other applications. The book was reviewed by editors Dr. Jucheng Yang and Dr. Norman Poh. We deeply appreciate the efforts of our guest editors: Dr. Girija Chetty, Dr. Loris Nanni, Dr. Jianjiang Feng, Dr. Dongsun Park and Dr. Sook Yoon, as well as a number of anonymous reviewers

Activity related biometrics for person authentication

One of the major challenges in human-machine interaction has always been the development of such techniques that are able to provide accurate human recognition, so as to other either personalized services or to protect critical infrastructures from unauthorized access. To this direction, a series of well stated and efficient methods have been proposed mainly based on biometric characteristics of the user. Despite the significant progress that has been achieved recently, there are still many open issues in the area, concerning not only the performance of the systems but also the intrusiveness of the collecting methods. The current thesis deals with the investigation of novel, activity-related biometric traits and their potential for multiple and unobtrusive authentication based on the spatiotemporal analysis of human activities. In particular, it starts with an extensive bibliography review regarding the most important works in the area of biometrics, exhibiting and justifying in parallel the transition that is performed from the classic biometrics to the new concept of behavioural biometrics. Based on previous works related to the human physiology and human motion and motivated by the intuitive assumption that different body types and different characters would produce distinguishable, and thus, valuable for biometric verification, activity-related traits, a new type of biometrics, the so-called prehension biometrics (i.e. the combined movement of reaching, grasping activities), is introduced and thoroughly studied herein. The analysis is performed via the so-called Activity hyper-Surfaces that form a dynamic movement-related manifold for the extraction of a series of behavioural features. Thereafter, the focus is laid on the extraction of continuous soft biometric features and their efficient combination with state-of-the-art biometric approaches towards increased authentication performance and enhanced security in template storage via Soft biometric Keys. In this context, a novel and generic probabilistic framework is proposed that produces an enhanced matching probability based on the modelling of the systematic error induced during the estimation of the aforementioned soft biometrics and the efficient clustering of the soft biometric feature space. Next, an extensive experimental evaluation of the proposed methodologies follows that effectively illustrates the increased authentication potential of the prehension-related biometrics and the significant advances in the recognition performance by the probabilistic framework. In particular, the prehension biometrics related biometrics is applied on several databases of ~100 different subjects in total performing a great variety of movements. The carried out experiments simulate both episodic and multiple authentication scenarios, while contextual parameters, (i.e. the ergonomic-based quality factors of the human body) are also taken into account. Furthermore, the probabilistic framework for augmenting biometric recognition via soft biometrics is applied on top of two state-of-art biometric systems, i.e. a gait recognition (> 100 subjects)- and a 3D face recognition-based one (~55 subjects), exhibiting significant advances to their performance. The thesis is concluded with an in-depth discussion summarizing the major achievements of the current work, as well as some possible drawbacks and other open issues of the proposed approaches that could be addressed in future works.Open Acces

Horizontal asymmetries derived from script direction : consequences for attention and action

Tese apresentada para cumprimento dos requisitos necessários à obtenção do grau de Doutor em Psicologia na área de especialização de Psicologia Social apresentada no ISPA - Instituto Universitário, no ano de 2021.A direção de leitura e escrita estabelecem uma trajetória preferencial de exploração do espaço que é reforçada por diversas regularidades culturais consistentes com essa direccionalidade. A correlação espaço-movimento cria um esquema para a ação que enviesa a representação da agência humana, estendendo-se à representação de outros conceitos abstratos que não possuem bases sensoriomotoras. A dimensão horizontal é recrutada para melhor compreender estes conceitos, sendo ancorados de acordo com a direção de escrita e leitura da nossa língua. A assimetria espacial que esta direccionalidade induz constitui um contributo crucial para a área do embodiment, tendo sido demonstrado que afeta processos sociais e cognitivos. Contudo, os processos específicos que estas assimetrias ativam permanecem pouco explorados. Em sete estudos, esta dissertação investiga de que forma as assimetrias espaciais afetam inferências sociais e a performance visuo-motora para com estímulos ancorados na dimensão horizontal. O primeiro estudo indica que inferências sociais relacionadas com agência são preferencialmente atribuídas a faces de perfil orientadas para a direita (versus esquerda). Em duas experiências, o segundo estudo mostra que faces orientadas para a direita servem como pistas para a orientação de atenção. Faces orientadas para a direita, que traduzem a direção utilizada para representar a agência humana, facilitam a atenção para e deteção de alvos no campo visual direito, comparativamente a faces orientadas para a esquerda no campo visual esquerdo. No terceiro estudo, as faces foram substituídas por palavras temporais auditivas e visuais, que se sabe serem ancoradas horizontalmente. A assimetria espacial foi testada em duas experiências em comunidades com direções de leitura e escrita opostas (Português e Árabe). Observou-se uma ancoragem contrária do conceito abstrato ‘tempo’ entre as duas amostras (Português: passado-esquerda/futuro-direita; Árabe: passado-direita/futuro-esquerda). Adicionalmente, uma performance assimétrica reversa entre as duas comunidades linguísticas confirma que o mapeamento do tempo é enviesado pelos hábitos ortográficos e pela representação cultural da agência humana. Isto é, palavras temporais que coincidem com a direção induzida por ambos os sistemas de escrita (i.e., palavras relacionadas com futuro), dão origem a vantagem à direita na amostra Portuguesa, e vantagem à esquerda na amostra Árabe. O quarto estudo estendeu estes resultados à categoria da política, tipicamente representada através de coordenadas de esquerda e de direita. Respostas manuais e atencionais foram mais rápidas para alvos localizados à direita após terem sido apresentadas termos políticos de direita (versus alvos à esquerda após termos políticos de esquerda), que correspondiam à direção em que habitualmente se representa movimento. O quinto e último estudo demonstrou que a apresentação de palavras temporais simultaneamente com um tom auditivo não-espacial impede os efeitos de emergirem. Estas pistas bimodais revelaram as condições limitativas dos efeitos da assimetria espacial. Em conclusão, esta dissertação demonstra que existe uma propriedade genérica de movimento que deriva da direção ortográfica e que é transversal à representação de estímulos distintos, em várias tarefas e modalidades sensoriais. Estes resultados oferecem uma perspetiva mais abrangente sobre o impacto prevalente que uma característica da língua aparentemente irrelevante tem em processos cognitivos fundamentais de perceção, atenção, e julgamento.The directional activities of reading and writing have been shown to ground a preferential trajectory when scanning space. This horizontal directional formation is further reinforced by other cultural regularities that overlap with it. This space-movement correlation creates a left-right (or vice-versa) schema for action that biases the representation of human agency and extends to the representation of other abstract concepts lacking experiential sensorimotor bases. Consequently, the horizontal dimension is recruited to reason about abstract concepts that are mapped congruently with one’s dominant reading and writing or script direction. The spatial asymmetry that this combined directionality induces is a core finding in the embodiment area and has been shown to affect important social and cognitive processes. However, the specific processes activated by these asymmetries remain unclear. A series of seven experiments are outlined to investigate how spatial asymmetries affect social inferences and visuomotor performance to stimuli anchored in the horizontal dimension. The first study indicated that a range of agency-related social inferences are preferentially assigned to face profiles oriented rightward (versus leftward). Across two experiments, the second study showed that right oriented faces serve as attention-orienting primes. Rightward faces, which are in line with the direction used to represent human agency, facilitate attention to and detection of targets on the right hemifield, relative to leftward faces and targets on the left hemifield. In the third study, face primes were replaced by visual and auditory time words known to ground horizontally in space. Spatial asymmetries were tested in two experiments with communities holding opposite writing scripts (Portuguese and Arabic). We observed the mapping of time to be reversed between the two samples (Portuguese: past-left/future-right; Arabic: past-right/future-left). Further, a mirrored asymmetric performance between the two linguistic communities confirmed that the mapping of time is biased by orthographic habits and the cultural representation of human agency. That is, time words that coincide with the direction induced by both writing systems (i.e., future-related) gave rise to right-side advantage in the Portuguese sample and left-side advantage in the Arabic sample. The fourth study extended these results to the category of politics, commonly represented through coordinates of left and right. Manual and gaze responses were faster to targets embedded on the right following conservatism-related words (versus the left following socialism-related words) that embody the habitualized rightward movement direction. The fifth and final study demonstrated that presenting time words synchronously with an auditory nonspatial tone impaired cueing effects. These bimodal cues revealed the boundary conditions of the spatial agency bias. Overall, this dissertation underscores that a generic property of movement that is derived from orthographic direction underlies the representation of very distinct stimuli across tasks and sensory modalities. These findings offer a broader perspective on the pervasive impact a seemingly irrelevant feature of language has on fundamental cognitive processes of perception, attention, and judgment

The effects of DMT and associated psychedelics on the human mind and brain

This work presents seven investigations conducted with the aim to determine the effects of DMT (a compound which is able to cause remarkable effects in consciousness) and associated psychedelic drugs on the human brain and mind. Including a variety of neuroimaging (EEG, MEG and fMRI), phenomenological, psychometric and naturalistic research methods, these are the first controlled investigations of the impact of DMT in the human resting brain. Results revealed that DMT disrupted several brain mechanisms associated with top-down control (alpha power, integrity of high-level networks, modularity), increased measures related to entropy, or disorder (Lempel-Ziv complexity, novel pairwise connectivity) and immersive states of consciousness (delta/theta power), with some of these effects following the experiential trajectories of the DMT state. We also observed a significant temporal correlation between some of these effects (alpha power and default-mode network integrity fluctuations), which were supported by LSD effects of reduced feedback connectivity and neural adaption mechanisms. suggesting that the psychedelic brain state is one of reduced modularity, increased integration and functional plasticity. These findings were complemented by psychological studies showing that the DMT state is one of immersive visual imagery, intense somatic experiences and partial disconnection from the environment, which we found shared significant overlap with near- death experiences. DMT administration also resulted in positive mental health outcomes in healthy volunteers providing evidence for the first time that DMT may provide a useful alternative to currently- investigated psychedelic treatments. Finally, results from our last study performed in naturalistic environments revealed that psychedelics are able to have a transformative potential on core beliefs concerning the fundamental nature of reality and consciousness for up to 6 months, with important social and bioethical implications. Collectively these results attest to the strong impact that psychedelics have on varied human domains, which range experience, brain activity, mental health, intersubjectivity and beliefs.Open Acces