Dissertations / Theses on the topic 'Stripe domains'

In this study, the formation of stripe domains in permalloy (NisoFe20) thin films was investigated mainly utilizing magnetic force microscopy. Stripe domains are a known phenomenon, which reduces the "softness" of magnetic material and introduces a significant source of noise when used in perpendicular magnetic media. For the particular setup mentioned in this report, a critical thickness for stripe domains initiation depended on the sputtering rate, the substrate temperature, and the film thickness. Beyond the stripe domain formation, an increase in the periodicity of highly ordered stripe domains was evident with increasing film thickness. Above a particular thickness, stripe domains periodicity decreased along with magnetic domain randomization. The results led to the inference that the perpendicular anisotropy responsible for the formation of stripe domains originated mainly from magnetostriction.

Les phases alpha'-Fe8N1-x et alpha''-Fe16N2 ont un fort potentiel d’application, en raison de leur anisotropie magnétocristalline uniaxiale et de leur grande aimantation à saturation. Cependant, les valeurs annoncées pour ces propriétés magnétiques restent sujettes à discussion. Les recherches menées au cours de cette thèse de doctorat ont été initiées dans le but de clarifier cette situation. L’élaboration des échantillons a principalement consisté en l’implantation ionique d’azote dans des couches minces de fer alpha épitaxiées sur ZnSe/GaAs (001). Entre autres, les effets de la température de la cible et de la fluence sur la structure cristalline des échantillons ont été analysés par diffractométrie des rayons X. La présence d’une anisotropie magnétique perpendiculaire a été mise en évidence dans les couches minces contenant les phases alpha'-Fe8N1-x ou alpha''-Fe16N2. La constante d’anisotropie a été évaluée par magnétométrie à échantillon vibrant et résonance ferromagnétique. À l’occasion de ces recherches, des domaines en rubans faibles ont été observés par microscopie à force magnétique dans certaines couches minces en Fe-N. Ceux-ci sont particulièrement rectilignes et des dislocations coin se trouvent au sein de leur structure périodique. Des études ont alors été réalisées dans le but de contrôler avec précision la réorientation des domaines en rubans et le déplacement des dislocations magnétiques, à l’aide d’un champ magnétique
The alpha'-Fe8N1-x and alpha''-Fe16N2 phases have a high potential of application, because of their uniaxial magnetocrystalline anisotropy and their large saturation magnetization. However, the values announced for these magnetic properties remain a subject of discussion. The research conducted during this PhD thesis was initiated in order to clarify this situation. Sample making consisted mainly of nitrogen ion implantation into alpha-Fe thin films, epitaxially grown on ZnSe/GaAs (001). Among others, the effects of target temperature and fluence on the crystal structure of the samples were analyzed by X-ray diffractometry. The presence of a perpendicular magnetic anisotropy was demonstrated in the thin films containing the alpha'-Fe8N1-x and alpha''-Fe16N2 phases. The anisotropy constant was evaluated by vibrating sample magnetometry and ferromagnetic resonance. In this research, weak stripe domains were observed by magnetic force microscopy in some Fe-N thin films. These are particularly straight and edge dislocations are found within their periodic structure. Studies were then carried out to precisely control the reorientation of the stripe domains and the displacement of the magnetic dislocations, using a magnetic field

Des distributions inhomogènes de l’aimantation existent lorsque le matériau n’est pas uniforme, ou lorsqu’une texture magnétique se forme dans un matériau homogène. Dans les deux cas, les symétries brisées modifient l’excitation et la propagation des ondes de spin et donnent lieu à des phénomènes surprenants. Dans ce contexte, nous avons étudié la propagation des ondes de spin dans une bicouche avec un contraste de l’aimantation de saturation dans la configuration Damon-Eshbach. Nous avons trouvé, à l’aide de simulations et expériences (spectroscopie d'ondes de spin propagatives et diffusion de Brouillon), que le système montre une très forte non-réciprocité en fréquence qui peut être utilisée pour réaliser une diode magnonique. Par ailleurs, nous avons étudié la dynamique des ondes de spin dans des couches minces qui présentent des domaines magnétiques en rubans faibles. Nous avons montré que ces ondes de spin peuvent être interprétées comme une extension des modes de Damon-Eshbach dans l’état saturé, qui s’adaptent à la brisure de symétrie. Nous avons également montré que les deux modes d’ondes de spin de plus basse fréquence correspondent aux modes de Goldstone et Higgs de la texture en rubans. Ces résultats ont été confirmés par des mesures de diffusion Brillouin et de résonance ferromagnétique
Inhomogeneous magnetization distributions may exist because the magnetic parameters are distributed, or because magnetic textures nucleate in homogenous materials. In both cases, the broken symmetries affect the spin-wave excitation and propagation, leading to a number of intriguing phenomena. In this context, we have studied the propagation of spin waves in a bilayer with a saturation magnetization contrast for the Damon-Eshbach configuration. We have found, by means of simulations and experiments (Propagating Spin Wave Spectroscopy and Brillouin Light Scattering), that this system shows a strong frequency non-reciprocity which can be used for the realization of a spin-wave diode. We have also studied the spin-wave dynamics in thin films which exhibit weak magnetic stripe domains. We have shown how these modes can be interpreted as an extension of the Damon-Eshbach spectrum of the saturated state, which adapts to the symmetry breaking. Furthermore, we have identified the two lowest frequency modes to the Goldstone- and Higgs- modes of the stripe texture. These results were confirmed by Brillouin Light Scattering and Ferromagnetic Resonance experiments

The domain decomposition strategies proposed in this thesis are efficient preconditioning techniques with good parallelism properties for the discrete systems which arise from the finite element approximation of symmetric elliptic boundary value problems in two and three-dimensional Euclidean spaces. For two-dimensional problems, two new domain decomposition preconditioners are introduced, such that the condition number of the preconditioned system is bounded independently of the size of the subdomains and the finite element mesh size. First, the alternate strip-based (ASB2) preconditioner is based on the partitioning of the domain into a finite number of nonoverlapping strips without interior vertices. This preconditioner is obtained from direct solvers inside the strips and a direct fast Poisson solver on the edges between strips, and contains two stages. At each stage the strips change such that the edges between strips at one stage are perpendicular on the edges between strips at the other stage. Next, the alternate strip-based substructuring (ASBS2) preconditioner is a Schur complement solver for the case of a decomposition with multiple nonoverlapping subdomains and interior vertices. The subdomains are assembled into nonoverlapping strips such that the vertices of the strips are on the boundary of the given domain, the edges between strips align with the edges of the subdomains and their union contains all of the interior vertices of the initial decomposition. This preconditioner is produced from direct fast Poisson solvers on the edges between strips and the edges between subdo- mains inside strips, and also contains two stages such that the edges between strips at one stage are perpendicular on the edges between strips at the other stage. The extension to three-dimensional problems is via solvers on slices of the domain.

The finite strip method (FSM) is a very efficient numerical method employed for performing the structural analysis of slender structures, such as cable-stayed bridges; the strip discretization of the model allows for the usage of a lower number of degrees of freedom, in comparison with the finite element method (FEM), while, as it will be discussed in the current research, the results obtained from both methods are in relatively good agreement. Moreover, to address the latest developments in the area of smart construction materials used for long-span bridges, the fiber reinforced polymer (FRP) composites were implemented for the bridge deck modeling, as part of a hybrid composite FRP cable-stayed bridge, and an extend laminate integrated finite strip method (LFSM) was applied for estimating the static structural performance of the hybrid composite FRP long-span cable-stayed bridge under several concentrated and uniformly distributed loadings. The free vibrations analysis was conducted for the Kap Shui Mun Cable-stayed Bridge model, and the natural frequencies were compared with the ones obtained from an FE model of the same bridge. One of the advantages of using the integrated finite strip method is that number of vibration modes, which can be included in the dynamic analysis when the effect of a sweeping sinus and a seismic loading are investigated when a conventional FE analysis would fail to converge. The outcomes of this research will set the stage for the hybrid long-span cable-stayed bridges modeling by the laminate integrated finite strip method (LFSM) which is more efficient and straightforward than the finite element analysis, for performing the static, free vibration, time domain, and frequency domain analyses.

Thesis (S.M. in Naval Architecture and Marine Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 87-88).
Seakeeping analysis of the Zumwalt-Class destroyer was carried out in the framework of linear strip theory and potential flow. First, the problem was formulated and solved analytically. Second, a program called Ship Motions Analyzer (SMA) was written in MATLABTM to carry out the seakeeping analysis for regular waves in a discretized frequency range. SMA calculates sectional added mass and damping coefficients first. Then, it calculates excitation forces and moments acting on a ship advancing at constant forward speed with arbitrary heading for sway, heave, roll, pitch and yaw modes of motion. Finally, SMA evaluates Response Amplitude Operators (RAO's) in the same modes of motion. In addition, it also includes a subroutine which evaluates steady drift forces acting on a ship in the plane of undisturbed free surface. The added mass and damping coefficients of a fully submerged heaving circle and a semi-circle in heave and sway were calculated to validate the results of SMA. The results were compared to the results of Vugst [1] and Frank [2]. They match each other exactly. In addition, the magnitudes of heave and pitch excitation force and moment, and RAO's in the same modes of motions were calculated. The results agree with the theory. Finally, added resistance of Mariner type ship was calculated by SMA to compare the results to the ones given by Salvasen [3] and to validate the calculations. These results are also in very good agreement with the available computational and experimental results.
by Ilkay Ozer Erselcan.
S.M.in Naval Architecture and Marine Engineering

This paper outlines the theory, development, validation, and some results of a quadratic strip theory method to predict the global structural response of the KRISO hull geometry due to regular waves in the time-domain. The method attempts to capture nonlinear effects of the dynamic problem due to time-varying underwater hull volume imparted by waves and vessel motions. These effects are formulated by drawing a relationship between the coefficients, 𝐴33, 𝐵33, and 𝐶33 and the sectional draft, 𝑇𝑠. Additional nonlinearities are introduced by allowing for a flexible hull girder, and the inclusion of structural damping. Validation is facilitated by running test computations and comparing the linear and nonlinear results to segmented model test data. It is found that the predicted results are validated by the model data, and that nonlinear effects account for a significant increase in predicted bending moment.

Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Tentzeris, Emmanouil; Committee Member: Andrew Peterson; Committee Member: Laskar, Joy; Committee Member: Papapolymerou, Ioannis. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Le gisement de Tocantinzinho est situé sur la province aurifère de Tapajós et est le plus grand gisement d'or de la province, avec 53,9 tonnes d'or estimées. Sa formation commence par un magmatisme granodioritique autour de 2005 Ma, suivi d'un magmatisme granitique. Le granite Tocantinzinho est composé de deux faciès principaux (syenogranite - 1996± 2Ma; monzogranite 1989±1 Ma), des corps d’aplite et de pegmatite, qui suggère un magmatisme enrichie en fluide et mis en place à faible profondeur. Intrusifs dans ces roches, des dykes d'andésite (1998±8Ma) ont des fragments de granite et des mélanges entre les 2 magmas suggèrent un magmatisme à la fois continu et polyphasé. Il est proposé que les premiers dykes d’andésite se sont mis en place alors que le granite n’était pas entièrement cristallisé (mingling) et les derniers lors des stades de déformation à l’état solide du granite. Utilisant la courbe de refroidissement, un âge minimum de 1975 Ma a été estimé pour l’andésite. Les taux de refroidissement des roches plutoniques varient de 3,6 à 14,7°C/Ma, avec une moyenne de 7,5°C/Ma, suggérant que les processus d'exhumation verticale sont faibles. La géométrie allongée du granite ainsi que la tectonique syn-magmatique de l'andésite corroborent la prédominance des mouvements horizontaux. L’affinité calc-alcaline fortement potassique et des anomalies en niobium définissent deux configurations possibles pour le cadre géotectonique: arc continental de type Andin ou Post-collisionnel. Compte tenue la relation génétique entre magmatisme, cisaillement décrochant et les faibles taux de refroidissement, l’environnement post-collisionnel est plus probable. Cela ensemble avec les âges nous permettent de comparer ces roches avec celles de la Suite Intrusive Creporizão (1997-1957Ma). La dacite (1992 ± 2 Ma) recoupe les autres roches, cependant, la signature géochimique comparable aux roches anorogéniques suggère qu’elle appartient à une série magmatique distinct. La zone minéralisée est limitée par deux failles majeures senestres de direction N100°-130E°. Le granite Tocantinzinho et les roches hypo-volcaniques déformées sont dans ce couloir, altérées par de fluides hydrothermaux et minéralisées pendant deux phases tectoniques distinctes. La première est caractérisée par des brèches et des microfractures remplies par muscovite (1864±5Ma) et pyrite, associées à de faibles teneur d’or (<1,5ppm) restreintes au granite. La deuxième phase a été contrôlée par le cisaillement décrochant senestre normal générant des fentes de tension et des brèches remplies par quartz, chlorite, calcite, albite, rutile, pyrite, galène, sphalérite, chalcopyrite et or. La teneur en or peut atteindre jusqu'à 70 ppm dans les veines riches en sulfures. Ces structures de remplissage syntectonique sont parallèles entre elles et orientées N30-60°E. Deux hypothèses ont été proposées pour expliquer la genèse du gisement: la première considère une relation génétique entre magmatisme et minéralisation au moins pour le premier stage de minéralisation selon un modèle porphyrique et la seconde alternative considère une réactivation des failles préexistantes par une tectonique transtensive liée au magmatisme Maloquinha (ca. 1880Ma) pour les deux stades minéralisateurs. Les deux phases dans les deux hypothèses, ont été classées comme des minéralisations de type magmato-hydrothermale qui pourraient être classées soit comme des systèmes d'or liés à l'intrusion. De nouveaux travaux sur le terrain et en laboratoire seraient nécessaires pour identifier et caractériser la nature et la source des fluides hydrothermaux, pour dater la minéralisation et mieux comprendre le rôle des roches hypo-volcaniques. Toutefois, les premiers résultats, et notamment le rôle fondamental du contrôle tectonique pour la minéralisation sont très significatifs et peuvent aider de manière conséquente à l'établissement des programmes d'exploration et d'exploitation futurs
The Tocantinzinho deposit is located on the Tapajós Gold Province and is the largest gold deposit within Province, with 53,9 tons of gold. Its formation begins with a granodioritic magmatism around 2005Ma, followed by a granitic magmatism 10 Ma latter. The Tocantinzinho granite is composed by two main facies, syenogranite (1996±2Ma) and monzogranite (1989±1Ma), and by aplite and pegmatite bodies, suggesting a fluid-rich magmatism at shallow depth. Andesite dikes (1998±8Ma) are intrusive in both rocks. Sharp fragments of those rocks along contacts and minor mingling with granitic magma suggest a multiphase magmatism at distinct timing. The first dikes have intruded within granite when it was crystalizing, thus a minimum age of 1975Ma was estimated. Cooling rates of plutonic rocks vary from 3.6 to 14.7°C/Ma, with an average of 7.5°C/Ma, suggesting vertical exhumation processes were minor. The elongated geometry of granite along with sin-magmatic strike-slip tectonics of andesite corroborate the predominance of horizontal movements. Geochemical analysis show high-K calk-alkaline affinity and niobium anomaly indicator of two possible geotectonic settings for these rocks: Andean-type continental arc or post-collisional one. Considering the genetic relationship between magmatism, strike-slip faults, and low cooling rates, a post-collisional setting is more likely. The geochemical signature, ages and style of tectonism allow us to compare those rocks with the ones from Creporizão Intrusive Suite (1997-1957Ma). Dacite dikes (1992±2Ma) cut across all other rocks, but the temporal relationship among them remains misunderstood, due to the geochemical signature similar to the anorogenic rocks, suggesting it belongs to a distinct and latter magmatic series. Indeed, the dated zircons were probably inherited from host rocks. The mineralized area is restricted to a domain constrained by two major sinistral strike-slip N100°-130E°E faults that comprises the Tocantinzinho granite and sub-volcanic rocks, which were hydrothermally altered, brittle deformed and mineralized during two phases. The first one is characterized by breccias and microfractures infilled with muscovite (1864±5Ma) and pyrite, which contains low gold grades and are restricted to the Tocantinzinho granite. The second phase was controlled by strike-slip and normal tectonics generating tension gashes veins and pull apart breccias infilled with quartz, chlorite, calcite, albite, rutile, pyrite, galena, sphalerite, chalcopyrite, and gold. The gold grade can reach up to 70 ppm in some sulfide-rich veins. These structures are parallel and mainly trends N30-60°E, showing textures and orientated minerals typical of syn-tectonic infilling. Based on petrographical features and argon ages two hypothesis were proposed for the ore genesis: the first one consider a genetic relationship between magmatism and ore fluids for first mineralization stage and the second hypothesis consider a reactivation of pre-existing faults by an extensional tectonism related to the Maloquinha Intrusive Suite magmatism (ca.1880Ma) for this phase. The second mineralization phase is considered as formed as consequence of tectonic reactivation at ca. 1880Ma, in both hypothesis. Both phases in both hypothesis were classified as magmatic-hydrothermal ore mineralization and might be classified as intrusion-related gold systems. However, new field works are important in order to identify and characterize the nature and source of hydrothermal fluids, as well as ore dating and new geochemical and geochronological data of sub-volcanic rocks are imperative to better understand the genesis and evolution of the Tocantinzinho gold deposit. Such results, strongly linked to the fact that the tectonic control seem significant, may help for future exploration and exploitation programs

Electrical arcing in the railway environment radiates wideband noise that can disturb nearbysensitive electronics e.g. signaling systems. High frequency disturbances follow conducting wiresand rails. For Electromagnetic Compatibility reasons, radiation from wire structures is studied atspecific frequencies, to assess the risk to sensitive electrical devices further along the track.The specific problem is to construct a fast and accurate solver for computing the currents inducedby a dipole source on an arbitrary number of parallel wires inside a layered medium. In this project, atwo-layered medium is considered, each medium defined by arbitrary permittivity and permeability.Once the wire currents are known, the fields may be calculated everywhere.The approach is to transform the circular wires into equivalent strips, creating a planarly layeredstructure. The fields from a source in a layered structure may be expanded as a sum of planewaves propagating in the direction of stratification. The strip currents are expanded into Chebyshevpolynomials and together with the fields and boundary conditions, the currents are solved with themode matching technique in the spectral domain.Moreover, a simplified model for strips much narrower than the wavelength is derived, onlyconsidering axial currents, further reducing the complexity of the problem and still exhibiting highaccuracy.Unlike most full wave methods, the spectral domain approach does not rely on spatial discretisationof wires. Since infinitely long wires are considered, they are electrically large and thusconventional full wave methods yield to massive computations as many grid points are required, thusmotivating the spectral domain approach.The result is a linear system of integral equations solving the currents on an arbitrary numberof narrow strips. Results for different configurations of strips and dipole locations are shown andverified by comparing them with a commercial Method of Moments based solver, 4NEC2, using finitelengths of wire.In conclusion, a simple, fast and accurate method has been developed in Matlab for solving thecurrents along parallel strip conductors.
Blixtar längs järnvägen strålar bredbandigt brus som kan störa närligande känslig elektronik t.ex.signaleringssystem. Högfrekventa störningar följer ledningar och spår. För elektromagnetisk förenlighet,studeras strålning från ledningstrukterer vid specifika frekvenser, för att bedömma risken förkänsliga system längre bort längs ledningen.Problemet är att konstruera en snabb och nogrann numerisk lösare för att beräkna strömmarnainducerade av en dipolkälla hos en godtycklig antal parallella ledare innuti en lagrad struktur. Idetta projekt används en tvålagrig struktur, varje medium definierad av godtycklig permittivitet ochpermeabilitet. Då strömmarna i ledningarna är kända, kan fälten bestämmas överallt.Metoden är att transformera de circulära ledarna till ekvivalenta strips, vilket skapar ett plantlagrat struktur. Fält som härör en källa i ett lagrat medium kan expanderas som en summa planavågor som utökar sig i avlagringsrikningen. Strömmar på stripen expanderas som Chebyshev polynomoch tillsammans med fält och gränsvärden, kan strömmarna tas fram med modanpassning ispektrala rummet.Utöver detta, har en simplifierad model för strips mycket smalare än våglängen härleds fram,där enbart strömmar i stripens parallella riktning utses vilket vidare förenklar problemet utan attförlora mycket nogrannhet.Olikt de alra flest helvågsmetoderna, använder sig inte spektrala metoden av rumdiskretiseringav ledare. Eftersom ledarna i frågan är oändligt långa är de elektriskt stora som gör att rumdiskretiseringkommer att orsaka för stora beräkningar då det kräver för många diskretiserings punkter,vilket motiverar valet av spektrala metoden.Resultatet är ett linjärt ekvationssystem bestående av integralekvationer för att lösa strömmarnalängs en godtycklig antal smala ledare. Resultat för olika konfigurationer av strips och dipolpositionär redovisade och överensstämmer väl med den kommersiella Method of Moments baserade lösaren4NEC2 med ändligt långa ledare.Sammanfattningsvis, har det tagits fram en enkel, snabb och nogrann metod i Matlab för attlösa strömmarna längs parallella ledande strips.

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Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
Road Ecology is a scientific discipline that studies the effects of transport’s infrastructure such as roads, railways and canals on the ecosystem. Ecological effects including habitat destruction and fragmentation, increased erosion and pollution, and, particularly disturbing, the roadkill, which can be highly impacting populations of low-density species such as endangered species, having the potential to significantly affect biodiversity. Even with a considerable increase in recent studies on the subject, there are large gaps in knowledge about the effects of highways, and especially on how these effects affect animal populations, man, and ways to minimize or mitigate environmental impacts. These gaps are especially worrying in countries such as Brazil, which opted for a road modal and thus, presents an extensive network of highways. Brazil even develops research and publishes on road ecology, being the third country that contributes most to the world scientific production, but there is a predominance of roadkill studies and a low number of studies on mitigation measures, and roadkill studies are lacking standardization in the methodology adopted by the researchers. In this study, the detection rate of animals of different taxonomic classes was analyzed using different tracking speeds, and it was observed that the speed of 5 km.h-1 is the one that best serves the purpose of pointing to the actual trampling rate. Then within road ecology, several problems affect the human being, but traffic accidents are considered a neglected public health problem, especially in developing countries. There is a need to understand the factors contributing to the aggravation of traffic accidents, and as a contribution to this understanding, this study investigated automobile accidents with runway exit with or without collision in the vegetation of the domain strip. It was found that tree collision increases the probability of mortality (3.16 times) and severity of injury in accidents when vehicles left the roadway.
Ecologia de estradas é uma disciplina científica que estuda os efeitos de infraestruturas de transporte como estradas, ferrovias e canais sobre o ecossistema. Efeitos ecológicos que incluem a destruição e fragmentação do habitat, aumento da erosão e poluição, e, particularmente preocupante, o atropelamento animal(AA), que pode ser altamente impactante para populações de espécies que existem em baixas densidades, como as ameaçadas de extinção, tendo potencial para afetar significativamente a biodiversidade. Mesmo com um aumento considerável de estudos recentes sobre o tema, existem grandes lacunas de conhecimento sobre os efeitos das rodovias, e principalmente sobre como esses efeitos afetam as populações animais e o homem. Essas lacunas são especialmente preocupantes nos países como o Brasil, que optou por um modal rodoviário e assim, apresenta uma extensa rede de rodovias. O Brasil até desenvolve pesquisas e publica sobre ecologia de estradas, sendo o terceiro país que mais contribui com a produção científica mundial, mas há uma predominância de estudos sobre AA e baixo número de estudos sobre medidas mitigadoras, e os estudos sobre AA pecam pela falta de padronização na metodologia adotada pelos pesquisadores. Neste estudo é analisado o índice de detecção de animais de diferentes classes taxonômicas utilizando diferentes velocidades de monitoramento, sendo observado que a velocidade de 5 km.h-1 é a que melhor atende o propósito de apontar a real taxa de atropelamento. Ainda dentro de ecologia de estradas, vários problemas afetam o ser humano, mas os acidentes de trânsito são considerados um problema de saúde pública negligenciado, principalmente em países em desenvolvimento. Há necessidade de compreender os fatores que contribuem para agravamento dos acidentes de trânsito, e como contribuição para essa compreensão, este estudo investigou acidentes automobilísticos com saída de pista com ou sem colisão na vegetação da faixa de domínio. Constatou-se que a colisão com árvore aumenta a probabilidade de mortalidade (3,16 vezes) e gravidade da lesão em acidentes em que os veículos saíram da pista nas rodovias.

This thesis provides the explicit expression of the star-exponential for the action of normal j-groups on their coadjoint orbits, and of the so-called modified star-exponential defined by Gayral et al. Using this modified star-exponential as the kernel of a functional transform between the group and its coadjoint orbits yields an adapted Fourier transform which is also detailed here. The normal j-groups arise in the work of Pytatetskii-Shapiro, who established the one-to-one correspondence with homogeneous bounded domains of the complex space; these groups are also the central element of the deformation formula recently developed by Bieliavsky & Gayral (a non abelian analog of the strict deformation quantization theory of Rieffel). Since these groups are exponential, the results given in this text illustrate the general work of Arnal & Cortet on the star-representations of exponential groups.

As this work is meant to be as self-contained as possible, the first chapter reproduces many definitions introduced by Bieliavsky & Gayral, in order to obtain the expression of the symplectic symmetric space structure on normal j-groups, and of their unitary irreducible representations. The Weyl-type quantizer associated to this symmetric structure is then computed, thus yielding the Weyl quantization map for which the composition of symbols is precisely the deformed product defined by Bieliavsky-Gayral on normal j-groups. A detailed proof of the structure theorem of normal j-groups is also provided.

The second chapter focuses on the expression and properties of the star-exponential itself, and exhibits a useful tool for the computation, namely the resolution of the identity associated to square integrable unitary irreducible representations of the groups. The result thus obtained satisfies the usual integro-differential equation defining the star-exponential. A criterion for the existence of a tempered pair underlying a given tempered structure on Lie groups is proven; the star-exponential functions are also shown to belong to the multiplier algebra of the Schwartz space associated to the tempered structure. Before that, it is shown that all Schwartz spaces that appear in this work are isomorphic as topological vector spaces.

The modified version of this star-exponential is computed in chapter three, first for elementary normal j-groups and then for normal j-groups. It is then used to define an adapted Fourier transform between the group and the dual of its Lie algebra. This transform generalizes (to all normal j-groups) a Fourier transform that was already studied in the “ax+b” case by Gayral et al. (2008), as well as by Ali et al. (2003) in the context of wavelet transforms.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

Network reconstruction is the process of recovering a unique structured representation of some dynamic system using input-output data and some additional knowledge about the structure of the system. Many network reconstruction algorithms have been proposed in recent years, most dealing with the reconstruction of strictly proper networks (i.e., networks that require delays in all dynamics between measured variables). However, no reconstruction technique presently exists capable of recovering both the structure and dynamics of networks where links are proper (delays in dynamics are not required) and not necessarily strictly proper.The ultimate objective of this dissertation is to develop algorithms capable of reconstructing proper networks, and this objective will be addressed in three parts. The first part lays the foundation for the theory of mathematical representations of proper networks, including an exposition on when such networks are well-posed (i.e., physically realizable). The second part studies the notions of abstractions of a network, which are other networks that preserve certain properties of the original network but contain less structural information. As such, abstractions require less a priori information to reconstruct from data than the original network, which allows previously-unsolvable problems to become solvable. The third part addresses our original objective and presents reconstruction algorithms to recover proper networks in both the time domain and in the frequency domain.

Could shareholder primacy, with its assumed short-termist practices, have had its day when it comes to managerial activity centered on creating corporate value? Many business and opinion leaders appear to take this position, not least Jack Welch who famously declared 'shareholder primacy is the dumbest idea in the world!' Indeed, in a post-Crash economy has a wider stakeholder focus with a longer-term outlook superseded any business notions of shareholder primacy and wealth maximization? This research examines these possibilities through a consideration of the narrative companies produce, such as annual reports. From this corpus material, an assessment is made of whether UK managers' perceptions about corporate value generation changed over the period covering the worldwide financial crisis, with respect to their relative favouring of shareholders and stakeholders. The corpus of narrative material used is visualized as a conceptual space in which a conversation reflecting perceptual bias to the generation of corporate value occurs. To explore such corpuses, in order to compare narratives at points either side of the 2008 Crash, a new methodology was devised called narrative staining. Hence, a detection and visual mapping over the period was made possible of managers' changing perceptions concerning primacy (shareholder or stakeholder orientation) with its mediation by termism (a short or long-term bias). Termism is also originally conceived as part of a larger temporal category, which includes a sense of urgency to act (urgent versus non-urgent) that is similarly examined. The investigation reveals that over time perceptual change about value creation happened, though in unanticipated ways. Companies pre-Crash were often short-term stakeholder oriented then moved post-Crash to a long-term shareholder orientation. A focus for this study was the corporate domain, consisting of a selection of FT250 companies. However, managerial perceptions about corporate value creation are influenced not simply by the conversation of the corporate domain but rather by a multi-actor conversation taking place throughout the business environment. To comprehend this effect, the research mines further corpuses that comprise the UK's regulatory domain (hard and soft law), the press (Financial Times and other newspapers), and relevant peripheral stakeholder organizations (including the Confederation of British Industry, the Institute of Directors, and the Trades Union Congress). These organizations demonstrated more complex, unforeseen, perceptual effects as the financial crisis proceeded with many aligning according to their political or business agenda, which also impacted any sense of urgency to act they had. There appears to be no previous attempt at an extensive and multivariate analysis of this nature. And the findings challenge prevalent characterizations of shareholder and stakeholder behaviour. Moreover, the research shows that utilizing a wide set of stakeholder corpuses acts a viable proxy for broader financial perspectives amongst UK organizations. The technique of narrative staining therefore provides insights, hitherto inaccessible, for assessing and consolidating large-scale perceptual bias regarding value creation across the economy. The technique also has significant potential for other applications.

Classical planning is the problem of nding a sequence of actions that take an agent from an initial state to a desired goal situation, assuming deter- ministic outcomes for actions and perfect information. Satis cing planning seeks to quickly nd low-cost solutions with no guarantees of optimality. The most e ective approach for satis cing planning has proved to be heuristic search using non-admissible heuristics. In this thesis, we introduce several such heuristics that are able to take into account costs on actions, and there- fore try to minimize the more general metric of cost, rather than length, of plans, and investigate their properties and performance. In addition, we show how the problem of planning with soft goals can be compiled into a classical planning problem with costs, a setting in which cost-sensitive heuristics such as those presented here are essential.
La plani caci on cl asica es el problema que consiste en hallar una secuencia de acciones que lleven a un agente desde un estado inicial a un objetivo, asum- iendo resultados determin sticos e informaci on completa. La plani caci on \satis cing" busca encontrar una soluci on de bajo coste, sin garant as de op- timalidad. La b usqueda heur stica guiada por heur sticas no admisibles es el enfoque que ha tenido mas exito. Esta tesis presenta varias heur sticas de ese g enero que consideran costes en las acciones, y por lo tanto encuentran soluciones que minimizan el coste, en lugar de la longitud del plan. Adem as, demostramos que el problema de plani caci on con \soft goals", u objetivos opcionales, se puede reducir a un problema de plani caci on clasica con costes en las acciones, escenario en el que heur sticas sensibles a costes, tal como las aqu presentadas, son esenciales.

博士
國立清華大學
數學系
87
In this thesis we study the existence and the symmetry of the solutions of the semilinear elliptic equations -Δu+u=g(u) in infinite strip domains and flask domains. In Chapter 1, we prove the existence of the solutions of the semilinear elliptic equations -Δu+u=g(u) in infinite strip domains by the Decomposition Lemma, and then apply the improved“moving plane”method to prove the symmetry of the solutions. In Chapter 2, consider the semilinear elliptic equations -Δu+au=b|u|^{p-2}u in unbounded domainΩ, we prove the following assertions: (1) αI=αM=αΓ=αΓˊ(2) Let Ω0=Ω1∪Ω2 where Ω1∩Ω2 is bounded, andαi=α(Ωi) the index of J in Ωi for i=0,1,2. We assert that J satisfies the (PS) αi -condition if and only if the inequality α0 0 such that α∞(D_{s}^{r}) admits a minimizer if s> s0, but α∞(D_{s}^{r}) does not admit any minimizer if s< s0, where D_{s}^{r} is an interior flask domain.

by Tam Wai Yip.
Thesis (M.Phil.)--Chinese University of Hong Kong, 1990.
Bibliography: leaves [124]-[127]
ACKNOWLEDGEMENT --- p.i
LIST OF SYMBOLS --- p.ii
Chapter CHAPTER 1 --- INTRODUCTION --- p.1-1
Chapter CHAPTER 2 --- ANALYSIS OF MICROSTRIP ANTENNA ON A PLANAR SURFACE --- p.2-1
Chapter 2.1 --- Dyadic Green's function formulation of a double-patch system --- p.2-3
Chapter 2.1.1 --- Field components --- p.2-4
Chapter 2.1.2 --- Boundary conditions and dyadic Green's function --- p.2-8
Chapter 2.2 --- Microstrip antenna with an airgap --- p.2-14
Chapter 2.3 --- Microstrip antenna with a superstate --- p.2-16
Chapter 2.4 --- Galerkin's method --- p.2-18
Chapter 2.5 --- Numerical computation --- p.2-25
Chapter 2.6 --- Results and discussions --- p.2-30
Chapter CHAPTER 3 --- ANALYSIS OF MICROSTRIP ANTENNA ON SPHERICAL SURFACE --- p.3-1
Chapter 3.1 --- Fields in spherical coordinates --- p.3-3
Chapter 3.1.1 --- solution of scalar Helmholtz equation in spherical coordinates --- p.3-3
Chapter 3.1.2 --- Vector potentials --- p.3-6
Chapter 3.2 --- Cavity model approach --- p.3-10
Chapter 3.2.1 --- Formulation of radiation patterns --- p.3-11
Chapter 3.2.2 --- Results and discussions --- p.3-23
Chapter 3.3 --- Spectral domain approach --- p.3-39
Chapter 3.3.1 --- General formulation --- p.3-39
Chapter 3.3.2 --- Complex resonant frequency --- p.3-48
Chapter 3.3.3 --- Far field radiation pattern --- p.3-51
Chapter 3.3.4 --- Current distribution --- p.3-52
Chapter 3.3.5 --- Limiting case of thin dielectric --- p.3-58
Chapter 3.3.6 --- Results and discussions --- p.3-63
Chapter CHAPTER 4 --- CONCLUSIONS --- p.4-1
REFERENCES
Chapter APPENDIX I --- ASSOCIATED LEGENDRE FUNCTIONS
Chapter APPENDIX II --- SPHERICAL BESSEL FUNCTIONS
Chapter APPENDIX III --- VECTOR LEGENDRE SERIES
Chapter APPENDIX IV --- RESONANT FREQUENCY RELATION FOR THIN DIELECTRIC
Chapter APPENDIX V --- LIST OF PUBLICATIONS THAT ARE PRODUCED BY THE STUDIES

Ni80Fe20 and Ni80Fe20/NiO films and nano-stripes were characterized magnetically through AC and DC susceptibility measurements, and hysteresis loops as a function of field and temperature. While the near-pattern films were characterized in the in-plane configuration only, the nano-stripes were characterized in parallel, transverse and the perpendicular field configurations. The effects of the constrained geometry on the coercivity, exchange bias field, and the superparamagnetic blocking temperature were studied. It was determined that the coercivity, exchange bias field and the superparamagnetic blocking temperature can be controlled, not only by using a patterned media instead of a plane film, but also by the orientation of that pattern.

Leaf rust and stripe rust of wheat (Triticum aestivum L.) are caused by the fungal pathogens Puccinia triticina, and Puccinia striiformis f.sp. tritici, respectively. In North America, the incorporation of adult-plant resistance (APR) genes into breeding lines has been an important strategy to achieve durable resistance to both diseases. Previously, the spring wheat cultivar AC Domain was reported to express an effective level of adult-plant resistance (APR) to leaf rust under field conditions. Early gene postulation work had suggested AC Domain might carry the APR gene Lr34 due to its phenotypic similarity to other Lr34 carrying lines. However, new gene specific markers have shown that AC Domain is not a carrier of Lr34. The objective of this research was to genetically localize the resistance in AC Domain, which is important because the cultivar has frequently been used as a parent in Canadian breeding programs, primarily for its value as a source of pre-harvest sprouting resistance. A mapping population of 185 doubled haploid (DH) lines derived from the cross ‘RL4452’ by ‘AC Domain’ was used for this study. RL4452 is a known carrier of Lr34. During 2011-2012, the DH population was evaluated in field leaf rust nurseries at Saskatoon, SK and Portage, MB and at a stripe rust nursery at Lethbridge, AB. Field results indicated that rust resistance in the mapping population was variable, with lines ranging from highly resistant, to highly susceptible. DH lines carrying Lr34 showed a high level of resistance to both diseases. Thus, the non-Lr34 carriers were genotyped using select SSR markers, and by an Illumina 9k Infinium iSelect SNP assay for subsequent quantitative trait loci (QTL) analysis. QTL analysis revealed that AC Domain donated a major resistance QTL located on chromosome 2BS, that mapped 46 cM proximal to markers linked to Lr16, and explained a significant portion of the leaf and stripe rust phenotypic variance in all test environments. In addition, this QTL was significantly associated with the expression leaf tip necrosis (LTN), reduction in area under the disease progress curve (AUDPC), and coefficient of infection (CI). In certain environments the interaction between the 2B QTL and Lr34 was additive resulting in a superior level of rust resistance. Indoor rust testing showed AC Domain was susceptible to both diseases at the seedling stage. Taken together these results suggest that the identified resistance in AC Domain is likely due to the presence of an APR gene, on chromosome 2BS.

by Terry Kin-chung Lo.
Thesis (M.Phil.)--Chinese University of Hong Kong, 1994.
Includes bibliographical references (leaf 128).
Dedication --- p.i
Acknowledgements --- p.ii
Chapter Chapter 1 --- Introduction
Chapter 1.1 --- Outline of Thesis --- p.1
Chapter 1.2 --- Microstrip to Slotline Transition --- p.3
Chapter 1.3 --- Finite Difference as a Numerical Method --- p.4
Chapter Chapter 2 --- The Method of Finite Difference in Time Domain
Chapter 2.1 --- An Introduction and Brief History --- p.1
Chapter 2.2 --- The Methodology of FDTD --- p.11
Chapter 2.3 --- The Yee's Algorithm --- p.13
Chapter 2.4 --- Stability Criterion --- p.19
Chapter 2.5 --- Interfaces Between Media --- p.21
Chapter 2.6 --- Lattice Truncation Condition --- p.24
Chapter 2.7 --- Error Analysis --- p.28
Chapter 2.8 --- Implementation of Programs --- p.33
Chapter 2.9 --- Summary --- p.35
Chapter Chapter 3 --- Absorbing Boundary Conditions
Chapter 3.1 --- Introduction --- p.39
Chapter 3.2 --- Mur's ABC --- p.40
Chapter 3.3 --- Liao's ABC --- p.42
Chapter 3.4 --- Dispersive ABC --- p.45
Chapter 3.5 --- Comparison between Mur's ABC & Liao's ABC --- p.47
Chapter 3.6 --- "Comparison among Mur's 1st Order ABC, Liao's ABC & DBC" --- p.51
Chapter 3.7 --- Summary --- p.55
Chapter Chapter 4 --- Microstrip-Slotline Transitions
Chapter 4.1 --- Introduction --- p.57
Chapter 4.2 --- Approach --- p.59
Chapter 4.3 --- Single Quarter-Wave Microstrip-Slotline Transitions --- p.67
Chapter 4.4 --- Single Y-Strip-Slotline Transitions --- p.78
Chapter 4.5 --- Shorted-Stub Y-Strip-Slotline Transitions --- p.88
Chapter 4.6 --- Y-Strip-180°-Slotline Transitions --- p.96
Chapter 4.7 --- Y-Strip-Y-Slot Transitions --- p.104
Chapter 4.8 --- Y-Strip-Open-Stub-Y-Slot Transitions --- p.112
Chapter 4.9 --- YY-Transitions --- p.120
Chapter 4.10 --- Summary --- p.127
Chapter Chapter 5 --- Conclusions & Future Development
Chapter 5.1 --- Conclusions --- p.129
Chapter 5.2 --- Future Development --- p.131
Appendix
Fortran 77 Code of Single Quarter-Wave Microstrip-Slotline Transition --- p.132

In recent years there has been a rapid growth in the fast passenger ferry industry. Initially speed was the main selling point for designers, builders and operators, but as competition and choice have increased passengers are demanding better seakeeping performance. In addition designers and builders are starting to see the benefits of better seakeeping not only in terms of passenger comfort but in terms of structural strength and loading, allowing reduced structural weight and its many associated advantages. Two aspects of the seakeeping of fast ships are addressed in this thesis: response computation and the behaviour of semi-SWATH designs. Motion and load prediction for the practising naval architect has traditionally been done using strip theories, usually one closely related to the well known theory of Salvesen, Tuck and Faltinsen. This is a low Froude number theory, and although it is still being used, often successfully, for fast ships there is no rational justification for its validity in these cases. As speeds are increasing it is becoming imperative that an equivalent analysis tool suitable for higher Froude numbers be developed. This thesis proposes such a theory, based on calculation of two dimensional hydrodynamic potentials in a fixed reference frame in place of the traditional moving one. This strip theory of necessity is a time domain theory, which also allows the possi- bility of introducing non-linearities, random sea input, and even slamming events (although only the first of these is discussed in any detail in the thesis). Validation has involved comparison with traditional theory and tank testing. Most notably pitch and coupling effects have shown improved predictions, but heave tends to be over predicted. The main candidates for explana- tion of this phenomenon are argued to be wake shedding, hull entry effects, steady-unsteady interactions and three-dimensionality. The majority of fast ferries being built at present have very conventional hull forms below the calm waterline. These have poorer seakeeping than their slower equivalents because their natural frequencies are encountered in longer waves, and traditionally designers have relied on lifting surfaces to counteract the increased motions. As these vessels get faster this approach will become less viable in terms of forces involved and appendage drag penalty. The type of hull form that will reduce motion accelerations without too much sacrifice of drag is not obvious, and a family of semi-SWATHs has been investigated as a possible alternative hull form. The investigation shows that as speed is increased the advantages of SWATH like forms become much greater if the criterion is to reduce accelerations.

Simulating wave propagation in microstrip lines with Gyrotropic magnetic substrate is considered in this thesis. Since the static internal field distribution has an important effect on the device behavior, accurate determination of the internal fields are considered as well. To avoid the losses at microwave frequencies it is assumed that the magnetic substrate is saturated in the direction of local internal field. An iterative method to obtain the magnetization distribution has been developed. It is applied to a variety of nonlinear nonuniform magnetic material configurations that one may encounter in the design stage, subject to a nonuniform applied field. One of the main characteristics of the proposed iterative method to obtain the static internal field is that the results are supported by a uniqueness theorem in magnetostatics. The series of solutions Mn,Hn, where n is the iteration number, minimize the free Gibbs energy G(M) in sequence. They also satisfy the constitutive equation M = χH at the end of each iteration better than the previous one. Therefore based on the given uniqueness theorem, the unique stable equilibrium state M is determined. To simulate wave propagation in the Gyrotropic magnetic media a new FDTD formulation is proposed. The proposed formulation considers the static part of the electromagnetic field, obtained by using the iterative approach, as parameters and updates the dynamic parts in time. It solves the Landau-Lifshitz-Gilbert equation in consistency with Maxwell’s equations in time domain. The stability of the initial static field distribution ensures that the superposition of the time varying parts due to the propagating wave will not destabilize the code. Resonances in a cavity filled with YIG are obtained. Wave propagation through a microstrip line with YIG substrate is simulated. Magnetization oscillations around local internal field are visualized. It is proved that the excitation of magnetization precession which is accompanied by the excitation of magnetostatic waves is responsible for the gap in the scattering parameter S12. Key characteristics of the wide microstrip lines are verified in a full wave FDTD simulation. These characteristics are utilized in a variety of nonreciprocal devices like edgemode isolators and phase shifters.

The goal of this dissertation is to examine, in the anisotropic least gradient problem, what is the influence of the geometry of the domain and properties of the anisotropy on existence,uniqueness and regularity of the solutions. In this dissertation we consider three di erent situations. The first one is the case when φ, the function which defines the anisotropy, is a norm. Then, we show existence of solutions to the anisotropic least gradient problem for strictly convex domains and boundary data which are continuous almost everywhere. We are particularly interested in the case when φ is not strictly convex; then, the lack of dependence on location of φ is particularly important. In the second case, φ may depend also on location, but we assume high regularity and uniform convexity of φ. Then, apart from a result analogous to the previous one, we may also use e.g. the maximum principle for minimal surfaces to show that while for fixed boundarydata are not necessarily unique, all the solutions have the same frame of superlevel sets. Finally, in the third case we focus on domains Ω which are not bounded convex sets. We consider two situations: when Ω is a strictly convex set, but it is unbounded, and when the boundary of Ω is not connected. For clarity of the presentation in the second case we restrict most of the discussion to the case, when Ω is an annulus on the plane, which enables us to use methods typical for the optimal transport problem.
Celem niniejszej pracy jest zbadanie, jaki wpływ na istnienie, jednoznaczność i regularność rozwiązań w anizotropowym zagadnieniu najmniejszego gradientu mają geometria obszaru oraz właściwości zadanej anizotropii. W pracy poruszane są trzy różne sytuacje. W pierwszej z nich funkcja φ zadająca anizotropię jest normą. Wówczas pokazujemy istnienie rozwiązań anizotropowego zagadnienia najmniejszego gradientu dla ściśle wypukłych obszarów oraz danych brzegowych ciągłych prawie wszędzie. Szczególnie interesuje nas przypadek, gdy φ nie jest ściśle wypukła; wtedy brak zależności φ od położenia gra szczególną rolę. Drugi przypadek dotyczy sytuacji, gdy φ może zależeć także od położenia, jednak zakładamy wysoką regularność oraz jednostajną wypukłość φ. Wówczas oprócz wyniku analogicznego do poprzedniego możemy także użyć m.in. zasady maksimum dla powierzchni minimalnych do pokazania, że dla ustalonych danych brzegowych rozwiązania niekoniecznie są jednoznaczne, ale wszystkie rozwiązania mają identyczną strukturę poziomic. Wreszcie trzeci przypadek dotyczy sytuacji, gdy dziedzina Ω nie jest obszarem ograniczonym oraz wypukłym. Rozważamy dwie sytuacje: kiedy Ω jest zbiorem ściśle wypukłym, ale nieograniczonym, oraz kiedy Ω ma niespójny brzeg. Dla czytelności wywodu w drugim przypadku ograniczamy większość dyskusji do przypadku, kiedy Ω jest pierścieniem na płaszczyźnie, co umożliwia stosowanie metod pochodzących z zagadnienia optymalnego transportu.