A fingerprint matching algorithm with a novel set of matching parameters based on core points and triangular descriptors is proposed to discover rarity in fingerprints. The algorithm uses a mathematical and statistical approach to discover rare features in fingerprints which provides scientific validation for both ten-print and latent fingerprint evidence. A feature is considered rare if it is statistically uncommon; that is, the rare feature should be unique among N (N>100) randomly sampled prints. A rare feature in a fingerprint has higher discriminatory power when it is identified in a print (latent or otherwise). In the case of latent fingerprint matching, the enhanced discriminatory power from the rare features can help in delivering a confident court judgment. In addition to mining the rare features, a parallel algorithm for fingerprint matching on GPUs is also proposed to reduce the run-time of fingerprint matching on larger databases. Results show that 1) matching algorithm is useful in eliminating false matches. 2) each of the 30 fingerprints randomly selected to mine rare features have a small set of highly distinctive statistically rare features some of whose occurrence is one in 1000 fingerprints. 3) the parallel algorithm implemented on GPUs for larger databases is around 40 times faster than the sequential algorithm. / Master of Science

A method for determining the rare elements in bones and similar materials includes [eight] steps. / Master of Science

Ce travail se situe dans le cadre général de l'étude des nanostructures obtenues par mécanosynthèse qui font l'objet d'intenses recherches dans le domaine des aimants permanents de nouvelle génération et de l'enregistrement magnétique. L'objectif de l'étude du système Sm-Fe-Mo est de suivre l'effet de la substitut ion partielle du fer par le molybdène ainsi que l'effet de l'insertion d'un élément léger tel que le carbone sur leurs propriétés magnétiques afin d'établir une corrélation entre leur microstructure et leurs propriétés magnétiques. Nous avons montré que la mise en solution du molybdène est bien possible. La phase 2/17 ainsi obtenue possède une température de Curie (Tc) égale à 434K. Avec le taux de substitution croissant, on découvre un changement de phase vers une phase monoclinique 3/29 du type Nd3(Fe,Ti)29 de Tc égale à 459K, puis vers une structure quadratique (1/12 de Tc=551K). Ces phases d'équilibre, obtenues à haute température de recuit, dérivent toutes de la structure CaCu5. Elles correspondent à la substitution ordonnée des atomes de Sm par des haltères de Fe. A plus basse température de recuit, on découvre l'apparition de nouvelles phases, ne figurant pas dans les diagrammes d'équilibre. Nous avons déterminé les stchiométries respectives de ces phases par analyse des diagrammes de diffraction des RX par la technique de Rietveld. Ces phases hexagonales possèdent des propriétés magnétiques plus intéressantes que les phases d'équilibre. L'insertion du carbone change drastiquement les propriétés magnétiques des différentes phases / One important family among the hard magnetic rare-earth-transition-metal is derived from Sm-Fe-Mo CaCu5-type structure. The aim of the study of the system Sm-Fe-Mo is to follow the effect of partial substitution of Fe by Mo and the effect of the insertion of a light element such as carbon on their magnetic properties in order to correlate their microstructure and their magnetic properties.The ordered substitution of Sm atom by a dumbbell pair Fe-Fe leads to the equilibrium phases 2/17, 3/29 and 1/12 structure. With Mo content increase, a phase transformation is observed. The Curie temperatures of these phases are respectively 434, 459 and 551K. New phases are discovered to appear at lower annealing temperatures. Owing to Rietveld refinement, these phases crystallize in the P6/mmm structure. Carbon insertion improves drastically magnetic properties. The carbides of the new out of equilibrium phases are particularly promising for permanent magnet applications

Les désintégrations B->l l sont supprimées d'hélicité et se produisent à travers des courants neutres changeant la saveur. Elles sont donc extrêmement rares dans le modèle standard (MS). La physique au-delà du MS pourrait donc modifier substantiellement la valeur des rapports d'embranchement prédits par le MS. Ces prédictions étant très précises, mesurer leur valeurs constitue un test incontournable du MS.Les travaux présentés dans cette thèse ont contribué à l'établissement de la première évidence de la désintégration Bs->mu mu avec LHCb. Une méthode statistique a ete développée pour extraire et combiner les limites sur les rapports d'embranchement et calculer la signifiance des signaux. A partir de ces acquis statistiques, une méthode originale a été conçue pour re-optimiser les catégories dans lesquelles les candidats sont classés améliorant ainsi la sensibilité de l'analyse de 14%. D'autre part, une étude sur la phénoménologie des interférences entre le mélange de saveur des mésons Bs et leur désintégration a mis en évidence une subtile dépendance de l'analyse avec le modèle physique considéré. La prise en compte de cette dépendance permet de contraindre plus fortement la nouvelle physique. Enfin une méthode de reconstruction topologique inclusive des évènements a été développée et testée, notamment pour reconstruire les candidats Bs->tau tau avec tau->pi pi pi nu. / The B->l l decays are helicity suppressed and process through flavour changing neutral currents. They are extremely rare in the standard model (SM). Thus physics beyond SM could modify their branching ratio up to an observable level. As the theoretical predictions are very precise, these modes are golden channels to probe the SM.The works presented in this thesis have contributed to the establishment of the first evidence of the Bs->mu mu decay. A statistical method has been built to extract and combine limits on the decays branching fraction and to compute signals significance. On the basis of this work, an original method was developed to re-optimised the categories used to classified the candidates which improved the analysis sensitivity by 14%. A study of the interplay between the flavour mixing of the Bs and its decay demonstrated that the analysis results are model dependent. Accounting for this dependency allows to improve constraints on new physics. Finally, an inclusive topological reconstruction was developed and tested in particular to reconstruct Bs->tau tau candidates with tau->pi pi pi nu.

The power of the McCumber theory [D. E. McCumber, Phys. Rev. 136, A954-957 (1964)] consists in its ability to accurately predict emission cross section spectra from measured absorption, and vice versa, including both absolute values and spectral shapes. While several other theories only allow the determination of integrated cross sections, the McCumber theory is unique in generating the spectral shape of a cross section without any direct measurements regarding that cross section. The present work is a detailed study of the range of validity of the McCumber theory, focussing particularly on those aspects that most critically affect its applicability to transitions of rare earth ions in glasses. To analyze the effect of the spectral broadening on the accuracy of the technique, experiments were performed at room and low temperature. The theory was tested by comparing the cross sections calculated using the McCumber relation with those obtained from measurements. At room temperature, a number of ground state transitions of three different rare earth ions (Nd, Er and Tm) in oxide and fluoride glass hosts have been studied. Special attention was paid to the consistency of the measurements, using the same experimental setup, same settings and same detection system for both absorption and fluorescence measurements. Other aspects of the experimental procedure that could generate systematic errors, like fluorescence reabsorption and baseline subtraction uncertainties in the absorption measurements, were carefully investigated. When all these aspects are properly accounted for, we find in all cases an excellent agreement between the calculated and the measured cross section spectra. This suggests that the McCumber theory is not limited to crystalinne hosts, but describes quite well the reciprocity between emission and absorption for the broader transitions of rare earths in glassy hosts. This good agreement does not hold, however, for the low temperature results. The distortion observed in this case follows the theoretically predicted behavior, and corresponds to the amplification of the gaussian wings that describes the inhomogeneous type of broadening. Our results suggest that the McCumber theory must be used with caution for temperatures below 200 K.

The thermodynamic history of the Earth is preserved in the trace element record created through igneous processes. The ability to interpret that record depends on the accuracy and precision of numerical models that connect igneous processes with their geochemical consequences. This project answers three major questions concerning the relationship between trace element partitioning and the processes that influence it. One: using a common igneous mineral, clinopyroxene, as a base, how complete is the dataset on which our understanding of this relationship relies? Two: what are the dangers involved with basing models on experiments that contain higher than natural concentrations of trace elements? Three: how accurate and precise is the current numerical model that describes this relationship, and can it be improved? This project determined that the data contain gaps at high pressures and temperatures, are limited for felsic rock compositions, and are lacking for hydrous conditions. A set of experiments conducted on plagioclase feldspar crystallization from a base MORB composition containing various levels of dopants at below wt% levels reveals the presence of non-Henry's Law partitioning behavior through the disruption of the phase equilibria of the system. Lastly, the current clinopyroxene/melt rare earth element partitioning model (Wood and Blundy, 2003) is shown to reasonably, though less than ideally, describe the relationship between igneous processes and their trace-element partitioning results using the thermodynamics of the system. The accuracy was improved through adding a regression, which is based on the major element concentrations of the clinopyroxene and melt to the original numerical expressions. / Graduation date: 2012

A collection of >3000 MOFs with experimentally confirmed structures were screened for performance in three binary separations: Ar/Kr, Kr/Xe, and Xe/Rn. 70 materials were selected for further analysis, and calculations were performed to account for inaccessible regions. Single component GCMC calculations were performed to parameterize IAST calculations on these 70 materials, and the curve fitting problem in IAST was discussed. IAST calculations were confirmed with extensive binary GCMC calculations. For each binary separation, materials were identified with predicted performance that surpasses the state of the art. "Reverse selective" materials, for which a smaller gas species is preferably adsorbed over a larger species, were explained on the basis of surface fractal geometry, computed via a corrected surface area calculation. The effect of temperature on separation performance was also examined.

published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

Thesis (Ph. D.)--University of British Columbia, 1997. / Includes bibliographical references (leaves 127-133).

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