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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.
111

The use of the Automated Fingerprint Identification System to improve the quality of service rendered by the South African Police Service on the East Rand

Matlala, Mpho Mark 2012 November 1900 (has links)
The globalisation process that drives the progression and trans-national nature of crime requires that the police should use sophisticated and/or state-of-the art technologies to help them to combat criminality. The use of technology by the police is thus viewed as one of the appropriate responses to deal with the threats posed by crime. In an attempt to ascertain the significance of technology in police work, this research examined the impact that the use of biometric technology such as the Automated Fingerprint Identification System, has had on the quality of seiVices rendered by the South African Police Service. Following the police's task of identifying criminal fingerprints, the problem encountered in this research was that, ever since the introduction of the Automated Fingerprint Identification System, no research had been conducted to assess the impact thereof on the level and quality of seiVices rendered by the South African Police SeiVice. This problem was further intensified by the fact that there was no framework to assess the impact that the utilisation of the Automated Fingerprint Identification System has had on police work in South Africa. Consequently, the problems that were identified in this research compromised not only the quality of seiVices rendered by the police, but also the safety and security within communities. The findings in this research showed that the utilisation of biometric technologies such as the Automated Fingerprint Identification System have helped the police to accurately identify and arrest criminal suspects. However, some of the conclusions reached suggested that the quantitative aspect of the utilisation of biometric systems and the elated portable apparatuses within the South African Police Service was emphasised more than the qualitative aspect thereof. The emphasis was evident in the statistics regarding the use of the Automated Fingerprint Identification System, which focused primarily on police productivity and to a lesser degree on accountability related issues. This study espoused a qualitative paradigm and the investigations in the research were focused on the East Rand policing precinct. The participants who informed this research were selected from the research population using random and purposive sampling techniques. In the same way, the data that informed this research was collected using semi-structured interviews and an in-depth review of the literature on policing and its utilisation of the different technologies. The research espoused social constructivism and phenomenology as the philosophical worldviews of choice to form constructivist phenomenology and to attain theoretical triangulation. Moreover, evaluation research and a case study were espoused as the research designs of choice, to attain methodological triangulation. The various triangulation techniques espoused in this research project were critical in attaining quality assurance in terms of the research methodology applied. In the same way, a myriad of qualitative techniques such as dependability, transferability, confimability and credibility were also employed in order to ensure that the integrity of the data that was collected in this study remained intact. Finally, the data that was collected to inform this research was analysed using the qualitative content analysis technique. Similarly, the measures taken to ensure that the safety of the research participants was delineated in this same research report. / Police Practice / M. Tech. (Police Science)
112

Fourier and Variational Based Approaches for Fingerprint Segmentation

Hoang Thai, Duy 28 January 2015 (has links)
No description available.
113

Diversidade taxonômica e potencial de biodegradação de bactérias isoladas de reservatórios de petróleo da Bacia de Campos (RJ). / Taxonomic diversity and biodegradation potential of bacteria isolated from oil reservoirs of the Campos Basin (RJ).

Lopes, Patrícia Ferreira 20 October 2010 (has links)
O presente trabalho teve como objetivos caracterizar uma coleção de 98 bactérias isoladas de amostras de petróleo e água de formação de reservatórios da Bacia de Campos (RJ) utilizando técnicas de taxonomia molecular e avaliar o potencial de degradação de biomarcadores do petróleo. O sequenciamento e análise filogenética do gene RNAr 16S revelaram Bacillus firmus, megaterium, pumilus, sphaericus, simplex, cereus/B. thuringiensis Marinobacter lutaoensis, Halomonas shengliensis/H. alimentaria/ H.campisalis, Citreicella thiooxidans, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, Micrococcus luteus, Kocuria rosea, Streptomyces alboniger/S. chartreusis /S. moderatus, Staphylococcus hominis e Staphylococcus pasteuri/S. warneri. Os resultados evidenciaram a preferência pela biotransformação do ácido nonadecanóico e esqualano. A caracterização da microbiota presente nos reservatórios e avaliação do potencial de biodegradação pode contribuir para fornecer subsídios para estudos futuros sobre os mecanismos biológicos responsáveis pela biodegradação do petróleo. / This study is aimed to characterize a collection of 98 bacteria isolated from oil and formation water samples derived from reservoirs of the Campos Basin (RJ) using molecular biology-based techniques and to evaluate the degradation potential of petroleum biomarkers. Further sequencing and phylogenetic analysis of 16S rRNA genes revealed species of Bacillus firmus, megaterium, pumilus, sphaericus, simplex, cereus/thuringiensis, Marinobacter lutaoensis, Halomonas shengliensis/H. alimentaria/H. campisalis, Citreicella thiooxidans, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, Micrococcus luteus, Kocuria rosea, Streptomyces alboniger/S. chartreusis/S. moderatus, Staphylococcus hominis and Staphylococcus pasteuri/S. warneri. The results showed the preference of bacteria for the biotransformation of nonadecanoic acid and squalane. The characterization of the microbiota associated to reservoirs and the evaluation of their biodegradation potential may provide subsidies for future studies about the biological mechanisms responsible for petroleum biodegradation.
114

Cromatografia líquida e análises quimiométricas na diferenciação química de acessos de Lippia alba (Mill) N. E. Brown e potenciais biológicos / Liquid Chromatography and chemometric analysis for the chemical differentiation of access of Lippia alba (Mill) N. E. Brown and biological potentials

Jesus, Raphael Amancio 20 February 2018 (has links)
Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The methodology developed in the present work, through chromatographic fingerprint by LC-DAD and Principal Component Analysis (PCA), was adequate for the chemical differentiation of Lippia alba (Mill) NE Brown accessions, considering the extraction method (infusion and maceration hydroalcoholic) and the collection season (summer and winter), allowing to evaluate the influence of these variables on the chemical composition of extracts obtained. In addition, all extracts were submitted to cytotoxic tests against two tumor cell lines, HL-60 (human leukemia) and HepG2 (human hepatocellular carcinoma), and to inhibition tests against the enzyme acetylcholinesterase (AChE) in order to evaluate the form of extraction and which access is the most promising from a pharmacological point of view. Among the extracts analyzed against tumor cells, eight of them, two from the infusion: 01IW and 02IW and six from the hydroalcoholic extraction: 02HW, 24HW, 39HW, 54HW, 01HS and 24HS, presented better cell inhibition performances against HL-60, with percentage of inhibition between 40.0 and 52.0%, suggesting that these extracts are potentially promising against this lineage. With respect to the anticholinesterase tests, all extracts studied had low AChE inhibitory effect when compared to galantamine (87.4%), highlighting only the samples 01HW (28.4%), 02HW (27.2%), 54HW (29.3%), 01HS (32.7%), 02HS (27.4%) and 24HS (30.3%). Through the analyzes performed by Nuclear Magnetic Resonance (NMR) it was possible to identify the structures of some compounds isolated from this species: flavone tricin and phenylpropanoid verbascoside/isoverbascoside. In addition, the classes of three other metabolites were proposed: two phenylpropanoid derivatives and one flavonoid diglucoside. / A metodologia desenvolvida no presente trabalho, utilizando fingerprint cromatográfico por CL-DAD e Análise de Componentes Principais (PCA), se mostrou adequado para a diferenciação química de acessos de Lippia alba (Mill) N. E. Brown, considerando o método de extração (infusão e maceração hidroalcoólica) e a época de coleta (verão e inverno), permitindo, ainda, avaliar a influência destas variáveis na composição química dos extratos obtidos. Adicionalmente, todos os extratos foram submetidos a testes citotóxicos frente a duas linhagens de células tumorais, HL-60 (leucemia humana) e HepG2 (carcinoma hepatocelular humano), e de inibição enzimática frente a acetilcolinesterase (AChE) com o intuito de avaliar qual a forma de extração e qual acesso é o mais promissor do ponto de vista farmacológico. Entre todos os extratos analisados frente as células tumorais, dois provenientes da infusão: 01II e 02II e seis da extração hidroalcoólica: 02HI, 24HI, 39HI, 54HI, 01HV e 24HV, apresentaram melhores desempenhos de inibição frente a HL-60, com percentual de inibição entre 40,0 e 52,0%, sugerindo que estes extratos são potencialmente promissores contra esta linhagem. Com relação aos testes anticolinesterásicos, todos os extratos estudados apresentaram baixo efeito inibidor da AChE quando comparados a galantamina (87,4%), com destaque para os extratos 01HI (28,4%), 02HI (27,2%), 54HI (29,3%), 01HV (32,7%), 02HV (27,4%) e 24HV (30,3%). Através das análises realizadas por Ressonância Magnética Nuclear (RMN) foi possível identificar as estruturas de alguns dos compostos isolados a partir desta espécie: a flavona tricina e o fenilpropanóide verbascosídeo/isoverbascosídeo. Além disso, foram propostas as classes de outros três metabólitos: dois derivados de fenilpropanóides e um flavonóide diglicosilado. / São Cristóvão, SE
115

Diversidade taxonômica e potencial de biodegradação de bactérias isoladas de reservatórios de petróleo da Bacia de Campos (RJ). / Taxonomic diversity and biodegradation potential of bacteria isolated from oil reservoirs of the Campos Basin (RJ).

Patrícia Ferreira Lopes 20 October 2010 (has links)
O presente trabalho teve como objetivos caracterizar uma coleção de 98 bactérias isoladas de amostras de petróleo e água de formação de reservatórios da Bacia de Campos (RJ) utilizando técnicas de taxonomia molecular e avaliar o potencial de degradação de biomarcadores do petróleo. O sequenciamento e análise filogenética do gene RNAr 16S revelaram Bacillus firmus, megaterium, pumilus, sphaericus, simplex, cereus/B. thuringiensis Marinobacter lutaoensis, Halomonas shengliensis/H. alimentaria/ H.campisalis, Citreicella thiooxidans, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, Micrococcus luteus, Kocuria rosea, Streptomyces alboniger/S. chartreusis /S. moderatus, Staphylococcus hominis e Staphylococcus pasteuri/S. warneri. Os resultados evidenciaram a preferência pela biotransformação do ácido nonadecanóico e esqualano. A caracterização da microbiota presente nos reservatórios e avaliação do potencial de biodegradação pode contribuir para fornecer subsídios para estudos futuros sobre os mecanismos biológicos responsáveis pela biodegradação do petróleo. / This study is aimed to characterize a collection of 98 bacteria isolated from oil and formation water samples derived from reservoirs of the Campos Basin (RJ) using molecular biology-based techniques and to evaluate the degradation potential of petroleum biomarkers. Further sequencing and phylogenetic analysis of 16S rRNA genes revealed species of Bacillus firmus, megaterium, pumilus, sphaericus, simplex, cereus/thuringiensis, Marinobacter lutaoensis, Halomonas shengliensis/H. alimentaria/H. campisalis, Citreicella thiooxidans, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, Micrococcus luteus, Kocuria rosea, Streptomyces alboniger/S. chartreusis/S. moderatus, Staphylococcus hominis and Staphylococcus pasteuri/S. warneri. The results showed the preference of bacteria for the biotransformation of nonadecanoic acid and squalane. The characterization of the microbiota associated to reservoirs and the evaluation of their biodegradation potential may provide subsidies for future studies about the biological mechanisms responsible for petroleum biodegradation.
116

The use of the Automated Fingerprint Identification System to improve the quality of service rendered by the South African Police Service on the East Rand

Matlala, Mpho Mark 11 1900 (has links)
The globalisation process that drives the progression and trans-national nature of crime requires that the police should use sophisticated and/or state-of-the art technologies to help them to combat criminality. The use of technology by the police is thus viewed as one of the appropriate responses to deal with the threats posed by crime. In an attempt to ascertain the significance of technology in police work, this research examined the impact that the use of biometric technology such as the Automated Fingerprint Identification System, has had on the quality of seiVices rendered by the South African Police Service. Following the police's task of identifying criminal fingerprints, the problem encountered in this research was that, ever since the introduction of the Automated Fingerprint Identification System, no research had been conducted to assess the impact thereof on the level and quality of seiVices rendered by the South African Police SeiVice. This problem was further intensified by the fact that there was no framework to assess the impact that the utilisation of the Automated Fingerprint Identification System has had on police work in South Africa. Consequently, the problems that were identified in this research compromised not only the quality of seiVices rendered by the police, but also the safety and security within communities. The findings in this research showed that the utilisation of biometric technologies such as the Automated Fingerprint Identification System have helped the police to accurately identify and arrest criminal suspects. However, some of the conclusions reached suggested that the quantitative aspect of the utilisation of biometric systems and the elated portable apparatuses within the South African Police Service was emphasised more than the qualitative aspect thereof. The emphasis was evident in the statistics regarding the use of the Automated Fingerprint Identification System, which focused primarily on police productivity and to a lesser degree on accountability related issues. This study espoused a qualitative paradigm and the investigations in the research were focused on the East Rand policing precinct. The participants who informed this research were selected from the research population using random and purposive sampling techniques. In the same way, the data that informed this research was collected using semi-structured interviews and an in-depth review of the literature on policing and its utilisation of the different technologies. The research espoused social constructivism and phenomenology as the philosophical worldviews of choice to form constructivist phenomenology and to attain theoretical triangulation. Moreover, evaluation research and a case study were espoused as the research designs of choice, to attain methodological triangulation. The various triangulation techniques espoused in this research project were critical in attaining quality assurance in terms of the research methodology applied. In the same way, a myriad of qualitative techniques such as dependability, transferability, confimability and credibility were also employed in order to ensure that the integrity of the data that was collected in this study remained intact. Finally, the data that was collected to inform this research was analysed using the qualitative content analysis technique. Similarly, the measures taken to ensure that the safety of the research participants was delineated in this same research report. / Police Practice / M. Tech. (Police Science)
117

Fehler von Fingerabdruckerkennungssystemen im Kontext / Begreifbare Vermittlung der Fehler einer biometrischen Kontrolltechnologie

Knaut, Andrea 12 September 2017 (has links)
In dieser Arbeit werden zwei Fragen im Zusammenhang mit Fehlern von Fingerabdruckerkennungssystemen untersucht. Erstens: Welche strukturellen Merkmale und begrifflichen Implikationen hat der spezifische Fehlerdiskurs in diesem Teilgebiet der Biometrie? Zur Beantwortung dieser Frage werden im Rahmen einer diskursanalytischen Betrachtung der Fachtexte des Forschungsfeldes die gängigen Fehlertypologien der Biometrie untersucht. Die Arbeitshypothese der Analyse ist, dass der massenhafte Einsatz von Fingerabdruckerkennungssystemen im Alltag trotz aller ihrer Fehler diskursiv durchsetzungsfähig ist. Undzwar nicht unbedingt, weil die Fehler zu vernachlässigen sind, sondern weil die Angst vor „Identitätsbetrug“, die Idee einer Messbarkeit von Identität und die wirtschaftliche und politische Bedeutung von Sicherheitstechniken in einer für unsicher gehaltenen Welt große Wirkmächtigkeit haben. Es wird diskutiert, inwiefern die Auseinandersetzung mit System- und Überwindungsfehlern in der Informatik zu kurz greift. Daher wird ein erweitertes Fehlermodell vorgeschlagen, das an jüngere transdisziplinäre Fehlerforschung anknüpft und als kritisches Analyseinstrument für die Beurteilung der Wechselwirkung zwischen Informatik(-system) und Gesellschaft genutzt werden kann. Zweitens: Wie lassen sich die diskursanalytische Methode und ein experimentelles Hands-On-Lernen zu einem Lern- und Lehrkonzept verbinden, dass eine kritische Vermittlung der Probleme von Fingerabdruckerkennungssystemen ermöglicht? Ausgehend von schulischen Unterrichtskonzepten einer an der Lebenswelt orientierten Informatiklehre sowie der Idee des „be-greifbaren Lernens“ an konkreten Gegenständen wurde ein Lern- und Lehrkonzept für Universität und Schule entwickelt und in drei verschiedenen Institutionen ausprobiert. / In this paper two questions will be addressed relating to deficits in fingerprint recognition systems. Firstly, what structural features and conceptual implications does the analysis of errors have in the field of biometrics? To answer this question, the common error types in biometrics will be examined, as part of an analytical discourse taking into consideration technical texts from the research field. The working hypothesis of this analysis is that the structure of the discourse surrounding fingerprint recognition systems would present no barriers to their widespread implementation in everyday life despite all their faults – not because their shortcomings are negligible but due to the great potency of the fear of “identity fraud”, the notion that identity can be measured, and the economic and political importance of security technologies in a world deemed unsafe. It will be discussed how the examination of system errors and spoofing attacks in computer science falls short in addressing the whole picture of failing fingerprint recognition systems. Therefore an extended error model will be proposed, one which builds on recent transdisciplinary error research and which can be used as a critical tool for analysing and assessing the interaction between computer systems and society. Secondly, how could the analytical discourse method and experimental hands-on learning be combined into a teaching concept that would enable critical teaching of the problems of fingerprint recognition systems? Starting from the school-based teaching concepts of a theory of computer science based on real life and the idea of “hands-on learning” using concrete objects, a teaching concept for universities and schools has been developed and tested in three different institutions.
118

Biometric authentication systems for secured e-transactions in Saudi Arabia : an empirical investigation of the factors affecting users' acceptance of fingerprint authentication systems to improve online security for e-commerce and e-government websites in Saudi Arabia

Al-Harby, Fahad Mohammed January 2010 (has links)
Security is becoming an increasingly important issue for business, and with it comes the need for appropriate authentication; consequently, it is becoming gradually more important to develop secure e-commerce systems. Fraud via the web, identity theft, and phishing are raising concerns for users and financial organisations. In addition, current authentication methods, like passwords, have many problems (e.g. some users write them down, they forget them, or they make them easy to hack). We can overcome these drawbacks by using biometric authentication systems. Biometric systems are being used for personal authentication in response to the rising issue of authentication and security. Biometrics provide much promise, in terms of preserving our identities without the inconvenience of carrying ID cards and/or remembering passwords. This research is important because the securing of e-commerce transactions is becoming increasingly important. Identity theft, hacking and viruses are growing threats to Internet users. As more people use the Internet, more identity theft cases are being reported. This could harm not only the users, but also the reputation of the organisations whose names are used in these illegal acts. For example, in the UK, online banking fraud doubled in 2008 compared to 2007. More users took to e-shopping and online banking, but failed to take necessary protection. For non-western cultures, the figures for web security, in 2008, illustrated that Saudi Arabia was ranked ninth worldwide for users who had been attacked over the web. The above statistics reflect the significance of information security with e-commerce systems. As with any new technology, user acceptance of the new technology is often hard to measure. In this thesis, a study of user acceptance of biometric authentication systems in e-transactions, such as online banking, within Saudi society was conducted. It examined whether Saudis are practically willing to accept this technology. This thesis focuses upon Saudi Arabia, which has developing economy. It has achieved a rapid rate of growth, and therefore makes an interesting and unique case study. From an economist's point of view, Saudi Arabia is the powerhouse of the Middle East. It has the leading regional economy, and, even though it is still relatively young. It has a young and rapid growing population; therefore, this makes Saudi Arabia an attractive potential market for all kinds of e-commerce applications. Having said that, with more than half of population under the age of 30 are more to be expected to take the risk of accepting new technology. For this work, 306 Saudi participants were involved in the experiments. A laboratory experiment was created that actively tested a biometric authentication system in combination with a survey. The Technology Acceptance Model (TAM) was adopted in the first experimental phase as the theoretical basis on which to develop the iv research framework, the model has proven its efficiency as a good predictor for the biometric authentication system. Furthermore, in a second experimental phase, the Unified Theory of Acceptance and Use of Technology (UTAUT) with moderating variables such as age, gender and education level was examined as a proposed conceptual framework to overcome the limitations of TAM. The aim of the study was to explore factors affecting users' acceptance of biometric authentication systems. The findings from Structural Equation Modelling (SEM) analysis indicate that education level is a significant moderating factor, while gender and age do not record as significant. This thesis added new knowledge to this field and highlighted the importance of the perceptions of users regarding biometric security technologies. It helps determine the factors affecting the acceptance of biometric technology. To our knowledge, this is the first systematic study of this issue carried out by academic and non-biased researchers in Saudi Arabia. Furthermore, the thesis presents security technology companies and developers of information security products with information to help in the determination of what is significant to their user base when taking into account the introduction of new secure systems and products.
119

Piršto atspaudo naudojimas šifravimo rakto generavimui / Encryption key generation from fingerprint

Burba, Donatas 13 August 2010 (has links)
Saugiais gali būti laikomi tik užšifruoti duomenys, o šifravimas neįmanomas be šifravimo rakto. Vienas iš geriausiai žinomų ir plačiausiai naudojamų šifravimo raktų yra slaptažodis, tačiau pagrindinis jo trūkumas tas, kad jį reikia atsiminti. Šioje situacijoje gali padėti biometrija, kadangi praktiškai kiekvienas žmogus turi unikalias charakteristikas. Tačiau pagrindinė problema yra - kaip iš biometrinių charakteristikų suformuoti šifravimo raktą. Pirštų atspaudai yra gerai žinoma biometrinė charakteristika, naudojama žmonių identifikavimui ir tapatybės patvirtinimui, o USB atmintinėse ar nešiojamuosiuose kompiuteriuose integruoti pirštų atspaudų skaitytuvai jau nieko nebestebina. Kiekvienas piršto atspaudas gali būti aprašytas minutiae taškų matrica iš kurios būtų galima generuoti šifravimo raktą. Tačiau netgi to paties piršto atspaudai nėra identiški ir į tai reikia atsižvelgti. Šiame darbe pateikiamas vienas tiesioginių šifravimo raktų generavimo iš pirštų atspaudų metodas. Iš atspaudo suformuojama minutiae taškų matrica, iš jos suformuojami parametrai ir perduodami raktų generatoriams. Matricų formavimui panaudoti du produktai, realizuoti 8 generatoriai, formuojantys 64 ir 128 bitų ilgio šifravimo raktus. Sistema ištestuota su pasiruošta pirštų atspaudų duomenų baze, pateikti gauti rezultatai. / Only encrypted data can be treated as secure data and encryption is impossible without encryption key. One of the best known and widely used encryption keys is password, but the main its drawback is necessity to remember it. Biometrics may help to avoid this situation, because everyone has unique characteristics. But the main question is how to extract encryption key from biometric data. Fingerprints are well known biometric characteristic, used for people identification or authentication and fingerprint readers integrated into USB flash drives or laptops don’t cause surprise any more. Every fingerprint can be described using minutiae points’ matrix and from this matrix encryption key can be generated. But fingerprints of the same finger aren’t identical, so this must be kept in mind as well. In this research one method of direct encryption key generation from fingerprint is introduced. Minutiae matrix is structured from fingerprint image; parameters are formed and passed to encryption key generators. Two products were used for making matrix and eight generators were produced, generating encryption keys length of 64 and 128 bits. This system was tested with prepared fingerprint set and all the results are given.
120

Triagem da composição química de amostras de cabelo humano antes e após modificação estética utilizando técnicas espectroanalíticas e quimiometria /

Santos, Mônica Cardoso. January 2019 (has links)
Orientadora: Fabíola Manhas Verbi Pereira / Banca: Hideko Yamanaka / Banca: Flavio Junior Caires / Banca: Luiz Alberto Colnago / Banca: Hudson Wallace Pereira de Carvalho / Resumo: O cabelo apresenta estabilidade elevada quanto à deterioração, que ocorre desde a coleta até a análise, o que pode permitir um amplo período de investigação entre alguns meses até anos. Nesse contexto, amostras de cabelo humano e sintético foram analisadas utilizando as técnicas de Fluorescência de raios X por dispersão de comprimento de onda (WDXRF) e Espectroscopia de emissão óptica com plasma induzido por laser (LIBS). A ideia dessa tese de doutorado foi identificar variações na composição química que pudessem diferenciar estas amostras. Além disso, foi efetuado nas amostras um procedimento de modificação estética comum como a descoloração dos cabelos. Assim, o objetivo foi avaliar o cabelo antes e após este procedimento para abranger uma ampla representatividade destas amostras. A partir das técnicas espectroanalíticas foi possível obter perfis espectrais e correlacioná-los com as amostras antes e após o procedimento de descoloração dos cabelos. Outro fato importante foi que os resultados mostraram a complementaridade entre as técnicas, permitindo estabelecer uma impressão digital para os diferentes tipos de cabelo. Com a utilização de técnicas quimiométricas foram desenvolvidos modelos de classificação, que apresentaram resultados promissores no que concerne as amostras antes e após o procedimento de descoloração do cabelo. / Abstract: Hair has a high stability against deterioration, from collection to analysis, which may allow a long period of investigation between a few months to years. In this context, human and synthetic hair samples were analyzed by using Wavelength Dispersive Xray Fluorescence (WDXRF) and Laser-Induced Breakdown Spectroscopy (LIBS) techniques. The idea of this PhD dissertation was to identify variations in the chemical composition that could differentiate these samples. In addition, a common aesthetic modification procedure, such as hair bleaching, was performed on the samples. Thus, the aim was to evaluate hair before and after this procedure to encompass a broad representation of these samples. From the spectroanalytical techniques it was possible to obtain spectral profiles and to correlate them with the samples before and after the hair discoloration procedure. Another important feature was that results showed the complementarity between both techniques, allowing to establish a fingerprint for the different types of hair. Using chemometric techniques, classification models were developed, which presented promising results regarding the samples before and after the hair bleaching procedure. / Doutor

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