Rozprawy doktorskie: „Biometrics”

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Janečka, Petr. "Multimodální biometrický systém kombinující duhovku a sítnici". Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2015. http://www.nusl.cz/ntk/nusl-234910.

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This diploma thesis focuses on multibiometric systems, specifically on biometric fusion. The thesis describes eye biometrics, i.e. recognition based on retina and iris. The key part consists of design and implementation specification of a biometric system based on retina and iris recognition.

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Pereira, Tiago de Freitas 1985. "A comparative study of countermeasures to detect spoofing attacks in face authentication systems = Um estudo comparativo de contramedidas para detectar ataques de spoofing em sistemas de autenticação de faces". [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261478.

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Orientador: José Mario De Martino
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Abstract: The complete Abstract is available with the full electronic document.
Mestrado
Engenharia de Computação
Mestre em Engenharia Elétrica

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Hmani, Mohamed Amine. "Use of Biometrics for the Regeneration of Revocable Crypto-biometric Keys". Electronic Thesis or Diss., Institut polytechnique de Paris, 2022. http://www.theses.fr/2022IPPAS013.

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Ce travail de thèse vise à régénérer des clés crypto-biométriques (clés cryptographiques obtenues avec des données biométriques) résistantes aux méthodes de cryptanalyse quantique. Le défi est d'obtenir des clés avec une haute entropie pour avoir un haut niveau de sécurité, sachant que l'entropie contenue dans les références biométriques limite l'entropie de la clé. Notre choix a été d'exploiter la biométrie faciale.Nous avons d'abord créé un système de reconnaissance faciale de pointe basé en utilisant des bases de données publiques. Notre architecture utilise des réseaux de neurones profonds avec une fonction de perte‘Triplet loss'. Nous avons participé à deux Projets européens H2020 pour lesquelles nous avons fournit des adapations de notres systeme de reconnaise de visage. Nous avons également participé au challenge multimédia NIST SRE19 avec la version finale de notre système classique de reconnaissance faciale qui a donnée d'excellents résultats.Pour obtenir des clés crypto-biométriques, il est nécessaire de disposer de références biométriques binaires. Pour obtenir les représentations binaires directement à partir d'images de visage, nous avons proposé une méthode novatrice tirant parti des auto-encodeurs et la biométrie faciale classique précédemment mise en œuvre. Nous avons également exploité les représentations binaires pour créer un système de vérification de visage cancelable.Concernant notre objectif final, générer des clés crypto-biométriques, nous nous sommes concentrés sur les clés symétriques. Le chiffrement symétrique est menacé par l'algorithme Groover parce qu'il réduit la complexité d'une attaque par force brute de 2(N/2).. Pour atténuer le risque introduit par l'informatique quantique, nous devons augmenter la taille des clés. Pour cela, nous avons essayé de faire la représentation binaire plus longue et plus discriminante.Nous avons réussi à régénérer des clés crypto-biométriques de plus de 400 bits grâce à la qualité des plongements binaires. Les clés crypto-biométriques ont une haute entropie et résistent à la cryptanalyse quantique selon le PQCrypto projet car ils satisfont à l'exigence de longueur. Les clés sont régénérées à l'aide d'un schéma de "fuzzy commitment" en utilisant les codes BCH
This thesis aims to regenerate crypto-biometric keys (cryptographic keys obtained with biometric data) that are resistant to quantum cryptanalysis methods. The challenge is to obtain keys with high entropy to have a high level of security, knowing that the entropy contained in biometric references limits the entropy of the key. Our choice was to exploit facial biometrics.We first created a state-of-the-art face recognition system based on public frameworks and publicly available data based on DNN embedding extractor architecture and triplet loss function. We participated in two H2020 projects. For the SpeechXRays project, we provided implementations of classical and cancelable face biometrics. For the H2020 EMPATHIC project, we created a face verification REST API. We also participated in the NIST SRE19 multimedia challenge with the final version of our classical face recognition system.In order to obtain crypto-biometric keys, it is necessary to have binary biometric references. To obtain the binary representations directly from face images, we proposed an original method, leveraging autoencoders and the previously implemented classical face biometrics. We also exploited the binary representations to create a cancelable face verification system.Regarding our final goal, to generate crypto-biometric keys, we focused on symmetric keys. Symmetric encryption is threatened by the Groover algorithm because it reduces the complexity of a brute force attack on a symmetric key from 2N à 2(N/2). To mitigate the risk introduced by quantum computing, we need to increase the size of the keys. To this end, we tried to make the binary representation longer and more discriminative. For the keys to be resistant to quantum computing, they should have double the length.We succeeded in regenerating crypto-biometric keys longer than 400bits (with low false acceptance and false rejection rates) thanks to the quality of the binary embeddings. The crypto-biometric keys have high entropy and are resistant to quantum cryptanalysis, according to the PQCrypto project, as they satisfy the length requirement. The keys are regenerated using a fuzzy commitment scheme leveraging BCH codes

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Holeksa, David. "Návrh audio-vizuální databáze pro extrakci sekundárních biometrických a ne-biometrických znaků". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-220544.

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The aim of this semester project is to design a suitable database structure for the audio-visual data, parts extracted from the data corresponding to secondary biometric and non-biometric characteristics and description of these characters. The resulting database will be used for research into the identification of audio-visual content of multimedia data.

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Gancarčík, Lukáš. "Vicefaktorová autentizace elektronických dokumentů". Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2013. http://www.nusl.cz/ntk/nusl-224008.

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The aim of the thesis is to provide complete information regarding electronic documents and possibilities of their usage. The focus is concentrated on the area of authentication, which specifies the possibility of obtaining authentication information and describes the authentication processes itself. The diploma thesis also deals with the suggestion of multifactor authentication of electronic documents for the selected company.

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Samangooei, Sina. "Semantic biometrics". Thesis, University of Southampton, 2010. https://eprints.soton.ac.uk/153901/.

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Gait and face biometrics have a unique advantage in that they can be used when images are acquired at a distance and signals are at too low a resolution to be perceived by other biometrics. Given such situations, some traits can be difficult to extract automatically but can still be perceived semantically using human vision. It is contended that such semantic annotations are usable as soft biometric signatures, useful for identification tasks. Feature subset selection techniques are employed to compare the distinguishing ability of individual semantically described physical traits. Their identification ability is also explored, both in isolation and in the improvement of the recognition rates of some associated gait biometric signatures using fusion techniques. This is the first approach to explore semantic descriptions of physiological human traits as used alone or to complement primary biometric techniques to facilitate recognition and analysis of surveillance video. Potential traits to be described are explored and justified against their psychological and practical merits. A novel dataset of semantic annotations is gathered describing subjects in two existing biometric datasets. Two applications of these semantic features and their associated biometric signatures are explored using the data gathered. We also draw on our experiments as a whole to highlight those traits thought to be most useful in assisting biometric recognition overall. Effective analysis of surveillance data by humans relies on semantic retrieval of the data which has been enriched by semantic annotations. A manual annotation process is time-consuming and prone to error due to various factors. We explore the semantic content-based retrieval of surveillance captured subjects. Working under the premise that similarity of the chosen biometric signature implies similarity of certain semantic traits, a set of semantic retrieval experiments are performed using well established Latent Semantic Analysis techniques.

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Varadinov, Petr. "Účel a implementace snímání otisků prstů v osobních počítačích". Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-162689.

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This diploma thesis deals with fingerprint recognition applied in personal computers. The topic is analyzed both chronologically in historical context and in connection with other biometric methods. The thesis provides a comprehensive survey of the topic. It starts with physical layer, goes through hardware parts and ends with software architecture. A special attention is paid to programming fingerprint recognition support into end-user applications. These are the aims of the thesis: to place the silicon fingerprint sensing technology into the historical context and describe its evolution in connection with personal computers till the present times, to provide the results of market research of fingerprint sensors used in personal computers, to work out the summary of the functions the end-users have at their disposal, to present the market research results of fingerprint software, to work out the overview and the comparison of available software development kits (SDKs) and that of application programming interfaces (APIs) used for the described fingerprint sensor devices, and last but not least to develop a demonstration application that communicates with a fingerprint sensor device. Technical literature, market researches together with my own experience from the work in this field were used so as to meet the set aims. As for the demo application of this technology it is my own innovative approach. The thesis is divided into seven chapters where Chapter II -- Chapter VI directly deal with the mentioned topics. The completion of a missing angle of approach to the subject from end-users' and application programmers' perspective is the main asset of this thesis. The work also allows orientation on the silicon fingerprint sensor market and fingerprint software market. Moreover it shows possibilities how to extend this technology, it provides a detailed analysis of the software layer and presents programming samples showing that show how to use this technology. The demo application allowing audio volume control by a fingerprint device is an innovation in the branch of computer input devices.

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Ferreira, Iuri Emmanuel de Paula [UNESP]. "Delineamentos D-ótimos para os modelos de Michaelis-Menten e de Hill". Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/87920.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Os resultados de muitos experimentos em áreas da biologia, como a farmacologia, a bioquímica e a agronomia, geralmente são analisados por ajustes de modelos não-lineares através dos quais pretende-se explicar a resposta através dos fatores pré-especificados no experimento. As estimações dos parâmetros ou das funções de interesse podem ser imprecisas se os níveis dos fatores não forem adequadamente escolhidos, impossibilitando ao pesquisador a obtenção da informação desejada sobre o objeto de estudo. A construção de um delineamento ótimo, que maximize a informação sobre algum aspecto de interesse, é crucial para o sucesso da prática experimental. O objetivo deste trabalho foi a obtenção de delineamentos D-ótimos exatos para modelos não-lineares utilizados para estudar cinética enzimática e transporte de minerais no organismo, como o de Michaelis-Menten e o de RiU. Para este fim, duas abordagens foram consideradas, a saber, a de delineamentos localmente ótimos e a pseudo-Bayesiana. Com o auxílio dos algoritmos genético e exchange foi possível obter delineamentos D-ótimos exatos para o modelo de Michaelis-Menten, para o modelo de RiU e para ambos, considerando-se valores diferentes e distribuições com diversos coeficientes de variação como informação a priori
The results of many experiments in biological fields, as pharmacology, biochemistry and agriculture, usually are analyzed by fitting nonlinear models, which are supposed to describe well the resp'onse to the pre-specified factors in the experiment. The estimates of the parameters or of their functions of interest could be imprecise if the factor levels are not adequately chosen. The construction of an optimum design, which maximizes the information about some aspect of interest, is crucial for the success of the experimental practice. The aim of this work was constructing exact D-optimal designs for nonlinear models usually used in studies of enzyme kinetics and mineral transport in organisms, such as the Michaelis-Menten and RiU models. Two approaches were considered, the locally optimal and pseudo- Bayesian designs. Genetic and Exchange algorithms were used for getting exact designs aiming at the Michaelis-Menten model, aiming at the RiU model, each one separately, and aiming at both models when considering a composite criterion. Different values and probability distributions with several variation coefficients were considered as prior information

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Martins, Andréa Camila dos Santos [UNESP]. "O método de pontos interiores no planejamento da radioterapia". Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/95056.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Um tratamento do câncer por radioterapia tem como objetivo a eliminação das células do tumor e preservação das células saudáveis, obtendo assim uma melhor homo-geneização da dose administrada e menor possibilidade de complicações clínicas durante o tratamento. O sucesso do tratamento depende de um bom planejamento. Para um planejamento ótimo, técnicas matemáticas estão sendo utilizadas com o objetivo de maximizar a radiação no tumor e minimizar a radiação nas regiões vizinhas, com isto modelos de programação linear têm sido ótimas ferramentas para auxiliar a construção dos planos de tratamento por radioterapia. Assim, este trabalho visa: estudar os principais conceitos envolvidos no planejamento do tratamento do câncer por radioterapia; estudar modelos de programação linear (PL) aplicados ao planejamento ótimo; fazer um amplo estudo sobre a técnica de pontos interiores para PL e apresentar uma aplicação desta técnica para resolução de um problema de planejamento ótimo para o tratamento do câncer por radioterapia
A cancer treatment by radiotherapy aims to eliminate tumor cells and preservation of healthy cells, thus getting a better homogenization of the administered dose and fewer chances of complications during treatment. Treatment success depends on good planning. For an optimal planning, mathematical techniques are being used in order to maximize radiation at tumor and minimize radiation in the surrounding regions, thus linear programming models has been great tools to assist the construction of treatment plans for radiation therapy. Thus, this work aims: studying the key concepts involved in planning the treatment of cancer by radiotherapy; study the models the linear program- ming (PL) applied to optimal planning; make a broad study on the technique of interior point for PL and present an enforcement of this technique for solving a problem of optimal planning for cancer treatment by radiotherapy

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Brobeck, Stefan, i Tobias Folkman. "Biometrics : Attitudes and factors influencing a breakthrough in Sweden". Thesis, Jönköping University, JIBS, Business Informatics, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-148.

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Biometrics is a collection of methods for identifying and authorizing individuals with something they are, or do. It is considered to be one of the most secure technologies for security, both physical and logical. Security is something very important for organizations today, but yet there has been a low interest in investing in biometrics for security in Sweden.

The purpose of this thesis has been to establish factors to why biometrics has not been implementedto any large extent, even though the technology has been around for long. We have evaluated the attitudes and views of individuals, as well as company leaders. Problem and questions with biometrics that often are discussed are privacy concerns, costs and ROI (return on investment) and user acceptance. Foremost there is a concern about the costs of implementing such a solution, although some claim that money can be saved by avoiding the costs in more traditional security methods, such as password administration and in security cards.

There is a range of different technologies to use, such as facial-scan, voice-scan and the most mature and well known technique, finger-scan which has been around for a long time, especially for identifying criminals. All these techniques have there positive and negative sides, often measured in different levels of universality, uniqueness, permanence and collectability, e.g. eye-scan has a high uniqueness, facial-scan has a high universability and signature-scan has a low permanence level.

We have collected our data through interviews with companies and suppliers of biometric systems as well as a questionnaire given to private persons. By interpreting the data in a qualitative way we have made our analysis and reached a conclusion.

Our result shows that a cost related to biometric solutions is the largest reason why investments have been absent. This verifies the results of other authors, that the cost is the largest obstacle. Another important factor is that companies believe that biometrics is for organizations with a very high security need. Further our result show that individuals are positive towards biometrics.

Biometri är ett samlingsnamn för tekniker som identifierar och auktoriserar individer, antingen något de är eller gör. Biometri anses vara en av de säkraste teknologierna för säkerhet, både fysisk och logisk. Säkerhet är något som är mycket viktigt för organisationer i dagens läge, men än så länge så har investeringar i biometriska säkerhetslösningar i Sverige uteblivit. Syftet med denna magisteruppsats har varit att fastställa faktorer som bidrar till att biometriska lösningar inte har blivit implementerade i någon större utsträckning, trots att teknologin har funnits länge. Vi har utvärderat individers samt företagsledares attityder och synsätt angående biometri.

Frågor och problem som ofta relateras till biometri är personligintegritet, kostnader och avkastning på investering samt användaracceptans. Framförallt är det osäkerheten kring kostnaderna av en implementering av en biometrisklösning. Det finns även de som hävdar att biometriska lösningar kan spara pengar jämfört med traditionella system därför att man undviker till exempel lösenordsadministration och passerkort.

Det finns en rad olika tekniker att använda, exempelvis ansiktsavläsning, röstigenkänning och den mest mogna och kända tekniken, fingeravtrycksläsning som har existerat en längre tid, framförallt för att identifiera kriminella. Det finns positiva och negativa sidor med alla dessa tekniker, de mäts oftast i olika nivåer av hur många som kan använda det, hur unikt biometrin är, beständighet och hur biometrin samlas in.

Genom intervjuer med företag och leverantörer av biometriska lösningar samt en utdelad enkät till privat personer har vi samlat in data. Vi har sedan tolkat data kvalitativt och utfört vår analys och slutligen kommit fram till ett resultat.

Vårt resultat har visat att kostnader relaterade till biometriska system är det största skälet till varför investeringar har uteblivit. Detta bekräftar vad många andra författare tidigare har funnit, att kostnaderna är det största hindret. En annan viktig faktor är att företag anser att biometri är något för verksamheter som kräver den allra högsta säkerheten. Vidare har individer en positiv inställning till biometri.

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Fouad, Marwa. "Towards Template Security for Iris-based Biometric Systems". Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/22736.

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Personal identity refers to a set of attributes (e.g., name, social insurance number, etc.) that are associated with a person. Identity management is the process of creating, maintaining and destroying identities of individuals in a population. Biometric technologies are technologies developed to use statistical analysis of an individual’s biological or behavioral traits to determine his identity. Biometrics based authentication systems offer a reliable solution for identity management, because of their uniqueness, relative stability over time and security (among other reasons). Public acceptance of biometric systems will depend on their ability to ensure robustness, accuracy and security. Although robustness and accuracy of such systems are rapidly improving, there still remain some issues of security and balancing it with privacy. While the uniqueness of biometric traits offers a convenient and reliable means of identification, it also poses the risk of unauthorized cross-referencing among databases using the same biometric trait. There is also a high risk in case of a biometric database being compromised, since it’s not possible to revoke the biometric trait and re-issue a new one as is the case with passwords and smart keys. This unique attribute of biometric based authentication system poses a challenge that might slow down public acceptance and the use of biometrics for authentication purposes in large scale applications. In this research we investigate the vulnerabilities of biometric systems focusing on template security in iris-based biometric recognition systems. The iris has been well studied for authentication purposes and has been proven accurate in large scale applications in several airports and border crossings around the world. The most widely accepted iris recognition systems are based on Daugman’s model that creates a binary iris template. In this research we develop different systems using watermarking, bio-cryptography as well as feature transformation to achieve revocability and security of binary templates in iris based biometric authentication systems, while maintaining the performance that enables widespread application of these systems. All algorithms developed in this research are applicable on already existing biometric authentication systems and do not require redesign of these existing, well established iris-based authentication systems that use binary templates.

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Santos, Maurício Bedim dos [UNESP]. "Delineamentos ótimos para experimentos farmacocinéticos". Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/87911.

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Os ensaios na area de farmacologia cl nica envolvem coletas sangu neas e medidas da informação (concentração de um fármaco) em horários pré estabelecidos. A prática atual, na maioria das vezes, estabelece os tempos de coleta arbitrariamente, o que pode resultar em dados pouco informativos para ajustar um modelo. Uma metodologia para resolver este tipo de problema e a construcão de delineamentos otimos. Em geral, os modelos envolvem equações não lineares. Sendo que um modelo popular e o modelo monocompartimental (de primeira ordem de absorção e eliminação) que possui três parâmetros. O problema principal de delineamento para modelos não lineares e que a matriz de variâncias e covariâncias dos estimadores dos parâmetros depende dos valores destes, dificultando o planejamento. Outra dificuldade é que várias coletas são realizadas num mesmo sujeito e portanto as respostas são correlacionadas. Assim, a matriz de variâncias e covariâncias depende também das correlações que podem ser incorporadas considerando-se um modelo não linear com efeitos aleatórios. Esse trabalho visa o estudo da teoria de delineamentos...
Trials in clinical pharmacology involves colleting blood samples and measuring the concentration of a drug at pre-especi ed moments. Current practice, usually xes the point times arbitrarily, which can result in uninformative data to t the aimed model. A methodology for solving such problems is the construction of optimum designs. In general, the models involve nonlinear equations. A popular model is the one-compartment model ( rst-order absorption and elimination). This model has three parameters. The main problem of design for nonlinear models is that the matrix of variances and covariances of the estimators of the parameters depends on the values of these, making the planning more di cult. Another di culty is that several samples are performed in the same subject and therefore the responses are correlated. The matrix of variances and covariances also depends on the correlations. The correlations can be incorporated by considering a nonlinear model with random e ects. This work aims to study the theory of optimal designs and the construction of algorithm to optimize designs under the nonlinear model with xed e ects and random e ects. The methodology can produce local optimum designs at some prior value of the parameters or try to reach global optimum through the incorporation of probability distributions of the parameters which are taken into account when calculating the value of the criterion used such designs are called Bayesians. Based on the results of an experiment from the literature D and Aw local and Bayesian optimum designs were obtained. To compare designs their e ciencies were calculated

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Ferreira, Iuri Emmanuel de Paula. "Delineamentos D-ótimos para os modelos de Michaelis-Menten e de Hill /". Botucatu : [s.n.], 2010. http://hdl.handle.net/11449/87920.

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Orientador: Luzia Aparecida Trinca
Banca: Cláudia Pio Ferreira
Banca: Silvio Sandoval Zocchi
Banca: Miriam Harumi Tsunemi
Banca: Julia Maria Pavan Soler
Resumo: Os resultados de muitos experimentos em áreas da biologia, como a farmacologia, a bioquímica e a agronomia, geralmente são analisados por ajustes de modelos não-lineares através dos quais pretende-se explicar a resposta através dos fatores pré-especificados no experimento. As estimações dos parâmetros ou das funções de interesse podem ser imprecisas se os níveis dos fatores não forem adequadamente escolhidos, impossibilitando ao pesquisador a obtenção da informação desejada sobre o objeto de estudo. A construção de um delineamento ótimo, que maximize a informação sobre algum aspecto de interesse, é crucial para o sucesso da prática experimental. O objetivo deste trabalho foi a obtenção de delineamentos D-ótimos exatos para modelos não-lineares utilizados para estudar cinética enzimática e transporte de minerais no organismo, como o de Michaelis-Menten e o de RiU. Para este fim, duas abordagens foram consideradas, a saber, a de delineamentos localmente ótimos e a pseudo-Bayesiana. Com o auxílio dos algoritmos genético e exchange foi possível obter delineamentos D-ótimos exatos para o modelo de Michaelis-Menten, para o modelo de RiU e para ambos, considerando-se valores diferentes e distribuições com diversos coeficientes de variação como informação a priori
Abstract: The results of many experiments in biological fields, as pharmacology, biochemistry and agriculture, usually are analyzed by fitting nonlinear models, which are supposed to describe well the resp'onse to the pre-specified factors in the experiment. The estimates of the parameters or of their functions of interest could be imprecise if the factor levels are not adequately chosen. The construction of an optimum design, which maximizes the information about some aspect of interest, is crucial for the success of the experimental practice. The aim of this work was constructing exact D-optimal designs for nonlinear models usually used in studies of enzyme kinetics and mineral transport in organisms, such as the Michaelis-Menten and RiU models. Two approaches were considered, the locally optimal and pseudo- Bayesian designs. Genetic and Exchange algorithms were used for getting exact designs aiming at the Michaelis-Menten model, aiming at the RiU model, each one separately, and aiming at both models when considering a composite criterion. Different values and probability distributions with several variation coefficients were considered as prior information
Mestre

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Martins, Andréa Camila dos Santos. "O método de pontos interiores no planejamento da radioterapia /". Botucatu : [s.n.], 2011. http://hdl.handle.net/11449/95056.

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Orientador: Helenice de Oliveira Florentino Silva
Banca: Andréa Carla Gonçalves Vianna
Banca: Antônio Roberto Balbo
Resumo: Um tratamento do câncer por radioterapia tem como objetivo a eliminação das células do tumor e preservação das células saudáveis, obtendo assim uma melhor homo-geneização da dose administrada e menor possibilidade de complicações clínicas durante o tratamento. O sucesso do tratamento depende de um bom planejamento. Para um planejamento ótimo, técnicas matemáticas estão sendo utilizadas com o objetivo de maximizar a radiação no tumor e minimizar a radiação nas regiões vizinhas, com isto modelos de programação linear têm sido ótimas ferramentas para auxiliar a construção dos planos de tratamento por radioterapia. Assim, este trabalho visa: estudar os principais conceitos envolvidos no planejamento do tratamento do câncer por radioterapia; estudar modelos de programação linear (PL) aplicados ao planejamento ótimo; fazer um amplo estudo sobre a técnica de pontos interiores para PL e apresentar uma aplicação desta técnica para resolução de um problema de planejamento ótimo para o tratamento do câncer por radioterapia
Abstract: A cancer treatment by radiotherapy aims to eliminate tumor cells and preservation of healthy cells, thus getting a better homogenization of the administered dose and fewer chances of complications during treatment. Treatment success depends on good planning. For an optimal planning, mathematical techniques are being used in order to maximize radiation at tumor and minimize radiation in the surrounding regions, thus linear programming models has been great tools to assist the construction of treatment plans for radiation therapy. Thus, this work aims: studying the key concepts involved in planning the treatment of cancer by radiotherapy; study the models the linear program- ming (PL) applied to optimal planning; make a broad study on the technique of interior point for PL and present an enforcement of this technique for solving a problem of optimal planning for cancer treatment by radiotherapy
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Goswani, B. "Lip-based behavioural biometrics". Thesis, University of Surrey, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.533201.

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Vala, Hiralba. "Facial biometrics for forensics". Thesis, Vala, Hiralba (2021) Facial biometrics for forensics. Masters by Coursework thesis, Murdoch University, 2021. https://researchrepository.murdoch.edu.au/id/eprint/63402/.

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Facial biometrics works by verifying and identifying a person based on behavior and physical behavior. Biometric plays a significant role in today's safety environment. Face recognition technology stems from the use of providing secure access to Smartphones, identifying criminal suspects to identify criminal suspects from photographs considered as a tool of the justice system. Recently, facial biometrics have been added to this list and introduced one of the safest ways to verify authenticity. The techniques and methods of face biometrics are a face-to-face comparison system that verifies facial features Among the growing availability of observational evidence and expert comparisons based on experts is considered court approval, which ensures its effectiveness is very important. Face comparisons are often performed using morphological analysis (MA), a highly based method of the untested feature. Face recognition has become an important and common tool used by crime investigators. Compared with automatic facial recognition, forensic facial recognition is more demanding because it has to be able to handle images taken under adverse conditions and has a greater responsibility to follow legal procedures. Such systems assist users in collecting and analyzing biometric data, and support decision-making by human behavior pattern and / or validation. The challenges and future trends of conventional in-depth learning methods are described in detail to assist the researcher. In addition, traditional and in-depth learning methods of various body-based systems are analyzed for evaluation. Advances in forensic facial recognition by research on facial aging, facial recognition, sketch recognition, face recognition in video, infrared proximity, and the use of soft biometrics will be discussed. Other studies examining facial comparisons have shown low accuracy and reliability in a variety of situations. This can happen with printed images, electronic images, and even similar appearance. A number of issues are related to court approval and the credibility of the system. To date, there is no application available that automatically compares the suspect's image with the mug shot database and gives a result that can be used in court. The fact that biometric face recognition in most cases can be used for forensic purposes is true but issues related to the integration of technology and the legal system of the court are still being resolved. There is a great need for research that is multidisciplinary in nature and that will integrate face recognition technology with existing legal systems.

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Mikaelyan, Anna. "Compact orientation and frequency estimation with applications in biometrics : Biometrics on the orientation express". Doctoral thesis, Högskolan i Halmstad, CAISR Centrum för tillämpade intelligenta system (IS-lab), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-28205.

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Automatic feature extraction still remains a relevant image and signal processing problem even tough both the field and technologies are developing rapidly. Images of low quality, where it is extremely difficult to reliably process image information automatically, are of special interest. To such images we can refer forensic fingerprints, which are left unintentionally on different surfaces andare contaminated by several of the most difficult noise types. For this reason, identification of fingerprints is mainly based on the visual skills of forensic examiners. We address the problem caused by low quality in fingerprints by connecting different sources of information together, yielding dense frequency and orientation maps in an iterative scheme. This scheme comprises smoothing ofthe original, but only along, ideally never across, the ridges. Reliable estimation of dense maps allows to introduce a continuous fingerprint ridge counting technique. In fingerprint scenario the collection of irrefutable tiny details, e.g. bifurcation of ridges, called minutiae, is used to tie the pattern of such points and their tangential directions to the finger producing the pattern. This limited feature set, location and direction of minutiae, is used in current AFIS systems, while fingerprint examiners use the extended set of features, including the image information between the points. With reasonably accurate estimationsof dense frequency and orientation maps at hand, we have been able to propose a novel compact feature descriptor of arbitrary points. We have used these descriptors to show that the image information between minutiae can be extracted automatically and be valuable for identity establishment of forensic images even if the underlying images are noisy. We collect and compress the image information in the neighborhoods of the fine details, such as minutiae, to vectors, one per minutia, and use the vectors to "color" the minutiae. When matching two patterns (of minutiae) even the color of the minutia must match to conclude that they come from the same identity. This feature development has been concentrated and tested on forensic fingerprint images. However, we have also studied an extension of its application area to other biometrics, periocular regions of faces. This allowed us to test the persistence of automatically extracted features across different types of imagesand image qualities, supporting its generalizability.

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Pisani, Paulo Henrique. "Biometrics in a data stream context". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-08052017-141153/.

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The growing presence of the Internet in day-to-day tasks, along with the evolution of computational systems, contributed to increase data exposure. This scenario highlights the need for safer user authentication systems. An alternative to deal with this is by the use of biometric systems. However, biometric features may change over time, an issue that can affect the recognition performance due to an outdated biometric reference. This effect can be called as template ageing in the area of biometrics and as concept drift in machine learning. It raises the need to automatically adapt the biometric reference over time, a task performed by adaptive biometric systems. This thesis studied adaptive biometric systems considering biometrics in a data stream context. In this context, the test is performed on a biometric data stream, in which the query samples are presented one after another to the biometric system. An adaptive biometric system then has to classify each query and adapt the biometric reference. The decision to perform the adaptation is taken by the biometric system. Among the biometric modalities, this thesis focused on behavioural biometrics, particularly on keystroke dynamics and on accelerometer biometrics. Behavioural modalities tend to be subject to faster changes over time than physical modalities. Nevertheless, there were few studies dealing with adaptive biometric systems for behavioural modalities, highlighting a gap to be explored. Throughout the thesis, several aspects to enhance the design of adaptive biometric systems for behavioural modalities in a data stream context were discussed: proposal of adaptation strategies for the immune-based classification algorithm Self-Detector, combination of genuine and impostor models in the Enhanced Template Update framework and application of score normalization to adaptive biometric systems. Based on the investigation of these aspects, it was observed that the best choice for each studied aspect of the adaptive biometric systems can be different depending on the dataset and, furthermore, depending on the users in the dataset. The different user characteristics, including the way that the biometric features change over time, suggests that adaptation strategies should be chosen per user. This motivated the proposal of a modular adaptive biometric system, named ModBioS, which can choose each of these aspects per user. ModBioS is capable of generalizing several baselines and proposals into a single modular framework, along with the possibility of assigning different adaptation strategies per user. Experimental results showed that the modular adaptive biometric system can outperform several baseline systems, while opening a number of new opportunities for future work.
A crescente presença da Internet nas tarefas do dia a dia, juntamente com a evolução dos sistemas computacionais, contribuiu para aumentar a exposição dos dados. Esse cenário evidencia a necessidade de sistemas de autenticação de usuários mais seguros. Uma alternativa para lidar com isso é pelo uso de sistemas biométricos. Contudo, características biométricas podem mudar com o tempo, o que pode afetar o desempenho de reconhecimento devido a uma referência biométrica desatualizada. Esse efeito pode ser chamado de template ageing na área de sistemas biométricos adaptativos ou de mudança de conceito em aprendizado de máquina. Isso levanta a necessidade de adaptar automaticamente a referência biométrica com o tempo, uma tarefa executada por sistemas biométricos adaptativos. Esta tese estudou sistemas biométricos adaptativos considerando biometria em um contexto de fluxo de dados. Neste contexto, o teste é executado em um fluxo de dados biométrico, em que as amostras de consulta são apresentadas uma após a outra para o sistema biométrico. Um sistema biométrico adaptativo deve então classificar cada consulta e adaptar a referência biométrica. A decisão de executar a adaptação é tomada pelo sistema biométrico. Dentre as modalidades biométricas, esta tese foca em biometria comportamental, em particular em dinâmica da digitação e em biometria por acelerômetro. Modalidades comportamentais tendem a ser sujeitas a mudanças mais rápidas do que modalidades físicas. Entretanto, havia poucos estudos lidando com sistemas biométricos adaptativos para modalidades comportamentais, destacando uma lacuna para ser explorada. Ao longo da tese, diversos aspectos para aprimorar o projeto de sistemas biométricos adaptativos para modalidades comportamentais em um contexto de fluxo de dados foram discutidos: proposta de estratégias de adaptação para o algoritmo de classificação imunológico Self-Detector, combinação de modelos genuíno e impostor no framework do Enhanced Template Update e aplicação de normalização de scores em sistemas biométricos adaptativos. Com base na investigação desses aspectos, foi observado que a melhor escolha para cada aspecto estudado dos sistemas biométricos adaptativos pode ser diferente dependendo do conjunto de dados e, além disso, dependendo dos usuários no conjunto de dados. As diferentes características dos usuários, incluindo a forma como as características biométricas mudam com o tempo, sugerem que as estratégias de adaptação deveriam ser escolhidas por usuário. Isso motivou a proposta de um sistema biométrico adaptativo modular, chamado ModBioS, que pode escolher cada um desses aspectos por usuário. O ModBioS é capaz de generalizar diversos sistemas baseline e propostas apresentadas nesta tese em um framework modular, juntamente com a possibilidade de atribuir estratégias de adaptação diferentes por usuário. Resultados experimentais mostraram que o sistema biométrico adaptativo modular pode superar diversos sistemas baseline, enquanto que abre um grande número de oportunidades para trabalhos futuros.

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Gibavičius, Darius. "Genetinių algoritmų taikymas biometrijoje". Master's thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100617_141716-09318.

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Baigiamajame magistro darbe nagrinėjamas genetinių algoritmų taikymas biometrijoje. Išnagrinėta plačiausiai naudojama biometrinė informacija, aprašytos labiausiai paplitusios biometrinės sistemos, genetiniai algoritmai bei jų pritaikymas biometrinių sistemų optimizavimui. Baigiamajame darbe pasiūlytas naujas rankos atpažinimo metodas. Šiam metodui pritaikyti genetiniai algoritmai. Darbą sudaro 7 dalys: įvadas, biometrija, genetiniai algoritmai, genetinių algoritmų taikymas biometrinėse sistemose, genetinių algoritmų taikymas rankos atpažinimui, išvados ir literatūra. Darbo apimtis – 51 p. teksto be priedų, 30 pav., 4 lent., 32 bibliografiniai šaltiniai.
In the graduation thesis to receive the master‘s degree the application of genetic algorithms in biometrics is analysed. The most widely used biometric information have been examined, the most common biometric systems, genetic algorithms and their customization in biometric systems optimization have been described. A new method is proposed for hand recognition. Genetic algorithms have been customized for this method. Structure: introduction, biometry, genetic algorithms, application of genetic algorithms in biometric systems, application of genetic algorithms for hand recognition, the conclusions and bibliography. Thesis consist of: 51 p. text without appendixes, 30 pictures, 4 tables, 32 bibliographical entries.

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Kodaira, Juliana Yukari [UNESP]. "Uma abordagem probabilística do número de reprodução básica em modelos epidemiológicos com aplicação na ferrugem do eucalipto". Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/87914.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Na epidemiologia matemática, uma importante medida derivada do modelo determinístico associado à dinâmica de transmissão de uma doença infecciosa é o número esperado de infecções secundárias produzidas por um caso indexado em uma população completamente suscetível, conhecido como número de reprodução básica R0. Utilizando simulações de Monte Carlo, estudamos o efeito da incerteza sobre R0 em modelos compartimentos de transmissão de doenças, associando variáveis aleatórias uniformemente distribuídas a cada parâmetro constituinte de R0. Esta pertubação sobre os parâmetros corresponde à imprecisão intrínseca de seus valores na natureza. Neste trabalho também consideramos diferentes intervalos para as taxas de transmissão de doença com o intuito de avaliar seus efeitos dinâmicos. Aplicamos este método à modelagem da ferrugem do eucalipto, que é uma doença muito comum e severa em plantações de Eucalyptus spp. e outras mirtáceas, transmitida pelo fungo Puccinia psidii Winter. Hoje o eucalipto possui importância significativa tanto no mercado nacional quanto internacional e, portanto, iniciativas que auxiliem seu manejo integrado de doenças são imprescindíveis. Nossos resultados mostram que o método utilizado é eficiente, pois representa a influência das taxas de transmissão de doença no padrão da distribuição de probabilidade aproximada de R0, permitindo a obtenção das funções empíricas percentílicas complementares para os modelos considerados
In mathematical epidemiology, an important measure derived from the deterministic model associated with the transmission dynamics of an infectious disease is the expected number of secondary infections produced by an indexed case in a completely susceptible population, known as the basic reproduction number R0. Using Monte Carlo simulations, we studied the effect of the uncertainty on R0 in compartmental disease transmission models, associating random variables uniformly distributed to each constituent parameter of R0. This perturbation on the parameters correspond to the intrinsic imprecision of their values in nature. In this work we also consider different ranges for the disease transmission rates in order to evaluate their dynamical effects. We apply this method to the eucalyptus rust, which is a very common and severe disease in plantations of Eucalyptus spp. and others Myrtaceae, transmitted by the fungus Puccinia psidii Winter. Today, eucalyptus has significant importance in both national and international market. Therefore, initiatives to help its integrated disease management are essential. Our results show that the method is efficient, since it represents the influence of the disease transmission rates in the approximated probability distribution pattern of R0, allowing us to obtain the empirical percentile complementary functions for the considered models

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Canuto, Jânio Coutinho. "Eficiência da análise multifractal na verificação de assinaturas dinâmicas". [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259415.

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Orientador: Lee Luan Ling
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: A verificação de identidades de forma confiável é cada vez mais necessária em nossa sociedade amplamente interconectada. Nesse contexto, a verificação biométrica é uma proposta alternativa, e mais segura, aos métodos tradicionalmente utilizados, como senhas e cartões. A análise multifractal, por sua vez, tem sido usada com sucesso em diversas aplicações de processamento de sinais, além disso, diversos estudos mostram a presença de características multifractais em processos naturais. Este trabalho tem como objetivo analisar os sinais referentes às assinaturas dinâmicas, provenientes de equipamentos como PDAs e tablet-pcs, sob o prisma da teoria multifractal. É estudada a capacidade de discriminação da característica multifractal na detecção de falsificações de assinaturas, tanto quando usadas isoladamente quanto em conjunto com características tradicionais, num contexto de fusão de informação, com resultados equivalentes ao estado da arte deste tema. Além disso, é realizada uma quantificação, através da teoria da informação, desta capacidade discriminatória. Por fim, é apresentada uma aplicação alternativa da informação multifractal no contexto da biometria: a análise de qualidade das amostras
Abstract: Reliable identity verification is an increasing necessity in our largely networked society. On this topic, biometric verification is a safer alternative to the traditional methods, such as passwords and ID cards. On the other hand, multifractal analysis has been successfully used in a wide range of signal processing applications; moreover, many works show the occurrence of multifractal traits on biological processes. This work aims at analyzing dynamic signature signals collected through devices such as PDAs and tablet-pcs, from a multifractal perspective. A study of the multifractal features discriminative capabilities on signature forgery detection is realized on two scenarios: when it is the unique feature used by the system, and in tandem with traditional features on an information fusion scheme; with results as good as those found in the state of the art of this area. Furthermore, an information theoretic quantification of the discrimination capability is realized. Finally, an alternative application for such features is presented: the evaluation of samples quality
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica

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Santos, Maurício Bedim dos. "Delineamentos ótimos para experimentos farmacocinéticos /". Botucatu : [s.n.], 2010. http://hdl.handle.net/11449/87911.

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Orientador: Luiza Aparecida Trinca
Banca: José Silvio Govone
Banca: Silvio Sandoval Zocchi
Resumo: Os ensaios na area de farmacologia cl nica envolvem coletas sangu neas e medidas da informação (concentração de um fármaco) em horários pré estabelecidos. A prática atual, na maioria das vezes, estabelece os tempos de coleta arbitrariamente, o que pode resultar em dados pouco informativos para ajustar um modelo. Uma metodologia para resolver este tipo de problema e a construcão de delineamentos otimos. Em geral, os modelos envolvem equações não lineares. Sendo que um modelo popular e o modelo monocompartimental (de primeira ordem de absorção e eliminação) que possui três parâmetros. O problema principal de delineamento para modelos não lineares e que a matriz de variâncias e covariâncias dos estimadores dos parâmetros depende dos valores destes, dificultando o planejamento. Outra dificuldade é que várias coletas são realizadas num mesmo sujeito e portanto as respostas são correlacionadas. Assim, a matriz de variâncias e covariâncias depende também das correlações que podem ser incorporadas considerando-se um modelo não linear com efeitos aleatórios. Esse trabalho visa o estudo da teoria de delineamentos... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Trials in clinical pharmacology involves colleting blood samples and measuring the concentration of a drug at pre-especi ed moments. Current practice, usually xes the point times arbitrarily, which can result in uninformative data to t the aimed model. A methodology for solving such problems is the construction of optimum designs. In general, the models involve nonlinear equations. A popular model is the one-compartment model ( rst-order absorption and elimination). This model has three parameters. The main problem of design for nonlinear models is that the matrix of variances and covariances of the estimators of the parameters depends on the values of these, making the planning more di cult. Another di culty is that several samples are performed in the same subject and therefore the responses are correlated. The matrix of variances and covariances also depends on the correlations. The correlations can be incorporated by considering a nonlinear model with random e ects. This work aims to study the theory of optimal designs and the construction of algorithm to optimize designs under the nonlinear model with xed e ects and random e ects. The methodology can produce local optimum designs at some prior value of the parameters or try to reach global optimum through the incorporation of probability distributions of the parameters which are taken into account when calculating the value of the criterion used such designs are called Bayesians. Based on the results of an experiment from the literature D and Aw local and Bayesian optimum designs were obtained. To compare designs their e ciencies were calculated
Mestre

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Zahidi, Salman. "Biometrics - Evaluation of Current Situation". Thesis, Linköpings universitet, Informationskodning, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-73230.

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Information security has always been a topic of concern in the world as an emphasis on new techniques to secure the identity of a legitimate user is regarded as top priority. To counter such an issue, we have a traditional way of authentication factors “what you have” and “what you know” in the form of smart cards or passwords respectively. But biometrics is based on the factor “who are you” by analyzing human physical or behavioral characteristics. Biometrics has always been an efficient way of authorization and is now considered as a $1500 million industry where fingerprints dominate the biometrics while iris is quickly emerging as the most desirable form of biometric technique.The main goal of this thesis is to compare and evaluate different biometrics techniques in terms of their purpose, recognition mechanism, market value and their application areas. Since there are no defined evaluating criteria, my method of evaluation was based on a literature survey from internet, books, IEEE papers and technical surveys. Chapter 3 is focused on different biometrics techniques where I discuss them briefly but in chapter 4, I go deeper into Iris, fingerprints, facial techniques which are prominent in biometrics world. Lastly, I had a general assessment of the biometrics, their future growth and suggested specific techniques for different environment like access controls, e-commerce, national ids, and surveillance.

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Reid, Daniel. "Human identification using soft biometrics". Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/352293/.

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Humans naturally use descriptions to verbally convey the appearance of an individual. Eyewitness descriptions are an important resource for many criminal investigations. However, they cannot be used to automatically search databases featuring video or biometric data - reducing the utility of human descriptions in the search for the suspect. Soft biometrics are a new form of biometric identification which uses physical or behavioural traits that can be naturally described by humans. This thesis will explore how soft biometrics can be used alongside traditional biometrics, allowing video footage and biometric data to be searched using a description. To permit soft biometric identification the human description must be accurate, yet conventional descriptions comprising of absolute labels and estimations are often unreliable. A novel method of obtaining human descriptions will be introduced which utilizes comparative categorical labels to describe the differences between subjects. A database of facial and bodily comparative labels is introduced and analysed. Prior to use as a biometric feature, comparative descriptions must be anchored. Several techniques to convert multiple comparative labels into a single relative measurement are explored. Recognition experiments were conducted to assess the discriminative capabilities of relative measurements as a biometric. Relative measurements can also be obtained from other forms of human representation. This is demonstrated using several machine learning techniques to determine relative measurements from gait biometric signatures. Retrieval results are presented showing the ability to automatically search video footage using comparative descriptions.

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Ariyanto, Gunawan. "Model-based 3D gait biometrics". Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/352080/.

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Gait biometrics has attracted increasing interest in the computer vision and machine learning communities because of its unique advantages for recognition at distance. However, there have as yet been few gait biometric approaches which use temporal three-dimensional(3D) data. Clearly, 3D gait data conveys more information than 2D gait data and it is also the natural representation of human gait as perceived by humans.The University of Southampton has created a multi-biometric tunnel using twelve cameras to capture multiple gait images and reconstruct them into 3D volumetric gait data. Some analyses have been done using this 3D dataset mainly to solve the view dependent problem using model-free silhouette-based approaches. This thesis explores the potential of model-based methods in an indoor 3D volumetric gait dataset and presents a novel human gait features extraction algorithm based on marionette and mass-spring principles. We have developed two different model-based approaches to extract human gait kinematics from 3D volumetric gait data. The first approach used a structural model of a human. This model contained four articulated cylinders and four joints with two degrees of rotational freedom at each joint to model the human lower legs. Human gait kinematic trajectories were extracted by fitting the gait model to the gait data. We proposed a simple yet effective model-fitting algorithm using a correlation filter and dynamic programming. To increase the fitting performance, we utilized a genetic algorithm on top of this structural model. The second approach was a novel 3D model-based approach using a marionette-based mass-spring model. To model the articulated human body, we used a stick-figure model which emulates marionette's motion and joint structure. The stick-figure model had eleven nodes representing the human joints of head, torso and lower legs. Each node was linked with at least one other node by spring. The voxel data in the next frame had a role as an attractor which able to generate forces for each node and then iteratively warp the model into the data. This process was repeated for successive frames. Our methods can extract both structural and dynamic gait features. Some of the extracted features were inherently unique to 3D gait data such as footprint angle and pelvis rotation. Analysis on a database of 46 subjects shows an encouraging correct classification rate up to 95.1% and suggests that model-based 3D gait analysis can contribute even more in gait biometrics.

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Syed, Idrus Syed Zulkarnain. "Soft biometrics for keystroke dynamics". Caen, 2014. http://www.theses.fr/2014CAEN2024.

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Aujourd'hui, il existe de multiples usages des systèmes biométriques à de nombreuses fins telles que le contrôle d'accès physique, le contrôle de présence, le paiement électronique et autres. Cette thèse de doctorat porte sur l'authentification biométrique et nous proposons d'utiliser la dynamique de frappe au clavier afin d'éviter les problèmes d'authentification par mot de passe. La dynamique de frappe au clavier mesure les rythmes qui se dégagent lorsqu'on tape sur un clavier d'ordinateur. En ce sens, c'est une modalité biométrique comportementale, de même que la dynamique de signature, la démarche ou la voix. Parmi les avantages de la dynamique de frappe au clavier par rapport à d'autres modalités, nous pouvons mentionner son faible coût et sa facilité d'usage : en effet, aucun capteur ni dispositif supplémentaire n'est nécessaire et les utilisateurs sont habitués à taper un mot de passe. En contrepartie, la dynamique de frappe présente de plus faibles performances que les autres modalités biométriques comme les empreintes digitales, le visage, l'iris. Cela peut s'expliquer par une variabilité intra-classe élevée. Une façon de gérer cette variabilité est de prendre en compte des informations supplémentaires dans le processus de décision. Cela peut être fait de différentes manières : (i) en combinant la dynamique de frappe au clavier avec une autre modalité biométrique (multibiométrie); (ii) en optimisant l'étape d'enrôlement (une donnée biométrique est exploitée pour la génération de la référence seulement si le niveau de qualité est suffisant); ou (iii) avec une solution nouvelle et prometteuse: la biométrie douce (profilage de l'utilisateur). Nous abordons dans cette thèse ces deux derniers aspects. Nous proposons plusieurs contributions afin d'améliorer les performances des systèmes de dynamique de frappe au clavier. Tout d'abord, nous avons créé notre propre jeu de données, qui est une nouvelle base de données biométrique appelée 'GREYC-NISLAB Keystroke'. Nous avons collecté les données de 110 utilisateurs en France et en Norvège. Cette nouvelle base est publique et contient des informations de profilage des utilisateurs: la façon de taper (une main ou deux mains), le genre, l'âge et la latéralité manuelle (droiter ou gaucher). Nous avons effectué diverses études afin de déterminer le taux de reconnaissance des critères de biométrie douce : (i) la façon de taper (une main ou deux mains); (ii) le genre (masculin ou féminin); (iii) la classe d'âge (moins de 30 ans ou plus de 30 ans); et (iv) la latéralité manuelle (droitier ou gaucher) des utilisateurs en fonction de leur façon de taper au clavier. Nous montrons qu'il est possible de reconnaître le profil de l'utilisateur en fonction de ces critères. Par la suite, nous proposons une fusion de différentes acquisitions de la dynamique de frappe afin d'accroître les performances du système. Enfin, en combinant les processus d'authentification avec les profils de biométrie douce, nous présentons une amélioration de l'authentification. Les résultats de nos expériences montrent les avantages des méthodes proposées
At present, there are a number of usages of biometric systems for many specific purposes such as physical access control, attendance monitoring, electronic payment (e-payment) and others. This PhD thesis focuses on biometric authentication and we propose to use keystroke dynamics in order to avoid password-based authentication problems. Keystroke dynamics measures the rhythm a person exhibits while typing on a keyboard. In this sense, keystroke dynamics is a behavioral biometric modality, as well as signature dynamics, gait and voice. Among the advantages of keystroke dynamics in comparison to other modalities, we can mention that it is a low cost and usable modality: indeed, no extra sensor or device is required and users often type a password. The counterpart to these advantages is the worse performance compared to morphological biometric modalities such as fingerprint, face or iris. The rather worse performances of keystroke dynamics can be explained by the high intra-class variability of the users' behaviour. One way to handle this variability is to take into account additional information in the decision process. This can be done with: (i) multibiometrics (by combining keystroke and another modality); (ii) optimising the enrolment step (a template is stored as reference only if its quality level is sufficient); or (iii) with a new and promising solution: soft biometrics (profiling the user). We address in this PhD thesis these two last aspects. We propose several contributions in order to enhance the performance of keystroke dynamics systems. First, we created a benchmark dataset called 'GREYC-NISLAB Keystroke' with biometric data collection from 110 users in France and Norway. This new benchmark database is available to the international scientific community and contains some profiling information on users: the way of typing (one hand or two hands), gender, age and handedness. We then perform various studies in order to determine the recognition accuracy of soft biometric traits given keystroke dynamics features: (i) the way of typing (one hand or two hands); (ii) gender (male or female); (iii) age class (below 30 or 30 and above); and (iv) handedness (right-handed or left-handed). Subsequently, we study the biometric fusion with keystroke dynamics in order to increase the soft biometrics recognition performance. Finally, by combining the authentication process with soft criteria, we present an improvement of user verification. The results of our experiments show the benefits of the proposed methods

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Svoboda, Jan. "System for Recognition of 3D Hand Geometry". Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2014. http://www.nusl.cz/ntk/nusl-412913.

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V posledním desetiletí došlo ke zvýšení zájmu o užití 3D dat k biometrické identifikaci osob. Možná vůbec největší výzkum proběhl v oblasti 3D rozpoznávání podle obličeje, přičemž je v současné době dostupných vícero komerčních zařízení. V oblastni rozpoznávání podle 3D geometrie ruky byl v minulých letech proveden určitý výzkum jehož výsledkem však nebylo žádné komerční zařízení. Nezávisle na tomto výzkumu se v posledních letech velmi rozšířil trh s cenově dostupnými 3D sensory, což potenciálně umožňuje jejich nasazení v mnoha typech biometrických systémů. Hlavním cílem této práce je vytvořit funkční vzorek bezdotykového systému pro rozpoznávání osob podle 3D geometrie ruky, který bude používat novou levnou kameru RealSense 3D vyvíjenou v současné době firmou Intel. Jedním z problémů při použití RealSense kamery je její velmi malý form factor, který je příčinou nižší kvality výsledných snímků v porovnání s velmi drahými alternativami, které byly použity v již dříve zmíněném výzkumu 3D biometrických systémů. Práce se snaží analyzovat robustnost různých 2D a 3D příznaků a vyzkoušet několik různých přístupů k jejich fúzi. Rovněž je vyhodnocena výkonnost výsledného systému, kde je ukázáno, že navržené řešení dosahuje výsledků porovnatelných se state-of-the-art.

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Viana, Rodrigo Sartorelo Salemi [UNESP]. "Programação linear à criação de planejamentos otimizados em radioterapia". Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/87916.

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Made available in DSpace on 2014-06-11T19:23:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-22Bitstream added on 2014-06-13T19:28:51Z : No. of bitstreams: 1 viana_rss_me_botib.pdf: 778475 bytes, checksum: 024e8c40dfa8c250c876d1b70410fee5 (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Um planejamento para radioterapia é considerado ótimo quando todos os parâmetros envolvidos sejam eles físicos ou biológicos, foram investigados e adequados individualmente para cada paciente. Neste tipo de planejamento, a grande preocupação é com a irradiação do tumor com o mínimo dano possível aos tecidos saudáveis da região irradiada, principalmente aos órgãos de riscos. O planejamento ótimo para radioterapia pode ser auxiliado pela Programação Linear e existe uma ampla literatura abordando este assunto, mas, a maioria das formulações matemáticas publicadas não contemplam um cenário do ponto de vista de aplicações práticas, pois não incorporam determinados fatores que são de extrema importância para a construção de um planejamento real, como exemplos a atenuação do feixe de radiação e a beterogeneidade na composição dos tecidos irradiados. Assim, este trabalho apresenta uma metodologia para correção de heterogeneidade na composição dos diferentes tipos de tecidos irradiados baseado nas proporções entre seus diferentes coeficientes de atenuação linear. Esta metodologia tem como objetivo tornar as simulações de planejamentos otimizados mais próximos dos planejamentos reais e desta forma, possibilitar um estudo mais amplo e confiável, faznedo com que modelos de programação linear possam ser utilizados como ferramentas auxiliares na criação de planejamentos reais para radioterapia
Planning for radiotherapy is considered optimal when all the parameters involved, physical or biological, have been investigated and are appropriate for each patient. In this type of planning, the major concern is with the irradiation of the tumor with the minimum possible damage to healthly tissues of the irradiated region, especially the organs at risk. The optimal planning for radiation therapy can be aided by Linear Programming and there is a wide literature addressing this subject. However, most published mathematical formulations do not contemplate a scenario in terms of practical applications. They do not incorporate certain factors that are extremely important for building a real planning, as examples there are attenuation of the radiation beam and the heterogeneous composition of the irradiated tissue. This work presents a methodology for correction of heterogeneity in the composition of different types of tissuers irradiated based on the proportions among their different linear attenuation coefficient. This methodology aims to make the simulations of optimized planning closer to the real planning and thus enable a more comprehensive and reliable, allowing the use of linear programming models as aids in the creation of real planning for radiotherapy

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Larco, Bravo Julio Cesar. "Autenticação pessoal baseada no som da assinatura". [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260146.

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Orientador: João Baptista Tadanobu Yabu-uti
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: Uma assinatura manuscrita, é a forma mais utilizada para con?rmar a dentidade de uma pessoa, já a que o estilo de assinar de um indivíduo é uma entidade biométrica que pode ser usada para diferenciar uma pessoa de outra. Neste trabalho, apresenta-se uma metodologia para realizar a autentica¸ao pessoal utilizando o som que se produz no momento de assinar.Quando uma pessoa assina, a fricção entre a ponta rígida de uma caneta e o papel produz um som que pode ser usado para veri?car a identidade de uma pessoa. Esta metodologia, está a baseada no fato de que o som produzido ao a correlacionado com a dinâmica e a postura do assinante. Cada um dos traços que compõe a assinatura corresponde a uma parte do sinal de som. Diferentes indivíduos produzem diferentes traços ou garranchos os quais resultam em diferentes sinais de som. Do sinal de som capturado são correspondem ao som da assinatura e calcula-se a envoltória deste sinal. Cada um dos traços que formam parte da assinatura são caracterizados como variações agudas nos valores da envoltória (picos), as quais ao representadas como vetores binários de características que são enviados para uma etapa de reconhecimento de padrões, a qual decidirá se o som capturado provém de uma assinatura que foi realizada por um usuúario legítimo ou por um impostor. A metodologia apresentada é avaliada utilizando um conjunto de amostras de teste e treinamento pertencentes a dois tipos de usuários: legítimo e impostor habilidoso. O usuário legítimo é o proprietário da assinatura e o impostor habilidoso comhece a forma como o usuário legítimo assina. Como parâmetros de avaliação do desempenho desta metodologia, foram obtidas as taxas de erro FAR (falsa aceitação) e FRR (falsa rejeição) de 8,55% e 8,73%, respectivamente
Abstract: A signature is the most used way to validate a person¿s identity, since the style of every individual signature constitutes a biometric entity, whichcan be used to differentiate one person from another. This research work presents a method to accomplish the personal authentication using the sound produced when a person is signing. During this event, the friction produced by the rigid tip of a pen rubbing the paper, generates a sound that can be used to verify the identity of a person. The reliability of this methodology is based on the fact that the sound emitted during the signature action is closely correlated with the dynamics and posture of the person who signs.Moreover, every line ofthe signature corresponds directlyto one partofthe audio signal generated. Therefore, diferent individuals are able to produce completely different traces or scrawls, which will generate different audio signals. Once the audio signal is digitally captured, the samples that do not belong to the signature are discardedandthe envelope ofthis signal is computed. Everyconstituent trace of the signature are characterizedas sharpvariations of the envelope values (peaks), whichare represented as binary vectors of features. This information, is sent to a pattern recognizing stage which has the responsibility to decide whether the captured sound corresponds to an authentic user or an impostor. The presented methodology is evaluated using a group of test and training samples belongingto two types ofusers: legitimate and skilled impostor.The legitimate user is the proprietor of the signature and the skilled impostor knows the form as the legitimate user signs. As parameters of evaluation of this methodology, were obtained the error rate FAR (false acceptance) and FRR (false rejection) of 8,55% and 8,73%, respectively
Mestrado
Mestre em Engenharia Elétrica

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Kodaira, Juliana Yukari. "Uma abordagem probabilística do número de reprodução básica em modelos epidemiológicos com aplicação na ferrugem do eucalipto /". Botucatu, 2011. http://hdl.handle.net/11449/87914.

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Orientador: José Raimundo de Souza Passos
Banca: Edson Luiz Furtado
Banca: Laécio Carvalho de Barros
Resumo: Na epidemiologia matemática, uma importante medida derivada do modelo determinístico associado à dinâmica de transmissão de uma doença infecciosa é o número esperado de infecções secundárias produzidas por um caso indexado em uma população completamente suscetível, conhecido como número de reprodução básica R0. Utilizando simulações de Monte Carlo, estudamos o efeito da incerteza sobre R0 em modelos compartimentos de transmissão de doenças, associando variáveis aleatórias uniformemente distribuídas a cada parâmetro constituinte de R0. Esta pertubação sobre os parâmetros corresponde à imprecisão intrínseca de seus valores na natureza. Neste trabalho também consideramos diferentes intervalos para as taxas de transmissão de doença com o intuito de avaliar seus efeitos dinâmicos. Aplicamos este método à modelagem da ferrugem do eucalipto, que é uma doença muito comum e severa em plantações de Eucalyptus spp. e outras mirtáceas, transmitida pelo fungo Puccinia psidii Winter. Hoje o eucalipto possui importância significativa tanto no mercado nacional quanto internacional e, portanto, iniciativas que auxiliem seu manejo integrado de doenças são imprescindíveis. Nossos resultados mostram que o método utilizado é eficiente, pois representa a influência das taxas de transmissão de doença no padrão da distribuição de probabilidade aproximada de R0, permitindo a obtenção das funções empíricas percentílicas complementares para os modelos considerados
Abstract: In mathematical epidemiology, an important measure derived from the deterministic model associated with the transmission dynamics of an infectious disease is the expected number of secondary infections produced by an indexed case in a completely susceptible population, known as the basic reproduction number R0. Using Monte Carlo simulations, we studied the effect of the uncertainty on R0 in compartmental disease transmission models, associating random variables uniformly distributed to each constituent parameter of R0. This perturbation on the parameters correspond to the intrinsic imprecision of their values in nature. In this work we also consider different ranges for the disease transmission rates in order to evaluate their dynamical effects. We apply this method to the eucalyptus rust, which is a very common and severe disease in plantations of Eucalyptus spp. and others Myrtaceae, transmitted by the fungus Puccinia psidii Winter. Today, eucalyptus has significant importance in both national and international market. Therefore, initiatives to help its integrated disease management are essential. Our results show that the method is efficient, since it represents the influence of the disease transmission rates in the approximated probability distribution pattern of R0, allowing us to obtain the empirical percentile complementary functions for the considered models
Mestre

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31

Alsaade, Fawaz. "Score-level fusion for multimodal biometrics". Thesis, University of Hertfordshire, 2008. http://hdl.handle.net/2299/1364.

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This thesis describes research into the score-level fusion process in multimodal biometrics. The emphasis of the research is on the fusion of face and voice biometrics in the two recognition modes of verification and open-set identification. The growing interest in the use of multiple modalities in biometrics is due to its potential capabilities for eradicating certain important limitations of unimodal biometrics. One of the factors important to the accuracy of a multimodal biometric system is the choice of the technique deployed for data fusion. To address this issue, investigations are carried out into the relative performance of several statistical data fusion techniques for combining the score information in both unimodal and multimodal biometrics (i.e. speaker and/ or face verification). Another important issue associated with any multimodal technique is that of variations in the biometric data. Such variations are reflected in the corresponding biometric scores, and can thereby adversely influence the overall effectiveness of multimodal biometric recognition. To address this problem, different methods are proposed and investigated. The first approach is based on estimating the relative quality aspects of the test scores and then passing them on into the fusion process either as features or weights. The approach provides the possibility of tackling the data variations based on adjusting the weights for each of the modalities involved according to its relative quality. Another approach considered for tackling the effects of data variations is based on the use of score normalisation mechanisms. Whilst score normalisation has been widely used in voice biometrics, its effectiveness in other biometrics has not been previously investigated. This method is shown to considerably improve the accuracy of multimodal biometrics by appropriately correcting the scores from degraded modalities prior to the fusion process. The investigations in this work are also extended to the combination of score normalisation with relative quality estimation. The experimental results show that, such a combination is more effective than the use of only one of these techniques with the fusion process. The thesis presents a thorough description of the research undertaken, details the experimental results and provides a comprehensive analysis of them.

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Pillay, Surosh Govindasamy. "Voice biometrics under mismatched noise conditions". Thesis, University of Hertfordshire, 2011. http://hdl.handle.net/2299/5531.

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This thesis describes research into effective voice biometrics (speaker recognition) under mismatched noise conditions. Over the last two decades, this class of biometrics has been the subject of considerable research due to its various applications in such areas as telephone banking, remote access control and surveillance. One of the main challenges associated with the deployment of voice biometrics in practice is that of undesired variations in speech characteristics caused by environmental noise. Such variations can in turn lead to a mismatch between the corresponding test and reference material from the same speaker. This is found to adversely affect the performance of speaker recognition in terms of accuracy. To address the above problem, a novel approach is introduced and investigated. The proposed method is based on minimising the noise mismatch between reference speaker models and the given test utterance, and involves a new form of Test-Normalisation (T-Norm) for further enhancing matching scores under the aforementioned adverse operating conditions. Through experimental investigations, based on the two main classes of speaker recognition (i.e. verification/ open-set identification), it is shown that the proposed approach can significantly improve the performance accuracy under mismatched noise conditions. In order to further improve the recognition accuracy in severe mismatch conditions, an approach to enhancing the above stated method is proposed. This, which involves providing a closer adjustment of the reference speaker models to the noise condition in the test utterance, is shown to considerably increase the accuracy in extreme cases of noisy test data. Moreover, to tackle the computational burden associated with the use of the enhanced approach with open-set identification, an efficient algorithm for its realisation in this context is introduced and evaluated. The thesis presents a detailed description of the research undertaken, describes the experimental investigations and provides a thorough analysis of the outcomes.

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Rankin, Deborah M. "Automated image analysis of Iris biometrics". Thesis, University of Ulster, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.587480.

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The iris of the eye is considered to be the most discriminatory of facial features. It is often assumed that an individual's iris pattem remains unchanged throughout their lifetime. However, clinical findings suggest that changes in the iris can occur due to ageing and in response to external factors such as medications, disease and surgery. Such changes in the appearance of the iris need to be addressed when considering the iris as a biometric. The extent of change over time and whether this affects the appearance of the iris sufficiently to impact on its value as a biometric measure requires investigation. To enable a detailed study of iris stability, a novel database of high resolution iris images is presented comprising 364 irides with images captured at regular time intervals. To facilitate iris analysis, an enhanced localisation method is proposed for iris segmentation. An extensive evaluation of a number of feature extraction algorithms is described and applied to a database of iris images captured over increasing time intervals of three, six, nine and twelve months. Irides are analysed in order to determine whether significant variation exists between images captured at increasing time lapses and to assess the impact of such variations on recognition performance. Iris matching schemes are also evaluated and compared. Results are presented in which increased dissimilarity is observed in iris comparisons as the time interval between comparisons increases. These differences increase the probability of recognition failure in iris recognition. A greater number of recognition failures are observed as the time lapse between images increases. Such failures are also found to differ depending on iris texture pattern. It is concluded that whilst the iris remains an appropriate biometric identifier, it may not be as stable as originally proposed. Further research is required to determine the causes of the observed longitudinal variation in iris pattem and the possible impact on iris recognition systems.

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Fortuna, JoseÌ. "Speaker indexing based on voice biometrics". Thesis, University of Hertfordshire, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427534.

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Drosou, Anastasios. "Activity related biometrics for person authentication". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/23659.

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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.

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Kruszynski, Joshua A. "Biometrics in Interaction and Interface Design". Kent State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=kent1468694579.

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WANG, HAOCHEN. ""Gaze-Based Biometrics: some Case Studies"". Doctoral thesis, Università degli studi di Pavia, 2018. http://hdl.handle.net/11571/1280026.

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WANG, HAOCHEN. ""Gaze-Based Biometrics: some Case Studies"". Doctoral thesis, Università degli studi di Pavia, 2018. http://hdl.handle.net/11571/1280066.

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WANG, HAOCHEN. ""Gaze-Based Biometrics: some Case Studies"". Doctoral thesis, Università degli studi di Pavia, 2018. http://hdl.handle.net/11571/1280086.

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Buriro, Attaullah. "Behavioral Biometrics for Smartphone User Authentication". Doctoral thesis, Università degli studi di Trento, 2017. https://hdl.handle.net/11572/368167.

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Pervasive in nature and extensively used for a wide range of features, smartphone provides functionality such as social networking, online shopping, mobile gaming, private/group communication, etc. While using these services, a user has to provide private information such as account credentials, credit card details, etc., which are then stored on the device. This information, if lost, can result in a user's privacy leakage and monetary loss. Therefore, significance of securing a smartphone from adversarial access becomes paramount. Despite being security and privacy critical, smartphones are still protected by traditional authentication mechanisms such as PINs and passwords, whose limitations and drawbacks are well known and well documented in the security community. The recent introduction of physical biometrics like facial, fingerprint and iris recognition, in smartphone authentication, has mitigated the problems with user input, however, they still suffer from other usability and security issues. Hence, new, accurate, and user-friendly authentication mechanisms are required. In this direction, behavior-based authentication solutions have recently attracted a significant amount of interest in both commercial and academic contexts. Most of the smartphone users prefer convenience over security and consider authentication mechanism more annoying as compared to other technological problems, such as lack of coverage, power consumption, etc. In this dissertation, we discuss limitations of existing authentication methods in terms of security and usability, and propose their replacements with behavioral biometric based authentication mechanisms. The underlying principle of our approach is to design solutions that authenticate users with either minimal or no cooperation from the users. We design, prototype and test the proposed authentication mechanisms based on our identified human behavior, such as how a person holds the phone, lifts the phone, types free-text PIN on the phone, signs her name on the touchscreen, etc. Moreover, we provide a comparative evaluation, based on accuracy, performance and usability, of our proposed mechanisms with the available state-of-the-art solutions. All of our solutions exploit the existing hardware (avoiding additional hardware requirement), and hence can be implemented on most of the smartphones available in the market today.

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Buriro, Attaullah. "Behavioral Biometrics for Smartphone User Authentication". Doctoral thesis, University of Trento, 2017. http://eprints-phd.biblio.unitn.it/1935/1/Final_Thesis_Attaullah.pdf.

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Pervasive in nature and extensively used for a wide range of features, smartphone provides functionality such as social networking, online shopping, mobile gaming, private/group communication, etc. While using these services, a user has to provide private information such as account credentials, credit card details, etc., which are then stored on the device. This information, if lost, can result in a user's privacy leakage and monetary loss. Therefore, significance of securing a smartphone from adversarial access becomes paramount. Despite being security and privacy critical, smartphones are still protected by traditional authentication mechanisms such as PINs and passwords, whose limitations and drawbacks are well known and well documented in the security community. The recent introduction of physical biometrics like facial, fingerprint and iris recognition, in smartphone authentication, has mitigated the problems with user input, however, they still suffer from other usability and security issues. Hence, new, accurate, and user-friendly authentication mechanisms are required. In this direction, behavior-based authentication solutions have recently attracted a significant amount of interest in both commercial and academic contexts. Most of the smartphone users prefer convenience over security and consider authentication mechanism more annoying as compared to other technological problems, such as lack of coverage, power consumption, etc. In this dissertation, we discuss limitations of existing authentication methods in terms of security and usability, and propose their replacements with behavioral biometric based authentication mechanisms. The underlying principle of our approach is to design solutions that authenticate users with either minimal or no cooperation from the users. We design, prototype and test the proposed authentication mechanisms based on our identified human behavior, such as how a person holds the phone, lifts the phone, types free-text PIN on the phone, signs her name on the touchscreen, etc. Moreover, we provide a comparative evaluation, based on accuracy, performance and usability, of our proposed mechanisms with the available state-of-the-art solutions. All of our solutions exploit the existing hardware (avoiding additional hardware requirement), and hence can be implemented on most of the smartphones available in the market today.

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Garcia, Iberê Anselmo. "A segurança na identificação: a biometria da íris e da retina". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/2/2136/tde-24062010-084048/.

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A presente dissertação aborda o processo de identificação por biometria das estruturas oculares, analisando suas bases biológicas e tecnológicas e sua aplicabilidade e confiabilidade para utilização jurídica. Está dividida em três partes. Na primeira, são analisados aspectos do conceito de identidade em suas diversas acepções e do processo de identificação médico legal por meio da utilização de diferentes métodos. Na segunda, passa-se a estudar a biometria da íris e da retina, abordando suas bases biológicas e tecnológicas. Na terceira e última parte, estuda-se a aplicabilidade e confiabilidade da biometria ocular para finalidades jurídicas, como método de perícia da identidade.
The purpose of this work is to study the identification process by ocular biometrics, from its biological and technological basis to its forensic and legal system applications. It is divided into three sections. The first section discusses the concept of identity and the identification methods used by forensic professionals. The second section discusses the ocular biometrics methods using iris and retinal traits, emphasizing their biological as well as their technological basis. The third and last section discusses the reliability and applicability of these biometrics modalities as identification methods in legal and forensic issues.

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Sanderson, Conrad, i conradsand@ieee org. "Automatic Person Verification Using Speech and Face Information". Griffith University. School of Microelectronic Engineering, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030422.105519.

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Identity verification systems are an important part of our every day life. A typical example is the Automatic Teller Machine (ATM) which employs a simple identity verification scheme: the user is asked to enter their secret password after inserting their ATM card; if the password matches the one prescribed to the card, the user is allowed access to their bank account. This scheme suffers from a major drawback: only the validity of the combination of a certain possession (the ATM card) and certain knowledge (the password) is verified. The ATM card can be lost or stolen, and the password can be compromised. Thus new verification methods have emerged, where the password has either been replaced by, or used in addition to, biometrics such as the persons speech, face image or fingerprints. Apart from the ATM example described above, biometrics can be applied to other areas, such as telephone & internet based banking, airline reservations & check-in, as well as forensic work and law enforcement applications. Biometric systems based on face images and/or speech signals have been shown to be quite effective. However, their performance easily degrades in the presence of a mismatch between training and testing conditions. For speech based systems this is usually in the form of channel distortion and/or ambient noise; for face based systems it can be in the form of a change in the illumination direction. A system which uses more than one biometric at the same time is known as a multi-modal verification system; it is often comprised of several modality experts and a decision stage. Since a multi-modal system uses complimentary discriminative information, lower error rates can be achieved; moreover, such a system can also be more robust, since the contribution of the modality affected by environmental conditions can be decreased. This thesis makes several contributions aimed at increasing the robustness of single- and multi-modal verification systems. Some of the major contributions are listed below. The robustness of a speech based system to ambient noise is increased by using Maximum Auto-Correlation Value (MACV) features, which utilize information from the source part of the speech signal. A new facial feature extraction technique is proposed (termed DCT-mod2), which utilizes polynomial coefficients derived from 2D Discrete Cosine Transform (DCT) coefficients of spatially neighbouring blocks. The DCT-mod2 features are shown to be robust to an illumination direction change as well as being over 80 times quicker to compute than 2D Gabor wavelet derived features. The fragility of Principal Component Analysis (PCA) derived features to an illumination direction change is solved by introducing a pre-processing step utilizing the DCT-mod2 feature extraction. We show that the enhanced PCA technique retains all the positive aspects of traditional PCA (that is, robustness to compression artefacts and white Gaussian noise) while also being robust to the illumination direction change. Several new methods, for use in fusion of speech and face information under noisy conditions, are proposed; these include a weight adjustment procedure, which explicitly measures the quality of the speech signal, and a decision stage comprised of a structurally noise resistant piece-wise linear classifier, which attempts to minimize the effects of noisy conditions via structural constraints on the decision boundary.

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Sumner, Kristine. "AIRPORT SECURITY: EXAMINING THE CURRENT STATE OF ACCEPTANCE OF BIOMETRICS AND THE PROPENSITY OF ADOPTING BIOMETRIC TECHNOLOGY FO". Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2475.

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The terrorist attacks of September 11, 2001 propelled the issue of aviation security to the forefront of the U.S. domestic agenda. Although hundreds of individual airports exist in the U.S., the travel activities at each of these airports combine to holistically comprise an aviation system that represents a significant portion of the U.S. social and economic infrastructure. Disruption at one airport resulting from a criminal act, such as terrorism, could exert detrimental effects upon the aviation system and U.S national security (9/11 Commission, 2004). Each U.S. airport is individually responsible for various aspects of security including the control of physical access to sensitive and secure areas and facilities (9/11 Commission, 2004). Biometric technology has been examined as one method of enhancing airport access control to mitigate the possibility of criminal acts against airports. However, successful implementation of biometric technology depends largely on how individual security directors at each airport perceive, understand, and accept that technology. Backgrounds, attitudes, and personal characteristics influence individual decisions about technology implementation (Rogers, 1995; Tornatzky and Fleischer, 1990). This study examines the problem of airport access control, as well as, the current trends in biometric technology. Utilizing a survey of airport security directors and security managers, this study draws upon innovation diffusion theory and organizational theories to determine what personal, organizational, and technical variables contribute to the propensity of airport security directors and managers to adopt biometric technology for airport access control.
Ph.D.
Department of Criminal Justice and Legal Studies
Health and Public Affairs
Public Affairs PhD

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Viana, Rodrigo Sartorelo Salemi. "Programação linear à criação de planejamentos otimizados em radioterapia /". Botucatu : [s.n.], 2010. http://hdl.handle.net/11449/87916.

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Orientador: Helenice de Oliveira Florentino Silva
Banca: Diana Rodrigues de Pina
Banca: Maria do Socorro Nogueira Rangel
Resumo: Um planejamento para radioterapia é considerado ótimo quando todos os parâmetros envolvidos sejam eles físicos ou biológicos, foram investigados e adequados individualmente para cada paciente. Neste tipo de planejamento, a grande preocupação é com a irradiação do tumor com o mínimo dano possível aos tecidos saudáveis da região irradiada, principalmente aos órgãos de riscos. O planejamento ótimo para radioterapia pode ser auxiliado pela Programação Linear e existe uma ampla literatura abordando este assunto, mas, a maioria das formulações matemáticas publicadas não contemplam um cenário do ponto de vista de aplicações práticas, pois não incorporam determinados fatores que são de extrema importância para a construção de um planejamento real, como exemplos a atenuação do feixe de radiação e a beterogeneidade na composição dos tecidos irradiados. Assim, este trabalho apresenta uma metodologia para correção de heterogeneidade na composição dos diferentes tipos de tecidos irradiados baseado nas proporções entre seus diferentes coeficientes de atenuação linear. Esta metodologia tem como objetivo tornar as simulações de planejamentos otimizados mais próximos dos planejamentos reais e desta forma, possibilitar um estudo mais amplo e confiável, faznedo com que modelos de programação linear possam ser utilizados como ferramentas auxiliares na criação de planejamentos reais para radioterapia
Abstract: Planning for radiotherapy is considered optimal when all the parameters involved, physical or biological, have been investigated and are appropriate for each patient. In this type of planning, the major concern is with the irradiation of the tumor with the minimum possible damage to healthly tissues of the irradiated region, especially the organs at risk. The optimal planning for radiation therapy can be aided by Linear Programming and there is a wide literature addressing this subject. However, most published mathematical formulations do not contemplate a scenario in terms of practical applications. They do not incorporate certain factors that are extremely important for building a real planning, as examples there are attenuation of the radiation beam and the heterogeneous composition of the irradiated tissue. This work presents a methodology for correction of heterogeneity in the composition of different types of tissuers irradiated based on the proportions among their different linear attenuation coefficient. This methodology aims to make the simulations of optimized planning closer to the real planning and thus enable a more comprehensive and reliable, allowing the use of linear programming models as aids in the creation of real planning for radiotherapy
Mestre

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46

Saevanee, Hataichanok. "Continuous user authentication using multi-modal biometrics". Thesis, University of Plymouth, 2014. http://hdl.handle.net/10026.1/3033.

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It is commonly acknowledged that mobile devices now form an integral part of an individual’s everyday life. The modern mobile handheld devices are capable to provide a wide range of services and applications over multiple networks. With the increasing capability and accessibility, they introduce additional demands in term of security. This thesis explores the need for authentication on mobile devices and proposes a novel mechanism to improve the current techniques. The research begins with an intensive review of mobile technologies and the current security challenges that mobile devices experience to illustrate the imperative of authentication on mobile devices. The research then highlights the existing authentication mechanism and a wide range of weakness. To this end, biometric approaches are identified as an appropriate solution an opportunity for security to be maintained beyond point-of-entry. Indeed, by utilising behaviour biometric techniques, the authentication mechanism can be performed in a continuous and transparent fashion. This research investigated three behavioural biometric techniques based on SMS texting activities and messages, looking to apply these techniques as a multi-modal biometric authentication method for mobile devices. The results showed that linguistic profiling; keystroke dynamics and behaviour profiling can be used to discriminate users with overall Equal Error Rates (EER) 12.8%, 20.8% and 9.2% respectively. By using a combination of biometrics, the results showed clearly that the classification performance is better than using single biometric technique achieving EER 3.3%. Based on these findings, a novel architecture of multi-modal biometric authentication on mobile devices is proposed. The framework is able to provide a robust, continuous and transparent authentication in standalone and server-client modes regardless of mobile hardware configuration. The framework is able to continuously maintain the security status of the devices. With a high level of security status, users are permitted to access sensitive services and data. On the other hand, with the low level of security, users are required to re-authenticate before accessing sensitive service or data.

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Hurley, David J. "Force field feature extraction for ear biometrics". Thesis, University of Southampton, 2001. https://eprints.soton.ac.uk/256792/.

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The overall objective in defining feature space is to reduce the dimensionality of the original pattern space, whilst maintaining discriminatory power for classification. To meet this objective in the context of ear biometrics a novel force field transformation is introduced in which the image is treated as an array of mutually attracting particles that act as the source of a Gaussian force field. In a similar way to Newton’s Law of Universal Gravitation pixels are imagined to attract each other according to the product of their intensities and inversely to the square of the distance between them. Underlying the force field there is a scalar potential energy field, which in the case of an ear takes the form of a smooth surface that resembles a small mountain with a number of peaks joined by ridges. The peaks correspond to potential energy wells and to extend the analogy the ridges correspond to potential energy channels. The directional properties of the force field are exploited to automatically locate these wells and channels, which then form the basis of a set of characteristic ear features. The new features are robust especially in the presence of noise, and have the advantage that the ear does not need to be explicitly extracted from its background. The directional properties of the ensuing force field lead to two equivalent extraction techniques; one is algorithmic and based on field lines, while the other is analytical and based on the divergence of force direction. The technique is validated by performing recognition on a database of ears selected from the XM2VTS face database. This confirms not only that ears do indeed appear to have potential as a biometric, but also that the new approach is well suited to their description.

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Allen, Anthony W. Jr. "Young Adult Perception and Acceptance of Biometrics". Youngstown State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1363891122.

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Zheng, Nan. "Exploiting behavioral biometrics for user security enhancements". W&M ScholarWorks, 2014. https://scholarworks.wm.edu/etd/1539623640.

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As online business has been very popular in the past decade, the tasks of providing user authentication and verification have become more important than before to protect user sensitive information from malicious hands. The most common approach to user authentication and verification is the use of password. However, the dilemma users facing in traditional passwords becomes more and more evident: users tend to choose easy-to-remember passwords, which are often weak passwords that are easy to crack. Meanwhile, behavioral biometrics have promising potentials in meeting both security and usability demands, since they authenticate users by "who you are", instead of "what you have". In this dissertation, we first develop two such user verification applications based on behavioral biometrics: the first one is via mouse movements, and the second via tapping behaviors on smartphones; then we focus on modeling user web browsing behaviors by Fitts' Law.;Specifically, we develop a user verification system by exploiting the uniqueness of people's mouse movements. The key feature of our system lies in using much more fine-grained (point-by-point) angle-based metrics of mouse movements for user verification. These new metrics are relatively unique from person to person and independent of the computing platform. We conduct a series of experiments to show that the proposed system can verify a user in an accurate and timely manner, and induced system overhead is minor. Similar to mouse movements, the tapping behaviors of smartphone users on touchscreen also vary from person to person. We propose a non-intrusive user verification mechanism to substantiate whether an authenticating user is the true owner of the smartphone or an impostor who happens to know the passcode. The effectiveness of the proposed approach is validated through real experiments. to further understand user pointing behaviors, we attempt to stress-test Fitts' law in the "wild", namely, under natural web browsing environments, instead of restricted laboratory settings in previous studies. Our analysis shows that, while the averaged pointing times follow Fitts' law very well, there is considerable deviations from Fitts' law. We observe that, in natural browsing, a fast movement has a different error model from the other two movements. Therefore, a complete profiling on user pointing performance should be done in more details, for example, constructing different error models for slow and fast movements. as future works, we plan to exploit multiple-finger tappings for smartphone user verification, and evaluate user privacy issues in Amazon wish list.

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Vogel, Robin. "Similarity ranking for biometrics : theory and practice". Electronic Thesis or Diss., Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAT031.

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L’augmentation rapide de la population combinée à la mobilité croissante des individus a engendré le besoin de systèmes de gestion d’identités sophistiqués. À cet effet, le terme biométrie se réfère généralement aux méthodes permettant d’identifier les individus en utilisant des caractéristiques biologiques ou comportementales. Les méthodes les plus populaires, c’est-à-dire la reconnaissance d’empreintes digitales, d’iris ou de visages, se basent toutes sur des méthodes de vision par ordinateur. L’adoption de réseaux convolutifs profonds, rendue possible par le calcul générique sur processeur graphique, ont porté les récentes avancées en vision par ordinateur. Ces avancées ont permis une amélioration drastique des performances des méthodes conventionnelles en biométrie, ce qui a accéléré leur adoption pour des usages concrets, et a provoqué un débat public sur l’utilisation de ces techniques. Dans ce contexte, les concepteurs de systèmes biométriques sont confrontés à un grand nombre de challenges dans l’apprentissage de ces réseaux. Dans cette thèse, nous considérons ces challenges du point de vue de l’apprentissage statistique théorique, ce qui nous amène à proposer ou esquisser des solutions concrètes. Premièrement, nous répondons à une prolifération de travaux sur l’apprentissage de similarité pour les réseaux profonds, qui optimisent des fonctions objectif détachées du but naturel d’ordonnancement recherché en biométrie. Précisément, nous introduisons la notion d’ordonnancement par similarité, en mettant en évidence la relation entre l’ordonnancement bipartite et la recherche d’une similarité adaptée à l’identification biométrique. Nous étendons ensuite la théorie sur l’ordonnancement bipartite à ce nouveau problème, tout en l’adaptant aux spécificités de l’apprentissage sur paires, notamment concernant son coût computationnel. Les fonctions objectif usuelles permettent d’optimiser la performance prédictive, mais de récents travaux ont mis en évidence la nécessité de prendre en compte d’autres facteurs lors de l’entraı̂nement d’un système biométrique, comme les biais présents dans les données, la robustesse des prédictions ou encore des questions d’équité. La thèse aborde ces trois exemples, en propose une étude statistique minutieuse, ainsi que des méthodes pratiques qui donnent les outils nécessaires aux concepteurs de systèmes biométriques pour adresser ces problématiques, sans compromettre la performance de leurs algorithmes
The rapid growth in population, combined with the increased mobility of people has created a need for sophisticated identity management systems.For this purpose, biometrics refers to the identification of individuals using behavioral or biological characteristics. The most popular approaches, i.e. fingerprint, iris or face recognition, are all based on computer vision methods. The adoption of deep convolutional networks, enabled by general purpose computing on graphics processing units, made the recent advances incomputer vision possible. These advances have led to drastic improvements for conventional biometric methods, which boosted their adoption in practical settings, and stirred up public debate about these technologies. In this respect, biometric systems providers face many challenges when learning those networks.In this thesis, we consider those challenges from the angle of statistical learning theory, which leads us to propose or sketch practical solutions. First, we answer to the proliferation of papers on similarity learningfor deep neural networks that optimize objective functions that are disconnected with the natural ranking aim sought out in biometrics. Precisely, we introduce the notion of similarity ranking, by highlighting the relationship between bipartite ranking and the requirements for similarities that are well suited to biometric identification. We then extend the theory of bipartite ranking to this new problem, by adapting it to the specificities of pairwise learning, particularly those regarding its computational cost. Usual objective functions optimize for predictive performance, but recentwork has underlined the necessity to consider other aspects when training a biometric system, such as dataset bias, prediction robustness or notions of fairness. The thesis tackles all of those three examplesby proposing their careful statistical analysis, as well as practical methods that provide the necessary tools to biometric systems manufacturers to address those issues, without jeopardizing the performance of their algorithms

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