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Dissertations / Theses on the topic 'Ground loops'
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1
Myllylä, K. (Kari). "On the solvability of groups and loops." Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:9514269055.
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The dissertation consists of three articles in which the solvability of groups and the solvability of loops are considered. The first parts of the thesis survey some basic information and results on transversals and loops. The summarizing parts provide the three main results for the solvability of groups and loops.
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Bauer, Sven. "Loops on real Stiefel-manifolds." Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367371.
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The central object of the study in this thesis is ΩO(n), the space of closed continuous loops on an orthogonal group O(n) based at the identity-element 1 Ε O(n). The space ΩO(n) carries a group structure given by pointwise multiplication of paths in the group O(n). This makes it an infinite dimensional Lie group. A filtration of ΩO(n), more precisely of the subspace of 'polynomial' loops, is constructed. This can be thought of as the 'real' analogue of the Mitchell-Richter filtration of ΩSU(n). Our filtration of ΩO(n) splits stably and O(n)-equivariantly in the cases n = 3, 4. We obtain: In contrast to the complex case no general splitting result can hold (this follows from work by Hopkins on stable indecomposability of ΩSp(2)). The thesis also investigates the topology of the loopspace of a real Stiefel-manifold. A stable O(n)-equivariant splitting for the fibrewise loop-space of a projective bundle is used to give a splitting for the free loop-space LRPn on a real projective space.
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Pacheco, Rui. "Harmonic maps and loop groups." Thesis, University of Bath, 2004. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404621.
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Zhou, Yongxin. "Alternative algebras and RA loops." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0002/NQ42490.pdf.
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Souaid, Charbel. "Identification and characterization of Polycomb repressed gene-enhancer loops." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS015.
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Dans les cellules souches embryonnaires de souris (mESCs), le groupe de protéines Polycomb (PcG) répriment les gènes de développement en participant ainsi à la maintenance de l’état de pluripotence. Ce complexe dépose la H3K27me3au niveau des éléments régulateurs induisant une compaction de la chromatine. Cette marque forme en plus des marquesactives H3K4me3 présentes des domaines bivalents. Etrangement, des boucles d’ADN dites entre le promoteur et enhancer, généralement associé à l’activation du gènes, sont observées au niveau des gènes bivalents avant leur activation.On suppose que la fonction du PcG pourrait être de neutraliser l'enhancer conférant une future activation rapide des gènes.Au cours de ma thèse, j’ai identifié les boucles d’ADN formé par les réprimés par PcG dans les mESCs. Pour cela,j’ai effectué un profilage épigénomique de 4 marques d'histones et identifié près de 2500 promoteurs bivalents et 13000enhancers. En utilisant des données publiées de Hi-C à haute résolution, j’ai identifié toutes les boucles formées par les domaines bivalents. Etonnement, j’ai pu identifier que de nombreux gènes réprimés par PcG interagissent avec des enhancers actifs. Cette observation a été suivie d'une validation par le 4C-seq. De plus, j’ai effectué une caractérisation fonctionnelle des boucles en utilisant deux approches. Tout d'abord, j'ai mis en place, en collaboration avec D. Bourc'his(Institut Curie), un système de culture de mESCs (2i + VitC) où le taux de H3K27me3 est réduit. J'ai effectué un profilage épigénomique similaire révélant que les promoteurs réprimés par PcG ont perdu la marque H3K27me3. En RNA-seq, j’ai démontré que l’expression des gènes ne change pas après le PcG soit détacher des promoteurs.. Ensuite, par la réalisation de plusieurs validations en 4C-seq j’ai démontré que les interactions avec les enhancers ne sont pas affecté alors que la moitié des enhancers interagissant perdent leurs marques activatrices. Dans le système 2i+VitC, ces gènes semblent être réprimés par un autre mécanisme suite à la perte du PcG. De plus, j’utilise une approche ciblée pour enlever localement laH3K27me3 de deux gènes bivalents en utilisant le système Cette technique est en cours d’optimisation.Notre étude est la plus systématique au niveau génomique des boucles d'ADN dans le cadre de la régulation des gènes PcG. Notre étude révèle une nouvelle fonction du PcG qui est la répression de boucle d’ADN déjà établies entre promoteurs et enhancersIn the mouse embryonic stem cells (mESCs), Polycomb Group Proteins (PcG) repress developmental genes and thereby participating in the maintenance of the pluripotency. PcG repress genes by depositing the H3K27me3 histone marks on their regulatory elements, followed by chromatin compaction. In addition to the H3K27me3 marks, those genes carry H3K4me3 active marks and were characterized as bivalent. Intriguingly, at many PcG repressed genes, DNA loops can be observed with enhancer elements, which are normally thought to have an activating function. The aim of my project is to both describe and mechanistically dissect the function of Polycomb repressed promoter – enhancer loops.During my PhD, I aimed firstly to identify all promoter–enhancer loops involved by PcG repressed genes in mESCs. I have performed ChIP-seq profiling of 4 histone marks and identified around 2500 PcG repressed promoters and 13000 enhancers. Using a recently published high-resolution Hi-C data in mESCs, I have identified all DNA loops that are formed by PcG repressed promoters. Surprisingly, a high percentage of bivalent promoters were found to contact active enhancers. The presence of those loops were validated by ultra-high 4C-seq on selected genes and imply a small significant increase of the gene expression without leading to a complete activation of the gene. I have established a more physiological ESC model (2i+VitC) where H3K27me3 is reduced at all promoters. I have performed ChIP-seq, where bivalent promoters were all classified as H3K27me3 negative. RNA-seq experiments have showed that those genes do not become activated. 4C-seq experiments have revealed that those loops do not disappear after PcG removal, whereas the half of interacted enhancer loose their H3K27ac active marks. Those genes seem to remain repressed by an unknown mechanism. These results argue for a possible role of PcG in preparing the gene for their activation by blocking the productivity of such DNA loops. Secondly, I aimed to functionally characterize those DNA loops by using a CRISPR/dCas9 approach to completely remove H3K27me3 from two PcG repressed genes that contact active enhancers Pax6 and Nkx1-1 genes. This system is still under optimization steps.My project revealed the most systematic characterization of DNA loops under the regulation of PcG, providing important insight how PcG function to inactivate such loops. I have highlighted an additional function of PcG which the involvement in the repression of already establish loops between active enhancers and promoters and thereby blocking the productivity of such activating loops. This function is an addition to the already described repressive function of PcG on both promoters and poised enhancers
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Kim, Yunhyong. "Smooth cochain cohomology of loop groups." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621575.
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Raynor, Sophia C. "Compact symmetric multicategories and the problem of loops." Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=236493.
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The compact symmetric multicategories (CSMs) introduced by Joyal and Kock in their 2011 note 'Feynman Graphs, and Nerve Theorem for Compact Symmetric Multicategories' [JK11] directly generalise a number of unital operad types, such as wheeled properads, that admit a contraction operation as well as an operadic multiplication. These structures are known to exhibit strange behaviour related to the contraction of units, and this is problematic for [JK11]. In this thesis, I modify the construction of [JK11] to obtain non unital (coloured) modular operads as algebras for a monad defined in terms of connected graphs, and use this as a foundation for a new construction of CSMs based on special graph morphisms. A corresponding nerve theorem characterises CSMs in terms of a Segal condition. This construction sheds light, and provides some control, on the behaviour of the contracted units.
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Kim, Jeong I. "Log-Periodic Loop Antennas." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/34392.
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The Log-Periodic Loop Antenna with Ground Reflector (LPLA-GR) is investigated as a new type of antenna, which provides wide bandwidth, broad beamwidth, and high gain. This antenna has smaller transverse dimensions (by a factor of 2/pi) than a log-periodic dipole antenna with comparable radiation characteristics. Several geometries with different parameters are analyzed numerically using ESP code, which is based on the method of moments. A LPLA-GR with 6 turns and a cone angle of 30* offers the most promising radiation characteristics. This antenna yields 47.6 % gain bandwidth and 12 dB gain according to the numerical analysis. The LPLA-GR also provides linear polarization and unidirectional patterns.
Three prototype antennas were constructed and measured in the Virginia Tech Antenna Laboratory. Far-field patterns and input impedance were measured over a wide range of frequencies. The measured results agree well with the calculated results. Because of its wide bandwidth, high gain, and small size, the LPLA is expected to find applications as feeds for reflector antennas, as detectors in EMC scattering range, and as mobile communication antennas.
Master of Science
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Blomqvist, Mikael. "Construction and evaluation of a magnetoresistive ground penetrating radar system." Thesis, Uppsala universitet, Ångström Space Technology Centre (ÅSTC), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-159904.
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This Master Thesis examines the possibility to apply a magnetometer developed by the Ångstöm space technology center to a small magnetic ground penetrating radar system with dimension in the order of one dm³. The magnetometer is broadband (DC-1GHz) and miniaturized. Loop antennas are used to transmit the signal. A series of experiments have been performed in order to characterize the system, mainly examining the ability to determine distance to a target, using continuous sine wave signals and pulse trains. Standing wave patterns are formed between antenna and target and can be used for determining distance in the continuous case. When using a pulse train, the echo from the target could not be resolved using the current experiment set up, distance could therefore not be determined.
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Aloi, Daniel N. "Electromagnetic analysis of ground multipath for satellite-based positioning systems." Ohio University / OhioLINK, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1178816934.
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Balbo, Pedro Paulo Abel. "Teoremas de Sylow para loops de Moufang." reponame:Repositório Institucional da UFABC, 2016.
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Orientadora: Profa. Dra. Maria de Lourdes Merlini GiulianiDissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Matemática , 2016.
Neste trabalho foram abordados os Teoremas de Sylow para loops de Moufangnitos. A validade destes teoremas nocontexto não associativo não ocorre de maneira direta uma vez que o menor loop deMoufang finito simples tem ordem 120 e não possui subloop de ordem 5. Foi analisada aaplicação destes teoremas para duas categoriasde loops de Moufang de ordem par: os loops de Cheine os loops de Paige. Para os loops de Chein vemos que dois subloops de Sylow são conjugados. Para os loops de Paige P(q) vericamos a existência e o númerode p-subloops de Sylow.
In this work Sylow's theorems for nite Moufang loops were investigated. The validity of these theorems in a non-associative context does not occur directly as the smallest simple nite Moufang loop hasorder 120 and contains no subloopo forder 5. We analyzed the application of these theorems for two categories of Moufang loops of even order: Chein loop sand Paige loops.For Chein loops we can see that any two Sylow's sub loop sare always conjugated. For Paige loops P(q) we verifed the existence of p-Sylow subloops and studied their number.
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Pittman-Polletta, Benjamin Rafael. "Factorization in unitary loop groups and reduced words in affine Weyl groups." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/194348.
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The purpose of this dissertation is to elaborate, with specific examples and calculations, on a new refinement of triangular factorization for the loop group of a simple, compact Lie group K, first appearing in Pickrell & Pittman-Polletta 2010. This new factorization allows us to write a smooth map from the unit circle into K (having a triangular factorization) as a triply infinite product of loops, each of which depends on a single complex parameter. These parameters give a set of coordinates on the loop group of K.The order of the factors in this refinement is determined by an infinite sequence of simple generators in the affine Weyl group associated to K, having certain properties. The major results of this dissertation are examples of such sequences for all the classical Weyl groups.We also produce a variation of this refinement which allows us to write smooth maps from the unit circle into the special unitary group of n by n matrices as products of 2n+1 infinite products. By analogy with the semisimple analog of our factorization, we suggest that this variation of the refinement has simpler combinatorics than that appearing in Pickrell & Pittman-Polletta 2010.
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Swoboda, Jan. "The Yang-Mills gradient flow and loop groups /." Zürich : ETH, 2009. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18296.
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Sadasue, Gaku. "Equivalence-Singularity dichotomy for the Wiener measures on path groups and loop groups." 京都大学 (Kyoto University), 2000. http://hdl.handle.net/2433/181092.
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Soh, Mun Lok Bernard. "Hardware in the loop implementation of adaptive vision based guidance law for ground target tracking." Thesis, Monterey, Calif. : Naval Postgraduate School, 2008. http://edocs.nps.edu/npspubs/scholarly/theses/2008/Dec/08Dec%5FSoh.pdf.
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Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, December 2008.Thesis Advisor(s): Dobrokhodov, Vladimir N. ; Jones, Kevin D. "December 2008." Description based on title screen as viewed on February 2, 2009. Includes bibliographical references (p. 89-90). Also available in print.
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Anjos, Giliard Souza dos. "Half-Isomorfismos de loops automórficos." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-03052018-221550/.
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Loops automórficos, ou A-loops, são loops nos quais todas as aplicações internas são automorfismos. Esta variedade de loops inclui grupos e loops de Moufang comutativos. Loops automórficos diedrais formam uma classe de A-loops construda a partir da duplicação de grupos abelianos finitos, generalizando a construção do grupo diedral. Outra classe de A-loops é a dos loops automórficos de Lie, construda a partir de anéis de Lie, definindo-se uma nova operação entre seus elementos. Um half-isomorfismo é uma bijeção f entre loops L e L\' onde, para quaisquer x e y pertencentes a L, temos que f(xy) pertence ao conjunto . Dizemos que o half-isomorfismo f é não trivial quando f não é um isomorfismo e nem um anti-isomorfismo. Nesta tese descrevemos propriedades de half-isomorfismos de loops, classificamos os half-isomorfismos entre loops automórficos diedrais e obtivemos o grupo de half-automorfismos nesta classe. Para os loops automórficos de Lie de ordem mpar, mostramos que todo half-automorfismo é trivial.Automorphic loops, or A-loops, are loops in which every inner mapping is an automorphism. This variety of loops includes groups and commutative Moufang loops. Dihedral automorphic loops form a class of A-loops, constructed from the duplication of finite abelian groups, that generalizes the construction of the dihedral group. Another class of A-loops is the Lie automorphic loops, constructed from Lie rings, where a new operation between its elements is defined. A half-isomorphism is a bijection f between loops L and L\' where, for any x and y belong to L, we have that f(xy) belongs to the set {f(x)f(y),f(y)f(x)}. We say that half-isomorphism f is non trivial when f is neither an isomorphism nor an anti-isomorphism. In this thesis, we describe properties of half-isomorphisms of loops, we classify the half-isomorphisms between dihedral automorphic loops and we obtain the group of half-automorphisms in this class. For the Lie automorphic loops of odd order, we show that every half-automorphism is trivial.
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Bergeron-Legros, Gabriel. "Weil Representation and Central Extensions of Loop Symplectic Groups." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31516.
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In this thesis, we present the Weil representation over loop symplectic groups. Then we study the question of whether or not the Schrodinger representation and the Weil representation are continuous. Finally, we define a cocycle of the rank 2 symplectic group, adapt Kubota's theorem to this case and verify that it splits over a subgroup.
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Reis, Márcio Alexandre de Oliveira. "Loops de Bol algébricos e analíticos." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-27062010-143306/.
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Neste trabalho classificamos, a menos de isomorfismos, as álgebras de Bol de dimensão 2 sobre um corpo de característica 0. Também determinamos suas álgebras de Lie envolvente e, mostramos que existem álgebras de Bol não isomorfas cujas álgebras de Lie envolventes coorrespondentes são isomorfas. Calculamos os grupos algébricos (locais) correspondentes a cada uma das álgebras de Lie envolventes e provamos que todo loop de Bol analítico (algébrico) global de dimensão 2 sobre um corpo de característica 0 é um grupo. Exibimos exemplos de loops de Bol algébricos globais de dimensão n, para todo n > 2, e fornecemos uma condição necessária e suciente para a existência de um loop de Bol algébrico global quando a álgebra de Bol tem uma álgebra de Lie envolvente nilpotente de índice 2 sobre um corpo de característica diferente de 2.In this work, we classify up to isomorphism, the Bol algebras of dimension 2 over a eld of characteristic 0. We also determine their enveloping Lie algebras and we exhibit two non-isomorphic Bol algebras which have isomorphic enveloping Lie algebras. We determine the (local) correspondent algebraic groups of each of those enveloping Lie algebras and we show that every global analytic (algebraic) Bol loop of dimension 2 over a eld of characteristic 0 is a group. We exhibit examples of non-nilpotent solvable algebraic Bol loops in dimension n for every n > 2, and we were able to give a necessary and sucient condition to decide if a local algebraic Bol loop is global when its enveloping Lie algebra is nilpotent of index 2 and char(F) 6= 2:
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Hughes, Kyle L. "Commercial Program Development for a Ground Loop Geothermal System: G-Functions, Commercial Codes and 3D Grid, Boundary and Property Extension." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1324332345.
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Damiani, Céleste. "The topology of loop braid groups : applications and remarkable quotients." Caen, 2016. http://www.theses.fr/2016CAEN2021.
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Dans cette thèse nous étudions les groupes de tresses de cercles, nous explorons leurs applications topologiques et certains quotients remarquables. La thèse se compose de quatre parties : - Unification des formalismes pour les groupes de tresses de cercles. Plusieurs formulations ont été utilisées pour les groupes de tresses de cercles en différents domaines ; nous présentons ces interprétations et prouvons leur équivalence. - Une version topologique du théorème de Markov pour les entrelacs de tores ruban. Avec l’interprétation des tresses de cercles comme objets noués dans l’espace de dimension 4, nous présentons une version du Théorème de Markov pour les groupes de tresses de cercles avec clôture dans l’analogue du tore solide dans l’espace de dimension 4. - Invariants d’Alexander pour enchevêtrements ruban et algèbres de circuit. Nous définissons un invariant d’Alexander pour enchevêtrements ruban. De cela nous extrayons une généralisation fonctorielle du polynôme d’Alexander. Cet invariant a une signification topologique profonde, mais n’est pas simplement calculable. Nous établissons une correspondance avec le polynôme d’Alexander en plusieurs variables pour enchevêtrements introduit par Archibald pour résoudre ce problème. - Quotients des groupes de tresses virtuelles. Nous étudions les groupes de tresses de cercles symétriques, et nous en décrivons la structure. Comme conséquence nous montrons que tout entrelacs «fused » admets un représentant comme clôture d’une tresse de cercles symétrique pureIn this these we study loop braid groups, we explore some of their topological applications and some remarquable quotients. The thesis is composed by four parts:- Unifying the different approaches to loop braid groups. Several formulations are being used by researchers working with loop braid groups in different fields; we present these interpretations and prove their equivalence. - A topological version of Markov’s theorem for ribbon torus-links. Using the understanding of the interpretation of loop braids as knotted objects in the 4-dimensional space, we give a topological proof of a version of Markov theorem for loop braids with closure in a solid torus in the 4-dimensional space. - Alexander invariants for ribbon tangles. We define an Alexander invariant on ribbon tangles. From this invariant we extract a functorial generalization of the Alexander polynomial. This invariant has a deep topological meaning, but lacks a simple way of computation. To overcome this problem we establish a correspondence with Archibal’s multivariable Alexander polynomial for tangles. - Quotients of the virtual braid group. We study the groups of unrestricted virtual braids, a family of quotients of the loop braid groups, and describe their structure. As a consequence we show that any fused link admits as a representative the closure of a pure unrestricted virtual braid
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Miscione, Steven. "Loop algebras and algebraic geometry." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116115.
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This thesis primarily discusses the results of two papers, [Hu] and [HaHu]. The first is an overview of algebraic-geometric techniques for integrable systems in which the AKS theorem is proven. Under certain conditions, this theorem asserts the commutatvity and (potential) non-triviality of the Hamiltonian flow of Ad*-invariant functions once they're restricted to subalgebras. This theorem is applied to the case of coadjoint orbits on loop algebras, identifying the flow with a spectral curve and a line bundle via the Lax equation. These results play an important role in the discussion of [HaHu], wherein we consider three levels of spaces, each possessing a linear family of Poisson spaces. It is shown that there exist Poisson mappings between these levels. We consider the two cases where the underlying Riemann surface is an elliptic curve, as well as its degeneration to a Riemann sphere with two points identified (the trigonometric case). Background in necessary areas is provided.
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New, Stephen J. H. "Hamiltonian systems and loop groups applied to equations of KdV type." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60055.
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We study relationships between completely integrable Hamiltonian flows $L sb{t}( lambda$) of matricial polynomials on finite dimensional coadjoint orbits in the dual of a loop algebra and differential operators arising from points in an infinite dimensional Grassmannian Gr. Adams, Harnad, Hurtubise, and Previato have described how moment maps lead one to consider these flows, and how the systems can be integrated by constructing a linear flow $E sb{t}$ of line bundles over a curve $ tilde S$. Segal and Wilson have explained how a differential operator L and an eigenfunction called the Baker function $ psi sb{W}$ can be associated to each point $W in Gr$. In this thesis, we give a vector version of the construction described by Segal and Wilson. Then spaces $W in Gr$ correspond to sections of $E sb0$ over $ tilde S { lambda = infty }$, the r-dimensional space of Baker functions corresponds to the space of holomorphic sections of $E sb{t}$, and the differential operator L corresponds to the matricial polynomial $L sb{t}( lambda).$
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Ozel, Cenap. "On the complex cobordism of flag varieties associated to loop groups." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241783.
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Reilly, Nicholas James. "Cmos Programmable Time Control Circuit Design For Phased Array Uwb Ground Penetrating Radar Antenna Beamforming." ScholarWorks @ UVM, 2017. http://scholarworks.uvm.edu/graddis/687.
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Phased array radar systems employ multiple antennas to create a radar beam that can be steered electronically. By manipulating the relative phase values of feeding signals among different antennas, the effective radiation pattern of the array can be synthesized to enhance the main lobe in a desired direction while suppressing the undesired side lobes in other directions. Hence the radar scanning angles can be electronically controlled without employing the bulky mechanical gimbal structure, which can significantly reduce radar system size, weight and power consumption. In recent years, phased array technologies have received great attentions and are explored in developing many new applications, such as smart communication systems, military radars, vehicular radar, etc. Most of these systems are narrow band systems, where the phase delays are realized with narrow band phase shifter circuits. For the impulse ground penetrating radar however, its operating frequency spans an ultrawide bandwidth. Therefore the traditional phase shifters are not applicable due to their narrow band nature. To resolve the issue, in this study, a true time delay approach is explored which can precisely control time delays for the feeding pulse signals among different antennas in the array. In the design, an on chip programmable delay generator is being developed using Global Foundry 0.18 µm 7 HV high voltage CMOS process. The time delay control is realized by designing a programmable phase locked loop (PLL) circuit which can generate true time delays ranging from 100 ps (picoseconds) to 500 ps with the step size of 25 ps. The PLL oscillator's frequency is programmable from 100MHz to 500MHz through two reconfigurable frequency dividers in the feedback loop. As a result, the antenna beam angle can be synthesized to change from 9.59° to 56.4° with a step of 2.75°, and the 3dB beamwidth is 10°. The power consumption of the time delay circuit is very low, where the supply voltage is 1.8V and the average current is as low as 472uA.
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Gross, Paul A. II. "Commercial Program Development for a Ground Loop Geothermal System: Energy Loads, GUI, Turbulent Flow, Heat Pump Model and Grid Study." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1324258915.
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Pallekonda, Seshendra. "Bounded category of an exact category." Diss., Online access via UMI:, 2008.
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Filho, Antonio Calixto de Souza. "Sobre uma classificação dos anéis de inteiros, dos semigrupos finitos e dos RA-loops com a propriedade hiperbólica." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-30012009-163028/.
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Apresentamos duas construções para unidades de uma ordem em uma classe de álgebras de quatérnios que é anel de divisão: as unidades de Pell e as unidades de Gauss. Classificamos os anéis de inteiros de extensões quadráticas racionais, $R$, cujo grupo de unidades $\\U (R G)$ é hiperbólico para um certo grupo $G$ fixado. Também classificamos os semigrupos finitos $S$, tal que, para a álgebra unitária $\\Q S$ e para toda $\\Z$-ordem $\\Gamma$ de $\\Q S$, o grupo de unidades $\\U (\\Gamma)$ é hiperbólico. Nesse mesmo contexto, classificamos os {\\it RA}-loops $L$ cujo loop de unidades $\\U (\\Z L)$ não contém um subgrupo abeliano livre de posto dois.For a given division algebra of a quaternion algebra, we construct and define two types of units of its $\\Z$-orders: Pell units and Gauss units. Also, for the quadratic imaginary extensions over the racionals and some fixed group $G$, we classify the algebraic integral rings for which the unit group ring is a hyperbolic group. We also classify the finite semigroups $S$, for which all integral orders $\\Gamma$ of $\\Q S$ have hyperbolic unit group $\\U(\\Gamma)$. We conclude with the classification of the $RA$-loops $L$ for which the unit loop of its integral loop ring does not contain a free abelian subgroup of rank two.
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Biswas, Arindam. "Théorie des groupes approximatifs et ses applications." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS573.
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Dans la premier partie de cette thèse, nous étudions la structure des sous-groupes approximatifs dans les groupes metabéliens (groupes résolubles de classe de résolubilité 2) et montrons que si A est un tel sous-groupe K approximatif, il est K^⁰(r) contrôlée (au sens du Tao) par un groupe nilpotent où $ r désigne le rang de $ G=Fit (G) et Fit (G) $ est le sous-groupe de fitting de G. La deuxième partie est consacrée à l'étude de la croissance des ensembles dans GLn(Fq) où Fq est un corps fini. Nous montrons une borne sur le diamètre (par rapport à n'importe quel système des générateurs) pour tous sous-groupes simples finis de ce groupe. Si G est un groupe fini simple de type Lie de rang n, et son corps de base est de taille borné, le diamètre du graphe du Cayley Gamma (G;S) serait borné par exp (O (n (log n) ^ 3)) . Si la taille du corps fini Fq n'est pas borné, notre méthode donne une borne de q ^ {O (n ( log nq) ^ 3) pour le diamètre.Dans la troisième partie nous nous sommes intéressés à la croissance des ensembles dans les boucles de Moufang commutatifs. Ceux-ci sont les boucles commutatifs respectant les identités de Moufang mais sans être (nécessairement) associatifs. Nous montrons que, si les tailles des ensembles des associateurs sont bornées alors la croissance des sous-structures approximatifs dans ces boucles est similaire à celle des groupes ordinaires. De cette façon dans le cadre des boucles de moufang commutatifs finiment engendré on a un théorème de structure pour ses sous-boucles approximatifs.Mots-clefs -sous-groupes approximatifs, groupes résolubles, diamètres des groupes, boucles de moufang commutatifsIn the first part of this thesis, we study the structure of approximate subgroups inside metabelian groups (solvable groups of derived length 2) and show that if A is such a K-approximate subgroup, then it is K^(O(r)) controlled (in the sense of Tao) by a nilpotent group where r denotes the rank of G=Fit(G) and Fit(G) is the fitting subgroup of G.The second part is devoted to the study of growth of sets inside GLn(Fq) , where we show a bound on the diameter (with respect to any set of generators) for all finite simple subgroups of this group. What we have is - if G is a finite simple group of Lie type with rank n, and its base field has bounded size, then the diameter of the Cayley graph C(G; S) would be bounded by exp(O(n(logn)^3)). If the size of the base field Fq is not bounded then our method gives a bound of q^(O(n(log nq)3)) for the diameter.In the third part we are interested in the growth of sets inside commutative Moufang loops which are commutative loops respecting the moufang identities but without (necessarily)being associative. For them we show that if the sizes of the associator sets are bounded then the growth of approximate substructures inside these loops is similar to those in ordinary groups. In this way for the subclass of finitely generated commutative moufang loops we have a classification theorem of its approximate subloops
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Davis, Aaron Charles, and aaron davis@rmit edu au. "Quantitative Characterisation of Airborne Electromagnetic Systems." RMIT University. Applied Physics, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080723.103030.
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I address the geometric problem of the pendulum-like swinging of towed birds for AEM platforms. I establish a link between actual observed bird swing and its effect on survey data for two different systems and explain the link by a model that compares actual survey data to the calculated mutual inductance coupling of a dipole pair over an infinitely conductive half space, which pair is permitted arbitrary pitch, roll and altitude changes. I develop a non-linear filter that removes bird swing effects from survey data which successfully corrected data from 3 different AEM surveys. Calibration of several different time domain AEM systems is attempted using an accurately laid out and surveyed, closed, multi-turn loop of known resistance and self-inductance that is placed on - but insulated from - resistive ground. I derive a rigourous mathematical model that predicts airborne receiver's response to the coupling to the transmitter current waveform and total system geometry. The method was proven to be successful over resistive ground, with significant system problems identified such as: altimetry error, spatial averaging of data during postprocessing, error in the predicted horizontal position of the AEM platform, receiver windowing and timing errors and bird swing. I show that, although we can calibrate a time domain AEM system for a single flyover, it is impossible to calibrate an AEM system for geometry. As an intermediate step in the calibration process, I show that by monitoring the current induced in the ground loop we can obtain the waveform of the AEM transmitter current throu gh deconvolution in the Fourier domain. Simple and cost effective methods for the improvement of quantitative AEM data are presented in this thesis. However, until the geometry problem of AEM platforms is solved, full system calibration will not be obtained and filters will need to be applied to the data. I recommend the use of: GPS antennas mounted on all towed birds, able to be post-processed for accurate position recovery, reliable bird-mounted scanning altimeters that do not rely on range-finding technology but instead employ a shortest path algorithm, pitch and roll sensors mounted on the trailed bird and the measurement of airspeed of both the towed bird and the aircraft during surveys.
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Gavira, Romero Alberto. "Cellular approximations of infinite loop spaces and classifying spaces." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/133278.
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Dado un espacio topológico punteado A, E. Dror-Farjoun introduce en 1995 la noción de A-homotopía, donde A y sus suspensiones juegan el mismo papel que las esferas en homotopía clásica. Por tanto se definen los grupos de A-homotopía de un espacio punteado X como las clases de homotopía de aplicaciones definidas desde las suspensiones de A a X. La idea de CW-complejo es sustituida por la de espacio A-celular, i.e., un espacio construido mediante ciertos colímites homotópicos punteados de A de manera iterada. El concepto de aproximación celular es remplazada por la de aproximación A-celular, esto es, un espacio A-celular CWAX junto con una aplicación natural CWAX → X que induce una equivalencia entre los espacios de aplicaciones punteadas map*(A, CWAX) y map*(A, X), y por tanto un isomorfismo en grupos de A-homotopía.
Sea p un número primo. En este trabajo estudiamos la A-celularización, donde A es un espacio clasificador del tipo BZ/pm, BZ/p∞ o un producto de estos, de dos familias de espacios: los espacios ΣBZ/p-acíclios salvo p-completación, y los espacios clasificadores de grupos p-locales compactos.
En el primer caso vemos que la A-celularización de un espacio ΣBZ/p-acíclio salvo p-completación 1-conexo X es equivalente a la fibra homotópica de la racionalización X^p → (X^p)Q. Como ejemplos tenemos los espacios de lazos infinitos y las torres de Postnikov 1-conexos con segundo grupo de homotopía de torsión.
En el segundo caso, dado un grupo p-local compacto (S, F , L ), para el estudio de la celularización de |L |^p definimos el núcleo de una aplicación f : |L |^p → Y^p como el subgrupo de S formado por los elementos x tales que la restricción de f al espacio clasificador del grupo generado por x es homotópicamente trivial. Demostramos que, bajo ciertas hipótesis sobre |L |^p, si el núcleo de cierta aplicación determinante en el cálculo de la celularización es todo el p-grupo S, entonces la A-celularización de |L |^p es equivalente a la fibra homotópica de la racionalización |L |^p → (|L |^p)Q . En el caso finito somos un más precisos, demostrando que si (S, F , L ) es un grupo p-local finito entonces |L |^p es BZ/pm -celular si y solamente si dicho núcleo es igual al mínimo subgrupo de S fuertemente cerrado que contiene toda la pi-torsión para i ≤ m. En el caso de un grupo de Lie compacto y conexo probamos que existe un entero no negativo m0 tal que para todo m ≥ m0 la (BZ/p∞ x BZ/pm)-celularización de BG^p es equivalente a la fibra homotópica de la racionalización BG^p → (BG^p)Q.Given a pointed topological space A, in 1995 E. Dror-Farjoun introduced the notion of A-homotopy, where A and its suspensions play the same role of the spheres in classical homotopy. Therefore the A-homotopy groups of a pointed space X are defined as the homotopy classes of maps from the suspensions of A to X. The idea of CW-complex is replaced by the one of A-cellular space, i.e., a space constructed by certain iterated homotopy colimits from A. The concept of cellular approximation is replaced by the A-cellular approximation, this is, a space A-cellular CWAX together with a natural map CWAX → X which induces an equivalence in the mapping spaces map*(A, CWAX) and map*(A, X), and hence an isomorphism in A-homotopy groups. Let p be a prime. In this work we study the A-cellularization, where A is a classifying space of type BZ/pm, BZ/p∞, or a product of these, of two families of spaces: the ΣBZ/p-acyclic spaces up to p-completion and the classifying spaces of p-local compact groups. In the first case we prove that the A-cellularization of a 1-connected ΣBZ/p-acyclic space up to p-completion X is equivalent to the homotopy fibre of the rationalization X^p → (X^p)Q.. Examples include the 1-connected infinite loop spaces and Postnikov pieces whose second homotopy group is a torsion group. In the second case, given a p-local group compact (S, F , L ), for the study of the A-cellularization of |L |^p, we define the kernel of a map f : |L |^p → Y^ as the subgroup of S formed by the elements x which the restriction of f to the classifying space of the group generated by x is null-homotopic. Under certain assumptions on |L |^p, we show that if the kernel of a certain map, which is determinant in the computation of the A-cellularization, is the p-group S, then the A-cellularization of |L |^p is the homotopy fibre of the rationalization |L |^p → (|L |^p)Q. In the finite case we are more precise, we prove that if (S, F , L ) is a finite p- local group, then |L |^p is BZ/pm-cellular if and only if the kernel of this map is equal to the minimal strongly F -closed subgroup in S that contains all the pi-torsion for i ≤ m. In the case of a compact Lie group, we prove that there is a non-negative integer m0 such that for all m ≥ m0, the (BZ/p∞ x BZ/pm)-cellularization of BG^p is equivalent to the homotopy fibre of the rationalization BG^p → (BG^p)Q.
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Takata, Doman. "A Loop Group Equivariant Analytic Index Theory for Infinite-dimensional Manifolds." Kyoto University, 2018. http://hdl.handle.net/2433/232217.
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Helmreich, Peter [Verfasser], Karl-Hermann [Akademischer Betreuer] Neeb, and Karl-Hermann [Gutachter] Neeb. "A Convexity Theorem for Twisted Loop Groups / Peter Helmreich ; Gutachter: Karl-Hermann Neeb ; Betreuer: Karl-Hermann Neeb." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2020. http://d-nb.info/1223708233/34.
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Mukai, Daichi. "Mirror symmetry of nonabelian Landau-Ginzburg orbifolds with loop type potentials." Kyoto University, 2020. http://hdl.handle.net/2433/253068.
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Billings, Don, Mei Wei, Joseph Leung, Michio Aoyagi, Fred Shigemoto, and Rob Honeyman. "REAL-TIME INTEGRATION OF RADAR INFORMATION, AND GROUND AND RADIOSONDE METEOROLOGY WITH FLIGHT RESEARCH DATA." International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/607368.
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International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, CaliforniaAlthough PCM/TDM framed data is one of the most prevalent formats handled by flight test ranges, it is often required to acquire and process other types. Examples of such non-standard data types are radar position information and meteorological data from both ground based and radiosonde systems. To facilitate the process and management of such non-standard data types, a micro-processor based system was developed to acquire and transform them into a standard PCM/TDM data frame. This obviated the expense of developing additional special software and hardware to handle such non-standard data types.
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Renard, Sylvain. "Validation «Hardware in the loop » de l’architecture de commande embarquée du groupe moto-propulseur hybride pour véhicules industriels." Lyon, INSA, 2008. http://theses.insa-lyon.fr/publication/2008ISAL0131/these.pdf.
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[Le développement de véhicules de moins en moins polluants entraine une complexification des architectures électroniques embarquées liées au groupe motopropulseur ce qui accroît le risque de panne. L’objectif de nos travaux est de développer une plateforme de simulation HIL (Hardware In the Loop) permettant de vérifier la conformité des calculateurs embarqués associés à un véhicule industriel hybride de configuration parallèle, vis-à-vis de leurs spécifications. A partir de l’analyse des plans de vérification, nous avons défini une démarche de construction de cette plateforme, le but étant de définir le périmètre nécessaire et le type de modélisation requis pour couvrir l’ensemble des tests. Une attention particulière a été apportée dans la construction des modèles de la machine électrique, du convertisseur DC/AC ou de la boîte de vitesses par l’intermédiaire du langage bond-graph. L’efficacité de cette démarche a pu être démontrée par la réalisation effective des plans de vérification. ][The development of vehicles less polluting leads to more complex electronic architectures related to the powertrain, which increases the risk of failure. The main objective of our work is to develop a HIL (Hardware In the Loop) simulation platform in order to verify the electronic system compliance, in charge of a parallel hybrid powertrain management, in relation to its specifications. From verification plans analysis, we have defined a method to build a specification booklet for the HIL platform development; the aim was to define the necessary area and the type of the required modelling to cover the complete verification plan. A special care has been brought in the development of the models of electrical machine, DC/AC converter or gearbox with the help of bond graph language. The efficiency of this method has been proved with the effective achievement of ECU verification plans. . ]
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Inahama, Yuzuru. "Logarithmic Sobolev Inequality on Free Loop Groups for Heat Ker-nel Measures Associated with the General Sobolev Spaces." 京都大学 (Kyoto University), 2001. http://hdl.handle.net/2433/150808.
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Pranzetti, Daniele. "TQFT and Loop Quantum Gravity : 2+1 Theory and Black Hole Entropy." Thesis, Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10032.
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Ce travail de thèse se concentre sur l'approche non-perturbative canonique à la formulation d'une théorie quantique de la gravitation dans le cadre de la Gravitation quantique à boucles (LQG), répondant à deux problèmes majeurs. Dans la première partie, nous étudions la possible quantification, dans le cadre de la LQG, de la gravité en trois dimensions avec constante cosmologique et nous essayons de prendre contact avec autres approches de quantification déjà existantes dans la littérature. Dans la deuxième partie, nous nous concentrons sur une application très importante de la LQG: la définition et le comptage des états microscopiques d'un ensemble en mécanique statistique qui fournit une description de l'entropie des trous noirs. Notre analyse s'appuie fortement sur et s'étend à un traitement manifestement SU(2) invariant les travaux fondateurs de Ashtekar et alThis thesis work concentrates on the non-perturbative canonical approach to the formulation of a quantum theory of gravity in the framework of Loop Quantum Gravity (LQG), addressing two major problems. In the first part, we investigate the possible quantization, in the context of LQG, of three dimensional gravity in the case of non-vanishing cosmological constant and try to make contact with alternative quantization approaches already existing in the literature. In the second part, we concentrate on a very important application of LQG: the definition and the counting of microstates of a statistical mechanical ensemble which provides a description and accounts for the black hole entropy. Our analysis strongly relies on and extends to a manifestly SU(2) invariant treatment the seminal work of Ashtekar et al
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Wuttke, Sebastian. "Some aspects of the Wilson loop." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2015. http://dx.doi.org/10.18452/17225.
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Diese Arbeit wird durch die AdS/CFT Korrespondenz, sowie durch die Dualität zwischen lichtartigen, polygonalen Wilsonschleifen und Gluonenstreuamplituden in N=4 Super-Yang-Mills-Theorie motiviert. Bei starker Kopplung haben lichtartige, polygonale Wilsonschleifen und Gluonenstreuamplituden eine Beschreibung über raumartige Minimalflächen in AdS5. Wir benutzen eine Pohlmeyerreduktion, um eine Klassifikation aller raumartigen Minimalflächen in AdS3xS3 mit flachen Projektionen herzuleiten. Diese Klassifikation enthält neun verschiedene Klassen von Flächen. Dabei treten raumartige, zeitartige und degenerierte AdS3-Projektionen auf. Bei denjenigen Lösungen, die einen geschlossenen, polygonalen und lichtartigen Rand besitzen, berechnen wir den regularisierten Flächeninhalt. Bei schwacher Kopplung erfüllen lichtartige, polygonale Wilsonschleifen und Gluonenstreuamplituden den um eine Remainderfunktion korrigierten BDS-Ansatz. Wir präsentieren eine Technik, die auf einer Renormierungsgruppengleichung für selbstschneidende Wilsonschleifen beruht, mit der wir die Divergenzen der Remainderfunktion in diesem Limes berechnen können. Mittels dieser Technik analysieren wir zwei Arten des Selbstschnittes. Im Falle des Selbstschnittes zwischen zwei Ecken berechnen wir die führenden Divergenzen bis zur vierten Schleifenordnung. Beim Selbstschnitt zwischen zwei Kanten berechnen wir die führenden und nächstfolgenden Divergenzen bis zur vierten Schleifenordnung und präsentieren eine analytische Fortsetzung in die Region der Euklidischen Wilsonschleifen und sagen bestimmte Terme vorher, die in dem unbekannten analytischen Ausdruck für die Remainderfunktion enthalten sein müssen.This thesis is motivated by the AdS/CFT correspondence and the duality between gluon scattering amplitudes and light-like polygonal Wilson loops in N=4 super Yang-Mills theory. At strong coupling light-like polygonal Wilson loops and gluon scattering amplitudes have a description in terms of space-like minimal surfaces in AdS5. We use a Pohlmeyer reduction to derive a classification of all space-like minimal surfaces in AdS3xS3 that have flat projections. The classification consists of nine different classes and contains space-like, time-like and degenerated AdS3 projections. For solutions that admit a closed light-like polygonal boundary we calculate the regularized area. At weak coupling light-like polygonal Wilson loops and gluon scattering amplitudes obey the BDS Ansatz corrected by a remainder function. We present a renormalisation group equation technique using self-crossing Wilson loops to extract the divergences of the remainder function in this limit. Using this technique we analyse two different types of self-crossing. We present the leading and sub-leading divergences up to four loops for a crossing between two edges and the leading divergences for a crossing between two vertices. For a crossing between two edges we present an analytic continuation to the euclidean regime to predict certain terms that have to occur in the unknown analytic expression of the remainder function.
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Rappel, Valentin Maximilian [Verfasser], Peter [Gutachter] Littelmann, and Ghislain [Gutachter] Fourier. "The path model and Bott–Samelson manifolds in the context of loop groups / Valentin Maximilian Rappel ; Gutachter: Peter Littelmann, Ghislain Fourier." Köln : Universitäts- und Stadtbibliothek Köln, 2021. http://d-nb.info/1230059881/34.
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Lano, Ralph Peter. "Application of co-adjoint orbits to the loop group and the diffeomorphism group of the circle." Thesis, University of Iowa, 1994. https://ir.uiowa.edu/etd/5393.
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Kufa, Martin. "Planární fraktální filtr na substrátu s porušenou zemí." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219832.
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The diploma thesis is focused on the design of planar filters combining fractal layouts and defected ground substrates. The diploma thesis can be divided into three main parts. First, basic knowledge about fractals is presented (creation of Minkowski Island and Koch loop, e.g.). Then, the principle of defected ground structure is described, and a combination of fractal motives with a defected ground structure is briefly introduced. Properties of investigated structures are verified by CST Microwave Studio and Ansoft HFSS. Second, different defected ground structures under the 50 transmission line are designed, and conventional equivalent filters are created. Filters are simulated and compared. In final, the investigated filters are recalculated for the substrate Arlon 25N, simulated, manufactured, measured and confronted with a conventional filter on the defected ground substrate.
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Abbas, Junaid. "Logical selectivity for medium voltage overcurrent protection and its verification via co-simulation tool for the responses of the power and communication network." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15274/.
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This thesis deals with the modelling and simulation of MV network overcurrent protection using EMTP. Transmission lines 25 Km in length for both radial and loop network with constant parameters operates at 50 Hz and 66 kV line to line voltages are simulated using EMTP. The first part of the thesis discusses the simulation of Radial network with unearthed neutral for analysing the behaviour of the fault current making the comparison with healthy feeder. Second part is to use a Radial network with compensated neutral, Petersen Coil (PC) is used for compensation of the short circuit current making the similar comparison. Third step is to design a 67N directional replay protection in EMTP to trip the circuit breaker in the fault situation. Then using both Radial and Loop network, a comparison and response of the 67N protection in both situations is analysed. Several simulations of Single Line to Ground Faults (SLGF) with different fault locations were carried out to verify the correct operation of the relay based on the developed protection scheme. The results of the simulation the operation of the relay based on its protection scheme and its response time based on the fault location. Finally, delay between the blocking signals are inserted to see the behaviour of the protection system under loop network configuration.
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Young, Nathan Lee. "Effect of Rivers on Groundwater Temperature in Heterogeneous Buried-Valley Aquifers: Extent, Attenuation, and Phase Lag of Seasonal Variation." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401813367.
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Aldubyan, Mohammad Hasan. "Thermo-Economic Study of Hybrid Photovoltaic-Thermal (PVT) Solar Collectors Combined with Borehole Thermal Energy Storage Systems." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1493243575479443.
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Pellegrino, Gregory S. "Design of a Low-Cost Data Acquisition System for Rotordynamic Data Collection." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/1978.
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A data acquisition system (DAQ) was designed based on the use of a STM32 microcontroller. Its purpose is to provide a transparent and low-cost alternative to commercially available DAQs, providing educators a means to teach students about the process through which data are collected as well as the uses of collected data. The DAQ was designed to collect data from rotating machinery spinning at a speed up to 10,000 RPM and send this data to a computer through a USB 2.0 full-speed connection. Multitasking code was written for the DAQ to allow for data to be simultaneously collected and transferred over USB. Additionally, a console application was created to control the DAQ and read data, and MATLAB code written to analyze the data. The DAQ was compared against a custom assembled National Instruments CompactDAQ system. Using a Bentley-Nevada RK 4 Rotor Kit, data was simultaneously collected using both DAQs. Analysis of this data shows the capabilities and limitations of the low cost DAQ compared to the custom CompactDAQ.
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Lumia, Luca. "Digital quantum simulations of Yang-Mills lattice gauge theories." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/22355/.
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I metodi di calcolo tradizionali per le teorie di gauge su reticolo risultano problematici in regioni di diagrammi di fase a grandi valori del potenziale chimico o quando sono utilizzate per riprodurre la dinamica in tempo reale di un modello. Tali problemi possono essere evitati da simulazioni quantistiche delle teorie di gauge su reticolo, le quali stanno diventando sempre più riproducibili sperimentalmente, grazie ai recenti progressi tecnologici. In questa tesi formuliamo una versione delle teorie di Yang-Mills su reticolo appropriata per risolvere il problema della dimensione infinita dello spazio di Hilbert associato ai bosoni di gauge. Questa formulazione è adatta per essere riprodotta in un simulatore quantistico e ne implementiamo una completa simulazione su un computer quantistico digitale, sfruttando il framework Qiskit. In questa simulazione misuriamo le energie del ground state e i valori di aspettazione di alcuni Wilson loop al variare dell'accoppiamento della teoria, per studiarne le fasi e valutare la prestazione dei metodi usati.
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Pettersson, Anna, and Anna Larsson. ""There is no business on a dead planet" : En fallstudie av interna kommunikationsprocesser om hållbara arbetssätt i IT-konsultbranschen." Thesis, Uppsala universitet, Institutionen för informatik och media, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-416775.
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Sustainability has become increasingly important in global debates and in world politics, where the UN has formulated 17 sustainability goals. This has led to increased pressure on companies to focus more on sustainability. However, sustainability is a broad and difficult concept, where there is a lack of understanding of sustainable working methods. The purpose of the thesis is thus to study how companies transforms strategic approaches into something concrete and how it is communicated to organizations. Through a case study of a sustainability-leading IT consulting company, the research questions; "How does management translate sustainable strategies into concrete initiatives for communicating sustainable approaches?" and "What can be understood about the challenges of communicating sustainable ways of working through the organisations internal communicative processes?", is being answered. Based on the theoretical framework of the thesis, on Sensemaking and Double Loop Learning, the communication process has been mapped within the company, through semi-structured interviews supplemented with qualitative document analysis. The results show three main challenges: (1) to concrete sustainability and sustainable working methods; (2) to communicate and establish a unified understanding of sustainability and sustainable working practices throughout the organization; (3) to establish systems thinking for sustainable working methods.
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Carrozza, Sylvain. "Tensorial methods and renormalization in Group Field Theories." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112147/document.
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Cette thèse présente une étude détaillée de la structure de théories appelées GFT ("Group Field Theory" en anglais),à travers le prisme de la renormalisation. Ce sont des théories des champs issues de divers travaux en gravité quantique, parmi lesquels la gravité quantique à boucles et les modèles de matrices ou de tenseurs. Elles sont interprétées comme desmodèles d'espaces-temps quantiques, dans le sens où elles génèrent des amplitudes de Feynman indexées par des triangulations,qui interpolent les états spatiaux de la gravité quantique à boucles. Afin d'établir ces modèles comme des théories deschamps rigoureusement définies, puis de comprendre leurs conséquences dans l'infrarouge, il est primordial de comprendre leur renormalisation. C'est à cette tâche que cette thèse s'attèle, grâce à des méthodes tensorielles développées récemment,et dans deux directions complémentaires. Premièrement, de nouveaux résultats sur l'expansion asymptotique (en le cut-off) des modèles colorés de Boulatov-Ooguri sont démontrés, donnant accès à un régime non-perturbatif dans lequel une infinité de degrés de liberté contribue. Secondement, un formalisme général pour la renormalisation des GFTs dites tensorielles (TGFTs) et avec invariance de jauge est mis au point. Parmi ces théories, une TGFT en trois dimensions et basée sur le groupe de jauge SU(2) se révèle être juste renormalisable, ce qui ouvre la voie à l'application de ce formalisme à la gravité quantiqueIn this thesis, we study the structure of Group Field Theories (GFTs) from the point of view of renormalization theory.Such quantum field theories are found in approaches to quantum gravity related to Loop Quantum Gravity (LQG) on the one hand,and to matrix models and tensor models on the other hand. They model quantum space-time, in the sense that their Feynman amplitudes label triangulations, which can be understood as transition amplitudes between LQG spin network states. The question of renormalizability is crucial if one wants to establish interesting GFTs as well-defined (perturbative) quantum field theories, and in a second step connect them to known infrared gravitational physics. Relying on recently developed tensorial tools, this thesis explores the GFT formalism in two complementary directions. First, new results on the large cut-off expansion of the colored Boulatov-Ooguri models allow to explore further a non-perturbative regime in which infinitely many degrees of freedom contribute. The second set of results provide a new rigorous framework for the renormalization of so-called Tensorial GFTs (TGFTs) with gauge invariance condition. In particular, a non-trivial 3d TGFT with gauge group SU(2) is proven just-renormalizable at the perturbative level, hence opening the way to applications of the formalism to (3d Euclidean) quantum gravity
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Olsen, Peter A. "Shear Modulus Degradation of Liquefying Sand: Quantification and Modeling." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/1214.
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A major concern for geotechnical engineers is the ability to predict how a soil will react to large ground motions produced by earthquakes. Of all the different types of soil, liquefiable soils present some of the greatest challenges. The ability to quantify the degradation of a soil's shear modulus as it undergoes liquefaction would help engineers design more reliably and economically. This thesis uses ground motions recorded by an array of downhole accelerometers on Port Island, Japan, during the 1995 Kobe Earthquake, to quantify the shear modulus of sand as it liquefies. It has been shown that the shear modulus of sand decreases significantly as it liquefies, apparently decreasing in proportion to the increasing excess pore water pressure ratio (Ru). When completely liquefied, the shear modulus of sand (Ru = 1.0) for a relative density of 40 to 50% is approximately 15% of the high-strain modulus of the sand in its non-liquefied state, or 1% of its initial low-strain value. Presented in this thesis is an approach to modeling the shear modulus degradation of sand as it liquefies. This approach, called the "degrading shear modulus backbone curve method" reasonably predicts the hysteretic shear stress behavior of the liquefied sand. The shear stresses and ground accelerations computed using this method reasonably matches those recorded at the Port Island Downhole Array (PIDA) site. The degrading shear modulus backbone method is recommended as a possible method for conducting ground response analyses at sites with potentially liquefiable soils.
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Thürigen, Johannes. "Discrete quantum geometries and their effective dimension." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2015. http://dx.doi.org/10.18452/17309.
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In einigen Ansätzen zu einer Quantentheorie der Gravitation wie Gruppenfeldtheorie und Schleifenquantengravitation zeigt sich, dass Zustände und Entwicklungen der geometrischen Freiheitsgrade auf einer diskreten Raumzeit basieren. Die dringendste Frage ist dann, wie die glatten Geometrien der Allgemeinen Relativitätstheorie, beschrieben durch geeignete geometrische Beobachtungsgrößen, aus solch diskreten Quantengeometrien im semiklassischen und Kontinuums-Limes hervorgehen. Hier nehme ich die Frage geeigneter Beobachtungsgrößen mit Fokus auf die effektive Dimension der Quantengeometrien in Angriff. Dazu gebe ich eine rein kombinatorische Beschreibung der zugrunde liegenden diskreten Strukturen. Als Nebenthema erlaubt dies eine Erweiterung der Gruppenfeldtheorie, so dass diese den kombinatorisch größeren kinematischen Zustandsraum der Schleifenquantengravitation abdeckt. Zudem führe ich einen diskreten Differentialrechnungskalkül für Felder auf solch fundamental diskreten Geometrien mit einem speziellen Augenmerk auf dem Laplace-Operator ein. Dies ermöglicht die Definition der Dimensionsobservablen für Quantengeometrien. Die Untersuchung verschiedener Klassen von Quantengeometrien zeigt allgemein, dass die spektrale Dimension stärker von der zugrunde liegenden kombinatorischen Struktur als von den Details der zusätzlichen geometrischen Daten darauf abhängt. Semiklassische Zustände in Schleifenquantengravitation approximieren die entsprechenden klassischen Geometrien gut ohne Anzeichen für stärkere Quanteneffekte. Dagegen zeigt sich im Kontext eines allgemeineren, auf analytischen Lösungen basierenden Modells für Zustände, die aus Überlagerungen einer großen Anzahl von Komplexen bestehen, ein Fluss der spektralen Dimension von der topologischen Dimension d bei kleinen Energieskalen hin zu einem reellen Wert zwischen 0 und d bei hohen Energien. Im Spezialfall 1 erlauben diese Resultate, die Quantengeometrie als effektiv fraktal aufzufassen.In several approaches towards a quantum theory of gravity, such as group field theory and loop quantum gravity, quantum states and histories of the geometric degrees of freedom turn out to be based on discrete spacetime. The most pressing issue is then how the smooth geometries of general relativity, expressed in terms of suitable geometric observables, arise from such discrete quantum geometries in some semiclassical and continuum limit. In this thesis I tackle the question of suitable observables focusing on the effective dimension of discrete quantum geometries. For this purpose I give a purely combinatorial description of the discrete structures which these geometries have support on. As a side topic, this allows to present an extension of group field theory to cover the combinatorially larger kinematical state space of loop quantum gravity. Moreover, I introduce a discrete calculus for fields on such fundamentally discrete geometries with a particular focus on the Laplacian. This permits to define the effective-dimension observables for quantum geometries. Analysing various classes of quantum geometries, I find as a general result that the spectral dimension is more sensitive to the underlying combinatorial structure than to the details of the additional geometric data thereon. Semiclassical states in loop quantum gravity approximate the classical geometries they are peaking on rather well and there are no indications for stronger quantum effects. On the other hand, in the context of a more general model of states which are superposition over a large number of complexes, based on analytic solutions, there is a flow of the spectral dimension from the topological dimension d on low energy scales to a real number between 0 and d on high energy scales. In the particular case of 1 these results allow to understand the quantum geometry as effectively fractal.