Dissertations / Theses on the topic 'Moment map'

To see the other types of publications on this topic, follow the link: Moment map.

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 35 dissertations / theses for your research on the topic 'Moment map.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.

1

Otto, Michael. "Symplectic convexity theorems and applications to the structure theory of semisimple Lie groups." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1084986339.

Full text
Abstract:
Thesis (Ph. D.)--Ohio State University, 2004.
Title from first page of PDF file. Document formatted into pages; contains v, 88 p. Includes bibliographical references (p. 87-88). Available online via OhioLINK's ETD Center
APA, Harvard, Vancouver, ISO, and other styles
2

Fedosov, Boris. "Non-Abelian reduction in deformation quantization." Universität Potsdam, 1997. http://opus.kobv.de/ubp/volltexte/2008/2510/.

Full text
Abstract:
We consider a G-invariant star-product algebra A on a symplectic manifold (M,ω) obtained by a canonical construction of deformation quantization. Under assumptions of the classical Marsden-Weinstein theorem we define a reduction of the algebra A with respect to the G-action. The reduced algebra turns out to be isomorphic to a canonical star-product algebra on the reduced phase space B. In other words, we show that the reduction commutes with the canonical G-invariant deformation quantization. A similar statement in the framework of geometric quantization is known as the Guillemin-Sternberg conjecture (by now completely proved).
APA, Harvard, Vancouver, ISO, and other styles
3

Jelének, Marek. "Nepřímé měření momentu na výstupu převodovky zatěžovacího pohonu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-376913.

Full text
Abstract:
For loading of excavator drive units, it is necessary to use electromechanical loads with a high torque up to 16,000 Nm in a low speed range from 0 to 150 min-1 with a maximum output of 50 kW. The electromechanical load consists of an asynchronous dynamometer assembly with a tilting torque measurement system in conjunction with a front three-speed gearbox. The dynamometer is powered by a converter with vector control. To determine the torque at the gearbox output, a correction must be made and the influence of operating temperature and operating speed must be taken into account. Experimental measurement of these influences and dependencies makes it possible to create a mathematical model that can be implemented in the power converter for torque control at the output of the gearbox. The aim of the master thesis is a brief design of the loading drive, design an implementation of experimental measurement of efficiency maps and evaluation of the influence of inefficiency of gearbox efficiency.
APA, Harvard, Vancouver, ISO, and other styles
4

Roeser, Markus Karl. "The ASD equations in split signature and hypersymplectic geometry." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:7d46ffc8-6d12-4fec-9450-13d2c726885c.

Full text
Abstract:
This thesis is mainly concerned with the study of hypersymplectic structures in gauge theory. These structures arise via applications of the hypersymplectic quotient construction to the action of the gauge group on certain spaces of connections and Higgs fields. Motivated by Kobayashi-Hitchin correspondences in the case of hyperkähler moduli spaces, we first study the relationship between hypersymplectic, complex and paracomplex quotients in the spirit of Kirwan's work relating Kähler quotients to GIT quotients. We then study dimensional reductions of the ASD equations on $mathbb R^{2,2}$. We discuss a version of twistor theory for hypersymplectic manifolds, which we use to put the ASD equations into Lax form. Next, we study Schmid's equations from the viewpoint of hypersymplectic quotients and examine the local product structure of the moduli space. Then we turn towards the integrability aspects of this system. We deduce various properties of the spectral curve associated to a solution and provide explicit solutions with cyclic symmetry. Hitchin's harmonic map equations are the split signature analogue of the self-duality equations on a Riemann surface, in which case it is known that there is a smooth hyperkähler moduli space. In the case at hand, we cannot expect to obtain a globally well-behaved moduli space. However, we are able to construct a smooth open set of solutions with small Higgs field, on which we then analyse the hypersymplectic geometry. In particular, we exhibit the local product structures and the family of complex structures. This is done by interpreting the equations as describing certain geodesics on the moduli space of unitary connections. Using this picture we relate the degeneracy locus to geodesics with conjugate endpoints. Finally, we present a split signature version of the ADHM construction for so-called split signature instantons on $S^2 imes S^2$, which can be given an interpretation as a hypersymplectic quotient.
APA, Harvard, Vancouver, ISO, and other styles
5

ITAKURA, Fumitada, Kazuya TAKEDA, and Tran Huy DAT. "Gamma Modeling of Speech Power and Its On-Line Estimation for Statistical Speech Enhancement." Institute of Electronics, Information and Communication Engineers, 2006. http://hdl.handle.net/2237/15052.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Zergane, Amel. "Séparation des représentations des groupes de Lie par des ensembles moments." Thesis, Dijon, 2011. http://www.theses.fr/2011DIJOS086/document.

Full text
Abstract:
Si (π, H) est une représentation unitaire irréductible d'un groupe de Lie G, on sait lui associer son application moment Ψπ. La fermeture de l'image de Ψπ s'appelle l'ensemble moment de π. Généralement, cet ensemble est Conv(Oπ), si Oπ est l'orbite coadjointe associée à π. Mais il ne caractérise pas π : deux orbites distinctes peuvent avoir la même enveloppe convexe fermée. On peut contourner cette non séparation en considérant un surgroupe G+ de G et une application non linéaire ø de g* dans (g+)* telle que, pour les orbites générique, ø(O) est une orbite et Conv (ø(O)) caractérise O. Dans cette thèse, on montre que l'on peut choisir le couple (G+, ø), avec ø de degré ≤ 2 pour tous les groupes nilpotents de dimension ≤ 6, à une exception près, tous les groupes résolubles de dimension ≤ 4, et pour un exemple de groupe de déplacements. Ensuite, on étudie le cas des groupes G = SL(n, R). Pour ces groupes, il existe un tel couple avec ø de degré n, mais il n'en existe pas avec ø de degré 2 si n>2, il n'en existe pas avec ø de degré 3 si n=4. Enfin, on montre que l'application moment Ψπ est celle d'une action fortement hamiltonienne de G sur la variété de Fréchet symplectique PH∞. On construit un foncteur qui associe à tout G un surgroupe de Lie Fréchet G̃, de dimension infinie et, à tout π de G, une action π̃ fortement hamiltonienne, dont l'ensemble moment caractérise π
To a unitary irreducible representation (π,H) of a Lie group G, is associated a moment map Ψπ. The closure of the range of Ψπ is the moment set of π. Generally, this set is Conv(Oπ), if Oπ is the corresponding coadjoint orbit. Unfortunately, it does not characterize π : 2 distincts orbits can have the same closed convex hull. We can overpass this di culty, by considering an overgroup G+ for G and a non linear map ø from g* into (g+)* such that, for generic orbits, ø(O) is an orbit and Conv( ø(O)) characterizes O. In the present thesis, we show that we can choose the pair (G+,ø), with deg ø ≤2 for all the nilpotent groups with dimension ≤6, except one, for all solvable groups with diemnsion ≤4, and for an example of motion group. Then we study the G=SL(n,R) case. For these groups, there exists ø with deg ø =n, if n>2, there is no such ø with deg ø=2, if n=4, there is no such ø with deg ø=3. Finally, we show that the moment map Ψπ is coming from a stronly Hamiltonian G-action on the Frécht symplectic manifold PH∞. We build a functor, which associates to each G an infi nite diemnsional Fréchet-Lie overgroup G̃,and, to each π a strongly Hamiltonian action, whose moment set characterizes π
APA, Harvard, Vancouver, ISO, and other styles
7

Gonçalves, Guilherme Casas. "Rudimentos de mecânica, ações hamiltoneanas e aplicação momento." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-15072015-105721/.

Full text
Abstract:
Essa dissertação trata de geometria simplética e suas aplicações, apresentando conceitos tais como o gradiente simplético e também o teorema de Darboux. Discutimos a formulação Lagrangeana da mecânica, apresentando as equações de Euler-Lagrange e, usando a geometria simplética, mostramos como estes naturalmente evoluem para o formalismo Hamiltoneano e as equações de Hamilton. Introduzimos também o conceito da métrica de Jacobi e demonstramos o teorema de Noether. Apresentamos o conceito de ações simpléticas e Hamiltoneanas, bem como aplicações momento e comomento. São demonstrados resultados importantes como o teorema de Kirillov-Kostant-Sourieau para órbitas coadjuntas e a redução simplética de Marsden-Weinstein-Meyer. Os resultados centrais apresentados são o teorema de Atiyah-Guillemin-Steinberg de convexidade, o teorema de Schur e Horn para matrizes unitárias e o teorema de Delzant, este último sendo apresentado apenas com uma ideia da prova.
This thesis is about symplectic geometry and its applications, presenting concepts such as the symplectic gradient and also Darboux\'s theorem. We discuss the Lagrangian formulation of mechanics, presenting the Euler-Lagrange equations and, using symplectic geometry, show how those naturally evolve into the Hamiltonian formalism and the Hamilton equations. We instroduce also the concept of the Jacobi metrics and prove Noether\'s theorem. We also introduce the concept of symplectic and Hamiltonian actions as well as moment and comoment maps. We prove important results such as the Kirillov-Kostant-Sourieau theorem for coadjoint orbits and the symplectic reduction of Marsden-Weinstein-Meyer. The central results presented are the convexity theorem of Guillemin-Atiyah-Steinberg, the Schur and Horn theorem for unitary matrices and the Delzant theorem, this last one being presented only with an idea of the proof.
APA, Harvard, Vancouver, ISO, and other styles
8

Kjelleryd, Oskar. "Illustrerade klättringsmoment : En studie kring hur man påminner om praktiska moment." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-19319.

Full text
Abstract:
I detta arbete har jag undersökt hur man kan tillämpa teorier inom informationsdesign för att gestalta en designlösning som hjälper klättrare att minnas moment från topprepskursen.Svenska klätterförbundet vill utforma ett material med information om klättringsmoment som genomförts under topprepskursen. Materialet ska ges ut till examinerad klättrare i samband med att topprepskursen inomhus avklarats, för att påminna om vad för moment som genomförts under kursen. Tidigare material som ska fylla samma syfte finns tillgängligt men är inte utvecklat för att ges ut i samband med avklarad kurs. En designlösning som utifrån teorier inom informativ bild och kognition har producerats och testats genom öppna observationer. Resultatet i arbetet var att sju av åtta testpersoner i en observation kunde minnas hur ett praktiskt moment skulle utföras utifrån designförslaget.
APA, Harvard, Vancouver, ISO, and other styles
9

OLIVEIRA, Allyson dos Santos. "O Teorama da Convexidade do Mapa do Momento." Universidade Federal de Pernambuco, 2007. https://repositorio.ufpe.br/handle/123456789/7567.

Full text
Abstract:
Made available in DSpace on 2014-06-12T18:33:36Z (GMT). No. of bitstreams: 2 arquivo8717_1.pdf: 683788 bytes, checksum: f2a68fef055bf7afc06e875675d9e54f (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2007
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Nesta dissertação apresentamos o teorema da convexidade de Atiyah-Guillemin-Sternberg sobre a imagem do mapa do momento de uma ação Hamiltoniana de um toro sobre uma variedade simplética compacta e conexa. Este resultado fornece, em certo sentido, uma generalização para o teorema de Schur sobre a relação entre os autovalores e os elementos da diagonal das matrizes Hermitianas. Com essa finalidade, discutimos a estrutura simplética sobre variedades, o conceito de Grupos de Lie e as ações destes grupos sobre tais variedades
APA, Harvard, Vancouver, ISO, and other styles
10

Pierce, Sarah. "'It's time man. It feels imminent' : politics at the moment of exposition." Thesis, Goldsmiths College (University of London), 2015. http://research.gold.ac.uk/11213/.

Full text
Abstract:
This PhD is written in the context of the Curatorial/Knowledge programme at Goldsmiths College. It deals foremost with a conversation between art practice and the curatorial, where a thesis emerges as a consideration of art practice as more than just the work of an artist. In the context of the dissertation, art practice “stages” tensions between official, institutional and situated knowledge and knowledges that are unpredictable, unfixed, and uncontained — tensions that are at the heart of what is meant by “curatorial/knowledge. ” I make a distinction between the exhibition as a bracketed, temporally bound event, and “the moment of exposition” as a fleeting, intimacy that occurs unexpectedly and unintentionally as our exposure to the Other. The moment of exposition involves an exposure that is not necessarily formalised or even actualised in the exhibition, but like the exhibition involves some degree of publicness. A main question of the dissertation asks how regimes of legibility, efficacy, and legitimacy limit inhabitations of the political; and conversely, how remaining at the margins of institution is a way of “being” political. Part of this investigation involves differences between practices, not to be glossed over — differences that are key to the curatorial as a political mode of “being. ” The submission is made up of three main elements that form a textual/theoretical, material/archival work. These are: (1) A dimension of critical writing or dissertation that has two large sections: (a) The Learning Community (b) The Community of the Exhibition (2) Four appendices related to projects that took place in parallel to the writing. (3) An archive, which presents a major component of research in the form of a book project carried out wholly in the context of my doctoral research. Sketches of Universal History Compiled from Many Authors by Sarah Pierce (London: Book Works, 2013) demonstrates a primary analytic situation for the problematics of my research.
APA, Harvard, Vancouver, ISO, and other styles
11

Kopečný, Josef. "Návrh nové metody pro stereovidění." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2008. http://www.nusl.cz/ntk/nusl-235903.

Full text
Abstract:
This thesis covers with the problems of photogrammetry. It describes the instruments, theoretical background and procedures of acquiring, preprocessing, segmentation of input images and of the depth map calculating. The main content of this thesis is the description of the new method of stereovision. Its algorithm, implementation and evaluation of experiments. The covered method belongs to correlation based methods. The main emphasis lies in the segmentation, which supports the depth map calculation.
APA, Harvard, Vancouver, ISO, and other styles
12

Larsson, Jessica, and Sara Olén. "“Det är bara ett moment som man, du vet, susar förbi” : - en kvalitativ intervjustudie om vardagligt lärande i hallen." Thesis, Uppsala universitet, Institutionen för pedagogik, didaktik och utbildningsstudier, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-428782.

Full text
Abstract:
Syftet med denna studie är att titta närmare på hur pedagoger som är verksamma inom förskolan ser på vardagligt lärande i hallen. De frågeställningar som besvaras i studien är;  hur används hallen som en del i det vardagliga lärandet? Vilka möjligheter och svårigheter upplever pedagogerna att det finns i hallen och hur/när kommer dessa till uttryck? Samt finns det några skillnader mellan hur de som arbetar med yngre respektive äldre barn ser på det vardagliga lärandet i hallen? För att besvara dessa frågor använde vi oss av kvalitativa intervjuer som genomfördes med tio pedagoger på fyra olika förskolor. Av dessa tio arbetade fem av dem med yngre barn 1–3 år medan de andra fem arbetade med äldre barn 3–5 år. Studiens resultat och analys är uppdelad i två där del 1 berör pedagoger som arbetar med de yngre barnen och del 2 berör pedagoger som arbetar med de äldre barnen. Materialet vi fick in har analyserats och diskuterats utifrån ett sociokulturellt perspektiv och de centrala begrepp som används i vår studie är kontext, mediering, kommunikation och scaffolding. Resultatet visar att det i hallen både finns möjligheter och svårigheter. Pedagogerna beskriver till exempel att möjligheten att utveckla barnens självständighet är stor i hallen och att många barn i hallen samtidigt är en av svårigheterna som framkom i resultatet. Vidare går det att utläsa skillnader mellan hur pedagoger arbetar med de olika åldersgrupperna. Bland de yngre barnen används det till exempel mer språk och hjälp medan pedagogerna berättar att de äldre barnen bör testa mer själva innan de får hjälp. Resultatet visar att synen på vardagligt lärande är likvärdig. Pedagogerna beskriver att vardagligt lärande är de lärandesituationer som inte är planerade undervisningstillfällen utan det lärandet som uppkommer spontant i vardagliga rutinsituationer. Det vardagliga lärandet i hallens kontext beskrivs bland annat genom att barnen får öva på att sätta ord på sina kläder, räkna fingrar på vantar och tilliten till sin egen förmåga då barnen övar på att klä på sig själva.
APA, Harvard, Vancouver, ISO, and other styles
13

Chauca, Genaro Pablo Zamudio. "Variedades de Poisson e suas aplicações na descrição semiclássica de spin." Universidade Federal de Juiz de Fora (UFJF), 2012. https://repositorio.ufjf.br/jspui/handle/ufjf/4714.

Full text
Abstract:
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-29T14:01:29Z No. of bitstreams: 1 genaropablozamudiochauca.pdf: 295489 bytes, checksum: 18212d3cbd798de7a3d5a0a546393c3c (MD5)
Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-29T19:44:50Z (GMT) No. of bitstreams: 1 genaropablozamudiochauca.pdf: 295489 bytes, checksum: 18212d3cbd798de7a3d5a0a546393c3c (MD5)
Made available in DSpace on 2017-05-29T19:44:50Z (GMT). No. of bitstreams: 1 genaropablozamudiochauca.pdf: 295489 bytes, checksum: 18212d3cbd798de7a3d5a0a546393c3c (MD5) Previous issue date: 2012-03-29
CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
Em este trabalho estudamos algumas estruturas matemáticas presentes no modelo semiclássico para o spin não relativístico proposto nas referências [5] e [6]. Obtemos as equações semiclássicas de movimento para o spin não relativístico aplicando o teorema de Ehrenfest à equação de Pauli. Olhando o spin S como um momento angular interno, identicamos ele como a aplicação de momento ligada à ação de Poisson de SO(3) sobre o espaço de fase interno R6. Para eliminar os graus de liberdade extras presentes no modelo restringimos a dinâmica a uma superfície de spin V3 impondo vínculos. Além disso, mostramos que a superfície de spin V3 tem estrutura de fibrado com base S2, fibra típica SO(2) e com aplicação de projeção S. Finalmente apresentamos a formulação do problema variacional para o modelo.
In this work we study some mathematical structures arising in a nonrelativistic spinningparticle model proposed in [5] and [6]. We obtain the semiclassical equations of motion from the Pauli equation via the Ehrenfest theorem. Looking for the spin S as an intrisic angular momentum, we identify it with the momentum map of the SO(3) Poisson action on the inner phase space R6. In order to eliminate the extra degrees of freedom, we impose some constraints which restrict the evolution of the system on the spin surface V3. We show that V3 is a fiber bundle with base S2, standard fiber SO(2) and projection S. Finally, we present the formulation of variational problem for the model.
APA, Harvard, Vancouver, ISO, and other styles
14

Lavin, Matthew Josef. "Collaborative momentum: the author and the middle man in U.S. literature and culture." Diss., University of Iowa, 2012. https://ir.uiowa.edu/etd/1352.

Full text
Abstract:
In the frame introduction to Willa Cather's My Ántonia (1918), an unnamed author encounters her childhood friend Jim Burden on a cross-country train. Jim asks the author why she has never written anything about their mutual friend Ántonia. To answer Jim's criticism, she proposes they both write stories about Ántonia, but only Jim honors the agreement. The rest of the novel is put forth as Jim's manuscript "substantially" as he brought it to the author (xii). This scenario is but one of several ways My Ántonia evokes Cather's experience ghostwriting S.S. McClure's My Autobiography (1914) for, just as the authorial voice in My Ántonia dissolves into Jim's, Cather had to adopt McClure's perspective to write her former employer's life story. Going further, Cather worked closely with her book editor Ferris Greenslet and the production editor R.L. Scaife to be sure Houghton Mifflin would paginate the introduction with roman numerals and thereby produce the effect of a true authorial preface. The introduction recalls the preface of McClure's autobiography, which acknowledged Cather for "cooperation" that contributed to "the very existence" of his book. Interpreting My Ántonia and My Autobiography as projects connected by authorial process, textual allusion, and even typesetting suggests the complicated and elusive nature of collaborative labor in the literary marketplace, as well as the extent to which modern literary texts responded to those complexities. Working on a task or project with a partner or in a group can frustrate, energize or empower those involved, but whatever feelings it inspires, interactive labor often has a life of its own. This is the idea of collaborative momentum. My dissertation examines relationships among authors, agents, editors, publishers, and unofficial "middle men" to argue that supportive and adversarial cycles of interactive labor in the modern American literary marketplace created the basic parameters of modern authorship. I show that as professional specialization becomes more rigid and institutionalized, the literary field paradoxically created new spaces for nebulous but crucial cooperative labor. In particular, the effect I call collaborative momentum facilitated the exchange of economic and symbolic capital. Additionally, I show that narratives of the modern period are inextricably invested in corporate and institutional labor systems that surround them and can be interpreted as rhetorical attempts to reform and improve those systems. By analyzing the author's cultural identity in relation to rising institutional collaborators of the modern era, I contribute to the steadily growing field of authorship studies while adding to ongoing scholarly conversations about individual authors and texts. My chapters analyze the systemic production of literary identity, reciprocal relationships between editors and authors, the modern apparatus of literary debut, and the role bibliophilia and book collecting played in the production of The New Negro. I therefore highlight four paradigmatic examples of interactive labor while simultaneously emphasizing that collaborative momentum as I describe it was crucial not only to those with privilege but also to individuals and groups struggling against inequality, whether it was Salish novelist D'Arcy McNickle, Alain LeRoy Locke, or self-employed literary agent Flora May Holly. My work helps scholars see a power structure that granted disproportionate credibility to white men as literary creators and publishing industry insiders, yet it also shows a modern American literary culture shaped as much by the experience of marginalized individuals and groups negotiating a discriminatory publishing industry as it was by aesthetic contests between popular fiction and high modernism. My first chapter, Character, Personality, and the Editor Figure: William Dean Howells and the Institution of Image-Building establishes that the same cultural logic that allowed Samuel Clemens to develop a public persona as a fictional character also empowered William Dean Howells to create his literary identity as the nation's foremost editor figure. Further, I argue that image-building was a collaborative affair; Howells and many others helped define Mark Twain, and countless authors and critics came to define Howells as the Dean of American Letters in the 1890s and as America's "pious old maid" after his death in 1920. I argue that Howells' persona-work extends to his novel A Hazard of New Fortunes (1890). The main characters--co-founders of a fictional literary magazine--have contrasting identities: one is ostentatious but lacks substance; the other is so unsure he hardly has an identity. Labor crises at the magazine and in the city streets gesture at the problematic nature of a personality-driven culture that had come to define selfhood without emphasizing a moral or ethical element. In chapter two, "Reciprocity and the `Real' Author: Willa Cather as S.S. McClure's Ghostwriter," I trace a cycle of debt--monetary and symbolic--from McClure's rise as magazine editor to a moment of financial crisis in 1912 that led his corporate board to oust him from his own magazine. To pay off his debts, he asked Willa Cather to author his autobiography. I read the ghostwriting project as an example of how mutual debt is generative, for Cather accepted the role out of personal loyalty and took no money for her work. Cather's fictional works, including My Ántonia and The Professor's House (1925), engage with the cycle of debt and indebtedness and imagine a narrative exchange unclouded by any question of money but tied, instead, to a dream of self-sacrificing friendship. My article "It's Mr. Reynolds Who Wishes It: Profit and Prestige Shared by Cather and Her Literary Agent," in Cather Studies Volume 9, "Willa Cather and Modern Cultures," draws on material from this chapter. My third chapter, "Discovery of the Month: D'Arcy McNickle and the Apparatus of Literary Debut" takes up as its interpretive focus changing institutions of literary career-launching. My approach brings together two scholarly conversations, one preoccupied with McNickle's refinement of his perception of Native cultures and the other, informed by a history of the book methodology, concerned with the cultural systems that codified twentieth-century authorial identity and credibility. McNickle is an important example of how institutions of discovery functioned. The exceptional aspects of McNickle's story--the nine-year duration of his effort to publish his first book, his outsider identity, and the number of avenues he tried in order to become established make him an ideal example. To better understand McNickle's relationship with literary agent Ruth Rae, I frame my analysis with the story of the literary agent's rise as an integral figure in literary debut. Turning to McNickle's fiction in the second part of this chapter, I analyze his The Surrounded as a reaction to cultural institutions of literary discovery. McNickle narrates the tragedy of failed mediation and gestures at an alternative model of interaction. He embeds this thematic exploration in his allusions to the Salish oral tradition, so that the text itself mediates an experience of cultural discovery. Chapter four, "Irrepressible Anthologies, Collectible: Bibliophilia and Book Collecting in the New Negro," continues my analysis of the literary middle man's collision with American modernity by tracing the intersection of anthology, book collecting, and bibliophilia as they pertain to The New Negro's book design, artistic form, and multi-generic content. While recent studies have linked the anthology to Boazian ethnography and modernist collage, I provide a more immediate reading of the philosophies of collecting inherent to modern and African American print cultures. I read The New Negro as a book production process structured by efforts to produce an object worthy of being collected. My also analyzes of how the anthology's book design interacts with the positions on materiality and collecting at play in its collected prose and poetry. This case study of the creator-intermediary as collector historicizes modern book collecting and appreciates African American bibliophiles as an alternative to the dominant white American and European book collecting traditions. Appreciating these distinctions suggests, ultimately, that a significant aspect of the exchange of economic and symbolic capital in the modern age was to mediate a contested present day by refashioning ideas about the past.
APA, Harvard, Vancouver, ISO, and other styles
15

Menzio, Davide. "Long term chaotic attitude behaviour on highly eccentric orbits : INTEGRAL Case Study." Thesis, KTH, Farkost och flyg, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-203809.

Full text
Abstract:
The main issues discussed in this paper are related to the refinement of the on-ground casualty risk computation for the specific case of INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL). The current approach, unable to predict the spacecraft attitude motion, assumes random tumbling motion as initial condition to simulate the fragmentation process. The wide experience in break-up analysis, acquired after years of practice with simulation, identified attitude to be one of the major drivers of uncertainty. The Space Debris Office (SDO) demanded a specific research in the field of the long-term propagation applied to the attitude motion and INTEGRAL offered the perfect test bench to conduct a preliminary study in this direction. In particular, observing whether environmental torques were able to trigger stable attitude motion, maintainable till re-entry, was considered to be the major challenge. The propagation of coupled orbital􀀀attitude motion for a random attitude configuration represents only one side of the coin. Indeed, chaos theory analysis constituted the other. The use of the Poincaré map in a non-canonical way managed to bring evidence for constrained motion in the angular rate motion of INTEGRAL, under gravity perturbations. Such results allowed to conduct further investigation on the overall attitude motion and estimate that the attitude configuration at the re-entry appears as precession about the maximum axis of inertia, in the majority of the cases.
De aspekter som behandlas i detta examensarbete är relaterade till skaderisken när rymdskrot som passerar atmosfären och landar på marken. Detta illustreras för en specifik satellit: INTEGRAL. Den nuvarande strategin som används i rymdindustrin är oförmögen att tillräckligt noggrant prediktera satellitens at-titydförändring vid atmosfärsinträdet och antar därför en stokastisk tumlande rörelse som initialvillkor för en analys av sönderdelningen av farkosten när den passerar atmosfären. Den erfarenhet som finns i rymdindustrin kring sönderdelningssimuleringar har identifierat att attityden är den faktor som genererar störst osäkerhet i resultaten. För att bättre förstå attitydens betydelse användes INTEGRAL i den fallstudie som presenteras i denna rapport. Specifikt studerades hur externa kraftmoment från rymdmiljön kan skapa en stabil attitydrörelse, som behålls ända till farkostens inträde i atmosfären. Propageringen av den kopplade rörelsen bana-attityd för en stokastisk attitydkonfiguration representerar endast en del av denna analys, där kaosteori representerar den andra delen. Med hjälp av Poincaré-mappning har simuleringar som indikerar en begränsad vinkelhastighet för INTEGRAL-satelliten när den utsätts för gravitationsstörning. I majoriteten av de analyserade fallen representerades attityden av en precession kring den största huvudtröghetsaxeln.
APA, Harvard, Vancouver, ISO, and other styles
16

Sina, Md Ibne. "Satellite Image Processing with Biologically-inspired Computational Methods and Visual Attention." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23122.

Full text
Abstract:
The human vision system is generally recognized as being superior to all known artificial vision systems. Visual attention, among many processes that are related to human vision, is responsible for identifying relevant regions in a scene for further processing. In most cases, analyzing an entire scene is unnecessary and inevitably time consuming. Hence considering visual attention might be advantageous. A subfield of computer vision where this particular functionality is computationally emulated has been shown to retain high potential in solving real world vision problems effectively. In this monograph, elements of visual attention are explored and algorithms are proposed that exploit such elements in order to enhance image understanding capabilities. Satellite images are given special attention due to their practical relevance, inherent complexity in terms of image contents, and their resolution. Processing such large-size images using visual attention can be very helpful since one can first identify relevant regions and deploy further detailed analysis in those regions only. Bottom-up features, which are directly derived from the scene contents, are at the core of visual attention and help identify salient image regions. In the literature, the use of intensity, orientation and color as dominant features to compute bottom-up attention is ubiquitous. The effects of incorporating an entropy feature on top of the above mentioned ones are also studied. This investigation demonstrates that such integration makes visual attention more sensitive to fine details and hence retains the potential to be exploited in a suitable context. One interesting application of bottom-up attention, which is also examined in this work, is that of image segmentation. Since low salient regions generally correspond to homogenously textured regions in the input image; a model can therefore be learned from a homogenous region and used to group similar textures existing in other image regions. Experimentation demonstrates that the proposed method produces realistic segmentation on satellite images. Top-down attention, on the other hand, is influenced by the observer’s current states such as knowledge, goal, and expectation. It can be exploited to locate target objects depending on various features, and increases search or recognition efficiency by concentrating on the relevant image regions only. This technique is very helpful in processing large images such as satellite images. A novel algorithm for computing top-down attention is proposed which is able to learn and quantify important bottom-up features from a set of training images and enhances such features in a test image in order to localize objects having similar features. An object recognition technique is then deployed that extracts potential target objects from the computed top-down attention map and attempts to recognize them. An object descriptor is formed based on physical appearance and uses both texture and shape information. This combination is shown to be especially useful in the object recognition phase. The proposed texture descriptor is based on Legendre moments computed on local binary patterns, while shape is described using Hu moment invariants. Several tools and techniques such as different types of moments of functions, and combinations of different measures have been applied for the purpose of experimentations. The developed algorithms are generalized, efficient and effective, and have the potential to be deployed for real world problems. A dedicated software testing platform has been designed to facilitate the manipulation of satellite images and support a modular and flexible implementation of computational methods, including various components of visual attention models.
APA, Harvard, Vancouver, ISO, and other styles
17

Sanson, Fabrice. "Génération et optimisation d'harmoniques d’ordres élevés portant un moment angulaire orbital pour l'injection dans un plasma de laser X-UV." Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPASP026.

Full text
Abstract:
Ce manuscrit présente le travail de thèse CIFRE/Amplitude réalisé pour mettre en place sur la ligne XUV de LASERIX une expérience de génération d'harmoniques par un faisceau infrarouge de pompe portant un moment angulaire non nul produit par ajout d'une lame de phase. L'originalité de notre démarche a été de générer les harmoniques dans une cellule de gaz relativement longue (de l'ordre de 10mm) et de caractériser les vortex optiques de l’harmonique 25 par un Hartmann Extreme Ultraviolet. Nous avons démontré que la sensibilité du détecteur et la fiabilité du traitement logiciel des données permettait de vérifier que l'harmonique 25 porte typiquement un moment angulaire de 25, conforme aux prédictions. L'analyse plus poussée des données expérimentales a permis de mettre en évidence le caractère intrinsèquement multimode des faisceaux produits. Elle a aussi permis de montrer le rôle de l'astigmatisme résiduel, même très faible du faisceau infrarouge de pompe dans la forme bi-lobale des vortex harmoniques produits. Forme que l'on a pu étudier et corriger grâce à une boucle de correction du front d'onde du laser de pompe. Le travail s'appuie sur des codes de propagation et de diffraction de faisceaux portant des moments angulaires non nuls, que ce soit dans l'XUV ou l'infrarouge. Ils permettent de quantifier le caractère multimode, en termes de modes LG, des faisceaux infrarouges traversant une lame de phase supposée d'abord parfaite, puis réelle. Puis en utilisant le modèle de l'atome unique de la GHOE que le processus non linéaire non perturbatif induisait intrinsèquement de nouveaux modes LG radiaux. L'objectif de tout ce travail pour l'équipe LASERIX était de démontrer la capacité d'un plasma amplificateur de type laser X pompé en cible solide à amplifier un vortex harmonique à la bonne longueur d'onde, tout en conservant sa structure modale et en tous cas la charge portée par le faisceau. Une collaboration avec Eduardo Oliva de Madrid qui réalise des simulations de type Maxwell Bloch montre que cela est possible du point de vue de la physique fondamentale de l'amplification dans ce domaine de longueurs d'onde
This document presents the CIFRE/Amplitude thesis work carried out to set up on the LASERIX XUV line an experiment of high harmonic generation by a pump infrared beam carrying a non-zero orbital angular momentum produced by adding a phase plate on the beam path. The originality of our approach was to generate the harmonics in a relatively long gas cell (around 10mm) and to characterize the optical vortices of harmonic 25 by a Extreme Ultraviolet Hartmann. We demonstrated that the sensitivity of the detector and the reliability of the software processing of the data made it possible to verify that harmonic 25 typically carries an orbital angular momentum of 25, as theoretically predicted. Further analysis of the experimental data allowed us to quantitatively demonstrate the intrinsically multimode nature of the produced beams. I have therefore detailed the different methods of analysis proposed in the literature, I could compare their reliability and their relevance to describe the physical phenomenon at work. I also studied in detail the robustness and convergence of the analytical methods applied to beams with typical orbital angular momenta as high as l=25. The analysis of the data allowed me to show the role of even very weak residual astigmatism contained in the pump infrared beam to produce the bi-lobal shape of the vortices. This characteristic shape was also obtained by other teams. One way to regain a truly annular shape is to set up an active optimization loop of the pump laser wavefront. I have also developed propagation and diffraction calculations of beams carrying non-zero orbital angular momenta, whether in EUV or infrared. This allowed me to quantify the multimode character, in terms of LG modes, of the infrared beams passing through a phase plate that was first assumed to be perfect, then real. Then I showed using the single atom model for harmonic generation that this non-linear, non-perturbative process intrinsically induced new radial LG modes. Finally, the objective of all this work for the LASERIX team was to demonstrate the ability of an X-ray laser amplifier plasma pumped from a solid target to amplify a harmonic vortex at the right wavelength, while maintaining its modal structure and in any case the charge carried by the beam. A collaboration with Eduardo Oliva from Madrid, who carries out Maxwell Bloch simulations, shows that this is possible from the point of view of the fundamental physics of the amplification in this wavelength range
APA, Harvard, Vancouver, ISO, and other styles
18

Marigliano, Giulia. "Descrittori meteo-climatici del regime di frequenza dei massimi annuali di precipitazione sub-giornaliera osservati in Emilia-Romagna." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.

Find full text
Abstract:
Sulla base del modello proposto da Di Baldassarre et al. (2006), che utilizza la precipitazione media annuale (MAP) come proxy della posizione geografica, l’elaborato di Tesi si è posto come obiettivo quello di ricercare ulteriori proxy in grado di fornire una migliore previsione degli eventi estremi di precipitazione, in modo da migliorare la capacità di previsione del modello. Sono stati valutati il 95° percentile delle cumulate annue di precipitazione e il 95° percentile dei dati di precipitazione giornaliera, e per il calcolo degli L-momenti (v. Hosking e Wallis, 1993, 1997), momenti statistici di largo impiego in campo idrologico. È stato poi analizzato il legame tra ciascun proxy climatico e gli L-momenti, con lo scopo di valutare se, sulla base del modello proposto da Di Baldassarre et al. (2006) si ottengono significativi benefici. Ai fini dell’analisi sono stati impiegati due dataset, entrambi forniti da ARPAE (Agenzia regionale per la prevenzione, l'ambiente e l'energia dell´Emilia-Romagna): il dataset AMS fornisce i dati relativi alle serie dei massimi annuali di precipitazione per durate sub-giornaliere e sub-orarie, relativi alle stazioni pluviometriche che si trovano all’interno di bacini idrografici situati nell’area di pertinenza di ARPAE, per il periodo 1921-2018; il dataset PrecClima è un dataset climatico giornaliero di precipitazioni che copre tutto il territorio regionale (e dintorni) dal 1961 al 2018, ottenuto da ARPAE mediante interpolazione spaziale su una griglia regolare a partire dai valori rilevati dalla rete delle stazioni meteorologiche storiche. Esaminando i risultati ottenuti si può affermare che l’utilizzo di un proxy che fa riferimento a valori estremi, quali AP95 e DP95, non porta a miglioramenti significativi rispetto all’utilizzo di un proxy che tiene conto di un valore medio, in questo caso il MAP.
APA, Harvard, Vancouver, ISO, and other styles
19

Abdallah, Abdallah Sabry. "Investigation of New Techniques for Face detection." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/33191.

Full text
Abstract:
The task of detecting human faces within either a still image or a video frame is one of the most popular object detection problems. For the last twenty years researchers have shown great interest in this problem because it is an essential pre-processing stage for computing systems that process human faces as input data. Example applications include face recognition systems, vision systems for autonomous robots, human computer interaction systems (HCI), surveillance systems, biometric based authentication systems, video transmission and video compression systems, and content based image retrieval systems. In this thesis, non-traditional methods are investigated for detecting human faces within color images or video frames. The attempted methods are chosen such that the required computing power and memory consumption are adequate for real-time hardware implementation. First, a standard color image database is introduced in order to accomplish fair evaluation and benchmarking of face detection and skin segmentation approaches. Next, a new pre-processing scheme based on skin segmentation is presented to prepare the input image for feature extraction. The presented pre-processing scheme requires relatively low computing power and memory needs. Then, several feature extraction techniques are evaluated. This thesis introduces feature extraction based on Two Dimensional Discrete Cosine Transform (2D-DCT), Two Dimensional Discrete Wavelet Transform (2D-DWT), geometrical moment invariants, and edge detection. It also attempts to construct a hybrid feature vector by the fusion between 2D-DCT coefficients and edge information, as well as the fusion between 2D-DWT coefficients and geometrical moments. A self organizing map (SOM) based classifier is used within all the experiments to distinguish between facial and non-facial samples. Two strategies are tried to make the final decision from the output of a single SOM or multiple SOM. Finally, an FPGA based framework that implements the presented techniques, is presented as well as a partial implementation. Every presented technique has been evaluated consistently using the same dataset. The experiments show very promising results. The highest detection rate of 89.2% was obtained when using a fusion between DCT coefficients and edge information to construct the feature vector. A second highest rate of 88.7% was achieved by using a fusion between DWT coefficients and geometrical moments. Finally, a third highest rate of 85.2% was obtained by calculating the moments of edges.
Master of Science
APA, Harvard, Vancouver, ISO, and other styles
20

Teixidó, Roman Miguel. "A cotangent bundle Hamiltonian tube theorem and its applications in reduction theory." Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/288376.

Full text
Abstract:
The Marle-Guillemin-Sternberg (MGS) model is an extremely important tool for the theory of Hamiltonian actions on symplectic manifolds. It has been extensively used to prove many local results both in symplectic geometry and in symmetric Hamiltonian systems theory. It provides a model for a tubular neighborhood of a group orbit and puts in normal form the group action and the symplectic structure. The main drawback of the MGS model is that it is not explicit. Only it existence and main properties can be proved. Moreover, for cotangent bundles, this model does not respect the natural fibration. In the first part of the thesis we build an MGS model specially adapted to the cotangent bundle geometry. This model generalizes previous results obtained by T. Schmah for orbits with fully-isotropic momentum. In addition, our construction is explicit up to the integration of a differential equation on G. This equation can be easily solved for the groups SO(3) or SL(2), hence giving explicit symplectic coordinates for arbitrary canonical actions of these groups on any cotangent bundle. In the second part of the thesis we apply this adapted MGS model to describe the structure of the symplectic reduction of a cotangent bundle. We show that the base projection of any momentum leaf is a Whitney stratified space. Moreover, we can refine the orbit-type stratification of the symplectic reduced space so that each piece is a fibered space. We prove that each of those pieces is endowed with a constant rank presymplectic form and that there is always one unique piece which is open and dense. Furthermore, this maximal piece is symplectomorphic to a vector subbundle of a certain cotangent bundle.
El model de Marle-Guillemin-Sternberg (MGS) és una eina extremadament important per la teoria de les accions Hamiltonianes en varietats simplèctiques. Ha estat utilitzada per provar molts resultats te tipus local tant en geometria simplèctica com en la teoria de sistemes Hamiltonians simètrics. Proporciona un model per un entorn tubular de una òrbita de la acció de forma que fica en forma normal tant l'acció del grup com l'estructura simplèctica. El principal problema del model MGS és que no és explícit. Només es poden provar la seva existència i les seves propietats principals. Per altra banda, en el cas de que la varietat sigui un fibrat cotangent la el model MGS no respecta la fibració natural. En la primera part de la tesis construïm un model MGS especialment adaptat a la geometria dels fibrats cotangents. Aquest model generalitza els resultats obtinguts per T. Schmah per òrbites amb moment completament isotròpic. Addicionalment, la nostra construcció és explicita excepte per la integració d'una equació diferencial sobre el grup G. Aquesta equació pot ser solucionada de forma explícita per els grups SO(3) o SL(2), per tant podem donar explícitament coordenades simplèctiques per a accions arbitraries d'aquests grups sobre qualsevol fibrat cotangent. En la segona part de la tesis apliquem aquest model MGS cotangent per descriure l'estructura de les reduccions simplèctiques de fibrats cotangents. Mostrem que la projecció sobre la base de una fulla de moment és un espai estratificat de Whitney. També podem refinar l'estratificació de l'espai simplèctic reduït de forma que cadascuna de les peces és un espai fibrat. Demostrem que cadascuna d'aquestes peces està dotada d'una forma pre-simplèctica de rang constant i que sempre hi ha una única peça que es oberta i densa en l'espai reduït. A més aquesta peca maximal és simlpectomorfa a un subfibrat vectorial de un cert fibrat cotangent.
APA, Harvard, Vancouver, ISO, and other styles
21

Reuven, Genuyah S. "Commission of Two Narratives of the Psyche: Reading Poqéakh in Nella Larsen’s Quicksand and Ralph Ellison’s Invisible Man." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2019. http://digitalcommons.auctr.edu/cauetds/170.

Full text
Abstract:
This study focuses on the novels of Quicksand by Nella Larsen and Invisible Man by Ralph Ellison to explore the phenomenon of poqéakh (פֹּקֵחַ) through the fictionalized lived experiences of their protagonists, Helga Crane and invisible man. Each novelist’s representation of poqéakh offers a portrait of the protagonists’ psyches. The narratives reveal an unsettling truth for the protagonists, who are members of a population often targeted, stigmatized, and fashioned or re-fashioned by Americans and various environs in American society, that they must assimilate—not only their bodies, but their psyches too to fit the “white man’s pattern” (Larsen 4). Their realities inform them that non-conformity and/or developing or utilizing their intellect is disadvantageous—perceiving is unfavorable. Each protagonist learns that she and he will not only be limited by their imaginations or abilities, but also by persons and constructs within American society keeping them witless and amenable. The environs presented in forms such as schools, jobs, even people who prepare each protagonist to accept all and any disparity (inequality and inequity), they are made to be persistently and surreptitiously instructive. As such, these environs are always educating (or training), always molding the psyches of the protagonists to live within a frame—the construct (American society). These ever informing boundaries thoroughly acquaint each protagonist on “how to scale down [their] desires and dreams so that they will come within reach of possibility” (Thurman 115). Poqéakh leads Helga Crane to perceive the boundaries while it prevents the invisible man from returning to unblissful ignorance, thus, for him, providing momentary periods of lucidity. This study utilizes a qualitative research design and method, and relies on phenomenological theory to successfully analyze the novels and explicate on the representations of poqéakh. As this study will illustrate, Larsen and Ellison offer as representative via their novels two narratives of the diasporic psyche (mind), wherein their protagonists’ experiences of poqéakh lead to some unmitigated facts and disturbing truths about their reality.
APA, Harvard, Vancouver, ISO, and other styles
22

Cheung, Anthony Hing-lam. "Design and implementation of an Arabic optical character recognition system." Thesis, Queensland University of Technology, 1998. https://eprints.qut.edu.au/36073/1/36073_Cheung_1998.pdf.

Full text
Abstract:
Character recognition is not a difficult task for humans who repeat the process thousands of times every day as they read papers or books. However, after more than 40 years of intensive investigation, there is still no machine that can recognize alphabetic characters as well as humans. Optical Character Recognition (OCR) is the process of converting a raster image representation of a document into a format that a computer can process. It involves many sub-disciplines of computer science including digital image processing, pattern recognition, natural language processing, artificial intelligence, and database systems. Applications of OCR systems are broad and include postal code recognition in postal departments, automatic document entries in companies and government departments, cheque sorting in banks, machine translation, etc. The objective of this thesis is to design an optical character recognition system which can recognize Arabic script. This system has to be: 1) accurate: with a recognition accuracy of 953; 2) robust: able to recognize two different Arabic fonts; and 3) efficient: it should be a real time system. This proposed system is composed of five image processing processes: 1) Image Acquisition; 2) Preprocessing; 3) Segmentation; 4) Feature Extraction; and 5) Classification. The recognized results are presented to users via a window-based user-interface. Thus, they can control the system, recognize and edit documents by a click on the mouse button. A thinning algorithm, a word segmentation algorithm and a recognition based character segmentation algorithm for Arabic script have been proposed to increase the recognition accuracy of the system. The Arabic word segmentation algorithm successfully segments the horizontally overlapped Arabic words, whereas the recognition-based character segmentation algorithm replaces the classical character segmentation method and raises the level of accuracy of recognition of the proposed system. These blocks have been integrated. Results to test the requirements of accuracy, robustness and efficiency are presented. Finally, some extensions to the system have also been proposed.
APA, Harvard, Vancouver, ISO, and other styles
23

Simmeborn, Fleischer Ann. "”Man vill ju klara sig själv” : Studievardagen för studenter med Asperger syndrom i högre utbildning." Doctoral thesis, Högskolan för lärande och kommunikation, Högskolan i Jönköping, HLK, CHILD, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-20984.

Full text
Abstract:
Sammanfattning Sedan början av 2000-talet har det skett en markant ökning av studier gällande barn och ungdomar och Autism. Dock är det så att den mesta forskningen fortfarande är inom det medicinska området. Endast ett fåtal av studierna rör vuxna med Asperger syndrom (AS) som studerar på högskola/universitet. Samtidigt sker en ökning av personer med AS som söker högre utbildning såsom högskola/universitet, vilket gör forskning gällande personer med diagnosen AS högaktuell. Antalet studenter med kognitiva funktionshinder, dit AS räknas, som sökt pedagogiskt stöd på högskola/universitet i Sverige, har ökat från 1 427 studenter 2010 till 1 943 studenter 2012. När man studerar på högskola/universitet så finns det pedagogiska stöd att tillgå, och till vardagen finns Lagen om stöd och service till vissa funktionshindrade (LSS) och Socialtjänstlagen (SoL) som personer med AS har möjligheter att söka stöd genom.  Personer med AS kan ibland ha svårt att utnyttja stödsystem som kräver att man själv identifierar och uttalar sina behov av stöd. Denna avhandling fokuserar på personer med AS i högre utbildning och stöd. I doktorsavhandlingen ingår två studier: Studie I som är en fallstudie och Studie II, som är en enkätstudie. Bindningspunkten för studierna är studenter med AS som fått pedagogiskt stöd i sin utbildning vid högskola/universitet. Studie I Studie I består av en fallstudie (Merriam, 1994, 2009; Patton, 2002) som innefattade tre fall. Studien redovisas i artikel I och II, där artikel I bygger på studenternas berättelser och artikel II på anhörigas och samordnares berättelser. Insamlandet av data har byggt på berättelser genom samtal (Doecke, Brown, & Loughran, 2000; Hydén & Brockmeier, 2008; Johansson, 2005; Skott, 2004). Valet av berättelser som metod, innebär att man som forskare fokuserar på att få möjligheter att lära känna en annan person, få kunskap om denna persons erfarenheter, känslor och förväntningar. För att säkerhetsställa undersökningens validitet, användes triangulering mellan tre olika källor: intervjuer med studenter, anhöriga och samordnare. Urvalet av högskola/universitet gjordes med avsikten att inkludera högskolor/universitet från olika delar av Sverige, olika stora högskolor/universitet med olika studieinriktningar. Syfte med Studie I är att undersöka hur studenter med AS i högre utbildning beskriver och förstår sin livshistoria och sin studievardag, vilket redovisas i artikel I och i kappans resultat. Anhöriga är en central resurs för personer med AS. Därför undersöks i den andra artikeln hur anhöriga uppfattar sina barns eller syskons studier och det stöd de tidigare fått i skolan och på högskola/universitet. I artikeln redovisas även hur man upplever det pedagogiska stöd som högskola/universitet erbjuder. Samordnare för studenter med funktionshinder har en central roll i vilka pedagogiska stöd som beslutas att students ska få, därför är det också av vikt att undersöka hur samordnare beskriver den stödverksamhet som finns på högskola/universitet. Även detta redovisas i andra artikeln samt i kappans resultat. Vid insamling av data var fokus på studenternas berättelser om sin studievardag och hur de beskrev sina skolerfarenheter, från förskola fram till högskola/universitet samt hur de såg på sin framtid (Hydén & Brockmeier, 2008). Vid samtalen med anhöriga och samordnare använde forskaren sina yrkeserfarenheter som berör AS, diagnossättande, mediciner, lagar och forskning samt personliga erfarenheter. De anhöriga som intervjuades bestämdes av studenterna och bestod av en mamma, en pappa och en syster. Samordnarna bestod av de som arbetade på den högskola/universitet som studenten studerade på. Samtalsmanual har använts som stöd vid varje samtal. Totalt har tolv samtalsmanualer använts. Samtalens längd för studenterna varierade mellan 1 timma och 4 minuter till 4 timmar och 50 minuter. Samtalens längd varierade mellan 1 timma och 10 minuter till 3 timmar och 23 minuter för de anhöriga. Samtalens längd varierade mellan 1 timma och 13 minuter till 3 timmar och 40 minuter för samordnare. Varje samtal anpassades helt efter varje anhörigs och samordnares intresse av att vilja samtala.  De tre fallbeskrivningarna omfattade femton transkriberade samtal: tre vardera för varje student, en för vardera anhörig och en för vardera samordnare. Första steget i analysen var att forskaren läste igenom det transkriberade materialet kring varje student upprepade gånger så att en känsla för helheten uppstod. Vid tredje genomläsningen gjordes noteringar i form av nyckelord som beskrev innehållet. Därefter plockades de meningar ut som innehöll information som byggde på nyckelorden och var relevanta för frågeställningarna. Den omgivande texten togs med så att sammanhanget kvarstod, det bildade meningsbärande enheter. De meningsbärande enheterna i samtalstexterna kondenserades i syfte att korta ner texten men ändå behålla innehållet. De kodades därefter och grupperades i kategorier som återspeglade det centrala budskapet i samtalen i relation till studenterna. Samma process gjordes med de anhörigas och samordnarnas transkriberade material. I Studie I framkom det att studenter med AS ofta behöver stöd i sin studievardag, det vill säga både i studierna och i vardagslivet, för att klara sina studier. Personer med AS har en kognitiv funktionsnedsättning som kan ge svårigheter i deras studievardag, och de har ofta en nedsatt förmåga att beskriva sina svårigheter och kan därför inte alltid redogöra för vilka behov de har. När man söker stöd bygger ansökan på att man själv kan beskriva sina behov av stöd och framför allt välja bland de stöd som finns utifrån det behov och de svårigheter man har, det vill säga man ges en stor valfrihet. För studenter med AS kan detta bli till en stor svårighet då de ofta inte själva vet vilka stöd de har behov av och vad de olika stöden skulle innebära för de studiesvårigheter de har. Studenterna i studierna angav att när de fick stöd hade de svårt att förstå hur stödet skulle fungera och hur det skulle kunna förbättra deras studier, och att det pedagogiska stödet i stället blev till ytterligare ett hinder, som tog tid och fokus från studierna. Stödinsatsen med vidhängande valfrihet kan ses som ett uttryck för en ekvifinalitet: stödsystemet har designats för att ge olika funktionshindrade samma möjlighet, och utgångspunkten är att valfrihet är bra för alla. Många av studenterna har beskrivit att de känner sig socialt begränsade och har kommunikationssvårigheter och de upplever att de är stigmatiserade och känner sig alienerade. I analysen av studenternas beskrivning av sin livshistoria och studievardag framstod två teman, Kamp och Utanförskap. Anhöriga beskrev att kraven på fokusering, både på vardags- och studentaktiviteter, blev övermäktiga för deras barn eller syskon. De kunde se att deras barn eller syskon hade svårigheter med att planera inköp av exempelvis mat, att laga mat, att tvätta och sköta andra vardagsrutiner i hemmet. Samordnare för studenter med funktionshinder utryckte att även om de kunde se att studenter hade problem med vardagsrutiner i hemmet,  kunde de inte ge något stöd för detta. De hade också svårt att erbjuda stöd i vissa studietekniska frågor. Samordnarna beskrev att det är svårt att ställa frågor om en students funktionshinder, diagnos och livssituation och att det är svårt att få grepp om vilket stöd som skulle kunna bli bra för varje enskild student. Sammantaget så har det framkommit att studenter med AS har behov av både pedagogiskt stöd och stöd i vardagsrutiner och det framkom också i studierna att de olika stöden behöver samordnas så att studenter med AS erhåller stöd i hela studievardagen. Det framkom också att det finns behov av ett kunskaps- och kommunikationsverktyg för framför allt samordnare och studenter. Detta verktyg skulle kunna användas av samordnare och student så att en tydlig agenda upprättas och följs vid samtalen och beslut om vad eller vilka pedagogiska stöd som studenten skulle kunna få som stöd i studierna. Studie II Studie II består av en enkätstudie, bestående av 55 frågor med både öppna och slutna svarsalternativ, riktat till studenter med AS, studenter med rörelsehinder (RH) och studenter med hörselnedsättning (HN). Även i denna studie står studenter med AS i fokus, men med mer generell frågeställningar: Hur beskriver studenter med AS, RH och HN upplevda problem, erhållet stöd och upplevt stöd? Finns det skillnader och likheter mellan dessa tre grupper av studenter? Resultatet redovisas i artikel III samt kappans resultat. Syftet med studie II är också att undersöka vilka karaktäristika för studenter med AS som kan identifieras och bedömas som så viktiga att de med stöd av Internationella klassifikation för funktionstillstånd, funktionshinder och hälsa kan behöva ingå i ett code set. Resultatet redovisas i artikel IV samt i kappans resultat. Under arbetet med Studie I uppkom funderingar på om det fanns studentgrupper med andra funktionshinder som har samma erfarenheter som studenter med AS. Därför utökades urvalet till studenter RH och HN. Studie II var beskrivande med en mixed methods design. Den första delen hade en huvudsakligen kvantitativ ansats med data insamlade via en enkät. Till enkätstudien tillfrågades alla högskolor/universitet om de var intresserade att delta i undersökningen. Det var 14 samordnare på 12 högskolor/universitet som tackade ja till att medverka och de tillfrågade sedan de studenter som kunde vara aktuella att medverka i undersökningen. Respondenter blev 34 studenter som studerade vid 12 svenska högskolor/universitet, 16 studenter med AS, 11 med RH och 7 med HN. Eftersom endast 34 studenter kunde rekryteras betraktas detta som en pilotstudie. Den kan ge en första antydan om hur studievardagen upplevs av studenter med funktionshinder och om det finns någon skillnad mellan de tre undersökta grupperna av studenter när det gäller svårigheter och behov av stöd.  I den andra delen av studie II togs ett första steg till ett code set, en början till ett kommunikationsverktyg, det vill säga en samtalsmanual mellan samordnare och studenter, samt som information till anhöriga. Analysen hade en deduktiv, kvalitativ ansats. Data från flera olika källor, bland annat enkäterna, analyserades och jämfördes genom att innehållet länkades till ICF-koder. Avsikten var att identifiera preliminärt innehåll i ett code set.   Analysen av enkäterna var kvantitativ så långt materialet medgav det, och grupperna jämfördes genom så kallad korstabulering. Nästa steg i analysen (Code set förberedelsen) fokuserade endast på studenter med AS. Information i enkäten länkades kvalitativt deduktivt till ICF tillsammans med information från fem olika källor som representerar olika perspektiv: 1) Studenters egna beskrivningar, 2) Internationella diagnosklassifikationer, 3) Nationella policy-dokument för högre utbildning, 4) Hälso- och sjukvården, 5) Brukarorganisationen Autism och Aspergerförbundet. De fem olika källorna innefattade tio dokument som valts utifrån inklusionskriterierna målgruppen AS, åldersgruppen unga vuxna, undervisning/utbildnings-krav för högre utbildning, insatser/behov av stöd samt nationella/internationella källor med anknytning till målgruppen. Syftet var att integrera flera olika perspektiv på behov av stöd i studievardagen för studenter med AS. Därmed kunde en första lista med ICF-koder identifieras som underlag till ett code set för studenter med AS på högskola/universitet. I Studie II framkom det att även om studenter med AS verkade rapportera samma svårigheter, varierade förklaringarna som gavs till problemen mellan grupperna. När det gällde förklaringar verkade det för studenter med AS vara kopplat till kognitiva svårigheter medan det för studenter med rörelsehinder (RH) och hörselnedsättning (HN) var kopplat till fysiska svårigheter. På ytan kan de olika gruppernas svårigheter alltså se lika ut och de kommer då att erbjudas samma pedagogiska stöd från sin högskola/universitet. I enkätsvaren framhölls att det var väldigt viktigt för studenterna att kunna få ett arbete efter avslutade studier för att därmed få möjligheter att kunna försörja sig och leva ett vanligt liv som alla andra. Innan dess måste dock studierna genomföras och i den studievardag som beskrevs, talades det om kamp och utanförskap. Några av de erfarenheter som lyftes fram av alla grupperna studenter var, stress och koncentrationssvårigheter, trötthet, och social begränsning . I Studie II framkom alltså samma problem som i Studie I med att tydligt uttrycka svårigheter och behov. Det indikerar att det finns behov av ett kunskaps- och kommunikationsverktyg för samtal mellan samordnare och studenter. Ett ICF baserat code set för högre utbildning för studenter med AS skulle kunna vara ett sådant verktyg. Ett code set består av ett antal kategorier från ICF och beskriver de svårigheter som studenter med AS kan ha och som kan bilda en checklista att arbeta utifrån vid samtal, planering av stöd och information till annan personal. Det ska vara så tydligt att det kan ges till studenten i förväg så att studenten får möjligheter att förbereda sig på vad samtalet och mötet innebär. Avslutningsvis har det framkommit att om studenter med AS ska bli inkluderade i högre utbildning och om uteslutningsmekanismer såsom stigmatisering och alienation ska motverkas, krävs det troligen tydligt strukturerade individuella lösningar: Stödet ska ge en öppning mot en multifinalitet istället för den ekvifinalitet som idag råder vid erbjudande av stöd. Lösningar och stöd ska inte bara vara baserade på en diagnos, utan på en analys av varje students upplevda svårigheter sett ur perspektivet hela studievardagen. Först då kan stöden bli till de verkligt frigörande möjligheter som är avsikten.
Summary Since the beginning of the 21st century there has been a significantly increased number of studies on children and young adults with Autism Spectrum disorder (ASD). Most of this research falls within the domain of Medicine and only limited number of studies focusses on adults with Asperger Syndrome (AS) as students at university. Considering that there is an increase in numbers of individuals diagnosed with AS attending tertiary education researching this group of individuals is both timely and opportune. The number of students with cognitive disabilities, such as AS, seeking assistance to help their study efforts along at universities has increased in Sweden from 1427 students in 2010 to 1943 students in 2012. It should be noted that support in everyday student-life is guaranteed by legislation (that is, by Social Service Act (SoL) and  Support and Service for Persons with Certain Functional Impairments (LSS)) and that this same guarantee is valid also of studying at university. However, individuals with AS may at times have difficulty using available support, since they must identify their own needs and also communicate the nature of their need. This doctoral thesis is focusing on individuals with AS in need of such support in tertiary education. The thesis is comprised by two main studies: Study I, which is a case study, and Study II, which is a survey. Their common denominator is students with AS who have received legally guaranteed support as university students. study I The first study is a case study of three cases. This research is reported in the two first articles of the four articles comprising the entire thesis. The first article focusses on student narratives, whereas article two rather focusses on the accounts of next of kin as well as those of university coordinators I charge of assisting students in need. Data were collected through conversations.  The particular choice of method allows for the researcher to acquire more intimate knowledge of the participants learning of their experiences, feelings and expectations. To secure validity the data from students, next of kin and university coordinators was triangulated. Number and type of universities included in the study were sampled on the principle that there should be included universities from different parts of Sweden, of different sizes and with different academic profiles. The aim of Study I was to investigate how students with AS, as students in tertiary education, describe their life history and their everyday student-life. This particular focus is reported in the first article. Next of kin are central to individuals with AS. In the second article therefore, the perceptions of next of kind and how these understand their children’s or sibling’s university studies as well as the available support for them are accounted for. Also university coordinators in charge of study assistance at universities are of considerable importance. They decide the manner of support provided. It is therefore important to also describe how these outline and assess the existing support. This too is the focus of the second article. During data collection the focus was on students’ narratives of their everyday student-life at university as well as how they experienced their entire education experience from pre-school and to tertiary education. The views of their own future was also an issue that was addressed. The conversations with participants were facilitated by the researcher in terms of conveying previous research results on the nature of AS individuals’ experience of university education; of the researcher’s professional experiences of the situation and also of herself being next of kin to an individual with an AS diagnosis. As a means of helping conversations with next of kin and coordinators along the researcher used her own professional experience in relation to AS individuals, diagnosing, medication, legal framework, previous research and personal experience. Which next of kin to be interviewed - a mother, father and a sibling - was decided by the participating students themselves. For each university there is generally only one coordinator. These participated in the study. A conversation manual has been used as support for each data collecting conversation. In all, twelve such manuals have been used. The length of the conversations with participating students varied between 1 hour and 4 minutes to 4 hours and 50 minutes. Conversations with next of kind varied between 1 hour and 10 minutes to 3 hours and 23 minutes and for coordinators the duration varied between 1 hour and 10 minutes to 3 hours and 40 minutes. Every conversation was entirely adapted to each participating individual and their willingness to converse about the subject matter. The three cases were comprised of 15 transcribed conversations: three for each student, one for each next of kin, and also one for each university coordinator. As a first step in analysing the data the researcher read transcriptions multiple times to lay foundations for an understanding of entirety. During the third read notes were taken in the form of key words significant to content. Extraction of sentences containing these keywords followed. Key words were always significant in relation to the research questions. The surrounding text was taken too in order to preserve context. Together the keywords, the sentences and the surrounding contexts constituted meaningful units of text. These units, in every transcribed conversation, were condensed in order to shorten texts but still maintain the essence of its meaningful content. The condensed text units were coded and grouped in categories that reflected the essential and meaningful content of the conversations. Data culled from the next of kin and the coordinators were submitted to the same process of data analysis. Results showed that students with AS often do need assistance at university both in terms of studying as well as in their daily life off campus in order to manage an existence as students. Individuals with AS however have a cognitive disability that may challenge their efforts as students. In addition, they have difficulties describing their problems and often find it hard to define which needs for assistance they do have. When applying for assistance students are required to specify their special needs of support, and more importantly, also choose what kind of assistance they require. In other words, they are given a considerable freedom of choice. To students with AS this presents an obstacle. They often do not know what kind of assistance they require and what a certain kind of support would entail. Participating students reported that it was difficult for them to grasp how the support would actually function and how it would improve their studying. Instead, the possibility of acquiring support became yet another problem which made studying even more difficult for them. The availability of support with the accompanying freedom of choice as to the manner and content of the support may be seen as an expression of equifinality. That is, the support system has been designed to provide each disabled individual with equal opportunity of attaining support. The basic value underpinning the support system is that freedom of choice is valuable to each and every one. However, many students with AS have reported that they feel socially limited, alienated even stigmatised and that they communicate poorly. In analysing the narratives of students’ life histories as well as their everyday student-life as students two themes emerged: Struggle and Alienation. The next of kin described the demands of focus, both on and off campus, to be overwhelming for their children or siblings. They observed difficulties with planning ahead to shop for groceries, to do laundry, to cook or to do sundry domestic chores at home. University coordinators understood that students had such problems off campus but could not offer assistance relating to off-campus difficulties. However, they also found it difficult to offer these students assistance pertaining to certain aspects of student life. They found it tricky to pose questions regarding students’ disability, diagnosis and general life situation. It was thus a problem for them to acquire an understanding of what kind of assistance that would be suitable for each individual student. In all, the research clearly showed that students with AS are in need of both educational support and everyday student-life support and that these two aspects of assistance need to be coordinated. Results also suggested the need of a tool for knowledge and communication, especially for students and university coordinators. Such a tool would facilitate the communication and would serve as a basis in deciding what kind of remedial action that needs to be taken for the benefit of students with AS. Study II The second study was operationalized as a survey study employing a questionnaire consisting of 55 questions of which some were open-ended. This instrument was administered to students with Asperger Syndrome (AS), to students with mobility impairment (MD) and to students with impaired hearing (HD). Note that abbreviations relate to the Swedish nomenclature for these disabilities. This study also focussed on students with AS but addressed more general questions: How do students with AS, MD and HD describe problems, provided support and the experience of being given support? Are there similarities or differences between these three groups of students? This research is presented in the third article of the doctoral thesis. The aim of the second study was also to explore what characteristics of students with AS could be identified as particularly important in an effort to classify them as a code set with the framework of the International Classification of Functioning, Disability and Health (ICF). A code set consists of a number of categories derived from the ICF classification system. It describes the type and nature of difficulties that for example students with AS may experience, thus constituting a checklist from which to work when university coordinators and students discuss the nature and manner of support needed and then succinctly be able to convey such information to other relevant staff. Such a tool will need to be straight-forward and given to students prior to meeting the coordinators in order to help students prepare for the meeting being fully informed of its content and purpose. The result of this exploratory second study is presented in the fourth article.  As the study of AS student cases progressed there arose questions regarding other students with different kinds of disability also. Do they have the same or similar problems? For this reason a second study was launched and mobility impaired students (MD) and hearing impaired students (HD) were included also. This study was descriptive but operationalized as a mixed methods design. The first part of it consisted of a quantitatively based questionnaire. All Swedish universities and higher education institutions were invited to take part. Fourteen coordinators from 12 universities accepted. They in turn asked students to take part. In all, 34 students decided to participate. These were divided into the following categories: 16 (AS), 11 (MD) and 7 (HD). Due to the relatively low number of participants the study is best considered to be a pilot study. It could be suggestive in reference to how everyday student-life on campus might be experienced by students with different disabilities and whether there are differences between the three studied groups in need of support. In the second part of the second study a first step was taken towards creating a code set; the beginning of a communication tool serving as a conversation manual between coordinator and students. The analysis of the data was qualitative but deductive. Data from several sources, including the questionnaire, were analysed, compared and linked to ICF-codes in order to identify a tentative content of a potential code set. The data culled by the questionnaires was first cross-tabulated. The next phase of the analysis was the code set preparation, focussing only on students with AS. Analysed data were linked qualitatively and deductively to ICF together with information from five different sources: 1) Student narratives, 2) International diagnosis classifications, 3) National policy-documents of higher education, 4) National healthcare and 5) The Swedish Autism and Asperger Syndrome Association. In all, 10 documents were included on the basis of  the AS target group, age group young adults, education and education guidelines for higher education, remedial work, need of support as well as national and international sources relating to the target group. The aim was to integrate several perspectives of needs of support in reference to AS students and their everyday student-life on a university campus. Results of the second study showed that even though other groups also reported problems similar to those of the AS students their explanations varied. While the problems of AS students appeared linked to cognitive difficulties, the problems of mobility impaired students (MD) and hearing impaired students (HD) were linked to physical difficulties. The difficulties and each group would appear similar at first sight which in practical terms means that they also would be offered the same kind of support as students at university The analysis of the questionnaire suggested the importance of students acquiring a job after graduation, to be able to earn a living and lead a normal everyday student-life like most others. However, prior to such a possible future studies must be completed and participants’ experiences of being university students appeared not the best. They spoke of struggle and alienation. Some of the experiences common to all three groups were stress and concentration difficulties, fatigue and social limitations. Hence, the second study, just like the first study, clearly showed both problems and needs, which suggested the necessity of a knowledge and communication tool for coordinators and students. An ICF-based code set for students with AS in higher education could serve as such a tool. In conclusion, results also suggested that if students with AS are to be included in higher education, and exclusion mechanisms such as stigmatisation and alienation be overcome, then clearly structured solutions - individual to each student - are also needed. Offered support must conform to multifinality rather than to equifinality as is currently the case in Sweden. Individual support cannot be based entirely on a diagnosis but also on an analysis of each student’s experienced difficulties in their immediate university environment of studying. Then, possibly, the available and legally guaranteed support would become as empowering as it was intended to actually be.
APA, Harvard, Vancouver, ISO, and other styles
24

Neves, Evelina Maria de Almeida. "Estratégia atencional para busca visual e reconhecimento invariante de objetos baseada na integração de características bottom-up e top-down." Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-14032014-103419/.

Full text
Abstract:
Uma das tarefas básicas dos mecanismos atencionais é decidir qual a localização dentro do campo visual, em que devemos prestar atenção primeiro. Um objeto que contenha características distintas, tais como orientação, forma, cor, tamanho, brilho, textura, etc. diferentes, pode atrair a atenção de uma maneira \"bottom-up\". A informação \"top-down\" baseia-se no conhecimento prévio e tem uma grande influência nas localizações atendidas. Inspirado nos mecanismos da Atenção Visual Humana, embora sem a pretensão de simulá-la, este trabalho prevê o desenvolvimento de uma nova metodologia que integra os dois tipos de informações: \"bottom-up\" e \"top-down\". Características \"bottom-up\" são geradas a partir de Momentos e essas informações são utilizadas em mapas de saliência, enquanto que um conhecimento prévio é utilizado para gerar pistas \"top-down\". Neste trabalho, desenvolveu-se uma metodologia específica para a busca e o reconhecimento visual em cenas com múltiplos objetos, utilizando para isso uma rede \"fuzzy\" contendo três subsistemas \"fuzzy\". Dada uma imagem de entrada, o objetivo consiste em se detectar regiões que possam conter informações mais significativas, a fim de que se possa guiar e restringir processamentos mais complexos. A inclusão de mecanismos de atenção (seleção de uma região de interesse dentro da imagem) é de fundamental importância pois os resultados obtidos pelo método podem ser usados para controlar a aquisição da imagem de uma maneira dinâmica. O modelo proposto está estruturado em três estágios principais: O primeiro estágio consiste em se segmentar os objetos e extrair características globais dos mesmos baseadas principalmente na teoria dos momentos, tais como tamanho, orientação, formato e distância e também média de nível de cinza. Por intermédio da comparação de um objeto com os outros presentes na cena, características \"bottom-up\" de conspicuidade são usadas para guiar a atenção ao objeto mais diferente. Por intermédio do uso da lógica \"fuzzy\" é possível inferir com grande flexibilidade algumas regras de decisão baseadas nos princípios de percepção visual tais como as leis Gestalt. O segundo estágio consiste de um subsistema \"fuzzy top-down\" que combina diferentes características de acordo com a relevância das mesmas em diferentes tarefas. Finalmente, o terceiro estágio consiste de um subsistema \"fuzzy\" que integra as informações obtidas dos subsistemas anteriores e fornece um índice geral de saliência, e indica a provável localização do objeto a ser reconhecido. A nova abordagem foi testada com objetos geométricos levando-se em consideração as características que atraem a atenção dos serem humanos
One of the basic tasks assigned to the human attentional mechanisms is to decide which location in the visual field we must pay attention first. An object containing distinctive features (such as different orientation, shape, color, size, shine, texture, etc.) can attract attention in a bottom-up way. Top-down information is based on the previous knowledge and has a large influence on the attended locations. Inspired on human visual attention mechanisms, although it doesn\'t want simulate it, this work presents a new methodology to integrate two different kind of information: bottom-up and top-down. Bottom-up features are obtained from Moment Theory and this information is used in salience maps, while a previous knowledge is used to create top-down hints. In this work, an specific methodology to visual search and recognition was developed to be applied to scenes containing multiple objects by a fuzzy net with three fuzzy subsystems. The aim of this methodology is to detect regions that may contain the most significant information, in order to guide and to restrict most complex processing. The inclusion of attentional mechanisms (the selection of a region of interest in the image) is fundamental and can be used to control the image acquisition in a dynamic way. The proposed model is structured in three main stages. The first stage segments the objects and extracts global features of them, based on the Moment Theory such as size, orientation, shape and distance and gray level average. By comparing one object with the other ones present in the scene, bottom-up features of conspicuity are used to guide the attention to the most different object. The Fuzzy Logic allows us to infer with great flexibility some of decision rules based on the visual perception principles such as the Gestalt Laws. The second stage is a top-down fuzzy subsystem that combines different features according to the relevance of them in different tasks. Finally, the third stage is a fuzzy subsystem that integrates the information obtained from the previous sub-systems and gives us a general salience index. The new methodology was tested in geometrical objects considering the feature that attracts attention to human beings
APA, Harvard, Vancouver, ISO, and other styles
25

Payette, Jordan. "Les actions de groupes en géométrie symplectique et l'application moment." Thèse, 2014. http://hdl.handle.net/1866/11640.

Full text
Abstract:
Ce mémoire porte sur quelques notions appropriées d'actions de groupe sur les variétés symplectiques, à savoir en ordre décroissant de généralité : les actions symplectiques, les actions faiblement hamiltoniennes et les actions hamiltoniennes. Une connaissance des actions de groupes et de la géométrie symplectique étant prérequise, deux chapitres sont consacrés à des présentations élémentaires de ces sujets. Le cas des actions hamiltoniennes est étudié en détail au quatrième chapitre : l'importante application moment y est définie et plusieurs résultats concernant les orbites de la représentation coadjointe, tels que les théorèmes de Kirillov et de Kostant-Souriau, y sont démontrés. Le dernier chapitre se concentre sur les actions hamiltoniennes des tores, l'objectif étant de démontrer le théorème de convexité d'Atiyha-Guillemin-Sternberg. Une discussion d'un théorème de classification de Delzant-Laudenbach est aussi donnée. La présentation se voulant une introduction assez exhaustive à la théorie des actions hamiltoniennes, presque tous les résultats énoncés sont accompagnés de preuves complètes. Divers exemples sont étudiés afin d'aider à bien comprendre les aspects plus subtils qui sont considérés. Plusieurs sujets connexes sont abordés, dont la préquantification géométrique et la réduction de Marsden-Weinstein.
This Master thesis is concerned with some natural notions of group actions on symplectic manifolds, which are in decreasing order of generality : symplectic actions, weakly hamiltonian actions and hamiltonian actions. A knowledge of group actions and of symplectic geometry is a prerequisite ; two chapters are devoted to a coverage of the basics of these subjects. The case of hamiltonian actions is studied in detail in the fourth chapter : the important moment map is introduced and several results on the orbits of the coadjoint representation are proved, such as Kirillov's and Kostant-Souriau's theorems. The last chapter concentrates on hamiltonian actions by tori, the main result being a proof of Atiyah-Guillemin-Sternberg's convexity theorem. A classification theorem by Delzant and Laudenbach is also discussed. The presentation is intended to be a rather exhaustive introduction to the theory of hamiltonian actions, with complete proofs to almost all the results. Many examples help for a better understanding of the most tricky concepts. Several connected topics are mentioned, for instance geometric prequantization and Marsden-Weinstein reduction.
APA, Harvard, Vancouver, ISO, and other styles
26

Raffoul, Raed Wissam Mathematics &amp Statistics Faculty of Science UNSW. "Functional calculus and coadjoint orbits." 2007. http://handle.unsw.edu.au/1959.4/43693.

Full text
Abstract:
Let G be a compact Lie group and let π be an irreducible representation of G of highest weight λ. We study the operator-valued Fourier transform of the product of the j-function and the pull-back of ?? by the exponential mapping. We show that the set of extremal points of the convex hull of the support of this distribution is the coadjoint orbit through ?? + ??. The singular support is furthermore the union of the coadjoint orbits through ?? + w??, as w runs through the Weyl group. Our methods involve the Weyl functional calculus for noncommuting operators, the Nelson algebra of operants and the geometry of the moment set for a Lie group representation. In particular, we re-obtain the Kirillov-Duflo correspondence for compact Lie groups, independently of character formulae. We also develop a "noncommutative" version of the Kirillov character formula, valid for noncentral trigonometric polynomials. This generalises work of Cazzaniga, 1992.
APA, Harvard, Vancouver, ISO, and other styles
27

Ascah-Coallier, Isabelle. "Cohomologie de fibrés en droite sur le fibré cotangent de variétés grassmanniennes généralisées." Thèse, 2013. http://hdl.handle.net/1866/9701.

Full text
Abstract:
Cette thèse s'intéresse à la cohomologie de fibrés en droite sur le fibré cotangent de variétés projectives. Plus précisément, pour $G$ un groupe algébrique simple, connexe et simplement connexe, $P$ un sous-groupe maximal de $G$ et $\omega$ un générateur dominant du groupe de caractères de $P$, on cherche à comprendre les groupes de cohomologie $H^i(T^*(G/P),\mathcal{L})$ où $\mathcal{L}$ est le faisceau des sections d'un fibré en droite sur $T^*(G/P)$. Sous certaines conditions, nous allons montrer qu'il existe un isomorphisme, à graduation près, entre $H^i(T^*(G/P),\mathcal{L})$ et $H^i(T^*(G/P),\mathcal{L}^{\vee})$ Après avoir travaillé dans un contexte théorique, nous nous intéresserons à certains sous-groupes paraboliques en lien avec les orbites nilpotentes. Dans ce cas, l'algèbre de Lie du radical unipotent de $P$, que nous noterons $\nLie$, a une structure d'espace vectoriel préhomogène. Nous pourrons alors déterminer quels cas vérifient les hypothèses nécessaires à la preuve de l'isomorphisme en montrant l'existence d'un $P$-covariant $f$ dans $\comp[\nLie]$ et en étudiant ses propriétés. Nous nous intéresserons ensuite aux singularités de la variété affine $V(f)$. Nous serons en mesure de montrer que sa normalisation est à singularités rationnelles.
In this thesis, we study the cohomology of line bundles on cotangent bundle of projective varieties. To be more precise, let $G$ be an semisimple algebraic group which is simply connected, $P$ a maximal subgroup and $\omega$ a dominant weight that generates the character group of $P$. Our goal is to understand the cohomology groups $H^i(T^*(G/P),\mathcal{L})$ where $\mathcal{L}$ is the sheaf of sections of a line bundle on $T^*(G/P)$. Under some conditions, we will show that there exists an isomorphism, up to grading, between $H^i(T^*(G/P),\mathcal{L})$ and $H^i(T^*(G/P),\mathcal{L}^{\vee})$. After we worked in a theoretical setting, we will focus on maximal parabolic subgroups related to nilpotent varieties. In this case, the Lie algebra of the unipotent radical of $P$ has a structure of prehomogeneous vector spaces. We will be able to determine which cases verify the hypothesis of the isomorphism by showing the existence of a $P$-covariant $f$ in $\comp[\nLie]$ and by studying its properties. We will be interested by the singularities of the affine variety $V(f)$. We will show that the normalisation of $V(f)$ has rational singularities.
APA, Harvard, Vancouver, ISO, and other styles
28

Callies, Martin. "Permuting actions, moment maps and the generalized Seiberg-Witten equations." Doctoral thesis, 2016. http://hdl.handle.net/11858/00-1735-0000-0028-8738-7.

Full text
APA, Harvard, Vancouver, ISO, and other styles
29

Smith, Kathleen. "Connectivity and Convexity Properties of the Momentum Map for Group Actions on Hilbert Manifolds." Thesis, 2013. http://hdl.handle.net/1807/43721.

Full text
Abstract:
In the early 1980s a landmark result was obtained by Atiyah and independently Guillemin and Sternberg: the image of the momentum map for a torus action on a compact symplectic manifold is a convex polyhedron. Atiyah's proof makes use of the fact that level sets of the momentum map are connected. These proofs work in the setting of finite-dimensional compact symplectic manifolds. One can ask how these results generalize. A well-known example of an infinite-dimensional symplectic manifold with a finite-dimensional torus action is the based loop group. Atiyah and Pressley proved convexity for this example, but not connectedness of level sets. A proof of connectedness of level sets for the based loop group was provided by Harada, Holm, Jeffrey and Mare in 2006. In this thesis we study Hilbert manifolds equipped with a strong symplectic structure and a finite-dimensional group action preserving the strong symplectic structure. We prove connectedness of regular generic level sets of the momentum map. We use this to prove convexity of the image of the momentum map.
APA, Harvard, Vancouver, ISO, and other styles
30

Chun-chu, Lee, and 李君祝. "The vocabulary learning in german-as- a foreign language textbooks "Themen neu", "Stufen international", "Moment mal"," Passwort Deutsch"." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/11491351649808064909.

Full text
Abstract:
碩士
輔仁大學
德國語文學系
93
Abstract: Each teaching method plans different processes of vocabulary learning .Nowadays, vocabulary learning will be connected with methods of intercultural-kommunicative aspect, right and left hemisphere aspect, cognitive aspect, intentional und unintentional aspect und motive aspect. In class, planning of vocabulary learning is not only connected with those methods, but also at first four important questions must be considered seriously: (1)what are the best words to learn first and how many words should be learned in a foreign language?(2)What are the best means of learning and retaining new words?(3)How to make sure of the examination of vocabulary acquisition and learning?(4)How to let a learner to use words he has learned? how to translate received words into productive words? To answer these questions, vocabulary leaning have to not only use systematically those methods to class, but also pay much attention to learn goals and learners. Vocabulary learning is put much concern on learning goals and learners, which influence choice of subjects (themes), arrangement of quantity of words and vocabulary practices in textbooks. My thesis will try to analyze” vocabulary learning in the German-as-foreign language textbooks ” and research subject(theme), quantity of words, word practice and progression.
APA, Harvard, Vancouver, ISO, and other styles
31

Κουλούκας, Θεόδωρος. "Δράσεις ομάδων Lie σε πολλαπλότητες Poison." Thesis, 2006. http://nemertes.lis.upatras.gr/jspui/handle/10889/893.

Full text
APA, Harvard, Vancouver, ISO, and other styles
32

"I saw lobato through emília: illustrated emílias for lobatos three moments." Tese, MAXWELL, 2005. http://www.maxwell.lambda.ele.puc-rio.br/cgi-bin/db2www/PRG_0991.D2W/SHOW?Cont=7290:pt&Mat=&Sys=&Nr=&Fun=&CdLinPrg=pt.

Full text
APA, Harvard, Vancouver, ISO, and other styles
33

Turesson, Sofia, and Malin Almén. ""Det är inte så att man typ har ångest inför lektionen eller nåt sånt där" : En kvalitativ studie kring hur olika moment i idrott och hälsa upplevs av elever." Thesis, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:gih:diva-3625.

Full text
Abstract:
Syfte: Syftet med undersökningen är att granska olustmoment inom ämnet idrott och hälsa.Studiens frågeställningar är: Vilka moment inom idrott och hälsa uppfattar eleverna i denna studie som olustiga? På vilket sätt upplevs momenten som olustiga? Metod: En kvalitativ undersökning med halvstrukturerade intervjuer utfördes på åtta elevermellan 9 och 18 år, på en grundskola och ett gymnasium i samma geografiska område inärheten av Stockholm. De deltagande eleverna var en flicka och en pojke i årskurs tre, sexoch nio samt andra året på gymnasiet. Resultat: Aktiviteter kan ge upphov till situationer som kan uppfattas som olustiga.Exempelvis kan fotboll leda till inaktivitet och därmed känslor av utanförskap, samtidigt somsamarbetsövningar med fysisk närkontakt kan leda till ångest. Vikten av att vara duktig på enaktivitet för att det ska kännas roligt diskuterades av många elever, speciellt itävlingssammanhang. Stress över betyg samt en alltför seriös stämning ansågs även det ledatill olustkänslor. Det uttrycktes ett starkt missnöje över ofräscha duschar och toaletterna pågrundskolan. Några elever fann det olustigt att duscha av olika anledningar. Studien pekar påvissa skilda åsikter såväl mellan åldrar som mellan kön, dock inget generaliserbart. Slutsatser: Vi tror att en förutsättning för att kunna undvika olustkänslor är att identifieradem och dess ursprung. Om de elever som idag känner sig inaktiva inkluderas mer i olikaaktiviteter kanske det leder till att andra känslor och upplevelser kopplas till dessa. Ifalleleverna ges förutsättningar till att hantera situationen bättre än vad de idag upplever att degör, skulle känslan av sammanhang förhoppningsvis öka, och därmed även elevernas lust ochvilja till att delta. Ett stort ansvar ligger självfallet på lärarna, som ska lyckas inspirera,inkludera och aktivera.
Aim: The purpose of this study is to survey unpleasant moments in physical education. Thequestion formulations of the study are: Which moments in physical education are perceived as unpleasant by the pupils in thisstudy? In which way do these moments perceive as unpleasant? Method: A qualitative study with semi-structured interviews was conducted with eight pupilsbetween 9 and 18 years old, at a school consisting of both elementary school and junior high,and also at a high school located in the same geographical area near Stockholm. Theparticipating pupils were a girl and a boy in third, sixth and ninth grade as well as junior yearof high school. Results: Activities can create situations that may be perceived as unpleasant. For example,soccer can lead to inactivity and thus feelings of alienation, while cooperation exercises withclose physical contact can lead to anxiety. The importance of being good at an activity inorder to make it fun was discussed by many pupils, especially in a competitive context.Pressure from grades as well as an overly serious atmosphere was also considered to causeunpleasant feelings. The pupils expressed strong dissatisfaction with the showers and toiletsin elementary school and junior high. Some pupils felt uncomfortable to shower for differentreasons. This study shows some differences of opinion both in between ages and gender,although, however, nothing generalizable. Conclusions: We believe that a prerequisite to avoid unpleasant feelings is to identify themand their origin. If the pupils that feel inactive would become more included in variousactivities, it might lead to other feelings and experiences associated with them. If the pupilsare given the opportunities to handle the situation better than what they currently feel likethey are doing, the sense of coherence hopefully increase, and thus the students' desire andwillingness to participate. The teachers need to take a major responsibility, since their task isto inspire, include and activate.
APA, Harvard, Vancouver, ISO, and other styles
34

Rakotoarison, Harijaona Lalao. "Méthode et outil de génération automatique de modèle pour l'optimisation fortement contrainte des microsystèmes magnétiques." Phd thesis, 2007. http://tel.archives-ouvertes.fr/tel-00200868.

Full text
Abstract:
Les MEMS magnétiques présentent encore des champs de recherches quasi inexplorées. La course à la recherche de faisabilité d'une nouvelle structure (actionneur, capteur) est un enjeu pour les concepteurs dans ce domaine.
Pour répondre à ce besoin, ce travail expose des méthodes et des outils permettant de faciliter et d'automatiser des taches répétitives qui sont à la charge de ces concepteurs. Le processus de génération automatique des équations représentant le modèle est maintenant délégué à l'outil que nous avons développé. La dérivation formelle des modèles est aussi étudiée et réalisée, notamment dans le cas des applications contenant des matériaux non linéaires (ferromagnétiques). A partir de ces travaux, il alors possible de dimensionner rapidement les MEMS magnétiques généralement soumis à de nombreuses contraintes non linéaires. La méthodologie peut être aussi étendu aux MEMS électrostatiques.
APA, Harvard, Vancouver, ISO, and other styles
35

Pondi, Endengle Eric Marius. "Essays in empirical asset pricing." Thèse, 2018. http://hdl.handle.net/1866/21778.

Full text
APA, Harvard, Vancouver, ISO, and other styles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography