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1
Martin, Valerie 1975 July 31. "Stepfamilies in Canada : numbers, characteristics, stability and childbearing." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115641.
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The following thesis examines stepfamilies in Canada within a socio-demographic framework, using the 2001 General Social Survey (GSS) on families, and is divided into three main sections. First, there is an extended literature review on family theory and the emergence of stepfamilies. This section provides the background for a discussion of why stepfamilies are still often perceived as problematic and, therefore, stigmatized; we also define different stepfamily forms. The question of how to measure stepfamilies is a major concern in this research. Indeed, depending on whether one takes a residential or an inter-residential perspective, the number of households involved in stepfamily life changes substantially. We first present a cross-sectional perspective by describing the stepfamilies examined at survey. The main focus here is to compare stepfamilies with intact and lone parent families in order to see the extent and nature of the differences between them. Our results suggest that stepfamilies do not differ as much as expected from intact families with regard to certain socioeconomic variables, such as income. The next stage involves an analysis of stepfamilies in a longitudinal perspective in order to better understand stepfamily dynamics. In doing so, we focus on stepfamily instability and the likelihood of having a common child, applying the method of event history analysis. In this longitudinal perspective, we find that stepfamilies face a high risk of experiencing a separation and that this risk increases substantially over time; we also find that stepfamily couples living in a common-law union have a higher risk of separation than those who are married. The arrival of a common child within a stepfamily appears to be determined mainly by the age of the mother and of existing children. The younger the mother and the younger the children, the more likely a stepfamily is to witness the arrival of a common child. The most compelling finding of this research lies in the differences observed in the outcomes of male and female respondents with regard to their stepfamily dynamics.
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Astels, Stephen. "Cantor sets and numbers with restricted partial quotients." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0017/NQ38215.pdf.
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Skwarchuk, Sheri-Lynn. "Children's acquisition of the English cardinal number words, a special case of vocabulary development." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0011/NQ30648.pdf.
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Muzychka, Yuri Stephan. "Analytical and experimental study of fluid friction and heat transfer in low Reynolds number flow heat exchangers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0015/NQ38258.pdf.
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Raule, Giacomo. "Studio delle criticità idrauliche del Canale di Bonifica Zonara Masere." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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Nella presente tesi è stato fatto un modello idrologico della Zonara Masere tramite l'utilizzo di SWMM. Svolta la simulazione dello stato attuale sono state individuate le criticità ed in seguito sono stati ipotizzati vari scenari di soluzione delle criticità. Infine trovata la soluzione ottimale si è effettuata una prima fase di progettazione delle opere di prevenzione ed una stima economica del costo della realizzazione del progetto. La tesi è stata svolta presso il Consorzio di Bonifica della Romagna nella sede di Rimini
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Walker, Richard Thomas. "A comparative investigation of the root number and canal anatomy of permanent teeth in a Southern Chinese population." Thesis, [Hong Kong : University of Hong Kong], 1987. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12335423.
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Ruhault, Sylvain. "Security analysis for pseudo-random number generators." Thesis, Paris, Ecole normale supérieure, 2015. http://www.theses.fr/2015ENSU0014/document.
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La génération d’aléa joue un rôle fondamental en cryptographie et en sécurité. Des nombres aléatoires sont nécessaires pour la production de clés cryptographiques ou de vecteurs d’initialisation et permettent également d’assurer que des protocoles d’échange de clé atteignent un niveau de sécurité satisfaisant. Dans la pratique, les bits aléatoires sont générés par un processus de génération de nombre dit pseudo-aléatoire, et dans ce cas, la sécurité finale du système dépend de manière cruciale de la qualité des bits produits par le générateur. Malgré cela, les générateurs utilisés en pratique ne disposent pas ou peu d’analyse de sécurité permettant aux utilisateurs de connaître exactement leur niveau de fiabilité. Nous fournissons dans cette thèse des modèles de sécurité pour cette analyse et nous proposons des constructions prouvées sûres et efficaces qui répondront à des besoins de sécurité forts. Nous proposons notamment une nouvelle notion de robustesse et nous étendons cette propriété afin d’adresser les attaques sur la mémoire et les attaques par canaux cachés. Sur le plan pratique, nous effectuons une analyse de sécurité des générateurs utilisés dans la pratique, fournis de manière native dans les systèmes d’exploitation (/dev/random sur Linux) et dans les librairies cryptographiques (OpenSSL ou Java SecureRandom) et nous montrons que ces générateurs contiennent des vulnérabilités potentielles<br>In cryptography, randomness plays an important role in multiple applications. It is required in fundamental tasks such as key generation and initialization vectors generation or in key exchange. The security of these cryptographic algorithms and protocols relies on a source of unbiased and uniform distributed random bits. Cryptography practitioners usually assume that parties have access to perfect randomness. However, quite often this assumption is not realizable in practice and random bits are generated by a Pseudo-Random Number Generator. When this is done, the security of the scheme depends of course in a crucial way on the quality of the (pseudo-)randomness generated. However, only few generators used in practice have been analyzed and therefore practitioners and end users cannot easily assess their real security level. We provide in this thesis security models for the assessment of pseudo-random number generators and we propose secure constructions. In particular, we propose a new definition of robustness and we extend it to capture memory attacks and side-channel attacks. On a practical side, we provide a security assessment of generators used in practice, embedded in system kernel (Linux /dev/random) and cryptographic libraries (OpenSSL and Java SecureRandom), and we prove that these generators contain potential vulnerabilities
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Heath, Kristy Marie. "Fluid Mud Formation in the Petitcodiac River, New Brunswick, Canada." Thesis, Boston College, 2009. http://hdl.handle.net/2345/922.
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Thesis advisor: Gail C. Kineke<br>Experiments were conducted in the Petitcodiac River in New Brunswick, Canada during June and August 2006 to study high-concentrations of suspended sediment in a turbulent system. This study will evaluate the conditions necessary for fluid mud formation by investigating 1) the suppression of turbulence at gradient Richardson numbers greater than 0.25; 2) a threshold condition for the amount of sediment a flow can maintain in a turbulent suspension; and 3) the influence of flocculation on vertical suspended-sediment transport. Direct measurements of salinity, temperature, current velocity, and suspended-sediment concentration were collected during accelerating and decelerating flows and when fluid mud formed. In June, current velocities were typically above 1 m s-1 and suspended-sediment concentrations were generally less than 10 g l -1. In August, current velocities were typically less than 1.5 m s-1, suspended-sediment concentrations were greater than 10 g l -1, and a high-concentration bottom layer formed rapidly during decelerating flood currents. Gradient Richardson numbers for concentrations greater than 10 g l -1 were generally greater than 0.25, suggesting strong density gradients have the ability to suppress turbulence. Results from the Petitcodiac suggest a carrying capacity threshold might exist, but is based on a critical gradient Richardson number between 1.0 and 2.0 rather than the previously accepted value of 0.25. Differences in the evolution of disaggregated grain size distributions for settling suspensions suggest flocculation plays an important role for fluid mud formation by enhancing settling of fine sediments<br>Thesis (MS) — Boston College, 2009<br>Submitted to: Boston College. Graduate School of Arts and Sciences<br>Discipline: Geology and Geophysics
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Souza, Edilson Guimarães de. "Análise experimental e numérica de convecção forçada em arranjo de obstáculos dentro de canal /." Ilha Solteira : [s.n.], 2010. http://hdl.handle.net/11449/88857.
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Resumo: O objetivo deste trabalho é a análise numérica e experimental de escoamento viscoso, incompressível, permanente, com transferência de calor, em um canal estreito contendo um arranjo de obstáculos retangulares. A análise experimental envolveu determinação de coeficiente de transferência de calor médio bem como o número de Nusselt médio e medidas de temperatura em esteira térmica para comparação com os resultados obtidos por simulação numérica. Para a análise numérica usamos o programa comercial de mecânica dos fluidos e transferência de calor computacional ICEPAK®. Verificamos que quanto mais adentro o obstáculo estiver no arranjo maior é a transferência de calor por convecção forçada. Determinamos coeficientes de transferência de calor médio e número de Nusselt médio (com incerteza entre 6 e 15%) e verificamos que o efeito da posição diminui à medida que a velocidade aumenta. Concluímos também que ambos os modelos de turbulência utilizados, k-ε padrão e k-ε RNG, foram incapazes de predizer o efeito da posição apropriadamente. Entretanto, o modelo k-ε RNG apresentou melhor comportamento, pois o seu uso resultou em soluções com valores de temperatura intermediários aos experimentais<br>Abstract: The purpose of this work is the study of the numerical and experimental viscous incompressible steady flow with heat transfer into a narrow channel containing a rectangular array of obstacles. The experimental approach involves determining the coefficient of heat transfer and temperature measurements in thermal wake for comparison with the results obtained in numerical simulations. For the numerical analysis we use the commercial program of fluid mechanics and heat transfer computational ICEPAK™. We confirmed that in the last lines of the array the biggest is the heat transfer by forced convection. We determined the average heat transfer coefficients (with uncertainty between 6 and 15%) and found that the effect of the position decreases as flow speed increases. We use in the simulations the k-ε turbulence model and the k-ε RNG turbulence model. We conclude that both turbulence models used were unable to predict the effect of the position properly. However, the k-ε RNG model showed better behavior. The numerical temperatures with this model were consistent to the experimental temperature<br>Orientador: João Batista Campos Silva<br>Coorientador: Amarildo Tabone Paschoalini<br>Coorientador: Marcio Antonio Bazani<br>Banca: Ricardo Alan Verdú Ramos<br>Banca: Marcio Higa<br>Mestre
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Man, Kin Foon. "Divine anger, divine holiness and the exclusion of Moses in Numbers and Deuteronomy." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31119.
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This dissertation investigates the exclusion of Moses from the Promised Land in Numbers and Deuteronomy. Why are there different reasons given for his exclusion in the two books? Can they be explained by the complex redactions of Deuteronomy? There are four different answers to the question of Moses’ exclusion. According to Deut 1-3, divine anger is directed at Moses because he is the leader of the first exodus generation on whom the wrath of God is visited. Moses is excluded because he should bear the same punishment as the first generation of Israelites who left Egypt. Another reason is given in Deut 4, a mixture of late layers in the Deuteronomistic History. Accordingly, Moses’ exclusion is compared to the destruction and scattering of the future generations of the Israelites who provoked God to anger. The “anger-punishment pattern” of Moses’ exclusion, which is a theme of divine anger in the Deuteronomistic History, is used to confess the sin of the Israelites. Thirdly, in the post-Priestly passages in Numbers and Deuteronomy, Moses is ordered to die because of the sin of failing to sanctify YHWH. The exclusion of Moses is a natural consequence of his death outside the Promised Land. Finally, Deut 31 and 34 imply that Moses has reached the limit of life span which was set by YHWH.
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Micheli, Gabrielle de. "Discrete Logarithm Cryptanalyses : Number Field Sieve and Lattice Tools for Side-Channel Attacks." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0104.
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Les cryptosystèmes dits à clé publique sont construits à l'aide de fonctions à sens unique qui assurent à la fois la sécurité et l'efficacité des cryptosystèmes. L'un des deux principaux candidats envisagés à l'origine pour construire de tels cryptosystèmes est l'exponentiation modulaire avec son opération inverse, le calcul de logarithmes discrets. Dans cette thèse, nous étudions la sécurité de protocoles qui utilisent des exponentiations modulaires où l'exposant est un secret du protocole. Afin d'évaluer la sécurité de tels protocoles, on peut d'une part estimer la difficulté de résoudre directement le problème du logarithme discret (DLP) dans les groupes considérés par les protocoles, ou examiner les vulnérabilités issues de l'implémentation des algorithmes d'exponentiation rapide. Une première façon d'estimer la sécurité des protocoles basés sur la difficulté du problème du logarithme discret est d'étudier directement la complexité des algorithmes qui résolvent ce dernier. Dans cette thèse, nous étudions la complexité asymptotique des algorithmes qui résolvent le DLP sur des corps finis « \F_{p^n} » précisément de la forme où les couplages prennent leurs valeurs. Nous proposons également une première implémentation et un calcul record d'un logarithme discret dans un corps fini de 521 bits en utilisant l'algorithme Tower Number Field Sieve, une variante de NFS dont la complexité asymptotique est meilleure. Cette variante n'avait jamais été implémentée auparavant en raison de la difficulté du crible algébrique dans des dimensions supérieures à deux. Enfin, la sécurité des protocoles déployés ne repose pas seulement sur la difficulté du problème mathématique sous-jacent, mais aussi sur l'implémentation des algorithmes considérés. De nombreux algorithmes d'exponentiation modulaire rapide se sont accumulés au fil des ans et certaines implémentations ont fait apparaître des vulnérabilités exploitables par des attaques par canaux auxiliaires. Un second aspect de cette thèse considère donc les principales méthodes pour reconstituer une clé secrète lorsque des informations partielles sont récupérées à partir d'un canal auxiliaire<br>Public-key cryptosystems are constructed using one-way functions which ensure both the security and the efficiency of the schemes. One of the two main candidates originally considered to construct public-key cryptosystems is modular exponentiation with its hard inverse operation, computing discrete logarithms. In this thesis, we study the security of protocols that make use of modular exponentiation where the exponent is a secret of the protocol. To assess the security of such protocols, one can either estimate the hardness of directly solving the discrete logarithm problem (DLP) in the groups considered by the protocols or look at implementation vulnerabilities from fast exponentiation algorithms. One way of estimating the security of protocols based on the hardness of the discrete logarithm problem is to directly study the complexity of the algorithms that solve the latter. In this thesis, we first study the asymptotic complexity of algorithms that solve DLP over finite fields “\F_{p^n}” precisely of the form where pairings take their values. These algorithms come from the index-calculus family from which the Number Field Sieve (NFS) is an example. This study allows us to draw conclusions on the security of pairing-based protocols. We also propose a first implementation of the variant Tower Number Field Sieve (TNFS) of NFS, which has better asymptotic complexity, along with a record computation of a discrete logarithm in a 521-bit finite field with TNFS. This variant had never been implemented before due to the difficulty of sieving in higher dimensions, i.e., dimensions greater than two. Finally, the security of deployed protocols not only relies on the hardness of the underlying mathematical problem but also on the implementation of the algorithms involved. Many fast modular exponentiation algorithms have piled up over the years and some implementations have brought vulnerabilities that are exploitable by side-channel attacks, in particular cache attacks. The second aspect of this thesis thus considers key recover methods when partial information is recovered from a side channel
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Silveira, Rodrigo Santiago. "Estudo experimental do efeito da razão de bloqueio em canal aerodinâmico sobre o Número de Strouhal e o fenômeno da biestabilidade no escoamento em cilindros." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/29399.
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Este trabalho apresenta um estudo experimental do efeito da razão de bloqueio em um canal aerodinâmico no Número de Strouhal e o fenômeno da biestabilidade. É estudado o escoamento turbulento sobre um cilindro e também sobre dois cilindros dispostos lado a lado, onde fez-se uso de cilindros de vários diâmetros a fim de variar a razão de bloqueio no canal. Dois tipos de espaçamento entre os tubos são estudados. A técnica experimental consiste na medição de flutuações de velocidades em um canal aerodinâmico utilizando a técnica de anemometria de fio quente. Os dados obtidos da medição no canal aerodinâmico são tratados com o uso de ferramentas estatísticas, espectrais e de ondaletas. Para um cilindro, os resultados confirmam o aumento do número de Strouhal com o aumento da razão de bloqueio, na faixa do número de Reynolds utilizada. Razões de bloqueio mais baixas podem acarretar diminuição do número de Strouhal, também em função do número de Reynolds. Os resultados confirmam a existência do fenômeno da biestabilidade no escoamento sobre dois cilindros dispostos lado a lado, assim como a influência da razão de bloqueio sobre o fenômeno, sendo mais predominante em um dos espaçamentos estudados. Para razões de bloqueio altas, o fenômeno da biestabilidade pode não ocorrer ou pouco ocorre. Para razões de bloqueio mais baixas podemos ter também a não ocorrência do fenômeno em função das dimensões dos tubos serem mais reduzidas, fazendo com que a captação do fenômeno também seja reduzida.<br>This paper presents an experimental study of the effect of blockage ratio in a aerodynamic channel on Strouhal number and the bistability phenomenon. It studied the turbulent flow around a single cylinder and also on two cylinders arranged side-by-side, where use has been made of cylinders of various diameters to vary the blockage ratio of the channel. Two types of pitch to diameter ratio are studied. The experimental technique consists of measuring velocity fluctuations in aerodynamic channel using the technique of hot-wire anemometry. The data obtained from measuring the aerodynamic channel are treated with the use of statistical tools, spectral and wavelet analysis. For a single cylinder, the results confirm the increase of the Strouhal number with increasing blockage ratio in the range of Reynolds number used. Lower blockage ratio can cause a decrease of the Strouhal number, also a function of Reynolds number. The results confirm the existence of the bistability phenomenon in the flow on two cylinders arranged side-by-side, as well as the influence of blockage ratio on the phenomenon, being more predominant in one of the row spacings. For higher blockage ratios, the bistability phenomenon may not occur or occurs shortly. For lower blockage ratio, due to the smaller dimensions of the tubes the phenomenon may not occur on the capture of the phenomenon is also reduced with the present experimental technique.
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Rifi, Mohamad Azzam. "Propagation d'ondes dans un canal plan en presence d'ecoulement." Poitiers, 1987. http://www.theses.fr/1987POIT2318.
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La propagation du mode fondamental est etudiee au moyen de l'equation de la pression (sans dispersion). Les autres situations sont abordees au moyen d'une methode de perturbation. Une approche variationnelle est egalement envisagee
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Souza, Edilson Guimarães de [UNESP]. "Análise experimental e numérica de convecção forçada em arranjo de obstáculos dentro de canal." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/88857.
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Made available in DSpace on 2014-06-11T19:23:38Z (GMT). No. of bitstreams: 0
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souza_eg_me_ilha.pdf: 959550 bytes, checksum: b4784dbcc883b1be2d0c6b7cce83f54b (MD5)<br>Fundação de Ensino Pesquisa e Extensão de Ilha Solteira (FEPISA)<br>O objetivo deste trabalho é a análise numérica e experimental de escoamento viscoso, incompressível, permanente, com transferência de calor, em um canal estreito contendo um arranjo de obstáculos retangulares. A análise experimental envolveu determinação de coeficiente de transferência de calor médio bem como o número de Nusselt médio e medidas de temperatura em esteira térmica para comparação com os resultados obtidos por simulação numérica. Para a análise numérica usamos o programa comercial de mecânica dos fluidos e transferência de calor computacional ICEPAK®. Verificamos que quanto mais adentro o obstáculo estiver no arranjo maior é a transferência de calor por convecção forçada. Determinamos coeficientes de transferência de calor médio e número de Nusselt médio (com incerteza entre 6 e 15%) e verificamos que o efeito da posição diminui à medida que a velocidade aumenta. Concluímos também que ambos os modelos de turbulência utilizados, k-ε padrão e k-ε RNG, foram incapazes de predizer o efeito da posição apropriadamente. Entretanto, o modelo k-ε RNG apresentou melhor comportamento, pois o seu uso resultou em soluções com valores de temperatura intermediários aos experimentais<br>The purpose of this work is the study of the numerical and experimental viscous incompressible steady flow with heat transfer into a narrow channel containing a rectangular array of obstacles. The experimental approach involves determining the coefficient of heat transfer and temperature measurements in thermal wake for comparison with the results obtained in numerical simulations. For the numerical analysis we use the commercial program of fluid mechanics and heat transfer computational ICEPAK™. We confirmed that in the last lines of the array the biggest is the heat transfer by forced convection. We determined the average heat transfer coefficients (with uncertainty between 6 and 15%) and found that the effect of the position decreases as flow speed increases. We use in the simulations the k-ε turbulence model and the k-ε RNG turbulence model. We conclude that both turbulence models used were unable to predict the effect of the position properly. However, the k-ε RNG model showed better behavior. The numerical temperatures with this model were consistent to the experimental temperature
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Reuter, William H. Howard Richard M. Hobson Garth V. Buning Pieter G. "Flowfield computations over the space shuttle Orbiter with a proposed canard at a Mach number of 5.8 and 50 degrees angle of attack /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School; Available from the National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA258058.
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Thesis (Degree of Aeronautical and Astronautical Engineer) Naval Postgraduate School, June 1993.<br>Thesis advisors, Richard M. Howard, Garth V. Hobson and Pieter G. Buning. AD-A258 058. Includes bibliographical references. Also available online.
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Reuter, William H. IV. "Flowfield computations over the space shuttle Orbiter with a proposed canard at a Mach number of 5.8 and 50 degrees angle of attack." Thesis, Monterey, California. Naval Postgraduate School, 1993. http://hdl.handle.net/10945/39837.
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Clavel, Milène. "Etude de l'intégration de transistors à canal en graphène épitaxié par une technologie compatible CMOS." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00721765.
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Le graphène est un plan unique d'atomes de carbone formant une structure en nid d'abeilles. Dans le cas idéal, le graphène possède des propriétés physiques étonnantes résultant de sa structure électronique en " cône de Dirac ". En particulier, la mobilité électronique dans le graphène est exceptionnelle ce qui ouvre des perspectives pour les transistors futurs. Dans cette thèse notre objectif est de tester les propriétés et les performances de transistors réalisés sur graphène à l'aide d'une technologie compatible CMOS. Depuis 2004, il est connu qu'on peut obtenir ce matériau bidimensionnel à partir de la graphitisation du carbure de silicium (SiC). C'est cette technique qui a été utilisée ici. Parmi les résultats obtenus, nous présenterons en particulier une méthode innovante pour déterminer le nombre de couches de graphène. Nous détaillerons la technologie d'intégration mise au point, avec la réalisation de transistors à canal court et étroit. Nous montrerons les caractéristiques obtenues. La mobilité électronique mesurée est à l'état de l'art international. Nous analyserons également le rôle du diélectrique de grille sur la qualité des performances.
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Xu, Bingrui. "Hydrodynamique de fluides élancés à bas nombres de Reynolds." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS074/document.
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Le sujet de cette thèse est l'hydrodynamique de corps minces (feuilles) et élancés (filamenteux) de fluide visqueux immergés dans un second fluide ayant une viscosité différente. Nous nous concentrons sur deux exemples : la subduction de la lithosphère océanique et le flambage de fils visqueux dans microcanaux divergents, les deux ont un nombre de Reynolds caractéristique Re<<1. Pour le cas de la subduction d'une feuille mince, nous proposons une hybride méthode «boundary integral & thin sheet» (BITS). Après la validation en comparant ses prévisions avec celles de la boundary-element méthode, deux solutions instantanées et dépendant du temps sont effectués pour analyser la subduction avec la méthode BITS. L'analyse à l'échelle de la vitesse d'immersion normalisée en fonction de «la rigidité en flexion» de la feuille est confirmée par nos prédictions numériques. Pour des rapports de viscosité modérée (≈100), la feuille amincit sensiblement quand elle coule, mais pas assez pour conduire à la «rupture de la dalle» que l'on observe dans plusieurs zones de subduction sur Terre. Ensuite, le code BLEU parallèle pour écoulements polyphasiques est utilisé à simuler pliage visqueux tridimensionnel dans des microcanaux divergent. Nous avons réalisé une étude paramétrique comprenant cinq simulations dans lequel le rapport de débit volumétrique, le rapport de viscosité, le nombre de Reynolds, et la forme de la chaîne ont été modifiées par rapport à un modèle de référence. Le fil devient instable à une instabilité de pliage en raison de la contrainte de compression longitudinale. L'axe de pliage initial peut être parallèle ou perpendiculaire à la dimension étroite de la chambre. Dans le premier cas, le pliage transforme lentement au pliage perpendiculaire au moyen d'une torsion, ou peut disparaître totalement<br>The hydrodynamics of thin (sheet-like) and slender (filamentary) bodies of viscous fluid immersed in a second fluid with a different viscosity is studied. Here we focuses on two examples: the subduction of oceanic lithosphere and the buckling of viscous threads in diverging microchannels, both have a characteristic Reynolds number Re<<1. A hybrid boundary integral & thin sheet method (BITS) is build for the subduction of 2D immersed sheet. After the validation by comparing with the results of full boundary elements method, both instantaneous and time-dependant soloutions are done to analyze the subduction with the BITS method. The scaling analysis of the normalized sinking speed V/V_Stokes as a function of the sheet's 'flexural stiffness' is confirmed by our numerical predictions. For moderate viscosity ratios (≈100), the sheet thins substantially as it sinks, but not enough to lead to the ‘slab breakoff’ that is observed in several subduction zones on Earth. Next, the parallel code BLUE for multi-phases flows is used to simulate the 3-dimensional viscous folding in diverging microchannels. We performed a parameter study comprising five simulations in which the flow rate ratio, the viscosity ratio, the Reynolds number, and the shape of the channel were varied relative to a reference model. The thread becomes unstable to a folding instability due to the longitudinal compressive stress. The initial folding axis can be either parallel or perpendicular to the narrow dimension of the chamber. In the former case, the folding slowly transforms via twisting to perpendicular folding , or may disappear totally
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Mechergui, Olfa. "Etude numérique des transferts de masse et de chaleur en convection naturelle dans un canal : influence de la forme de la paroi." Thesis, Perpignan, 2017. http://www.theses.fr/2017PERP0020/document.
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Le présent travail apporte une contribution à la compréhension des mécanismes des transferts combinés de chaleur et de masse en convection naturelle lors de l’évaporation d’un film liquide d’eau d’épaisseur négligeable dans un canal vertical ondulé. L’écoulement est laminaire et bidimensionnel. Les équations régissant le phénomène sont résolues à l’aide d’une méthode aux volumes finis et le traitement du couplage vitesse-pression est réalisé par la méthode de projection. Les influences de la densité de flux de chaleur, de la température ainsi que l’humidité de l’air à l’entrée et la forme de la paroi du canal sur les transferts sont étudiées. Les résultats sont présentés sous la forme de ligne de courant, d’isothermes et d’iso-concentrations.Les simulations numériques effectuées ont permis l’étude détaillée de la structure de l’écoulement ainsi que des champs thermiques et massiques. Nous représentons également, les nombres de Nusselt et de Sherwood<br>The present work is a contribution to the understanding of the mechanisms of combined heat and mass transfers in natural convection during the evaporation of a liquid film with negligible thickness in a wavy vertical channel. The flow is laminar and two-dimensional. The equations governing the phenomenon are resolved using the finite volumes method and the treatment of the coupling between velocity and pressure is carried out by the projection method. The influences of the heat flux density, the temperature and the humidity of the inlet air and the shape of the channel wall on the transfers are studied. The results are presented in the form of cstreamlines, isotherms and iso-concentrations.The numerical simulations carried out have allowed the detailed study of the flow structure as well as the thermal and mass fields. We also represent the Nusselt and Sherwood numbers
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Anxionnaz, Zoé. "Etude de l’influence de la géométrie des canaux sur les performances d’un réacteur/échangeur." Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT024G/document.
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Le couplage de la réaction et de l’échange thermique au sein du même appareil est intéressant lors de la mise en oeuvre de synthèses exothermiques. L’appareil étudié est un échangeur/réacteur fonctionnant en continu dont la structure est basée sur celle des échangeurs de chaleur à plaques. Le passage du batch au continu n’est pas sans difficultés et une des manières d’intensifier les transferts tout en conservant un temps de séjour suffisant (régime laminaire) est de structurer, en 2D, le chemin réactionnel. Les caractérisations expérimentales et numériques de différentes géométries de canaux ondulés ont permis de comprendre les mécanismes qui influencent les performances thermohydrauliques et le comportement des écoulements. Des corrélations reliant les critères de performance au nombre de Dean ont été établies et la démarche d’optimisation d’une géométrie en fonction des contraintes d’utilisation a pu être définie. Les premiers pas vers l’extrapolation font l’objet de la dernière partie de ces travaux et présentent un enjeu important pour le développement industriel de ces technologies. Les résultats de cette étude ont souligné l’intérêt d’un paramètre adimensionnel caractéristique : le nombre de Dean interne, qui permet de conserver les performances thermo-hydrauliques et donc de prédire leur évolution lors du processus de changement de taille<br>Coupling reaction and heat transfer in the same unit is an interesting way to perform exothermic reactions. The studied apparatus is a continuous heat exchanger/reactor. Its structure is based on plate heat exchangers’ one. The main difficulty when transposing batch reactions to continuous ones is to intensify the heat and mass transfers and maintain at the same time enough residence time (laminar regime). A way to remove this barrier is to structure in two dimensions the chemical path in order to obtain a wavy channel. The experimental and numerical characterizations of several wavy geometries allowed us to understand the mechanisms’ impact on the thermo-hydraulic performances and on the flow behaviour. The performances criteria have been correlated to the Dean number and the optimisation of the geometry has been made according to industrial specifications. Finally, the scale-up procedure has been studied. Our results showed that the conservation of a characteristic number: the internal Dean number allows the prediction of the performances and of the flow behaviour when the characteristic size of the wavy channel increases
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Dupuy, Dorian. "Analyse et modélisation de l'interaction entre thermique et turbulence dans les récepteurs solaires à haute température." Thesis, Perpignan, 2018. http://www.theses.fr/2018PERP0038/document.
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Dans les centrales solaires à tour, le flux solaire est concentré vers un récepteur solaire où son énergie est transférée à un fluide caloporteur. L'écoulement au sein du récepteur solaire est turbulent, fortement anisotherme et à bas nombre de Mach. L'optimisation du récepteur solaire exige une meilleure compréhension et modélisation de l'interaction entre la température et la turbulence. Cette thèse cherche à y contribuer selon deux approches. Tout d'abord, on étudie les échanges énergétiques entre les différentes parties de l'énergie totale. On propose pour cela une nouvelle représentation des échanges énergétiques, fondée sur la moyenne de Reynolds. Cette représentation permet la caractérisation, à partir de simulations numériques directes d'un canal plan bipériodique anisotherme, de l'effet du gradient de température sur les échanges énergétiques associées à l'énergie cinétique turbulente dans les domaines spatial et spectral. Ensuite, on étudie la simulation des grandes échelles des équations de bas nombre de Mach. En utilisant les résultats de simulations numériques directes, on identifie les termes sous-mailles spécifiques à modéliser lorsque l'on utilise le filtre classique, non pondéré, et lorsque l'on utilise le filtre de Favre, pondéré par la masse volumique. Dans les deux cas, on évalue a priori la performance de différents modèles sous-mailles. La pertinence des modèles est vérifiée a posteriori par la réalisation de simulation des grandes échelles<br>In solar power towers, the solar flux is concentrated towards a solar receiver, wherethrough its energy is transferred to a heat transfer fluid. The flow in the solar receiver is turbulent, strongly anisothermal and at low Mach number. The optimisation of the solar receiver requires a better understanding and modelling of the interaction between temperature and turbulence. In this thesis, this is investigated following two approaches. First, we study the energy exchanges between the different parts of total energy. To this end, a new representation of the energy exchanges, based on the Reynolds averaging, is established. The representation allows the characterisation, from direct numerical simulations of a strongly anisothermal channel flow, of the effect of the temperature gradient on the energy exchanges associated with turbulence kinetic energy in the spatial and spectral domains. Second, we study the large-eddy simulation of the low Mach number equations. Using the results of direct numerical simulations, we identify the specific subgrid terms to model when the unweighted classical filter is used and when the density-weighted Favre filter is used. In both cases, the performance of different subgrid-scale models is assessed a priori. The relevance of the subgrid-scale models is then verified a posteriori by carrying out large-eddy simulations
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Bauer, Frédéric. "Transport et production dans les écoulements turbulents de paroi à des nombres de Reynolds modérés." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI033/document.
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L'approche de simulation numérique directe est utilisée pour la simulation d'un écoulement en canal pleinement turbulent afin d'étudier l'influence des grandes échelles de l'écoulement ainsi que la dynamique du transport des contraintes de Reynolds et de la vorticité. Les simulations sont réalisées sur un domaine de calcul de grande taille afin de pouvoir capturer l'intégralité des grandes structures de l'écoulement, et portent sur une gamme relativement étendue de nombres de Reynolds (Reτ =180, 395, 590 et 1100) allant des écoulements faiblement turbulents à des écoulements modérément turbulents. L'invariance remarquable des fluctuations de vorticité normale est expliquée à travers une analyse spectrale de la vorticité. L'étude des différents termes du transport de l'intensité turbulente de la vorticité révèle par ailleurs que le pic de production de la vorticité transverse est situé à proximité immédiate de la paroi et pourrait ouvrir la voie à des stratégies de réduction de la traînée basées sur la réduction de la vorticité transverse. Le transport des contraintes de Reynolds dans la couche interne et dans la couche de recouvrement est également étudié. A proximité des parois, la dépendance des termes de transport avec le nombre de Reynolds dans les échelles internes montre que ces dernières ne suffisent pas à caractériser la dynamique des contraintes de Reynolds dans cette zone. Cette insuffisance des échelles internes nous a amenés à nous intéresser plus particulièrement au processus de production à travers les statistiques de la production conditionnées par le passage par niveau des fluctuations de la vitesse normale ou longitudinale. Cette étude nous a permis d'identifier les fluctuations qui contribuent le plus à la production et celles qui sont à l'origine de la dépendance avec le nombre de Reynolds<br>The direct numerical simulations of a fully turbulent channel flow are investigated to study the large scales effects on the flow quantities such as the Reynolds stresses and vorticity transport processes. Large computational domains are used so as to cover the largest scales of the flow. The simulations are performed in a wide range of Reynolds numbers (Reτ=180, 395, 590 and 1100) going from weakly to moderately high Reynolds number turbulent flows. The invariance of the wall-normal vorticity fluctuations scaled in wall variables in the inner layer versus the Reynolds number is analyzed using a spectral analysis. The vorticity transport equations are investigated in detail, presumably for the first time. The transport mechanism of the Reynolds shear stresses are subsequently analyzed in the inner layer and the overlapping zone. In the wall layer, different terms of the Reynolds stresses transport expressed in inner scales depend on the Reynolds number. This scaling failure lead us to focus on the statistics of the production when the streamwise or normal velocity fluctuations cross a given level, through the conditional Palm statistics. The main aim is to identify those amplitudes of the fluctuations that contribute more to the production and those which are responsible for the production Reynolds dependence
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Guillermin, Nicolas. "Implémentation matérielle de coprocesseurs haute performance pour la cryptographie asymétrique." Phd thesis, Université Rennes 1, 2012. http://tel.archives-ouvertes.fr/tel-00674975.
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Dans cette thèse, je propose des architectures de coprocesseurs haute performance pour implémenter les primitives de cryptographie asymétrique, comme le RSA, les courbes elliptiques ou le couplage. Les coprocesseurs décrits dans cette thèse ont été implémentés dans des FPGA, et présentent des performances jamais égalées auparavant dans la littérature publique sur ce type de technologie. La particularité de ces architectures est l'utilisation du Residue Number System, un mode de représentation alternatif qui utilise les restes chinois pour calculer efficacement les opérations arithmétiques sur les grands nombres. Ces travaux permettent de confirmer expérimentalement les avantages théoriques de ce mode de représentation pour l'arithmétique modulaire, issus de [14, 13, 43]. Au bénéfice théorique que le RNS apporte s'ajoute une forte capacité de parallélisation qui permet d'obtenir des designs réguliers et pipelinés, proposant une fréquence maximale importante tout en réalisant les opérations modulaires dans un nombre très faible de cycles, et ce quelle que soit la taille des nombres. A titre d'exemple, une multiplication scalaire sur une courbe de 160 bits s'effectue en 0.57 ms sur un Altera Stratix, et en 4 ms pour une courbe de 512 bits, là ou les techniques de représentation classiques réalisent la même opération en le double de temps, à technologie équivalente (excepté pour des courbes particulières). Dans le cas du couplage, le gain est encore plus intéressant, puisqu'il a permis une division par 4 de latence de la meilleure implémentation sur corps de grande caractéristique au moment de la publication de [35], et la première implémentation d'un couplage à 128 bits de sécurité sur corps de grande caractéristique à descendre en dessous de la milliseconde. Enfin, je démontre la capacité du RNS à sécuriser une implémentation haute performance, en proposant 2 contre-mesures contre les canaux auxiliaires et les fautes s'adaptant efficacement sur les coprocesseurs et pouvant être utilisées pour toutes les primitives cryptographiques basées sur l'arithmétique modulaire de grands nombres.
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Yuvaraj, Rakesh. "Analyse de la cascade d’ ́energie dans une couche limite turbulente." Electronic Thesis or Diss., Centrale Lille Institut, 2021. http://www.theses.fr/2021CLIL0012.
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Ce travail consiste à étudier la cascade d’ énergie échelle par échelle dans les écoulements turbulents limités par des parois. L’ équation de Karman-Howarth-Monin-Hill (KHMH)est une équation d’ évolution de δu2, qui est directement liée au contenu énergétique dans l’espace des échelles et intègre différents processus associés aux transferts d’énergie dans l’espace physique et l’espace d’échelle (cascade). Le pic de la moyenne spatio-temporelle du terme cascade se met `a l’ échelle avec la micro- échelle de Taylor modifié dans une région éloignée de la paroi. Le terme de dérivée temporelle modifiée instantanée et le terme de pression sont fortement corrélés avec les deux termes de transfert d’ énergie. Une valeur positive de la moyenne spatio-temporelle du terme de cascade observée au niveau de la zone tampon se déplace vers des échelles plus élevées dans le sens de l’envergure à mesure que la distance à la paroi augmente, ce qui suggère une combinaison de cascade inverse et de tourbillon attaché à la paroi dans la physique de l’ écoulement. L’utilisation d’une expérience de double PIV stéréoscopiques indépendantes a permis de d ébruiter les statistiques, ce qui a aidé à calculer certaines parties des termes de l’équation KHMHdans l’expérience des flux ZPG-TBL, permettant ainsi des mesures près de la paroi à des nombres de Reynolds plus élevés<br>This work aims to investigate the scale-by-scale energy cascade in wall-bounded turbulentflows. Karman-Howarth-Monin-Hill (KHMH) equation is an evolution equation of δu2,which is directly linked to energy content in the scale space and incorporates different processes associated with energy transfers in both physical and scale-space (cascade).The peak of the Spatio-temporal average of cascade term scales with the modified Taylor microscale in the region away from the wall. The instantaneous modified time derivative term and pressure term correlates strongly with the two energy transfer terms. A positive value of the Spatio-temporal average of cascade term observed at the buffer layer moves tohigher spanwise scales as the wall distance increases, suggesting a combination of inverse cascade and wall-attached eddy in the physics of the flow. The use of two independent Stereoscopic PIV experiments allowed to denoise the statistics, which helped to compute some parts of KHMH equation terms in the ZPG-TBL flows experiment, thereby enablingmeasurements close to the wall at higher Reynolds numbers
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Laguillaumie, Marie-Océane. "Exploration multi-omique de la maladie résiduelle minimale dans deux modèles syngéniques murins de dormance tumorale de leucémie myéloïde et de mélanome." Electronic Thesis or Diss., Université de Lille (2022-....), 2024. http://www.theses.fr/2024ULILS031.
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État de l’art : La dormance tumorale est une stratégie de résistance utilisée par les cellules cancéreuses. Elle constitue un obstacle majeur dans la thérapie du cancer, puisqu’elle mène à la maladie résiduelle minimale (MRD) et augmente le risque de rechute. Bien que cliniquement significatifs, les mécanismes derrière la dormance tumorale et la MRD ne sont pas bien compris. Nous avons utilisé deux modèles murins syngéniques de leucémie myéloïde et de mélanome élaborés par le laboratoire pour explorer les profils génétiques, épigénétiques, transcriptomiques et protéomiques liés à la dormance tumorale. Par cette approche multi-omique, nous avons cherché à découvrir les processus moléculaires conduisant à la MRD et à identifier des cibles thérapeutiques potentielles.Résultats :Nous avons réalisé une analyse multi-omique complexe incluant le séquençage de l'exome entier (WES), l'analyse des variations du nombre de copies (CNV), l'immunoprécipitation de la chromatine suivie du séquençage (ChIP-seq) et des investigations du transcriptome et du protéome. L'analyse WES a identifié un chevauchement subtil de mutations génétiques entre les modèles de dormance de mélanome et de leucémie, avec de nombreuses mutations trouvées exclusivement dans les cellules de dormance. Ces signatures génétiques spécifiques suggèrent que les pressions sélectives durant la MRD peuvent conférer une résistance au microenvironnement ou aux traitements. En combinant les données CNV, les marques d'histones et les signatures d'expression génique transcriptomique avec l'analyse d'enrichissement de Gene Ontology (GO), nous avons identifié des rôles fonctionnels potentiels de ces gènes mutés et obtenu des informations sur les voies impliquées dans la MRD. De plus, en comparant les "gènes MRD murins" avec les données correspondantes aux maladies humaines provenant de bases de données publiques,nos travaux soulignent des caractéristiques communes liées à la progression de la maladie. L'analyse protéomique, combinée aux investigations génétiques multiomiques,a révélé une signature protéique distincte dans les cellules de dormance avec une implication minimale des mécanismes génétiques. L'analyse 'enrichissement des voies a mis en évidence les processus métaboliques, de différenciation et de remodelage du cytosquelette impliqués dans la MRD. Enfin, nous avons identifié 11 protéines exprimées différemment dans les cellules de dormance de ces deux pathologies. Conclusions : Notre recherche met en évidence la nature complexe de la dormance tumorale,impliquant à la fois des éléments génétiques et non génétiques. En comparant les données génomiques, transcriptomiques, protéomiques et épigénomiques, nous fournissons un aperçu approfondi du paysage moléculaire associé à la MRD. Ces résultats posent une base solide pour de futures études et suggèrent des directions prometteuses pour le développement de thérapies ciblées pour la MRD chez les patients atteints de leucémie et de mélanome. Cela souligne la nécessité de prendre en compte à la fois des facteurs génétiques et non génétiques dans les stratégies de traitement<br>Background : Tumor dormancy, a resistance strategy used by cancer cells, is a major impediment in cancer therapy, leading to minimal residual disease (MRD) and increasing the risk of relapse. Although clinically significant, the mechanisms behind tumor dormancy and MRD are not well understood. In this research, we employed two syngeneic murine models of myeloid leukemia and melanoma to explore the genetic,epigenetic, transcriptomic, and proteomic profiles linked to tumor dormancy. By applying a multiomics approach, we aimed to uncover the molecular processes driving MRD and identify possible therapeutic targets. Results : We performed a comprehensive omics analysis that included whole-exome sequencing (WES), copy number variation (CNV) analysis, chromatin immunoprecipitation followed by sequencing (ChIP-seq), and investigations of the transcriptome and proteome. The WES analysis identified a limited overlap of gene mutations between the melanoma and leukemia dormancy models, with many mutations found exclusively in dormant cells. These unique genetic signatures suggest that selective pressures during MRD may provide resistance to the surrounding microenvironment or treatments. Combining CNV data, histone marks, and transcriptomic gene expression signatures with Gene Ontology enrichment analysis,we identified the potential functional roles of these mutated genes and gained insights into the pathways involved in MRD. Furthermore, by comparing "murine MRD genes"with corresponding human disease data from public databases, we identified common features related to disease progression. Proteomic analysis, integrated with multi-omics genetic investigations, revealed a distinct protein signature in dormant cells with minimal involvement of genetic mechanisms. Pathway enrichment analysis pointed to the metabolic, differentiation, and cytoskeletal remodeling processes involved in MRD. Ultimately, we identified 11 proteins that were differentially expressed in dormant cells across both types of pathology. Conclusions : Our research highlights the intricate nature of tumor dormancy, involving both genetic and non-genetic elements. Through the comparison of genomic,transcriptomic, proteomic, and epigenomic data, we deliver an extensive overview of the molecular landscape associated with minimal residual disease. These findings laya solid groundwork for future studies and suggest promising directions for developing targeted therapies for MRD in leukemia and melanoma patients. This underscores the necessity of incorporating both genetic and non-genetic factors into treatment strategies
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Dosso, Fangan Yssouf. "Contribution de l'arithmétique des ordinateurs aux implémentations résistantes aux attaques par canaux auxiliaires." Electronic Thesis or Diss., Toulon, 2020. http://www.theses.fr/2020TOUL0007.
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Cette thèse porte sur deux éléments actuellement incontournables de la cryptographie à clé publique, qui sont l’arithmétique modulaire avec de grands entiers et la multiplication scalaire sur les courbes elliptiques (ECSM). Pour le premier, nous nous intéressons au système de représentation modulaire adapté (AMNS), qui fut introduit par Bajard et al. en 2004. C’est un système de représentation de restes modulaires dans lequel les éléments sont des polynômes. Nous montrons d’une part que ce système permet d’effectuer l’arithmétique modulaire de façon efficace et d’autre part comment l’utiliser pour la randomisation de cette arithmétique afin de protéger l’implémentation des protocoles cryptographiques contre certaines attaques par canaux auxiliaires. Pour l’ECSM, nous abordons l’utilisation des chaînes d’additions euclidiennes (EAC) pour tirer parti de la formule d’addition de points efficace proposée par Méloni en 2007. L’objectif est d’une part de généraliser au cas d’un point de base quelconque l’utilisation des EAC pour effectuer la multiplication scalaire ; cela, grâce aux courbes munies d’un endomorphisme efficace. D’autre part, nous proposons un algorithme pour effectuer la multiplication scalaire avec les EAC, qui permet la détection de fautes qui seraient commises par un attaquant que nous détaillons<br>This thesis focuses on two currently unavoidable elements of public key cryptography, namely modular arithmetic over large integers and elliptic curve scalar multiplication (ECSM). For the first one, we are interested in the Adapted Modular Number System (AMNS), which was introduced by Bajard et al. in 2004. In this system of representation, the elements are polynomials. We show that this system allows to perform modular arithmetic efficiently. We also explain how AMNS can be used to randomize modular arithmetic, in order to protect cryptographic protocols implementations against some side channel attacks. For the ECSM, we discuss the use of Euclidean Addition Chains (EAC) in order to take advantage of the efficient point addition formula proposed by Meloni in 2007. The goal is to first generalize to any base point the use of EAC for ECSM; this is achieved through curves with one efficient endomorphism. Secondly, we propose an algorithm for scalar multiplication using EAC, which allows error detection that would be done by an attacker we detail
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Manzoor, Shaukat. "INCREASES IN THE NUMBER OF FROST- FREE DAYS ACROSS CANADA DURING WINTER PERIOD." Thesis, 2013. http://hdl.handle.net/10214/7445.
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An annual analysis of data from 11 weather stations across Canada was examined for temporal changes in the number of frost free days (FFDs) per winter. From 1940 to 2009, Canada has experienced an increase in the number of FFDs with an average of 12 days in 100 years. The numbers of FFDs per winter increased exponentially when mean WDMT rises steadily. The best fit normal distribution function of WDMT in recent decades has shifted toward the hotter part of the curve.
The predicted numbers of FFDs per winter from the exceedance probability (EP) has increased exponentially when mean WDMT rise steadily. The EP model displayed a close comparison between the predicted and the measured number of FFDs. The EP model also provides a useful tool for making predictions about the increase in the number of frost-free days at any single station, given the rate of rise in minimum temperatures
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Stetter, Kim Larissa. "The influence of number of channels on consumer’s brand perceptions : a comparison across different generations and their attitudes." Master's thesis, 2019. http://hdl.handle.net/10400.14/26963.
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In the last decade, new retail approaches have arisen and companies have enlarged their shopping channel portfolio. The variety ranges from solely a website to a huge diversified offer including e.g. store, catalog, website, and app, to fulfill the needs of potential customer and keep pace with their competitors. As consumers become more accustomed to using several channels due to the numerous opportunities they can select from, and companies have to invest high amounts into their channel management, an increasing importance can be attributed to the comprehension of the channel number impact. This dissertation investigates the shopping channel offer influence on brand perception in connection with different generations, channel attitudes, shopping orientations and product involvement in an appealing branch. The results indicate a general preference for higher channel quantity, based on a higher channel offer leading to higher brand perception. High product involvement increases the need for more channels. Furthermore, divergences occur in shopping orientation and channel attitudes by comparing different generations. Brand perception is also directly impacted by the different generations and high involvement products. Therefore, retailers need to offer consumers an adequate number of channels, especially in a high involvement industry, and target the generations properly by taking their own shopping orientations and channel attitudes into account.<br>Na última década, surgiram novas abordagens de retalho e as empresas diversificaram o portefólio de canais de compras. A variedade varia entre um único website a uma vasta oferta diversificada, p.e. loja, catálogo, website e aplicação, para atender às necessidades dos potenciais clientes e acompanhar a concorrência. À medida que os consumidores se acostumam a utilizar vários canais, devido às inúmeras oportunidades à sua disposição, e as empresas precisam de elevados investimentos na gestão dos seus canais, a compreensão do impacto do número de canais assume uma importância cada vez maior. Esta dissertação investiga a influência da oferta de canais de vendas na perceção de marcas relativamente às diferentes gerações, atitudes em relação ao canal, orientações de compra e envolvimento do produto num ramo apelativo. Os resultados indicam uma preferência geral por uma maior quantidade de canais, já que uma elevada oferta de canais leva a maior perceção da marca. O elevado envolvimento do produto aumenta a necessidade em possuir mais canais. Além disso, as divergências ocorrem na orientação de compra e atitudes relativamente ao canal ao comparar diferentes gerações. A perceção de marca sofre igualmente o impacto direto das diferentes gerações e elevado envolvimento dos produtos. Assim, os retalhistas precisam de oferecer aos consumidores um elevado número de canais, particularmente numa indústria de elevado envolvimento, e visar adequadamente as gerações, tendo em conta as suas próprias orientações de compra e atitudes relativamente ao canal.
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Hurd, Thomas E. "Factors limiting moose numbers and their interactions with elk and wolves in the central Rocky Mountains, Canada." Thesis, 1999. http://hdl.handle.net/2429/9658.
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Numbers of moose declined in Banff National Park between the mid-1940's and present.
This coincided with increases in abundance of both elk and wolves. To explain the
decline, I tested several predictions related to exploitative competition with elk, and
apparent competition mediated by wolves. The relationship I found between moose and
elk winter pellet abundance was consistent with the inverse density pattern expected if
exploitative competition and/or apparent competition were operative. Interactions
between the two cervids and a shared food resource - willow - supported several of the
key criteria required to demonstrate exploitative competition. The two cervids overlapped
in resource use, and use by elk probably reduced resource availability to moose. The large
asymmetries in distribution, abundance, diet breadth, diet overlap, and browse utilization
provided the conditions necessary for elk to dominate competitive interactions.
Interactions between predators (wolf and grizzly bear) and the two cervids revealed the
potential for apparent competition where the impact on secondary prey, moose, was
greater than on primary prey, elk. Predation rates on radio-collared moose appeared
unsustainable. The two forms of "competition" operated at different scales, and appeared
additive in their negative effect on moose. Exploitative competition was localized in areas
of high elk density and apparent competition (predation) operated throughout the study
area. My findings contrast with the usual study of mixed competition-predation systems
where the two factors provide a mechanism for coexistence.
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Rumore, Jillian. "Application and interpretation of multiple locus variable number tandem repeat analysis for Escherichia coli O157:H7 laboratory surveillance and outbreak response in Canada, 2008-2012." 2014. http://hdl.handle.net/1993/23863.
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To enhance outbreak investigations of Shiga toxin-producing Escherichia coli O157:H7, PulseNet Canada has recently applied Multiple Locus Variable Number Tandem Repeat Analysis (MLVA) as a supplemental subtyping tool in combination with the gold standard subtyping method Pulsed-field Gel Electrophoresis (PFGE) for enhanced resolution of isolates exhibiting indistinguishable/highly similar PFGE patterns. The objective was to assess the discriminatory power and level of specificity MLVA offers for outbreak detection and response. Results demonstrate that MLVA provides a statistically significant increase in discriminatory power for outbreak investigations (0.998) compared to PFGE alone (0.993). MLVA was able to provide additional resolution over PFGE analysis and generally agreed with PFGE when isolates were identical and epidemiologically linked. MLVA shows great promise as a molecular epidemiological tool to complement PFGE, as it improves case categorization during outbreak investigations, and the greatest benefits of MLVA may be realized during routine surveillance, when epidemiological information is not available.
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Allaith, Zainab A. "Engagement in Reading and Access to Print: The Relationship of Home and School to Overall Reading Achievement Among Fourth Grade English Speakers." Thesis, 2013. http://hdl.handle.net/1969.1/149385.
Full textAbstract:
The present study puts forward two models which examine the relationship between at home at school variables of (1) engagement in shared and independent reading and (2) access to print with reading achievement. Participants were fourth grade English speakers from Canada (Alberta, British Columbia, and Nova Scotia), New Zealand, England, and USA. Data from the Progress in International Reading Literacy Study (PIRLS) questionnaires and reading achievement test were used to design the two models, and Hierarchical linear modeling (HLM) was used to analyze the data where students (Level-1) were nested within classrooms (Level-2).
The results of the Engagement in Reading Model demonstrate that activities of shared reading at home and at school did not statistically significantly relate or related negatively with reading achievement. Parents helping their children with school readings emerged as the strongest negative predictor of reading achievement in the entire model. However, the relationship between how often participants talked with their families about what they read on their own and reading achievement was positive. Additionally, independent reading at school, reading for fun at home, and reading printed material (books and magazines) at home predicated reading achievement positively; reading for homework did not predict reading achievement; and reading for information and reading on the internet at home predicted reading achievement negatively.
The results of the Access to Print Model demonstrate that while access to books and other reading material at home related positively with reading achievement, access to books and other reading material at school did not overall relate to students’ reading achievement. Additionally, access to the library, generally, did not relate to reading achievement; and when statistical significance was found it was not replicated in all or even most of the countries.
Based on the results of the present study, it is recommended that fourth graders be given ample opportunities to read books of their own choosing independently at school, and to develop students’ habits and motivation to read for leisure during their free after school time. Additionally, children should be provided with ample access to reading material at home which is geared towards their interests.