Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Spectral distances.
Дисертації з теми "Spectral distances"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "Spectral distances".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Godbout, Martin. "Mesures de distances et de spectres résolus en distance en utilisant les battements hétérodynes entre peignes de fréquences." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27451/27451.pdf.
Повний текст джерела
2
Imran, Hafiz Ali. "Remote Sensing Tools for Monitoring Grassland Plant Leaf Traits and Biodiversity." Doctoral thesis, Università degli studi di Trento, 2022. http://hdl.handle.net/11572/329592.
Повний текст джерелаАнотація:
Grasslands are one of the most important ecosystems on Earth, covering approximately one-third of the Earth’s surface. Grassland biodiversity is important as many services provided by such ecosystems are crucial for the human economy and well-being. Given the importance of grasslands ecosystems, in recent years research has been carried out on the potential to monitor them with novel remote sensing techniques. Improved detectors technology and novel sensors providing fine-scale hyperspectral imagery have been enabling new methods to monitor plant traits (PTs) and biodiversity.
The aims of the work were to study different approaches to monitor key grassland PTs such as Leaf Area Index (LAI) and biodiversity-related traits. The thesis consists of 3 parts: 1) Evaluating the performance of remote sensing methods to estimate LAI in grassland ecosystems, 2) Estimating plant biodiversity by using the optical diversity approach in grassland ecosystems, and 3) Investigating the relationship between PTs variability with alpha and beta diversity for the applicability of the optical diversity approach in a subalpine grassland of the Italian Alps
To evaluate the performance of remote sensing methods to estimate LAI, temporal and spatial observations of hyperspectral reflectance and LAI were analyzed at a grassland site in Monte Bondone, Italy (IT-MBo). In 2018, ground temporal observations of hyperspectral reflectance and LAI were carried out at a grassland site in Neustift, Austria (AT-NEU). To estimate biodiversity, in 2018 and 2019 a floristics survey was conducted to determine species composition and hyperspectral data were acquired at two grassland sites: IT-MBo and University of Padova’s Experimental Farm, Legnaro, Padua, Italy (IT-PD) respectively. Furthermore, in 2018, biochemistry analysis of the biomass samples collected from the grassland site IT-MBo was carried out to determine the foliar biochemical PTs variability.
The results of the thesis demonstrated that the grassland spectral response across different spectral regions (Visible: VIS, red-edge: RE, Near-infrared: NIR) showed to be both site-specific and scale-dependent. In the first part of the thesis, the performance of spectral vegetation indices (SVIs) based on visible, red-edge (RE), and NIR bands alongside SVIs solely based or NIR-shoulder bands (wavelengths 750 - 900 nm) was evaluated. A strong correlation (R2 > 0.8) was observed between grassland LAI and both RE and NIR-shoulder SVIs on a temporal basis, but not on a spatial basis. Using the PROSAIL Radiative Transfer Model (RTM), it was demonstrated that grassland structural heterogeneity strongly affects the ability to retrieve LAI, with high uncertainties due to structural and biochemical PTs co-variation.
In the second part, the applicability of the spectral variability hypothesis (SVH) was questioned and highlighted the challenges to use high-resolution hyperspectral images to estimate biodiversity in complex grassland ecosystems. It was reported that the relationship between biodiversity (Shannon, Richness, Simpson, and Evenness) and optical diversity metrics (Coefficient of variation (CV) and Standard deviation (SD)) is not consistent across plant communities. The results of the second part suggested that biodiversity in terms of species richness could be estimated by optical diversity metrics with an R2 = 0.4 at the IT-PD site where the grassland plots were artificially established and are showing a lower structure and complexity from the natural grassland plant communities. On the other hand, in the natural ecosystems at IT-MBo, it was more difficult to estimate biodiversity indices, probably due to structural and biochemical PTs co-variation. The effects of canopy non-vegetative elements (flowers and dead material), shadow pixels, and overexposed pixels on the relationship between optical diversity metrics and biodiversity indices were highlighted.
In the third part, we examined the relationship between PTs variability (at both local and community scales, measured by standard deviation and by the Euclidean distances of the biochemical and biophysical PTs respectively) and taxonomic diversity (both α-diversity and β-diversity, measured by Shannon’s index and by Jaccard dissimilarity index of the species, families, and functional groups percent cover respectively) in Monte Bondone, Trentino province, Italy. The results of the study showed that the PTs variability metrics at alpha scale were not correlated with α-diversity. However, the results at the community scale (β-diversity) showed that some of the investigated biochemical and biophysical PTs variations metrics were associated with β-diversity. The SVH approach was also tested to estimate β-diversity and we found that spectral diversity calculated by spectral angular mapper (SAM) showed to be a better proxy of biodiversity in the same ecosystem where the spectral diversity failed to estimate alpha diversity, this leading to the conclusion that the link between functional and species diversity may be an indicator of the applicability of optical sampling methods to estimate biodiversity.
The findings of the thesis highlighted that grassland structural heterogeneity strongly affects the ability to retrieve both LAI and biodiversity, with high uncertainties due to structural and biochemical PTs co-variation at complex grassland ecosystems. In this context, the uncertainties of satellite-based products (e.g., LAI) in monitoring grassland canopies characterized by either spatially or temporally varying structure need to be carefully taken into account. The results of the study highlighted that the poor performance of optical diversity proxies in estimating biodiversity in structurally heterogeneous grasslands might be due to the complex relationships between functional diversity and biodiversity, rather than the impossibility to detect functional diversity with spectral proxies.
3
Deborah, Hilda. "Towards spectral mathematical morphology." Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2328/document.
Повний текст джерелаАнотація:
En fournissant en plus de l'information spatiale une mesure spectrale en fonction des longueurs d'ondes, l'imagerie hyperspectrale s'enorgueillie d'atteindre une précision bien plus importante que l'imagerie couleur. Grâce à cela, elle a été utilisée en contrôle qualité, inspection de matériaux,… Cependant, pour exploiter pleinement ce potentiel, il est important de traiter la donnée spectrale comme une mesure, d'où la nécessité de la métrologie, pour laquelle exactitude, incertitude et biais doivent être maitrisés à tous les niveaux de traitement.Face à cet objectif, nous avons choisi de développer une approche non-linéaire, basée sur la morphologie mathématique et de l'étendre au domaine spectral par le biais d'une relation d'ordre spectral basée sur les fonctions de distance. Une nouvelle fonction de distance spectrale et une nouvelle relation d'ordonnancement sont ainsi proposées. De plus, un nouvel outil d'analyse du basé sur les histogrammes de différences spectrales a été développé.Afin d'assurer la validité des opérateurs, une validation théorique rigoureuse et une évaluation métrologique ont été mises en œuvre à chaque étage de développement. Des protocoles d'évaluation de la qualité des traitements morphologiques sont proposés, exploitant des jeux de données artificielles pour la validation théorique, des ensembles de données dont certaines caractéristiques sont connues pour évaluer la robustesse et la stabilité et des jeux de données de cas réel pour prouver l'intérêt des approches en contexte applicatif. Les applications sont développées dans le contexte du patrimoine culturel pour l'analyse de peintures et pigmentsProviding not only spatial information but also spectral measure as a function of wavelength, hyperspectral imaging boasts a much greater gain in accuracy than the traditional color imaging. And for this capability, hyperspectral imaging has been employed for quality control, inspection of materials in various fields. However, to fully exploit this potential, it is important to process the spectral data as a measure. This induces the need of metrology where accuracy, uncertainty, and bias are managed at every level of processing.Aiming at developing a metrological image processing framework for spectral data, we select to develop a nonlinear approach using the mathematical morphology framework and extended it to the spectral domain by means of a distance-based ordering relation. A novel spectral distance function and spectral ordering relation are proposed, in addition of a new analysis tools based on spectral differences. To ensure the validity of the spectral mathematical morphology framework, rigorous theoretical validation and metrological assessment are carried out at each development stages. So, protocols for quality assessment of spectral image processing tools are developed. These protocols consist of artificial datasets to validate completely the theoretical requirements, datasets with known characteristics to assess the robustness and stability, and datasets from real cases to proof the usefulness of the framework on applicative context. The application tasks themselves are within the cultural heritage domain, where the target images come from pigments and paintings
Hyperspektral avbildning muliggjør mye mer nøyaktige målinger enn tradisjonelle gråskala og fargebilder, gjennom både høy romlig og spektral oppløsning (funksjon av bølgelengde). På grunn av dette har hyperspektral avbildning blitt anvendt i økende grad ulike applikasjoner som kvalitetskontroll og inspeksjon av materialer. Men for å fullt ut utnytte sitt potensiale, er det viktig å være i stand til å behandle spektrale bildedata som målinger på en gyldig måte. Dette induserer behovet for metrologi, der nøyaktighet, usikkerhet og skjevhet blir adressert og kontrollert på alle nivå av bildebehandlingen.Med sikte på å utvikle et metrologisk rammeverk for spektral bildebehandling valgte vi en ikke-lineær metodikk basert på det etablerte matematisk morfologi-rammeverket. Vi har utvidet dette rammeverket til det spektrale domenet ved hjelp av en avstandsbasert sorteringsrelasjon. En ny spektral avstandsfunksjon og nye spektrale sorteringsrelasjoner ble foreslått, samt nye verktøy for spektral bildeanalyse basert på histogrammer av spektrale forskjeller.For å sikre gyldigheten av det nye spektrale rammeverket for matematisk morfologi, har vi utført en grundig teoretisk validering og metrologisk vurde-ring på hvert trinn i utviklingen. Dermed er og-så nye protokoller for kvalitetsvurdering av spektrale bildebehandlingsverktøy utviklet. Disse protokollene består av kunstige datasett for å validere de teoretiske måletekniske kravene, bildedatasett med kjente egenskaper for å vurdere robustheten og stabiliteten, og datasett fra reelle anvendelser for å bevise nytten av rammeverket i en anvendt sammenheng. De valgte anvendelsene er innenfor kulturminnefeltet, hvor de analyserte bildene er av pigmenter og malerier
4
Bertrand, Jérôme. "Pincement spectral en courbure positive." Paris 11, 2003. https://tel.archives-ouvertes.fr/tel-00008705.
Повний текст джерелаАнотація:
Sur l'ensemble des variétés Riemanniennes compactes à courbure de Ricci positive (on normalise par Ric ≥ (n -1)g), la première valeur propre du Laplacien agissant sur les fonctions atteint son minimum uniquement pour la sphère canonique. Dans cette thèse, nous caractérisons, à l'aide de la distance de Gromov-Hausdorff, les variétés Riemanniennes à courbure positive dont les premières valeurs propres du Laplacien sont proches de celles de la sphère canonique. Cette propriété de minimimalité du spectre de la sphère s'étend par un procédé de symétrisation, au spectre de Dirichlet des boules géodésiques de la sphère parmi les domaines de variétés à courbure de Ricci positive. Nous étudions les domaines de variétés à courbure de Ricci positive dont la première valeur propre de Dirichlet est presque minimale. En particulier, nous montrons qu'un domaine dont la première valeur propre de Dirichlet est proche de celle d'un hémisphère est Gromov-Hausdorff proche d'un hémisphère d'un sinus produit torduOn the set of compact Riemannian manifolds with positive Ricci curvature (normalized by Ric ≥ (n-1)g), the first eigenvalue of the Laplacian acting on functions reaches its minimum only for the round sphere. In this thesis, we characterize, using the Gromov-Hausdorff distance, Riemannian manifolds with positive Ricci curvature whose first eigenvalues are close to those of the round sphere. This property of minimality of the spectrum of the round sphere has been extended by a symmetrization principle, to the Dirichlet spectrum of the geodesic balls of the round sphere among the domains of Riemannian manifolds with positive curvature. We study the domains of Riemannian manifolds with positive Ricci curvature whose first Dirichlet eigenvalue is almost minimal. In particular, we show that a domain whose first Dirichlet eigenvalue is close to the one of a hemisphere is Gromov-Hausdorff close to a hemisphere of a sine warped product
5
Diego, Víctor. "On some spectral and combinatorial properties of distance-regular graphs and their generalizations." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/461632.
Повний текст джерелаАнотація:
In this work we present the study we did in Graph Theory. In the firsts chapteres of the tesis we study the pieces of information that can be obtained from a graph: the spectrum of the adjacency matrix, the preintersection numbers, the predistance polynomials and the average number of closed walks. Some of this pieces of information are direct generalizations of the intersection numbers or the predistance polynomials defined in the distance-regular graphs. We prove that the multiple properties that these pieces of information have in distance-regular graphs hold also in their generalizations, and these properties can be applied to any other graph.
We also prove that the distinct pieces of information (even if their nature is algebraic or combinatorial) are equivalent. That is, we can obtain each one of the pieces in terms of each other; proving in this way that the properties of the graph derived from each one of the pieces can be also obtained in terms of each one of the other. We dedicate a chapter of the tesis to describe completly the especific procedures with which obtain each piece of inforation in terms of the others.
In this tesis we introduce the "distance mean-regular" graphs. These graphs are a generalization of the distance-regular graphs. In this occasion, we demand to the graph combinatorial properties and we generalizate the algebraic properties of the distance-regular graphs. We generalizate the spectrum of a graph to introduce the "pseudo-spectrum" and we generalizate the Bose-Mesner algebra in distinct matrix algebras. The study of these generalizations, as well as the study of the relation between them, give us combinatorial and algebraic properties.
In the final part of the tesis we study the vertex-isoperimetric problem in the Johnson Graph J(n,m). We solve completly the problem for some particular cases: J(n,1), J(n,2), J(2m-2,m), as well as their symetrics J(n,n-2) and J(2m+2,m). The solution for these cases are the initial segments of the colexicographic order. This order is also the solution for small cardinals in every graph of this family, as well as for the asymptotic behaviour of the parameters n and m.
However, this solution is not the optimal solution for every cardinal in every graph J(n,m). We prove and give an infinity family of counterexamples for which the initial segment of the colexicographic order is not optimal in terms of the vertex-isoperimetric problem.En este documento presentamos el estudio realizado en Teoría de Grafos. En los primeros capítulos de la tesis estudiamos las distinetas piezas de información que se pueden obtener de un grafo: el espectro de su matriz de adyacencia, los números de preintersección, los polinomios predistancia o la cantidad media de caminos cerrados. Algunos de estas piezas de información son generalizaciones directas de los números de intersección o los pollinomios distancia definidos en los grafos distancia-regulares. Demostramos que las múltiples propiedades que tienen estas piezas de información en los grafos distancia-regulares se mantienen también en sus generalizaciones, pudiendo aplicar estas propiedades a todo tipo de grafos. Demostramos también que las ditintas piezas de información (ya sean de naturaleza algebraica o combinatoria) son equivalentes. Es decir, podemos obtener cada una de estas piezas en términos de cada una de las otras; probando así que las propiedades del grafo derivadas de cada una de estas piezas puede ser obtenida en términos de cada una de las otras. Dedicamos uno de los capítulos de la tesis a describir cuáles son los procesos específicos completos mediante los cuales obtener cada pieza de información en función de las otras. En esta tesis introducimos también los grafos distance mean-regular. Estos grafos son una generalización de los grafos distancia-regulares. En esta ocasión, al grafo se le exigen propiedades combinatorias y generalizamos las propiedades algebraicas de los grafos distancia-regulares. Generalizamos el espectro de un grafo para introducir el "pseudo-espectro" y generalizamos el álgebra de Bose-Mesner en distintas álgebras de matrices. El estudio de estas generalizaciones, así cómo su relación entre ellas nos proporciona propiedades combinatorias y algebraicas del grafo. En la parte final de la tesis estudiamos el problema isoperimétrico de vértices en el Grafo de Johnson J(n,m). Solucionamos el problema completamente para varios casos particulares: J(n,1), J(n,2) y J(2m-2,m), así como sus simétricos J(n,n-2) y J(2m+2,m). La solución para estos casos son los segmentos iniciales del orden colexicográfico. Este orden es también la solución para cardinales pequeños en todos los grafos de esta familia, así como para el comportamiento asimptótico de los parámetros n y m. Sin embargo, esta solución no es la solución óptima en todos cardinales de todos los grafos J(n,m). Demostramos y damos una familia infinita de contraejemplos para los cuales el segmento inicial de orden colexicográfico no es óptimo en términos del problema isoperimétrico de vértices
6
Taylor, Melinda Marie. "Analysis of Cepheid Spectra." Thesis, The University of Sydney, 1998. http://hdl.handle.net/2123/388.
Повний текст джерелаАнотація:
Using high resolution optical spectra from Mount John University Observatory, Mount Stromlo Observatory and the Anglo-Australian Observatory, new, high accuracy radial velocity curves have been obtained for the two bright southern Cepheids l carinae (HR 3884) and beta doradus (HR 1922). An indepth investigation into period variations, cycle-to-cycle and long-term variations in the velocity curves and the reliability of the combination of velocity data from different observatories is carried out. Evidence for shock waves in the atmosphere of l car and resonance in beta dor is discussed. A grid of static model atmospheres incorporating plane-parallel geometry is compared with the observational spectra of both Cepheids, using line depth ratios, to determine the variation in effective temperature, surface gravity and microturbulence with phase. This information is used to determine the phase dependence of the surface-brightness for both Cepheids. The surface brightness variation with phase was found to follow an almost linear relationship. The distance to and radius of the Cepheids are determined using both a near-infrared version of the Barnes-Evans method and the Fourier Baade-Wesselink (BW) method. The derived radii and distances agree within the limits of the errors for both methods. The Fourier BW method was found to be very sensitive to phase shifts between the photometric and spectroscopic data and the derived distance highly dependent on the assumed reddening. An investigation into line profile variations in l car and beta dor has revealed the magnitude of these phenomena increase as the pulsational period of the Cepheid increases. It is estimated that line level variations introduce an additional uncertainty into derived radii of approximately 4 per cent for beta dor and 10 per cent in lcar. The uncertainty introduced into derived distances and radii by line profile asymmetries was estimated to be of the order of 6 per cent in beta dor and 10 per cent in l car. A comparative analysis is made of the hydrogen line radial velocity curves of l car and beta dor. A trend in the properties of these radial velocity curves with period has been revealed. In longer period Cepheids, the Halpha line seems to be forming in a region that does not partake in the pulsation as a whole, probably in a chromospheric shell. A quantitative analysis of the asymmetries in these lines reveal large redward asymmetries near maximum infall velocity. The magnitude of these asymmetries and the period for which they are present are larger in l Car than in beta dor. The blueward asymmetries in the Halpha line in l Car are comparable in magnitude to the redward asymmetries while the other lines exhibit only small blueward asymmetries. A qualitative analysis of these line profiles with phase reveal no conclusive evidence for line doubling in these Cepheids. Evidence of emission is found in the Halpha and H Beta lines of beta dor and l car. The strength and duration of the emission is found to be greater in the longer period Cepheid. Although it is likely that this emission is shock-related, theoretical work is needed to determine the exact origin of the emission. A non-LTE radiative hydrodynamic model for l Car has been created. This atmosphere will be used in further work to calculate synthetic spectral line profiles which will aid the interpretation of our observational results.
7
Taylor, Melinda Marie. "Analysis of Cepheid Spectra." University of Sydney, Physics, 1998. http://hdl.handle.net/2123/388.
Повний текст джерелаАнотація:
Using high resolution optical spectra from Mount John University Observatory, Mount Stromlo Observatory and the Anglo-Australian Observatory, new, high accuracy radial velocity curves have been obtained for the two bright southern Cepheids l carinae (HR 3884) and beta doradus (HR 1922). An indepth investigation into period variations, cycle-to-cycle and long-term variations in the velocity curves and the reliability of the combination of velocity data from different observatories is carried out. Evidence for shock waves in the atmosphere of l car and resonance in beta dor is discussed. A grid of static model atmospheres incorporating plane-parallel geometry is compared with the observational spectra of both Cepheids, using line depth ratios, to determine the variation in effective temperature, surface gravity and microturbulence with phase. This information is used to determine the phase dependence of the surface-brightness for both Cepheids. The surface brightness variation with phase was found to follow an almost linear relationship. The distance to and radius of the Cepheids are determined using both a near-infrared version of the Barnes-Evans method and the Fourier Baade-Wesselink (BW) method. The derived radii and distances agree within the limits of the errors for both methods. The Fourier BW method was found to be very sensitive to phase shifts between the photometric and spectroscopic data and the derived distance highly dependent on the assumed reddening. An investigation into line profile variations in l car and beta dor has revealed the magnitude of these phenomena increase as the pulsational period of the Cepheid increases. It is estimated that line level variations introduce an additional uncertainty into derived radii of approximately 4 per cent for beta dor and 10 per cent in lcar. The uncertainty introduced into derived distances and radii by line profile asymmetries was estimated to be of the order of 6 per cent in beta dor and 10 per cent in l car. A comparative analysis is made of the hydrogen line radial velocity curves of l car and beta dor. A trend in the properties of these radial velocity curves with period has been revealed. In longer period Cepheids, the Halpha line seems to be forming in a region that does not partake in the pulsation as a whole, probably in a chromospheric shell. A quantitative analysis of the asymmetries in these lines reveal large redward asymmetries near maximum infall velocity. The magnitude of these asymmetries and the period for which they are present are larger in l Car than in beta dor. The blueward asymmetries in the Halpha line in l Car are comparable in magnitude to the redward asymmetries while the other lines exhibit only small blueward asymmetries. A qualitative analysis of these line profiles with phase reveal no conclusive evidence for line doubling in these Cepheids. Evidence of emission is found in the Halpha and H Beta lines of beta dor and l car. The strength and duration of the emission is found to be greater in the longer period Cepheid. Although it is likely that this emission is shock-related, theoretical work is needed to determine the exact origin of the emission. A non-LTE radiative hydrodynamic model for l Car has been created. This atmosphere will be used in further work to calculate synthetic spectral line profiles which will aid the interpretation of our observational results.
8
Bertrand, Jerome. "Pincement spectral en courbure positive." Phd thesis, Université Paris Sud - Paris XI, 2003. http://tel.archives-ouvertes.fr/tel-00008705.
Повний текст джерелаАнотація:
Sur l'ensemble des variétés riemanniennes compactes à courbure de Ricci positive (on normalise par $Ric \geq (n-1)g$), la première valeur propre non nulle du laplacien agissant sur les fonctions atteint son minimum uniquement pour la sphère canonique. Dans cette thèse, nous caractérisons, à l'aide de la distance de Gromov-Hausdorff, les variétés riemanniennes à courbure positive dont les premières valeurs propres du laplacien sont proches de celles de la sphère canonique. Cette propriété de minimimalité du spectre de la sphère s'étend par un procédé de symétrisation, au spectre de Dirichlet des boules géodésiques de la sphère parmi les domaines de variétés à courbure de Ricci positive. Nous étudions les domaines de variétés à courbure de Ricci positive dont la première valeur propre de Dirichlet est presque minimimale. En particulier, nous montrons qu'un domaine convexe dont la première valeur propre de Dirichlet est proche de celle d'un hémisphèere est Gromov-Hausdorff proche d'un hémisphère d'un sinus produit tordu.
9
Harrell, Dameon C. (Dameon Cartíer) 1976. "Effects of microphone type and distance upon the spectra of speech sounds." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80067.
Повний текст джерелаАнотація:
Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1999.Includes bibliographical references (leaf 71).
by Dameon C. Harrell.
S.B.and M.Eng.
10
Cerocchi, Filippo. "Dynamical and Spectral applications of Gromov-Hausdorff Theory." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENM077/document.
Повний текст джерелаАнотація:
Cette thèse est divisée en deux parties. La première est consacrée à la méthode du barycentre, introduite en 1995 par G. Besson, G. Courtois et S. Gallot pour résoudre la conjecture de l'Entropie Minimale. Dans le Chapitre 1 nous décrivons ses développements les plus récents, notamment l'extension de cette méthode au cadre des variétés dont la courbure sectionnelle est de signe quelconque (voir les énoncés 1.2.1 et 1.4.1). Dans le Chapitre 2 et 3 nous présentons des résultats dans lesquels la méthode du barycentre joue un rôle important. Le problème “deux variétés dont les flots géodésiques sont conjugués sont-elles isométriques ?” (problème de la rigidité par conjugaison des flots) est le thème du Chapitre 2. Après avoir montré que deux telles variétés ont la même géométrie à grande échelle, on montre comment on peut utiliser ce résultat et la méthode du barycentre pour donner une nouvelle preuve de la rigidité (par conjugaison des flots) des variétés plates. Dans le Chapitre 3 nous utilisons la méthode du barycentre (en courbure de signe quelconque) et des inégalités de Sobolev itérées pour démontrer un théorème de comparaison entre les spectres de deux variétés riemanniennes (Y , g) et (X , g') de volumes proches, sachant qu'il existe une approximation de Gromov-Hausdorff de degré non nul entre ces deux variétés. Il s'agit d'un résultat d'approximation avec majoration de l'erreur d'approximation (et pas seulement d'un résultat de convergence). Remarquons qu'il n'est fait aucune autre hypothèse géométrique (et en particulier aucune hypothèse de courbure) sur la variété (Y , g), ce qui autorise un grand nombre de contre-exemples prouvant que le résultat est optimal. Dans la deuxième partie de la thèse (chapitre 4), on démontre un Lemme de Margulis sans hypothèse sur la courbure, qui s'applique aux variétés dont les groupes fondamentaux sont des produits libres (et qui ne possèdent pas d'élément de torsion d'ordre 2). Nous donnons également une borne inférieure de la systole des variétés dont le diamètre et l'entropie volumique sont majorés et dont le groupe fondamental est isomorphe à un produit libre sans torsion. Comme conséquences de ce dernier résultat nous obtenons des résultats de précompacité et de finitude topologique ou différentiable pour les variétés riemanniennes et une minoration de leur volume, tout ceci sans faire d'hypothèse de courbureThis Ph.D. Thesis is divided into two parts. In the first part we present the barycenter method, a technique which has been introduced by G. Besson, G. Courtois and S. Gallot in 1995, in order to solve the Minimal Entropy conjecture. In Chapter 1 we are interested in the more recent developments of this method, more precisely in the recent extension of the method to the case of manifolds having sectional curvature of variable sign. In Chapters 2 and 3 we shall present some new results whose proofs make use of the barycenter method. The Conjugacy Rigidity problem is the theme of Chapter 2. First we show a general result which provide a comparison between the large scale geometry of the Riemannian universal coverings of two compact manifolds whose geodesic flows are conjugates. Then we shall show how we can apply the latter result and the barycenter method in curvature of variable sign in order to give a new proof of the conjugacy rigidity of flat manifolds. In Chapter 3 we shall give a proof of a spectra comparison theorem for a compact Riemannian manifold which admits a Gromov-Hausdorff-approximation of non zero absolute degree on a fixed compact manifold (X,g') and which has volume almost smaller than the one of the reference manifold. The proof relies on the barycenter method in curvature of variable sign and on iterated Sobolev inequalities. We underline that it is an approximation result (and not just a convergence result) and that no curvature assumptions are made or inferred on (Y,g). The second part of the Thesis consists of a single chapter. In this chapter we prove a Margulis Lemma without curvature assumptions for Riemannian manifolds having decomposable 2-torsionless fundamental group. We shall give also a proof of a universal lower bound for the homotopy systole of compact Riemannian manifolds having bounded volume entropy and diameter, and decomposable torsionless fundamental group. As a consequence of the latter result we shall deduce a Precompactness and Finiteness theorem and a Volume estimate without curvature assumptions
11
Cagnache, Eric. "Aspects différentiels et métriques de la géométrie non commutative : application à la physique." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112115.
Повний текст джерелаАнотація:
La géométrie non commutative, du fait qu'elle permet de généraliser des objets géométriques sous forme algébrique, offre des perspectives intéressantes pour réunir la théorie quantique des champs et la relativité générale dans un seul cadre. Elle peut être abordée selon différents points de vue et deux d'entre eux sont présentés dans cette thèse. Le premier, le calcul différentiel basé sur les dérivations, nous a permis de construire une action de Yang-Mills-Higgs dans laquelle apparait des champs pouvant être interprétés comme des champs de Higgs. Avec le second, les triplets spectraux, on peut généraliser la notion de distance entre état et calculer des formules de distance. C'est ce que nous avons fait dans le cas de l'espace de Moyal et du tore non commutatifNoncommutative geometry offers interesting prospects to gather the quantum field theory and relativity in one general framework because it allows one to generalize geometric objects algebraically. It can be approached from different points of view and two of them are presented in this PhD. The first, calculus based on derivations, allowed us to construct a Yang-Mills-Higgs action which appears in fields that can be interpreted as Higgs fields. With the second, spectral triples, we can generalize the notion of distance between states. We calculated the distance formulas in the case of the Moyal space and the noncommutative torus
12
Dougall, Rhiannon. "Critical exponents, the spectrum of group extended transfer operators and Kazhdan distance." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/95546/.
Повний текст джерела
13
Liang, Hongkang. "Statistics of nonlinear averaging spectral estimators and a novel distance measure for HMMs with application to speech quality estimation." Laramie, Wyo. : University of Wyoming, 2005. http://proquest.umi.com/pqdweb?did=1031050291&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Повний текст джерела
14
Dobroc, Alexandre. "Etude et réalisation de dispositifs optiques à large couverture spectrale pour la détection multi-gaz à distance." Phd thesis, Ecole Polytechnique X, 2013. http://pastel.archives-ouvertes.fr/pastel-00959752.
Повний текст джерелаАнотація:
Les travaux de thèse présentés dans ce manuscrit ont pour objectifs l'étude et la mise en oeuvre de nouvelles techniques actives de spectroscopie d'absorption infrarouge pour la détection multi-gaz à distance. Pour cette application, nous avons étudié le potentiel de deux sources laser innovantes : un Oscillateur Paramétrique Optique Doublement Résonnant (DROPO), émettant un rayonnement monochromatique accordable entre 3,3µm et 3,7µm et un laser fibré Supercontinuum, émettant un spectre continu s'étendant de 1µm jusquau-delà de 3,8µm. Après avoir modélisé les signaux ainsi que le bruit, nous avons calculé les performances théoriques d'estimation de concentration à l'aide des Bornes de Cramer-Rao (BCR). Puis, nous avons développé des estimateurs de concentrations multi-gaz adaptés aux caractéristiques des signaux DROPO et Supercontinuum. Ces estimateurs ont été appliqués à des signaux expérimentaux dans le but de valider le calcul des prévisions de performances. Dans le cas de la spectroscopie par DROPO, des mesures simultanées des concentrations en vapeur d'eau et en méthane, intégrées sur un trajet de 30m dans l'atmosphère ont été réalisées (après diffusion sur une cible non coopérative). Dans le cas de la spectroscopie Supercontinuum, nous avons réalisé un premier montage basé sur une source proche infrarouge et un analyseur de spectre commerciaux afin de valider le traitement du signal ainsi que la prédiction de performances. Nous avons réalisé des mesures simultanées de la quantité de méthane présente dans une cellule et la concentration atmosphérique en vapeur d'eau intégrée sur une distance de plus de 10m (par réflexion sur une cible coopérative). L'estimation est non biaisée et l'écart type calculé sur un grand nombre d'estimations est inférieur à 1, 5 fois les BCR. Pour les expériences de spectroscopie réalisées autour de 3,3µm, nous avons adapté, implémenté et calibré un spectrographe permettant d'acquérir en quelques secondes une centaine de spectres sur un domaine spectral de200nm, avec une résolution inférieure au nanomètre. Un estimateur du maximum de vraisemblance a fourni une estimation peu biaisée (3%) avec un écart type égal à 2, 5 fois la BCR. Nous avons ainsi montré expérimentalement la faisabilité de mesures rapides et précises par spectroscopie Supercontinuum infrarouge.
15
Chen, Brenden Chong. "Robust image hash functions using higher order spectra." Thesis, Queensland University of Technology, 2012. https://eprints.qut.edu.au/61087/1/Brenden_Chen_Thesis.pdf.
Повний текст джерелаАнотація:
Robust hashing is an emerging field that can be used to hash certain data types in applications unsuitable for traditional cryptographic hashing methods. Traditional hashing functions have been used extensively for data/message integrity, data/message authentication, efficient file identification and password verification.
These applications are possible because the hashing process is compressive, allowing for efficient comparisons in the hash domain but non-invertible meaning hashes can be used without revealing the original data. These techniques were developed with deterministic (non-changing) inputs such as files and passwords.
For such data types a 1-bit or one character change can be significant, as a result the hashing process is sensitive to any change in the input. Unfortunately, there are certain applications where input data are not perfectly deterministic and minor changes cannot be avoided. Digital images and biometric features are two types of data where such changes exist but do not alter the meaning or appearance of the input. For such data types cryptographic hash functions cannot be usefully applied.
In light of this, robust hashing has been developed as an alternative to cryptographic hashing and is designed to be robust to minor changes in the input.
Although similar in name, robust hashing is fundamentally different from cryptographic hashing. Current robust hashing techniques are not based on cryptographic methods, but instead on pattern recognition techniques. Modern robust hashing algorithms consist of feature extraction followed by a randomization stage that introduces non-invertibility and compression, followed by quantization and binary encoding to produce a binary hash output. In order to preserve robustness of the extracted features, most randomization methods are linear and this is detrimental to the security aspects required of hash functions. Furthermore, the quantization and encoding stages used to binarize real-valued features requires the learning of appropriate quantization thresholds. How these thresholds are learnt has an important effect on hashing accuracy and the mere presence of such thresholds are a source of information leakage that can reduce hashing security.
This dissertation outlines a systematic investigation of the quantization and encoding stages of robust hash functions. While existing literature has focused on the importance of quantization scheme, this research is the first to emphasise the importance of the quantizer training on both hashing accuracy and hashing security. The quantizer training process is presented in a statistical framework which allows a theoretical analysis of the effects of quantizer training on hashing performance. This is experimentally verified using a number of baseline robust image hashing algorithms over a large database of real world images.
This dissertation also proposes a new randomization method for robust image hashing based on Higher Order Spectra (HOS) and Radon projections. The method is non-linear and this is an essential requirement for non-invertibility.
The method is also designed to produce features more suited for quantization and encoding. The system can operate without the need for quantizer training, is more easily encoded and displays improved hashing performance when compared to existing robust image hashing algorithms. The dissertation also shows how the HOS method can be adapted to work with biometric features obtained from 2D and 3D face images.
16
Demarco, Ricardo. "Propriétés physiques et évolution des Baryons dans les amas de galaxies proches et distants." Paris 7, 2003. http://www.theses.fr/2003PA077241.
Повний текст джерела
17
Rosenberger, Elke. "Asymptotic spectral analysis and tunnelling for a class of difference operators." Phd thesis, [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=98050368X.
Повний текст джерела
18
Wu, Haitao. "Conception et analyse d’algorithmes d’approximation dans les réseaux de communication de nouvelle génération." Thesis, Avignon, 2018. http://www.theses.fr/2018AVIG0231/document.
Повний текст джерелаАнотація:
Avec l’avènement de l’ère intellectuelle et de l’Internet of Everything (IoE), les besoins de la communication mondiale et des applications diverses ont explosé. Cette révolution exige que les futurs réseaux de communication soient plus efficaces, intellectuels, agiles et évolutifs. De nombreuses technologies réseau sont apparues pour répondre à la tendance des réseaux de communication de nouvelle génération tels que les réseaux optiques élastiques (EONs) et la virtualisation de réseau. De nombreux défis apparaissent avec les apparences de la nouvelle architecture et de la nouvelle technologie, telles que le routage et l’allocation de ressource spectrale (RSA) dans les EONs et l’intégration de réseaux virtuels (Virtual Network Embedding ou VNE) dans la virtualisation de réseau.Cette thèse traite la conception et l’analyse d’algorithmes d’approximation dans trois problèmes d’optimation du RSA et du VNE : les impacts de la distribution du trafic et de la topologie du réseau sur le routage tout optique, de l’allocation de ressource spectrale, et du VNE dans les topologies des chemins et cycles. Pour le routage tout optique, le premier sous-problème du RSA, il y a toujours un problème en suspens concernant l’impact de la distribution du trafic et de la topologie EON. Comme le routage tout optique joue un rôle essentiel pour la performance globale de la RSA, cette thèse fournit une analyse approfondi théorique sur ces impacts. Pour le deuxième sous-problème du RSA, l’allocation de ressource spectrale, deux chemins optiques quelconques partageant des fibres optiques communes pourraient devoir être isolés dans le domaine spectral avec une bande de garde appropriée pour empêcher la diaphonie et / ou réduire les menaces de sécurité de la couche physique. Cette thèse considère le scénario dans lequel les exigences de bandes de garde réelles optiques sont différentes pour différentes paires de chemins, et étudie comment affecter les ressources spectrales efficacement dans une telle situation. L’hétérogénéité de la topologie des demandes de réseau virtuel (VNR) est un facteur important qui entrave les performances de la VNE. Cependant, dans de nombreuses applications spécialisées, les VNR ont des caractéristiques structurelles communes par exemple, des chemins et des cycles. Pour obtenir de meilleurs résultats, il est donc essentiel de concevoir des algorithmes dédiés pour ces applications en tenant compte des caractéristiques topologiques. Dans cette thèse, nous prouvons que les problèmes VNE dans les topologies de chemin et de cycle sont NP-difficiles. Afin de les résoudre, nous proposons des algorithmes efficaces également analysons leurs ratios d’approximationWith the coming of intellectual era and Internet of Everything (IoE), the needs of worldwide communication and diverse applications have been explosively growing. This information revolution requires the future communication networks to be more efficient, intellectual, agile and scalable. Many technologies have emerged to meet the requirements of next generation communication networks such as Elastic Optical Networks (EONs) and networking virtualization. However, there are many challenges coming along with them, such as Routing and Spectrum Assignment (RSA) in EONs and Virtual Network Embedding (VNE) in network virtualization. This dissertation addresses the algorithm design and analysis for these challenging problems: the impacts of traffic distribution and network topology on lightpath routing, the distance spectrum assignment and the VNE problem for paths and cycles.For lightpath routing, the first subproblem of the RSA, there is always a pending issue that how the changes of the traffic distribution and EON topology affect it. As the lightpath routing plays a critical role in the overall performance of the RSA, this dissertation provides a thoroughly theoretical analysis on the impacts of the aforementioned two key factors. To this end, we propose two theoretical chains, and derive the optimal routing scheme taking into account two key factors. We then treat the second subproblem of RSA, namely spectrum assignment. Any two lightpaths sharing common fiber links might have to be isolated in the spectrum domain with a proper guard-band to prevent crosstalk and/or reduce physical-layer security threats. We consider the scenario with diverse guard-band sizes, and investigate how to assign the spectrum resources efficiently in such a situation. We provide the upper and lower bounds for the optimal solution of the DSA, and further devise an efficient algorithm which can guarantee approximation ratios in some graph classes.The topology heterogeneity of Virtual Network Requests (VNRs) is one important factor hampering the performance of the VNE. However, in many specialized applications, the VNRs are of some common structural features e.g., paths and cycles. To achieve better outcomes, it is thus critical to design dedicated algorithms for these applications by accounting for topology characteristics. We prove the NP-Harness of path and cycle embeddings. To solve them, we propose some efficient algorithms and analyze their approximation ratios
19
Entesar, Abdullah Ali. "Statistical analysis of truck loading on Swedish highways." Thesis, KTH, Transportvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-45980.
Повний текст джерелаАнотація:
Vehicle over loading, or single axle over loading, is one of the major causes of pavement deterioration. Trafik Verket (TV), the Swedish Transport Administration, recognized that the current process for estimating traffic volume should be reevaluated, and if possible improved. This degree project uses data from the Bridge Weigh in Motion (BWIM) system to study the actual loads applied to Swedish highways. The axle load spectrum is plotted with the conventional frequency distribution plots, and with a new cumulative distribution approach. The paper introduces the maximum allowable potential vehicle weight MAPVW concept, and uses this visual technique to identify overloads for different vehicle geometries. The paper concludes that for 5 and 6 axle trucks the triple axle is frequently overloaded, while for longer trucks one of the dual axles is often over loaded. The highest over loads tend to be on the driving axle, suggesting incorrect loading procedures.
20
JINNO, Masahiko, Akira HIRANO, Yoshiaki SONE, Ken-ichi SATO, Hiroshi HASEGAWA, and Tatsumi TAKAGI. "Impact of Elastic Optical Paths That Adopt Distance Adaptive Modulation to Create Efficient Networks." 電子情報通信学会, 2012. https://search.ieice.org/.
Повний текст джерела
21
Ménéxiadis, Géraldine. "Détection à grande distance et localisation du supersonique "Concorde" à partir de signaux infrasonores." Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2008. http://tel.archives-ouvertes.fr/tel-00487912.
Повний текст джерелаАнотація:
L'objet de cette étude est la résolution d'un problème inverse inédit, à savoir la localisation d'un avion supersonique à partir de signaux acoustiques enregistrés par une station de mesure unique. La distance de l'aéronef à la station de mesure est a priori inconnue, mais peut varier de quelques dizaines à quelques centaines de kilomètres ou davantage. Les signaux exploités à l'occasion de ce travail se situent généralement dans la gamme infrasonore, au-dessous de 20 Hz voire de 10 Hz. L'ONERA ayant mené des campagnes de mesure en Bretagne lors des premiers vols commerciaux transatlantiques de l'avion Concorde, les premières exploitations ont consisté à reprendre les données de ces campagnes et à développer à cette occasion un code de propagation acoustique basé sur la théorie des rayons. Le code de l'ONERA existant SIMOUN a été adapté en trois dimensions pour pouvoir tenir compte de la météorologie réelle et a reçu un certain nombre d'aménagements, dont le calcul de l'atténuation acoustique en fonction de la fréquence et la prise en compte de la rotondité de la Terre dont la négligence aurait entraîné des erreurs importantes aux grandes distances. Le calcul de niveau acoustique étant peu significatif aux distances considérées, des méthodes inédites basées sur l'analyse spectrale ont été développées. Associées à une technique de goniométrie basée notamment sur le calcul des fonctions d'intercorrélation temporelles, elles nous permettent de localiser l'avion supersonique en gisement-distance. Une première méthode, valable jusqu'à 200 kilomètres environ, est basée sur la divergence en fonction de la distance à l'aéronef de l'onde de pression en N correspondant au bang sonique. Il en résulte une modification du spectre en arche caractéristique de cette onde qui peut être corrélée avec la distance de propagation sous réserve de connaître l'onde en N initialement émise, reliée à la vitesse et à la géométrie de l'avion. Une seconde méthode beaucoup plus générale consiste à évaluer l'augmentation de la pente du spectre de l'onde en N, sachant que l'absorption atmosphérique, proportionnelle à la distance parcourue, augmente avec la fréquence et que la dissipation des effets non-linéaires a également tendance à augmenter la pente du spectre du signal. Cette méthode semble convenir pour des distances comprises entre 200 et 1000 km environ et présente l'avantage d'être indépendante des caractéristiques de la source sonore. Afin de pallier aux limitations de cette méthode, principalement liées au rapport signal sur bruit, l'analyse de signaux enregistrés en Suède à 3000 km de l'avion suggère d'utiliser pour les très grandes distances une méthode basée sur la durée totale du signal. Cette durée augmente en effet avec la distance, en rapport avec le phénomène classique de "rumble" qui transforme en roulement de tonnerre le signal impulsionnel émis par un coup de foudre.
22
Iyer, Balaji S. "Design of a Classifier for Bearing Health Prognostics using Time Series Data." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543922781446885.
Повний текст джерела
23
Ledoux, Audrey. "Vers des traitements morphologiques couleur et spectraux valides au sens perceptuel et physique : Méthodes et critères de sélection." Phd thesis, Université de Poitiers, 2013. http://tel.archives-ouvertes.fr/tel-00965767.
Повний текст джерелаАнотація:
L'extension de la morphologie mathématique au domaine de la couleur ou du multi/ hyperspectral en traitement et analyse d'images n'est pas élémentaire. La majorité des approches se sont focalisées sur la formulation mathématique des opérateurs sans prendre en compte le sens physique ou perceptuel de l'information couleur/spectrale. Les outils développés dans ce travail s'inscrivent dans un nouveau formalisme générique basé sur une fonction de distance. Cette construction permet d'utiliser les opérateurs morphologiques dans le domaine de la couleur ou du multi/hyperspectral en adaptant la fonction de distance. De plus, le choix de la fonction de distance rend les opérateurs valides au sens de la perception ou de la physique. Face aux nombre croissant d'approches existantes, des critères de sélection ont été développés afin de les comparer les différentes écritures de morphologie mathématique. Ces critères sont basés sur le respect des propriétés théoriques des opérateurs, sur les propriétés métrologiques et sur l'efficacité numérique. Grâce à un formalisme prenant en compte l'information perceptuelle de la couleur et intégrant une définition valide des éléments structurants non-plats, deux types d'opérateurs de plus haut niveau ont été définis. Le premier est un détecteur d'objets spatio-colorimétrique passant par la définition d'un gabarit spatial et vectoriel. Le second, est le calcul de spectres de textures vectoriels. L'extension des deux propos au spectral a été réalisé et ouvre de nouvelles questions scientifiques. \vspace{0.5em}
24
Chotard, Nicolas. "Étude de la variabilité des Supernovae de type Ia observées par la collaboration Nearby Supernova Factory." Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00660289.
Повний текст джерелаАнотація:
Vers la fin des années 1990, l'utilisation des supernovae de type Ia (SNe Ia) comme indicateurs de distance a permis de mettre en évidence l'expansion accélérée de l'univers. Depuis lors, des campagnes d'observations de grandes envergures ont permis d'augmenter de façon significative le nombre de SNe Ia observées, mais les incertitudes systématiques liées à la qualité des échantillons de SNe Ia proches restent un facteur limitant sur la précision des mesures actuelles. C'est dans le but de réduire ces incertitudes que le projet the Nearby Supernova Factory (SNfactory), à l'aide d'un instrument spectro-photométrique dédié à l'observation des SNe Ia (the Supernova Integral Field Spectrograph), a collecté depuis 2004 plus de 3000 spectres de près de 200 SNe Ia proches. Une des limitations actuelles de leur utilisation, outre les aspects liés aux problèmes d'inter-calibration entre les différentes expériences, est celle du mélange des différentes composantes de leurs variabilités lors de la standardisation empirique de leur module de distance. Une meilleure séparation de ces composantes, ainsi que la découverte de nouveaux indicateurs de distance, font partie des améliorations que peut apporter un échantillon spectral de SNe Ia proches tel que celui de la collaboration SNfactory. Cette thèse de doctorat, effectuée à l'Institut de Physique Nucléaire de Lyon et au Lawrence Berkeley National Laboratory, s'inscrit directement dans cette problématique, en se concentrant sur la mesure d'indicateurs spectraux sur l'échantillon spectral de la collaboration Snfactory. Le plan de cette thèse est le suivant : La première partie présente le contexte scientifique ainsi que l'échantillon de SNe Ia de la collaboration SNfactory utilisé dans les analyses. La deuxième partie se concentre sur la méthode de mesure d'indicateurs spectraux appliquée à l'échantillon spectrale présenté, ainsi que sur une étude de leur sensibilité à l'extinction par le milieu interstellaire. La troisième partie est une étude des corrélations des indicateurs spectraux et de leur utilisation pour la standardisation des Sne Ia. Dans la dernière partie, une utilisation de ces indicateurs spectraux pour la détermination d'une loi d'extinction moyenne est présentée
25
Balestra, I., A. Mercurio, B. Sartoris, M. Girardi, C. Grillo, M. Nonino, P. Rosati, et al. "CLASH-VLT: DISSECTING THE FRONTIER FIELDS GALAXY CLUSTER MACS J0416.1-2403 WITH ∼800 SPECTRA OF MEMBER GALAXIES." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/621406.
Повний текст джерелаАнотація:
We present VIMOS-Very Large Telescope (VLT) spectroscopy of the Frontier Fields cluster MACS. J0416.1-2403 (z = 0.397). Taken as part of the CLASH-VLT survey, the large spectroscopic campaign provided more than 4000 reliable redshifts over similar to 600 arcmin(2), including similar to 800 cluster member galaxies. The unprecedented sample of cluster members at this redshift allows us to perform a highly detailed dynamical and structural analysis of the cluster out to similar to 2.2 r(200) (similar to 4Mpc). Our analysis of substructures reveals a complex system composed of a main massive cluster (M-200 similar to 0.9 x 10(15) M-circle dot and sigma(V r200) similar to 1000 km s(-1)) presenting two major features: (i) a bimodal velocity distribution, showing two central peaks separated by Delta V-rf similar to 1100 km s(-1) with comparable galaxy content and velocity dispersion, and (ii) a projected elongation of the main substructures along the NE-SW direction, with a prominent sub-clump similar to 600 kpc SW of the center and an isolated BCG approximately halfway between the center and the SW clump. We also detect a low-mass structure at z similar to 0.390, similar to 10' south of the cluster center, projected at similar to 3Mpc, with a relative line-of-sight velocity of Delta V-rf similar to 1700 km s(-1). The cluster mass profile that we obtain through our dynamical analysis deviates significantly from the "universal" NFW, being best fit by a Softened Isothermal Sphere model instead. The mass profile measured from the galaxy dynamics is found to be in relatively good agreement with those obtained from strong and weak lensing, as well as with that from the X-rays, despite the clearly unrelaxed nature of the cluster. Our results reveal an overall complex dynamical state of this massive cluster and support the hypothesis that the two main subclusters are being observed in a pre-collisional phase, in agreement with recent findings from radio and deep X-ray data. In this article, we also release the entire redshift catalog of 4386 sources in the field of this cluster, which includes 60 identified Chandra X-ray sources and 105 JVLA radio sources.
26
Papadimitriou, Panayiotis D. "Code design based on metric-spectrum and applications." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1365.
Повний текст джерелаАнотація:
We introduced nested search methods to design (n, k) block codes for arbitrary channels by optimizing an appropriate metric spectrum in each iteration. For a given k, the methods start with a good high rate code, say k/(k + 1), and successively design lower rate codes up to rate k/2^k corresponding to a Hadamard code. Using a full search for small binary codes we found that optimal or near-optimal codes of increasing length can be obtained in a nested manner by utilizing Hadamard matrix columns. The codes can be linear if the Hadamard matrix is linear and non-linear otherwise. The design methodology was extended to the generic complex codes by utilizing columns of newly derived or existing unitary codes. The inherent nested nature of the codes make them ideal for progressive transmission.
Extensive comparisons to metric bounds and to previously designed codes show the optimality or near-optimality of the new codes, designed for the fading and the additive white Gaussian noise channel (AWGN). It was also shown that linear codes can be optimal or at least meeting the metric bounds; one example is the systematic pilot-based code of rate k/(k + 1) which was proved to meet the lower bound on the maximum cross-correlation. Further, the method was generalized such that good codes for arbitrary channels can be designed given the corresponding metric or the pairwise error probability.
In synchronous multiple-access schemes it is common to use unitary block codes to transmit the multiple users information, especially in the downlink. In this work we suggest the use of newly designed non-unitary block codes, resulting in increased throughput efficiency, while the performance is shown not to be substantially sacrificed. The non-unitary codes are again developed through suitable nested searches. In addition, new multiple-access codes are introduced that optimize certain criteria, such as the sum-rate capacity.
Finally, the introduction of the asymptotically optimum convolutional codes for a given constraint length, reduces dramatically the search size for good convolutional codes of a certain asymptotic performance, and the consequences to coded code-division multiple access (CDMA) system design are highlighted.
27
Nader, Rafic. "A study concerning the positive semi-definite property for similarity matrices and for doubly stochastic matrices with some applications." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMC210.
Повний текст джерелаАнотація:
La théorie des matrices s'est développée rapidement au cours des dernières décennies en raison de son large éventail d'applications et de ses nombreux liens avec différents domaines des mathématiques, de l'économie, de l'apprentissage automatique et du traitement du signal. Cette thèse concerne trois axes principaux liés à deux objets d'étude fondamentaux de la théorie des matrices et apparaissant naturellement dans de nombreuses applications, à savoir les matrices semi-définies positives et les matrices doublement stochastiques.Un concept qui découle naturellement du domaine de l'apprentissage automatique et qui est lié à la propriété semi-définie positive est celui des matrices de similarité. En fait, les matrices de similarité qui sont semi-définies positives revêtent une importance particulière en raison de leur capacité à définir des distances métriques. Cette thèse explorera la propriété semi-définie positive pour une liste de matrices de similarité trouvées dans la littérature. De plus, nous présentons de nouveaux résultats concernant les propriétés définie positive et semi-définie trois-positive de certains matrices de similarité. Une discussion détaillée des nombreuses applications de tous ces propriétés dans divers domaines est également établie.D'autre part, un problème récent de l'analyse matricielle implique l'étude des racines des matrices stochastiques, ce qui s'avère important dans les modèles de chaîne de Markov en finance. Nous étendons l'analyse de ce problème aux matrices doublement stochastiques semi-définies positives. Nous montrons d'abord certaines propriétés géométriques de l'ensemble de toutes les matrices semi-définies positives doublement stochastiques d'ordre n ayant la p-ième racine doublement stochastique pour un entier donné p . En utilisant la théorie des M-matrices et le problème inverse des valeurs propres des matrices symétriques doublement stochastiques (SDIEP), nous présentons également quelques méthodes pour trouver des classes de matrices semi-définies positives doublement stochastiques ayant des p-ièmes racines doublement stochastiques pour tout entier p.Dans le contexte du SDIEP, qui est le problème de caractériser ces listes de nombres réels qui puissent constituer le spectre d’une matrice symétrique doublement stochastique, nous présentons quelques nouveaux résultats le long de cette ligne. En particulier, nous proposons d’utiliser une méthode récursive de construction de matrices doublement stochastiques afin d'obtenir de nouvelles conditions suffisantes indépendantes pour SDIEP. Enfin, nous concentrons notre attention sur les spectres normalisés de Suleimanova, qui constituent un cas particulier des spectres introduits par Suleimanova. En particulier, nous prouvons que de tels spectres ne sont pas toujours réalisables et nous construisons trois familles de conditions suffisantes qui affinent les conditions suffisantes précédemment connues pour SDIEP dans le cas particulier des spectres normalisés de SuleimanovaMatrix theory has shown its importance by its wide range of applications in different fields such as statistics, machine learning, economics and signal processing. This thesis concerns three main axis related to two fundamental objects of study in matrix theory and that arise naturally in many applications, that are positive semi-definite matrices and doubly stochastic matrices.One concept which stems naturally from machine learning area and is related to the positive semi-definite property, is the one of similarity matrices. In fact, similarity matrices that are positive semi-definite are of particular importance because of their ability to define metric distances. This thesis will explore the latter desirable structure for a list of similarity matrices found in the literature. Moreover, we present new results concerning the strictly positive definite and the three positive semi-definite properties of particular similarity matrices. A detailed discussion of the many applications of all these properties in various fields is also established.On the other hand, an interesting research field in matrix analysis involves the study of roots of stochastic matrices which is important in Markov chain models in finance and healthcare. We extend the analysis of this problem to positive semi-definite doubly stochastic matrices.Our contributions include some geometrical properties of the set of all positive semi-definite doubly stochastic matrices of order n with nonnegative pth roots for a given integer p. We also present methods for finding classes of positive semi-definite doubly stochastic matrices that have doubly stochastic pth roots for all p, by making use of the theory of M-Matrices and the symmetric doubly stochastic inverse eigenvalue problem (SDIEP), which is also of independent interest.In the context of the SDIEP, which is the problem of characterising those lists of real numbers which are realisable as the spectrum of some symmetric doubly stochastic matrix, we present some new results along this line. In particular, we propose to use a recursive method on constructing doubly stochastic matrices from smaller size matrices with known spectra to obtain new independent sufficient conditions for SDIEP. Finally, we focus our attention on the realizability by a symmetric doubly stochastic matrix of normalised Suleimanova spectra which is a normalized variant of the spectra introduced by Suleimanova. In particular, we prove that such spectra is not always realizable for odd orders and we construct three families of sufficient conditions that make a refinement for previously known sufficient conditions for SDIEP in the particular case of normalized Suleimanova spectra
28
Bittencourt, Thiago de Morais Gonçalves. "Pré-processamento digital de imagens obtidas na faixa espectral do infravermelho distante." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18152/tde-23102012-090741/.
Повний текст джерелаАнотація:
Este trabalho apresenta a pesquisa e desenvolvimento de algoritmos de pré-processamento digital de imagens para câmeras térmicas não refrigeradas na faixa espectral do infravermelho distante. O estudo de câmeras infravermelhas é uma questão estratégica, uma vez que tem aplicações militares, civis e científicas. Este trabalho define a concepção e implementação de algoritmos de pré-processamento de imagem necessários para obter imagens com baixo ruído e alto contraste, tais como: correção de não-uniformidade, substituição de pixels defeituosos, geração de histograma, aumento de contraste e processamento de saída do pixel, com taxa de 30 quadros por segundo, utilizando detector não-resfriado com matriz de plano focal de 320 x 240 pixels. Neste trabalho todos os algoritmos foram implementados em software para se obter resultados rapidamente e, assim, facilitar a validação dos códigos. Foram gerados resultados de caracterização eletro-óptica do sistema montado com indicação das principais figuras de mérito que norteiam o estudo desta tecnologia, tais como: componentes de ruído tridimensionais, potência equivalente de ruído, responsividade e relação sinal-ruído. Os resultados indicam que os algoritmos de pré-processamento de imagem propostos aumentam a qualidade da imagem a ser exibida, e os resultados das figuras de mérito calculadas sobre o vídeo digital mostram que todas as métricas apresentaram resultados satisfatórios.This work aims to present the research and development of digital image processing algorithms for uncooled LWIR thermal camera in Brazil. The study of an infrared thermal camera is a strategic issue since that has more and more applications in military, judicature, rescue, industry, hospital and science areas. This work describes the design and implementation of all image-processing algorithms required to obtain high-performance images with low noise and high contrast, such as: functions for non-uniformity correction of sensor deficiencies, dead-pixel replacement algorithms, histogram generation, contrast enhancement methods and output pixel processing with frame rate of 30 frames per second based on 320 x 240 Uncooled Focal Plane Array (UFPA). In this work all algorithms was implemented in software to get results quickly and to facilitate the validation of computer codes. There are some results of electro-optical characterization on the assembled system, indicating the main figures of merit that guide the study of this technology, such as: 3D noise components, noise equivalent power (NEP), signal transfer function (SiTF) and noise equivalent temperature difference (NETD). The results indicate that the proposed imageprocessing algorithms increase the quality of the corrected image, and the test results through the digital video of the infrared camera show that all metrics are in accordance with its nominal value.
29
Knapik, Alain. "Étude d'un échantillon d'étoiles géantes rouges carbonées et d'étoiles à baryum II : distributions spectrales d'énergie, parallaxes, températures effectives et évolution." Lyon 1, 1999. http://www.theses.fr/1999LYO10344.
Повний текст джерелаАнотація:
Une nouvelle méthode d'analyse des distributions spectrale d'énergie a été mise au point. Elle utilise une base de données photométriques d'environ 600 étoiles (carbonées ou baryum II) qui a été constituée. Cette méthode permet de classer chaque étoile dans un groupe défini et de déterminer l'extinction interstellaire subie. Pour certaines étoiles (variables RCB, Miras. . . ), l'extinction circumstellaire est évaluée, plaçant des contraintes sur les propriétés optiques et la distribution spatiale des poussières responsables. L'analyse des données astrométriques HIPPARCOS pour environ 400 étoiles de la base de données a permis d'évaluer les biais statstiques affectant les parallaxes et d'évaluer la distribution spatiale (disque plat) des carbonées du voisinage solaire. Une densité spatiale de 40 à 70 étoiles par kpc a été obtenue. Une étude détaillée des températures effectives et des flux intégrés a conduit à une échelle uniforme de températures sur le domaine 1800-5600 K, bien corélée avec nos groupes. Des corrections bolométriques ont été calibrées. Le diagramme HR a été construit puis confronté aux prédictions des modèle d'évolution. La valeur médiane des masses s'établit à 2M. Le modèle TP AGB semble convenir, mais le cas des étoiles carbonées peu brillantes reste mystérieux. Les étoiles à BaII peuplent toutes les classes de luminosité (Ib à V) : elles ont acquis leurs particularités par échange de matière dans un système double. La fonction de luminosité obtenue a été comparée à celle des carbonnées des Nuages de Magellan et la distribution spatiale des étoiles carbonées affinée. Une relation période-luminosité a été établie qui donne 18,5 ± 0,17 pour le module de distance du Grand Nuage de Magellan
30
Taylor, Susanne Elizabeth. "Australian parent perspective of schooling choices and relationships for their child on the autism spectrum." Thesis, Griffith University, 2017. http://hdl.handle.net/10072/377619.
Повний текст джерелаАнотація:
Children with an autism diagnosis often struggle in a mainstream school environment and yet this is where increasing numbers of them are receiving their education (Roberts & Simpson, 2016). Children with autism more often struggle with social isolation and rejection, behaviour difficulties, bullying and problems with comprehension and transitioning within the classroom environment (Majoko, 2016a). These difficulties impact negatively on the educational outcomes for this group of students (Keen, Webster & Ridley, 2016).
Parents of children on the spectrum are aware from the time their child is very young that they will experience school differently from their peers without a diagnosis, and often feel powerless in their role as advocate for their child in a school context (McDonald, 2014). Parent voices need to be heard and considered if educational outcomes for these children are to improve.
The Longitudinal Study of Australian Students with Autism (LASA) is an attempt to address this situation. This eight-year government funded study has recruited parents of children in two cohort groups to provide both personal data and approve the collection of school data about their children for the study. A small but significant number of parents have declined permission for the researchers to contact their child’s school. The reasons for this decision and the school/home communication challenges represented by this decision are the focus of this project.
An explanatory sequential mixed methods design was used to compare the attitudes of three groups of parents identified from existing data: parents who educate at home, parents enrolled in schools of distance education and a control group of parents whose children attend mainstream schools. Each family received a link to an online survey requesting information about their relationship with staff at their child’s current school setting (including teachers overseeing a distance education program) or a past setting if that is more relevant. Further in-depth lived experience data were then collected through interviews with a small number of parents from each group.
Understanding more about parental lived experience in relation to their child’s schooling in different parts of Australia will better inform policy decisions about practical implications of including students with autism in mainstream schools.Thesis (Masters)
Master of Education and Professional Studies Research (MEdProfStRes)
School Educ & Professional St
Arts, Education and Law
Full Text
31
Chen, Changlin. "The performance analysis and decoding of high dimensional trellis-coded modulation for spread spectrum communications." Ohio : Ohio University, 1997. http://www.ohiolink.edu/etd/view.cgi?ohiou1174616331.
Повний текст джерела
32
Angeletti, Mélodie. "Traitement de données multi-spectrales par calcul intensif et applications chez l'homme en imagerie par résonnance magnétique nucléaire." Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC004/document.
Повний текст джерелаАнотація:
L'imagerie par résonance magnétique fonctionnelle (IRMf) étant une technique non invasive pour l'étude de cerveau, elle a été employée pour comprendre les mécanismes cérébraux sous-jacents à la prise alimentaire. Cependant, l'utilisation de stimuli liquides pour simuler la prise alimentaire engendre des difficultés supplémentaires par rapport aux stimulations visuellement habituellement mises en œuvre en IRMf. L'objectif de cette thèse a donc été de proposer une méthode robuste d'analyse des données tenant compte de la spécificité d'une stimulation alimentaire. Pour prendre en compte le mouvement dû à la déglutition, nous proposons une méthode de censure fondée uniquement sur le signal mesuré. Nous avons de plus perfectionné l'étape de normalisation des données afin de réduire la perte de signal. La principale contribution de cette thèse est d'implémenter l'algorithme de Ward de sorte que parcelliser l'ensemble du cerveau soit réalisable en quelques heures et sans avoir à réduire les données au préalable. Comme le calcul de la distance euclidienne entre toutes les paires de signaux des voxels représente une part importante de l'algorithme de Ward, nous proposons un algorithme cache-aware du calcul de la distance ainsi que trois parallélisations sur les architectures suivantes : architecture à mémoire partagée, architecture à mémoire distribuée et GPU NVIDIA. Une fois l'algorithme de Ward exécuté, il est possible d'explorer toutes les échelles de parcellisation. Nous considérons plusieurs critères pour évaluer la qualité de la parcellisation à une échelle donnée. À une échelle donnée, nous proposons soit de calculer des cartes de connectivités entre les parcelles, soit d'identifier les parcelles répondant à la stimulation à l'aide du coefficient de corrélation de PearsonAs a non-invasive technology for studying brain imaging, functional magnetic resonance imaging (fMRI) has been employed to understand the brain underlying mechanisms of food intake. Using liquid stimuli to fake food intake adds difficulties which are not present in fMRI studies with visual stimuli. This PhD thesis aims to propose a robust method to analyse food stimulated fMRI data. To correct the data from swallowing movements, we have proposed to censure the data uniquely from the measured signal. We have also improved the normalization step of data between subjects to reduce signal loss.The main contribution of this thesis is the implementation of Ward's algorithm without data reduction. Thus, clustering the whole brain in several hours is now feasible. Because Euclidean distance computation is the main part of Ward algorithm, we have developed a cache-aware algorithm to compute the distance between each pair of voxels. Then, we have parallelized this algorithm for three architectures: shared-memory architecture, distributed memory architecture and NVIDIA GPGPU. Once Ward's algorithm has been applied, it is possible to explore multi-scale clustering of data. Several criteria are considered in order to evaluate the quality of clusters. For a given number of clusters, we have proposed to compute connectivity maps between clusters or to compute Pearson correlation coefficient to identify brain regions activated by the stimulation
33
Shaikh, Shaunak Mehboob. "Light Harvesting and Energy Transfer in Metal-Organic Frameworks." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/104022.
Повний текст джерелаАнотація:
A key component of natural photosynthesis are the antenna chromophores (chlorophylls and carotenoids) that capture solar energy and direct it towards the reaction centers of photosystems I and II. Highlighted by highly-ordered crystal structures and synthetic tunability via crystal engineering, metal–organic frameworks (MOFs) have the potential to mimic the natural photosynthetic systems in terms of the efficiency and directionality of energy transfer. Owing to their larger surface areas, MOFs have large absorption cross sections, which amplifies the rate of photon collection. Furthermore, MOFs can be constructed using analogues of chlorophyll and carotenoids that can participate in long-range energy transfer. Herein, we aimed to design photoactive MOFs that can execute one of the critical steps involved in photosynthesis - photon collection and subsequent energy transfer.
The influence of spatial arrangement of chromophores on the efficiency and directionality of excitation energy transfer (EET) was investigated in a series of mixed-ligand pyrene- and porphyrin-based MOFs. Due to the significant overlap between the emission spectrum of 1,3,6,8-tetrakis(p-benzoic acid)pyrene (TBAPy) and the absorption spectrum of meso-tetrakis(4-carboxyphenyl)porphyrin (TCPP), the co-assembly of these two ligands in a MOF should enable facile energy transfer. Bearing this in mind, three TBAPy-based MOFs with markedly different network topologies (ROD-7, NU-901, and NU-1000) were chosen and a small number of TCPP units were incorporated in their backbone. To gain insight into the photophysical properties of mixed-ligand MOFs, we conducted time-resolved and steady-state fluorescence measurements on them. Stern-Volmer analysis was performed on the fluorescence lifetime data of mixed-ligand MOFs to determine the quenching constants. The quenching constant values for ROD-7, NU-901, NU-1000, and TBAPy solution were found to be 15.03 ± 0.82 M-1, 10.25 ± 0.99 M-1, 8.16 ± 0.41 M-1, and 3.35 ± 0.30 respectively. In addition, the ratio of the fluorescence intensities of TCPP and TBAPy was used to calculate the EET efficiencies in each of the three MOFs. EET efficiencies were in the following order: ROD-7 > NU-901 > NU-1000 > TBAPy-solution. Based on the trends observed for quenching constants and EET efficiencies, two conclusions were drawn: (1) the ligand-to-ligand energy transfer mechanism in MOFs outperforms the diffusion-controlled mechanism in solution phase, (2) energy transfer in MOFs is influenced by their structural parameters and spectral overlap integrals. The enhanced EET efficiency in ROD-7 is attributed to shorter interchromophoric distance, larger orientation factor, and larger spectral overlap integral. Directionality of energy transfer in these MOFs was assessed by calculating excitonic couplings between neighboring TBAPy linkers using the atomic transition charges approach. Rate constants of EET (kEET) along different directions were determined from the excitonic couplings. Based on the kEET values, ROD-7 is expected to demonstrate highly anisotropic EET along the stacking direction.
In order to explore the mechanistic aspects of EET in porphyrin-based MOFs, we studied the energy transfer characteristics of PCN-223, a zirconium-based MOF containing TCPP ligands. After performing structural characterization, the photophysical properties of PCN-223 and free TCPP were investigated using steady state and time-resolved spectroscopy. pH-dependent fluorescence quenching experiments were performed on both the MOF and ligand. Stern-Volmer analysis of quenching data revealed that the quenching rate constants for PCN-223 and TCPP were 8.06 ± 1011 M-1s-1 and 2.71 ± 1010 M-1s-1 respectively. The quenching rate constant for PCN-223 is, therefore, an order of magnitude larger than that for TCPP. Additionally, PCN-223 demonstrated a substantially higher extent of quenching (q = 93%) as compared to free TCPP solution (q = 51%), at similar concentrations of quencher. The higher extent of quenching in MOF is attributed to energy transfer from neutral TCPP linkers to N-protonated TCPP linkers. Using the Förster energy transfer model, the rate constant of EET in PCN-223 was calculated. The magnitude of rate constant was in good agreement with the kEET values reported for other porphyrin-based MOFs. Nanosecond transient absorption measurements on PCN-223 revealed the presence of a long-lived triplet state (extending beyond 200 μs) that exhibits the characteristic features of a TCPP-based triplet state. The lifetime of MOF is shorter than that of free ligand, which may be attributed to triplet-triplet energy transfer in the MOF. Lastly, femtosecond transient absorption spectroscopy was employed to study the ultrafast photophysical processes taking place in TCPP and PCN-223. Kinetic analysis of the femtosecond transient absorption data of TCPP and PCN-223 showed the presence of three distinct time components that correspond to: (a) solvent-induced vibrational reorganization of excitation energy, (b) vibrational cooling, and (c) fluorescence.
Materials that allow control over the directionality of energy transfer are highly desirable. Core-shell nanocomposites have recently emerged as promising candidates for achieving long-distance, directional energy transfer. For our project, we aim to employ UiO-67-on-PCN‐222 composites as model systems to explore the possibility of achieving directional energy transfer in MOF-based core-shell structures. The core–shell composites were synthesized by following a previously published procedure. Appropriate amounts of Ruthenium(II) tris(5,5′-dicarboxy-2,2′-bipyridine), RuDCBPY, were doped in the shell layer to produce a series of Ru-UiO-67-on-PCN‐222 composites with varying RuDCBPY loadings (CS-1, CS-2, and CS-3). The RuDCBPY-doped core–shell composites were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) imaging, Nitrogen adsorption-desorption isotherms, and diffuse reflectance spectroscopy. Efforts are currently underway to quantify RuDCBPY loadings in CS-1, CS-2, and CS-3. After completing structural characterization, the photophysical properties of CS-1, CS-2, and CS-3 will be investigated with the help of time-resolved and steady-state fluorescence spectroscopy.Doctor of Philosophy
The pigment−protein complexes in natural photosynthetic units (also known as light harvesting antennas) efficiently capture solar energy and transfer this energy to reaction centers that carry out water splitting reactions. The collective chromophoric behavior of antennas can be replicated by metal-organic frameworks (MOFs). MOFs are crystalline, self-assembled materials composed of metal clusters connected by organic molecules. In this dissertation, we study the factors that govern the energy transfer and light harvesting capabilities of MOFs. In chapter 2, we examined the role of 3D structure of MOFs in energy transfer. In chapter 3, we investigated the influence of pH and temperature on the photophysical properties of MOFs. In chapter 4, we explored the possibility of energy transfer in novel MOF-on-MOF composites. This work is intended to pave the way for the construction of highly efficient MOF-based materials that can serve as the light harvesting and energy-transfer components in solar energy conversion devices.
34
Ben, Jamaa-Joussemet Salma. "Codage-décodage source-canal conjoint des codes arithmétiques : application au décodage robuste des vidéos codées H.264." Paris 11, 2006. http://www.theses.fr/2006PA112331.
Повний текст джерелаАнотація:
Cette thèse s'inscrit dans le contexte du codage/décodage source-canal conjoint (CSCC/DSCC) des codes arithmétiques (CA). Nous nous intéressons au décodage robuste des trames codées par CABAC, une version du CA adoptée dans des standards tels que le H. 264. Nous proposons un estimateur au sens du maximum a posteriori, sans approximations, prenant compte les contraintes d'une implémentation réaliste du CA. Pour l'évaluation de cet estimateur, nous utilisons les techniques de décodage séquentiel, qui posent, en revanche, des problèmes de complexité. Nous développons alors un critère objectif de décision permettant d'ajuster le compromis complexité-efficacité. Ensuite, nous nous intéressons à la caractérisation analytique de la robustesse des schémas de CSCC utilisant le CA. Dans ce but, nous représentons le CA par une machine à états finis pour générer un treillis bi-dimensionnel adapté à un décodage Viterbi. Ce treillis permet de calculer la distance libre et le spectre des distances du CA. Les outils analytiques développés sont exploitées pour concevoir un schéma de CSCC optimisé de manière à minimiser asymptotiquement la probabilité d'erreur symboleThis thesis deals with joint source-channel coding and decoding (JSCC/JSCD) schemes involving arithmetic codes (AC). First, we develop a JSCD technique based on MAP estimation of CABAC encoded data. This estimator is considered to be exact as it is evaluated without approximations and with respect of the constraints imposed by an actual implementation of AC. The evaluation of the proposed MAP estimator is achieved using an improved sequential decoding technique, allowing to adjust the decoder complexity-efficiency trade-off. The purpose of the second part of this thesis is to provide analytical tools to predict and evaluate the effectiveness of the redundancy introduced by the JSCC schemes into AC. Integer binary AC is then modelled by a reduced-state automaton to obtain a bit-clock trellis. Distance spectra are then derived. The obtained distance properties provide an objective criteria that are then exploited to design efficient error-correcting arithmetic codes
35
Body, Monique. "Détermination et modélisation des paramètres de résonance magnétique nucléaire de (19)F et (27)Al dans les fluoroaluminates : relation avec la structure à courte et moyenne distance." Le Mans, 2005. http://cyberdoc.univ-lemans.fr/theses/2005/2005LEMA1008.pdf.
Повний текст джерелаАнотація:
Cette thèse comporte deux volets. Le premier, expérimental, a consisté en la synthèse d'une série de fluoroaluminates cristallisés et vitreux (binaires CaF2-AlF3 et BaF2-AlF3 et ternaire BaF2- CaF2-AlF3) sous forme de poudre et en leur étude par Résonance Magnétique Nucléaire du Solide haute résolution des noyaux 19F et 27Al. Les expériences RMN les plus récentes (MAS, SATRAS, MQ-MAS) ont été mises en œuvre. Elles ont permis l'obtention de spectres correspondant à environ quatre-vingts sites d'ions fluorure F- et une quinzaine de sites d'ions aluminium Al3+ pour les fluoroaluminates cristallisés. Les paramètres spectroscopiques pertinents (déplacements chimiques isotropes pour 19F et 27Al, paramètres d'interaction quadripolaire pour 27Al) ont été déterminés par reconstruction des spectres des échantillons cristallisés et vitreux. Le second volet du travail a porté sur la modélisation de ces paramètres : 1/ déplacement chimique isotrope de 19F par une méthode semi-empirique (" modèle de superposition " développé au Mans) dans les fluoroaluminates cristallisés et des calculs ab-initio (code GAUSSIAN) sur un très grand nombre de fluorures inorganiques cristallisés; 2/ paramètres quadripolaires de 27Al par des calculs ab-initio (code WIEN2k) dans des fluoroaluminates cristallisés. La comparaison entre les paramètres calculés et expérimentaux est en général tout à fait satisfaisante et permet de discuter les valeurs des paramètres RMN en terme de liaison chimique, de connectivité des entités constituant le réseau et d'ordre à courte et moyenne distances. Elle permet en outre de caractériser le réseau des fluoroaluminates vitreuxThis work is divided into two parts. The first one, experimental, is related to the synthesis of crystallized and glassy fluoroaluminates (CaF2-AlF3 and BaF2-AlF3 binaries, and BaF2-CaF2-AlF3 ternary) as powder samples, and their study using 19F and 27Al high resolution solid state Nuclear Magnetic Resonance. The most recent NMR experiments (MAS, SATRAS, MQ-MAS) have been worked out. Experimental spectra have been recorded for about eighty sites of F- fluorine ion and fifteen sites of Al3+ aluminium ion in the crystallized fluoroaluminates. The relevant spectroscopic parameters (isotropic chemical shift for 19F and 27Al, quadrupolar parameters for 27Al) have been determined by reconstruction of the crystallized and glassy samples spectra. The second part of this work is devoted to the modeling of these NMR parameters: 1/ 19F isotropic chemical shift using a semi-empirical method (“superposition model” developed in Le Mans) in the crystallized fluoroaluminates and using ab initio calculations (GAUSSIAN code) on a large number of crystallized inorganic fluorides; 2/ 27Al quadrupolar parameters using ab initio calculations (WIEN2k code) in crystallized fluoroaluminates. The comparison between the calculated and experimental parameters was generally satisfactory and allows us to discuss the NMR parameter values in term of chemical bond, connectivity of the network entities, and short and mean range order. Moreover, the network of fluoroaluminate glasses was also characterized
36
Léget, Pierre-François. "Modélisation des spectres des Supernovas de Type Ia observés par la collaboration The Nearby Supernova Factory dans le but d’améliorer les mesures de distances extragalactiques." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22730/document.
Повний текст джерелаАнотація:
À la fin des années 90, deux équipes indépendantes ont montré l’expansion accélérée de notre Univers, à partir des mesures de distances de supernovas de type Ia (SNIa). Depuis, une des priorités de la cosmologie moderne est de caractériser ce phénomène et d’en comprendre ses fondements. L’amélioration des mesures de distance réalisées à partir des SNIa est une technique majeure permettant de mieux caractériser l’accélération et donc de déterminer la nature physique de ce phénomène. Ce document développe un nouveau modèle de distribution spectrale en énergie de SNIa nommé le Supernova Useful Generator And Reconstructor (SUGAR) permettant d’améliorer les mesures des distances. Ce modèle est construit à partir des propriétés spectrales des SNIa et des données spectrophotométriques de la collaboration The Nearby Supernova Factory. L’avancée principale, proposée dans SUGAR, réside dans l’ajout de deux paramètres supplémentaires pour caractériser la variabilité des SNIa. Le premier dépend des propriétés des vitesses des éjectas des SNIa, le deuxième dépend de leurs raies du calcium. L’ajout de ces paramètres, ainsi que la grande qualité des données de la collaboration the Nearby Supernova Factory font de SUGAR le meilleur modèle qui existe pour décrire la distribution spectrale en énergie des SNIa et améliore les mesures des distances de l’ordre de 15% par rapport à la méthode usuelle. Les performances de ce modèle en font un excellent candidat pour préparer les expériences futures comme LSST ou WFIRST. Par ailleurs, ce document présente une analyse sur l’effet de l’appartenance d’une SNIa à un amas de galaxies sur sa mesure de distance. Les galaxies d’un amas possèdent une vitesse propre largement supérieure à la valeur supposée lors de la mesure des distances avec les SNIa. Ceci a pour conséquence d’introduire une source d’erreur systématique sur la mesure de distance. Le fait de ne pas prendre en compte cet effet peut dégrader la mesure de distance de l’ordre de 2,5% pour les SNIa appartenant à un amas. Cette analyse à été réalisée en utilisant les données de la collaboration the Nearby Supernova Factory et des catalogues public d’amas de galaxiesAt the end of the 90s, two independent teams showed, based on distance measurements of type Ia supernovæ (SNIa), that expansion of our Universe is accelerating. Since then, one of the priorities of modern cosmology is to characterize this phenomenon and to understand its nature. The improvement of distance measurements of SNIa is one technique to improve the constraints on acceleration and to determine the physical nature of it. This document develops a new SNIa spectral energy distribution model, called the Supernova Useful Generator and Reconstructor (SUGAR), which improves distance measurement. This model is constructed from SNIa spectral properties and spectrophotometric data from The Nearby Supernova Factory collaboration. The main advancement proposed in SUGAR is the addition of two additional parameters to characterize the SNIa variability. The first depends on the properties of SNIa ejecta velocity, the second depends on their calcium lines. The addition of these parameters as well as the high quality of the data of The Nearby Supernova Factory collaboration make SUGAR the best model available to describe the spectral energy distribution of SNIa and improves distances measurements of the order of 15 % relative to the usual method. The performance of this model makes it an excellent candidate for preparing future experiments like LSST or WFIRST. In addition, this document presents an analysis of the effect of SNIa belonging to a galaxy cluster on its distance measurement. Galaxies of a cluster have a peculiar velocity much higher than the assumed value when measuring distances with SNIa. This has the effect of introducing a systematic error into the distance measurement. Failure to take into account this effect may degrade the distance measurement by 2.5% for SNIa belonging to a cluster. This analysis was carried out using data from the collaboration of the Nearby Supernova Factory and public catalogs of galaxy cluster
37
Tergiman, Yvette Suzanne. "Contribution à l'étude théorique de la dépendance en la distance internucléaire des constantes de structure diatomiques à partir des données spectroscopiques de vibration-rotation." Lyon 1, 1985. http://www.theses.fr/1985LYO10019.
Повний текст джерелаАнотація:
Analyse theorique du lien entre parametres moleculaires, deduits de l'experience, et vraies constantes structurales. Proposition d'une methode analytique pour determiner ces vraies constantes, associees aux differents termes d'interaction de l'hamiltonien, en fonction de la distance internucleaire. Determination des formes radiales des parametres de dedoublement lambda , p(r) et q(r), des etats x**(2)pi de oh,et a**(2)pi de cn, du parametre spin-rotation gamma (r) de l'etat a**(2)sigma **(+) de hcl**(+), des parametres spin-orbite de l'etat b**(3)pi ::(g) de n::(2), des parametres spin-orbite et spin-rotation des etats x**(2)pi de oh, ot, cuo et a**(2)pi de cn, yo
38
Bezek, Perit. "A Clustering Method For The Problem Of Protein Subcellular Localization." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607981/index.pdf.
Повний текст джерелаАнотація:
In this study, the focus is on predicting the subcellular localization of a protein, since subcellular localization is helpful in understanding a protein&rsquos functions. Function of a protein may be estimated from its sequence. Motifs or conserved subsequences are strong indicators of function. In a given sample set of protein sequences known to perform the same function, a certain subsequence or group of subsequences should be common
that is, occurrence (frequency) of common subsequences should be high. Our idea is to find the common subsequences through clustering and use these common groups (implicit motifs) to classify proteins. To calculate the distance between two subsequences, traditional string edit distance is modified so that only replacement is allowed and the cost of replacement is related to an amino acid substitution matrix. Based on the modified string edit distance, spectral clustering embeds the subsequences into some transformed space for which the clustering problem is expected to become easier to solve. For a given protein sequence, distribution of its subsequences over the clusters is the feature vector which is subsequently fed to a classifier. The most important aspect if this approach is the use of spectral clustering based on modified string edit distance.
39
Machado, Daniel. "Improving automated redshift detection in the low signal-to-noise regime for Large Sky Surveys." Thesis, Paris 11, 2015. http://www.theses.fr/2014PA112427.
Повний текст джерелаАнотація:
Le décalage vers le rouge est la principale mesure par laquelle les astronomes peuvent cartographier l’Univers dans la direction radiale. Afin de tester les hypothèses d’homogénéité et d’isotropie, il est nécessaire de mesurer avec precision le décalage vers le rouge d’un grand nombre de galaxies. De plus, différents modèles cosmologiques ne peuvent être distingués qu’au travers d’une analyse précise des structures à grandes échelles tracées par ces galaxies. Pour obtenir un grand nombre de ces mesures, il est nécessaire de mener d'importantes campagnes d’observations pour établir des relevés couvrant une large portion du ciel. Ces mesures trouvent aussi d’autres applications en astronomie comme par exemple l’analyse du cisaillement gravitationnel, la calibration des mesures photométriques, l’étude des halos de matière noire, de la morphologie des galaxies, des structures à grandes échelles et de la distribution des galaxies.Dans tous les relevés de galaxies, les mesures les plus problématiques sont pour les objets de plus faible luminosité, où le bruit instrumental devient gênant, et qui se trouvent être en général les objets les plus lointains. Pour ces objets, les mesures de décalages vers le rouge peuvent souvent devenir imprécise et, la plupart du temps, elles sont simplement exclues de l’analyse en appliquant des coupures en magnitudes ou en rapport signal à bruit. Cette procédure est une méthode brutale pour séparer les mesures probablement imprécises des mesures fiables.Dans cette thèse, nous développons un algorithme permettant la mesure du décalage vers le rouge des spectres de galaxies dans le regime de faible rapport signal à bruit. La première partie de cette thèse présente les différents concepts relatifs à l’estimation du décalage vers le rouge et au débruitrage de signaux par transformation en ondelettes et filtrage par taux de fausse détection (False Detection Rate, FDR en anglais). La seconde partie détaille comment ces concepts sont mis à contribution dans l’élaboration de l’algorithme Darth Fader (Denoised and Automatic Redshifts THresholded with a False DEtection Rate). Enfin, la dernière partie présente l’application de cet algorithme à des données synthétiques générées à partir du COSMOS Mock Catalogue, mais aussi sur des données réelles tirées du relevé WiggleZ.Nous montrons que Darth Fader fonctionne efficacement à bas rapport signal à bruit étant donné un choix approprié du taux de fausse détection et d’un critère de comptage de traits caractéristiques judicieux. Nous montrons aussi que Darth Fader permet d’éliminer le continuum des spectres à bas rapport signal à bruit, ce qui rend possible l’estimation du décalage vers le rouge par corrélation croisée. Enfin, nous montrons sur des spectres de test issues du relevé WiggleZ que notre algorithme est capable d’analyser une part importante du relevé de façon autonome avec une haute précision, sans nécessiter d'inspection visuelle (alors que les données WiggleZ ont à l’origine été entièrement soumises à l’inspection visuelle). En conclusion, Darth Fader est un algorithme prometteur pour l’analyse des grands relevés de galaxies, en particulier pour exploiter les objets à faible rapport signal à bruit qui sont habituellement simplement ignorésSummary: Redshift is the primary measure by which astronomers can map the Universe in the radial direction. In order to test the assumptions of homogeneity and isotropy, accurate redshifts of galaxies are needed, and for a great many of them. Additionally different cosmological models can only be distinguished by careful observations of the large scale structure traced by these galaxies. Large sky surveys are the only mechanism by which redshifts for a large number of galaxies can be obtained. Accurate redshift estimation is additionally required for many other fields of astronomy including but not limited to: weak lensing, studies of dark matter haloes, galaxy morphology studies, chemical evolution studies, photometric calibration, and studies of large scale structure and galaxy clustering.Problems exist in all surveys at the dim limit of observation, which usually corresponds to the higher redshift objects in the survey, where noise becomes problematic. Magnitude or signal-to-noise ratio cuts are often employed in order to eliminate potentially troublesome objects; such a procedure is a blunt tool for separating good redshift candidates from ones likely to be inaccurate.In this thesis we develop an algorithm to tackle redshift estimation of galaxy spectra in the low signal-to-noise regime. The first part of this thesis introduces the concepts of denoising, particularly False Detection Rate denoising, wavelet transforms and redshift estimation algorithms. The second part details how these concepts are united into the Darth Fader (Denoised and Automatic Redshifts THresholded with a FAlse DEtection Rate) algorithm. The final parts of this thesis apply the algorithm both to idealised synthetic data generated from the COSMOS Mock Catalogue, and to a subset of real data from the WiggleZ survey.We show that Darth Fader can operate effectively at low signal-to-noise given an appropriate choice of FDR parameter for denoising, and an appropriate feature-counting criterion. We also show that Darth Fader can remove the continua of spectra effectively at low signal-to-noise for the purposes of redshift estimation by cross-correlation. Additionally we show from tests on spectra from the WiggleZ survey that our algorithm has the ability to process a substantial subset of that data without the need for visual inspection (to which the entire WiggleZ spectral survey has been subjected), and to a high degree of accuracy. We conclude that the Darth Fader algorithm has potential to be used in large-sky survey pipelines, particularly where signal-to-noise is expected to be poor
40
Xingwen, Ding, Chang Hongyu, and Chen Ming. "OPTIMUM PARAMETER COMBINATIONS FOR MULTI-H FULL RESPONSE CONTINUOUS PHASE MODULATION." International Foundation for Telemetering, 2017. http://hdl.handle.net/10150/626964.
Повний текст джерелаАнотація:
According to IRIG 106-15, the ARTM CPM waveform, a kind of multi-h partial response continuous phase modulation (CPM), has almost three times the spectral efficiency of PCM/FM and approximately the same detection efficiency of PCM/FM. But the improved spectral efficiency of ARTM CPM comes at the price of computational complexity in the receiver. This paper focuses on multi-h full response CPM, which generally has less detection complexity than ARTM CPM, but also has good spectral efficiency and detection efficiency. Taking the minimum Euclidean distance, spectral efficiency and detection complexity as judgment criterions, optimum parameter combinations for multi-h full response CPM are presented.
41
Steiner, Rachel. "Effects of Atomoxetine and 7-NINA on Serotonin 1B-Induced Autism-like Non-Selective Attention Deficits in Mice: An Investigation of Novel Treatments." Wittenberg University Honors Theses / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wuhonors1469116290.
Повний текст джерела
42
JESECK, PASCAL. "Interferometrie de fourier, sous ballon stratospherique, en vue de la mesure a distance par spectroscopie infrarouge en absorption et a haute resolution spectrale, des constituants minoritaires de l'atmosphere terrestre." Paris 7, 1996. http://www.theses.fr/1996PA077073.
Повний текст джерелаАнотація:
L'objet de ce travail de these a ete de developper un instrument permettant l'enregistrement de spectres infrarouges par occultation solaire. Ce spectrometre a transformee de fourier embarque sous ballon stratospherique a enregistre grace a l'utilisation d'une optique de sortie a deux detecteurs (hgcdte et insb ou deux detecteurs si), des spectres a haute resolution couvrant les signatures spectrales de nombreuses molecules ayant un role important dans la chimie de l'ozone stratospherique. Ces spectres ont ete enregistres par visee en dessous et au-dessus de l'horizontal local et permettent de mesurer les profils verticaux de concentration de hcl, clono2, o3, ch4, n2o, no2, hno3 et hf qui interviennent dans la physico-chimie de la stratosphere. Pour les spectres enregistres a haute altitude (pour une faible masse d'air), la reponse du detecteur hgcdte est devenue nonlineaire. Nous avons mis au point une chaine de programmes permettant le calcul les spectres et corrigeant notamment sur l'interferogramme la nonlinearite du detecteur hgcdte
43
Stolle, Martin Tobias. "Vers le vol à voile longue distance pour drones autonomes." Thesis, Toulouse, ISAE, 2017. http://www.theses.fr/2017ESAE0006.
Повний текст джерелаАнотація:
Les petit drones à voilure fixe rendent services aux secteurs de la recherche, de l'armée et de l'industrie, mais souffrent toujours de portée et de charge utile limitées. Le vol thermique permet de réduire la consommation d'énergie. Cependant,sans télédétection d'ascendances, un drone ne peut bénéficier d'une ascendance qu'en la rencontrant par hasard. Dans cette thèse, un nouveau cadre pour le vol à voile longue distance autonome est élaboré, permettant à un drone planeur de localiser visuellement des ascendances sous-cumulus et d’en récolter l'énergie de manière efficace. S'appuyant sur le filtre de Kalman non parfumé, une méthode de vision monoculaire est établie pour l'estimation des paramètres d’ascendances. Sa capacité de fournir des estimations convergentes et cohérentes est évaluée par des simulations Monte Carlo. Les incertitudes de modèle, le bruit de traitement de l'image et les trajectoires de l'observateur peuvent dégrader ces estimés. Par conséquent, un deuxième axe de cette thèse est la conception d'un planificateur de trajectoire robuste basé sur des cartes d'ascendances. Le planificateur fait le compromis entre le temps de vol et le risque d’un atterrissage forcé dans les champs tout en tenant compte des incertitudes d'estimation dans le processus de prise de décision. Il est illustré que la charge de calcul du planificateur de trajectoire proposé est réalisable sur une plate-forme informatique peu coûteuse. Les algorithmes proposés d’estimation ainsi que de planification sont évalués conjointement dans un simulateur de vol à 6 axes, mettant en évidence des améliorations significatives par rapport aux vols à voile longue distance autonomes actuelsSmall fixed-wing Unmanned Aerial Vehicles (UAVs) provide utility to research, military, and industrial sectors at comparablyreasonable cost, but still suffer from both limited operational ranges and payload capacities. Thermal soaring flight for UAVsoffers a significant potential to reduce the energy consumption. However, without remote sensing of updrafts, a glider UAVcan only benefit from an updraft when encountering it by chance. In this thesis, a new framework for autonomous cross-country soaring is elaborated, enabling a glider UAV to visually localize sub-cumulus thermal updrafts and to efficiently gain energy from them.Relying on the Unscented Kalman Filter, a monocular vision-based method is established, for remotely estimatingsub-cumulus updraft parameters. Its capability of providing convergent and consistent state estimates is assessed relyingon Monte Carlo Simulations. Model uncertainties, image processing noise, and poor observer trajectories can degrade theestimated updraft parameters. Therefore, a second focus of this thesis is the design of a robust probabilistic path plannerfor map-based autonomous cross-country soaring. The proposed path planner balances between the flight time and theoutlanding risk by taking into account the estimation uncertainties in the decision making process. The suggested updraftestimation and path planning algorithms are jointly assessed in a 6 Degrees Of Freedom simulator, highlighting significantperformance improvements with respect to state of the art approaches in autonomous cross-country soaring while it is alsoshown that the path planner is implementable on a low-cost computer platform
44
Tujkovic, D. (Djordje). "Space-time turbo coded modulation for wireless communication systems." Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:9514269977.
Повний текст джерелаАнотація:
Abstract
High computational complexity constrains truly exhaustive computer searches for good space-time (ST) coded modulations mostly to low constraint length space-time trellis codes (STTrCs). Such codes are primarily devised to achieve maximum transmit diversity gain. Due to their low memory order, optimization based on the design criterion of secondary importance typically results in rather modest coding gains. As another disadvantage of limited freedom, the different low memory order STTrCs are almost exclusively constructed for either slow or fast fading channels. Therefore in practical applications characterized by extremely variable Doppler frequencies, the codes typically fail to demonstrate desired robustness. On the other hand, the main drawback of eventually increased constraint lengths is the prohibitively large decoding complexity, which may increase exponentially if optimal maximum-likelihood decoding (MLD) is applied at the receiver. Therefore, robust ST coded modulation schemes with large equivalent memory orders structured as to allow sub-optimal, low complexity, iterative decoding are needed.
To address the aforementioned issues, this thesis proposes parallel concatenated space-time turbo coded modulation (STTuCM). It is among the earliest multiple-input multiple-output (MIMO) coded modulation designs built on the intersection of ST coding and turbo coding. The systematic procedure for building an equivalent recursive STTrC (Rec-STTrC) based on the trellis diagram of an arbitrary non-recursive STTrC is first introduced. The parallel concatenation of punctured constituent Rec-STTrCs designed upon the non-recursive Tarokh et al. STTrCs (Tarokh-STTrCs) is evaluated under different narrow-band frequency flat block fading channels. Combined with novel transceiver designs, the applications for future wide-band code division multiple access (WCDMA) and orthogonal frequency division multiplexing (OFDM) based broadband radio communication systems are considered. The distance spectrum (DS) interpretation of the STTuCM and union bound (UB) performance analysis over slow and fast fading channels reveal the importance of multiplicities in the ST coding design. The modified design criteria for space-time codes (STCs) are introduced that capture the joint effects of error coefficients and multiplicities in the two dimensional DS of a code. Applied to STTuCM, such DS optimization resulted in a new set of constituent codes (CCs) for improved and robust performance over both slow and fast fading channels. A recursive systematic form with a primitive equivalent feedback polynomial is assumed for CCs to assure good convergence in iterative decoding. To justify such assumptions, the iterative decoding convergence analysis based on the Gaussian approximation of the extrinsic information is performed. The DS interpretation, introduced with respect to an arbitrary defined effective Hamming distance (EHD) and effective product distance (EPD), is applicable to the general class of geometrically non-uniform (GNU) CCs. With no constrains on the implemented information interleaving, the STTuCM constructed from newly designed CCs achieves full spatial diversity over quasi-static fading channels, the condition commonly identified as the most restrictive for robust performance over a variety of Doppler spreads. Finally, the impact of bit-wise and symbol-wise information interleaving on the performance of STTuCM is studied.
45
Rodgers, Alexis D. "EXAMINING AN ASYNCHRONOUS GROUP DISCUSSION BOARD ADAPTATION OF A PARENT-MEDIATED BEHAVIOR INTERVENTION FOR CHILDREN WITH AUTISM SPECTRUM DISORDERS." UKnowledge, 2018. https://uknowledge.uky.edu/edp_etds/76.
Повний текст джерелаАнотація:
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social and communication deficits, as well as restricted, repetitive, and stereotyped behaviors, interests, and activities (American Psychiatric Association, 2013). Although important relationships have been shown and described among the issues of challenging behavior, parent stress, and parenting sense of competence for families of children with ASD, there is a shortage of intervention programs appropriately suited for families which target these issues. Some programs have been developed and tested, but none is directly applicable for the target population. This is notable because of the connections drawn in the literature between families of children with ASD and the issues of challenging child behavior, parent stress, and parent sense of competence. Additionally, access to ASD-trained clinicians and research supported delivery options for families in rural areas is severely limited.
COMPASS for Hope (C-HOPE) is an 8-week parent intervention program that was developed with the option of telehealth or face-to-face delivery. This study examined an asynchronous group discussion board adaptation of C-HOPE, which was developed to further support underserved families. Three main hypotheses were made: (1) Parents will report less challenging child behaviors post-intervention; (2) Parents will report lower levels of stress post-intervention; and (3) Parents will report higher sense of competency post-intervention. With a small sample size of 10, paired-samples t-tests were conducted and effect sizes were calculated to compare the pre- and post-intervention scores for challenging child behavior, parent stress, and parenting sense of competence.
There was a statistically significant difference in the scores for challenging child behavior pre-intervention (M = 146.40, SD = 35.36) and post-intervention (M = 123.10, SD = 28.35); t(9) = 3.05, p = 0.01. The effect size for this analysis (d = 0.73) was found to fall between Cohen’s (1988) convention for a medium (d = 0.50) to large (d = 0.80) effect. There was also a statistically significant difference in the scores for parent stress pre-intervention (M = 122.60, SD = 25.73) and post-intervention (M = 109.50, SD = 26.47); t(9) = 2.51, p = 0.03. There was a medium effect size for this analysis (d = 0.50). There was not a significant difference in the scores for parenting sense of competence pre-intervention (M = 55.20, SD = 17.59) and post-intervention (M = 50.50, SD = 17.51); t(9) = 1.11, p = 0.30. Additionally, treatment adherence and social validity for the intervention were acceptable. The implications of these findings are discussed.
46
Fiori, Costantino. "Oxydation du silicium et modification de l'ordre à courte distance dans les oxydes de silicium induits par un rayonnement laser ultra violet." Grenoble 1, 1986. http://www.theses.fr/1986GRE10131.
Повний текст джерелаАнотація:
Etude par spectrometrie auger de la structure de la surface de si(111) faiblement recouverte d'oxygene sec. L'irradiation par un faible flux de photons uv induit d'importants rearrangements atomiques dans la phase adsorbees avec formation d'une monocouche tres desordonnee de sio::(2) se transformant en sio::(2) amorphe stable apres un recuit thermique a 949 k. L'irradiation de ces couches par un rayonnement laser uv les rend instables. Formation d'une forte densite de defauts structuraux. Etablissement d'une correlation entre les phenomenes physiques evoques
47
Ullah, Farooq Kifayat. "New Generation of Vibration Experiments Remotely Controlled Over the Internet:Development of Labview based Spectrum Analyzer and Interface." Thesis, Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-2509.
Повний текст джерелаАнотація:
This thesis is part of the on going work at BTH (Blekinge Technical University) to develop a remote lab for Sound and Vibration Experiments. The aim of this undertaking is to develop a Spectrum Analyzer that can simultaneously take inputs from 10 sensors and be able to measure the Power Spectral Density, Cross correlation, Frequency Response Functions (FRF) and coherence. The Interface and analysis algorithms are developed inLabview programming language. The thesis starts by introducing the overall aim of the project and its scope, the place of this particular thesis in the whole picture and the algorithms used for analysis are introduced. In the second part of the thesis the development of the software is explained and the main aim is to thoroughly document the software. This part of the thesis explains Labview programming concepts in detail to make it easier for other students who want to undertake theses to continue this work and who may not have experience of Labview programming.Two versions of the spectrum analyzer were developed. The third part explains theexperimental set up and results obtained and compares measurements to those obtained using other spectrum analyzers. An accurate Spectrum Analyzer Virtual Instrument has been developed and tested during this thesis project and it can be used as a component of the proposed Sound and vibration analysis laboratory and also for general Spectral Analysis tasks.Good guide to learn Labview and sound and vibration analysis..
fkul08@gmail.com Is my email and i can be contacted via messenger usually at farooq_kifayat@hotmail.com And i can also be contacted via skype using farooqkifayat as my name. I move around a lot so i have no permanent address that stays longer than half a year .
48
Sousa, Aline Farias Gomes de. "Enumera??o de espectro de dist?ncias de esquemas de modula??o codificada em treli?a empregando codifica??o turbo." Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15321.
Повний текст джерелаАнотація:
Made available in DSpace on 2014-12-17T14:55:43Z (GMT). No. of bitstreams: 1
AlineFGS_DISSERT.pdf: 1151209 bytes, checksum: 4ae192dd7519e3e14977154f7b70d951 (MD5)
Previous issue date: 2010-06-14Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
In this work, a performance analysis of transmission schemes employing turbo trellis coded modulation. In general, the performance analysis of such schemes is guided by evaluating the error probability of these schemes. The exact evaluation of this probability is very complex and inefficient from the computational point of view, a widely used alternative is the use of union bound of error probability, because of its easy implementation and computational produce bounds that converge quickly. Since it is the union bound, it should use to expurge some elements of distance spectrum to obtain a tight bound. The main contribution of this work is that the listing proposal is carried out from the puncturing at the level of symbol rather than bit-level as in most works of literature. The main reason for using the symbol level puncturing lies in the fact that the enummerating function of the turbo scheme is obtained directly from complex sequences of signals through the trellis and not indirectly from the binary sequences that require further binary to complex mapping, as proposed by previous works. Thus, algorithms can be applied through matrix from the adjacency matrix, which is obtained by calculating the distances of the complex sequences of the trellis. This work also presents two matrix algorithms for state reduction and the evaluation of the transfer function of this. The results presented in comparisons of the bounds obtained using the proposed technique with some turbo codes of the literature corroborate the proposition of this paper that the expurgated bounds obtained are quite tight and matrix algorithms are easily implemented in any programming software language
Neste trabalho ? feita uma an?lise de desempenho de esquemas de transmiss?o empregando modula??o codificada turbo em treli?a. Em geral, a an?lise de desempenho de tais esquemas ? guiada pelo c?lculo da probabilidade de erro destes esquemas. O c?lculo exato desta probabilidade ? muito complexo e ineficiente sob o ponto de vista computacional, uma alternativa muito utilizada ? o emprego de limitante da uni?o da probabilidade de erro, por ser de f?cil implementa??o computacional e produzir limitantes que convergem rapidamente. Por se tratar do limitante da uni?o, este deve utilizar de expurgo de alguns elementos do espectro de dist?ncias do c?digo para a obten??o de um limitante apertado. A principal contribui??o deste trabalho ? que a enumera??o proposta ? realizada a partir da perfura??o a n?vel de s?mbolo e n?o a n?vel de bit como na maioria dos trabalhos da literatura. O principal motivo do uso da perfura??o a n?vel de s?mbolo reside no fato que a fun??o enumeradora do esquema turbo ? obtida diretamente das seq??ncias complexas de sinais atrav?s da treli?a e n?o de forma indireta a partir da seq??ncias bin?rias que exigem posterior mapeando bin?rio para complexo, como proposto por trabalhos anteriores. Assim, podem ser aplicados algoritmos completamente matriciais a partir da matriz adjac?ncia, que ? obtida a partir do c?lculo das dist?ncias das seq??ncias complexas da treli?a e n?o das seq??ncias bin?rias. Neste trabalho tamb?m s?o apresentados dois algoritmos matriciais de redu??o de estados do codificador bem como do c?lculo da fun??o de transfer?ncia deste. Os resultados apresentados em forma de compara??es dos limitantes obtidos utilizando a t?cnica proposta com alguns c?digos turbo da literatura corroboram com a proposi??o deste trabalho que os limitantes expurgados obtidos s?o apertados e os algoritmos completamente matriciais s?o facilmente implementados em qualquer software de programa??o simb?lica
49
Yu, Wenhui. "Mesure de distance absolue utilisant l'interférométrie à balayage de longueur d'onde étalonnée par un peigne de fréquences." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAD005/document.
Повний текст джерелаАнотація:
Dans cette thèse, nous avons mis en oeuvre un système de mesure de distance absolue (Absolute Distance Measurement, ADM) de haute précision utilisant l'interférométrie à balayage de fréquence (Frequency Sweeping Interferometry, FSI). La technique FSI exige que la plage de réglage de fréquence du laser balayé soit mesurée avec une précision élevée, ce qui est difficile en raison de l'absence d'un moyen simple de mesurer la haute fréquence d'un laser en temps réel. Dans cette thèse, un peigne de fréquence a été utilisé comme règle de fréquence lumière pour mesurer la plage de réglage de la fréquence du laser à balayage. Un peigne de fréquence formé par un laser femtoseconde est constitué de millions de lignes de peigne régulièrement espacées, ce qui permet de le considérer comme une règle de fréquence de la lumière. La calibration de fréquence a été réalisée en filtrant le signal hétérodyne entre le laser à balayage et les lignes de peigne en utilisant un filtre passe-bande étroit. Cette approche nous permet de détecter le signal d'étalonnage lorsque la fréquence du laser à balayage est proche d'une ligne en peigne. Etant donné que l’intervalle de fréquence entre les lignes de peigne peut être mesuré avec précision ou activement verrouillé en phase par rapport à un oscillateur radiofréquence (RF) stable, la plage d ’ accord du laser à balayage peut être mesurée avec une grande précision. En particulier, chacun des deux pics d’étalonnage peut être utilisé dans le calcul de la distance, ce que nous appelons des «sous-mesures» en un seul balayage. Combinée au grand nombre de lignes de peigne, la moyenne des sous-mesures améliore considérablement la précision des mesures sans balayage multiple. Dans la thèse, la condition de détection et les caractéristiques du signal hétérodyne entre le laser à balayage et la ligne de peigne sont présentées. Une conception de filtre pour filtrer le signal hétérodyne est réalisée. Un travail de modélisation concernant l'effet du bruit de phase des lasers sur la distorsion d'enveloppe du pic d'étalonnage a été présenté. Des travaux expérimentaux basés sur les concepts de mesure ont été réalisés. Il montre que l'utilisation du schéma de mesure proposé peut considérablement améliorer la précision de la mesure de distance. Dans l’une des mesures, une précision de 30 nm pour une distance d’environ 0,8 m, correspondant à une incertitude relative de 37 ppm (part-perbillion) a été obtenue. Le résultat a été obtenu sur la base d'une méthode de traitement du signal de comptage de franges. La grande précision a été obtenue grâce au grand nombre de sous-mesures et à la stabilité des lignes de peigne régulièrement espacées. Nous avons constaté que la mesure de vibration de la cible peut également être effectuée en prenant avantage des lignes de peigne denses. Une sensibilité élevée, limitée à 1,7 nm efficace en bruit, de la mesure des vibrations a été atteinte. Ce résultat nous permet de surveiller la vibration de la cible, ce qui est un problème important de la technique FSIIn this thesis, we implemented a high-precision absolute distance measurement (ADM) system using frequency sweeping interferometry (FSI). The FSI technique requires the frequency tuning range of the swept laser to be measured with high accuracy and precision, which is challenging due to the lack of an easy way to measure the high frequency of a laser in real time. In this thesis, a frequency comb has been used as the light frequency ruler for measuring the frequency tuning range of the sweeping laser. A frequency comb formed by a femtosecond laser consists millions of evenly spaced comb lines so that can be regarded as a light frequency ruler. The frequency calibration was realized by filtering the heterodyne signal between the sweeping laser and the comb lines using a narrow bandpass filter. This approach allows us to detect the calibration signal when the frequency of the sweeping laser is in the vicinity of a comb line. As the frequency interval between the comb lines space can be precisely measured or actively phase-locked against a stable radio-frequency (RF) oscillator, the tuning range of the sweeping laser could be measured with high accuracy. Especially, each two calibration peaks can be used in the calculation of distance, which we call sub-measurements in a single sweeping. Combined with the large number of the comb lines, averaging of the sub-measurements improves greatly the measurement precision without multiple sweeping. In the thesis, the condition of detecting and the characteristics of the heterodyne signal between the sweeping laser and the comb line are presented. A filter design for filtering the heterodyne signal is performed. A modeling work concerning the effect of the phase noise of lasers on the envelope distortion of the calibration peak has been presented. Experimental works based on the measurement concepts have been carried out. It shows that using the proposed measurement scheme can greatly improve the distance measurement precision. In one of the measurements, a precision of 30 nm for a distance around 0.8 m, corresponding to 37 ppb (part-per-billion) relative uncertainty has been achieved. The result was obtained based on a fringe counting signal processing method. The high precision was obtained thanks to the large number of sub-measurements and the stability of the evenly spaced comb lines. We have found that vibration measurement of the target can be also performed taking the advantage of the dense comb lines. A high sensitivity, limited by 1.7 nm noise RMS, of vibration measurement has been achieved. This result allows us to monitor the vibration of the target, which is an important issue of FSI technique
50
CHAOUCH, CHAKIB. "Cyber-physical systems in the framework of audio song recognition and reliability engineering." Doctoral thesis, Chakib Chaouch, 2021. http://hdl.handle.net/11570/3210939.
Повний текст джерелаАнотація:
Music Information Retrieval (MIR) is the interdisciplinary discipline of extracting information from music, and it is the topic of our research. The MIR system faces a significant issue in dealing with various genres of music. Music retrieval aims at helping end-users search and finds a desired piece of music from an extensive database. In other words, Music Information retrieval tries to make music information more accessible to listeners, musicians, and data scientists. The challenges and research problems that an audio recognition system faces in everyday use might come in a variety of forms. Significant aspects are: near-identical original audio, noise, and spectral or temporal distortion invariance, a minimal length of song track required for identification, retrieval speed, and processing load are all important factors.
In order to overcome these problems and achieve our goal, a Short Time Power Spectral Density (ST-PSD) fingerprinting is proposed as an innovative, efficient, highly accurate, and exact fingerprinting approach. To maintain high
accuracy and specificity on hard datasets, we propose matching features based on an efficient hamming distance search on a binary type fingerprint, followed by a verification step for match hypotheses.
We gradually improve this system by adding additional components like the Mel frequency bank filter and progressive probability evaluation score.
Besides, we introduce a new fingerprint generation method and we present the fundamentals
for generating fingerprints and we show they are robust in the song recognition process. Then, we evaluate the performance of our proposed method using a scoring measure based on the accuracy classification of thousands of Songs.
Our purpose is to communicate the effectiveness of the fingerprints generated with two proposed approaches; we will show that, even without any optimized searching algorithm, the accuracy obtained in recognizing pieces of songs is very
good, thus making the apprapproachropose a good candidate to be used in an
effective song recognition process.
I will be discussing another area of research that was done as part of my period abroad at Duke University, USA, as part of an exchange program. The topic related to reliability engineering has been incorporated. The first part focuses on the reliability and interval reliability of the Phased Mission System (PMS) with repairable components and disconnected phases, using analytical modeling as a state space-oriented method using the Continuous-time Markov
chain (CTMC). The second aspect focuses on non-repairable multi-state components PMS, in which we present a practical case study of a spacecraft satellite that was used to demonstrate only the (PMS-BDD) method proposed with the implementation of Sharpe tools based on (FT) configuration in order to demonstrate the system’s reliability/unreliability in this case.