582 research outputs found

    Multi-modal palm-print and hand-vein biometric recognition at sensor level fusion

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    When it is important to authenticate a person based on his or her biometric qualities, most systems use a single modality (e.g. fingerprint or palm print) for further analysis at higher levels. Rather than using higher levels, this research recommends using two biometric features at the sensor level. The Log-Gabor filter is used to extract features and, as a result, recognize the pattern, because the data acquired from images is sampled at various spacing. Using the two fused modalities, the suggested system attained greater accuracy. Principal component analysis (PCA) was performed to reduce the dimensionality of the data. To get the optimum performance between the two classifiers, fusion was performed at the sensor level utilizing different classifiers, including K-nearest neighbors (K-NN) and support vector machines (SVMs). The technology collects palm prints and veins from sensors and combines them into consolidated images that take up less disk space. The amount of memory needed to store such photos has been lowered. The amount of memory is determined by the number of modalities fused

    Securing Cloud Storage by Transparent Biometric Cryptography

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    With the capability of storing huge volumes of data over the Internet, cloud storage has become a popular and desirable service for individuals and enterprises. The security issues, nevertheless, have been the intense debate within the cloud community. Significant attacks can be taken place, the most common being guessing the (poor) passwords. Given weaknesses with verification credentials, malicious attacks have happened across a variety of well-known storage services (i.e. Dropbox and Google Drive) ā€“ resulting in loss the privacy and confidentiality of files. Whilst today's use of third-party cryptographic applications can independently encrypt data, it arguably places a significant burden upon the user in terms of manually ciphering/deciphering each file and administering numerous keys in addition to the login password. The field of biometric cryptography applies biometric modalities within cryptography to produce robust bio-crypto keys without having to remember them. There are, nonetheless, still specific flaws associated with the security of the established bio-crypto key and its usability. Users currently should present their biometric modalities intrusively each time a file needs to be encrypted/decrypted ā€“ thus leading to cumbersomeness and inconvenience while throughout usage. Transparent biometrics seeks to eliminate the explicit interaction for verification and thereby remove the user inconvenience. However, the application of transparent biometric within bio-cryptography can increase the variability of the biometric sample leading to further challenges on reproducing the bio-crypto key. An innovative bio-cryptographic approach is developed to non-intrusively encrypt/decrypt data by a bio-crypto key established from transparent biometrics on the fly without storing it somewhere using a backpropagation neural network. This approach seeks to handle the shortcomings of the password login, and concurrently removes the usability issues of the third-party cryptographic applications ā€“ thus enabling a more secure and usable user-oriented level of encryption to reinforce the security controls within cloud-based storage. The challenge represents the ability of the innovative bio-cryptographic approach to generate a reproducible bio-crypto key by selective transparent biometric modalities including fingerprint, face and keystrokes which are inherently noisier than their traditional counterparts. Accordingly, sets of experiments using functional and practical datasets reflecting a transparent and unconstrained sample collection are conducted to determine the reliability of creating a non-intrusive and repeatable bio-crypto key of a 256-bit length. With numerous samples being acquired in a non-intrusive fashion, the system would be spontaneously able to capture 6 samples within minute window of time. There is a possibility then to trade-off the false rejection against the false acceptance to tackle the high error, as long as the correct key can be generated via at least one successful sample. As such, the experiments demonstrate that a correct key can be generated to the genuine user once a minute and the average FAR was 0.9%, 0.06%, and 0.06% for fingerprint, face, and keystrokes respectively. For further reinforcing the effectiveness of the key generation approach, other sets of experiments are also implemented to determine what impact the multibiometric approach would have upon the performance at the feature phase versus the matching phase. Holistically, the multibiometric key generation approach demonstrates the superiority in generating the bio-crypto key of a 256-bit in comparison with the single biometric approach. In particular, the feature-level fusion outperforms the matching-level fusion at producing the valid correct key with limited illegitimacy attempts in compromising it ā€“ 0.02% FAR rate overall. Accordingly, the thesis proposes an innovative bio-cryptosystem architecture by which cloud-independent encryption is provided to protect the users' personal data in a more reliable and usable fashion using non-intrusive multimodal biometrics.Higher Committee of Education Development in Iraq (HCED

    Load Estimation, Structural Identification and Human Comfort Assessment of Flexible Structures

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    Stadiums, pedestrian bridges, dance floors, and concert halls are distinct from other civil engineering structures due to several challenges in their design and dynamic behavior. These challenges originate from the flexible inherent nature of these structures coupled with human interactions in the form of loading. The investigations in past literature on this topic clearly state that the design of flexible structures can be improved with better load modeling strategies acquired with reliable load quantification, a deeper understanding of structural response, generation of simple and efficient human-structure interaction models and new measurement and assessment criteria for acceptable vibration levels. In contribution to these possible improvements, this dissertation taps into three specific areas: the load quantification of lively individuals or crowds, the structural identification under non-stationary and narrowband disturbances and the measurement of excessive vibration levels for human comfort. For load quantification, a computer vision based approach capable of tracking both individual and crowd motion is used. For structural identification, a noise-assisted Multivariate Empirical Mode Decomposition (MEMD) algorithm is incorporated into the operational modal analysis. The measurement of excessive vibration levels and the assessment of human comfort are accomplished through computer vision based human and object tracking, which provides a more convenient means for measurement and computation. All the proposed methods are tested in the laboratory environment utilizing a grandstand simulator and in the field on a pedestrian bridge and on a football stadium. Findings and interpretations from the experimental results are presented. The dissertation is concluded by highlighting the critical findings and the possible future work that may be conducted

    Probabilistic prediction of Alzheimerā€™s disease from multimodal image data with Gaussian processes

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    Alzheimerā€™s disease, the most common form of dementia, is an extremely serious health problem, and one that will become even more so in the coming decades as the global population ages. This has led to a massive effort to develop both new treatments for the condition and new methods of diagnosis; in fact the two are intimately linked as future treatments will depend on earlier diagnosis, which in turn requires the development of biomarkers that can be used to identify and track the disease. This is made possible by studies such as the Alzheimerā€™s disease neuroimaging initiative which provides previously unimaginable quantities of imaging and other data freely to researchers. It is the task of early diagnosis that this thesis focuses on. We do so by borrowing modern machine learning techniques, and applying them to image data. In particular, we use Gaussian processes (GPs), a previously neglected tool, and show they can be used in place of the more widely used support vector machine (SVM). As combinations of complementary biomarkers have been shown to be more useful than the biomarkers are individually, we go on to show GPs can also be applied to integrate different types of image and non-image data, and thanks to their properties this improves results further than it does with SVMs. In the final two chapters, we also look at different ways to formulate both the prediction of conversion to Alzheimerā€™s disease as a machine learning problem and the way image data can be used to generate features for input as a machine learning algorithm. Both of these show how unconventional approaches may improve results. The result is an advance in the state-of-the-art for a very clinically important problem, which may prove useful in practice and show a direction of future research to further increase the usefulness of such method

    Interactions of fluorophores with complex surfaces and spectroscopic examinations of ancient manuscripts

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    In the first part of this thesis, it was found by fibre-optic fluorescence spectroscopy, that the greening of fabrics washed in optical brighteners is due to a reabsorption effect. The quantum yield of fluorescence of the optical brighteners OB15, OB36 and OB49 in water are 0.11 0.11 , 0.08 0.08 and 0.71 0.71 respectively. Their respective fluorescence natural lifetimes are 6700Ā±109 6700\pm109 , 5971Ā±712 5971\pm712 and 1685Ā±22 1685\pm22 ps. In solution, the excited state of OB15 experiences more competing relaxation processes as the solvatochromic shift increases. OB49 displays the opposite trend. A literature cellulose model surface is employed as a cotton mimic for evanescent wave fluorescence studies. Two model greases are similarly developed and used, and a third is presented for future work. These are based on surface-specific reactions with glass substrates, and the doping of a regenerated cellulose film with long chain alcohols. On doped cellulose surfaces, some low quantum yields occur compared to clean cellulose and bulk solution. Photobleaching behaviours are also observed. Both dyes physisorb rigidly to cellulose and grease models. The second part of this thesis identifies the pigment palette of the earliest Northumbrian manuscripts pre- and post-1066, by Raman and diffuse reflectance spectroscopy. It develops a suite of multispectral imaging programs in MATLAB for facile classification of pigments across a page ab initio, using data reduction and colour spaces. Raman and reflectance data are meta-analysed using symmetric permutation to split manuscripts and pigments into groups ab initio. It was also generalised, that the palette of the pre-Hastings selected manuscripts contained vergaut, indigo, orpiment, impure red lead, and copper green pigments, as well as orcein purples. Immediately post-1066 white lead, red ochre, vermilion and lapis lazuli appear in the palette in England, though vergaut and indigo disappear and the red lead used is essentially pure

    mĆ©thodologie de modĆ©lisation de la croissance de neurosphĆØres sous microscope Ć  contraste de phase

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    The study of stem cells is one of the most important fields of research in the biomedical field. Computer vision and image processing have been greatly emphasized in this area for the development of automated solutions for culture and observation of cells. This work proposes a new methodology for observing and modelling the proliferation of neural stem cell under a phase contrast microscope. At each time lapse observation performed by the microscope during the proliferation, the system determines a three-dimensional model of the structure formed by the observed cells. This is achieved by a framework combining analysis, synthesis and selection process. First, an analysis of the images from the microscope segments the neurosphere and the constituent cells. With this analysis, combined with prior knowledge about the cells and their culture protocol, several 3-D possible models are generated through a synthesis process. These models are finally selected and evaluated according to their likelihood with the microscope image using a 3-D to 2-D registration method. Through this approach, we present an automatic visualisation tool and observation of the proliferation of neural stem cell under a phase contrast microscope.L'Ć©tude des cellules souches est l'un des champs de recherches les plus importants dans le domaine biomĆ©dical. La vision par ordinateur et le traitement d'images ont Ć©tĆ© fortement mis en avant dans ce domaine pour le dĆ©veloppement de solutions automatiques de culture et d'observation de cellules. Ce travail de thĆØse propose une nouvelle mĆ©thodologie pour l'observation et la modĆ©lisation de la prolifĆ©ration de cellule souche neuronale sous microscope Ć  contraste de phase. ƀ chaque observation rĆ©alisĆ©e par le microscope durant la prolifĆ©ration, notre systĆØme extrait un modĆØle en trois dimensions de la structure de cellules observĆ©es. Cela est rĆ©alisĆ© par une suite de processus d'analyse, synthĆØse et sĆ©lection. PremiĆØrement, une analyse de la sĆ©quence d'images de contraste de phase permet la segmentation de la neurosphĆØre et des cellules la constituant. ƀ partir de ces informations, combinĆ©es avec des connaissances a priori sur les cellules et le protocole de culture, plusieurs modĆØles 3-D possibles sont gĆ©nĆ©rĆ©s. Ces modĆØles sont finalement Ć©valuĆ©s et sĆ©lectionnĆ©s par rapport Ć  lĀæimage dĀæobservation, grĆ¢ce Ć  une mĆ©thode de recalage 3-D vers 2-D. A travers cette approche, nous prĆ©sentons un outil automatique de visualisation et d'observation de la prolifĆ©ration de cellule souche neuronale sous microscope Ć  contraste de phase
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