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1
Heidenreich, Ralf, Dirk Schmidt, Andreas Böhme, Torsten Moczigemba, and Peter Fleischer. "Diffuse Staubemissionen." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-62943.
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Mit einer mobilen Probenahme- bzw. Messeinrichtung untersuchte das Institut für Luft- und Kältetechnik Dresden (ILK) im Auftrag des LfULG diffuse Staubemissionen in einer Bauschuttrecyclinganlage.
Neben der mobilen Messung mit dem Partikelmessgerät APS 3321 kamen stationäre Messeinrichtungen (Impaktoren u. a.) am Messort zum Einsatz.
Im Ergebnis wurden repräsentative Feinstaub- sowie Quarzstaubimmissionen für eine Bauschuttrecyclinganlage ermittelt.
In einem weiteren Schritt wurden die Messergebnisse nachgerechnet. Geprüft wurde, ob mit einer Immissionsprognose nach TA Luft auf Basis von Emissionsfaktoren nach VDI 3790 Blatt 3, ähnliche Ergebnisse ermittelt werden.
Anhand der durchgeführten Rechnungen wird eingeschätzt, dass die berechneten Werte in der Regel über den Messergebnissen, aber mit einer akzeptablen Toleranz, liegen. Bei Anpassung der Rechenparameter an die Betriebsbedingungen vor Ort wird eine relativ gute Übereinstimmung erzielt.
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Laouar, Tayeb. "Contribution à l'étude de l'approximation diffuse : auto-adaptativité en éléments diffus." Compiègne, 1996. http://www.theses.fr/1996COMPD891.
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Ce travail constitue une contribution dans le développement des moyens de résolution des systèmes d'Équations aux Dérivées Partielles (EDP) en utilisant la méthode d'approximation diffuse (A. D. ). Il s'articule autour du thème suivant : Calcul auto-adaptatif en éléments diffus sur la résolution des EDP pour des problèmes mécaniques. Tout d'abord, nous nous sommes attachés à souligner les principes généraux ainsi que les choix fondamentaux définissant l'A. D. (choix des fonctions poids, choix de la base,. . . ). Ensuite, étant donné que l'A. D. N'est pas interpolant, nous avons introduit la notion d'interpolation diffuse. Enfin nous avons explicité le contrôle d'erreur bidimensionnel en A. D. La deuxième partie porte sur la résolution d'EDP par la méthode des éléments diffus (E. D. ). Nous proposons un outil permettant de contrôler a posteriori et auto-adaptativement la qualité d'une solution E. D. Nous avons développé une stratégie de raffinement. Les premiers exemples traités nous ont révélé des problèmes au niveau de l'intégration numérique : des modes parasites apparaissent. Nous avons proposé plusieurs stratégies d'amélioration, par exemple en construisant des fonctions de forme avec des supports simples. Malheureusement le problème d'intégration persiste. Afin de remédier à ce problème, nous avons montré explicitement que l'on doit imposer aux fonctions de forme diffuses une condition supplémentaire qui est la traduction d'une formule de conservation. Le choix que nous avons fait consiste à éviter l'intégration par parties lors de la formulation variationnelle. Nous avons obtenu des résultats très satisfaisants tant au niveau de résolution des EDP qu'au niveau d'étude des problèmes thermique ou mécanique. Au cours de ce travail on a toujours procédé à des comparaisons avec la méthode des éléments finis. Le modèle éléments diffus semble être performant par rapport au modèle éléments finis sur les exemples traités.
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Bailey, Amanda. "Probing the diffuse interstellar medium with diffuse interstellar bands." Thesis, Keele University, 2014. http://eprints.keele.ac.uk/1244/.
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This work investigates the small scale structure of the Diffuse Interstellar Medium. To do this optical spectroscopy is used to obtain spectra of early type stars which are used as background targets with which the Diffuse Interstellar Medium (ISM) is probed. The spectra obtained contain the highly diagnostic Diffuse Interstellar Bands (DIBs), Na i D and Ca ii lines. The maps I present here are of the Local Bubble, the Small Magellanic Cloud and the Large Magellanic Cloud. These are the first DIB maps of the solar neighbourhood and large portions of external galaxies. The spectra were obtained with the New Technology Telecsope (NTT) at La Silla Observatory in Chile (Local Bubble survey) and at the Anglo-Australian Telescope (AAT) at Siding Spring Observatory, NSW, Australia. The NTT spectra are long slit spectra of 239 individual targets, whilst the AAT spectra were obtained with the multi-fibre spectrograph 2dF/AAOmega (about 350 targets in each of the Magellanic Clouds). I have successfully used the 5780 and 5797˚A DIBs to map the ISM in the Local Bubble and the Magellanic Clouds. The 5797˚A DIB traced neutral structures whereas the 5780˚A DIB traced warmer and/or more highly irradiated gas, possibly residing in the skins of those neutral clouds It showed a more highly structured Local Bubble than revealed by the sodium maps, on sub parsec scales; tracing the walls of the Bubble and clearly showing the Bubble opening out into the Halo. In the Magellanic Clouds the DIBs trace molecular clouds surrounding regions of active star formation; they are weak or absent in quiescent molecular cloud complexes and hot gas bubbles.
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Hibbins, Robert E. "Diffuse interstellar bands." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307820.
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Ibbett, R. N. "Infrared diffuse reflectance spectroscopy." Thesis, University of East Anglia, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382895.
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Cernicharo, José. "Matière diffuse et molécules interstellaires." Phd thesis, Université Paris-Diderot - Paris VII, 1988. http://tel.archives-ouvertes.fr/tel-00725658.
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La structure des nuages sombres de la région Taurus-Auriga-perseus et les causes des différences chimiques observées sont etudiées à l'aide de données radio, IR et optique. Des observations millimétriques ont permis de réaliser des cartes détaillées enCO de ce complexe moléculaire interstellaire. De nouvelles molécules métalliques ont été détectées (CLNA,CLK,CLAL, et FAL) ainsi que des isotopes de SICC et HCCCH. Des travaux instrumentaux pour différents radiotélescopes sont aussi décrits.
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Schöps, Andreas. "Diffuse Röntgenstreuung an binären Legierungen." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=973255552.
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Behrooz, Ali. "Multiplexed fluorescence diffuse optical tomography." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50401.
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Fluorescence tomography (FT) is an emerging non-invasive in vivo molecular imaging modality that aims at quantification and three-dimensional (3D) localization of fluorescent tagged inclusions, such as cancer lesions and drug molecules, buried deep in human and animal subjects. Depth-resolved 3D reconstruction of fluorescent inclusions distributed over the volume of optically turbid biological tissue using the diffuse fluorescent photons detected on the skin poses a highly ill-conditioned problem, as depth information must be extracted from boundary data. Due to this ill-posed nature of FT reconstructions, noise and errors in the data can severely impair the accuracy of the 3D reconstructions. Consequently, improvements in the signal-to-noise ratio (SNR) of the data significantly enhance the quality of the FT reconstructions. Furthermore, enhancing the SNR of the FT data can greatly contribute to the speed of FT scans. The pivotal factor in the SNR of the FT data is the power of the radiation illuminating the subject and exciting the administered fluorescent agents. In existing single-point illumination FT systems, the illumination power level is limited by the skin maximum radiation exposure levels. In this research, a multiplexed architecture governed by the Hadamard transform was conceptualized, developed, and experimentally implemented for orders-of-magnitude enhancement of the SNR and the robustness of FT reconstructions. The multiplexed FT system allows for Hadamard-coded multi-point illumination of the subject while maintaining the maximal information content of the FT data. The significant improvements offered by the multiplexed FT system were validated by numerical and experimental studies carried out using a custom-built multiplexed FT system developed exclusively in this work. The studies indicate that Hadamard multiplexing offers significantly enhanced robustness in reconstructing deep fluorescent inclusions from low-SNR FT data.
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Cernicharo, José. "Matière diffuse et molécules interstellaires." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37612561n.
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Schöps, Andreas. "Diffuse Röntgenstreuung an binären Legierungen." [S.l. : s.n.], 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11612013.
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Cernicharo, José. "Matiere diffuse et molecules interstellaires." Paris 7, 1988. http://www.theses.fr/1988PA077028.
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La structure des nuages sombres de la region taurus-auriga-perseus et les causes des differences chimiques observees sont etudiees a l'aide de donnees radio, ir et optique. Des observations millimetriques ont permis de realiser des cartes detaillees en co de ce complexe moleculaire interstellaire. De nouvelles molecules metalliques ont ete detectees (clna, clk, clal et fal) ainsi que des isotopes de sicc et hccch. Des travaux instrumentaux pour differents radiotelescopes sont aussi decrits
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Lines, Richard Stephen George. "The application of a diffuse field reciprocity relation to a new set of diffuse fields." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609644.
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Schröder, Marie. "Die diffuse postoperative Peritonitis. Wertigkeit diagnostischer Parameter und Prognose im Vergleich zur ambulant erworbenen diffusen Peritonitits." Lübeck Zentrale Hochschulbibliothek Lübeck, 2010. http://d-nb.info/1002838207/34.
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Everitt, David Lewis. "Imaging of tissue-like media with diffuse light : analysis and optimization of a diffuse photon tomography /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.
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Savignat, Jean-Michel. "Approximation diffuse Hermite et ses applications." Phd thesis, École Nationale Supérieure des Mines de Paris, 2000. http://pastel.archives-ouvertes.fr/pastel-00577930.
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De nombreuses techniques de résolution d'équations aux dérivées partielles sans maillage ont été développées dans la dernière décennie, proposant une alternative attrayante lorsque les éléments finis atteignent leurs limites. Notre travail se concentre sur l'étude de l'approximation diffuse, de ses applications au lissage et a la résolution des équations différentielles : les éléments diffus. Cependant, les solutions proposées s'appliquent aussi à d'autres méthodes et de nombreux résultats numériques illustrent chaque développement théorique. Dans un premier temps, nous étudions les techniques d'approximation sans maillage et les comparons à l'aide d'une méthode hybride. L'approximation myope est construite en modifiant le critère de construction des splines et montre ainsi la différence de nature entre moindres carres glissants et interpolateurs radiaux (krigeage, splines). Nous développons ensuite l'approximation diffuse Hermite dont l'application au calcul de la courbure des surfaces triangulées aboutit à une technique de haute résolution. Un algorithme de reverse engineering de modèle CAO s'appuie sur cette nouvelle technique et met en évidence son potentiel. L'intégration numérique est un ingrédient essentiel pour une méthode sans maillage. L'analyse du patch test nous conduit a la définition d'une technique robuste et assurant de bons rangs de convergence. Nous l'appliquons à l'approximation Hermite pour construire un modèle de poutre 3d pour le forage pétrolier. Un algorithme de contact roche-structure original est propose pour ce problème.
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Trabelsi, Slim. "Services spontanés sécurisés pour l'informatique diffuse." Phd thesis, Télécom ParisTech, 2008. http://pastel.archives-ouvertes.fr/pastel-00004140.
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Le paradigme de l'informatique diffuse suppose implicitement un modèle d'interaction dynamique qui s'appuie en premier lieu sur la découverte d'applications ambiantes et d'appareils environnants. Quoique la découverte soit au cœur de tels systèmes, en particulier ceux qui s'organisent selon une architecture orientée services, le besoin de sécuriser ce composant critique et la complexité de cette tâche ont été largement sous-estimés, voire négligés jusqu'à aujourd'hui. Cette thèse s'attaque à la conception de protocoles sécurisés et d'architectures fiables pour résoudre les problèmes des techniques actuelles de découverte de service. Après avoir présenté les besoins de sécurité de ce type de protocole, nous proposons trois solutions sécurisées pour la découverte de services correspondant à des degrés divers d'organisation et d'échelle de l'infrastructure sur laquelle le mécanisme est déployé. Nous montrons tout d'abord comment le chiffrement est suffisant pour protéger des architectures décentralisées de type LAN ou WLAN en restreignant l'accès aux messages de découverte diffusés d'après une politique à base d'attributs. Nous proposons ensuite l'utilisation de politiques de découvertes comme concept essentiel à la sécurisation de la découverte de services dans les architectures centralisées qui s'appuient sur un registre comme tiers de confiance. Nous introduisons enfin une architecture pour le déploiement d'un mécanisme de découverte de services sécurisé à plus grande échelle s'appuyant sur un système d'indexation pair à pair accessible via une couche de routage anonyme. Dans une deuxième partie de la thèse, nous analysons l'efficacité des mécanismes de découverte de service sécurisée proposés par une étude de performance. Un modèle Markovien est construit afin de calculer différents paramètres de performances liées à la robustesse, la disponibilité, l'efficacité ou le coût en termes de ressources consommées lors de l'exécution d'un processus de découverte en charge normale aussi bien que soumis à une attaque de déni de service. Nous discutons finalement dans une dernière partie des problèmes de sécurité et de confiance liés à l'introduction de sensibilité contextuelle dans les mécanismes de découverte de service.
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Randeberg, Lise Lyngsnes. "Diagnostic applications of diffuse reflectance spectroscopy." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Information Technology, Mathematics and Electrical Engineering, 2005. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-691.
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This thesis covers a wide field of applications, with an emphasis on applications of reflectance spectroscopy for diagnostic purposes. Reflectance spectroscopy in the visible part of the spectrum has been proved to be a valuable tool in a variety of applications including e. g. port-wine stain diagnostics, diagnostics of liver pathology, neonatal jaundice and age determination of bruises for forensic applications.
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Villanueva, Walter. "Diffuse-Interface Simulations of Capillary Phenomena." Doctoral thesis, Stockholm : Kungl. tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4402.
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Li, Ang. "Diffuse optical tomography with multiple priors /." Thesis, Connect to Dissertations & Theses @ Tufts University, 2005.
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Thesis (Ph.D.)--Tufts University, 2005.Advisers: David A. Boas; Yaacov Shapira. Submitted to the Dept. of Physics. Includes bibliographical references (leaves 113-126). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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Graneau, P. Neal. "Ion dynamics of diffuse vacuum arcs." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306534.
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Miles, Janet R. "Diffuse interstellar absorption and emission bands." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359869.
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Mezger, Markus. "Diffuse Röntgenstreuung an Ni-Pd-Legierungen." [S.l. : s.n.], 2004. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11482135.
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Butcher, Melissa Rachelle. "Diffuse Nutrient Pollution from Residential Catchments." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5194.
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Nonpoint source nutrient pollution is diffuse pollution lacking discrete origin and conveyance. This thesis synthesizes and critically reviews research on residential nitrogen and phosphorus loss to stormwater runoff and leaching. The evaluation pulls from research covering influential socio-demographic indicators, such as use of lawn maintenance services and homeowner fertilizer practices. The extent to which such social and economic factors may influence the prevalence and fate of diffuse nutrients in stormwater runoff from residential areas has not been adequately established. Understanding the source and influencing factors of diffuse nutrient pollution is important in order to effectively protect surface and groundwater resources.
Research based on sampling campaigns of catchments, sampling of controlled turf systems and models of residential catchments were compiled for this review. Based on the compilation reviewed for this thesis, there are wide differences in approaches researchers have taken to attempt to quantify and understand diffuse nutrient pollution from residential and urban areas. There is not consistency in the chemical nitrogen or phosphorus species evaluated or in reported measurements (i.e. concentration vs. loading vs. yield).
This review revealed several important knowledge gaps. Determination of correlation between residential system nutrient loss to the environment and social factors, demographic characteristics, local fertilizer ordinances or nutrient management education programs has not been substantiated. More exploration of nutrient leaching from different soil types and turf grass species is needed to develop a complete understanding of nutrient loss from turf grass systems. Further, other specific management practices such as leaving grass clippings on lawns has not been studied in depth for a variety of soil types and grass species. There is room for improvement in future research and additional studies are needed to guide future policy and implementation of best management practices. Based on these and other findings, I recommend a concerted effort to standardize a portion of the reporting details of future stormwater research and for reevaluation of nutrient/fertilizer education efforts.
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Schröder, Marie [Verfasser]. "Die diffuse postoperative Peritonitis : Wertigkeit diagnostischer Parameter und Prognose im Vergleich zur ambulant erworbenen diffusen Peritonitits / Marie Schröder." Lübeck : Zentrale Hochschulbibliothek Lübeck, 2010. http://d-nb.info/1002838207/34.
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Van, der Klis Marije Maroeska Isis Poley. "Ag-Mn: Diffuse Röntgenstreuung unter streifendem Einfall /." Zürich : ETH, 2006. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16551.
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Drosback, Meredith Marie. "Line profiles in the diffuse interstellar bands." Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3239452.
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LaMarr, John Henry. "Diffuse light correction for field reflectance measurements." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/279899.
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The Remote Sensing Group of the Optical Sciences Center at the University of Arizona performs absolute radiometric calibration of Earth-viewing sensors using vicarious methods. The reflectance and irradiance-based methods require the nadir-view reflectance of a calibration site at sensor overpass. Errors in these reflectance data contribute directly to errors in the retrieved at sensor radiance, and therefore errors in the calibration. This research addresses two areas of improvement for the reflectance retrieval. The discreet laboratory data of the reference panel is spectrally interpolated using the measured hemispherical reflectance rather than a polynomial fit. This interpolation better fits an absorption feature of the reference material near 2200 nm. The desired reflectance is due to the directly-transmitted solar irradiance, but field measurements also include irradiance due to diffuse light. Non-lambertian properties of the reference and surface cause the ratio of the reflected total radiances to differ from the ratio of the reflected solar radiances. This difference can be corrected using additional field measurements, shaded surface/shaded-reference, output from a radiative transfer code, RTC-only, or a combination of both, shaded-reference. For the shaded-reference and RTC-only methods the shape of the bi-directional reflectance factor of the surface must be known to better than 10% to maintain a 2% accuracy for the retrievals, while the shaded-surface/shaded-reference method does not use the surface BRF. All three methods were applied to measurements of calibrated reflectance tarpaulins, and to measurements made at White Sands Missile Range. These data demonstrate that the shaded-surface/shaded-reference and RTC-only methods improve the surface reflectance retrieval, while the shaded-reference method is too sensitive to variations between the actual and modeled diffuse sky irradiance to be useful. This research represents significant improvements in the calculation of surface reflectance for vicarious calibration. The hemispherical reflectance interpolation will reduce uncertainties in the short wave infrared by 1%, and the diffuse corrections will reduce the errors in blue by 2% in some cases.
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Manning, James David. "Directional diffuse reflection from a polygon emitter." Thesis, University of Hull, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445284.
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吳子皎 and Tze-kau Ng. "A study of diffuse galactic gamma radiation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1989. http://hub.hku.hk/bib/B31209397.
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He, Lian. "NONCONTACT DIFFUSE CORRELATION TOMOGRAPHY OF BREAST TUMOR." UKnowledge, 2015. http://uknowledge.uky.edu/cbme_etds/33.
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Since aggressive cancers are frequently hypermetabolic with angiogenic vessels, quantification of blood flow (BF) can be vital for cancer diagnosis. Our laboratory has developed a noncontact diffuse correlation tomography (ncDCT) system for 3-D imaging of BF distribution in deep tissues (up to centimeters). The ncDCT system employs two sets of optical lenses to project source and detector fibers respectively onto the tissue surface, and applies finite element framework to model light transportation in complex tissue geometries. This thesis reports our first step to adapt the ncDCT system for 3-D imaging of BF contrasts in human breast tumors. A commercial 3-D camera was used to obtain breast surface geometry which was then converted to a solid volume mesh. An ncDCT probe scanned over a region of interest on the breast mesh surface and the measured boundary data were used for 3-D image reconstruction of BF distribution. This technique was tested with computer simulations and in 28 patients with breast tumors. Results from computer simulations suggest that relatively high accuracy can be achieved when the entire tumor was within the sensitive region of diffuse light. Image reconstruction with a priori knowledge of the tumor volume and location can significantly improve the accuracy in recovery of tumor BF contrasts. In vivo ncDCT imaging results from the majority of breast tumors showed higher BF contrasts in the tumor regions compared to the surrounding tissues. Reconstructed tumor depths and dimensions matched ultrasound imaging results when the tumors were within the sensitive region of light propagation. The results demonstrate that ncDCT system has the potential to image BF distributions in soft and vulnerable tissues without distorting tissue hemodynamics. In addition to this primary study, detector fibers with different modes (i.e., single-mode, few-mode, multimode) for photon collection were experimentally explored to improve the signal-to-noise ratio of diffuse correlation spectroscopy flow-oximeter measurements.
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Panagiotou, C. "Information theoretic regularization in diffuse optical tomography." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1310436/.
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Diffuse optical tomography (DOT) retrieves the spatially distributed optical characteristics of a medium from external measurements. Recovering these parameters of interest involves solving a non-linear and severely ill-posed inverse problem. In this thesis we propose methods towards the regularization of DOT via the introduction of spatially unregistered, a priori information from alternative high resolution anatomical modalities, using the information theory concepts of joint entropy (JE) and mutual information (MI). Such functionals evaluate the similarity between the reconstructed optical image and the prior image, while bypassing the multi-modality barrier manifested as the incommensurate relation between the gray value representations of corresponding anatomical features in the modalities involved. By introducing structural a priori information in the image reconstruction process, we aim to improve the spatial resolution and quantitative accuracy of the solution. A further condition for the accurate incorporation of a priori information is the establishment of correct alignment between the prior image and the probed anatomy in a common coordinate system. However, limited information regarding the probed anatomy is known prior to the reconstruction process. In this work we explore the potentiality of spatially registering the prior image simultaneously with the solution of the reconstruction process. We provide a thorough explanation of the theory from an imaging perspective, accompanied by preliminary results obtained by numerical simulations as well as experimental data. In addition we compare the performance of MI and JE. Finally, we propose a method for fast joint entropy evaluation and optimization, which we later employ for the information theoretic regularization of DOT. The main areas involved in this thesis are: inverse problems, image reconstruction & regularization, diffuse optical tomography and medical image registration.
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Malone, John Philip. "Computer-aided diagnosis of diffuse lung disease." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440143.
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Ng, Tze-kau. "A study of diffuse galactic gamma radiation /." [Hong Kong : University of Hong Kong], 1989. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12584289.
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Lieberman, Daniel Howard Shepherd J. E. "Detonation interaction with sharp and diffuse interfaces /." Diss., Pasadena, Calif. : Caltech, 2006. http://resolver.caltech.edu/CaltechETD:etd-11172005-092205.
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Pritchard, Jonathan Robin Kamionkowski Marc Kamionkowski Marc. "Extracting the cosmic history from diffuse backgrounds /." Diss., Pasadena, Calif. : California Institute of Technology, 2007. http://resolver.caltech.edu/CaltechETD:etd-05292007-112654.
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Zonios, George I. 1968. "Diffuse reflectance spectroscopy of human colon tissue." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/29636.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1998.Includes bibliographical references (p. 129-134).
Diffuse reflectance spectroscopy can provide quantitative biochemical and morphological information for the analysis of biological tissue epithelium and the detection of precancerous lesions. To investigate this, diffuse reflectance spectra were collected from adenomatous colon polyps (cancer precursors) and normal colonic tissue of patients undergoing colonoscopy. To analyze the data, an analytical model was developed based on the diffusion of light in tissue. The model was formulated in terms of the absorption and scattering properties of tissue. In the case of absorption, hemoglobin was identified as the major absorber of light, and scattering was modeled as a homogeneous of collection spherical microparticles using Mie scattering theory. The validity and accuracy of the analytical model was tested and validated on a physical tissue model (phantom) composed of polystyrene beads and hemoglobin and it was found that it is suitable for application to the tissue data. Four parameters were obtained by analyzing the tissue data using the model: hemoglobin concentration, hemoglobin oxygen saturation, effective scatterer density and size. Normal and adenoma tissue sites exhibited differences in hemoglobin concentration and effective scatterer size, in agreement with other studies which employ standard methods. These results demonstrate that diffuse reflectance can be used to obtain tissue biochemical and morphological information in vivo.
by George I. Zonios.
Ph.D.
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Codron, Clemence. "La surveillance diffuse : entre Droit et Norme." Thesis, Lille 2, 2018. http://www.theses.fr/2018LIL2D002/document.
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L’évolution des notions juridiques de vie privée et de données personnelles. A l’inverse de la littérature foisonnante sur le thème de la surveillance, il ne s’agit pas ici de mettre en avant la nécessité de trouver un équilibre entre la surveillance entendue dans sa dimension sécuritaire et la protection de la vie privée et des données personnelles, en ce qu’elle constitue une liberté fondamentale reconnue par les institutions françaises et européennes. Cette recherche d’une balance équilibrée entre sécurité et liberté doit nécessairement être dépassée pour comprendre le phénomène de surveillance diffuse. La surveillance n’est plus la simple activité de recherche de renseignements concernant un individu potentiellement dangereux. Elle s’inscrit plutôt dans la poursuite de ceque Hannah Arendt qualifie de « crise de la culture ». La surveillance diffuse est même l’une des caractéristiques de la culture contemporaine dominée par la peur, la consommation et l’aliénation par les technologies. Devenue la nouvelle norme sociale admise, la surveillance diffuse désinstitue le droit des données personnelles et la protection de la vie privée. Progressivement, elle désinstitue également le Droit au profit du libéralisme économique qu’elle porte en son seinThe purpose of this research is to understand how diffuse surveillance fits into the evolution of legal concepts of privacy and personal data. Contrary to the abundant literature on the subject of surveillance, it is not a questionhere of highlighting the need to find a balance between surveillance in its security dimension and the protection of privacy and data, as a fundamental freedom recognized by French and European institutions. This search for a balance between security and freedom must necessarily be overcome to understand the phenomenon of diffuse surveillance. Surveillance is no longer just a search for information about a potentially dangerous individual. Rather, it is a continuation of what Hannah Arendt calls the « crisis of culture ». Diffuse surveillance is even oneof the features of contemporary culture dominated by fear, consumption and alienation by technology. Having become the new accepted social norm, the diffuse surveillance deinstitutes the right of the personal data and the protection of the private life. Gradually, it also deinstitutes the Law to profit from the economic liberalism that it carries within it
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Zouaoui, Judy. "Tomographie optique diffuse multispectrale résolue en temps." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY071/document.
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La possibilité de déterminer précisément et de quantifier la composition des milieux biologiques est un défi pour l'imagerie médicale qui permettrait de diagnostiquer certaines maladies ou de mieux étudier les processus physiologiques. La tomographie optique diffuse (DOT) est une technique d'imagerie attrayante qui permet de façon non invasive, non-ionisante et potentiellement avec une grande spécificité de sonder les milieux en profondeur en utilisant la lumière dans le proche infrarouge et de reconstruire en trois dimensions leur composition. Pour obtenir les caractéristiques des chromophores endogènes (oxy- et désoxy-hémoglobine) enfouis dans un milieu très diffusant, une instrumentation optique dans le domaine temporel et multi-longueurs d'onde combinée à un algorithme de reconstruction en trois dimensions a été développée. Des mesures expérimentales ont été menées en géométrie de réflectance en éclairant avec un laser picoseconde un milieu perturbé (contenant une hétérogénéité) et en récupérant, pour plusieurs longueurs d'onde et multi-positions, la lumière rétrodiffusée via deux fibres optiques connectées à deux détecteurs dédiés et couplés à un système de comptage de photon unique. Le traitement des données de ces mesures résolues en temps a été réalisé en supposant que la propagation de la lumière est gouvernée par l'approximation de la diffusion et en utilisant une méthode basée sur la transformée de Mellin-Laplace. Des simulations et des expériences sur une gamme de milieux imitant les milieux biologiques ont démontré que cette technique médicale a le potentiel pour donner des images médicales quantitatives. Nous avons montré que l'on peut déterminer correctement la composition d'objets à 10 mm de profondeur absorbant faiblement. Pour de plus fortes profondeurs et des absorptions plus élevées, la valeur du coefficient d'absorption ou de la concentration est sous-estimée. En outre, l'imagerie multimodale apporte des améliorations dans la précision de la quantification en profondeur et donc peut être une bonne opportunité pour les futures applications cliniques de la DOTIn medical imaging, the ability to accurately retrieve and quantify the composition of turbid media is challenging and would enable to diagnose some diseases or to better study physiological processes. Diffuse optical tomography (DOT) is an attractive medical imaging technique which permits to probe in depth using near-infrared light and to reconstruct in three dimensions the composition of biological tissues non-invasively, non-ionizing and with potentially high specificity. To obtain endogenous chromophore (oxy- and desoxy-hemoglobin) features in the depth of a highly scattering medium, a multiwavelength time domain optical setup combined to a three-dimensional reconstruction algorithm was developed. Experimental measurements were conducted in reflectance geometry by illuminating a perturbed medium (with a heterogeneity) with a picosecond laser and by collecting, for several wavelengths and multi-positions, the backscattered light via two fibers connected to two dedicated detectors and coupled to a time-correlated single photon counting system. The data processing of these time-resolved measurements and those of a known reference medium was performed by supposing that the propagation of light is governed by the diffusion approximation and using a method based on Mellin-Laplace transform. Numerical and phantom experiments on series of objects similar to biological media demonstrate that this technique has the potential to give quantitative medical images. We have highlighted a correct quantification for the less absorbing objects at 10 mm depth while underestimation results at deeper depths and higher absorptions. Furthermore, the multimodal imaging brings improvements in quantification in depth and thus it can be a good opportunity to DOT for its future clinical applications
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HIMPENS, CATHERINE. "Syndrome des ongles jaunes et lymphangiopathie diffuse." Lille 2, 1989. http://www.theses.fr/1989LIL2M240.
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Makda, Nazir Ahmed Adam. "Ultra-diffuse galaxy candidatesin stripe 82 clusters." Master's thesis, Faculty of Science, 2019. https://hdl.handle.net/11427/31737.
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The evolution of galaxies in the cluster environment is a complex process, with many outstanding questions. A wide range of galaxy morphologies, colours, sizes and luminosities are found in clusters, the least studied of which are the faint galaxy populations. Studying the faint end of the galaxy luminosity distribution may provide a valuable insight into the evolution of galaxies in cluster environments. The largest of these faint galaxies are classified as Ultra-Diffuse galaxies (UDGs). UDGs are low surface brightness galaxies with a very low stellar mass component, however they have sizes comparable to the Milky Way. These galaxies are hard to detect and classify as they are very faint. To survive in the cluster environments, where they have been observed, these galaxies must contain significant amounts of dark matter as the strong tidal fields would normally tear diffuse low-mass galaxies apart. The high abundance of UDGs in clusters has only recently been recognized, therefore identifying and measuring their properties is key to understanding how they are formed and continue to exist. In this thesis, I search for low surface brightness galaxies, spanning from typical dwarf galaxies to UDGs, in 16 low redshift (z< b/a >= 0.52. The number of faint galaxies in clusters follows a power-law with respect to the cluster halo mass, N ∝ M1.05±0.45, determined through bootstrap resampling. This shows that the number of UDG candidates increases as the cluster halo mass increases.
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Sharp, Charles Michael Francis. "Clinical outcomes in diffuse parenchymal lung disease." Thesis, University of Bristol, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.723507.
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Turner, Kathryn Grace. "Ecological genomics of invasive thistle, diffuse knapweed." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/54317.
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Invasive species are able to move into new environments, with new abiotic conditions and biotic interactions, survive, and even dominate, often within a hundred years. Much research in invasion biology has assessed whether populations of invasive plants show phenotypic or evolved genetic differences in growth and reproduction compared to their native range (such as the evolution of increased competitive ability hypothesis), in an effort to understand the causal drivers of invasion. Using diffuse knapweed (Centaurea diffusa) I assessed evolution in its invaded range in multiple ways. Chapter 2 describes two greenhouse common garden experiments that evaluated phenotypic and life history trait variation between the two ranges under benign and stressful conditions (drought, flooding, nutrient deficiency, and herbivory). Invasive individuals grew larger and flowered later in benign conditions, and performed as well or better under most of the tested stress conditions than native individuals. The strongest evidence for a trade-off in tolerance was exhibited under drought conditions, but only among native populations. Chapter 3 employs a field common garden to compare phenotypes, drought response, and adaptation to environmental conditions in a more natural setting. This study incorporates a large dataset of occurrence locations to look at the different relationships that populations in the two ranges have to their bioclimatic environments. I found that invasive C. diffusa individuals were larger, matured later, and have lost adaptation to environmental conditions apparent in native populations. More plastic invasive genotypes may have expanded the climatic niche inhabited in the invaded range. Chapter 4 attempts to identify a genetic mechanism underlying these phenotypic changes by comparing gene expression between the two ranges under benign and drought conditions. Genes were identified whose expression either varied constitutively or responded to drought stress differently between ranges. Based on these data, invasive populations may have constitutively higher levels of energy production, while native populations have a stronger cellular drought defense. This dissertation presents ample evidence of evolution in the invaded range and suggests that plasticity and rapid evolution had a significant impact on the successful invasion of North America by C. diffusa.Science, Faculty of
Botany, Department of
Graduate
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Powell, Robert David. "Diffuse knapweed (Centaurea diffusa) : reproductive thresholds, population ecology and responses to the introduction of the buprestid beetle Sphenoptera jugoslavica." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29265.
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Diffuse knapweed (Centaurea diffusa), like other semelparous perennials, was found to have a minimum size requirement for flowering. This critical size conditions the plant's phenotypic response to variation in growth conditions. Experimentally crowded rosettes grew slowly, failed to reach the critical size and did not flower in the following season, whereas uncrowded rosettes grew rapidly, reached the critical size in a single year and flowered in the next. The proportion of plants that flowered and subsequently died in both field and experimental populations decreased with individual crowding. The effect of interference-related growth reduction was therefore to accentuate gaps in the population's spatial pattern. Interference-related mortality of seedlings and rosettes acted in the opposite direction. The three interference-related processes of recruitment, pre-reproductive and post-reproductive mortality determine the fine scale spatial pattern of the population, and its density. There is no theoretical basis for interpreting a shift toward regularity as evidence for interference.
A model, proposed to explain the apparent ubiquity of critical size-dependent switching to reproductive development in semelparous perennials, shows that this adaptation maximizes the intrinsic rate of increase of semelparous species subject to high juvenile mortality followed by low rosette mortality, seasonality, and extensive variability in rosette growth rates. The model suggests that biological control organisms might be chosen strategically to disrupt selection for the critical size.
Age-structured field populations exhibit considerable spatial variation in density. To determine whether that variation could account for a significant proportion of the variability in rosette growth rates under field conditions, the growth rates of individual plants were observed and regressed against a series of 'crowding indices'. Two methods of delimiting a sample of neighbours for this purpose were compared. 'Circular sampling' defines neighbours as plants within a specified radius of a focal plant; 'polygonal sampling' defines neighbours as plants that share a boundary when the ground is partitioned into Dirichlet polygons. A simulation study of the sampling characteristics of the two methods in relation to the degree of aggregation in the population showed that polygon samples are statistically preferable in aggregated populations, but the two methods performed about equally, accounting for approximately 25% of the variance in the growth rates of rosettes in the field.
The buprestid beetle Sphenoptera jugoslavica is the third insect established in Canada as a potential biological control for diffuse knapweed. The beetle population at the release site in British Columbia was monitored, and experiments were conducted to determine the beetle's effects on its host. S. jugoslavica reduces the survivorship of seedlings and rosettes, delays reproduction, and finally reduces seed output. Under favorable conditions the beetle can contribute to a significant reduction in knapweed population growth. Its effectiveness at the release site is limited by a phenological requirement for arrested plant growth during the oviposition period which leads to large fluctuations in the size of the beetle population, and only intermittent damage to the knapweed population.Land and Food Systems, Faculty of
Graduate
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Gupta, Anjali. "The Study of Diffuse Soft X-Ray Background." Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_dissertations/240.
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The cosmic X-ray background was discovered at the dawn of the X-ray astronomy: during the first successful rocket flight launched to study the X-ray emission from the Moon, the presence of a residual diffuse emission was also "serendipitously" revealed. In the intervening decades, observations with improving angular and spectral resolution have enhanced our understanding of the components that make up this background. Above 1 keV, the emission is highly isotropic on large angular scales, has extragalactic origin, and about ~80 percent has been resolved into discrete sources (Mushotzky et al. 2000, Hasinger et al. 1998). Our current interpretation of the diffuse X-ray emission below 1 keV uses a combination of 5 components, solar wind charge exchange, Local Bubble, Galactic halo, intergalactic gas, and unresolved point sources. Resolving the different components is made particularly difficult by the similar spectral emission of most components, X-ray lines of heavily ionized metals, which are poorly resolved by the energy resolution of CCD cameras onboard current X-ray satellites with typical observing times. The goal of this investigation is to assess the integral emission of the major components of the diffuse Soft X-Ray Background. In the first part of my project, I analyzed the shadow observations performed with XMM-Newton and Suzaku X-ray observatories. Shadow observations offer a tool to separate the fore ground component, due to the Local Bubble and, possibly, charge exchange within the solar system, from the background component, due primarily to the Galactic Halo and unidentified point sources. In the second part of my project, I studied the contribution of unresolved point sources and intergalactic medium to the diffuse Soft X-ray Background.
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Ben, Mokhtar Sonia. "Intergiciel Sémantique pour les Services de l'Informatique Diffuse." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2007. http://tel.archives-ouvertes.fr/tel-00469457.
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Voarino, Philippe. "Lumière diffuse et microsphères multicouches : calculs et réalisations." Phd thesis, Aix-Marseille 3, 2004. http://tel.archives-ouvertes.fr/tel-00083581.
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Nous avons développé des codes de calcul basés sur la théorie de Mie, pour prédire la réponse angulaire et spectrale de microsphères revêtues d'empilements multicouches concentriques, diélectriques ou métalliques. L'influence des paramètres est tout d'abord analysée avec précision : effet de taille, effet du revêtement, tolérance sur le rayon... L'analogie avec les fonctions optiques classiques (antireflet, miroir, filtres, séparateurs...) a retenu notre attention, et l'on montre qu'elle existe jusqu'à des rayons de l'ordre de 3 Μm, valeur critique en dessous de laquelle les résonances prédominent. Une étude colorimétrique a également permis de quantifier nombre d'effets colorés spécifiques à ces sphères multicouches.La deuxième partie de notre travail a consisté en la réalisation des micro-composants. Pour cela nous avons entièrement mis au point une technologie de pulvérisation par faisceau d'ions (IBS), pour fabriquer des couches minces optiques métalliques ou diélectriques. Pour revêtir les microsphères, nous les animons d'un mouvement aléatoire conféré par une membrane vibrante. Les résultats montrent que notre procédé fonctionne très correctement pour une fabrication en série, ouvrant ainsi la porte à des poudres optiques interférentielles. Ensuite le problème de la caractérisation est traité à l'aide d'un diffusomètre laser et d'un spectro-diffusomètre, pour tenter de mesurer une sphère isolée ou des collections de microsphères.
De façon générale, ce travail trouve des applications dans la couleur et cosmétique, la visualisation, la furtivité et les télécom, le biomédical...
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Zibetti, Stefano. "Diffuse stellar components in galaxies and galaxy clusters." Diss., lmu, 2004. http://nbn-resolving.de/urn:nbn:de:bvb:19-30331.
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Haran, Terence. "Short-Wave Infrared Diffuse Reflectance of Textile Materials." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/phy_astr_theses/5.
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This thesis analyzes the reflectance behavior of textiles in the short-wave infrared (SWIR) band (1 – 2 microns) in order to identify/design potential diagnostic tools that allow the remote detection of human presence in a scene. Analyzing the spectral response of fabrics in the SWIR band has gained significant interest in the remote sensing community since it provides a potential path to discriminate camouflaged clothing from backgrounds that appear similar to the object of interest in the visible band. Existing research, originating primarily from the textiles community, has thoroughly documented the behavior of clothing fabrics in the visible band. Other work has shown that the differences in spectral response in the SWIR band allows for discrimination of materials that otherwise have the same visible spectral response. This work expands on those efforts in order to quantify the reflectance behavior and to better understand the physical basis for that behavior.
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Hao, Biao. "Measuring diffuse x-ray reflectivity from rough interfaces." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=24010.
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This thesis studies the diffuse x-ray scattering from rough interfaces. We review the scaling hypothesis of the height difference correlation function of rough interfaces, and the relationship between the roughness and the specular reflectivity and diffuse scattering cross-section in the distorted wave Born approximation (DWBA). We study the properties of the position sensitive detector (PSD), particularly its dark counts and noise level. The conventional setup and off-plane scan setup are compared for their advantages and disadvantages. We use a polished silicon surface to exemplify the data processing. We find that the parameters which fit the detector scan data can fit all data from the specular reflectivity, the rocking scan and the offset scan very well. The polished silicon surface is well described by an exponential form of the height-height correlation function which satisfies the scaling hypothesis.
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Long, William F. (William Frank) 1971. "Optical tomography by time-resolved diffuse reflectance measurements." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37618.
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The understanding of the interaction of light with a scattering/absorbing medium provides a foundation needed for developing many applications in diagnostic medicine and industry. The objective of this research was to obtain quantitative depth-resolved information about absorbing constituents in a scattering medium.Initially, the project focussed on quantification in samples where scattering and absorber concentration were variable. Using time resolved reflectance measurements, a series of statistical descriptors of the photon time distributions were calculated. Stepwise multilinear regression was used to formulate linear models from optimal linear combinations of the descriptors. It was found that the scattering coefficient, absorption coefficient and apparent particle diameter could be estimated to within 9, 10 and 7% of their reference values respectively.
An array of radial reflectance measurements on layered scattering/absorbing samples was made to obtain information sensitive to sub-surface changes in absorption. As an initial approach to depth-resolved quantification, classical tomographic reconstruction techniques were used. However, due to the ambiguity of the reconstruction, extremely poor estimates of the sub-surface absorption resulted. Chemometric methods were then employed for enhanced quantification. By using stepwise multilinear regression with time-resolved data, the absorption coefficient in the top region of a sample could be estimated to within 2%. However, errors in the absorption coefficient estimations deep within a sample remained high.
Further improvements in sample quantification were made by linearizing the reconstruction problem. By using a priori information about sample composition in upper regions, subsequent calibrations for lower regions were directed. Estimations of the absorption coefficient deep within a sample with hierarchical locally weighted calibration were obtainable at greater than 50% accuracy. This represented a 20% improvement at all sample depths over stepwise multilinear regression.
Confocal illumination and detection optics was also used for discriminating highly scattered photons from light, which follows a geometric path through a sample. When confocal optics were used together with information from the rising edge of time distribution, little enhancement in quantification was observed in comparison to an integrated signal. This important finding demonstrates that the confocal optical detection should be considered when imaging in scattering/absorbing media.