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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

The Weakly Identifying System for Doorway Monitoring

Jenkins, Christopher James 10 May 2007 (has links)
The System Architecture for Tracking Individuals (SAFTI) is an indoor person location tracking system designed for use in the field of pervasive computing. SAFTI provides location tracking in environments where cameras are too privacy invasive, where tracking devices are too costly, insecure or inconvenient, and where usability is a high priority. While many location tracking systems satisfy each of these constraints individually, SAFTI satisfies all three constraints simultaneously. Upon entering and exiting SAFTI buildings, users submit identification credentials. Once inside the building, using SAFTI is effortless - simply passing through doorways is sufficient for supplying SAFTI with the information it needs to perform location tracking. An integral part of SAFTI is the Weakly Identifying System for Doorway Monitoring (WISDOM). These instrumented doorways contain a variety of infrared, ultrasonic and pressure sensors that detect the direction of passage and measure each user's body size and shape. We quantify the measurement and identification accuracy of WISDOM by analyzing data collected from a user study containing 530 passes through a WISDOM prototype from 10 different subjects. We combine the results from WISDOM with large publicly available anthropometric databases to evaluate how accurately SAFTI performs location tracking with respect to building size, density of occupants, and matching algorithm used. / Dissertation
52

Design and Implementation of User Authentication Based on Keystroke Dynamic

Hsin, Tsung-Chin 28 January 2008 (has links)
In the traditional login systems, we use the username and the password to identify the legalities of users. It is a simple and convenient way to identify, but passwords could be stolen or copied by someone who tries to invade the system illegally. Adding one protective mechanism to identify users, the way of biometrics are brought out, such as keystroke dynamics, fingerprints, DNA, retinas and so on that are unique characteristics of each individuals, it could be more effective in preventing trespassing. This thesis uses keystroke biometrics as research aspects of user authentication. The advantages of this system are low-cost and high security to identify users using keyboard to calculate the time of keystrokes. In this thesis, we use statistical way to examine the researches and experiments. Chosen length of the username and password are greater than or equal to 9 characters, and learning sample sizes are 20 and adapting the sample adaptation mechanism, the results show that we achieved by False Acceptance Rate of 0.85%, False Rejection Rate of 1.51% and Average False Rate of 1.18%; all reach the high levels of safeties.
53

A Comparison of Three Verification Methods for Keystroke Dynamic

Chen, Hsiao-ying 11 February 2009 (has links)
In login systems, a user is asked to enter his correct account and password in order to be allowed to enter to the system. The safety of systems is at the risk of leaking out the information, hence, the single mechanism of identity verification has not filled the bill at present. We study the personal typing behavior to get one¡¦s own specific features. In our thesis , we compare three methods and anlysis the advantages and shortcomings of those three. First one is to sort the twenty study data, and distribute the weights into the proper region. If the total weights is less than the threshold then this test data will be accepted, otherwise, it will be rejected. The second and third method are similar. Both of them are trying to rescale the data. The spirit of them is that the typing rate of a person will be faster when they type frequently and will be sloer when they are out of practice. However the relative positions of those keys, the lengths of ons¡¦s fingers, and the time that people making pauses in reading unpunctuated are unique. Those factors can be one¡¦s typing rhythm. There are twenty two individuals involved in this experiment. Each one choose his own proficient account and password to type and set up his typing model. The imposters are randomly choose legal user to imitate.
54

Biometrics in practice : The security technology of tomorrow's airports

Salavati, Sadaf January 2006 (has links)
<p>The biometric technology is a method for authentication which has been used since several centuries back. This is a technology which offers several different techniques where the human’s unique characteristics are used for identification and verification of the individual. Biometrics are today at a stage of development that is pointing upwards and many individuals that are well aware of the biometric world believes that this is the technology that will take over the security systems used today.</p><p>Ever since the terror attacks against USA at 2001, USA demanded that all 45 countries that today are not required to have visa when entering the United States must until the end of 2006 implement passports that contains biometrics information. The UN’s air traffic group on the other hand thinks that all counties in the world should use passports with biometric data. The biometric data in the passports are going to be stored in a chip and is in the first hand an image of the individuals face in a cryptic jpg format, but can also be complemented with fingerprints or even signature recognition. Sweden is currently using passports which contain biometric data but so far haven’t any machines that can read this passports been bought. Ulf Hägglund at Precise Biometrics AB believes that as soon as the real use of the biometric passports gets going the biometric technique will be used in a greater extension in the airports.</p><p>Even though several Swedish airports consider the security technique used in airports today being enough, biometrics can increase the security and at the same time simplify many security processes. Falsification can be reduced when at same time one can be sure that the same passenger who has checked-in is the passenger who boards the airplane and the employee security control can be totally automatized. Generally it can be said that “biometrics is a decent way to increase security in different areas”.</p> / <p>Den biometriska teknologin är en äkthetsbevisningsmetod som har används sedan flera århundraden tillbaka. Detta är en teknologi som erbjuder flera olika tekniker där människans unika karateristiska kännetecken används för identifiering och verifiering av individen. Biometrin befinner sig idag i ett utvecklingsstadie som pekar uppåt och flera personer som är insatta i biometrins värld anser att detta är den teknologi som kommer att ta över det nuvarande säkerhetssystemet.</p><p>Sedan terrorattentatet mot USA år 2001 har USA begärt att alla 45 länderna som idag inte behöver visum för att komma in till USA måste innan slutet av år 2006 införa pass som innehåller biometrisk information. FN; s luftfartsgrupp anser däremot att alla världens länder bör införa pass med biometrisk data. Den biometriska data som ska finnas i passen ska lagras i ett chip och är främst en avbildning av individens ansikte i krypterad jpg format men kan även tänkas bli kompletterat med fingeravtryck och eventuellt signatur igenkänning . I dagsläget använder sig Sverige av pass med biometrisk data, men än så länge har inte några maskiner som kan avläsa dessa pass köpts in. Ulf Hägglund på Precise Biometrics AB tror att så snart användandet av de biometriska passen kommer igång på riktigt kommer även den biometiska tekniken att användas i större utsträckning på flygplatser.</p><p>Trotts att flera svenska flygplatser idag anser att den säkerhetsteknik som används på flygplatserna idag räcker, kan man genom att använda sig av biometri öka säkerheten samtidigt som man förenklar många säkerhetsprocesser. Falsifieringen minskar samtidigt som man kan försäkra sig om att det alltid är samma passagerare som checkat- in som stiger på planet och säkerhetskontrollerna för de anställda kan bli total automatiserad. I stort kan man säga att ”biometrin är ett hyggligt steg mot att förbättra säkerheten inom olika områden”.</p>
55

Variability of Handwriting Biomechanics: A Focus on Grip Kinetics during Signature Writing

Ghali, Bassma 05 March 2014 (has links)
Grip kinetics are emerging as an important measure in clinical assessments of handwriting pathologies and fine motor rehabilitation as well as in biometric and forensic applications. The signature verification literature in particular has extensively examined the spatiotemporal, kinematic, and axial pressure characteristics of handwriting, but has minimally considered grip kinetics. Therefore, the focus of this thesis was to investigate the variability of grip kinetics in adults during signature writing. To address this goal, a database of authentic and well-practiced bogus signatures were collected with an instrumented pen that recorded the forces applied to its barrel. Four different analytical studies were conceived. The first study investigated the intra- and inter-participant variability of grip kinetic topography on the pen barrel based on authentic signatures written over 10 days. The main findings were that participants possessed unique grip force topographies even when the same grasp pattern was employed and that participants could be discriminated from each other with an average error rate of 1.2% on the basis of their grip force topographies. The second study examined the stability of different grip kinetic features over an extended period of a few months. The analyses revealed that intra-participant variation was generally much smaller than inter-participant variations even in the long term. In the third study, grip kinetics associated with authentic and well-practiced bogus signatures were compared. Differences in grip kinetic features between authentic and bogus signatures were only observed in a few participants. The kinetics of bogus signatures were not necessarily more variable. The variation of grip kinetic profiles between participants writing the same bogus signature was evaluated in the fourth study and an average error rate of 5.8% was achieved when verifying signatures with kinetic profile-based features. Collectively, the findings of this thesis serve to inform future applications of grip kinetic measures in biometric, clinical and industrial applications.
56

Variability of Handwriting Biomechanics: A Focus on Grip Kinetics during Signature Writing

Ghali, Bassma 05 March 2014 (has links)
Grip kinetics are emerging as an important measure in clinical assessments of handwriting pathologies and fine motor rehabilitation as well as in biometric and forensic applications. The signature verification literature in particular has extensively examined the spatiotemporal, kinematic, and axial pressure characteristics of handwriting, but has minimally considered grip kinetics. Therefore, the focus of this thesis was to investigate the variability of grip kinetics in adults during signature writing. To address this goal, a database of authentic and well-practiced bogus signatures were collected with an instrumented pen that recorded the forces applied to its barrel. Four different analytical studies were conceived. The first study investigated the intra- and inter-participant variability of grip kinetic topography on the pen barrel based on authentic signatures written over 10 days. The main findings were that participants possessed unique grip force topographies even when the same grasp pattern was employed and that participants could be discriminated from each other with an average error rate of 1.2% on the basis of their grip force topographies. The second study examined the stability of different grip kinetic features over an extended period of a few months. The analyses revealed that intra-participant variation was generally much smaller than inter-participant variations even in the long term. In the third study, grip kinetics associated with authentic and well-practiced bogus signatures were compared. Differences in grip kinetic features between authentic and bogus signatures were only observed in a few participants. The kinetics of bogus signatures were not necessarily more variable. The variation of grip kinetic profiles between participants writing the same bogus signature was evaluated in the fourth study and an average error rate of 5.8% was achieved when verifying signatures with kinetic profile-based features. Collectively, the findings of this thesis serve to inform future applications of grip kinetic measures in biometric, clinical and industrial applications.
57

Cryptographic Credentials with Privacy-preserving Biometric Bindings

Bissessar, David 22 January 2013 (has links)
Cryptographic credentials allow user authorizations to be granted and verified. and have such applications as e-Passports, e-Commerce, and electronic cash. This thesis proposes a privacy protecting approach of binding biometrically derived keys to cryptographic credentials to prevent unauthorized lending. Our approach builds on the 2011 work of Adams, offering additional benefits of privacy protection of biometric information, generality on biometric modalities, and performance. Our protocol integrates into Brands’ Digital Credential scheme, and the Anonymous Credentials scheme of Camenisch and Lysyanskaya. We describe a detailed integration with the Digital Credential Scheme and sketch the integration into the Anonymous Credentials scheme. Security proofs for non-transferability, correctness of ownership, and unlinkability are provided for the protocol’s instantiation into Digital Credentials. Our approach uses specialized biometric devices in both the issue and show protocols. These devices are configured with our proposed primitive, the fuzzy ex-tractor indistinguishability adaptor which uses a traditional fuzzy extractor to create and regenerate cryptographic keys from biometric data and IND-CCA2 secure en-cryption protect the generated public data against multiplicity attacks. Pedersen commitments are used to hold the key at issue and show time, and A zero-knowledge proof of knowledge is used to ensure correspondence of key created at issue-time and regenerated at show-time. The above is done in a manner which preserves biometric privacy, as and delivers non-transferability of digital credentials. The biometric itself is not stored or divulged to any of the parties involved in the protocol. Privacy protection in multiple enrollments scenarios is achieved by the fuzzy extractor indistinguishability adapter. The zero knowledge proof of knowledge is used in the showing protocol to prove knowledge of values without divulging them.
58

Uma abordagem probabilística do número de reprodução básica em modelos epidemiológicos com aplicação na ferrugem do eucalipto /

Kodaira, Juliana Yukari. January 2011 (has links)
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
59

Programação linear à criação de planejamentos otimizados em radioterapia

Viana, Rodrigo Sartorelo Salemi [UNESP] 22 February 2010 (has links) (PDF)
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
60

Eficiência da análise multifractal na verificação de assinaturas dinâmicas / Effectiveness of multifractal analysis for online signature verification

Canuto, Jânio Coutinho 08 December 2010 (has links)
Orientador: Lee Luan Ling / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-16T11:24:26Z (GMT). No. of bitstreams: 1 Canuto_JanioCoutinho_M.pdf: 5638185 bytes, checksum: a7de3e11ab9d81ea1011ac08ccef240a (MD5) Previous issue date: 2010 / 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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