Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Design cellule.
Thèses sur le sujet « Design cellule »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleures thèses pour votre recherche sur le sujet « Design cellule ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les thèses sur diverses disciplines et organisez correctement votre bibliographie.
1
Qiu, Kepeng. "Analysis and optimal design of lightweight sandwich structures and materials." Besançon, 2008. http://www.theses.fr/2008BESA2046.
Texte intégralRésumé :
La thèse concerne les performances de l’analyse et de l’optimisation de structures composites légères du type “solides cellulaires et sandwich”. Une étude spécifique est consacrée à l’optimisation topologique de solides cellulaires à périodicité. La méthode de super-élément est développée et appliquée à l’analyse statique et dynamique de plaques composites en considérant l’influence de la topologie et des dimensions de cellules périodiques constituant la structure. La méthode multi-phase d’homogénéisation 3D est appliquée pour calculer les propriétés élastiques équivalentes de structures nid d’abeille. Ensuite, une méthode inverse d’homogénéisation est appliquée pour obtenir une configuration de la microstructure. Elle concerne la maximisation de propriétés élastiques ainsi que de conductivités thermiques. L’optimisation topologique est mise en œuvre pour maximiser la rigidité globale des structures cellulaires comprenant les cellules carrées ou cylindriques à symétrie cyclique. Tous les éléments volumiques représentatifs (RVE – representative volume element) d’une structure cellulaire périodique sont modélisés en utilisant la méthode de super-élément (SE). La technique de liaison des variables d’optimisation est utilisée pour la périodicité dans les structures optimales. Les différentes configurations optimales RVE-SE étudiées permettent d’illustrer l’influence du paramètre d’échelle entre RVE et SE sur le processus d’optimisation. Des relations entre les dimensions d’une cellule et le nombre de cellules dans une plaque avec différentes conditions aux limites et leurs influences sur les solutions optimales en statique et en dynamique sont étudiées<br>The thesis deals with the performance analysis and the topology design of lightweight cellular solids and sandwich structures. Special emphasis is devoted to the topological optimization of periodic cellular solids based on the super-element method. The bending static and dynamic analysis and the core design of sandwich panels considering the size effect of cells is developed. The multi-step homogenization method is applied to calculate the effective elastic constants of multi-layered 3D honeycomb sandwich. The effective results are credible by comparison with other methods including classical formula, energy method and engineering empirical method. An integrated topology optimization procedure is developed for the global stiffness maximization of different cellular solids such as cyclic-symmetry square and cylinder structures. Each RVE (representative volume element) of periodic cellular solids is modeled by the SE (super-element) method. The technique of linking the design variables is adopted to ensure the periodicity of the optimal configuration over the whole structure after optimization. The various optimal configurations permit to illustrate the influence of size variation of RVE-SE on the optimal results. The computational efficiency is studied during the optimization process when the super-element method is adopted. A special study on the size effect is carried out for the bending static and dynamic analysis of the core design of sandwich panels. Special attention is devoted to the influence of size effect on the optimal results
2
HAJHOUJ, MOUAMD. "Programmation hors ligne : emulation des composants d'une cellule robotisee." Paris, ENSAM, 1988. http://www.theses.fr/1988ENAM0005.
Texte intégralRésumé :
On traite du cas d'une cellule robotisee comportant plusieurs chaines cinematiques. Le module d'execution gene la synchronisation et la communication entr les differentes taches. Le passage au robot reel montre que l'emulation de la commande elimine les erreurs dues a l'utilisation d'algorithmes generaux
3
Diallo, Cheikh-Dieylar. "Study and design of new multibeam antenna architectures in Ku and Ka bands for broadband satellite applications." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S151/document.
Texte intégralRésumé :
Les antennes multifaisceaux (AMFs) sont cruciales pour les applications de télécommunications par satellite modernes et futures, civiles et militaires. La partie basse du spectre électromagnétique est saturée alors que de larges bandes de fréquences sont disponibles dans la bande Ka, dans laquelle des missions à très-haut débit ont émergées au cours de la dernière décennie. La tendance consiste à réduire la taille des spots pour les couvertures multi-spots afin de diminuer le prix des satellites. Ainsi des antennes d’ouverture de plus en plus grande électriquement sont requises, induisant des ruptures technologiques majeures. Les lentilles de Luneburg insérées dans un guide d’ondes à plans parallèles (GOPP) deux plaques métalliques parallèles (PMPs) sont des solutions attractives pour illuminer les AMFs, puisqu’elles peuvent aboutir à des formateurs de faisceaux de bande et champ de visée larges, pertes et coûts faibles, et simples à concevoir, réaliser et intégrer. Les travaux de cette thèse portent sur le développement de nouvelles méthodes d’implémentation et sur la conception de AMFs à base de lentille de Luneburg. La réalisation de la lentille de Luneburg est connue pour être un défi technologique majeur. Un état de l’art des méthodes de réalisation est fourni. Ensuite, deux nouvelles méthodes sont proposées, ainsi qu’une méthode et des outils de conception. La première méthode de réalisation consiste en une matrice périodique et régulière de plots métalliques de taille inférieure à la longueur d’onde, et où la séparation du GOPP varie. La hauteur des plots et la séparation du GOPP contrôlent la valeur de l’indice de réfraction équivalente. L’antenne à 9 faisceaux tout métal conçue, fabriquée et mesurée, comporte 8314 plots et présente d’excellentes performances, notamment meilleures que sa version à séparation de plaques constante. La seconde méthode de réalisation consiste en une matrice périodique et régulière de trous circulaires de taille inférieure à la longueur d’onde réalisés sur un des deux revêtements cuivrés d’un substrat diélectrique plus une plaque métallique supérieure séparée du plan des trous par une couche d’air d’épaisseur fixe. L’antenne à 5 faisceaux conçue comporte 2696 trous et présente de très bonnes performances comparés à ces semblables dans la littérature<br>Multi-beam antennas (MBAs) are crucial to modern and future, civilian and military satellite telecommunications applications. The low part of the electromagnetic spectrum is congested, while wide band of frequencies are available in the Ka-band, in which broadband missions have emerged in the last decade. The trend is reducing the size of spots in multi-beam coverage to reduce the cost of satellites, hence more electrically large antennas are needed, with major technological breakthrough as a consequence. Luneburg lenses in parallel-plate waveguide (PPW) are attractive solutions to excite MBAs, since they could lead to wide band and field-of-view, low loss and cost, easy to design, manufacture and accommodate Beam Forming Networks. This PhD deals with the development of novel implementations and the design of broadband, low loss and wide field-of-view Luneburg lens based MBAs. The implementation of the Luneburg lens is known as a major technological challenge. A state-of-the art of the implementation techniques is presented. Then two novel implementations of Luneburg lens in PPW environment are proposed, like design method, process and tools. The first implementation consists of a periodic and regular array of subwavelength vertical metal posts, where the PPW spacing is variable. The post height and PPW spacing modulate the equivalent refractive index. The all-metal 9-beams antenna designed, manufactured and measured, has 8314 posts and shows excellent performances, better than the traditional constant PPW spacing version. The second implementation consists of periodic and regular array of subwavelength circular holes etched on the copper cladding of a dielectric substrate with an air gap between the holes plane and the PPW top plate. The radius of the holes control the equivalent index. The 5-beams antenna designed has 2696 holes and shows very good performances as compared to similar devices in literature
4
Bichon, Alexia. "Etude et détection operando, à l'aide d'une électrode de référence, des hétérogénéités de vieillissement liées au design des cellules lithium-ion." Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALY009.
Texte intégralRésumé :
L’essor des batteries lithium-ion pour de multiples applications, et notamment pour les véhicules électriques, a accéléré la recherche associée. Afin d’étendre leurs usages, l’amélioration des performances en termes de densité d’énergie, de sécurité et de régime de charge est un enjeu majeur pour la décennie en cours. Pour répondre à ces critères, une meilleure compréhension des mécanismes de dégradation et de leurs conditions d’apparition est nécessaire [1]. De plus, il existe plusieurs « designs » et formats de cellules « batteries », et plusieurs types de sollicitations. Ces différents designs impactent les contraintes locales et donc les modes de vieillissement des matériaux internes. Ainsi, l’objectif de cette thèse était de mieux comprendre l’apparition et le développement des hétérogénéités de dégradation au sein de cellules électrochimiques utilisant les mêmes matériaux mais avec des « designs » différents.Nous avons choisi pour cette thèse de travailler sur des cellules, composées de NMC622 à la positive et de graphite + 10 % SiOx à la négative, assemblées en plusieurs designs et, nous avons étudié leur vieillissement suivant différentes sollicitations. Dans un premier temps, l’étude a porté sur l’impact de la sollicitation sur les mécanismes de dégradation afin d’établir un protocole favorable au vieillissement. Pour cela des cellules de petit format en mono-couche d'électrodes, de 30 mAh, ont été fabriquées et instrumentées avec une électrode de référence qui a permis de suivre l’évolution des potentiels de chacune des électrodes [2]. Un intérêt particulier a été porté à l’étude du potentiel de l'électrode négative et du lithium plating, responsable en grande partie de la perte de lithium cyclable lors des charges rapides. Cette première partie du travail a permis de définir les protocoles de vieillissement adaptés pour l’étude menée sur les cellules multicouches.Des cellules de plus grande capacité, 500 mAh, chimiquement identiques aux précédentes, ont été réalisées au laboratoire selon deux designs différents : stacké et bobiné prismatique. Vieillies selon des protocoles identiques, ces cellules nous ont permis de comparer les deux designs et d’identifier, pour chacun, les causes majeures de dégradation selon les types de cyclage. Les cellules bobinées ont présenté des hétérogénéités de vieillissement plus importantes que les cellules stackées.Enfin, connaissant les principaux effets du vieillissement tels que : l’assèchement local de l’électrolyte, la décohésion de la matière active et l’obstruction des pores du séparateur, ces défauts ont été reproduits artificiellement lors de la fabrication des cellules afin de mieux comprendre leur impact respectif. Nous avons, dans cette troisième partie, cherché à étudier comment une dégradation locale se développait et impactait le vieillissement de la cellule complète. Cette étape du travail a permis d’aider à la compréhension de l’origine de certaines hétérogénéités.En parallèle de ce travail expérimental, une étude de l’état de l’art nous a permis d’identifier des pistes pour l’intégration des hétérogénéités à l’échelle des électrodes au sein de modèles multi-physiques intégrant le vieillissement à l’échelle de la cellule. Ce travail a permis de dégager un certain nombre de perspectives quant à l’amélioration des modèles multi-physiques et la prise en compte des hétérogénéités de contrainte et de vieillissement en fonction du design des cellules.[1] J. S. Edge et al., Phys. Chem. Chem. Phys., vol. 23, no. 14, pp. 8200–8221, 2021, doi: 10.1039/D1CP00359C.[2] O. Chaouachi, et al., Electrochimica Acta, vol. 366, p. 137428, Jan. 2021, doi: 10.1016/j.electacta.2020.137428<br>The rapid development of lithium-ion batteries for a wide range of applications, particularly electric vehicles, has accelerated the pace of related research. In order to extend their use, improved performance in terms of energy density, safety and charging rate is a major challenge for the current decade. To meet these criteria, a better understanding of degradation mechanisms and their onset conditions is required [1]. In addition, there are several designs and formats of battery cells, and several types of stress. These different designs have an impact on local stresses and therefore on the ageing modes of internal materials. Thus, the aim of this thesis was to better understand the appearance and development of degradation heterogeneities within electrochemical cells using the same materials but with different "designs".For this thesis, we chose to work on cells composed of NMC622 on the positive electrode and graphite + 10 % SiOx on the negative electrode, assembled in several designs, and we studied their ageing under different cycling conditions. Initially, the study focused on the impact of cycling conditions on degradation mechanisms, in order to establish a protocol favorable to ageing. To this end, small-format cells with a single layer of 30 mAh electrodes were manufactured and instrumented with a reference electrode, enabling the evolution of potentials on each electrode to be monitored [2]. Particular attention was paid to studying the potential of the negative electrode and lithium plating, which is largely responsible for the loss of cyclable lithium during fast charging. This first part of the work enabled us to define the ageing protocols suitable for the study carried out on multilayer cells.Cells with a larger capacity, 500 mAh, chemically identical to the previous ones, were produced in the laboratory using two different designs: stacked and prismatic wound. Aged according to identical protocols, these cells enabled us to compare the two designs and identify, for each, the major causes of degradation depending on the type of cycling. Wound cells showed greater ageing heterogeneity than stacked cells.Finally, knowing the main effects of ageing such as: local drying of the electrolyte, decohesion of the active material and clogging of the separator pores, these defects were artificially reproduced during cell manufacturing in order to better understand their respective impact. In this third part, we sought to study how local degradation developed and impacted the ageing of the entire cell. This stage of the work helped to understand the origin of certain heterogeneities.In parallel with this experimental work, a study of the state of the art has enabled us to identify avenues for the integration of electrode-scale heterogeneities within multi-physics models incorporating ageing at the cell scale. This work has opened up a number of prospects for improving multi-physics models and taking account of stress and ageing heterogeneities as a function of cell design.[1] J. S. Edge et al., Phys. Chem. Chem. Phys., vol. 23, no. 14, pp. 8200–8221, 2021, doi: 10.1039/D1CP00359C.[2] O. Chaouachi, et al., Electrochimica Acta, vol. 366, p. 137428, Jan. 2021, doi: 10.1016/j.electacta.2020.137428
5
Loricourt, Johan. "Réalisation de liaisons céramique-métal par brasage dans une cellule prototype d’électrolyse de la vapeur d’eau à haute température pour la production d’hydrogène." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20037.
Texte intégralRésumé :
L'électrolyse de la vapeur d'eau à haute température et sous pression avec des électrolytes à conduction protonique est un moyen envisagé pour produire massivement de l'hydrogène à un coût compétitif. Pour être fonctionnelle, une cellule d'électrolyse doit être hermétique vis-à-vis de l'extérieur et entre le compartiment anodique (O2 et H2O) et le compartiment cathodique (H2). Ainsi, la réalisation de liaisons céramique-métal est nécessaire, soit pour l'intégration de l'électrolyte (liaison perovskite-métal), soit pour l'intégration d'alimentations électriques (liaison alumine-métal). Compte-tenu des conditions de fonctionnement de la cellule (600°C, 50 bars, vapeur d'eau), seul un procédé de brasage est envisageable pour réaliser des jonctions résistantes mécaniquement et hermétiques. L'expertise des processus de corrosion sous vapeur d'eau a permis de définir la partie métallique et la brasure pour cette application et a montré que des alliages spécifiques étaient requis. L'étude de métallisation des céramiques par PVD pour permettre le mouillage de la brasure au moment du brasage a montré que la présence d'une barrière de diffusion était nécessaire, pour éviter la dissolution du dépôt lors du passage à l'état liquide de la brasure. Après une étude de mouillabilité à chaud de la brasure sélectionnée sur les céramiques métallisées et les substrats métalliques, les liaisons ont été optimisées en appliquant la méthodologie des plans d'expériences sur des éprouvettes normalisées. L'ensemble des résultats a ainsi conduit au développement de liaisons céramique-métal possédant de bonnes propriétés mécaniques (Rm = 60 MPa à 20°C) et hermétiques<br>Steam electrolysis at high temperature and under pressure with protonic conduction electrolyte is a way to produce hydrogen massively at low cost. To operate, an electrolysis cell must be hermetic especially between the anodic compartment (O2 and H2O) and the cathodic one (H2). Thus, ceramic to metal assemblies are needed, either to insert the electrolyte (perovskite-metal junction) or to realize power supply (alumina-metal junction).Considering the operating conditions (873°K, 725 PSI, steam), only a brazing process is possible to realize strong and hermetic junctions.The evaluation of corrosion process under steam pressure has enabled to select a metallic component and a brazing alloy for this application, and has shown that specific alloys are needed.The studies of ceramics metallization by PVD to assure the brazing alloy wetting throughout the brazing process have shown that a barrier diffusion was necessary to avoid the dissolution of coatings when the brazing alloy become liquid.After wetting experimentations of the chosen brazing alloy over the metalized ceramics and the metallic substrate, ceramic to metal assemblies have been optimized in applying the experimental design methodology on standard samples (ASTM).The whole results have enabled to develop hermetic ceramic to metal assemblies having good mechanical properties (Rm = 8700 PSI at 300°K)
6
Quinton, Cassandre. "Dérivés de s-tétrazine et de triphénylamine : du design aux applications." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2013. http://tel.archives-ouvertes.fr/tel-00957915.
Texte intégralRésumé :
Les travaux présentés dans ce mémoire de thèse portent sur la synthèse et l'étude des propriétés spectroscopiques et électrochimiques de systèmes donneur-accepteur conçus pour des applications variées telles que l'électrofluorochromisme, l'absorption à deux photons et le photovoltaïque. La s-tétrazine a été choisie comme accepteur pour sa forte affinité électronique, ses propriétés émissives remarquables et sa capacité à s'organiser via des interactions intermoléculaires de type --stacking. La triphénylamine a été sélectionnée comme donneur pour son faible potentiel d'ionisation, ses propriétés spectroscopiques (fortes absorption et émission) et la modulation facile de ses propriétés par changement de substituants. Sept dérivés de triphénylamine ont été synthétisés ainsi que dix-huit nouveaux composés multichromophoriques à base de tétrazine et de triphénylamine présentant cinq liens différents et des substituants variés. Ils ont été caractérisés par électrochimie et spectroscopie (stationnaire et résolue en temps). L'étude de la modulation de leurs propriétés photophysiques par le changement de l'état rédox a ensuite été réalisée. Dix composés présentant un lien permettant la conjugaison entre la triphénylamine et la tétrazine ont été synthétisés et caractérisés par électrochimie et spectroscopie. Compte-tenu de leurs propriétés, six d'entre eux ont été testés en absorption à deux photons et deux ont étés retenus pour être utilisés comme donneurs dans une cellule photovoltaïque organique. Par ailleurs, deux réactions ont été étudiées en détail pour expliquer la formation des produits obtenus, inattendus à un premier abord.
7
Da, Silva Joao Lucas. "Design and control of a multicell interleaved converter for a hybrid photovoltaic-wind generation system." Phd thesis, Toulouse, INPT, 2017. http://oatao.univ-toulouse.fr/19318/7/DASILVA_JoaoLucas.pdf.
Texte intégralRésumé :
The solution for the generating energy derived from non-polluting sources configures a worldwide problem, which is undetermined, complex, and gradual; and certainly, passes through the diversification of the energetic matrix. Diversification means not only having different sources converted into useful energy, like the electricity, but also decentralizing the energy generation in order to fit with higher adequacy the demand, which is decentralized too. Distributed Generation proposes this sort of development but in order to increase its penetration several technical barriers must be overpassed. One of them is related to the conversion systems, which must be more flexible, modular, efficient and compatible with the different energy sources, since they are very specific for a certain area. The present study drives its efforts towards this direction, i.e. having a system with several inputs for combining different renewable energy sources into a single and efficient power converter for the grid connection. It focuses on the design and control of an 11.7 kW hybrid renewable generation system, which contains two parallel circuits of photovoltaic panels and a wind turbine. A multicell converter divided in two stages accomplishes the convertion: Generation Side Converter (GSC) and Mains Side Converter (MSC). Two boost converters responsible for the photovoltaic generation and a rectifier and a third boost, for the wind constitue the GSC. It allows the conversion to the fixed output DC voltage, controlling individually and performing the maximum power point tracking in each input. On the other side, the single-phase 4- cell MSC accomplishes the connection to the grid through an LCL filter. This filter uses an Intercell Transformer (ICT) in the first inductor for reducing the individual ripple generated by the swicthing. The MSC controls the DC-link voltage and, by doing that, it allows the power flow from the generation elements to the network.
8
Hadj, Ahmed Asmaa. "Design of new electrochemical cells for studying enzymes by protein film electrochemistry." Electronic Thesis or Diss., Aix-Marseille, 2022. http://www.theses.fr/2022AIXM0100.
Texte intégralRésumé :
L’électrochimie directe des protéines (PFE) est une technique dans laquelle une enzyme est adsorbée à une électrode et son activité catalytique est mesurée sous forme d’un courant électrique, ce qui permet l’étude de la cinétique d’enzyme en fonction de différents paramètres expérimentaux. Cette technique nécessite un transport rapide du substrat vers l’électrode. Dans une étude précédente, notre équipe a proposé une nouvelle cellule électrochimique offrant un transport supérieur à l’électrode tournante, couramment utilisée dans les méthodes PFE. Dans cette thèse, nous avons exploré, à l’aide de CFD, l’effet des différents paramètres et proposé des formules semi-empiriques pour prédire les propriétés de transport dans la cellule. Puis, nous avons validé expérimentalement nos prédictions. En outre, nous avons construit un nouveau type de cellule avec des mélangeurs intégrés qui devraient permettre des changements rapides de concentrations<br>Protein Film Electrochemistry (PFE) is a technique in which an enzyme is adsorbed at an electrode and its catalytic turnover rate is measured as an electrical current which allows the investigation of enzyme’s kinetics as a function of different experimental parameters. However, this technique requires fast transport of the substrate towards the electrode. In a previous study, our team proposed a new design based on the wall-tube electrode that provides better transport than the rotating disc electrode, which is commonly used in PFE methods. In this thesis, we explored, using CFD, the effect of the various parameters of the design and proposed semi-empirical formulas to predict the mass transport coefficient and shear stress at the electrode. We used a 3D-printed cell to validate experimentally our predictions. Moreover, we designed and built a new type of wall-tube electrodes with integrated mixers that should allow faster changes of substrate and inhibitor’s concentrations
9
Moussy, Alice. "Caractérisation des premières étapes de différenciation des cellules hématopoïétiques à l'échelle de la cellule unique." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEP029/document.
Texte intégralRésumé :
Bien que largement étudiés, les mécanismes fondamentaux de prise de décision dans les processus de différenciation cellulaire restent mal compris. Les théories déterministes, souvent basées sur des études populationnelles, atteignent rapidement leur limite lorsqu’il s’agit d’expliquer les différences de choix individuels de cellules, pourtant exposées au même environnement. L’objectif de ma thèse est donc d’étudier les premières étapes de la différenciation des cellules hématopoïétiques à l’échelle de la cellule unique, par des analyses transcriptomiques, protéomiques et morphologiques. Ce travail a été effectué sur deux modèles de différenciation : les lymphocytes T régulateurs et les cellules CD34+ humaines issues de sang de cordon. Nous avons observé le comportement de ces cellules uniques après stimulation. Grâce à la combinaison de la microscopie en time lapse et des analyses moléculaires réalisées à l’échelle de la cellule individuelle, nous avons pu démontrer que le choix du devenir cellulaire n’était pas unique, programmé. La cellule passe d’abord par un état dit « multi-primed », métastable où elle exprime des gènes de plusieurs lignées différentes, puis elle passe par une phase dite « incertaine », instable où elle hésite entre deux phénotypes avant de se stabiliser dans un état fixe. Nos observations sont cohérentes avec une explication stochastique de la prise de décision. La différenciation serait donc un processus spontané, dynamique, fluctuant et non un processus prédéterminé. Les décisions du destin cellulaire sont prises séparément par les cellules individuelles<br>Despite intensively studies, the fundamental mechanisms of cell fate decision during cellular differentiation still remain unclear. The deterministic mechanisms, often based on studies of large cell populations, cannot explain the difference between individual cell fates choices placed in the same environment. The aim of my thesis work is to study the first steps of hematopoietic cell differentiation at the single cell level thanks to transcriptomic, proteomic and morphological analyses. Two differentiation models have been used: T regulatory lymphocytes and human cord blood-derived CD34+ cells. The behavior of individual cells following stimulation has been analyzed. Using time-lapse microscopy coupled to single cell molecular analyses, we could demonstrate that the cell fate choice is not a unique, programmed event. First, the cell reaches a metastable “multi-primed” state, which is characterized by a mixed lineage gene expression pattern. After transition through an “uncertain”, unstable state, characterized by fluctuations between two phenotypes, the cell reaches a stable state. Our observations are coherent with a stochastic model of cell fate decision. The differentiation is likely to be a spontaneous, dynamic, fluctuating and not a deterministic process. The cell fate decisions are taken by individual cells
10
Barnard, Damian Kelly. "Design and construction of modular genetic devices and the enzymatic hydrolysis of lignocellulosic biomass." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/7688.
Texte intégralRésumé :
The enzymatic deconstruction of lignocellulosic plant biomass is performed by specialist microbial species. It is a ubiquitous process within nature and central to the global recycling of carbon and energy. Lignocellulose is a complex heteropolymer, highly recalcitrant and resistant to hydrolysis due to the major polysaccharide cellulose existing as a crystalline lattice, intimately associated with a disordered sheath of hemicellulosic polysaccharides and lignin. In this thesis I aim to transfer the highly efficient cellulolytic mechanism of the bacterium Cellulomonas fimi, to that of a suitably amenable and genetically tractable expression host, in the hopes of better understanding the enzymatic hydrolysis of lignocellulose. Using tools and concepts from molecular biology and synthetic biology, I constructed a library of standardised genetic parts derived from C. fimi, each encoding a known enzymatic activity involved in the hydrolysis of cellulose, mannan or xylan; three of the major polysaccharides present in lignocellulose. Characterization assays were performed on individual parts to confirm enzymatic activity and compare efficiencies against a range of substrates. Results then informed the rational design and construction of parts into modular devices. The resultant genetic devices were introduced into the expression hosts Escherichia coli and Citrobacter freundii, and transformed strains were assayed for the ability to utilize various forms of xylan, mannan and cellulose as a sole carbon source. Results identified devices which when expressed by either host showed growth on the respective carbon sources. Notably, devices with improved activity against amorphous cellulose, crystalline cellulose, mannan and xylan were determined. Recombinant cellulase expressing strains of E. coli and C. freundii were shown capable of both deconstruction and utilization of pure cellulose paper as a sole carbon source. Moreover, this capacity was shown to be entirely unhindered when C. freundii strains were cultured in saline media. These findings show promise in developing C. freundii for bioprocessing of biomass in sea water, so as to reduce the use of fresh water resources and improve sustainability as well as process economics. Work presented in this thesis contributes towards understanding the complementarities and synergies of the enzymes responsible for lignocellulose hydrolysis. Moreover, the research emphasizes the merits of standardizing genetic parts used within metabolic engineering projects and how adopting such design principles can expedite the research process.
11
Slotta, Douglas J. "Structural Design Using Cellular Automata." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/33368.
Texte intégralRésumé :
Traditional parallel methods for structural design do not scale well. This thesis discusses
the application of massively scalable cellular automata (CA) techniques to structural design.
There are two sets of CA rules, one used to propagate stresses and strains, and one to
perform design analysis. These rules can be applied serially, periodically, or concurrently,
and Jacobi or Gauss-Seidel style updating can be done. These options are compared with
respect to convergence, speed, and stability.<br>Master of Science
12
Winkworth-Smith, Charles G. "Cellulose composite structures – by design." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/28823/.
Texte intégralRésumé :
The aim of the work presented in this thesis was to investigate different mechanical and chemical pre-treatments which can dramatically change the properties of native cellulose and add alternative routes to structure formation. Ball milled cellulose, which had a reduced crystallinity, degree of polymerisation and degradation temperature, was rehydrated in excess water resulting in recrystallisation. Fully amorphous samples recrystallised to the more thermodynamically stable type II polymorphic crystal structure. Flash differential scanning calorimetry (DSC), which allows thermal transitions to be scanned at much higher rates than conventional DSC, was able to register a glass transition temperature for amorphous cellulose. The next stage of the study focussed on the production of freeze dried galactomannan foams. Cellulose fibres provided reinforcement to the foams. The level of reinforcement was related to fibre content, size, crystallinity and surface roughness. Microfibrillated cellulose (MFC) provided the greatest reinforcement due to its much higher surface area and fibrillated structure. Extrusion was found to be a useful alternative to homogenisation for the production of MFC and to create foams using alternative processing to the freeze drying routes. A novel molten salt hydrate, LiCl/urea/water, was found to swell native cellulose and reduce its crystallinity. A weak gel-like structure was formed at ambient temperature. Micro DSC results showed that this structure was melted out at 60oC but the process was reversible indicating hydrophilic to hydrophobic conformational changes on the surface of the cellulose fibres, although these were likely to be dependent on the celluloses having a low degree of polymerisation. In these solvent conditions starch granules were eroded from the outside rather than being swollen as has been found for some ionic liquids and underwent total dissolution in LiCl/urea/water. Fenugreek and xyloglucan, which are both highly branched, were found to increase in viscosity in LiCl/urea/water relative to water, possibly due to the breakage of all intramolecular associations whereas the viscosity of konjac which is predominantly unbranched did not change. Locust bean gum (LBG) had a lower viscosity in LiCl/urea/water compared to water due to the disruption of aggregates. Confocal microscopy showed that fenugreek and LBG are able to bind to cellulose in water, however, the conformational change of fenugreek in these solvent conditions inhibited it from binding to cellulose in LiCl/urea/water whereas conformational change allowed xyloglucan to bind to cellulose in LiCl/urea/water whilst it was unable to bind in water. Konjac did not bind to cellulose in either solvent system. The pre-treatments shown in this work will enable the creation of novel cellulose composites.
13
Bajic, Mirko M. "Design of dynamic cellular manufacturing systems." Title page, abstract and contents only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phb165.pdf.
Texte intégralRésumé :
Bibliography: leaves 172-184. An analytical approach to the integrated problems of designing the dynamic cellular manufacturing systems layout concurrently with its material flow (handling) requirements, in such a manner that minimises the material handling within the system. The proposed strategy encourages the design of a dynamic layout to identify simultaneously the machine groups, economical machine distribution, and intracell and intercell layouts.
14
Mohebbi, Behzad Barjasteh. "UHF propagation and cellular system design." Thesis, University of Leeds, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305519.
Texte intégral
15
Leu, Yow-yuh. "Cellular manufacturing: applicability and system design." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39922.
Texte intégralRésumé :
As competition has intensified, many American manufacturers have sought alternatives to rejuvenate their production systems. Cellular manufacturing systems have received considerable interest from both academics and practitioners. This research examines three major issues in cellular manufacturing that have not been adequately addressed: applicability, structural design, and operational design.
Applicability, in this study, is concerned with discerning the circumstances in which cellular manufacturing is the system of choice. The methodology employed is simulation and two experimental studies are conducted. The objective of Experiment I, a 2 x 3 x 3 factorial design, is to investigate the role of setup time and move time on system performance and to gain insight into why and how one layout could outperform another. The results of Experiment I suggest that move time is a significant factor for job shops and that workload variation needs to be reduced if the performance of cellular manufacturing is to be improved. Experiment II evaluates the impact of setup time reduction and operational standardization on the performance of cellular manufacturing. The results of Experiment II suggest that cellular manufacturing is preferred if the following conditions exist: (1) well balanced workload, (2) standardized products, (3) standardized operations, and (4) setup times independent from processing times.<br>Ph. D.
16
Herr, Christiane Margerita. "From form generators to automated diagrams using cellular automata to support architectural design /." Thesis, Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B39848954.
Texte intégral
17
Ghafari, Bamdad. "Extendable design of a cellular network simulator." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq64079.pdf.
Texte intégral
18
Jones, David Huw. "Design and application of convergent cellular automata." Thesis, Durham University, 2009. http://etheses.dur.ac.uk/84/.
Texte intégralRésumé :
Systems made of many interacting elements may display unanticipated emergent properties. A system for which the desired properties are the same as those which emerge will be inherently robust. Currently available techniques for designing emergent properties are prohibitively costly for all but the simplest systems. The self-assembly of biological cells into tissues and ultimately organisms is an example of a natural dynamic distributed system of which the primary emergent behaviour is a fully operational being. The distributed process that co-ordinates this self-assembly is morphogenesis. By analysing morphogenesis with a cellular automata model we deduce a means by which this self-organisation might be achieved. This mechanism is then adapted to the design of self-organising patterns, reliable electronic systems and self-assembling systems. The limitations of the design algorithm are analysed, as is a means to overcome them. The cost of this algorithm is discussed and finally demonstrated with the design of a reliable arithmetic logic unit and a self-assembling, self-repairing and metamorphosising robot made of 12,000 cells.
19
Wu, Yue. "Computer-aided design of cellular manufacturing layout." Thesis, Durham University, 1999. http://etheses.dur.ac.uk/1464/.
Texte intégral
20
Egilmez, Gokhan. "Stochastic Cellular Manufacturing System Design and Control." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1354351909.
Texte intégral
21
Feng, Song. "Exploring design principles of cellular information processing." Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/79687/.
Texte intégralRésumé :
As a summary, this work attempts to explore and uncovered design principles of certain dynamics of cellular networks by combining evolution in silico with rule-based modelling approach. Biological systems exhibit complex dynamics, due to the complex interactions in the intra- and inter- cellular biochemical reaction networks. For instance, signalling networks are composed of many enzymes and scaffolding proteins which have combinatorial interactions. These complex systems often generate response dynamics that are essential for correct decision-makings in cells. Especially, these complex interactions are results of long term of evolutionary process. With such evolutionary complexity, systems biologists aim to decipher the structure and dynamics of signalling and regulatory networks underpinning cellular responses; synthetic biologists can use this insight to alter existing networks or engineer de novo ones. Both tasks will benefit from an understanding of which structural and dynamic features of networks can emerge from evolutionary processes, through which intermediary steps these arise, and whether they embody general design principles. As natural evolution at the level of network dynamics is difficult to study, in silico evolution of network models can provide important insights. However, current tools used for in silico evolution of network dynamics are limited to ad hoc computer simulations and models. In my PhD study, with collaborators I construct the BioJazz, an extendable, user-friendly tool for simulating the evolution of dynamic biochemical networks. Unlike previous tools for in silico evolution, BioJazz allows for evolution of cellular networks with theoretically unbounded complexity by combining rule-based modelling with an encoding of networks that is akin to a genome. BioJazz can be used to implement biologically realistic selective pressures, and allows exploration of the space of network architectures and dynamics that implement prescribed physiological functions. It is provided as an open-source tool to facilitate its further development and use. I use this tool to explore the possible biochemical designs for signalling networks displaying ultrasensitive and adaptive response dynamics. By running evolutionary simulations mimicking different biochemical scenarios, we find that enzyme sequestration emerges as a key biochemical mechanism for both dynamics. Detailed analysis of these evolved networks revealed that enzyme sequestration enables both ultrasensitive and adaptive response dynamics. I verified this proposition by designing a generic model of a signalling cycle, featuring two enzymes and a sequestering (scaffold) protein. This simple system is capable of displaying both ultrasensitive and adaptive response dynamics, even more interestingly modulating the system switching between two response dynamics through perturbing the scaffold protein. These results show that enzyme sequestration can be exploited by evolution so to generate diverse response dynamics in signalling networks. From evolutionary simulations towards ultrasensitivity, bistable dynamics emerged as an alternative solution. On one hand, inspired by such results I used the fitness function as an objective function combined with different constraints to design and optimise bistable signalling networks with completely new structure and mechanism. Studying designed bistable signalling network explicates how such bistable network can be experimentally implemented. On the other hand, from studying the evolved bistable networks allosteric enzymes catalysing futile cycles appear to be a new mechanism of bistability in signalling networks. Furthermore, one of the smallest bistable signalling motifs is derived. This motif is composed of one kinase protein with two distinct conformational states and one substrate subject to phosphorylation by the kinase and auto-dephosphorylation reactions. The sufficient and necessary condition on parameters, with which the signalling motif displays bistable response dynamics, is analytically defined. By expanding the systems with more kinases, unlimited multistability emerges with potentials of implementing complex logic gates and cell state transitions. Further exploring the discovered and natural signalling networks implies shared design patterns. Motivated by searching structural boundaries between monostationary and multistationary networks, I performed algorithmic searching of multistationary signalling networks intending to find the sufficient structural conditions for multistationarity in signalling networks.
22
BONIFAZI, MAURIZIO. "Analog circuits design for cellular neural network." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2008. http://hdl.handle.net/2108/705.
Texte intégralRésumé :
Il paradigma delle Reti Neurali Artificiali (ANN) consiste nell’applicazione del modello neurale “biologico” per la risoluzione di problemi che spesso sono troppo complessi per un’architettura di Von Neumann.
La letteratura offre differenti approcci per l’implementazione di ANN. Qualche implementazione è di tipo software, altre sono soluzioni circuitali come circuiti digitali full-custom o FPGA (Field Programmable Gate Array), come pure circuiti analogici, e il tipo di implementazione di certo dipende dal tempo di esecuzione adeguato al tipo di applicazione.
Questa tesi riguarda la progettazione di nuovi circuiti analogici adattati per le Reti Neurali. In particolare, saranno utilizzate le Reti Neurali Cellulari (CNN) proposte nel 1981 dal Prof. L.O.Chua (University of California – Berkeley). Il “Laboratorio di Circuiti” dell’Università di Roma “Tor Vergata” ha progettato e realizzato alcuni chip analogici dedicati a questo tipo di Reti Neurali. Questi chip appartengono alla famiglia “Digital Programmable CNN” (DPCNN) e presentano principalmente due caratteristiche: la programmabilità digitale dei pesi sinaptici come una particolare architettura orientata ad una struttura interconnessa (cioè connettendo tra loro più di questi chip è possibile realizzare reti di grande dimensione).
In questa tesi viene data una visione di insieme sulle ANN, sulle CNN e sulle Star-CNN: cosa sono, come funzionano ed a cosa servono. In perticolare verrà descritta la famiglia DP-CNN.
Questa tesi propone una nuova architettura chiamata TD-CNN (Time Division CNN), che sfrutta una particolare strategia mirata a ridurra l’area di occupazione su silicio di una cella elementare, per aumentare l’integrabilità della rete. Oltretutto la stessa strategia a divisione di tempo verrà applicata alle TD-Star CNN. In particolare questi circuiti sono le non-linerità digitalmente programmabili (cioè DPTA – Digital Programmable Transconductance Amplifier e DPTA – Digital Programmable Transconductance Comparator) e circuiti particolari per la multiplazione (DM-SH – Dynamic Mirror Sample and Hold e DM-MUX – Dynamic Mirror Multiplexer). Sono mostrate alcune simulazioni dei circuiti per permettere lo studio di queste nuove architetture, e la modifica delle dinamiche introdotte dalla strategia a divisione di tempo.<br>The Artificial Neural Network (ANN) paradigm consists of the application of biological “neural” models to the solution of particular problems that often are very hard to solve for the classical “Von Neumann” architectures.
Different are the approaches proposed in literature for the implementation of an ANN. Some of them are software implementations only while, others are circuital solutions as full custom digital circuits or programmed FPGAs (Field Programmable Gate Array) as well as analogue circuits and the typology of the implementation certainly depends on the length of the processing time that you believe adequate for the particular application.
This thesis is focused on the design of new analogue circuits well suited for Neural Network applications. In particular, the class of the Cellular Neural Networks (CNN), proposed in 1981 by Prof. L.O.Chua (University of California - Berkeley), will be exploited. In this area, the “Laboratorio Circuiti” at University of Rome “Tor Vergata” designed and manufactured several analogue chips devoted to this class of Neural Networks. These chips belong to the Digital Programmable CNN (DPCNN) chip family and present two main features: the digital programmability of the synaptic weights as well as a special architecture oriented to an interconnection structure (i.e. it is possible to carry out large network by connecting together more of these chips).
In this thesis work you will find an overview about the Artificial Neural Network, the Cellular Neural Network and the Star Cellular Neural Network: what they are, how they work and why they are useful. In particular, the DP-CNN chip family will be deeply described.
This thesis proposes the TD-CNN (Time Division CNN), a particular design strategy, devoted to reduce the silicon area occupation of the a elementary cell in order to improve the VLSI integrability of the network. Moreover, the same time-division strategy will be applied to TD-Star CNN. In particular, these circuits consist of the digitally programmable non-linearity circuits (i.e. the Digital Programmable Transconductance Amplifier - DPTA and Digital Programmable Transconductance Comparator – DTPC) and special circuit for to carry out the multiplexing feature (i.e. the Dynamic Mirror Sample and Hold – DM-SH and the Multiplexer – DM-MUX).
Several circuital simulations will be shown in order to study the behavior of this modified architecture and the modifications on the dynamics introduced by the time division strategy.
23
CORINTO, FERNANDO. "Cellular Nonlinear Networks: Analysis, Design and Applications." Doctoral thesis, Politecnico di Torino, 2005. http://hdl.handle.net/11583/2501297.
Texte intégral
24
Zheng, Zhihua, and 鄭智華. "Dynamic channel assignment for cellular mobile radio communication systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31246333.
Texte intégral
25
Craye, Étienne. "De la modélisation à l'implantation automatisée de la commande hiérarchisée de cellules de production flexibles dans l'industrie manufacturière." Lille 1, 1989. http://www.theses.fr/1989LIL10004.
Texte intégral
26
Hänggi, Martin. "Analysis, design, and optimization of cellular neural networks /." Zürich, 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13225.
Texte intégral
27
Coury, Sergio. "Quantitative models for the design of cellular networks." Thesis, Imperial College London, 1993. http://hdl.handle.net/10044/1/7947.
Texte intégral
28
Zhang, Changyang. "Energy Ecient Cellular System Design with QoS Assurance." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187441.
Texte intégralRésumé :
Results from the smart-phones' ubiquitous Internet access and diverse multimedia applications, there has been an explosion in mobile data communication, this incredible increase will necessitate continual high energy consumption and leads to more CO2 emissions. It is crucial to develop more energy-efficient systems because of the potential harmful effects to the environment caused by CO2 emissions. It is also significant for the cellular network operators, since the electricity bills are a considerable portion of their Operational Expenditure (OPEX). The power consumption at base stations accounts around 60-80% of the total power consumption in a cellular network [1, 2]. Potential energy savings can be expected by implementing BSs sleeping mode, according to the traffic demands and user activity factors. There are many performance trade-offs in optimizing BSs sleeping modes [3]. One of them is the trade-off between service delay and power consumption of cellular networks. In this thesis, the service delay is considered as a measure of Quality of Service (QoS) user experiences. Based on the conception of cell wilting and dynamic base stations switching, BS sleep switching algorithms are developed while the QoS of User Equipments (UEs) is guaranteed in the meantime. The switching algorithms are decentralized which means no central controller is needed. The BSs can make the switching decisions based on the feedback from UEs and its neighboring BSs. Furthermore, the implementation of the proposed algorithms is also comprehensively described at the protocol level. An urban micro BSs network is built and used as the simulation scenario. Simulations are done with the help of the rudimentary network emulator (RUNE), a network simulator tool developed by Ericsson in MATLAB environment. Simulation results show that up to 62% of power consumption can be saved by implementing the QoS guaranteed BS switching algorithms. Furthermore, comparisons show that the QoS guaranteed BS switching algorithms have higher performance in terms of power consumption savings and QoS to the transitional BS switching algorithms. Many factors inuence the performance of BS switching algorithms. The analysis of the performance is challenging because the required parameters for analysis are dynamically changing during the switching processes. In this thesis, we develop a rough analysis, which gives an insight into some key factors affecting the performance. It shows that high system traffic load results in high power consumption and poor system performance. Either a very small or very large cell radius also leads to high power consumption and poor system performance for different reasons. In addition, choosing different values of the switching threshold affects the system performance in different ways.
29
Perreault, David John. "Design and evaluation of cellular power converter architectures." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10452.
Texte intégralRésumé :
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.<br>Includes bibliographical references (p. 155-160).<br>by David John Perreault.<br>Ph.D.
30
Xie, Ruinan. "Design and Manufacturing of Variable Stiffness Cellular Architecture." Thesis, North Dakota State University, 2017. https://hdl.handle.net/10365/31739.
Texte intégralRésumé :
Cellular structures are highly evaluated due to their high material efficiency. Both theoretical and experimental studies have done on periodic cellular structures. However, the mechanical performance can be stochastically distributed in the cellular architecture. This thesis presents the design and manufacturing of variable stiffness cellular architecture to achieve optimized topology by changing the unit cell parameters. The author applies image analysis technique to extract and digitize the information from the performance distribution map. Two types of cellular cells are studied for their relationship of stiffness and relative density. The methods of voxelization for both cells are also given in this study. This proposed methodology is then implemented to design a customized mattress and compare with current existing mattress. With the study of the unit cells and voxelization technique, our designed mattress aligns body curve better which provides more recuperation of the body during sleep.
31
Wissmann, Kord J. "New design methods for sheet pile cellular structures." Diss., This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-07132007-143154/.
Texte intégral
32
趙家輝 and Ka-fai Chiu. "Structured development of cellular FMS." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31238324.
Texte intégral
33
Hartka, Thomas Ryan. "Cellular Automata for Structural Optimization on Recongfigurable Computers." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/33508.
Texte intégralRésumé :
Structural analysis and design optimization is important to a wide variety of disciplines. The current methods for these tasks require significant time and computing resources. Reconfigurable computers have shown the ability to speed up many applications, but are unable to handle efficiently the precision requirements for traditional analysis and optimization techniques. Cellular automata theory provides a method to model these problems in a format conducive to representation on a reconfigurable computer. The calculations do not need to be executed with high precision and can be performed in parallel. By implementing cellular automata simulations on a reconfigurable computer, structural analysis and design optimization can be performed significantly faster than conventional methods.<br>Master of Science
34
Mok, Pui-Wing. "Design and Applications of Split-Luciferase Systems in Vitro and in Cellulo." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/333354.
Texte intégralRésumé :
Split-protein reassembly methods allow for the detection of a variety of macromolecular interactions in vitro, in cellulo and in vivo. Spilt-protein reporters, such as split-firefly luciferase (Fluc), depend upon the conditional reassembly of the genetically fragmented enzyme. The two fragments of Fluc conditionally reassemble and regain activity when protein domains appended to the N-terminal and C-terminal Fluc fragments interact. Our laboratory has previously reported the use of the split-Fluc system in the detection of protein-protein, protein-nucleic acid, and protein-small molecule interactions. Herein, I describe further developments in the split-Fluc system as applied to the specific detection of DNA, DNA modifications, and small molecule kinase inhibitors both in vitro and in cellulo. We have previously developed one of the first direct methods to detect any double stranded DNA sequence by attaching DNA binding domains, specifically designed Cys₂-His₂ zinc finger domains, to split-Fluc fragments. We previously discovered that designed Cys₂-His₂ zinc fingers were not specific for targeting a variety of promoter sequences. In order to improve DNA detection, I have designed and tested split-Fluc sensors against several relevant DNA targets using both designed zinc fingers and transcription activator-like effectors (TALEs). The results demonstrate that TALEs allow for significantly higher specificity than zinc fingers and provide a significant improvement for designing sequence specific split-Fluc systems for a variety of applications such as the detection of DNA methylation. The methylation at cytosine-guanine (CpG) dinucleotides in DNA is associated with transcriptional repression in normal cells. Aberrant changes in the mCpG levels on the promoter regions of tumor suppressor genes have been linked to cancer. We have previously shown that a sequence-specific mCpG split-Fluc sensor can be designed by attaching one fragment of the split-Fluc to a zinc finger and another fragment to the methyl-binding domain (MBD) protein, which selectively binds mCpGs. In the long term we wanted to improve these sensors and focused upon understanding the details of MBD binding to mCpG sites. I have completed a complete alanine-scan of the MBD domain using our split-Fluc systems that allows for determining how each residue in MBD1 contributes to mCpG DNA binding. The results showed that numerous residues being necessary for mCpG recognition that have not been previously identified, especially residues that likely contribute to an essential hydrophobic core. These alanine scanning results along with the improvements in DNA recognition with TALEs will potentially allow for the design and selection of more selective mCpG sensors. In a further area related to DNA modifications, in this case DNA damage, we have developed split-Fluc sensors for detecting the post-translational modification on proteins, poly(ADP-ribosyl)ation utilizing PAR-binding zinc fingers of the protein APLF. I have designed and tested a variety of PAR binding sensors and also demonstrated the utility of these sensors for measuring PAR in mammalian cells upon induction of DNA damage. In a separate area, our laboratory has been interested in developing methods for understanding the selectivity of small molecule kinase inhibitors using split-Fluc methods. Protein kinases catalyze the transfer of the ɣ-phosphate group from ATP to an acceptor protein and are involved in almost all signal transduction events. The deregulation of protein kinases is associated with many diseases, particularly cancer, and there has been tremendous interest in developing kinase inhibitors for therapeutic use. One of the main challenges is the ability to understand inhibitor selectivity as the >500 protein kinases in human possess very similar structures especially at the ATP-binding site targeted by small molecules. Our laboratory has previously reported an in vitro three-hybrid screen for protein kinase inhibitors, where one split-Fluc fragment is attached to a protein kinase, and the other is attached to the peptide Fos. A chemical inducer of dimerization (CID), composed of a peptide Jun, which dimerizes with Fos, as well as the ATP-binding kinase ligand, induces the formation of a three-hybrid complex that reassembles the split-Fluc. Small molecule inhibitors can be identified by their ability to prevent the formation of the three-hybrid system, resulting in reduced luciferase activity. There are few direct methods to interrogate small molecule binding in mammalian cells. In order to interrogate inhibitors in cells, we have developed a cell-permeable CID by replacing the Fos/Jun interaction with the E. coli dihydrofolate reductase-trimethoprim interaction. I have demonstrated that this new split-Fluc based three-hybrid system can be used to profile kinase inhibitors in a variety of cell lines.
35
Engelbrecht, Sarah. "Design of meso-scale cellular structure for rapid manufacturing." Thesis, Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/33876.
Texte intégralRésumé :
Customized cellular material is a relatively new area made possible by advancements in rapid manufacturing technologies. Rapid manufacturing is ideal for the production of customized cellular structure, especially on the meso scale, due to the size and complexity of the design. The means to produce this type of structure now exist, but the processes to design the structure are not well developed. The manual design of customized cellular material is not realistic due to the large number of features. Currently there are few tools available that aid in the design of this type of material. In this thesis, an automated tool to design customized cellular structure is presented.
36
Cai, Qibin. "Optimization-based design tools for W-CDMA cellular networks." Ann Arbor, Mich. : ProQuest, 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:3218184.
Texte intégralRésumé :
Thesis (Ph.D. in Operations Research)--S.M.U.<br>Title from PDF title page (viewed May 23, 2007). Source: Dissertation Abstracts International, Volume: 67-05, Section: B, page: 2813. Adviser: Jeffery L. Kennington. Includes bibliographical references.
37
El, Sayed Mostafa. "Multiscale mechanics and structural design of periodic cellular materials." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97009.
Texte intégralRésumé :
A periodic cellular material, also known as lattice material, is a periodic, reticulated micro-truss structure made up of a large number of elements; it is generated by tessellating a unit cell, composed of a small number of elements, in an infinite periodicity. Lattice materials are used to expand the properties of the solid material from which they are constructed to ranges of properties that depend on the lattice cell topology, besides the relative density, . The development of lattice materials results in expanding the materials selection design space, thereby providing tailored materials for advanced engineering applications.Recent progress on this new family of materials has led to a classification which categorizes lattice materials into two groups, namely, bending dominated and stretching dominated. The former contains lattice materials that collapse by the local bending of their microscopic constituents, generating mechanical properties that are far from optimal. The latter includes lattice cell topologies that collapse by the stretching of their cell elements, giving a much higher stiffness and strength per unit mass. Despite this recent research advance in the understanding of the failure mechanics of lattice materials, important challenges need to be addressed. i) To date, the current approaches for modeling infinite periodic lattice structures are applicable to certain lattice topologies only. A robust, automated, analytical procedure to characterize the mechanical properties of a lattice material with an arbitrary microscopic topology is missing. ii) The strategy followed in literature to shape the cross-sections of slender cell elements into circular shapes, results in a local buckling failure of the lattice elements. To avoid this collapse, researchers have proposed to increase the cross-section size of the microscopic elements; this resistance increase, however, occurs at the expense of the material weight. iii) A stretching dominated lattice material offers mechanical properties that are remarkably better than a bending dominated material. Its structure consisting of fully triangulated topologies might yet contain several redundant members that bring about undesired extra weight as well as non-conformal and non-morphing structural behavior.The work reported in this thesis aims at improving the current multiscale mechanics models as well as the structural analysis tools for the design of lattice materials.<br>Les matériaux cellulaires périodiques, aussi connus sous le nom de matériaux réseaux, sont constitués d'un grand nombre d'éléments de micro-treillis réticulés qui sont assemblés de manière périodique ; ils sont construits en assemblant un grand nombre de cellules composées d'un petit nombre d'éléments pour former un pavé dont la périodicité peut être infinie. Les matériaux réseaux servent à modifier les propriétés des matériaux solides qui les constituent selon la topologie des cellules ou la densité relative, . Le développement des matériaux réseaux permet d'élargir la gamme de matériaux pouvant servir dans la conception d'applications avancées.Les progrès récents dans cette nouvelle famille de matériaux ont mené à leur regroupement dans deux catégories: les matériaux dominés par le fléchissement et ceux dominés par l'étirement. Les premiers contiennent des matériaux réseaux qui s'affaissent par le fléchissement localisé de leurs cellules, conduisant à des propriétés qui ne sont pas optimales. Les derniers contiennent une topologie de cellules qui s'affaissent par l'étirement de leurs éléments, produisant ainsi une plus grande résistance par unité de masse. Malgré les avancés récentes dans la compréhension du mécanisme d'affaiblissement des matériaux réseaux, certains défis importants demeurent. i) Les modèles existants de structures réseaux périodiques sont applicables à certaines topologies seulement. Une procédure robuste, automatisée et analytique pour caractériser les propriétés mécaniques des matériaux réseaux ayant une topologie microscopique arbitraire doit être développée. ii) La stratégie utilisée dans la littérature pour former la section transversale d'éléments de cellule minces en formes circulaires mène à un affaiblissement des éléments du treillis par gondolement. Pour éviter cet affaissement, les chercheurs ont proposé d'augmenter la taille de la section transversale des éléments microscopiques. Cependant, cette augmentation de la résistance se fait au détriment du poids du matériau. iii) Les matériaux réseaux qui sont dominés par l'étirement offrent des propriétés mécaniques très supérieures à celles des matériaux dominés par le fléchissement. Leur structure, constituée uniquement de topologies triangulaires, pourrait toutefois contenir plusieurs membres superflus qui ajoutent un poids indésirable et un comportement structurel qui ne se conforme pas aisément.Le travail décrit dans cette thèse a pour but d'améliorer les modèles mécaniques existants à plusieurs échelles ainsi que les outils d'analyse structurelle servant à la conception de matériaux réseaux.
38
王曉曦 and Xiaoxi Wang. "Design of virtual cellular manufacturing systems using genetic algorithms." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B42577305.
Texte intégral
39
Cheung, Hing Keung. "Modelling, design and implementation of a flexible cellular network." Thesis, King's College London (University of London), 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417009.
Texte intégral
40
Sarper, H{u00FC}seyin. "Cellular and functional production environments: design methodology and comparison." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/81025.
Texte intégralRésumé :
A hybrid methodology was developed to fairly compare functional and cellular production environments with respect to the production of machined parts which constitute the indivisible components of some final products. The methodology provides a means of designing each production environment at the lowest possible cost and then comparing the two environments with respect to cost and non-cost performance measures. The results show that the long-held belief that the cellular manufacturing or group technology method of production may be superior to that of the traditional functional or job shop layout may not be correct. A detailed comparison using four problem sets with different job and machine mixes failed to indicate a clear case in which the cellular environment performed better than the functional.
The methodology consists of two stages. Stage one has six hierarchical steps which systematically determine machine requirements and layout planning of each environment through mathematical modelling. External and internal operation constraints and inputs such as stochastic daily demand and operation times were considered. Stochastic programming was used in handling uncertain daily demand and operation times by specifying a desired minimum probability of meeting the demand for each job type in both environments. The MPSIII package was used in solving large mixed integer problems that resulted once nonlinear terms, due to the chance-constrained nature of the segments of the models, were linearized. Because of the large problem sizes, MPSIII input files had to be created using FORTRAN codes.
In stage two, the SIMAN simulation language was used to determine the feasibility of stage one decisions and to obtain other system information. In simulation, some approximations were made to implement stage one decisions. For example, jobs received an average processing time in each operation class area rather than the exact operation time of the specific machine type to which the jobs were assigned in stage one. The effect of material handling distances and the use of limited number of work-in-process carriers were considered. Although the methodology was mainly developed for the comparison of the two production environments, it is readily usable for individual design of either production environment.
In addition to the two main stages of development, this research also required the development of two other procedures: unitizing daily demands and the modifying the previously available job/cell grouping methods.<br>Ph. D.
41
Kumar, Guneet. "Design of anion exchange cellulose hydrogel for large proteins." Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06062008-163945/.
Texte intégral
42
Wang, Xiaoxi. "Design of virtual cellular manufacturing systems using genetic algorithms." Click to view the E-thesis via HKUTO, 2003. http://sunzi.lib.hku.hk/hkuto/record/B42577305.
Texte intégral
43
Niakan, Farzad. "Design and configuration of sustainable dynamic cellular manufacturing systems." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0123/document.
Texte intégralRésumé :
La révolution la plus récente dans l'industrie (révolution industrielle 4.0) nécessite une plus grande flexibilité, agilité et efficacité dans l'utilisation des équipements de production. Le système manufacturier cellulaire dynamique (DCMS) est l'un des meilleurs systèmes de production qui répondent à ces exigences. En outre, l'importance croissante du développement durable force les fabricants et les gestionnaires à prendre en compte les enjeux environnementaux et sociaux dans la conception et la configuration des systèmes de fabrication. Cette thèse porte sur la configuration durable des DCMS en proposant trois modèles mathématiques. Le plus grand challenge de cette étude est (i) de choisir des critères sociaux et environnementaux appropriés, (ii) de les intégrer dans des modèles mathématiques et (iii) d'étudier l'impact de ces critères sur des DCMS. Le premier modèle est bi-objectif afin de faire un compromis entre certains critères sociaux (offres d'emplois, risques de la machine, etc.) et économiques (divers coûts liés à la formation de cellules). Pour être plus proche de situations de la vie réelle, certains paramètres tels que la demande, les coûts liés aux machines et la capacité en temps des machines sont considérés comme incertains. Pour résoudre ce problème, une méthode d'optimisation robuste est appliquée pour faire face à cette incertitude. Dans le deuxième modèle, toutes les dimensions du développement durable sont prises en compte dans le modèle mathématique bi-objectif proposé. La première fonction objectif modélise des critères économiques (coûts) et la seconde des aspects environnementaux (déchets de production), tandis que certaines contraintes représentent des questions sociales (principalement le « Daily Noise » à cause de la complexité de calcul). En raison de la NP-difficulté du problème, une nouvelle approche novatrice appelée NSGA II-MOSA est proposée. Le troisième modèle proposé a trois fonctions objectif, une pour chaque type d’enjeux : environnemental, social et économique. Afin d'être proche de la vie réelle, certains paramètres du modèle sont exprimés en termes de valeur floue. Nous proposons une méthode possibiliste hybride pour faire face à l'incertitude et une approche floue interactive est considérée pour résoudre un modèle multi-objectif déterministe pour des solutions de compromis. Enfin, la dernière partie de la thèse étudie la possibilité d'appliquer les trois modèles proposés à l’industrie grâce à une méthode plus facile. Une approche d'optimisation-simulation innovante est introduite pour faire face à la configuration de DCMS : (i) La phase d'optimisation fonctionne comme méthode de fractionnement de scénarii pour réduire le nombre de configurations alternatives en se concentrant sur les niveaux stratégique et tactique. (ii) Ensuite, un outil de simulation détaille le niveau opérationnel en étudiant la performance de chaque alternative et l'interaction entre plusieurs composants de cellules<br>The most recent revolution in industry (Industrial Revolution 4.0) requires increased flexibility, agility and efficiency in the use of production equipment. Dynamic Cellular Manufacturing System (DCMS) is one of the best production systems to meet such requirements. In addition, the increasing importance of sustainable development forces manufacturers and managers to take account of the environmental and social issues in the design and configuration of manufacturing systems. This thesis focuses on the sustainable configuration of DCMS by proposing three mathematical models. The main challenge of this study is to (i) choose appropriate social and environmental criteria, (ii) integrate them in mathematical models, and (iii) study the impact of these criteria on DCMS. The first model is bi-objective in order to make a trade-off between some social (job opportunity, potential machine hazards, etc.) and economic (various costs related to cell formation) criteria. To get closer to real-life situations, some parameters such as demand, machine-related costs and time capacity of the machines are considered as uncertain. To solve this problem, a robust optimization method is applied to cope with this uncertainty. In the second model, all dimensions of sustainable development are taken into account in a new bi-objective mathematical model. The first objective function models economic criteria (costs) and the second one environmental aspects (production waste), while social issues (mainly Daily Noise Dosage because of computational complexity) are modeled as constraints. Due to the NP-hardness of the problem, a new innovative approach called NSGA II-MOSA is proposed. The last model has three objective functions, one for each dimension of the sustainable development: environmental, social and economic. In order to be close to real life, some parameters of the model are expressed in terms of fuzzy value. We propose a hybridized possibilistic method to deal with uncertainty and an interactive fuzzy approach is considered to solve an auxiliary crisp multi-objective model in order to find trade-off solutions. Finally, the last part of the thesis studies the possibility to apply the three proposed models to the industry thanks to an easier method. A novel optimization-simulation approach is introduced to deal with the configuration of DCMS: (i) the optimization phase operates as scenario fraction method in order to reduce the number of alternative configurations by focusing on strategic and tactical levels; (ii) next, a simulation tool investigates the operational level by studying the performance of each alternative and the interaction between several components of the cells
44
MARIOT, LUCA. "Cellular Automata, Boolean Functions and Combinatorial Designs." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2018. http://hdl.handle.net/10281/199011.
Texte intégralRésumé :
Lo scopo di questa tesi è studiaregli Automi Cellulari (AC) dalla prospettiva delle funzioni booleane e dei disegni combinatorici. Oltre all'intrinseco interesse teorico, questa ricerca è motivata da applicazioni alla crittografia, dato che sia le funzioni booleane che i disegni combinatorici sono utilizzati nella progettazione di generatori di numeri pseudocasuali (Pseudorandom Number Generators}, PRNG) e degli schemi di condivisione di segreti (Secret Sharing Schemes, SSS).
I contributi della tesi sono stati sviluppati lungo tre linee di ricerca, di seguito descritte.
La prima linea di ricerca riguarda l'utilizzo di algoritmi di ottimizzazione euristica per cercare funzioni booleane aventi buone proprietà crittografiche, da impiegare come regole locali nei PRNG basati su AC. La motivazione principale di questo studio è il miglioramento del generatore di Wolfram, che è stato dimostrato essere vulnerabile a due attacchi crittoanalitici, a causa delle cattive proprietà crittografiche della regola 30. In primo luogo, in questa linea di ricerca viene sviluppata una versione discreta di un Particle Swarm Optimizer (PSO), che esplora lo spazio delle tabelle di verità di funzioni booleane bilanciate aventi una buona combinazione di nonlinearità, ordine di resilienza e criterio di propagazione. In seguito, viene proposto un Algoritmo Genetico (Genetic Algorithm}, GA) basato su una rappresentazione differente delle funzioni booleane, in particolare il loro spettro di Walsh.
La seconda linea di ricerca si occupa delle funzioni booleane vettoriali generate dalle regole globali degli AC. Il primo contributo in questa linea di ricerca considera il periodo delle preimmagini di configurazioni spazialmente periodiche sotto l'azione di un AC suriettivo, un problema che è collegato al numero di partecipanti di un SSS basato sugli AC pubblicato in letteratura. Il secondo contributo consiste nell'analisi delle proprietà crittografiche delle regole globali degli AC, con particolare riguardo al loro grado algebrico, nonlinearità e uniformità differenziale. Viene in seguito adottato un approccio euristico basato sulla Programmazione Genetica (Genetic Programming, GP) per ottimizzare le \emph{S-box} definite da AC con una buona nonlinearità e uniformità differenziale. Infine, viene considerato l'ordine di resilienza} e introdotta una nuova proprietà crittografica per le S-box generate da AC, l'immunità all'asincronia.
La terza linea di ricerca riguarda i disegni combinatorici generati tramite AC. Più precisamente, viene considerato il caso dei Quadrati Latini Ortogonali} (Orthogonal Latin Squares, OLS), poiché sono equivalenti ai codici di autenticazione perfetti e agli schemi di condivisione dei segreti a soglia. Il primo contributo in questa linea di ricerca concerne la costruzione e il conteggio degli OLS generati da AC lineari, basandosi su risultati della teoria dei campi finiti. Il secondo contributo, d'altro canto, generalizza questa analisi a OLS generati da AC nonlineari, sia attraverso un metodo combinatorico per l'enumerazione esaustiva, sia tramite un approccio euristico basato su GA e GP.<br>The goal of this thesis is to investigate Cellular Automata (CA) from the perspective of Boolean functions and combinatorial designs. Besides the inherent theoretical interest, this research also bases its motivation in cryptography, since Boolean functions and combinatorial designs have several applications in the design of Pseudorandom Number Generators (PRNG) and Secret Sharing Schemes (SSS).
The contributions presented in this thesis are developed along three main research lines, organized as follows.
The first research line concerns the use of heuristic optimization algorithms for designing Boolean functions with good cryptographic properties, to be used as local rules in CA-based PRNG. The main motivation is to improve Wolfram's pseudorandom generator, which has been shown to be vulnerable to two cryptanalytic attacks due to the poor cryptographic properties of rule 30. In this research line, we first develop a discrete Particle Swarm Optimizer (PSO) which explores the space of truth tables of balanced Boolean functions having good nonlinearity, resiliency and propagation criteria. Next, we design a Genetic Algorithm (GA) which works on a different representation of Boolean functions, namely their Walsh spectrum.
The second research line deals with vectorial Boolean functions generated by CA global rules. The first contribution investigates the period of preimages of spatially periodic configurations under the action of surjective CA, a problem which is related to the maximum number of players in a CA-based SSS already published in the literature. The second contribution analyzes the cryptographic properties of CA global rules, focusing on their algebraic degree, nonlinearity and differential uniformity. We then adopt a heuristic approach based on Genetic Programming (GP) to evolve S-boxes defined by CA with nonlinearity and differential uniformity. As a last contribution in this research line, we focus on the resiliency criterion and introduce a new cryptographic property for CA-based S-boxes, namely asynchrony immunity.
The third research line deals with combinatorial designs generated by CA. We specifically focus on the case of Orthogonal Latin Squares (OLS), since they are equivalent to perfect authentication codes and threshold secret sharing schemes. To this end, our first contribution in this research line concerns the construction and the enumeration of OLS generated through linear CA, leveraging on results from the theory of finite fields. The second contribution, on the other hand, extends the investigation to OLS generated by nonlinear CA, using both a combinatorial approach for exhaustive enumeration and a heuristic approach based on GA and GP.
45
Shojaeifard, Arman. "Cross-layer design and optimization of heterogeneous cellular mobile networks." Thesis, King's College London (University of London), 2013. https://kclpure.kcl.ac.uk/portal/en/theses/crosslayer-design-and-optimization-of-heterogeneous-cellular-mobile-networks(dfe31556-d8f0-4fdc-a9e3-8f01fed258ed).html.
Texte intégralRésumé :
The rapid growth of wireless communication and access, in conjunction with increasing demand and sophistication of wireless applications, supplicate intelligent and reliable systems to support the exchange of large classes of traffic with rising quality of service (QoS) requirements. In addition, co-operation among cellular systems that incorporate different radio access technologies is notably important as the current third generation (3G) universal mobile telecommunication systems (UMTS) are expected to co-exist with the emerging fourth generation (4G) long term evolution (LTE) technologies for years to come. To these ends, radio resource management (RRM) techniques across different network layers, conjointly with spectrum sharing strategies, are vital in achieving desirable performance in heterogeneous networks. In this thesis, novel cross-layer design strategies, for jointly optimizing the physical (PHY)-layer and data link layer (DLL) parameters, are proposed in the contexts of code division multiple access (CDMA) and shared-spectrum heterogeneous orthogonal frequency division multiplexing (OFDM)/CDMA networks. These strategies facilitate dynamic radio resource allocation by exploiting the random variations of channel and network activity. Transmit power and QoS constraints are imposed on systems to maintain communication costs, effectiveness and quality. This thesis makes four main contributions. Firstly, in the proposed cross-layer techniques, based on automatic repeat request (ARQ) delay limits and prescribed maximum packet loss rates in the DLL, the optimum outer-loop power control (OLPC) SNR-targets and the corresponding adaptive spreading factors are derived in the PHY-layer, as functions of the number of active users in the cell. The optimality is, in this sense, maximization of cell effective throughput. Secondly, the performance of the proposed interference-based resource allocation schemes are evaluated over Nakagami-m frequency -flat and -selective fading channels. In particular, frequency-selective channels with maximum ratio combining (MRC) RAKE receiver are considered. Thirdly, I consider the uplink in multi-user cellular communication systems with single- and multi- service traffic scenarios, which are respectively modelled with one- and multi- dimensional discrete Markov chains. Finally, a dynamic cross-layer resource allocation algorithm in the context of shared-spectrum heterogeneous OFDM/CDMA networks is proposed. Opportunistic spectrum access (OSA) is employed to utilize the idle parts of the primary spectrum, effectively minimizing the interference levels, to maximize the total deliverable secondary throughput. Throughput performance of the optimized schemes and the achieved improvements, relative to the non-optimized and state-of-the-art schemes, are demonstrated with theoretical and simulation results for various settings of system parameters.
46
Ramanath, Sreenath. "Cell design and resource allocation for small cell networks." Phd thesis, Université d'Avignon, 2011. http://tel.archives-ouvertes.fr/tel-00745594.
Texte intégralRésumé :
An ever increasing demand for mobile broadband applications and services is leading to a massive network densification. The current cellular system architectures are both economically and ecologically limited to handle this. The concept of small-cell networks (SCNs) based on the idea of dense deployment of self-organizing; low-cost, low-power base station (BSs) is a promising alternative. Although SCNs have the potential to significantly increase the capacity and coverage of cellular networks while reducing their energy consumption, they pose many new challenges to the optimal system design. Due to small cell sizes, the mobile users cross over many cells during the course of their service resulting in frequent handovers. Also, due to proximity of BSs, users (especially those at cell edges) experience a higher degree of interference from neighboring BSs. If one has to derive advantages from SCNs, these alleviated effects have to be taken care either by compromising on some aspects of optimality (like dedicating extra resources) or by innovating smarter algorithms or by a combination of the two. The concept of umbrella cells is introduced to take care of frequent handovers. Here extra resources are dedicated to ensure that the calls are not dropped within an umbrella cell. To manage interference, one might have to ensure that the neighboring cells always operate in independent channels or design algorithms which work well in interference dominant scenarios or use the backhaul to incorporate BS cooperation techniques. Further, small cell BS are most often battery operated, which calls for efficient power utilization and energy conservation techniques. Also, when deployed in urban areas, some of the small cells can have larger concentration of users throughout the cell, for example, hot-spots, which call in for design of SCNs with dense users. Also, with portable BSs, one has the choice to install them on street infrastructure or within residential complexes. In such cases, cell design and resource allocation has to consider aspects like user density, distribution (indoor/outdoor), mobility, attenuation, etc. We present the thesis in two parts. In the first part we study the cell design aspects, while the second part deals with the resource allocation. While the focus is on SCNs, some of the results derived and the tools and techniques used are also applicable to conventional cellular systems.
47
Hunkeler, Stephan. "Topology optimisation in crashworthiness design via hybrid cellular automata for thin walled structures." Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8295.
Texte intégralRésumé :
Crashworthiness design is one of the most critical areas of automotive design. It is really demanding for the structure and can therefore have a large influence on the final design. It is also difficult to model accurately and costly to simulate which has an important impact on the design process. Most car companies have now stopped addressing crashworthiness design with trial and error approaches, in favour of more advanced automated structural optimisation methods. While most relevant applications so far use size or shape optimisation, the ultimate way to achieve significant mass reduction is to use topology optimisation. However, topology optimisation methods for crashworthiness design are still a work in progress. Due to the high non-linearity of crash simulations, well-established classic topology optimisation methods cannot be applied directly to crashworthiness design. Alternative methods have been and keep being developed such as the Equivalent Static Loads method, the Ground Structure Approach or the Hybrid Cellular Automata (HCA). This thesis introduces an adapted version of Hybrid Cellular Automata using thin-walled ground structures. It combines the advantages of computing a real crash simulation while producing as an output a thin walled based topology needing minimal post-processing effort to be translated into a realistic design. In this method, the topology optimisation domain is filled up with a ground structure of thin walls which constitutes the elementary cells of the HCA method. These macro-elements replace the solid mesh elements used in the classic HCA approach. The details and implementation of the method are presented and discussed. Different application examples are detailed, including defining reinforcement patterns within extruded beams. Enriched space fillings patterns are studied and industrial application examples are presented. Eventually, recommendations for further studies and applications of the method are given.
48
Li, Zhuo 1982. "Deposition of model viruses on cellulose." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116088.
Texte intégralRésumé :
A bioactive paper is a paper that can detect, capture and deactivate water and airborne pathogens. In this project, we presented a model "bioactive paper" made by attaching T4 bacteriophages to a cellulose substrate. T4 bacteriophages can be genetically engineered to possess copies of cellulose-binding modules (CBM) on their capsids. This allows them to bind specifically onto cellulose surfaces. Our model surface is a thin film of regenerated cellulose made by spin coating a glass or quartz substrate with a cellulose triacetate and subsequently hydrolyzing the surface back to cellulose. We successfully demonstrated the attachment of the CBM-T4 bacteriophages onto cellulose substrates by the phage viability test. The deposition kinetics were measured using an impinging jet apparatus combined with an evanescent wave light scattering (EWLS) system. We first tested the apparatus by using amidine latex particles deposited on the cellulose at different flow rates and found them to be in a good agreement with the constant potential double-layer model. The adhesion experiments were also performed in an impinging jet apparatus in which the CBM-T4 bacteriophages and the unassembled protein complexes from a suspension of 4.08 x 10 8 PFU/mL were allowed to diffuse to the cellulose surface, The competitive diffusion kinetics were again studied by the EWLS technique. For CBM-T4, the blocking time was found to be around 58 minutes and the maximum surface number density of phages was 5.9 x 1010 per m 2.<br>Key phrases: bioactive paper, cellulose film, cellulose binding module, bacteriophage T4, evanescent wave light scattering, unassembled protein complex, diffusion kinetics
49
Azari, Amin. "Energy Efficient Machine-Type Communications over Cellular Networks : A Battery Lifetime-Aware Cellular Network Design Framework." Licentiate thesis, KTH, Kommunikationssystem, CoS, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194416.
Texte intégralRésumé :
Internet of Things (IoT) refers to the interconnection of uniquely identifiable smart devices which enables them to participate more actively in everyday life. Among large-scale applications, machine-type communications (MTC) supported by cellular networks will be one of the most important enablers for the success of IoT. The existing cellular infrastructure has been optimized for serving a small number of long-lived human-oriented communications (HoC) sessions, originated from smartphones whose batteries are charged in a daily basis. As a consequence, serving a massive number of non-rechargeable machine-type devices demanding a long battery lifetime is a big challenge for cellular networks. The present work is devoted to energy consumption modeling, battery lifetime analysis, and lifetime-aware network design for massive MTC services over cellular networks. At first, we present a realistic model for energy consumption of machine devices in cellular connectivity, which is employed subsequently in deriving the key performance indicator, i.e. network battery lifetime. Then, we develop an efficient mathematical foundation and algorithmic framework for lifetime-aware clustering design for serving a massive number of machine devices. Also, by extending the developed framework to non-clustered MTC, lifetime-aware uplink scheduling and power control solutions are derived. Finally, by investigating the delay, energy consumption, spectral efficiency, and battery lifetime tradeoffs in serving coexistence of HoC and MTC traffic, we explore the ways in which energy saving for the access network and quality of service for HoC traffic can be traded to prolong battery lifetime for machine devices. The numerical and simulation results show that the proposed solutions can provide substantial network lifetime improvement and network maintenance cost reduction in comparison with the existing approaches.<br><p>QC 20161103</p>
50
Chae, Jung Kyu. "Plateforme de spécification pour le développement de bibliothèques de cellules et d'IPs." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066140/document.
Texte intégralRésumé :
Une plateforme de conception est une solution totale qui permet à une équipe de conception de développer un système sur puce. Une telle plateforme se compose d'un ensemble de bibliothèques et de circuits réutilisables (IPs), d'outils de CAO et de kits de conception en conformité avec les flots de conception et les méthodologies supportés. Les spécifications de ce type de plateforme offrent un large éventail d'informations, depuis des paramètres de technologie, jusqu'aux informations sur les outils. En outre, les développeurs de bibliothèque/IP ont des difficultés à obtenir les données nécessaires à partir ces spécifications en raison de leur informalité et complexité. Dans cette thèse, nous proposons des méthodologies, des flots et des outils pour formaliser les spécifications d'une plateforme de conception et les traiter. Cette description proposée vise à être utilisée comme une référence pour générer et valider les bibliothèques et les IPs. Nous proposons un langage de spécification basé sur XML (nommé LDSpecX). De plus, nous présentons une méthode basée sur des références pour créer une spécification fiable en LDSpecX et des mots-clés basés sur des tâches pour en extraire les données efficacement. A l'aide des solutions proposées, nous développons une plateforme de spécification. Nous développons une bibliothèque de cellules standard en utilisant cette plateforme de spécification. Nous montrons ainsi que notre approche permet de créer une spécification complète et cohérente avec une réduction considérable du temps. Cette proposition comble également l'écart entre les spécifications et le système automatique existant pour le développement rapide de bibliothèques/IPs<br>A design platform (DP) is a total solution to build a System-On-Chip (SOC). DP consists of a set of libraries/IPs, CAD tools and design kits in conformity with the supported design flows and methodologies. The DP specifications provide a wide range of information from technology parameters like Process-Voltage-Temperature (PVT) corners to CAD tools’ information for library/IP development. However, the library/IP developers have difficulties in obtaining the desired data from the existing specifications due to their informality and complexity. In this thesis, we propose methodologies, flows and tools to formalize the DP specifications for their unification and to deal with it. The proposed description is targeting to be used as a reference to generate and validate libraries (standard cells, I/O, memory) as well as complex IPs (PLL, Serdes, etc.). First, we build a suitable data model to represent all required information for library/IP development and then propose a specification language named Library Development Specification based on XML (LDSpecX). Furthermore, we introduce a reference-based method to create a reliable specification in LDSpecX and task-based keywords to efficiently extract data from it. On the basis of the proposed solutions, we develop a specification platform. Experimentally, we develop a standard cell library from the specification creation to library validation by using the specification platform. We show that our approach enables to create a complete and consistent specification with a considerable reduction in time. It also bridges the gap between the specification and current automatic system for rapid library/IP development