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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

Error control with binary cyclic codes

Grymel, Martin-Thomas January 2013 (has links)
Error-control codes provide a mechanism to increase the reliability of digital data being processed, transmitted, or stored under noisy conditions. Cyclic codes constitute an important class of error-control code, offering powerful error detection and correction capabilities. They can easily be generated and verified in hardware, which makes them particularly well suited to the practical use as error detecting codes.A cyclic code is based on a generator polynomial which determines its properties including the specific error detection strength. The optimal choice of polynomial depends on many factors that may be influenced by the underlying application. It is therefore advantageous to employ programmable cyclic code hardware that allows a flexible choice of polynomial to be applied to different requirements. A novel method is presented in this thesis to realise programmable cyclic code circuits that are fast, energy-efficient and minimise implementation resources.It can be shown that the correction of a single-bit error on the basis of a cyclic code is equivalent to the solution of an instance of the discrete logarithm problem. A new approach is proposed for computing discrete logarithms; this leads to a generic deterministic algorithm for analysed group orders that equal Mersenne numbers with an exponent of a power of two. The algorithm exhibits a worst-case runtime in the order of the square root of the group order and constant space requirements.This thesis establishes new relationships for finite fields that are represented as the polynomial ring over the binary field modulo a primitive polynomial. With a subset of these properties, a novel approach is developed for the solution of the discrete logarithm in the multiplicative groups of these fields. This leads to a deterministic algorithm for small group orders that has linear space and linearithmic time requirements in the degree of defining polynomial, enabling an efficient correction of single-bit errors based on the corresponding cyclic codes.
412

Etude des équilibres chimiques dans le contexte d'accrétion et de différenciation des planètes telluriques / Chemical equilibria during the accretion and differentiation of the terrestrial planets

Fontaine, Asmaa 23 May 2014 (has links)
Les abondances en éléments sidérophiles du manteau terrestre indiquent une ségrégation du noyau dans un océan magmatique profond. Il est néanmoins difficile de contraindre les conditions d’oxydation prévalant lors de l’accrétion planétaire, en se basant sur les traceurs géochimiques, en raison du nombre important de paramètres qui affectent leurs partages entre métal et silicate. D’autre part, l’état d’oxydation des planètes peut évoluer au cours de l’accrétion. Par conséquent, la nature des matériaux accrétés lors de la formation des planètes reste incertaine. Afin d’apporter de nouveaux éléments de réponses à cette problématique, nous avons modélisé les équilibres chimiques ayant lieu dans la Terre primitive. Ces équilibres peuvent évoluer (i) en augmentant les conditions de pression et de température de la ségrégation du noyau lors de la croissance de la planète, (ii) en raison de la cristallisation de l’océan magmatique et (iii) à travers l’accrétion de matériaux hétérogènes de compositions et états redox différents. Nous avons exploré le rôle potentiel de l’érosion collisionnelle dans le contexte de l’accrétion de la Terre à partir de chondrites à enstatite. Pour cela, nous avons déterminé expérimentalement les compositions chimiques des liquides pseudo-eutectiques en fonction de la pression jusqu’à 25 GPa. Nous avons montré que ces premiers liquides sont très enrichis en SiO2 (jusqu’à 75 wt% SiO2) et en éléments alcalins (Na et K). Par conséquent, l’érosion collisionnelle de proto-croutes de planétésimaux formés de chondrites EH peut de manière efficace augmenter le rapport final Mg/Si du manteau terrestre et réduire ses concentrations en éléments alcalins volatils. Ce mécanisme peut donc concilier les différences compositionnelles entre la Terre et les chondrites à enstatite. Nous avons également déterminé expérimentalement le partage du soufre entre métal riche en fer et silicate. La concentration en soufre du manteau terrestre peut être expliquée par un équilibre entre manteau et noyau dans un océan magmatique profond. L’hypothèse de l’ajout de soufre dans un vernis tardif (Rose-Weston et al., 2009) n’est pas à exclure, mais il n’est pas indispensable pour atteindre la concentration en soufre du manteau. Ces résultats sont en accord avec les compositions isotopiques non chondritiques du soufre dans le manteau (Labidi et al., 2013). Le partage des éléments légers (S, Si, O) entre manteau et noyau a été modélisé à hautes pressions et températures en prenant compte de leurs interactions chimiques mutuelles et celles avec le carbone. En considérant 2 wt% S et jusqu’à 1.2 wt% C (comme il est suggéré par les études cosmochimiques), nous trouvons une solubilité de l’O comprise entre 1 et 2.4 wt%. Cette insertion de l’O dans le noyau n’est pas suffisante pour permettre à la Terre d’être à la fois accrétée de matériaux météoritiques oxydés et de posséder un noyau métallique d’une masse équivalente au tiers de la planète ainsi que 8 wt% FeO dans le manteau. Des conditions relativement réduites lors de la ségrégation du noyau sont également requises pour augmenter le taux de Si dans le noyau et expliquer le rapport Mg/Si super-chondritique de la Terre silicatée (Allègre et al., 1995; O’Neill et al. 1998). Ainsi, la Terre s’est plus probablement accrétée à partir de matériaux réduits comme les chondrites à enstatites, conduisant à un noyau constitué de 2 wt% S, 0 à 1.2 wt% C, 1 wt% O et 5.5 à 7 wt% Si. Nous avons également exploré le comportement du Fe lors de la cristallisation de la pérovskite magnésienne (le minéral le plus abondant du manteau terrestre) et son rôle sur l’état redox du manteau terrestre lors du refroidissement de l’océan magmatique. Nous avons montré que sa cristallisation induit une diminution du FeO dans le manteau solide, lors d’un équilibre avec un alliage de fer liquide à une fO2 de IW-2 en raison du caractère incompatible du Fe dans la pérovskite. (...) / Abundances of siderophile elements in the mantle indicate that the Earth’s core segregated in a deep magma ocean. Yet, it is unfortunately difficult to constrain the oxidation conditions prevailing during planetary accretion based on geochemical tracers due to the number of parameters playing a role in metalsilicate partitioning. In addition, the oxidation state of terrestrial planets can evolve during accretion. The nature of the accreted material during the formation of the terrestrial planets remains then still uncertain. Our strategy to improve our knowledge in this domain is to model the chemical equilibria taking place in the primitive Earth. The equilibria can evolve (i) as P-T conditions of core-mantle segregation increase with the size of the planet, (ii) due to crystallization of the magma ocean and (iii) with accretion of heterogeneous material of different composition and oxidation state. We explored the potential role of collisional erosion in the context of Earth’s accretion from Enstatite Chondrites. For this, we refined experimentally the chemical composition of pseudo-eutectic melts as a function of pressure up to 25 GPa. We show that the first melts are highly enriched in SiO2 (up to 75 wt% SiO2) and alkali elements (Na and K). Therefore, collisional erosion of proto-crusts on EH-planetesimals can efficiently increase their final Mg/Si ratio and decrease their alkali elements budget. It can help to reconcile compositional differences between bulk silicate Earth and Enstatite Chondrites. We performed new experiments on metal-silicate partitioning of sulphur. We show that the present-day sulphur concentration of the Earth’s mantle can be explained by core-mantle equilibration in a deep magma ocean. S-addition in a late veneer (Rose-Weston et al., 2009) cannot be excluded; however, it is not required in order to reach the S-mantel abundance. Our results are consistent with the non-chondritic S-isotopic nature of the mantle (Labidi et al., 2013). We modeled the core-mantle partitioning of the light elements (S, Si, O) at high pressures and temperatures, by taking into account of their mutual chemical interactions and that with C. With 2 wt% S in the core and a C concentration ranging 0 to 1.2 wt% (as evidenced with cosmochemical studies), we found the O solubility from 1 to 2.4 wt%. This O incorporation to the core is insufficient to both allow an Earth accretion from an oxidized meteoritic material and result in a planet composed of a core with a mass equivalent to the third of its mass and a mantle with 8 wt% FeO content. Reduced conditions during coremantle segregation are also required to enhance the Si content in the core, possibly up to 5 wt% Si, to explain the super chondritic Mg/Si of the bulk silicated Earth (Allègre et al., 1995; O’Neill et al. 1998). Altogether, we find that the Earth was most likely accreted from a reduced material, such as enstatite chondrites, leading to a core composed of 2 wt% S, 0 to 1.1 wt% C, 1 wt% O and 5.5 to 7 wt% Si. We investigated the role of Mg-perovskite (the most abundant mineral of the mantle) crystallization on the oxidation state of Earth’s mantle during cooling of the magma ocean. We show that its crystallization induces a decrease of FeO content of the solid mantle as Fe is incompatible in perovskite, when it is in equilibrium with a liquid Fe-alloy at an fO2 of IW-2. At these conditions, the Fe3+ insertion is also low and constant (Fe3+/ Fetot of 21 ±4 %). Hence, the Mg-Pv crystallization cannot be responsible for a substantial increase of the Earth’s mantle oxygen fugacity during core segregation. (...)
413

Développement de nouvelles explorations tissulaires et cellulaires des pathologies nasales obstructives / Local consequences of sinonasal diseases on tissular and cellular morphology

Papon, Jean-François 05 November 2010 (has links)
L’obstruction nasale chronique (ONC) est un symptôme banal qui révèle de nombreuses pathologies rhinologiques ostéo-cartilagineuses et/ou muqueuses. Les explorations de l’ONC aident à la démarche diagnostique et permettent d’évaluer le retentissement de l’ONC sur la muqueuse nasale.Afin de répondre aux problèmes que je rencontre dans ma pratique clinique en rhinologie, j’ai orienté mes travaux de recherche vers le développement de nouveaux outils d’exploration des pathologies nasales obstructives :1. A l’échelle tissulaire, dans le cadre des rhinites chroniques, en particulier le dysfonctionnement nasal neurovégétatif qui restait un diagnostic d’élimination. J’ai montré que la compliance nasale, mesurée par rhinométrie acoustique, est perturbée dans les deux causes les plus fréquentes de rhinite chronique, d’une part, et est utile au diagnostic de dysfonctionnement nasal neurovégétatif, d’autre part.2. A l’échelle cellulaire, en m’intéressant à la cellule ciliée de l’épithélium respiratoire. J’ai étudié les avantages et les limites de l’étude ciliaire par microscopie électronique à transmission pour le diagnostic de dyskinésie ciliaire primitive. A l’aide de la vidéomicroscopie numérique à haute vitesse, j’ai développé des paramètres objectifs permettant de caractériser précisément le battement ciliaire. J’ai montré que ces paramètres étaient utiles pour le diagnostic de dyskinésie ciliaire primitive, pour étudier les cils respiratoires au cours de l’amaurose congénitale de Leber ou pour étudier le rôle de la protéine BUG22 dans le battement ciliaire de la paramécie. / Chronic nasal obstruction (CNO) is a common symptom and corresponds to diseases affecting bones, cartilages and/or mucosa of the nose. Objective monitoring of nasal patency is useful for identifying the etiology of CNO and for evaluating its effects on the mucosa.My research is guided by the numerous challenges encountered through my clinical practice of rhinology. I have developed new objective tools for exploring obstructive nasal diseases:1. At tissue level, I focused on chronic rhinitis, especially the neurovegetative nasal dysfunction which remained a diagnosis of exclusion so far. Using acoustic rhinometry, I have shown that the nasal compliance was abnormal in the two most common causes of chronic rhinitis and was a useful measure for the diagnosis of neurovegetative nasal dysfunction.2. At cell level, I focused on the ciliated cell of the respiratory epithelium. I studied the advantages and limits of transmission electron microscopy analysis of cilia for the diagnosis of primary ciliary dyskinesia. Using digital high-speed videomicroscopy, I have established objective parameters that precisely characterize ciliary beating. I have shown that these parameters were useful for diagnosing primary ciliary dyskinesia, for studying respiratory cilia of patients affected by Leber congenital amaurosis or for studying the role of BUG22 protein in ciliary beating of paramecia.
414

Návrh a měření parametrů akustických difúzních prvků / Design and Measurement of Parameters of Acoustic Diffusors

Burda, Jan January 2018 (has links)
This work focuses on the issue of acoustic diffusers. The introductory chapter describes the necessary theory of the sound distribution through enclosed space. Acoustic fields are also described. A description of the different diffusion element types and theirs design methods follows. It focuses mainly on design, which uses pseudo-random mathematical sequences. The aim of the work is to produce several types of acoustic diffusors and to verify their diffusion properties by means of measurements. The work uses the AFMG Reflex to simulate the diffusion properties of the proposed elements. Further, the thesis contains a description of the diffusion properties measurement process by the boundary plane method and the process of evaluating the measured data using the Matlab program.
415

C*-algebras from actions of congruence monoids

Bruce, Chris 20 April 2020 (has links)
We initiate the study of a new class of semigroup C*-algebras arising from number-theoretic considerations; namely, we generalize the construction of Cuntz, Deninger, and Laca by considering the left regular C*-algebras of ax+b-semigroups from actions of congruence monoids on rings of algebraic integers in number fields. Our motivation for considering actions of congruence monoids comes from class field theory and work on Bost–Connes type systems. We give two presentations and a groupoid model for these algebras, and establish a faithfulness criterion for their representations. We then explicitly compute the primitive ideal space, give a semigroup crossed product description of the boundary quotient, and prove that the construction is functorial in the appropriate sense. These C*-algebras carry canonical time evolutions, so that our construction also produces a new class of C*-dynamical systems. We classify the KMS (equilibrium) states for this canonical time evolution, and show that there are several phase transitions whose complexity depends on properties of a generalized ideal class group. We compute the type of all high temperature KMS states, and consider several related C*-dynamical systems. / Graduate
416

Nkanelo wa swin'wana swa swixevo swa ndhavuko wa Vatsonga

Ngomani, Makhosani Joseph 09 1900 (has links)
MA (Xitsonga) / Ehansi ka Senthara ya M. E. R. Mathivha ya Tindzimi ta Afrika, Vutshila ni Ndhavuko / See the attached abstract below
417

Blicke auf das Grauen. German Concentration Camps – Ein Film als Quelle

Ebbrecht-Hartmann, Tobias 15 August 2019 (has links)
No description available.
418

An ontological history of ecclesial union

Fredsti, Sean Paul 08 1900 (has links)
A critical survey of early Church history, the works of the Church Fathers and several councils of the Church reveals a consistent call for unity. Heresies, politic intrigue and struggles for governance have aggravated attempts to remain in the union. The insistence on unity and the persistence of the Church to unify reveals an ontological reality. While our knowledge of the Church can be given in epistemological terms, looking at the Church to discover its essence, what it means to be church, opens a different way of encountering the Church and, eventually, understanding the nature of the Church to be one. The transformations in the early Church as it spread to new cultures, the impact on the Church at the founding of “New Rome” by the Emperor Constantine, the changes brought about when Constantinople fell to the Ottomans in 1453 and the resulting birth of the Renaissance in the West with the beginning of the autocephaly Church in Russia and subsequent reunions, are especially rich in manifestations of unification among dissidence. This paper will focus on these particular moments. The concept of looking at the essence of the Church exposes us to an understanding of what the Church is as a universal presence. Stating that the Church has no physical dimension, that it is a unique congregation abiding solely by an actual historic document or defined only by written doctrines does not show us its full essence. Likewise, seeing the Church as defined by how it differs from another, exists in objection to another church or how it avoids affiliation with others, reveals a body that does not have a unifying essence and is lifeless. Looking closer at its essence as it is revealed over time, shows us a living Church that has repeatedly manifested unification as its particularly unique identity. This paper is a reflective look of the Church through the ages which presents to us a look into the essence of the Church. Primary and secondary sources are critically examined with an emphasis on ontological manifestations. The moments in history that are presented in this paper are especially revealing of the unifying nature of the Church in various settings. This paper has limitations though. While the deliberate historic selections may give extraneous interpretations, it is intended to reveal previously under-estimated treasures, and this topic will require being given greater context in any expanded study. / Christian Spirituality, Church History and Missiology / D. Th. (Church History)
419

Microenvironnement et angiogénèse : implications dans la stratégie onco-chirurgicale des métastases hépatiques synchrones des cancers colorectaux / Microenvironment and angiogenesis : impact on onco-surgical management of synchronous colorectal liver metastases.

Lim, Chetana 12 June 2017 (has links)
Lors du diagnostic de cancer colorectal, près d’un quart des patients ont des métastases hépatiques dites synchrones. Lorsque la tumeur primitive est asymptomatique, la stratégie chirurgicale (chirurgie première de la tumeur primitive versus chirurgie première des métastases hépatiques) reste débattue. Les recommandations actuelles ne reposent que sur des accords d’experts qui elles-mêmes sont basées sur des études cliniques rétrospectives. L’étude du microenvironnement tumoral a pris ces dernières années une place majeure dans la recherche sur le cancer. Elle a permis de changer de paradigme avec une nouvelle conception du processus métastatique : une tumeur primitive peut agir sur le microenvironnement du futur site métastatique pour créer une "niche pré-métastatique". Cette niche pré-métastatique permettrait secondairement la croissance des cellules tumorales via une angiogénèse tumorale et la formation de métastases. Par une triple approche à la fois fondamentale, translationnelle et clinique, nous avons obtenu des données qui suggèrent qu’une chirurgie première de la tumeur colique ou rectale permet de moduler l’angiogénèse au sein du microenvironnement hépatique. Cette stratégie chirurgicale permettrait également d’améliorer le pronostic oncologique des malades et l’efficacité des anti-angiogéniques. / At the time of the diagnosis of colorectal cancer, nearly 25% of patients have synchronous liver metastases. When this tumor is asymptomatic, the question of surgical strategy (primary tumor first versus liver-first strategy) remains debated. Current recommendations are based on agreements of experts which are by themselves based on retrospective clinical studies. The study of the tumor microenvironment has taken in recent years a major place in the field of cancer research. It leads to new paradigm with a new conception of the metastatic process. It may be possible that the microenvironment of the metastatic sites can be modulated by the primary tumor to promote the formation of the pre-“metastatic niche”. This leads to promote the growth of cancer cells and increase the metastatic potential of primary tumor. By a multidisciplinary research including fundamental, translational and clinical approaches, we have shown that primary tumor first strategy could modulate tumor angiogenesis and liver metastatic process. It is associated with improved survival of patients and efficacy of the anti-angiogenic therapy.
420

En prestandajämförelse mellan objektorienterad design och dataorienterad design i C++, Java och Java Project Valhalla / A performance comparison between object-oriented design and data-oriented design in C++, Java, and Java Project Valhalla

Isacsson, Andreas, Renström, Christopher January 2023 (has links)
Datorspel behöver utnyttja hårdvara effektivt för att kunna vara tillgänglig på så många system som möjligt med varierande kapacitet. En viktig del i detta är att optimera användandet av processorns cacheminnen. Programmerare kan följa en dataorienterad design för att implementera cacheeffektiv kod. Detta förutsätter att programmeraren har kontroll över hur data lagras i minnet, vilket är svårt att uppnå i Java. Project Valhalla kan erbjuda funktioner för att åtgärda detta problem. I detta arbete jämfördes objektorienterad design med dataorienterad design i språken C++, Java och den pågående utvecklingen av Project Valhalla. En prototyp utvecklades och implementerades med olika kombinationer av dessa språk och designer. För varje implementation mättes prestanda och cacheeffektivitet. Resultatet visade att Java med Project Valhalla kan uppnå liknande prestanda som C++ vid dataorienterade implementationer. På grund av vissa begränsningar i Valhallas funktioner kommer det troligtvis inte bli ett praktiskt alternativ till lågnivåspråk inom en snar framtid. / Computer games need to utilize hardware efficiently in order to be available on as many systems as possible with varying capabilities. An important part of this is to optimize the use of the CPU’s cache. A programmer can follow a data-oriented design to implement cache-efficient code. This requires the programmer to have control over how data is stored in memory, which is difficult to achieve in Java. Project Valhalla may offer features to address this issue. In this thesis, object-oriented design was compared with data-oriented design in the languages C++, Java, and the ongoing development of Project Valhalla. A prototype was developed and implemented using different combinations of these languages and designs. For each implementation, performance and cache efficiency were measured. The result showed that Java with Project Valhalla can achieve similar performance to C++ in data-oriented implementations. Due to some limitations in Valhalla's features, it is unlikely that it will become a suitable alternative to low-level languages anytime soon.

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