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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Illusions thermiques basées sur les métamatériaux et les métasurfaces : conduction et rayonnement / Thermal illusions based on metamaterials and metasurfaces : heat conduction and thermal radiation

Alwakil, Ahmed Diaaeldin 27 June 2018 (has links)
Les techniques de camouflage, mimétisme ou invisibilité ont récemment connu une forte émergence, qui se poursuit aujourd’hui avec l’apparition des méta-surfaces. C’est dans ce contexte que ce travail de doctorat a été réalisé, notamment avec un premier objectif d’étendre ces outils et concepts aux problèmes inverses du domaine de la diffusion de la chaleur. La suite du travail a concerné le rayonnement thermique, les méta-surfaces et les transformations de champ. Après avoir étendu les techniques de mimétisme au domaine de la conduction, nous avons résolu le problème inverse associé, qui consiste à camoufler des objets imposés en forme ou conductivité. Ce premier travail a permis de mettre en évidence les classes de transformation qui laissent invariantes les paramètres physiques, conférant ainsi plus de pragmatisme au domaine du mimétisme. Nous avons ensuite considéré le cas du rayonnement thermique, et démontré pour la première fois que les illusions par rayonnement étaient envisageables, en appui sur l’invariance du théorème de fluctuation/dissipation. Dans une deuxième étape, nous avons mis au point une nouvelle méthode pour calculer le rayonnement thermique par des objets de forme arbitraire, mettant en jeu des méta-surfaces inhomogènes, anisotropes, chirales et non locales. Nous montrons également comment tirer profit des méta-surfaces pour remplacer les capes volumiques tout en conservant la fonction de camouflage. Cette technique est particulièrement prometteuse pour les applications, même si elle reste intrinsèquement liée à l’éclairement. Des techniques similaires sont développées pour que soit facilité l’utilisation de transformations discontinues de l’espace. / Mimetism, camouflage or invisibility have motivated numerous efforts in the last decade, which are now extended with metasurfaces. This PhD work fits this international context and was first focused on inverse problems in heat conduction before we address thermal radiation and metasurfaces, field transformation. After we generalize the mimetism techniques to heat diffusion, we solved the associated inverse problem which consists of the camouflage of given objects, that is, objects with shape or conductivity that are before hand chosen. The results allowed us to emphasize the class of transformations which hold the physical parameters, hence giving more pragmatism to the field of mimetism. Then we addressed the case of thermal radiation and proved for the first time that mimetism effects could also be controlled in this field, on the basis of the fluctuation/dissipation theorem. In a second step, we built an original technique able to predict the thermal radiation from objects of arbitrary shapes. This technique involves inhomogeneous, anisotropic, chiral and nonlocal metasurfaces. We also show how to take more benefits of metasurfaces in order to replace the bulk mimetism cloaks. We believe this technique to give again more push forward to the field, though the mimetism efficiency now relies on the illumination conditions. Similar techniques are further developed to allow a practical use of discontinuous space transformations. Eventually, field transformation is introduced to complete all these results.
122

Módulos neurais para modelagem de falsas memórias / Neural modules for false memories modelling

Pacheco, Renato Ferrari 08 April 2004 (has links)
As falsas memórias são um tipo falha de memória, em que o indivíduo pode (a) reconhecer como tendo visto antes um objeto ou evento que não tenha ocorrido ou (b) não reconhecer algo previamente presenciado. Estes são o falso reconhecimento e a rejeição errada. Segundo a teoria do rastro difuso, dois processos distintos agem em paralelo durante a memorização e reconhecimento, um sobre as informações literais (verbatim) e o outro sobre a essência do significado da palavra (gist). Neste trabalho é proposto um sistema modular de redes neurais artificiais que considera estes dois processos, características funcionais das estruturas cerebrais envolvidas na memorização e fluxo de informação análogo ao ocorrido no cérebro. O modelo neural é validado através de treinamento para armazenar e recuperar listas de palavras semanticamente relacionadas. Na formulação do modelo e da representação foram considerados a representação fonológica e significado das palavras, de forma a simular as computações ocorridas e os resultados obtidos em experimentos efetuados com sujeitos humanos. Nestes experimentos, 12 listas de aproximadamente 15 palavras, cada lista semanticamente relacionadas a um tema são ouvidas e, em seguida, algumas destas palavras, a palavra tema e outras palavras não relacionadas são também ouvidas e os indivíduos respondem se cada palavra fora ouvida previamente. Os resultados obtidos computacionalmente aproximam-se bastante dos resultados obtidos com sujeitos humanos, e o modelo produzido serve como base para estudo das influências dos diversos processos atuantes durante a memorização e reconhecimento. / False memories are a kind of memory failure, in which the subject may (a) recognize as known an never seen object or never happened fact or (b) don\'t recognize something that was already presented him. These are false memories and wrong rejections. According to false memory theory, two parallel processes act during memorization and recognition, one on verbatim information and other on gist information. In this work is proposed a artificial neural network model system that takes in account these two processes, functional issues about brain structures involved on memorization and the an information flow analog to the occurred in the brain. The neural model is validated by training to store in recover lists of semantically related words. In the model and representation scheme formulation, phonological and semantic informations were used intending to simulate brain computations and results of human subjects experiments. In such experiment, 12 lists of something about 15 semantically related words, are heard and, in the second step, in the sequence, many of these words, other related words and not related words are heard in a recognition test, when subjets say if that word was or was not heard during memorization steps. Results obtained from computer tests are very close of human results, and the produced model may be used as a tool for analysis of the influences of the many processes that take place during memorization and recognition.
123

Perception of visual motion speed in human und monkey / Die Wahrnehmung der visuellen Geschwindigkeit bei Mensch und Affe

Boyraz, Pinar 19 April 2007 (has links)
No description available.
124

Módulos neurais para modelagem de falsas memórias / Neural modules for false memories modelling

Renato Ferrari Pacheco 08 April 2004 (has links)
As falsas memórias são um tipo falha de memória, em que o indivíduo pode (a) reconhecer como tendo visto antes um objeto ou evento que não tenha ocorrido ou (b) não reconhecer algo previamente presenciado. Estes são o falso reconhecimento e a rejeição errada. Segundo a teoria do rastro difuso, dois processos distintos agem em paralelo durante a memorização e reconhecimento, um sobre as informações literais (verbatim) e o outro sobre a essência do significado da palavra (gist). Neste trabalho é proposto um sistema modular de redes neurais artificiais que considera estes dois processos, características funcionais das estruturas cerebrais envolvidas na memorização e fluxo de informação análogo ao ocorrido no cérebro. O modelo neural é validado através de treinamento para armazenar e recuperar listas de palavras semanticamente relacionadas. Na formulação do modelo e da representação foram considerados a representação fonológica e significado das palavras, de forma a simular as computações ocorridas e os resultados obtidos em experimentos efetuados com sujeitos humanos. Nestes experimentos, 12 listas de aproximadamente 15 palavras, cada lista semanticamente relacionadas a um tema são ouvidas e, em seguida, algumas destas palavras, a palavra tema e outras palavras não relacionadas são também ouvidas e os indivíduos respondem se cada palavra fora ouvida previamente. Os resultados obtidos computacionalmente aproximam-se bastante dos resultados obtidos com sujeitos humanos, e o modelo produzido serve como base para estudo das influências dos diversos processos atuantes durante a memorização e reconhecimento. / False memories are a kind of memory failure, in which the subject may (a) recognize as known an never seen object or never happened fact or (b) don\'t recognize something that was already presented him. These are false memories and wrong rejections. According to false memory theory, two parallel processes act during memorization and recognition, one on verbatim information and other on gist information. In this work is proposed a artificial neural network model system that takes in account these two processes, functional issues about brain structures involved on memorization and the an information flow analog to the occurred in the brain. The neural model is validated by training to store in recover lists of semantically related words. In the model and representation scheme formulation, phonological and semantic informations were used intending to simulate brain computations and results of human subjects experiments. In such experiment, 12 lists of something about 15 semantically related words, are heard and, in the second step, in the sequence, many of these words, other related words and not related words are heard in a recognition test, when subjets say if that word was or was not heard during memorization steps. Results obtained from computer tests are very close of human results, and the produced model may be used as a tool for analysis of the influences of the many processes that take place during memorization and recognition.
125

Rodina v moderním americkém dramatu / Family in modern American drama

Hovorka, Jan January 2011 (has links)
This work analyses the American family in context of society and its demands. It focuses on the cannonical works of the Modern American drama, namely plays of Tennessee Williams, Arthur Miller, Edward Albee, Sam Shepard and David Mamet. The playwrights are analysed in two distinctive groups according to similar themes they share. Tennessee Williams and Arthur Miller depict the family under increasing pressure from the outside as well from the inside. The unit disintegrates, members of the family escape and thus the unit loses its funtions. The pressure is imposed by the tenets of the American mythology that governs the society, which, in turn, influences the family. The common theme of the first group of playwrights is the feeling of loss. This comprises of two dimensions - spatial and tempoval. The second group of playwrights share the same theme of loss with its spatial and temporal implications. They are characteristic by their distinctive use of language that depicts the prevalent sense of doom, apocalypse, futility and sterility. The search for identity is also implied by the restlessness of characters. The detrimental effect of harsh business environment on the family is explored with regards to masculinity. The work shows the family in the context of the 1950s, an era when the family was elevated to...
126

Unterstellungen

Hildebrandt, Frauke 12 February 2007 (has links)
Der Unterstellungsbegriff ist ein zentraler Begriff innerhalb transzendentaler Argumente. Transzendentale Argumente sind Versuche, empirische Erkenntnis stabiler zu sichern als durch empirische Erkenntnis selbst. Dabei müssten, heißt es immer wieder, bestimmte grundlegende Sachverhalte unterstellt werden. Was genau bedeutet hier „unterstellen“? Exemplarisch wird in dieser Arbeit Habermas’ Verwendung des Unterstellungsbegriffs und des eng verwandten Voraussetzungsbegriffs nachvollzogen und interpretiertHabermas verwendet seinen Kernbegriff nicht einheitlich, insbesondere unterscheidet er nicht zwischen semantischem und epistemischem Voraussetzungsbegriff. Im Gegensatz zum semantischen Voraussetzungsbegriff, der eine Relation zwischen Sachverhalten beschreibt, kennzeichnet der epistemische Voraussetzungsbegriff eine Relation zwischen einem epistemischen Subjekt und einem Sachverhalt. Mit der Verwendung des Ausdrucks Unterstellung konstruiert Habermas einen internen, konstitutiven Zusammenhang zwischen unserer Kommunikationsfähigkeit und grundlegend verschiedenen propositionalen, epistemischen Einstellungen, ohne dass diese terminologisch voneinander abgegrenzt werden. Handelt es sich um Fiktionen, Hypothesen oder um handfeste Überzeugungen? Der rekonstruierte Zusammenhang erweist sich in Abhängigkeit von der durch das Verb unterstellen jeweils ausgedrückten propositionalen Einstellung – doxastisch-affirmativ, doxastisch-negierende oder nicht-doxastisch - entweder als unverständlich oder als trivial. Die als notwendige Voraussetzungen benannten Unterstellungen haben aufgrund der Semantik des Ausdrucks unterstellen hinsichtlich ihres epistemischen Status’ also keinen klaren Sinn. Damit scheitert a fortiori auch Habermas’ Versuch, notwendige Unterstellungen als schwach transzendentale Grundlage kommunikativen Handelns zu bestimmen. Die Inakzeptanz transzendentaler Argumente – auch in ihrer nicht-metaphysischen, von Habermas favorisierten „schwachen“ Lesart – wird durch die Formulierung „unterstellen müssen“ als Bestandteil des Schlussprinzips oder einer Prämisse transzendentaler Argumente systematisch verschleiert. / The concept of presuppositions is central for transcendental arguments. Transcendental arguments are efforts to validate empirical knowledge more effectively than through empirical knowledge itself. According to widely held views some fundamental propositions have to be presupposed for that purpose. But what – precisely – does “to presuppose something” mean? This paper will exemplarily reconstruct and interpret the use of the concept of presupposition in Jürgen Habermas’ work: Habermas doesn’t use this central concept in a homogeneous, standardized way: In particular he does not distinguish between the semantic and the epistemological concept. In contrast to the semantic concept, which describes a relationship between propositions, the epistemological concept characterizes a relationship between an epistemological subject and a proposition. Moreover, using the term “presupposition”, Habermas constructs an internal, constitutive connection between our ability to communicate and fundamentally different propositional, epistemological attitudes, without distinguishing them from each other. Is it a matter of fictions, hypotheses or beliefs? The reconstructed connection appears to be either incomprehensible or trivial given its dependence on the verb “to presuppose”, which can imply the propositional attitude of doxastic-affirmative, doxastic-negating or non-doxastic. The presuppositions claimed to be essential are not clearly defined in terms of their epistemological status because of the semantics of the term to presuppose. Therefore, Habermas’ attempt to determine essential presuppositions as a transcendental basis for communication also fails a fortiori. The non-acceptance of transcendental arguments – even in their non-metaphysic interpretation favoured by Habermas – is disguised as constituent of the premise of the corpus by the phrase “to have to presuppose”.
127

Paul Auster's representation of invisible characters in selected novels

Gous, Joané Facqueline January 2012 (has links)
In this dissertation I argue that invisible characters, as they appear in Paul Auster’s novels, serve a very specific function within the interpretative framework of a text and that they should be considered to play a functional role, in order to arrive at a more holistic interpretation of the text and a more accurate analysis of said texts. I argue that Auster knowingly includes these characters in his novels as part of his narrative technique, in order for them to serve specific functions and to contribute to the structure of postmodern fiction. I make use of a contextualized close reading of five of Auster’s novels and attempt a hermeneutic interpretation of these novels to arrive at a hermeneutic circle when combining these novels into an integrated whole, individual, work of fiction. Certain parallels can be drawn between Auster’s various novels and these parallels contribute to the various motifs and themes found throughout his work. The importance of space in Auster’s novels is also highlighted with emphasis on liminality which serves as an instigator for transgression to occur between different fictive worlds. / Thesis (MA (English))--North-West University, Potchefstroom Campus, 2013.
128

Paul Auster's representation of invisible characters in selected novels

Gous, Joané Facqueline January 2012 (has links)
In this dissertation I argue that invisible characters, as they appear in Paul Auster’s novels, serve a very specific function within the interpretative framework of a text and that they should be considered to play a functional role, in order to arrive at a more holistic interpretation of the text and a more accurate analysis of said texts. I argue that Auster knowingly includes these characters in his novels as part of his narrative technique, in order for them to serve specific functions and to contribute to the structure of postmodern fiction. I make use of a contextualized close reading of five of Auster’s novels and attempt a hermeneutic interpretation of these novels to arrive at a hermeneutic circle when combining these novels into an integrated whole, individual, work of fiction. Certain parallels can be drawn between Auster’s various novels and these parallels contribute to the various motifs and themes found throughout his work. The importance of space in Auster’s novels is also highlighted with emphasis on liminality which serves as an instigator for transgression to occur between different fictive worlds. / Thesis (MA (English))--North-West University, Potchefstroom Campus, 2013.
129

Les romans de l'écrivain-journaliste d'Illusions perdues à Bel-Ami : continuités et ruptures

Couture, Maude 23 April 2018 (has links)
Nombreux sont les romans du XIXe siècle qui ont pour thème principal le journalisme. Le présent mémoire se donne pour objectif de retracer l’évolution et les transformations du scénario romanesque de l’écrivain-journaliste à travers trois romans majeurs sur la presse soit Illusions perdues (1843) d’Honoré de Balzac, Charles Demailly (publié en 1860 sous le titre Les hommes de lettres) des frères Edmond et Jules de Goncourt ainsi que Bel-Ami (1885) de Guy de Maupassant. Pour ce faire, nous situerons d’abord Illusions perdues comme le modèle matriciel de ce scénario en ce sens que se cristallise dans ce roman l’ensemble des éléments clés propres à ce scénario et nous verrons par la suite en quoi les romans des Goncourt et surtout de Maupassant s’en rapprochent et s’en distancent. Nous avons choisi de convoquer ces œuvres, car elles représentent des repères incontournables dans une étendue temporelle d’un peu plus de quarante ans.

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