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Massouras, Maryam. "Artificial spin ice : from statistical physics to stochastic computing". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0143.
Pełny tekst źródłaSince their introduction in 2006, artificial spin ice systems have sparked an interest for their similarity with frustrated systems such as water ice or some pyrochlores. These networks of interacting nanomagnets can be observed using simple microscopy techniques and be tailored at will. In this work, we have studied customised geometries in order to observe the evolution of dipolar interactions and develop a device. First, we have studied the tuning of the dipolar interactions induced by rotation of the elements of the square geometry. For an as-grown system that the ground state evolution from antiferromagnetic to ferromagnetic orders observed is consistent with dipolar computations. Taking into account the long-range interactions in our Monte Carlo simulations, we have described the total dipolar energy along with the vertex populations of our system with all its tilted networks. This has led to a study of the thermodynamics of our system and a unique effective could be ascribed. Secondly, we have taken an interest into the possibility of tailoring these artificial spin systems for applications in random number generation. We have seen that these systems are a better fit exploiting domain wall propagation rather than reversals by coupling. We have then established that the main challenge to overcome in large connected structures is the trade-off between nucleation field from the outputs and depinning field of the upper part of the nanostructure. Indeed, it is necessary to ensure than the domain wall propagating in the structure is indeed the injected one and that no parasitic nucleation occurs which is overcome this issue. The domain wall propagation has been characterised in terms of propagation fields and types of reversals. We have shown that our optimised system exhibits reversal induced by the injected domain wall mainly in unidimensional fashion with clear stochastic behaviour. The characterisation of this behaviour has shown that a mean weight value describes the choices observed which do not exhibit any correlation. Our artificial spin system therefore behaves as a Galton board, the prime device for random number generation. This PhD work has shown the versatility of artificial spin systems as spin ice for understanding the influence of tuned interactions in their thermodynamics. This work has also demonstrated their versatility for an application with the characterisation of their stochastic behaviour through an optimisation of the geometry
Perrin, Yann. "Réseaux artificiels à frustration géométrique". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY054/document.
Pełny tekst źródłaSince a decade, a big interest has grown about geometrically frustrated nanomagnets arrays. They allow experimental realisation of theoretical spin models, that sometimes have no natural counterpart. In addition to their high flexibility, these networks provide a direct access to local spin configurations. The work presented in this manuscript aims to realise experimentally the so-called "square ice" model, using nanomagnets array. This highly frustrated model has already been theoretically studied. It is found to have a massively degenerated ground state, associated to a residual entropy at low temperature. In this thesis, we present two approaches that should achieve the square ice model.The first one consists to introduce additional magnets in the conventional square nanomagnets array. They can act through an effective coupling between the magnets of the initial network. The condition required is that additional magnets should behave passively against main magnets. We will show in a theoretical study that a reciprocal space analysis of the Hamiltonian fails to grasp the essential properties of the new model. By computing the energy of a number of random spins configurations, we will show that the square ice model can be achieved. A special attention will be paid to the influence of the range and the nature of magnets interactions. Using finite-difference micromagnetic simulations, we will determine the geometries adapted to an experimental realisation. We were able to make such networks using the microfabrication tools available in the laboratory. Our magnets are made of thin permalloy films. This allows the magnets to reach a superparamagnetic regime during a thermal annealing. We observed that additional magnets have the expected influence on square nanomagnets arrays. However, an experimental bias caused a high residual magnetisation in some networks. This effect has unfortunately hided the correlations expected in the square ice model. But this work shown an unexpected effect. Additional magnets appear to enhance thermal fluctuations in the networks.The second approach is to raise the magnets oriented in one of the two directions of the square lattice. For the study of this new system, a methodology similar to that described above will be used. Theoretically, the control of the elevation can explore three different spins models, including the square ice model. We made arrays for different elevations, estimated by micromagnetic calculations. For technical reasons, we worked with thick permalloy nanomagnets. Their thickness makes them insensitive to thermal fluctuations. Fluctuations are then introduced using a decreasing rotating magnetic field. Our simulations show that this particular dynamic stimulates emergence of ferromagnetic correlations. The field demagnetisation then reduce the elevations required for achieving the square ice model. We have experimentally observed that the elevation has an effect perfectly consistent with our previsions. Experimental structure factors show that we succeed to achieve the square ice model with nanomagnets. This approach allowed us to observe, for the first time, a Coulomb phase in the real space. This work opens interesting perspectives for studying the excitations of this phase. It has previously been shown that they are similar to classical magnetic monopoles
Brunel, Vivien. "Systèmes de spins quantiques unidimensionnels. Désordre et impuretés". Phd thesis, Université Paris Sud - Paris XI, 1999. http://tel.archives-ouvertes.fr/tel-00000893.
Pełny tekst źródłaFrançois, Olivier. "Systèmes de spins synchronisés : modèles de Hopfield stochastiques". Grenoble 1, 1992. http://www.theses.fr/1992GRE10020.
Pełny tekst źródłaChen, Linxiao. "Cartes planaires aléatoires couplées aux systèmes de spins". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS096/document.
Pełny tekst źródłaThe aim of this thesis is to improve our understanding of random planar maps decorated by statistical physics models. We examine three particular models using tools coming from analysis, combinatorics and probability. From a geometric perspective, we focus on the interface properties and the local limits of the decorated random maps. The first model defines a family of random quadrangulations of the disk decorated by an O(n)-loop model. After completing the proof of its phase diagram initiated in [BBG12c] (Chap. II), we look into the lengths and the nesting structure of the loops in the non-generic critical phase (Chap. III). We show that these statistics, described as a labeled tree, converge in distribution to an explicit multiplicative cascade when the perimeter of the disk tends to infinity. The second model (Chap. IV) consists of random planar maps decorated by the Fortuin-Kasteleyn percolation. We complete the proof of its local convergence sketched in [She16b] and establish a number of properties of the limit. The third model (Chap. V) is that of random triangulations of the disk decorated by the Ising model. It is closely related to the O(n)-decorated quadrangulation when n=1. We compute explicitly the partition function of the model with Dobrushin boundary conditions at its critical point, in a form ameneable to asymptotics. Using these asymptotics, we study the peeling process along the Ising interface in the limit where the perimeter of the disk tends to infinity.Key words. Random planar map, O(n) loop model, Fortuin-Kasteleyn percolation, Ising model, local limit, interface geometry
Chioar, Ioan-Augustin. "Glaces kagomé de spins artificiels : de la dégénérescence à courte-portée vers l'ordre dipolaire". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAY033/document.
Pełny tekst źródłaArtificial spin networks were initially proposed as toy-spin models destined for the investigation of magnetic frustration effects in two-dimensional spin lattices, a complementary approach to the study of the magnetic frustration encountered in spin ice pyrochlores. Generally fabricated via lithography techniques, these arrays of nano-scale magnetic islands can be designed at-will. Given the size and shape of the elements, their magnetization is almost uniform throughout their volume, thus making these islands act like classical Ising spins. Combined with the possibility of individually imaging the magnetic degrees of freedom in real space, these systems offer an almost infinite playground for the investigation of competing interactions in magnetostatic frameworks and potential for the experimental discovery of novel and exotic magnetic phases. However, unlike their condensed matter counterparts, first-generation artificial spin networks are insensitive to thermal fluctuations, requiring other driving mechanisms for accessing their complex low-energy manifolds. A field-protocol has been employed for driving such networks towards their ground-state configurations, although they only partially manage to accommodate pair-island interactions. More recently, thermally-active artificial spin networks have been introduced, surpassing the limits of demagnetized arrays in the quest for exotic low-energy spin textures.This thesis presents experimental and numerical studies performed on artificial kagome spin arrays, one of the most frustrated two-dimensional lattices. The kagome spin ice geometry has received most of the community's attention as it presents highly degenerate manifolds and unconventional spin textures. Within a dipolar long-range framework, it displays a low-temperature regime characterized by the coexistence of a crystalline phase, associated to the magnetic charge, and a disordered spin lattice. While demagnetizing such artificial kagome arrays cannot access this exotic state, thermally-active networks can locally retrieve such a phase, creating crystallites of antiferromagnetically-ordered magnetic charges. The first part of this work presents the experimental protocol employed to this purpose. A kinetic model is also proposed that successfully captures the observed experimental features and explains the efficiency of this approach.The second part of the current thesis presents a study of a novel artificial spin ice system, the artificial kagome Ising network. This network primarily differs from the kagome spin ice array by having its magnetic moments pointing along the vertical axis. A recent study of this system has concluded that, after demagnetization, these two artificial kagome networks display similar pairwise spin correlation development and their final frozen states can be well characterized by short-range interaction models. Through the use of demagnetization protocols, magnetic force microscopy and Monte Carlo simulations, it is demonstrated that long-range dipolar interactions between the magnetic elements cannot be neglected when describing the remanent states of demagnetized artificial kagome Ising networks. These results assess the limits of the reported universal behavior of artificial kagome lattices and enrich the spectrum of magnetic phases that could be achieved with such nanostructured systems. Indeed, Monte Carlo simulations indicate that this kagome Ising network presents a different low-energy behavior than kagome spin ice, the incipient stages of which have been accessed experimentally, but its dipolar ground-state configuration remains unknown. Nevertheless, by inspecting the low-temperature thermodynamic features of this array and through the use of a geometrical construction, a ground-state candidate is provided
Ponthieu, Raphaël. "Les fourmis et les machines : interfacer systèmes vivants et systèmes artificiels". Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC072/document.
Pełny tekst źródłaWithin the animal kingdom social insects fascinate humans. Especially ants, which are capable of adapting to various environments and taking advantage of their biotopes. Observing practices that we would have thought to be exclusive to humans – such as farming (of mushrooms) or breeding (of aphids) – spurs the will to understand by which mean ants operate. It turns out that ants achieve certain tasks in different ways than humans. For instance, to find the shortest path to a food source, or the best nest to migrate to; the colony can make a collective decision, decentralized and without the need of direct comparisons by individuals. My work has consisted of the elaboration and use of new methods to study ants. Two complementary objectives have been chosen to drive the work: implementation of a biohybrid system and assessing the means of and limits to controlling the behaviour of ants. The first objective consists of asking ourselves what will happen if we connected an ant colony with a computer For this I have designed apparatus that permit interaction between those two entities. It involved giving sight to the computer into what the colony was doing, then providing ways for the computer to act on the colony. To do so, I designed and tried out tools to monitor the activity of colonies as well as modular environments which ants can inhabit. I designed an embedded system that records and analyses activity of ant colonies on a micro-computer. I designed and 3D printed modules of various sizes that can be assembled together to form a structurally varied environment. For the computer to be able to act upon ant behaviour, I chose to endow it with the capability of modifying environmental conditions, at particular temperatures. Once the system was built, I conducted experiments to assess how local changes of temperature affect ant behaviour. This characterisation of behaviour under temperature changes sheds light on the relation of ants with their environment. This permitted the exploration of questions of control of behaviour of ants by a machine. The use of temperature having proved its capacity to modulate the local occupancy density, I then have been able to show that it was possible to confine an ant in a set location. Finally, I implemented a closed feedback loop system, in which the temperature used to confine the ant is dependent on the ant activity in real time. This last experiment shed light on the complexity of the dynamic relation between ants and their environments and opened new perspectives for future investigations. During this research, many tools were developed. Functional prototypes of moduary environments have demonstrated the relevance of using 3D printers for the study of ants. The various tools for monitoring, recording and processing video data provide new and innovative experimental possibilities and can be used for other studies, especially over long periods of time. Temperature control devices have as well been designed using rapid prototyping tools, making them accessible, scalable and reproducible in an open source approach
Loireau, Maud. "Espaces, ressources, usages : spatialisation des interactions dynamiques entre les systèmes sociaux et les systèmes écologiques au Sahel nigérien". Montpellier 3, 1998. http://www.theses.fr/1998MON30058.
Pełny tekst źródłaNagy, Zoltan. "Systèmes intégrables et algèbres de réflexion dynamiques". Cergy-Pontoise, 2005. http://biblioweb.u-cergy.fr/theses/05CERG0270.pdf.
Pełny tekst źródłaThis thesis is a contribution to the study of different dynamical quadratic algebras and their applications to integrable systems. Dynamical quadratic algebras are generalizations of the reflection algebra introduced by Cherednik to deal with integrable systems on the half-line, and more generally with integrable systems with open boundary conditions. We define two dynamical quadratic algebras : fully dynamical and semi-dynamical. The former is a simple generalization of the boundary elliptic quantum group, the latter is a new structure. We show in both cases how to build families of commuting Hamiltonians as quantum analogues of the trace of powers of the classical Lax-matrix. We also show, making use of the comodule structure which we elucidate, how to construct spin chain type Hamiltonians using the representations of these algebras as building blocks. These results are self-contained in the sense that they make no use of the vertex-IRF correspondence linking dynamical and non-dynamical algebras
Bocquet, Marc. "Chaînes de Spins, Fermions de Dirac, et Systèmes Désordonnés". Phd thesis, Ecole Polytechnique X, 2000. http://tel.archives-ouvertes.fr/tel-00001560.
Pełny tekst źródłaEl-Bouanani, Hicham. "Vorticité dans des systèmes de spins à symétrie continue". Phd thesis, Université du Sud Toulon Var, 2008. http://tel.archives-ouvertes.fr/tel-00381684.
Pełny tekst źródłaDans le Chapître 1, on rappelle quelques propriétés de l'interaction entre plus proches voisins, pour le rotateur, ou sa version simplifiée appelée modèle de Villain. On introduit aussi le modèle du champ moyen.
Le modèle de Kac, qui partage certains aspects de ces deux modèles, est étudié au Chapître 2. Par un procédé d'homogénéisation, on ramène essentiellement l'étude de la mesure de Gibbs en volume fini à celle de la fonctionnelle énergie libre $\cal F$, généralisant des techniques utilisées dans le modèle d'Ising.
Les propriétés de vorticité du modèle de Kac sont analysées dans le Chapître 3, où l'on détermine les extrema de $\cal F$, avec conditions limite. On met ainsi en évidence des configurations très similaires à celles des solutions des équations de Ginzburg-Landau.
Dans le Chapître 4 on passe au cas quantique, en introduisant la notion de "matrice de vorticité" à température inverse $\beta$, dont on calcule le "degré non-commutatif". Il apparaît ainsi, pour le modèle XY de spin 1/2, des configurations de vorticité analogues à celles rencontrées dans le cas classique.
El, Bouanani Hicham. "Vorticité dans des systèmes de spins à symétrie continue". Toulon, 2008. https://theses.hal.science/tel-00381684v2.
Pełny tekst źródłaThis thesis concerns spins systems with continuous symmetry on a 2-D lattice. For XY model we consider second order phase transitions [Berezinskii, Kosterlitz and Thouless], related with vorticity of Gibbs states or order parameters (minimizers of free energy). Vortices are analogues with interfaces in Ising model; but internal continuous symmetry smears out phase transitions, excluding in 2-D spontaneous alimentation and allowing for a delay of correlation functions, even at low temperature. For Heisenberg model with Kac potential, vortices are replaced by instantons
Dargis, Pierre. "Structures non-locales dans les systèmes intégrables, systèmes KdV supersymétriques et chaînes de spins". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0005/NQ39345.pdf.
Pełny tekst źródłaAubourg, Lucile. "Contrôle et transmission de l'information dans les systèmes de spins". Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCD003/document.
Pełny tekst źródłaAt an atomic level, the spin control is an essential aim in quantum physics. Unfortunately, the presence of noises disturbs this last. The goal is to find the conditions which we have to impose to the environment in order that the control is not disturbed by the noise. The study of a spin chain characterized by three couplings (Heisenberg, Ising-Z and Ising-X interactions) freely evolving is taken as reference. We observe that the Heisenberg interaction corresponds to an isotropic coupling. The Ising-Z one conserves the order into the chain whereas the Ising-X one is really disordered. We consider a more complex quantum system by adding some control and analyzing its adiabatic behavior. This last is composed by a system and an environment, for which the coupling is perturbative. Three adiabatic regimes have been highlighted. Some formulas allowing to obtain the wave function across the time have been established for these three regimes. However, in practice, quantum systems are not isolated. The interaction with their environment can lead to more complex behaviors, driving the control more difficult. We have studied spin systems, coupled or not, kicked by some ultrashort magnetic pulse trains. These trains cross a classical environment (stationary, drift, Markovian, microcanonical) modifying the strength and the delay of each pulse. The modification of the trains by the environment is one of the sources of the disorder into the spin system. This disorder is transmitted between the spins by the coupling. In this study we do not succeed in controlling the system when the trains are in the presence of the previous environments. To remedy this situation, we force the magnetic pulses to cross a chaotic environment. Before a time t, called horizon of coherence, the system coupled by an Heisenberg interaction and submitted to a chaotic environment remains coherent whereas after, the population and the coherence of one spin and of the average spin of the system tend to go near the microcanonical distribution. During this horizon, it is possible to realize some quantum control either by total control (control of the system at every instants) or by information transmission. This study allows us to determine an empirical formula of the horizon of coherence. Finally, we have tried to find a more formal approach for this horizon
Villar, Vincent. "Etude expérimentale des effets quantiques dans deux systèmes de spins : aimant moléculaire Fe8 et chaîne de spins quantiques". Université Joseph Fourier (Grenoble), 2001. http://www.theses.fr/2001GRE10255.
Pełny tekst źródłaLefevre, Alexandre. "États métastables dans les systèmes désordonnés : des verres de spins aux". Phd thesis, Université Paul Sabatier - Toulouse III, 2003. http://tel.archives-ouvertes.fr/tel-00003321.
Pełny tekst źródłaDans une première partie, les propriétés dynamiques essentielles des modèles de verres de spins en champ-moyen sont passées en revues. La notion d'état métastable est ensuite discutée, ainsi que le lien avec la perte d'ergodicité dans la phase vitreuse. Enfin, plusieurs méthodes numériques et analytiques permettant de calculer l'entropie configurationnelle sont exposées en détail.
La seconde partie traite des états métastables dans les milieux granulaires. Un algorithme de "tapping" y est introduit, permettant d'obtenir un modèle paradigmatique pour l'étude des systèmes granulaires vibrés, partiellement accessible analytiquement. Le scénario proposé par Edwards selon lequel dans l'état stationnaire tous les états métastables sont visités avec la même probabilité est testée sur plusieurs modèles. L'étude de modèles unidimensionnels permet de comprendre la validité de cette approche aux grandes densités, alors que l'étude de modèles sur des graphes aléatoires montre que la mesure d'Edwards permet de décrire de façon précise des phénomènes non triviaux comme des transitions de phase. Enfin, des tests permettant de vérifier expérimentalement cette approche sont proposés.
Costes, Mathilde. "Systèmes de spins de basse dimension : étude sous champ magnétique intense". Toulouse 3, 2005. http://www.theses.fr/2005TOU30151.
Pełny tekst źródłaWe studied magnetic and transport properties under intense magnetic field in low dimensional magnetic spins systems. The frustrated quasi-1D Ising system, A3A'BO6, allows the study of the properties of conduction as well as the analysis of the relation between the magnetic and electronic correlations. The various experimental techniques used, enabled us to highlight important dynamic effects at low temperature for three compounds Ca3Co2O6, Ca3CoIrO6 and Sr3NiIrO6 as well as the close relation between the magnetic and electronic correlations in these compounds. We also probed two Heisenberg systems of spin 1/2. For the vanadate eta-Na1. 286V2O5, magnetization and EPR measurements, permitted to determine the value of the gap predicted by measurements of susceptibility and showed the apparition of a plateau to 1/9 of the saturation magnetization. For CaCu2O3, EPR measurements showed the role of the impurities in the establishment of the order at long distance in the compound
Ferhat, Karim. "Fluctuations quantiques dans des systèmes de spins et de charges en interaction". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAY087/document.
Pełny tekst źródłaThis thesis focuses on two different spin and charge systems, interacting under the effect of quantum fluctuations.The first project highlights the phase diagram of interacting electrons on a kagome lattice. This diagram is driven by two Coulomb repulsions. The first is a on site repulsion, and the second a nearest neighbor one. These two repulsions are in competition with quantum fluctuations of electronic charges. Four phases are depicted, two are unknown and the two other are in agreement with the literature. The two new phases are stabilized in the strong on site repulsion regime. When nearest neighbor repulsions are strong enough to induce a charge local constraint, the system enters in a so called Heisenberg-Loop Phase. These loops are antiferromagnetically arranged and can be described by a Heisenberg-like model in which both charge and spin play surprisingly a role in the exchange interaction. The second new phase is stabilized in the regime where nearest neighbor interactions are too weak to maintain the local constraint. Then, half of the electrons are delocalized in unidimensional Bloch states similar to quantum polarized electronic bubbles. These bubbles are trapped in an inversely polarized electronic cristal formed by the other electrons. This peculiar phase is favored by both quantum charge fluctuations in the bubbles, and antiferromagnetic exchanges between their electrons and the cristal ones.The second project deals with a Terbium Double-Decker molecular magnet. This molecule is modeled by three interacting degrees of freedom. The first is a nuclear spin of the Terbium ion, and the second is the electronic spin of this same ion. The two spins interact via a magnetic exchange.In a first approximation, the effect of the electronic spin is to induce a dipolar field. Finally, the last degree of freedom is carried by two ligands under the influence of the dipolar field. The ligands play the role of a read-out quantum dot, and by conductance measurements through this last one, we can probe the electronic spin and then, the nuclear spin. The first step of this project highlights the modeling of the global system. Then numerical computations are depicted and are in a quantitative agreement with the experimental measurements realized during the thesis of Stefan Thiele and Clément Godfrin.On the other hand, by applying electrical Radio Frequency Fields, we can drive quantum fluctuations on the nuclear spin. This quantum manipulation of the spin is realized by the dynamic deformation of the electron cloud under the effect of the Radio Frequency Field. As a result, we are able to implement a Grover Quantum Algorithm on the nuclear field. This thesis focuses on the realization of a simulation program that was a tool used by Clément Godfrin to successfully implement the Grover Algorithm
Gauthé, Olivier. "Méthodes de réseaux de tenseurs pour les systèmes de spins SU(N)". Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30279.
Pełny tekst źródłaThe study of strongly correlated electron systems is one of the most challenging target of modern condensed matter physics. Beyond the Mott transition, these systems are magnetic insulators that can be described by a spin wavefunction. This concept can be generalized by replacing the spin variable by an irreducible representation of the group SU(N), which is relevant in some cold atomic gases experiments. This thesis aims to determine the physical properties of paradigmatic wavefunctions of condensed matter systems ruled by SU(N) symmetry using tensor network algorithms. These methods have already proven to be efficient to tackle problems with discrete variables on a lattice. Here, the formalism of Projected Entangled Pair States (PEPS) is used to design elementary tensors with intrinsic SU(N) symmetry that describe quantum spin liquid phases. This method is first applied to the generalization to SU(3) symmetry group and in two dimensions on the square lattice of the Affleck-Kennedy-Lieb-Tasaki (AKLT) wavefunction. It is shown to belong to the class of symmetry protected topological phases. Subsequently, the generalization to SU(N) of resonant valence bond (RVB)-like states on the square lattice is investigated, first for staggered fundamental-conjugate representations. A system of two SU(4) fermions per site is then considered and described with generalized RVB wavefunctions. These states are shown to represent a Z2 topological quantum spin liquid, possibly chiral, that does not break any spatial symmetry. A reasonable, short-range Hamiltonian able to stabilize this phase is proposed
Ahmed, Eman Ahmed Sayed. "Modélisation constructive des systèmes à événements discrets. Application aux organismes artificiels". Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4016.
Pełny tekst źródłaHumans can internally sense their muscles. They can also recognize their environment with its objects and are able to navigate through it easily to reach them. How these abilities are gained and interact each other is still an open question in biology. Our aim is to help biologists to understand how a human is able to build his cognitive map and make goal-directed movements. The origin of human capabilities goes back to the fetus stage. We present a theoretical model of the development of the cognitive map of a fetus human from his sensorimotor system. The model integrates the proprioceptions of body limbs and perceptions from the environment and how these cooperate to build a cognitive map, which in turn, is essential for making goal-directed movements to reach different objects in the surrounding environment. We propose a new clustering algorithm called “Frequency-based-means”; which is used to get the proprioceptions and the perceptions that form the association map. Hidden Markov Models are used to model movement learning and production
Wippler, Jean-Luc. "Une approche paradigmatique de la conception architecturale des systèmes artificiels complexes". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX083/document.
Pełny tekst źródłaArchitecting seeks now to be distinct from its original domain, systems engineering, becoming an emergent domain. Far from being recognized as a science or a discipline, its practice is nowadays more and more widespread. However, this practice is still poorly formalized, and insufficiently being taught, lacking a well-established and accessible corpus of knowledge, techniques or approaches.This thesis contributes filling that gap by proposing a paradigm of the architectural design of artificial complex systems. The latter is built based on existing paradigms that are combined, then completed. It aims at providing architects with an effective, even performative framework. It results in an approach of the architectural design structured in four levels.A so-called archetypal level grasps the core principles of any approach of architectural design of artificial complex systems. These principles are derived from various approaches already applied, mainly in the field of system or product design, but also of architectural design of buildings.A so-called general level lies on the principle of a present-future division. In that sense, it differs from engineering approaches that usually rely on a problem-solution dichotomy. It is based on the following main idea: we should consent that when an architect designs, he does not solve problems, but he devises possible and plausible futures, requiring to perceive the present. This vision of the architect's way of working directly impacts the kind of artefacts he handles. We sho how to aggregate these artefacts into models, reflecting either his perception of the present, or his development of futures while progressing through some identified processes.A so-called particular level aims at allowing the storytelling of a given design. To achieve this goal, a notation of the design process is suggested. It lies on some basic mechanisms, one of them being the combination divergence-convergence, called the breathing of the architectural design.At last, a so-called toolbox level, not addressed in this thesis, would consist of various cognitive operations required for the architect in order to accomplish his task of designing (abstraction, questioning, judgement, comparison, decision, etc.)The whole approach is illustrated by an example of an architectural design of a complex system: a Safe City
Robert, Julien. "Systèmes magnétiques à frustration géométrique : approches expérimentale et théorique". Phd thesis, Grenoble 1, 2007. http://www.theses.fr/2007GRE10192.
Pełny tekst źródłaLn this thesis, the magnetic properties of geometrically frustrated systems have been studied, using experimental and theoretical approaches. Ln the manuscript, the study of magnetic lattices based on corner-sharing triangles is reported in three different parts. The first part concerns the La3Cuz VOg compound, formed by weakly coupled frustrated planar clusters, each one being constituted of 9 coupled spins 1/2. Ln this system, different regimes are successively stabilized when the temperature is decreased: the high temperature paramagnetic regime of individual spins is followed by a paramagnetic regime of collective pseudo-spins 1/2 associated to each cluster below 20 K. Finally, short range inter-cluster correlations emerge below 2 K, indicating a hierarchical rise of the correlations. The following parts are dedicated to the study of the dynamical properties of the kagomé lattice. We first show that the langasite compound Nd3GasSi014, in which the anisotropic magnetic moments carried by the Nd3+ ions form a kagomé lattice, does not present any magnetic ordering down to 2 K, despite a Curie- Weiss temperature of a few tens of Kelvin. Moreover, we could observe a slowing down of the spin fluctuations below 300 K. Finally, we present a numerical study of the spin dynamics of the Heisenberg antiferromagnet on the kagomé lattice. We show that unexpected coherent excitations develop below T/J=O. OI, in spite of the very short spin-spin correlation length in the system. Ln addition, sorne of the excitations are characterized by a non-uniform distribution of spectral weight. This is understood as an effect of the particular geometry of this network
Darmoul, Saber. "Etude de la contribution des systèmes immunitaires artificiels au pilotage de systèmes de production en environnement perturbé". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2010. http://tel.archives-ouvertes.fr/tel-00719298.
Pełny tekst źródłaZiat, Djamel. "Étude de systèmes magnétiques par rotations de spins de muons et chaleur spécifique". Mémoire, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/10159.
Pełny tekst źródłaLefevre, Alexandre. "Etats métastables dans les systèmes vitreux : des verres de spins aux milieux granulaires". Toulouse 3, 2003. http://www.theses.fr/2003TOU30070.
Pełny tekst źródłaForestier, Guillaume. "Transport quantique dans les verres de spins". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAY023/document.
Pełny tekst źródłaThe experiments presented in this thesis associate two fields of condensed matter physic, on the one hand with the spin glass physic and the other hand with the mesoscopic physic. The spin glass state is one of the most emblematic of disordered and frustred system and at low temperature, it is caracterized by an unconventionel order where the magnetic disorder is quenched. Moroever, it is considered as a model system for glasses in general and thereby it has been extensively studied, both experimentally and theoreticlly. After extensive research efforts, the description of fundamental state of the system has lead towards two well different approaches. The first, given by the mean field solution, highlights a fundamental composed of mulitple states organised and hierarchical. The second, called droplet model is based on the off--equilibrium dynamic of a unique ground state. However, despite these contributions, the understanding ot this phase is far from being complete and the nature of the ground state still remains an open question. In a mesoscopic conductor, the transport of electron is coherent: electrons keep the memory of their phase, so that one can observe interference effects. The main motivation of this work is to use these interference effects in order to to probe the spin glass state. Indeed, as electronic interference depends of the position of the static disorder, coherent transport can be a useful tool to study the configuration of the microscopic disorder. Althought few coherent transport experiments exist to probe the spin glass, this field of research has very little explored. Nevertheless, this area has been a revival thanks to theoritical work, showing how coherent transport is sensitived to the quenched disorder and how it may provide informations of the nature of fundamental state of spin glass. So, this experimental work deals with the implementation of transport measurements in mesoscopic spin glasses. The first part of the study is focused on the general charateristics of classical and quatum transport of these system. We have examined the resistivity as a function of the temperature and magnetic field and we show that these mesoscopic systems have a spin glass-like behaviour. In a second part, we have focused on the low field magnetoresistivity. We show that it presents a strong hysteresis, whose the amplitude is strongly depends, both of the temperature in the glassy phase and sweeping rate of the magnetic field. We argue that this particular behaviour is related to the out off-equilibrium of the system and we show how the temperature and the sweeping rate control the deviation to the equilibrium. In this part, we also examine by transport measurements how the system relaxes towards the equilibrium just after its excitation. In addition, we present surprinsing transport propreties that we observed, resulting of experimental protocols more sophisticated in temperatures and magnetic fields
Roux, Guillaume. "Echelles de spins dopées sous champ magnétique". Phd thesis, Université Paul Sabatier - Toulouse III, 2007. http://tel.archives-ouvertes.fr/tel-00167129.
Pełny tekst źródłade charge et superfluidité est mise en perspective avec les résultats sur les échelles dopées.
Cherrier, Raphaël. "Étude de systèmes de spins complexes ou désordonnés : analogies avec la transition vitreuse structurelle". Phd thesis, Université Paul Sabatier - Toulouse III, 2003. http://tel.archives-ouvertes.fr/tel-00840704.
Pełny tekst źródłaCherrier, Raphaël. "Etude de systèmes de spins complexes ou désordonnés : analogies avec la transition vitreuse structurelle". Toulouse 3, 2003. http://www.theses.fr/2003TOU30136.
Pełny tekst źródłaHoang, Danh tai. "Transition de phase et transport de spin dans des systèmes complexes : systèmes de spins frustrés, cristaux moléculaires et cristaux liquides". Phd thesis, Université de Cergy Pontoise, 2012. http://tel.archives-ouvertes.fr/tel-00867690.
Pełny tekst źródłaREYNAL, SYLVAIN. "Transitions de phase dans les systèmes de spins régis par des interactions à longue portée". Phd thesis, Université de Cergy Pontoise, 2005. http://tel.archives-ouvertes.fr/tel-00010256.
Pełny tekst źródłaMöller, Gunnar. "Espaces dynamiques réduits en physique de la matière condensée :Systèmes à effet Hall bicouches, réduction dimensionnelle et systèmes de spins magnétiques". Phd thesis, Université Paris Sud - Paris XI, 2006. http://tel.archives-ouvertes.fr/tel-00121765.
Pełny tekst źródłaOn introduit une classe générale d'états appariés de fermions composites. Ces fonctions d'onde sont exploitées pour analyser l'état fondamental des systèmes bicouches à effet Hall au facteur de remplissage total un. A partir d'une étude de Monte Carlo variationnel nous concluons que la transition de phase compressible à incompressible observée dans ce système est du deuxième ordre. Nous étudions également la question de l'existence d'un état apparié à demi-remplissage dans les simples couches. Ensuite nous considérons des schémas de réduction dimensionnelle de systèmes bidimensionnels sur la sphère vers des systèmes unidimensionnels sur le cercle. Un tel mapping est établi pour des systèmes libres et un candidat pour un système d'anyons généralisé est proposé. Finalement, nous analysons les systèmes de spins magnétiques sur réseaux bidimensionnels et discutons si un état de glace de spins peut exister en présence d'interactions dipolaires à longue portée.
Dabladji, Rima. "Classification du cancer du sein par des approches basées sur les systèmes immunitaires artificiels". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLE026/document.
Pełny tekst źródłaBreast cancer arrives in the world in first place in terms of incidence and mortality among the different cancer localizations in women. Despite the significant progress made in recent decades to improve the management of this type of cancer, more accurate diagnostic tools are still necessary to help experts fight against this fatal disease. In this context, considerable research studies have been carried out to bring new perspectives for the improvement of the diagnosis of breast cancer, by developing Computer-Aided Diagnosis systems (CAD). Many works were directed to detecting the presence of cancerous tissues in the breast and tumor classification using tools from artificial intelligence often inspired by natural systems. In this case, Artificial Immune Systems (AIS) are a research field that bridges the fields of immunology, computer science and engineering. The main developments in artificial immune systems, have focused on three main immunological theories: clonal selection, immune networks and negative selection. We focus in this work on the use of clonal selection algorithms for classification of breast cells in Benign / Malignant. Indeed, these approaches are generally based on two main processes: the shape recognition of the antigen and selection of the specific memory cell to it. The established idea is that only memory cells capable of recognizing the antigen are selected for cloning and mutation. After introducing the principle of these algorithms we will study, through various approaches, their performances. First, we focus on improving CLONALG algorithm, which is a basic algorithm in the field of artificial clonal selection. To enhance the learning of the latter, with a better initialization and controlled diversity, three different methods are proposed appointed Median Filter Clonal ALGorithm (MF-CLONALG), Average Cells Clonal ALGorithm (AC-CLONALG) and Validity Interval Clonal Selection (VI-CS). However, although successful, these approaches require significant computing time. In this context, the second proposed approach aims at reducing the computational rates of these algorithms (and those of the AIS in general) without affecting their performance. The Local Database Categorization Artificial Immune System algorithm (LDC-AIS) uses clustering by K-means for local data categorization, and RBF neural network for learning categories, to accelerate the selection process. The last part of the thesis is dedicated to multimodal optimization. Indeed, after having presented the clonal selection algorithms as competitive tools of pattern recognition and classification, we were interested in exploring this concept, to demonstrate the benefits of cloning and mutation operators in functions optimization’s framework. In response to some drawbacks of the MLP neural network (Multi-Layer Perceptron), an optimization procedure in several stages is proposed, in which the back-propagation is assisted by cloning and mutation processes, for fast and accurate convergence of MLP. Being close to evolutionary techniques, the Multi-Layer Perceptron based Clonal Selection approach (MLP-CS) is compared to an MLP optimized by a genetic algorithm. Each of the approaches proposed in this work is tested and compared to different previous works using two different breast databases which are the Wisconsin Diagnostic Breast Cancer (WDBC), and the Digital Database for Screening Mammography (DDSM)
Ratiéville, Matthieu. "Prévisions de champ moyen détaillées sur des systèmes désordonnés". Paris 6, 2003. http://www.theses.fr/2003PA066280.
Pełny tekst źródłaFeldner, Hélène. "Propriétés magnétiques de systèmes à deux dimensions : système frustré de spins sur réseau carré et propriétés magnétiques de systèmes finis de graphènes". Strasbourg, 2011. http://www.theses.fr/2011STRA6180.
Pełny tekst źródłaThis thesis is about the magnetic properties of two different two dimensional systems. The first one corresponds to vanadates or cuprate crystals, which can be studied by a spin system on square lattice and a Heisenberg model with three couplings, a ferromagnetic first neighbor coupling and antiferromagnetic second and third neighbor couplings. This system is frustrated and lead to a non trivial classical phase diagram. We have studied the influence of quantum fluctuation using a Holstein-Primakov approach and the Schwinger bosons model. The second system studied corresponds to graphene of finite size. To study this system we use a mean field approximation of the Hubbard model. In a first step we recover within our method well known results and check that the model has been correctly implemented. In a second step, in order to assess the accuracy of this method, we perform complementary exact diagonalization calculations, and compare our results with quantum Monte Carlo simulations. And in the last part we will show evidence of a dynamical signature of the zigzag edge magnetization of finite sample of graphene
Hoang, Thi thanh ha. "Un modèle multi-agent récursif générique pour simplifier la supervision de systèmes complexes artificiels décentralisés". Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00744444.
Pełny tekst źródłaCol, Perrine. "Systèmes artificiels de type donneur-accepteur d’électrons : les zéolithes pour la conversion de l’énergie lumineuse". Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10198/document.
Pełny tekst źródłaAn interesting property of zeolites is to generate long-lived charge separated states after spontaneous or photoinduced ionization of adsorbed molecules. The objective of this PhD work is to valorize this phenomenon. At first, we study the adsorption and the ionization of para-quaterphenyl adsorbed in the channels of ZSM-5. This one induces the formation of a radical cation, and a very stable electron-hole pair by indirect recombination of the radical. Then, in order to recover the ejected electrons, we use another electron donor molecule (para-terphenyl) with two electron acceptor molecules: dicyanoethylene and dicyanobenzene. The samples, in particular characterized by diffuse reflectance UV-visible absorption spectroscopy, Raman scattering spectroscopy, and electron paramagnetic resonance showed that the structure of dicyanobenzene allows increasing stabilization of charge separated states, with a location of the ejected electron near molecule. In order to enhance these results, it’s very interesting to transfer electrons to nanoparticles of TiO2 plugged at the pore entry. Thus, we used an electron acceptor molecule with similar structure of dicyanobenzene but able to form a chemical bond with TiO2 through a carboxyl group: the cyanobenzoic acid. One part of the study is thus the acceptor grafting on the TiO2 nanoparticles. We also studied the adsorption of para-terphenyl in nanosheets ZSM-5, a new zeolitic material with great potential
Hoang, Thi Thanh Ha. "Un modèle multi-agent récursif générique pour simplifier la supervision de systèmes complexes artificiels décentralisés". Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENM033/document.
Pełny tekst źródłaObservation of large scale artificials systems is difficult because of their dimension and their openness. This thesis proposes a model SMA-R (Recursive Multi-Agent Systems) based on recursion for multi-level observation of artificial complex systems. From a given SMA, this model is able to build multi-level of abstractions. The model's agent has a module containning knowledge, skills and context of recursion, an eye to observe changes; two mechanisms to build or destroy an abstract level, a module of recursive interaction to support collective and individual behaviors. For applying this model to SMA physically decentralized, we proposed a generic decentralized architecture for recursive agent by adopting the concepts of the OSI model which offerts forward capabilities that we look for: multi-level encapsulation, exchange of virtual and physical messages ... A generic decentralized framework was developed allowing applicatives agents to build multi-levels observation. This framework is applied to the observation of a wireless sensor network
Dimo, Panjio Claude. "Étude des modèles de Richardson-Gaudin de spin-½ avec champ magnétique arbitraire". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0154.
Pełny tekst źródłaThis thesis is divided into three parts and extended over seven chapters between the general introduction and conclusion. Indeed, the first part, consisting of four chapters, is mainly focused on a static study of Richardson-Gaudin models of spin 1/2 with arbitrary magnetic field including the possibility of a totally anisotropic XYZ coupling such that the terms "S^x_jS^x_k , S^y_j S^y_k mathrm{and} S^z_j S^z_k" all have distinct coupling strengths. In this part we determine generically the energy spectrum, the central spin mean values, the wave functions and the two-point correlation functions of the considered models; which will be useful for an advanced dynamical analysis of these models. The calculation of the energy spectrum of the current system can exploit its integrability which is materialized by a set of equations constituting the integrability condition. This calculation is done independently of the symmetry of the model considered and involves the resolution of a system of quadratic equations that is relatively simple to solve numerically.The second part focuses on some examples of applications that could be implemented on the basis of the results obtained in part I. Indeed, it has recently been shown that the XX central spin model is integrable. It describes a particular spin coupled via XX spin-spin couplings to a bath of other spins while feeling a magnetic field along the "hat{z}" axis, i.e. perpendicular to the plane in which the coupling exists. What interests us here is first to demonstrate that the XX central spin model remains integrable in the presence of an arbitrarily oriented magnetic field. In a second step we study whether the dark states remain in this case. The U(1) symmetry of the considered model is broken by the addition of an external field component in the XY plane, which could lead to a radically different physics. Nevertheless, we show that, for a sufficiently strong coupling, the structure of the dark states reappears even in the presence of a magnetic field in the plane. A simple understanding of this result and the demonstration of the universality of the results by a finite size scale study and for a variety of distinct distributions of the coupling constants at the different spins of the bath. Another example of application which closes this second part is that of the XXX dark states with arbitrary magnetic field. These states, although having a different physics from the one encountered in the previously studied models, exist and a generic law has been established to count them.This law has been verified up to 12 spins in the bath, so we can assume that it also works beyond 12 spins in the bath, we can conjecture that it is valid for any value of N.The third part of this project is dedicated to a dynamic study of non-integrable models similar to those studied in the first part of this manuscript. Indeed, these models are just the representation of Richardson-Gaudin models immersed in a time dependent magnetic field oriented along "hat{z}".In a process of rotation around the "hat{z}" axis of the magnetic field associated to the central spin, it is possible to define a time dependent basis in which the time dependent problem reduces to an independent problem. The resulting Hamiltonian can then be integrable and require the use of the results found in the first part to be solved. For these models, by imagining for example that the system is initially prepared in a dark state of the static Hamiltonian, we clearly see that its dynamics is not trivial and leads to perfect oscillations of this state.Finite size systems resulting from the central spin models treated in this thesis depend strongly on the distribution of couplings between the central spin and each nuclear spin constituting the bath
Melotti, Paul. "Modèles intégrables de spins, vertex et boucles". Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS258.
Pełny tekst źródłaThis thesis deals with several problems in statistical mechanics, related to the study of integrable models. In these models, some particular symmetries, like those expressed by the Yang-Baxter equations or "star-triangle'' transformations, lead to the existence of exact formulas for observables of interest.In a first part, we study the star-triangle transformation of the Ising model, recast into a singe polynomial evolution equation by Kashaev. We show that this evolution creates combinatorial objects: C2(1) loop models. We show some limit shapes results and compute the free energy of these loop models. In a second part, we develop the study of the ``eight-vertex'' model, that generalises ice models. In the free-fermion regime, we translate these models into dimers on a bipartite graph, and use the strong integrability structures of these. We deduce the construction of Gibbs measures and correlations in infinite volume, in particular for Z-invariant regimes on isoradial graphs. Finally, we suggest interpretations of the Yang-Baxter equations in discrete geometry, via particular embeddings of graphs
Barotto, Béatrice. "Introduction de paramètres stochastiques pour améliorer l'estimation des trajectoires d'un système dynamique par une méthode de moindres carrés : application à la détermination de l'orbite d'un satellite avec une précision centimétrique". Toulouse 3, 1995. http://www.theses.fr/1995TOU30196.
Pełny tekst źródłaBelliard, Samuel. "Applications de l'ansatz de Bethe Algébrique et au-delà". Chambéry, 2009. http://www.theses.fr/2009CHAMS037.
Pełny tekst źródłaIn this thesis, we will discuss quantum integrable systems and spin chains. We will present the notion of quantum integrability and a related algebraic structure, the quantum group. This study allows us to introduce the « universal» spin chains used by the Annecy group few years ago. These « universal » chains encompass all the spins chains studied in the literature. The purpose of this thesis is to evaluate, with the algebraic Bethe ansatz (ABA), the eigenvalues and eigenvectors of these « universal» spins chains. We will discuss the case of closed and open spin chains. This study will highlight the limit of the ABA for open spins chains and we will present a new mathematical framework that may allow to find the spectral problem in this case. We will also discuss the computation of the scalar product between two eigenvectors obtained with the ABA
Bouzerar, Richard. "Théorie pour les systèmes désordonnés de spins localisés en interaction avec des porteurs itinérants : les semiconducteurs magnétiques dilués". Phd thesis, Université de Picardie Jules Verne, 2008. http://tel.archives-ouvertes.fr/tel-00367282.
Pełny tekst źródłaSaïghi, Sylvain. "SYSTÈMES NEUROMORPHIQUES ANALOGIQUES : CONCEPTION ET USAGES". Habilitation à diriger des recherches, Université Sciences et Technologies - Bordeaux I, 2011. http://tel.archives-ouvertes.fr/tel-01017791.
Pełny tekst źródłaCantillo, Juan. "Codage multi-couches pour systèmes de communication par satellites". Phd thesis, Paris, ENST, 2008. https://pastel.hal.science/pastel-00005209.
Pełny tekst źródłaThis thesis addresses the error control problem for satellite links from the perspective of cross-layer design. At the crossroads of qos-related constraints, devices complexity and efficient spectrum use, error control is indeed a key aspect of wireless communications - particularly crucial in the satellite context - where cross-layer enhancements can play an important role. After a thorough introduction to cross-layer design, the first part of this work focuses specifically on the error control strategy of early DVB satellites, where redundancies between the channel decoder and the adaptation layers are set to light in order to propose a joint bandwidth-efficient error control policy. The focus then moves to second-generation DVB satellites and the definition of the novel, IP-centric and cross-layer friendly GSE encapsulation protocol, where results from the aforementioned study were successfully applied. Finally, a whole new cross-layer framework called HERACLES is introduced, offering efficient and overhead-free error correction capabilities for almost any layer of a protocol stack and being patented at the moment of writing these words. The results of the overall work show the strengths of an integrated approach to error control, and open the way for innovative cross-layer mechanisms to be deployed in next-generation communications networks
Cantillo, Juan. "Codage multi-couches pour systèmes de communication par satellites". Phd thesis, Télécom ParisTech, 2008. http://pastel.archives-ouvertes.fr/pastel-00005209.
Pełny tekst źródłaAttik, Mohammed. "Traitement intelligent de données par réseaux de neurones artificiels : application à la valorisation des systèmes d'information géographiques". Nancy 1, 2006. http://docnum.univ-lorraine.fr/public/SCD_T_2006_0211_ATTIK.pdf.
Pełny tekst źródłaThe purpose of this thesis is: (i) establish predictive maps on ore deposits, (ii) select a subset of descriptive features that effectively contribute to the building of these predictive maps, (iii) identify and interpret dependencies between the selected features, (iv) place the features into a hierarchy that indicates their importance. A real-life data of Geographical Information System provided by the French geological survey (BRGM) have been used in the accomplished experiments. In order to establish predictive maps, we have used neural network ensemble which is a very successful technique where outputs of a set of separately trained neural network are combined to form one unified prediction. This technique generates several predictive maps following the used aggregation function. In addition, to understand domain data, we have focused on selecting a subset of relevant features. We have proposed an improvement of existing features selection techniques that are based on the principle of Optimal Brain Damage (OBD) as well as those of Optimal Brain Surgeon (OBS) and Mutual Information (MI). We have also proposed novel solutions to understand data that combine ensemble feature selection approach with either concept lattices or statistic techniques. The latter solutions help discovering all relevant features and organizing them into hierarchy according to their concurrencies in the selected subsets of features. Moreover, we have addressed the problem of clustering-based analysis of data provided with multiple labels. The proposed approach uses new measures that extend the scope of the recall and precision measures in information retrieval (IR) to the processing of multi-label data. Experiments have been carried out on data pertaining to geographical information system and documentary system have highlighted the accuracy of our approach for knowledge extraction
Baseilhac, Pascal. "Approche à la Onsager en systèmes intégrables". Habilitation à diriger des recherches, Université François Rabelais - Tours, 2010. http://tel.archives-ouvertes.fr/tel-00612887.
Pełny tekst źródłaMétris, Gilles. "Théorie du mouvement du satellite artificiel : développement des équations du mouvement moyen : application à l'étude des longues périodes". Observatoire de Paris, 1991. http://www.theses.fr/1991OBSP0036.
Pełny tekst źródłaMichéa, Sébastien. "Quelques applications des groupes de Lie de dimension infinie en systèmes de spins et en théorie topologique des champs". Dijon, 1999. http://www.theses.fr/1999DIJOS002.
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