Rozprawy doktorskie: „Functional Matching”

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Sheldrake, Simon N. "Extending functional databases for use in text-intensive applications". Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/34644.

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This thesis continues research exploring the benefits of using functional databases based around the functional data model for advanced database applications-particularly those supporting investigative systems. This is a growing generic application domain covering areas such as criminal and military intelligence, which are characterised by significant data complexity, large data sets and the need for high performance, interactive use. An experimental functional database language was developed to provide the requisite semantic richness. However, heavy use in a practical context has shown that language extensions and implementation improvements are required-especially in the crucial areas of string matching and graph traversal. In addition, an implementation on multiprocessor, parallel architectures is essential to meet the performance needs arising from existing and projected database sizes in the chosen application area.

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Elgedawy, Islam Moukhtar, i islam_elgedawy@yahoo com au. "Correctness-Aware High-Level Functional Matching Approaches For Semantic Web Services". RMIT University. Computer Science and Information Technology, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070511.162143.

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Existing service matching approaches trade precision for recall, creating the need for humans to choose the correct services, which is a major obstacle for automating the service matching and the service aggregation processes. To overcome this problem, the matchmaker must automatically determine the correctness of the matching results according to the defined users' goals. That is, only service(s)-achieving users' goals are considered correct. This requires the high-level functional semantics of services, users, and application domains to be captured in a machine-understandable format. Also this requires the matchmaker to determine the achievement of users' goals without invoking the services. We propose the G+ model to capture the high-level functional specifications of services and users (namely goals, achievement contexts and external behaviors) providing the basis for automated goal achievement determination; also we propose the concepts substitutability graph to capture the application domains' semantics. To avoid the false negatives resulting from adopting existing constraint and behavior matching approaches during service matching, we also propose new constraint and behavior matching approaches to match constraints with different scopes, and behavior models with different number of state transitions. Finally, we propose two correctness-aware matching approaches (direct and aggregate) that semantically match and aggregate semantic web services according to their G+ models, providing the required theoretical proofs and the corresponding verifying simulation experiments.

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Milette, Greg P. "Analogical matching using device-centric and environment-centric representations of function". Link to electronic thesis, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-050406-145255/.

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Thesis (M.S.)--Worcester Polytechnic Institute.
Keywords: Analogy, Design, Functional Modeling, Functional Reasoning, Knowledge Representation, Repertory Grid, SME, Structure Mapping Engine, AI in design. Includes bibliographical references (p.106).

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Corman, Etienne. "Functional representation of deformable surfaces for geometry processing". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX075/document.

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La création et la compréhension des déformations de surfaces sont des thèmes récurrent pour le traitement de géométrie 3D. Comme les surfaces lisses peuvent être représentées de multiples façon allant du nuage de points aux maillages polygonales, un enjeu important est de pouvoir comparer ou déformer des formes discrètes indépendamment de leur représentation. Une réponse possible est de choisir une représentation flexible des surfaces déformables qui peut facilement être transportées d'une structure de données à une autre.Dans ce but, les "functional map" proposent de représenter des applications entre les surfaces et, par extension, des déformations comme des opérateurs agissant sur des fonctions. Cette approche a été introduite récemment pour le traitement de modèle 3D, mais a été largement utilisé dans d'autres domaines tels que la géométrie différentielle, la théorie des opérateurs et les systèmes dynamiques, pour n'en citer que quelques-uns. Le principal avantage de ce point de vue est de détourner les problèmes encore non-résolus, tels que la correspondance forme et le transfert de déformations, vers l'analyse fonctionnelle dont l'étude et la discrétisation sont souvent mieux connues. Cette thèse approfondit l'analyse et fournit de nouvelles applications à ce cadre d'étude. Deux questions principales sont discutées.Premièrement, étant donné deux surfaces, nous analysons les déformations sous-jacentes. Une façon de procéder est de trouver des correspondances qui minimisent la distorsion globale. Pour compléter l'analyse, nous identifions les parties les moins fiables du difféomorphisme grâce une méthode d'apprentissage. Une fois repérés, les défauts peuvent être éliminés de façon différentiable à l'aide d'une représentation adéquate des champs de vecteurs tangents.Le deuxième développement concerne le problème inverse : étant donné une déformation représentée comme un opérateur, comment déformer une surface en conséquence ? Dans une première approche, nous analysons un encodage de la structure intrinsèque et extrinsèque d'une forme en tant qu'opérateur fonctionnel. Dans ce cadre, l'objet déformé peut être obtenu, à rotations et translations près, en résolvant une série de problèmes d'optimisation convexe. Deuxièmement, nous considérons une version linéarisée de la méthode précédente qui nous permet d'appréhender les champs de déformation comme agissant sur la métrique induite. En conséquence la résolution de problèmes difficiles, tel que le transfert de déformation, sont effectués à l'aide de simple systèmes linéaires d'équations
Creating and understanding deformations of surfaces is a recurring theme in geometry processing. As smooth surfaces can be represented in many ways from point clouds to triangle meshes, one of the challenges is being able to compare or deform consistently discrete shapes independently of their representation. A possible answer is choosing a flexible representation of deformable surfaces that can easily be transported from one structure to another.Toward this goal, the functional map framework proposes to represent maps between surfaces and, to further extents, deformation of surfaces as operators acting on functions. This approach has been recently introduced in geometry processing but has been extensively used in other fields such as differential geometry, operator theory and dynamical systems, to name just a few. The major advantage of such point of view is to deflect challenging problems, such as shape matching and deformation transfer, toward functional analysis whose discretization has been well studied in various cases. This thesis investigates further analysis and novel applications in this framework. Two aspects of the functional representation framework are discussed.First, given two surfaces, we analyze the underlying deformation. One way to do so is by finding correspondences that minimize the global distortion. To complete the analysis we identify the least and most reliable parts of the mapping by a learning procedure. Once spotted, the flaws in the map can be repaired in a smooth way using a consistent representation of tangent vector fields.The second development concerns the reverse problem: given a deformation represented as an operator how to deform a surface accordingly? In a first approach, we analyse a coordinate-free encoding of the intrinsic and extrinsic structure of a surface as functional operator. In this framework a deformed shape can be recovered up to rigid motion by solving a set of convex optimization problems. Second, we consider a linearized version of the previous method enabling us to understand deformation fields as acting on the underlying metric. This allows us to solve challenging problems such as deformation transfer are solved using simple linear systems of equations

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Karlaftis, Vasileios Misak. "Structural and functional brain plasticity for statistical learning". Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/278790.

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Extracting structure from initially incomprehensible streams of events is fundamental to a range of human abilities: from navigating in a new environment to learning a language. These skills rely on our ability to extract spatial and temporal regularities, often with minimal explicit feedback, that is known as statistical learning. Despite the importance of statistical learning for making perceptual decisions, we know surprisingly little about the brain circuits and how they change when learning temporal regularities. In my thesis, I combine behavioural measurements, Diffusion Tensor Imaging (DTI) and resting-state fMRI (rs-fMRI) to investigate the structural and functional circuits that are involved in statistical learning of temporal structures. In particular, I compare structural connectivity as measured by DTI and functional connectivity as measured by rs-fMRI before vs. after training to investigate learning-dependent changes in human brain pathways. Further, I combine the two imaging modalities using graph theory and regression analyses to identify key predictors of individual learning performance. Using a prediction task in the context of sequence learning without explicit feedback, I demonstrate that individuals adapt to the environment’s statistics as they change over time from simple repetition to probabilistic combinations. Importantly, I show that learning of temporal structures relates to decision strategy that varies among individuals between two prototypical distributions: matching the exact sequence statistics or selecting the most probable outcome in a given context (i.e. maximising). Further, combining DTI and rs-fMRI, I show that learning-dependent plasticity in dissociable cortico-striatal circuits relates to decision strategy. In particular, matching relates to connectivity between visual cortex, hippocampus and caudate, while maximisation relates to connectivity between frontal and motor cortices and striatum. These findings have potential translational applications, as alternate brain routes may be re-trained to support learning ability when specific pathways (e.g. memory-related circuits) are compromised by age or disease.

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Vale, Christopher A. W. "Growth-based computer aided design strategies for multimode waveguide design with the aid of functional blocks". Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52291.

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Thesis (PhD) -- Stellenbosch University, 2001.
Some digitised pages may appear illegible due to the condition of the original hard copy.
ENGLISH ABSTRACT: A new technique for the design of multimode devices in overmoded waveguide is presented. The technique applies the principle of growth-based design and uses a conceptual functional block representation of the design structure to provide necessary flexibility to the design algorithms. Two growth based design strategies are proposed and evaluated. The first uses a generalized synthesis-oriented scanning technique, and the second uses an evolutionary strategy. The techniques provide reliable solutions to a variety of multimode design problems. In order to facilitate sufficiently fast numerical analysis, novel enhancements of the mode matching technique are developed and the use of surrogate models is investigated. In addition, to allow physical evaluation of the finished devices, original techniques of measuring multimode devices are formulated and utilised. Two practical problems are used to evaluate the performance of the design procedures. The first is the design of overmoded waveguide chokes for microwave heating facilities, and the second is the design of multimode horns for antenna and spatial power combining applications. Various examples of each type of problem are presented with measurements of manufactured solutions.
AFRIKAANSE OPSOMMING: ’n Nuwe tegniek vir die ontwerp van multimodusstelsels binne multimodus golfleier word voorgestel. Die tegniek maak gebruik van die beginsel van groei-georienteerde ontwerp en ontgin ’n konsepsuele funksionele module-voorstelling van die ontwerpstruktuur om die nodige buigsaamheid aan die ontwerpsalgoritmes te verleen. Twee groei-georienteerde ontwerpstrategiee word aangebied en geevalueer. Die eerste is gebasseer op ’n veralgemeende sintese-georienteerde skandeertegniek, en die tweede maak gebruik van ’n evolusie-strategie. Die tegniek verskaf betroubare oplossings vir ’n verskeidenheid van multimodusontwerpsprobleme. Ten einde ’n numeriese analise-tegniek daar te stel wat vinnig genoeg is, word oorspronklike verbeterings van die modal-pas metode ontwikkel en surrogaatmodelle is ook ondersoek. Verder, vir fisiese evaluasie, word oorspronklike meettegnieke vir multimodusstelsels geformuleer en gebruik. Twee praktiese probleme word gebruik om die ontwerpprosedures te evalueer. Die eerste is die ontwerp van multimodus golfleierdrywingsdempers vir mikrogolfverhitting, en die tweede is die ontwerp van multimodus horings vir antenna- en ruimtelike drywingskombineerdertoepasings. Verskeie voorbeelde van elke tipe probleem word gegee met metings van gei'mplementeerde oplossings.

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Bakhtiari, Nejad Marjan. "Dynamics of Multi-functional Acoustic Holograms in Contactless Ultrasonic Energy Transfer Systems". Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/102414.

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Contactless ultrasonic power transfer (UPT), using piezoelectric transducers, is based on transferring energy using acoustic waves, in which the waves are generated by an acoustic source or transmitter and then transferred through an acoustic medium such as water or human tissue to a sensor or receiver. The receiver then converts the mechanical strain induced by the incident acoustic waves to electricity and delivers to an electrical load, in which the electrical power output of the system can be determined. The execution and efficiency of this technology can be significantly enhanced through patterning, focusing, and localization of the transmitted acoustic energy in space to simultaneously power pre-determined distributed sensors or devices. A passive 3D-printed acoustic hologram plate alongside a single transducer can generate arbitrary and pre-designed ultrasound fields in a particular distance from the hologram mounted on the transmitter, i.e., a target plane. This dissertation presents the use of these simple, cost-effective, and high-fidelity acoustic holograms in UPT systems to selectively enhance and pattern the electrical power output from the receivers. Different holograms are numerically designed to create single and multi-focal pressure patterns in a target plane where an array of receivers are placed. The incident sound wave from a transmitter, after passing through the hologram, is manipulated, hence, the output field is the desired pressure field, which excites the receivers located at the pre-determined focal points more significantly. Furthermore, multi-functional holograms are designed to generate multiple images at different target planes and driving frequencies, called, respectively, multi-image-plane and multi-frequency patterning holograms. The multiple desired pressure distributions are encoded on the single hologram plate and each is reconstructed by changing the axial distance and by switching the frequency. Several proof-of-concept experiments are performed to verify the functionality of the computationally designed holograms, which are fabricated using modern 3D-printers, i.e., the desired wavefronts are encoded in the hologram plates' thickness profile, being input to the 3D-printer. The experiments include measurement of output pressure fields in water using needle hydrophones and acquisition of receivers' voltage output in UPT systems. Another technique investigated in this dissertation is the implementation of acoustic impedance matching layers deposited on the front leading surface of the transmitter and receiver transducers. Current UPT systems suffer from significant acoustic losses through the transmission line from a piezoelectric transmitter to an acoustic medium and then to a piezoelectric receiver. This is due to the unfavorable acoustic impedance mismatch between the transducers and the medium, which causes a narrow transducer bandwidth and a considerable reflection of the acoustic pressure waves at the boundary layers. Using matching layers enhance the acoustic power transmission into the medium and then reinforce the input as an excitation into the receiver. Experiments are performed to identify the input acoustic pressure from a cylindrical transmitter to a receiver disk operating in the 33-mode of piezoelectricity. Significant enhancements are obtained in terms of the receiver's electrical power output when implementing a two-layer matching structure. A design platform is also developed that can facilitate the construction of high-fidelity acoustically matched transducers, that is, the material layers' selection and determination of their thicknesses. Furthermore, this dissertation presents a numerical analysis for the dynamical motions of a high-intensity focused ultrasound (HIFU)-excited microbubble or stable acoustic cavitation, which includes the effects of acoustic nonlinearity, diffraction, and absorption of the medium, and entails the problem of several biomedical ultrasound applications. Finally, the design and use of acoustic holograms in microfluidic channels are addressed which opens the door of acoustic patterning in particle and cell sorting for medical ultrasound systems.
Doctor of Philosophy
This dissertation presents several techniques to enhance the wireless transfer of ultrasonic energy in which the sound wave is generated by an acoustic source or transmitter, transferred through an acoustic medium such as water or human tissue to a sensor or receiver. The receiver transducer then converts the vibrational energy into electricity and delivers to an electrical load in which the electrical power output from the system can be determined. The first enhancement technique presented in this dissertation is using a pre-designed and simple structured plate called an acoustic hologram in conjunction with a transmitter transducer to arbitrarily pattern and shape ultrasound fields at a particular distance from the hologram mounted on the transmitter. The desired wavefront such as single or multi-focal pressure fields or an arbitrary image such as a VT image pattern can simply be encoded in the thickness profile of this hologram plate by removing some of the hologram material based on the desired shape. When the sound wave from the transmitter passes this structured plate, it is locally delayed in proportion to the hologram thickness due to the different speed of sound in the hologram material compared to water. In this dissertation, various hologram types are designed numerically to implement in the ultrasonic power transfer (UPT) systems for powering receivers located at the predetermined focal points more significantly and finally, their functionality and performances are verified in several experiments. Current UPT systems suffer from significant acoustic losses through the transmission from a transmitter to an acoustic medium and then to a receiver due to the different acoustic impedance (defined as the product of density and sound speed) between the medium and transducers material, which reflects most of the incident pressure wave at the boundary layers. The second enhancement technology addressed in this dissertation is using intermediate materials, called acoustic impedance matching layers, bonded to the front side of the transmitter and receiver face to alleviate the acoustic impedance mismatch. Experiments are performed to identify the input acoustic pressure from a transmitter to a receiver. Using a two-layer matching structure, significant enhancements are observed in terms of the receiver's electrical power output. A design platform is also developed that can facilitate the construction of high-fidelity acoustically matched transducers, that is, the material layers' selection and determination of their thicknesses. Furthermore, this dissertation presents a numerical analysis for the dynamical motions of a microbubble exposed to a high-intensity focused ultrasound (HIFU) field, which entails the problem of several biomedical ultrasound applications such as microbubble-mediated ultrasound therapy or targeted drug delivery. Finally, an enhancement technique involving the design and use of acoustic holograms in microfluidic channels is addressed which opens the door of acoustic patterning in particle and cell sorting for medical ultrasound systems.

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Källberg, David. "Nonparametric Statistical Inference for Entropy-type Functionals". Doctoral thesis, Umeå universitet, Institutionen för matematik och matematisk statistik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-79976.

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In this thesis, we study statistical inference for entropy, divergence, and related functionals of one or two probability distributions. Asymptotic properties of particular nonparametric estimators of such functionals are investigated. We consider estimation from both independent and dependent observations. The thesis consists of an introductory survey of the subject and some related theory and four papers (A-D). In Paper A, we consider a general class of entropy-type functionals which includes, for example, integer order Rényi entropy and certain Bregman divergences. We propose U-statistic estimators of these functionals based on the coincident or epsilon-close vector observations in the corresponding independent and identically distributed samples. We prove some asymptotic properties of the estimators such as consistency and asymptotic normality. Applications of the obtained results related to entropy maximizing distributions, stochastic databases, and image matching are discussed. In Paper B, we provide some important generalizations of the results for continuous distributions in Paper A. The consistency of the estimators is obtained under weaker density assumptions. Moreover, we introduce a class of functionals of quadratic order, including both entropy and divergence, and prove normal limit results for the corresponding estimators which are valid even for densities of low smoothness. The asymptotic properties of a divergence-based two-sample test are also derived. In Paper C, we consider estimation of the quadratic Rényi entropy and some related functionals for the marginal distribution of a stationary m-dependent sequence. We investigate asymptotic properties of the U-statistic estimators for these functionals introduced in Papers A and B when they are based on a sample from such a sequence. We prove consistency, asymptotic normality, and Poisson convergence under mild assumptions for the stationary m-dependent sequence. Applications of the results to time-series databases and entropy-based testing for dependent samples are discussed. In Paper D, we further develop the approach for estimation of quadratic functionals with m-dependent observations introduced in Paper C. We consider quadratic functionals for one or two distributions. The consistency and rate of convergence of the corresponding U-statistic estimators are obtained under weak conditions on the stationary m-dependent sequences. Additionally, we propose estimators based on incomplete U-statistics and show their consistency properties under more general assumptions.

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Harvey, Nicholas James Alexander. "Matchings, matroids and submodular functions". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44416.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.
Includes bibliographical references (p. 111-118).
This thesis focuses on three fundamental problems in combinatorial optimization: non-bipartite matching, matroid intersection, and submodular function minimization. We develop simple, efficient, randomized algorithms for the first two problems, and prove new lower bounds for the last two problems. For the matching problem, we give an algorithm for constructing perfect or maximum cardinality matchings in non-bipartite graphs. Our algorithm requires O(n") time in graphs with n vertices, where w < 2.38 is the matrix multiplication exponent. This algorithm achieves the best-known running time for dense graphs, and it resolves an open question of Mucha and Sankowski (2004). For the matroid intersection problem, we give an algorithm for constructing a common base or maximum cardinality independent set for two so-called "linear" matroids. Our algorithm has running time O(nrw-1) for matroids with n elements and rank r. This is the best-known running time of any linear matroid intersection algorithm. We also consider lower bounds on the efficiency of matroid intersection algorithms, a question raised by Welsh (1976). Given two matroids of rank r on n elements, it is known that O(nr1.5) oracle queries suffice to solve matroid intersection. However, no non-trivial lower bounds are known. We make the first progress on this question. We describe a family of instances for which (log2 3)n - o(n) queries are necessary to solve these instances. This gives a constant factor improvement over the trivial lower bound for a certain range of parameters. Finally, we consider submodular functions, a generalization of matroids. We give three different proofs that [omega](n) queries are needed to find a minimizer of a submodular function, and prove that [omega](n2/ log n) queries are needed to find all minimizers.
by Nicholas James Alexander Harvey.
Ph.D.

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Ibrahim, Mazher Hassan. "History matching pressure response functions from production data". Texas A&M University, 2004. http://hdl.handle.net/1969.1/1486.

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This dissertation presents several new techniques for the analysis of the long-term production performance of tight gas wells. The main objectives of this work are to determine pressure response function for long-term production for a the slightly compressible liquid case, to determine the original gas in place (OGIP) during pseudosteady state (PSS), to determine OGIP in the transient period, and to determine the effects of these parameters on linear flow in gas wells. Several methods are available in the industry to analyze the production performance of gas wells. One common method is superposition time. This method has the advantage of being able to analyze variable-rate and variable-pressure data, which is usually the nature of field data. However, this method has its shortcomings. In this work, simulation and field cases illustrate the shortcomings of superposition. I present a new normalized pseudotime plotting function for use in the superposition method to smooth field data and more accurately calculate OGIP. The use of this normalized pseudotime is particularly important in the analysis of highly depleted reservoirs with large change in total compressibility where the superposition errors are largest. The new tangent method presented here can calculate the OGIP with current reservoir properties for both constant rate and bottomhole flowing pressure (pwf) production. In this approach pressure-dependent permeability data can be integrated into a modified real gas pseudopressure,m(p), which linearizes the reservoir flow equations and provides correct values for permeability and skin factor. But if the customary real-gas pseudopressure, m(p) is used instead, erroneous values for permeability and skin factor will be calculated. This method uses an exponential equation form for permeability vs. pressure drop. Simulation and field examples confirm that the new correction factor for the rate dependent problem improves the linear model for both PSS and transient period, whether plotted on square-root of time or superposition plots.

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Dondé-Coquelet, Clément. "Caractérisation du fonctionnement du système auditif central associé aux performances d’appariement tonal chez les sujets atteints de schizophrénie : approches psychophysiques et neurophysiologiques". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1162.

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La schizophrénie (SZ) est une pathologie psychiatrique chronique et invalidante dont les conséquences fonctionnelles sont principalement liées à des déficits cognitifs. Ceux-ci sont étroitement associés à des déficits de perception auditive précoce d’informations de bas niveaux telle que la hauteur sonore. La perception auditive précoce peut s’évaluer avec un paradigme comportemental simple appelé « tone-matching » (appariement tonal AT), dans le lequel les sujets doivent discriminer activement entre deux sons courts (300-ms) d’une même paire séparés par un intervalle bref (500-ms). Les performances d’AT reflètent un processus cognitif de comparaison préattentionnelle se déroulant au sein du système auditif central (SAC). Le SAC est constitué du noyau géniculé médian du thalamus (MGN), de l’aire corticale auditive précoce (EA) et de l’aire corticale auditive associative (AA). Cependant, les dysfonctionnements du SAC sous-tendant les déficits d’AT dans la SZ restent mal connus. De plus, ces déficits sont élevés mais hétérogènes selon les cohortes. Ce travail de thèse propose de caractériser le fonctionnement du SAC associé aux performances d’AT chez les sujets SZ afin de mieux comprendre la physiopathologie du trouble et de développer des traitements ciblés. L’hypothèse guidant les 4 études expérimentales de ce travail est que des altérations psychophysiques et neurophysiologiques spécifiques du SAC sont impliquées dans les déficits d’AT dans la SZ. Nos études psychophysiques utilisant différents paradigmes de « tone-matching » ont montré 1) un déficit d’AT de magnitude croissante pour l’intensité, la hauteur et la longueur des stimuli auditifs chez les sujets SZ (n=29), 2) un déficit d’appariement de trios de sons médiant une corrélation entre les déficits d’appariement de paires de sons (AT proprement dit) et l’identification de phrases émotionnelles (n=27). Ces résultats démontrent que les sujets SZ présentent différents niveaux de déficits d’AT selon le type de caractéristique acoustique, ainsi que des niveaux de déficits hiérarchiquement organisés entre les types de complexité des stimuli auditifs perçus. 3) Nos approches neurophysiologiques ont montré une distribution bimodale des performances d’AT chez les sujets atteints de SZ (n=310) avec un 1er groupe présentant une réduction significative de ces performances associée à une réduction de la connectivité fonctionnelle de repos à l’IRM entre les différentes régions du SAC (MGN-EA, MGN-AA et EA-AA impliquant particulièrement des sous-régions AA adjacentes à l’EA) et un 2nd ne présentant pas de déficits d’AT mais une réduction plus modérée de la connectivité uniquement entre EA-AA. Ces résultats démontrent que les performances d’AT permettent de séparer deux sous-types de SZ présentant des patterns topographiques spécifiques de dysconnectivité fonctionnelle de repos au sein du SAC. 4) Les résultats préliminaires de l’étude de l’effet d’une procédure de stimulation électrique transcrânienne non invasive (tES) ciblant le SAC gauche (2mA, 10x20min) montrent une modulation significative des performances d’AT après la procédure de stimulation chez les sujets SZ (n=2). Cela suggère que les déficits d’AT pourraient être dépendants de mécanismes d’excitabilité et de plasticité des neurones du SAC modulables par tES. Pris ensembles, ces résultats confirment l’influence d’altérations mécanistiques du SAC sur les déficits d’AT dans la SZ, dont les spécificités anatomo-fonctionnelles seront à confirmer par des études de validation et des explorations neurophysiologiques « temps réel » du SAC en situation d’AT. En perspective, comme les paradigmes de « tone-matching » peuvent être implémentés facilement en pratique clinique, ces nouvelles donnés pourront permettre de différencier facilement des sous-types physiopathologiques de patients, et de développer des approches thérapeutiques ciblées sur le SAC à la fois en tES et en entraînement cognitif sensoriel
Schizophrenia (SZ) is a chronic brain disorder with outcome primarily driven by deficits in cognition. These have been related to impaired discrimination of basic auditory information such as pitch, as assessed in tone-matching behavioral paradigms in which subjects are asked to actively discriminate between two short pure tones (300-ms) following a brief delay (500-ms). More specifically, tone-matching indexes early, pre-attentive comparison mechanisms occurring in the central auditory system (CAS, divided into thalamic medial geniculate nucleus (MGN), early auditory (EA) and association auditory (AA) cortical areas). Therefore, characterisations of the CAS functioning associated with tone-matching abilities in SZ individuals may be useful drivers for pathophysiology understanding and therapeutic development. First, we aimed at exploring tone-matching abilities in SZ across major acoustic features (length, pitch, intensity) and different levels of complexity (2-tones, 3-tones, emotional sentences) using psychophysical testing. We predicted that patients would display differential deficits across acoustic features, and present a mediated relationship between tone-matching levels of complexity. Second, we investigated the CAS functioning associated with tone-matching at a neurophysiological level, using resting-state functional connectivity MRI (rsFC-MRI) and CAS-targeted transcranial electrical stimulation (left fronto-temporal tES, 2mA, random noise current, ten 20-min twice-daily sessions). We predicted that functional dysconnectivity within the CAS would be associated with tone-matching impairments, and that tES would significantly modulate these impairments in patients. As complementary, we reviewed historical aspects of basic auditory explorations in SZ and studies investigating basic auditory-training approaches as a potential remediative treatment. Psychophysical studies demonstrated more prominent deficits for length than pitch and, in turn, than intensity (n=29), and showed that 3-tones discrimination mediates the correlation between 2-tones and auditory emotion recognition deficits (n=27). Neurophysiological approaches showed that tone-matching performances are bimodally distributed across SZ subjects (n=310), with one group (SZ-) showing significant reductions in both tone-matching and rsFC-MRI in regions of the bilateral CAS (i.e., between MGN and both EA and AA, as well as reductions between EA and AA, particularly involving parcels which are immediately adjacent to EA), and one group (SZ+) showing intact tone-matching and significant reductions only in EA-AA connectivity. The investigation of CAS-targeted tES impact on tone-matching abilities in patients is still ongoing, but preliminary results demonstrated significant modulations of tone-matching scores after the tES procedure (n=2). Our results demonstrate that SZ individuals present with different patterns of tone-matching deficits across acoustic features, but similar yet hierarchical levels of impairments for processing of simple vs. more complex auditory stimuli. Nevertheless, both feature- and complexity- dependant tone-matching deficits might be associated with different types of anatomo-functional underpinnings in the CAS. In addition, we showed that tone-matching measure segregates between discrete SZ subgroups presenting distinct topographic patterns of functional dysconnectivity in the CAS. Finally, tone-matching deficits might be related to neuronal excitability and plasticity mechanisms in the SAC that are modulated by tES. As tone-matching paradigms can be readily implemented within routine clinical settings, these experimental results may be useful to permit differentiation of discrete subtypes of SZ and to develop both non-invasive brain stimulation and remediative approaches

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12

Xiao, Dan. "An implementation of kernelization via matchings". Ohio : Ohio University, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1177095339.

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Essaid, Amira. "Decision making for ontology matching under the theory of belief functions". Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S100/document.

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L'appariement des ontologies est une tâche primordiale pour palier au problème d'hétérogénéité sémantique et ainsi assurer une interopérabilité entre les applications utilisant différentes ontologies. Il consiste en la mise en correspondance de chaque entité d'une ontologie source à une entité d'une ontologie cible et ceci par application des techniques d'alignement fondées sur des mesures de similarité. Individuellement, aucune mesure de similarité ne permet d'obtenir un alignement parfait. C'est pour cette raison qu'il est intéressant de tenir compte de la complémentarité des mesures afin d'obtenir un meilleur alignement. Dans cette thèse, nous nous sommes intéressés à proposer un processus de décision crédibiliste pour l'appariement des ontologies. Étant données deux ontologies, on procède à leur appariement et ceci par application de trois techniques. Les alignements obtenus seront modélisés dans le cadre de la théorie des fonctions de croyance. Des règles de combinaison seront utilisées pour combiner les résultats d'alignement. Une étape de prise de décision s'avère utile, pour cette raison nous proposons une règle de décision fondée sur une distance et capable de décider sur une union d'hypothèses. Cette règle sera utilisée dans notre processus afin d'identifier pour chaque entité source le ou les entités cibles
Ontology matching is a solution to mitigate the effect of semantic heterogeneity. Matching techniques, based on similarity measures, are used to find correspondences between ontologies. Using a unique similarity measure does not guarantee a perfect alignment. For that reason, it is necessary to use more than a similarity measure to take advantage of features of each one and then to combine the different outcomes. In this thesis, we propose a credibilistic decision process by using the theory of belief functions. First, we model the alignments, obtained after a matching process, under the theory of belief functions. Then, we combine the different outcomes through using adequate combination rules. Due to our awareness that making decision is a crucial step in any process and that most of the decision rules of the belief function theory are able to give results on a unique element, we propose a decision rule based on a distance measure able to make decision on union of elements (i.e. to identify for each source entity its corresponding target entities)

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Poeschel, Friedrich Gerd. "Signals in two-sided search". Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:c1decfbb-5fdf-4c13-805e-2cc7fe115641.

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We introduce signals to search models of two-sided matching markets and explore the implications for efficiency. In a labour market model in which firms can advertise wages and workers can choose effort, we find that advertisements can help overcome the Diamond paradox. Advertisements fix workers' beliefs, so that workers will react if firms renege on advertisements. Firms then prefer to advertise truthfully. Next, we consider a market with two-sided heterogeneity in which types are only privately observable. We identify a simple condition on the match output function for agents to signal their types truthfully and for the matching to exhibit positive assortative matching despite search frictions. While our theoretical work implies that the efficiency of matching increases as information technology spreads, empirical matching functions typically suggest that it declines. By estimating more general matching functions, we show that the result of declining efficiency can partly be attributed to omitted variable bias.

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TANG, YINGJIE. "ON CLOSE CONTOUR PRESENTATION AND MATCHING PROBLEMS WITH BIOMEDICAL IMAGE APPLICATIONS". University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin983567833.

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Goulnik, Jérémie. "Étude fonctionnelle de la fonction de pollinisation entomophile en prairie permanente sous l'effet d'un gradient d'intensification agricole". Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0297.

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Le déclin de la biodiversité et son impact sur le fonctionnement des écosystèmes sont un enjeu majeur du XXIème siècle. L’agriculture intensive est aujourd’hui considérée comme l’un des facteurs responsables de ce déclin, suscitant une volonté sociétale pour une transition vers l’agroécologie. Celle-ci vise à intégrer les fonctions écologiques dans la production des biens agricoles. Les prairies permanentes sont au cœur de ces enjeux, étant à la fois essentielles pour l’alimentation du bétail, tout en pouvant abriter une forte biodiversité. L'intensification des pratiques agricoles peut modifier les communautés de plantes et de pollinisateurs et leurs interactions plantes-pollinisateurs. Actuellement, les mécanismes expliquant ces changements sont peu étudiés, encore moins avec une approche utilisant les traits fonctionnels comme celle que nous proposons dans cette thèse. Les objectifs de cette thèse sont : 1) d’étudier l’effet de l’intensification agricole locale sur la diversité fonctionnelle des traits floraux et les conséquences sur la fonction de pollinisation ; 2) d’étudier les relations entre diversité des traits floraux et diversités taxonomique et fonctionnelle des pollinisateurs ; 3) de déterminer si la pilosité et la surface de la face des pollinisateurs sont des bons prédicteurs de la quantité de pollen transporté. Afin d’atteindre ces objectifs, nous avons sélectionné en Moselle 16 prairies permanentes appartenant à un gradient d’intensification agricole. Nous avons mesuré cinq traits floraux appartenant à trois catégories (signal, barrière à l’exploitation, récompense) sur les espèces de plantes de nos communautés. Nous avons constitué des réseaux visuels d’interactions plantes-pollinisateurs en capturant les insectes butineurs le long de transects. Enfin, nous avons mesuré la masse de ces insectes ainsi que la surface et la pilosité de leur face que nous avons relié à la quantité de pollen qu’ils transportaient. Tout d’abord, nous avons montré que la fertilité du sol a une influence significative sur la diversité fonctionnelle des traits floraux mais pas l’intensification agricole. Alors que la fertilité du sol est connue pour influencer la diversité fonctionnelle des traits végétatifs, ces résultats sont les premiers à montrer un effet du sol sur la diversité fonctionnelle des traits floraux, et pourraient avoir comme origine un phénomène d’exclusion compétitive. L’augmentation de la diversité fonctionnelle des traits floraux augmente significativement la fréquence des interactions plantes-pollinisateurs, proxy de la fonction de pollinisation. Ces résultats sont en concordance avec les relations positives attendues entre biodiversité et fonctionnement des écosystèmes. L’augmentation de la diversité fonctionnelle de la production de sucre augmente significativement la richesse taxonomique des pollinisateurs mais pas la diversité fonctionnelle de leur masse corporelle, suggérant l’importance de maximiser la diversité fonctionnelle de la production de sucre pour maintenir une forte diversité taxonomique de pollinisateurs à l’heure où cette dernière connaît un déclin. Enfin, nous avons montré que la quantité de pollen transporté sur la face des pollinisateurs augmente significativement avec la surface et la pilosité de cette partie de leur corps. Ce résultat est une validation de ces deux traits d’effet pour la pollinisation à un ensemble d’espèces de plantes sauvages, là où ils n’étaient partiellement validés que pour quelques espèces de plantes cultivées. Cette thèse apporte donc une perspective unique sur les effets en cascade des facteurs locaux jusqu’à la fonction de pollinisation en prairie permanente
Decline in biodiversity and its impacts on ecosystem functioning are critical issues we are facing in the 21st century. Intensive agriculture is nowadays considered as one of the factors behind this decline, sparking off a societal desire toward an agroecological transition. Agroecology aims at integrating ecological functions into food production processes. Permanent grasslands are at the core of these issues, because of their essential roles in livestock feeding, but also because of their ability to harbor a rich biodiversity. Intensification of agricultural practices can modify plant and pollinator communities, but also interactions between these two trophic levels. Presently, the mechanisms behind these modifications are little studied, and even less with a functional trait-based approach as we propose in this PhD thesis. The goals of this PhD thesis are: 1) to study the effects of local land-use intensification on functional diversity of floral traits and their consequences on pollination function; 2) to study the relationships between functional diversity of floral traits and both taxonomic and functional diversities of pollinators; 3) to determine if hairiness and surface of pollinator face are good predictors of face pollen load. To do so, we selected 16 permanent grasslands belonging to a land-use intensification gradient in Moselle, France. We measured five floral traits belonging to three categories (cue/signal, exploitation barrier, reward) from plant species in the communities we followed. We established visual plant-pollinator interaction networks by catching foraging insects along transects. Finally, we measured insect body mass, as well as the surface and the hairiness of their face which were related to their face pollen load. Firstly, we found a significant effect of soil fertility on functional diversity of floral traits, but no effect of land-use intensification. While soil fertility is already known to influence functional diversity of vegetative traits, our results show for the first time an effect of soil characteristics on functional diversity of floral traits, that could be caused by exclusive competition. Moreover, an increase in functional diversity of floral traits results in an increase in plant-pollinator interaction frequency, a proxy of pollination function. This result is in congruence with the expected positive relationships between biodiversity and ecosystem functioning. We also found that an increase in functional diversity of nectar sugar production increases pollinator taxonomic richness but not functional diversity of their body mass. This result suggests the importance to maximize functional diversity of sugar production to maintain a high taxonomic diversity of pollinators, while pollinators face currently a global decline. Lastly, we showed an increase in face pollen load of pollinators with hairiness as well as surface of this body part, validating these two pollination effect traits for a set of wild plant species, while until now it was only done for a few cultivated plant species. This PhD thesis thus brings a unique perspective of cascading effects from local factors to pollination function in permanent grasslands

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North, Amy D. "Investigation of observer variability using a new method for determining color matching functions /". Online version of thesis, 1991. http://hdl.handle.net/1850/11099.

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Mahajan, Rutvij Sanjay. "Empirical Analysis of Algorithms for the k-Server and Online Bipartite Matching Problems". Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/96725.

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The k–server problem is of significant importance to the theoretical computer science and the operations research community. In this problem, we are given k servers, their initial locations and a sequence of n requests that arrive one at a time. All these locations are points from some metric space and the cost of serving a request is given by the distance between the location of the request and the current location of the server selected to process the request. We must immediately process the request by moving a server to the request location. The objective in this problem is to minimize the total distance traveled by the servers to process all the requests. In this thesis, we present an empirical analysis of a new online algorithm for k-server problem. This algorithm maintains two solutions, online solution, and an approximately optimal offline solution. When a request arrives we update the offline solution and use this update to inform the online assignment. This algorithm is motivated by the Robust-Matching Algorithm [RMAlgorithm, Raghvendra, APPROX 2016] for the closely related online bipartite matching problem. We then give a comprehensive experimental analysis of this algorithm and also provide a graphical user interface which can be used to visualize execution instances of the algorithm. We also consider these problems under stochastic setting and implement a lookahead strategy on top of the new online algorithm.
MS

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Saunders, Paige F. "Targeting Functions: A New Approach to Anti-Smoking PSAs". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1308241861.

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Leipnitz, Marcos Tomazzoli. "Resilient regular expression matching on FPGAs with fast error repair". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/168788.

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O paradigma Network Function Virtualization (NFV) promete tornar as redes de computadores mais escaláveis e flexíveis, através do desacoplamento das funções de rede de hardware dedicado e fornecedor específico. No entanto, funções de rede computacionalmente intensivas podem ser difíceis de virtualizar sem degradação de desempenho. Neste contexto, Field-Programmable Gate Arrays (FPGAs) têm se mostrado uma boa opção para aceleração por hardware de funções de rede virtuais que requerem alta vazão, sem se desviar do conceito de uma infraestrutura NFV que visa alta flexibilidade. A avaliação de expressões regulares é um mecanismo importante e computacionalmente intensivo, usado para realizar Deep Packet Inpection, que pode ser acelerado por FPGA para atender aos requisitos de desempenho. Esta solução, no entanto, apresenta novos desafios em relação aos requisitos de confiabilidade. Particularmente para FPGAs baseados em SRAM, soft errors na memória de configuração são uma ameaça de confiabilidade significativa. Neste trabalho, apresentamos um mecanismo de tolerância a falhas abrangente para lidar com falhas de configuração na funcionalidade de módulos de avaliação de expressões regulares baseados em FPGA. Além disso, é introduzido um mecanismo de correção de erros que considera o posicionamento desses módulos no FPGA para reduzir o tempo de reparo do sistema, melhorando a confiabilidade e a disponibilidade. Os resultados experimentais mostram que a taxa de falha geral e o tempo de reparo do sistema podem ser reduzidos em 95% e 90%, respectivamente, com custos de área e performance admissíveis.
The Network Function Virtualization (NFV) paradigm promises to make computer networks more scalable and flexible by decoupling the network functions (NFs) from dedicated and vendor-specific hardware. However, network and compute intensive NFs may be difficult to virtualize without performance degradation. In this context, Field-Programmable Gate Arrays (FPGAs) have been shown to be a good option for hardware acceleration of virtual NFs that require high throughput, without deviating from the concept of an NFV infrastructure which aims at high flexibility. Regular expression matching is an important and compute intensive mechanism used to perform Deep Packet Inspection, which can be FPGA-accelerated to meet performance constraints. This solution, however, introduces new challenges regarding dependability requirements. Particularly for SRAM-based FPGAs, soft errors on the configuration memory are a significant dependability threat. In this work we present a comprehensive fault tolerance mechanism to deal with configuration faults on the functionality of FPGA-based regular expression matching engines. Moreover, a placement-aware scrubbing mechanism is introduced to reduce the system repair time, improving the system reliability and availability. Experimental results show that the overall failure rate and the system mean time to repair can be reduced in 95% and 90%, respectively, with manageable area and performance costs.

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Mohanty, Pragyan Paramita. "Function-based Algorithms for Biological Sequences". OpenSIUC, 2015. https://opensiuc.lib.siu.edu/dissertations/1120.

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AN ABSTRACT OF THE DISSERTATION OF PRAGYAN P. MOHANTY, for the Doctor of Philosophy degree in ELECTRICAL AND COMPUTER ENGINEERING, presented on June 11, 2015, at Southern Illinois University Carbondale. TITLE: FUNCTION-BASED ALGORITHMS FOR BIOLOGICAL SEQUENCES MAJOR PROFESSOR: Dr. Spyros Tragoudas Two problems at two different abstraction levels of computational biology are studied. At the molecular level, efficient pattern matching algorithms in DNA sequences are presented. For gene order data, an efficient data structure is presented capable of storing all gene re-orderings in a systematic manner. A common characteristic of presented methods is the use of binary decision diagrams that store and manipulate binary functions. Searching for a particular pattern in a very large DNA database, is a fundamental and essential component in computational biology. In the biological world, pattern matching is required for finding repeats in a particular DNA sequence, finding motif and aligning sequences etc. Due to immense amount and continuous increase of biological data, the searching process requires very fast algorithms. This also requires encoding schemes for efficient storage of these search processes to operate on. Due to continuous progress in genome sequencing, genome rearrangements and construction of evolutionary genome graphs, which represent the relationships between genomes, become challenging tasks. Previous approaches are largely based on distance measure so that relationship between more phylogenetic species can be established with some specifically required rearrangement operations and hence within certain computational time. However because of the large volume of the available data, storage space and construction time for this evolutionary graph is still a problem. In addition, it is important to keep track of all possible rearrangement operations for a particular genome as biological processes are uncertain. This study presents a binary function-based tool set for efficient DNA sequence storage. A novel scalable method is also developed for fast offline pattern searches in large DNA sequences. This study also presents a method which efficiently stores all the gene sequences associated with all possible genome rearrangements such as transpositions and construct the evolutionary genome structure much faster for multiple species. The developed methods benefit from the use of Boolean functions; their compact storage using canonical data structure and the existence of built-in operators for these data structures. The time complexities depend on the size of the data structures used for storing the functions that represent the DNA sequences and/or gene sequences. It is shown that the presented approaches exhibit sub linear time complexity to the sequence size. The number of nodes present in the DNA data structure, string search time on these data structures, depths of the genome graph structure, and the time of the rearrangement operations are reported. Experiments on DNA sequences from the NCBI database are conducted for DNA sequence storage and search process. Experiments on large gene order data sets such as: human mitochondrial data and plant chloroplast data are conducted and depth of this structure was studied for evolutionary processes on gene sequences. The results show that the developed approaches are scalable.

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Rajendran, Venkatprabhu. "Recognizing Table Formatting From Text Files". Miami University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=miami1165610803.

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Ng, Chi-Wing. "Behavioral and neural correlates of auditory encoding and memory functions in Rhesus Macaques". Diss., University of Iowa, 2011. https://ir.uiowa.edu/etd/1041.

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Auditory recognition memory in non-human primates is not well understood. Monkeys have difficulty acquiring auditory memory tasks, and limited capability maintaining auditory information over memory delays, relative to studies of visual memory. Neural substrates of auditory discrimination and recognition memory depend on superior temporal gyrus (STG), instead of rhinal cortex necessary for visual memory (Fritz et al., 2005). The current project assessed behavioral and neural correlates of auditory processing and memory function in monkeys, particularly focusing on the dorsal temporal pole (dTP), the rostral portion of STG. Chapter 2 examined recognition memory of monkeys under influences of various sound types. In a delayed matching-to-sample (DMTS) task, rhesus monkeys were trained to determine if two sounds, separated by a 5-second delay, were same (match trials) or different (nonmatch trials). Results demonstrated monkey vocalizations served as better cues than other sound types for auditory memory performance. Memory improvements may be due to familiarity and biological significance of con-specific sounds, analogous to using facial stimuli during visual tasks. Chapter 3 examined neuronal activity of dTP, when two monkeys performed an auditory DTMS task and listened to sound stimuli. Population encoding of sample stimuli in dTP was closely associated with memory accuracy. Moreover, a suppression effect on identical sounds was present, similar to processing in the ventral visual processing stream, inferior temporal cortex (ITC) and ventral temporal pole (vTP). Delay-related activity of dTP was weak, limited and short-lived, in contrast to visual studies reporting sustained activity over memory delays in ITC, vTP and prefrontal cortex. The findings provide preliminary evidence on why monkeys show limited memory capability, compared to visual memory, for auditory information. Neurons of dTP were sound-selective, and mainly evoked by one to four discrete stimuli only. Sound types and simple acoustic properties of sound stimuli cannot completely account for response profiles of dTP neurons. The findings suggest dTP is a higher order auditory area, and receives information from various auditory areas along STG. Dorsal temporal pole fits into proposals of neural networks for auditory processing, in which a hierarchical organization of information flow exists within the primate auditory nervous system.

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Groß, Anika. "Evolution von ontologiebasierten Mappings in den Lebenswissenschaften". Doctoral thesis, Universitätsbibliothek Leipzig, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-136766.

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Im Bereich der Lebenswissenschaften steht eine große und wachsende Menge heterogener Datenquellen zur Verfügung, welche häufig in quellübergreifenden Analysen und Auswertungen miteinander kombiniert werden. Um eine einheitliche und strukturierte Erfassung von Wissen sowie einen formalen Austausch zwischen verschiedenen Applikationen zu erleichtern, kommen Ontologien und andere strukturierte Vokabulare zum Einsatz. Sie finden Anwendung in verschiedenen Domänen wie der Molekularbiologie oder Chemie und dienen zumeist der Annotation realer Objekte wie z.B. Gene oder Literaturquellen. Unterschiedliche Ontologien enthalten jedoch teilweise überlappendes Wissen, so dass die Bestimmung einer Abbildung (Ontologiemapping) zwischen ihnen notwendig ist. Oft ist eine manuelle Mappingerstellung zwischen großen Ontologien kaum möglich, weshalb typischerweise automatische Verfahren zu deren Abgleich (Matching) eingesetzt werden. Aufgrund neuer Forschungserkenntnisse und Nutzeranforderungen verändern sich die Ontologien kontinuierlich weiter. Die Evolution der Ontologien hat wiederum Auswirkungen auf abhängige Daten wie beispielsweise Annotations- und Ontologiemappings, welche entsprechend aktualisiert werden müssen. Im Rahmen dieser Arbeit werden neue Methoden und Algorithmen zum Umgang mit der Evolution ontologie-basierter Mappings entwickelt. Dabei wird die generische Infrastruktur GOMMA zur Verwaltung und Analyse der Evolution von Ontologien und Mappings genutzt und erweitert. Zunächst wurde eine vergleichende Analyse der Evolution von Ontologiemappings für drei Subdomänen der Lebenswissenschaften durchgeführt. Ontologien sowie Mappings unterliegen teilweise starken Änderungen, wobei die Evolutionsintensität von der untersuchten Domäne abhängt. Insgesamt zeigt sich ein deutlicher Einfluss von Ontologieänderungen auf Ontologiemappings. Dementsprechend können bestehende Mappings infolge der Weiterentwicklung von Ontologien ungültig werden, so dass sie auf aktuelle Ontologieversionen migriert werden müssen. Dabei sollte eine aufwendige Neubestimmung der Mappings vermieden werden. In dieser Arbeit werden zwei generische Algorithmen zur (semi-) automatischen Adaptierung von Ontologiemappings eingeführt. Ein Ansatz basiert auf der Komposition von Ontologiemappings, wohingegen der andere Ansatz eine individuelle Behandlung von Ontologieänderungen zur Adaptierung der Mappings erlaubt. Beide Verfahren ermöglichen die Wiederverwendung unbeeinflusster, bereits bestätigter Mappingteile und adaptieren nur die von Änderungen betroffenen Bereiche der Mappings. Eine Evaluierung für sehr große, biomedizinische Ontologien und Mappings zeigt, dass beide Verfahren qualitativ hochwertige Ergebnisse produzieren. Ähnlich zu Ontologiemappings werden auch ontologiebasierte Annotationsmappings durch Ontologieänderungen beeinflusst. Die Arbeit stellt einen generischen Ansatz zur Bewertung der Qualität von Annotationsmappings auf Basis ihrer Evolution vor. Verschiedene Qualitätsmaße erlauben die Identifikation glaubwürdiger Annotationen beispielsweise anhand ihrer Stabilität oder Herkunftsinformationen. Eine umfassende Analyse großer Annotationsdatenquellen zeigt zahlreiche Instabilitäten z.B. aufgrund temporärer Annotationslöschungen. Dementsprechend stellt sich die Frage, inwieweit die Datenevolution zu einer Veränderung von abhängigen Analyseergebnissen führen kann. Dazu werden die Auswirkungen der Ontologie- und Annotationsevolution auf sogenannte funktionale Analysen großer biologischer Datensätze untersucht. Eine Evaluierung anhand verschiedener Stabilitätsmaße erlaubt die Bewertung der Änderungsintensität der Ergebnisse und gibt Aufschluss, inwieweit Nutzer mit einer signifikanten Veränderung ihrer Ergebnisse rechnen müssen. Darüber hinaus wird GOMMA um effiziente Verfahren für das Matching sehr großer Ontologien erweitert. Diese werden u.a. für den Abgleich neuer Konzepte während der Adaptierung von Ontologiemappings benötigt. Viele der existierenden Match-Systeme skalieren nicht für das Matching besonders großer Ontologien wie sie im Bereich der Lebenswissenschaften auftreten. Ein effizienter, kompositionsbasierter Ansatz gleicht Ontologien indirekt ab, indem existierende Mappings zu Mediatorontologien wiederverwendet und miteinander kombiniert werden. Mediatorontologien enthalten wertvolles Hintergrundwissen, so dass sich die Mappingqualität im Vergleich zu einem direkten Matching verbessern kann. Zudem werden generelle Strategien für das parallele Ontologie-Matching unter Verwendung mehrerer Rechenknoten vorgestellt. Eine größenbasierte Partitionierung der Eingabeontologien verspricht eine gute Lastbalancierung und Skalierbarkeit, da kleinere Teilaufgaben des Matchings parallel verarbeitet werden können. Die Evaluierung im Rahmen der Ontology Alignment Evaluation Initiative (OAEI) vergleicht GOMMA und andere Systeme für das Matching von Ontologien in verschiedenen Domänen. GOMMA kann u.a. durch Anwendung des parallelen und kompositionsbasierten Matchings sehr gute Ergebnisse bezüglich der Effektivität und Effizienz des Matchings, insbesondere für Ontologien aus dem Bereich der Lebenswissenschaften, erreichen
In the life sciences, there is an increasing number of heterogeneous data sources that need to be integrated and combined in comprehensive analysis tasks. Often ontologies and other structured vocabularies are used to provide a formal representation of knowledge and to facilitate data exchange between different applications. Ontologies are used in different domains like molecular biology or chemistry. One of their most important applications is the annotation of real-world objects like genes or publications. Since different ontologies can contain overlapping knowledge it is necessary to determine mappings between them (ontology mappings). A manual mapping creation can be very time-consuming or even infeasible such that (semi-) automatic ontology matching methods are typically applied. Ontologies are not static but underlie continuous modifications due to new research insights and changing user requirements. The evolution of ontologies can have impact on dependent data like annotation or ontology mappings. This thesis presents novel methods and algorithms to deal with the evolution of ontology-based mappings. Thereby the generic infrastructure GOMMA is used and extended to manage and analyze the evolution of ontologies and mappings. First, a comparative evolution analysis for ontologies and mappings from three life science domains shows heavy changes in ontologies and mappings as well as an impact of ontology changes on the mappings. Hence, existing ontology mappings can become invalid and need to be migrated to current ontology versions. Thereby an expensive redetermination of the mappings should be avoided. This thesis introduces two generic algorithms to (semi-) automatically adapt ontology mappings: (1) a composition-based adaptation relies on the principle of mapping composition, and (2) a diff-based adaptation algorithm allows for individually handling change operations to update mappings. Both approaches reuse unaffected mapping parts, and adapt only affected parts of the mappings. An evaluation for very large biomedical ontologies and mappings shows that both approaches produce ontology mappings of high quality. Similarly, ontology changes may also affect ontology-based annotation mappings. The thesis introduces a generic evaluation approach to assess the quality of annotation mappings based on their evolution. Different quality measures allow for the identification of reliable annotations, e.g., based on their stability or provenance information. A comprehensive analysis of large annotation data sources shows numerous instabilities, e.g., due to the temporary absence of annotations. Such modifications may influence results of dependent applications such as functional enrichment analyses that describe experimental data in terms of ontological groupings. The question arises to what degree ontology and annotation changes may affect such analyses. Based on different stability measures the evaluation assesses change intensities of application results and gives insights whether users need to expect significant changes of their analysis results. Moreover, GOMMA is extended by large-scale ontology matching techniques. Such techniques are useful, a.o., to match new concepts during ontology mapping adaptation. Many existing match systems do not scale for aligning very large ontologies, e.g., from the life science domain. One efficient composition-based approach indirectly computes ontology mappings by reusing and combining existing mappings to intermediate ontologies. Intermediate ontologies can contain useful background knowledge such that the mapping quality can be improved compared to a direct match approach. Moreover, the thesis introduces general strategies for matching ontologies in parallel using several computing nodes. A size-based partitioning of the input ontologies enables good load balancing and scalability since smaller match tasks can be processed in parallel. The evaluation of the Ontology Alignment Evaluation Initiative (OAEI) compares GOMMA and other systems in terms of matching ontologies from different domains. Using the parallel and composition-based matching, GOMMA can achieve very good results w.r.t. efficiency and effectiveness, especially for ontologies from the life science domain

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Finical, Stephanie. "Duration of a sung token in pitch matching as a function of the duration of the response". Connect to resource, 2007. http://hdl.handle.net/1811/25253.

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Thesis (Honors)--Ohio State University, 2007.
Title from first page of PDF file. Document formatted into pages: contains iv, 18 p.; also includes graphics. Includes bibliographical references (p. 18). Available online via Ohio State University's Knowledge Bank.

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Hughet, James. "Binaural Hearing Effects of Mapping Microphone Array's Responses to a Listener's Head-Related Transfer Functions". Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/35361.

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This thesis focuses on the mapping of the microphone array’s response to match the characteristics of a human subject’s Head-Related Transfer Function (HRTF). The mapping of the response is first explored with a ‘monaural HRTF matching’ that filters the response independent of the arrival angles. For arbitrary array geometry with the listener external to the acoustic, the monaural HRTF matching did not provide listeners with enough spatial information to precisely localize sound sources. To correct this, a preprocessor control algorithm was added to the HRTF matching, a ‘binaural HRTF matching’ process. The binaural HRTF matching increased the listeners’ performance in perceiving the location of a sound source. With the addition of simulated head movement, the listeners’ perception increased by 20%. An issue with this approach is the use of HRTFs other than the listeners’ measured HRTF, creating a psychoacoustic based error in localization, i.e., front/back confusion.
Master of Science

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Parrish, Linda Titera. "The Effect of Age, Noise Level, and Frequency on Loudness Matching Functions of Normal Hearing Listeners with Noise Masking". BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5793.

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Loudness recruitment is an abnormally rapid growth of perceived loudness above the hearing threshold that slows to normal growth as the intensity of the signal increases. Recruitment is common in sensorineural hearing loss and in simulated hearing loss with noise masking. This study looked at possible differences in loudness recruitment with age, noise level, and frequency. Participants from two age groups were tested. Group A included participants aged 18 to 30 years and Group B included participants aged 50 to 75 years. Participants practiced the Alternate Binaural Loudness Balance (ABLB) test without noise present. They then repeated the tests with masking noise. Tests were completed with two different noise levels (50 dB SPL and 70 dB SPL), and two different test tone frequencies (1000 Hz and 2000 Hz). Participants identified loudness matching points to reference intensities of 20, 40, 60, and 80 dB HL. Participants completed 3 trials at each intensity level. Difference scores of the intensity of the loudness matching point minus the intensity of the reference tone were computed and analyzed statistically. An analysis of variance (ANOVA) for repeated measures fails to show significance for between-subjects effect for age, within subject effect for frequency, and trial. An ANOVA for repeated measures shows significant within subject effect for noise and for intensity. The 70 dB SPL noise level shows greater difference scores and a steeper loudness matching function slope than the 50 dB SPL noise level. The greater difference scores and steeper slope are expected due to the higher hearing threshold created with the higher noise level. As the intensity level increases, the difference score decreases. The decrease in difference scores with increasing intensity levels shows the presence of loudness recruitment. The results of this study suggest the use of masking noise in order to measure recruitment is an acceptable simulation. Age alone does not account for changes in loudness recruitment. Therefore, recruitment measurement with noise masking may be a potential marker of early auditory dysfunction.

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Singh, Sachinkumar B. P. "Assessing the long-term clinical effectiveness of inhaled and anti-inflammatory therapies for lung disease in cystic fibrosis". Diss., University of Iowa, 2014. https://ir.uiowa.edu/etd/6502.

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Cystic fibrosis (CF) is the most common life-restricting, genetically inherited disease among Caucasians affecting approximately 30,000 people in the United States. Lung disease is the major cause of morbidity and mortality in CF. A number of oral, inhaled, and intravenous therapies are available to combat CF lung disease. Of these, this research project focused on inhaled dornase alfa, oral azithromycin, inhaled tobramycin, and inhaled aztreonam. Data to address three research aims were requested and obtained from the Cystic Fibrosis Foundation Patient Registry (CFFPR). The first aim examined the use of inhaled dornase alfa in younger children with CF. With no clinical efficacy data of dornase alfa in children ≤ 6 years of age, the study utilized subsequent forced expiratory volume in 1 second (FEV₁) measured between 6 - 7 years of age, to assess the effectiveness of long-term dornase alfa use ≤ 6 years of age. Propensity score methods were used to reduce the likelihood of treatment indication bias. The results suggested that receiving treatment with dornase alfa before 6 years of age did not improve FEV₁ between 6 - 7 years. Unmeasured covariates leading to treatment indication bias were likely one of the key explanations for these results. Additionally, lack of a more sensitive outcome than FEV₁ to assess lung function in young patients with early lung damage was thought to be another reason for the failure to reject the null hypothesis. The second aim assessed the long-term clinical effectiveness of chronic azithromycin use on the rate of FEV₁ decline in CF patients between 6 - 20 years of age. This study was novel in that the rate of FEV₁ decline, rather than change in FEV₁ from baseline, was the primary outcome, which was characterized using propensity score matching followed by a linear mixed model analysis. The results of the analysis suggested that the rate of FEV₁ decline was slower in patients who did not receive chronic treatment with azithromycin. Treatment indication bias was thought to play an important role in the direction of the association between treatment and outcome. Associations between FEV₁ % predicted and many of the other study variables included in the analysis were consistent with previous studies. The final aim compared the clinical effectiveness of a combination of inhaled tobramycin and aztreonam with inhaled tobramycin alone on the rate of FEV₁ decline in CF patients between 6 - 20 years of age. This aim was novel in that the effect of this combination treatment on rate of decline in FEV₁ has never been assessed. A linear mixed model analysis was used after matching patients in the two treatment groups on their propensity scores. Once again, the results were contrary to the alternative hypothesis with the combination group having a steeper rate of FEV₁ decline than the group that was treated with tobramycin alone. An important reason for this result was thought to be unresolved treatment indication bias that could not be eliminated even with the use of the propensity score methods used to test the associated hypothesis. The use of validated methods of analysis, i.e., propensity scores, to counter treatment indication bias using the largest available observational dataset for CF, was one of the key strengths of this study. Moreover, this study highlighted important weaknesses in the CFFPR with regards to lack of data on patient and physician-level variables - an area of active interest for the Cystic Fibrosis Foundation.

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Berry, Meredith Steele. "Reinforcer Magnitude and Resistance to Change of Forgetting Functions and Response Rates". DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1269.

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The present experiment was conducted to investigate the effects of reinforcer magnitude on resistance to disruption of remembering and response rates. Pigeons were exposed to a variable-interval (VI), delayed-matching-to-sample procedure (DMTS) with two components (rich and lean). Specifically, completion of a VI 20 second (s) multiple schedule resulted in DMTS trials in both components. In a DMTS trial, a choice of one of two comparison stimuli (e.g., blue key) results in reinforcement if the choice matches some property of the sample stimulus presented previously. Sample and comparison stimuli are separated by a delay. Four delays (0.1, 4, 8, and 16 s) were used between the sample and comparison stimuli in the study. The difference between rich and lean components was the length of hopper duration following a correct response. The probability of reinforcement following a correct response in both components was .5. Each pigeon was exposed to 50 sessions of initial baseline and then 30 sessions of baseline between each disruptive condition (extinction, intercomponent interval [ICI] food, lighting the houselight during delays, and prefeeding). Separable aspects of the forgetting functions (initial discriminability and rate of forgetting) were examined by determining accuracy at each delay. During baseline, response rates were higher in the rich component relative to the lean. Accuracy decreased as delay increased in both rich and lean components, and accuracy was consistently higher in the rich relative to the lean component. During disruptive conditions, extinction, ICI food, and prefeeding disrupted response rates, but lighting the houselight during the delays had little effect. During the DMTS portion of the procedure, extinction and prefeeding decreased initial discriminability and lighting the houselight during the delay increased rate of forgetting. Intercomponent food had little effect on accuracy. Accuracy in the rich component was more resistant to disruption relative to the lean component during extinction. These results indicate that certain disruptors do not have the same disruptive effect across response rates and accuracy (e.g., ICI food). These data also suggest that when systematic differences in accuracy between rich and lean components are revealed, performance in the rich component tends to be more resistant to disruption.

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Yaveroglu, Omer Nebil. "Identification Of Functionally Orthologous Protein Groups In Different Species Based On Protein Network Alignment". Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612395/index.pdf.

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In this study, an algorithm named ClustOrth is proposed for determining and matching functionally orthologous protein clusters in different species. The algorithm requires protein interaction networks of the organisms to be compared and GO terms of the proteins in these interaction networks as prior information. After determining the functionally related protein groups using the Repeated Random Walks algorithm, the method maps the identified protein groups according to the similarity metric defined. In order to evaluate the similarities of protein groups, graph theoretical information is used together with the context information about the proteins. The clusters are aligned using GO-Term-based protein similarity measures defined in previous studies. These alignments are used to evaluate cluster similarities by defining a cluster similarity metric from protein similarities. The top scoring cluster alignments are considered as orthologous. Several data sources providing orthology information have shown that the defined cluster similarity metric can be used to make inferences about the orthological relevance of protein groups. Comparison with a protein orthology prediction algorithm named ISORANK also showed that the ClustOrth algorithm is successful in determining orthologies between proteins. However, the cluster similarity metric is too strict and many cluster matches are not able to produce high scores for this metric. For this reason, the number of predictions performed is low. This problem can be overcomed with the introduction of different sources of information related to proteins in the clusters for the evaluation of the clusters. The ClustOrth algorithm also outperformed the NetworkBLAST algorithm which aims to find orthologous protein clusters using protein sequence information directly for determining orthologies. It can be concluded that this study is one of the leading studies addressing the protein cluster matching problem for identifying orthologous functional modules of protein interaction networks computationally.

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Dong, Yingying. "Microeconometric Models with Endogeneity -- Theoretical and Empirical Studies". Thesis, Boston College, 2009. http://hdl.handle.net/2345/753.

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Thesis advisor: Arthur Lewbel
This dissertation consists of three independent essays in applied microeconomics and econometrics. Essay 1 investigates the issue why individuals with health insurance use more health care. One obvious reason is that health care is cheaper for the insured. But additionally, having insurance can encourage unhealthy behavior via moral hazard. The effect of health insurance on medical utilization has been extensively studied; however, previous work has mostly ignored the effect of insurance on behavior and how that in turn affects medical utilization. This essay examines these distinct effects. The increased medical utilization due to reduced prices may help the insured maintain good health, while that due to increased unhealthy behavior does not, so distinguishing these two effects has important policy implications. A two-period dynamic forward-looking model is constructed to derive the structural causal relationships among the decision to buy insurance, health behaviors (drinking, smoking, and exercise), and medical utilization. The model shows how exogenous changes in insurance prices and past behaviors can identify the direct and indirect effects of insurance on medical utilization. An empirical analysis also distinguishes between intensive and extensive margins (e.g., changes in the number of drinkers vs. the amount of alcohol consumed) of the insurance effect, which turns out to be empirically important. Health insurance is found to encourage less healthy behavior, particularly heavy drinking, but this does not yield a short term perceptible increase in doctor or hospital visits. The effects of health insurance are primarily found at the intensive margin, e.g., health insurance may not cause a non-drinker to take up drinking, while it encourages a heavy drinker to drink even more. These results suggest that to counteract behavioral moral hazard, health insurance should be coupled with incentives that target individuals who currently engage in unhealthy behaviors, such as heavy drinkers. Essay 2 examines the effect of repeating kindergarten on the retained children's academic performance. Although most existing research concludes that grade retention generates no benefits for retainees' later academic performance, holding low achieving children back has been a popular practice for decades. Drawing on a recently collected nationally representative data set in the US, this paper estimates the causal effect of kindergarten retention on the retained children's later academic performance. Since children are observed being held back only when they enroll in schools that permit retention, this paper jointly models 1) the decision of entering a school allowing for kindergarten retention, 2) the decision of undergoing a retention treatment in kindergarten, and 3) children's academic performance in higher grades. The retention treatment is modeled as a binary choice with sample selection. The outcome equations are linear regressions including the kindergarten retention dummy as an endogenous regressor with a correlated random coefficient. A control function estimator is developed for estimating the resulting double-hurdle treatment model, which allows for unobserved heterogeneity in the retention effect. As a comparison, a nonparametric bias-corrected nearest neighbor matching estimator is also implemented. Holding children back in kindergarten is found to have positive but diminishing effects on their academic performance up to the third grade. Essay 3 proves the semiparametric identification of a binary choice model having an endogenous regressor without relying on outside instruments. A simple estimator and a test for endogeneity are provided based on this identification. These results are applied to analyze working age male's migration within the US, where labor income is potentially endogenous. Identification relies on the fact that the migration probability among workers is close to linear in age while labor income is nonlinear in age(when both are nonparametrically estimated). Using data from the PSID, this study finds that labor income is endogenous and that ignoring this endogeneity leads to downward bias in the estimated effect of labor income on the migration probability
Thesis (PhD) — Boston College, 2009
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Economics

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Azevedo, Alana katielle Nogueira. "Risco moral em seguro saude: Uma anÃlise para os Estados do nordeste utilizado estimadores de Matching por propensity score". Universidade Federal do CearÃ, 2008. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=2603.

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Universidade Federal do CearÃ
Esta dissertaÃÃo analisa a existÃncia de risco moral no sistema de saÃde brasileiro a partir de uma anÃlise de estimaÃÃo de dois modelos de matching baseado no propensityscore, um a partir de estratificaÃÃo e outro a partir de uma funÃÃo kernel. A variÃvel de utilizaÃÃo do serviÃo mÃdicoselecionada foi a de consultas mÃdicas e a anÃlise compreendeu os nove estados do Nordeste doBrasil. Osresultados indicam presenÃa de risco moral tanto pela estimaÃÃo a partir de estratoscomo a partir de uma funÃÃo kernel. Para o modelo de estratificaÃÃo o valor estimado da diferenÃa de procura por consultas mÃdicas ficou entre 1,014 e 2,262 vezes, com o estado do RioGrande do Norte apresentando a maior diferenÃa. JÃ para o modelo a partir de uma funÃÃo kernel,o valor estimado da diferenÃa de procura por consultas mÃdicas ficou entre 0,866 e 2,242 vezes,com o estado do MaranhÃo apresentando a menor diferenÃa. Ouseja, indivÃduos que possuemplanos de saÃde geralmente buscam maior atendimento mÃdico do que caso nÃo estivessem cobertos por nenhum plano.
This dissertation analised the existence of moral hazard in the brazilian health system using anestimation of two propensity score matching models, one by stratification and the other one usinga kernel function. The variable of healthcare utilization selected was the medical visits and theanalysis was made considering the nine states of Northeast of Brazil. The results indicatedexistence of moral hazard for both stratification and kernel function estimation. For thestratification model the stimated value of the diference in medical visits stayed between 1,014 e 2,262 times, the state of Rio Grande do Norte had the greater diference. For the kernel functionmodel the stimated value of the diference in medical visits stayed between 0,866 e 2,242 times,the state of MaranhÃo had the smallest diference. So, individuals with health insurance use morethe healthcare than if they only have access to public services.

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Moradi, Arvin. "Smart Clustering System for Filtering and Cleaning User Generated Content : Creating a profanity filter for Truecaller". Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-124408.

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This thesis focuses on investigating and creating an application for filtering user-generated content. The method was to examine how profanity and racist expressions are used and manipulated to evade filtering processes in similar systems. Focus also went on to study different algorithms to get this process to be quick and efficient, i.e., to process as many names in the shortest amount of time possible. This is because the client needs to filter millions of new uploads every day. The result shows that the application detects profanity and manipulated profanity. Data from the customer’s database was also used for testing purposes, and the result showed that the application also works in practice. The performance test shows that the application has a fast execution time. We could see this by approximating it to a linear func-tion with respect to time and the number of names entered. The conclusion was that the filter works and discovers profanity not detected earlier. Future updates to strengthen the decision process could be to introduce a third-party service, or a web interface where you can manually control decisions. Execution time is good and shows that 10 million names can be pro-cessed in about 6 hours. In the future, one can parallelize queries to the database so that multiple names can be processed simultaneously.
Denna avhandling fokuserar på att utreda och skapa en applikation för filtrering av användargenererat innehåll. Metoden gick ut på att undersöka hur svordomar samt rasistiska uttryck används och manipuleras för att undgå filtrerings processer i liknande system. Fokus gick även ut på att studera olika algoritmer för att få denna process att vara snabb och effektiv, dvs kunna bearbeta så många namn på kortast möjliga tid. Detta beror på att kunden i detta sammanhang får in miljontals nya uppladdningar varje dag, som måste filtreras innan använding. Resultatet visar att applikationen upptäcker svordomar i olika former. Data från kundens databas användes också för test syfte, och resultatet visade att applikationen även fungerar i praktiken. Prestanda testet visar att applikationen har en snabb exekveringstid. Detta kunde vi se genom att estimera den till en linjär funktion med hänsyn till tid och antal namn som matats in. Slutsatsen blev att filtret fungerar och upptäcker svordomar som inte upptäckts tidigare i kundens databas. För att stärka besluten i processen kan man i framtida uppdateringar införa tredje parts tjänster, eller ett web interface där man manuelt kan styra beslut. Exekverings tiden är bra och visar att 10 miljoner namn kan bearbetas på cirka 6 timmar. I framtiden kan man parallellisera förfrågningarna till databasen så att flera namn kan bearbetas samtidigt.

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Sand, Nelly. "The Beveridge Curve : A comparison between the three largest labour market regions in Sweden; Stockholm-, Västra Götaland- and Skåne county and the effect of the building of the Öresund Bridge on the labour market matching efficiency of Skåne county". Thesis, Linnéuniversitetet, Institutionen för nationalekonomi och statistik (NS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-105448.

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This paper investigates the relationship between vacant job positions and unemployed workers, illustrated by the Beveridge curve, a tool for observing the matching process and the condition of a labour market. The Swedish case is studied together with its three largest labour market regions, i.e., Stockholm-, Västra Götaland- and Skåne county. A comparison opens up a discussion of whether local labour markets with similar characteristics located in different parts of the country behave similarly or in what way they distinguish. Furthermore, these three regions are expected to influence the Swedish Beveridge curve to a larger extent, which is also examined in the paper. In addition, the effect of an exogenous shock, such as the building of the Öresund Bridge, expanding the labour market of Skåne county by connection to another metropolitan area, Copenhagen, is studied. This is done by comparing the matching efficiency before and after the bridge is opened. Moreover, the effect in Skåne is then analysed in accordance with the same period for the other regions included, to get an indication of whether the bridge alone provides a change in matching efficiency or if changes are connected to national events that influence all regions similarly. The analysis is based on monthly data from year 1996-2020, collected from the Swedish Public Employment service and Statistics Sweden, primarily. Graphical illustrations of the Beveridge curve in combination with OLS regressions provide concluding results that the Beveridge curves for the three regional labour markets observed are shaped rather similarly and experience shifts and movements during the same time points, generally. Skåne county is the exception and experience more horizontal and vertical movements compared to Stockholm- and Västra Götaland county and the Swedish average. Furthermore, there are statistically significant estimates ensuring the negative relationship between unemployment- and vacancy rate, i.e., a downward sloping Beveridge curve for all regions. Not enough evidence on the effect of the Öresund Bridge on the matching efficiency of Skåne county is provided to present a valid conclusion regarding this topic.

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Elamin, Obbey Ahmed. "Nonparametric kernel estimation methods for discrete conditional functions in econometrics". Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/nonparametric-kernel-estimation-methods-for-discrete-conditional-functions-in-econometrics(d443e56a-dfb8-4f23-bfbe-ec98ecac030b).html.

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This thesis studies the mixed data types kernel estimation framework for the models of discrete dependent variables, which are known as kernel discrete conditional functions. The conventional parametric multinomial logit MNL model is compared with the mixed data types kernel conditional density estimator in Chapter (2). A new kernel estimator for discrete time single state hazard models is developed in Chapter (3), and named as the discrete time “external kernel hazard” estimator. The discrete time (mixed) proportional hazard estimators are then compared with the discrete time external kernel hazard estimator empirically in Chapter (4). The work in Chapter (2) attempts to estimate a labour force participation decision model using a cross-section data from the UK labour force survey in 2007. The work in Chapter (4) estimates a hazard rate for job-vacancies in weeks, using data from Lancashire Careers Service (LCS) between the period from March 1988 to June 1992. The evidences from the vast literature regarding female labour force participation and the job-market random matching theory are used to examine the empirical results of the estimators. The parametric estimator are tighten by the restrictive assumption regarding the link function of the discrete dependent variable and the dummy variables of the discrete covariates. Adding interaction terms improves the performance of the parametric models but encounters other risks like generating multicollinearity problem, increasing the singularity of the data matrix and complicates the computation of the ML function. On the other hand, the mixed data types kernel estimation framework shows an outstanding performance compared with the conventional parametric estimation methods. The kernel functions that are used for the discrete variables, including the dependent variable, in the mixed data types estimation framework, have substantially improved the performance of the kernel estimators. The kernel framework uses very few assumptions about the functional form of the variables in the model, and relay on the right choice of the kernel functions in the estimator. The outcomes of the kernel conditional density shows that female education level and fertility have high impact on females propensity to work and be in the labour force. The kernel conditional density estimator captures more heterogeneity among the females in the sample than the MNL model due to the restrictive parametric assumptions in the later. The (mixed) proportional hazard framework, on the other hand, missed to capture the effect of the job-market tightness in the job-vacancies hazard rate and produce inconsistent results when the assumptions regarding the distribution of the unobserved heterogeneity are changed. The external kernel hazard estimator overcomes those problems and produce results that consistent with the job market random matching theory. The results in this thesis are useful for nonparametric estimation research in econometrics and in labour economics research.

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36

Cervetti, Matteo. "Pattern posets: enumerative, algebraic and algorithmic issues". Doctoral thesis, Università degli studi di Trento, 2003. http://hdl.handle.net/11572/311140.

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The study of patterns in combinatorial structures has grown up in the past few decades to one of the most active trends of research in combinatorics. Historically, the study of permutations which are constrained by not containing subsequences ordered in various prescribed ways has been motivated by the problem of sorting permutations with certain devices. However, the richness of this notion became especially evident from its plentiful appearances in several very different disciplines, such as pure mathematics, mathematical physics, computer science, biology, and many others. In the last decades, similar notions of patterns have been considered on discrete structures other than permutations, such as integer sequences, lattice paths, graphs, matchings and set partitions. In the first part of this talk I will introduce the general framework of pattern posets and some classical problems about patterns. In the second part of this talk I will present some enumerative results obtained in my PhD thesis about patterns in permutations, lattice paths and matchings. In particular I will describe a generating tree with a single label for permutations avoiding the vincular pattern 1 - 32 - 4, a finite automata approach to enumerate lattice excursions avoiding a single pattern and some results about matchings avoiding juxtapositions and liftings of patterns.

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Cervetti, Matteo. "Pattern posets: enumerative, algebraic and algorithmic issues". Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/311152.

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The study of patterns in combinatorial structures has grown up in the past few decades to one of the most active trends of research in combinatorics. Historically, the study of permutations which are constrained by not containing subsequences ordered in various prescribed ways has been motivated by the problem of sorting permutations with certain devices. However, the richness of this notion became especially evident from its plentiful appearances in several very different disciplines, such as pure mathematics, mathematical physics, computer science, biology, and many others. In the last decades, similar notions of patterns have been considered on discrete structures other than permutations, such as integer sequences, lattice paths, graphs, matchings and set partitions. In the first part of this talk I will introduce the general framework of pattern posets and some classical problems about patterns. In the second part of this talk I will present some enumerative results obtained in my PhD thesis about patterns in permutations, lattice paths and matchings. In particular I will describe a generating tree with a single label for permutations avoiding the vincular pattern 1 - 32 - 4, a finite automata approach to enumerate lattice excursions avoiding a single pattern and some results about matchings avoiding juxtapositions and liftings of patterns.

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38

Kim, Sunjin. "Essays on Network formation games". Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/104598.

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This dissertation focuses on studying various network formation games in Economics. We explore a different model in each chapter to capture various aspects of networks. Chapter 1provides an overview of this dissertation. Chapter 2 studies the possible Nash equilibrium configurations in a model of signed network formation as proposed by Hiller (2017). We specify the Nash equilibria in the case of heterogeneous agents. We find 3 possible Nash equilibrium configurations: Utopia network, positive assortative matching, and disassortative matching. We derive the specific conditions under which they arise in a Nash equilibrium. In Chapter 3, we study a generalized model of signed network formation game where the players can choose not only positive and negative links but also neutral links. We check whether the results of the signed network formation model in the literature still hold in our generalized framework using the notion of pairwise Nash equilibrium. Chapter 4 studies inequality in a weighted network formation model using the notion of Nash equilibrium. As a factor of inequality, there are two types of players: Rich players and poor players. We show that both rich and poor players designate other rich players as their best friends. As a result, We present that nested split graphs are drawn from survey data because researchers tend to ask respondents to list only a few friends.
Doctor of Philosophy
This dissertation focuses on studying various network formation games in Economics. We explore a different model in each chapter to capture various aspects of networks. Chapter 1 provides an overview of this dissertation. Chapter 2 studies the possible singed network configurations in equilibrium. In the signed network, players can choose a positive (+) relationship or a negative (-) relationship toward each other player. We study the case that the players are heterogeneous. We find 3 possible categories of networks in equilibrium: Utopia network, positive assortative matching, and disassortative matching. We derive the specific conditions under which they arise in equilibrium. In Chapter 3, we study a generalized model of signed network formation game where the players can choose not only positive and negative links but also neutral links. We check whether the results of the signed network formation model in the literature still hold in our generalized framework. Chapter 4 studies inequality in a weighted network formation model using the notion of Nash equilibrium. In this weighted network model, each player can choose the level of relationship. As a factor of inequality, there are two types of players: rich players and poor players. We show that both rich and poor players choose other rich players as their best friends. As a result, we present that nested split graphs are drawn from survey data because these social network data are censored due to the limit of the number of responses.

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39

Kovács, Martin. "Techniky reprezentace pro evoluční návrh celulárních automatů". Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2016. http://www.nusl.cz/ntk/nusl-255340.

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The aim of this thesis is to experimentally evaluate the performance of several distinct representations of transition functions for cellular automata. Cellular automata have many potential applications for simulating various phenomena (e.g. natural processes, physical systems, etc.). Parallel computation of cellular automata is based on local cell interactions. Such computation, however, may prove difficult to program the CA, which is the reason for applying evolutionary techniques for the design of cellular automata in many cases. Evolutionary algorithms, based on Darwin's theory of evolution, have been used to find human-competitive solutions to many problems. In order to perform the evolutionary design of cellular automata, special encodings of the candidate solutions are often necessary. For this purpose the performance testing of various representations of the transition functions will be investigated. In particular, table representation, conditionally matching rules, and genetic programming will be treated. The problem of square calculations in cellular automata will be considered as a case study.

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40

Parajuli, Avishek. "Predictive Lane Boundary-Detection in Roads with Non-Uniform Surface Illumination". Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1366632262.

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Becerra, Gustavo Gabriel. "Mitigação de incertezas atraves da integração com ajuste de historico de produção". [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263757.

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Orientadores: Denis Jose Schiozer, Celio Maschio
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica e Instituto de Geociencias
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Resumo: A escassez de informações de qualidade introduz risco ao processo de previsão da produção de petróleo tornando imprescindível o ajuste de histórico de produção, que é a calibração do modelo a partir da resposta produtiva registrada. O ajuste é um problema inverso, em que diferentes combinações dos valores dos parâmetros do reservatório podem conduzir a respostas aceitáveis, especialmente quando o grau de incerteza desses parâmetros é elevado. A integração do ajuste de histórico com a análise probabilística dos cenários representativos conduz à obtenção de uma metodologia para detecção dos modelos calibrados dentro de uma faixa de aceitaçãodefinida. O tratamento de atributos interdependentes de influência global e local e o avanço por etapas são necessários. Desta forma, o objetivo deste trabalho é apresentar uma metodologia que integra a análise de incertezas com o ajuste de histórico em modelos de reservatórios complexos. Este procedimento auxilia a detectar os atributos incertos críticos e sua possível variação com o intuito de estimar a faixa representativa das reservas a desenvolver. Não é alvo obter o melhor ajuste determinístico, mas refletir como o histórico possibilita uma mitigação das incertezas. Assim, a meta é usar modelos mais complexos e aprimorar a metodologia iniciada por Moura Filho (2006), desenvolvida para um modelo teórico simples. São utilizados dois casos de estudo de complexidade similar. Um deles referente ao reservatório do Campo de Namorado, utilizado para verificar e validar, em nível global, a aplicação da metodologia. Na etapa de aplicação, é usado um modelo sintético construído a partir de dados de afloramentos reais no Brasil e compreendendo informações de campos análogos com sistemas turbidíticos depositados em águas profundas. Os métodos aplicados, mediante a redefinição das probabilidades associadas e níveis dos atributos incertos, permitem: (1) reduzir a faixa de ajustes possíveis e obter modelos mais confiáveis; (2) identificar e condicionar à incerteza presente em função dos dados registrados; (3) diminuir os intervalos de incerteza dos parâmetros críticos identificados; (4) demarcar os limites seguros do desempenho futuro do reservatório. A conseqüência é um aumento da confiança no uso da simulação como ferramenta auxiliar do processo decisório. Além disso, procura-se fornecer à equipe multidisciplinar uma metodologia para reduzir o tempo empregado no gerenciamento de múltiplos atributos incertos na etapa de ajuste do modelo.
Abstract: The lack of reliable data or with high degree of uncertainty yields risk to the process of production prediction making the history matching, the model calibration from the registered field production indispensable. History matching is an inverse problem and, in general, different combinations of reservoir attributes can lead acceptable solutions, especially whit high degree of uncertainty of these attributes. The integration of history matching with a probabilistic analysis of representative models yields a way to detect matched models inside an acceptance interval, providing more efficient framework for predictions. It is necessary to consider dependences between global and local attributes. The scope of this work is to present a methodology that integrates the uncertainty analysis with the history matching process in complex models. This procedure helps to detect critical subsurface attributes and their possible variation, in order to estimate a representative range of the additional reserves to be developed. . It is not an objective to obtain the best deterministic model, but to mitigate uncertainties by using observed data. The objective is to improve the methodology initiated by Moura Filho (2006), applied to a simple model. The methodology presented in this work is applied in two study cases with similar complexity. Firstly, the methodology is verified and validated, on global scale, in Namorado Field. Then, at the application stage, it is chosen a synthetic reservoir model made from real outcrop data of Brazil and involving information from analog fields with turbiditic systems deposited in deep waters. The methodology allows the redefinition of the probability and levels of the dynamic and static attributes in order: (1) to reduce the group of possible history matching obtaining more realistic models; (2) to identify the existent uncertainty as a function of observed data; (3) to decrease the uncertainty range of critical reservoir parameters; (4) to increase the confidence in production forecast. One contribution of this work is to present a quantitative approach to increase the reliability on the use of reservoir simulation as an auxiliary tool in decision processes. Another purpose of this work is to provide a procedure to reduce the consumed time to handle multiples uncertainty attributes during the history matching.
Mestrado
Reservatórios e Gestão
Mestre em Ciências e Engenharia de Petróleo

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42

Michel, Jean-Luc. "Polysimplices in euclidean spaces and the enumeration of domino tilings of rectangles". Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209922.

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Nous étudions, dans la première partie de notre thèse, les polysimplexes d’un espace euclidien de dimension quelconque, c’est-à-dire les objets consistant en une juxtaposition de simplexes réguliers (de tétraèdres si la dimension est 3) accolés le long de leurs faces. Nous étudions principalement le groupe des symétries de ces polysimplexes. Nous présentons une façon de représenter un polysimplexe à l’aide d’un diagramme. Ceci fournit une classification complète des polysimplexes à similitude près. De plus, le groupe des symétries se déduit du groupe des automorphismes du diagramme. Il découle en particulier de notre étude qu’en dimension supérieure à 2, une telle structure ne possède jamais deux faces parallèles et ne contient jamais de circuit fermé de simplexes.

Dans la seconde partie de notre thèse, nous abordons un problème classique de combinatoire :l’énumération des pavages d’un rectangle mxn à l’aide de dominos. Klarner et Pollack ont montré qu’en fixant m la suite obtenue vérifie une relation de récurrence linéaire à coefficients constants. Nous établissons une nouvelle méthode nous permettant d’obtenir la fonction génératrice correspondante et la calculons pour m <= 16, alors qu’elle n’était connue que pour m <= 10.

Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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43

Wallin, Joakim. "Systematic planning and execution of ﬁnite element model updating". Licentiate thesis, KTH, Bro- och stålbyggnad, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-172295.

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In design of bridges and for estimation of dynamic properties and load carrying capacity Finite Element Method (FEM) is often used as a tool. The physical quantities used in the Finite Element (FE) model are often connected to varying degrees of uncertainty. To deal with these uncertainties conservative parameter estimates and safety factors are used. By calibrating the bridge FE model to better ﬁt with the response of the real structure, less conservative parameter values can be chosen. This method of comparing measured and response with estimates from a FE model and calibrating the model parameters is called Finite Element Model Updating (FEMU). In the present thesis diﬀerent aspects of FEMU are investigated. The ﬁrst part comprises a literature review covering all aspects of FEMU with special focus on the choice of updating parameters, objective functions for iterative updating procedures and the automatic pairing of modes. This part is concluded with a ﬂowchart suggesting a systematic approach to a FEMU project. In the second part of the text two bridge case studies are presented. In the ﬁrst case study a railway bridge in the north of Sweden is studied. A detailed FE bridge model from a previous project is used as a simulation model for extraction of modal data by eigenvalue analysis. Then simpliﬁed models are created and attempts to update these models are performed. The updating parameters are chosen based on a simple sensitivity analysis. Tests are performed to investigate the inﬂuence of chosen updating parameters and objective function on the computational cost and the quality of the updated model. Case study number two is more comprehensive and focuses on the sensitivity analysis for the choice of updating parameters and on the choice of objective function. A road bridge in the Stockholm area is used and as for case study one a detailed model from a previous project is used as simulation model. Also a new criteria for the automatic pairing of modes is presented and tested. In the end an attempt to verify two of the updated models is performed.

QC 20150825

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44

Ara?jo, Allan David Garcia de. "Uma proposi??o para o c?lculo de mapas de disparidade de imagens est?reo usando um interpolador neural baseado em fun??es de base radial". Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15323.

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
This study aims to seek a more viable alternative for the calculation of differences in images of stereo vision, using a factor that reduces heel the amount of points that are considered on the captured image, and a network neural-based radial basis functions to interpolate the results. The objective to be achieved is to produce an approximate picture of disparities using algorithms with low computational cost, unlike the classical algorithms
O presente trabalho visa buscar uma alternativa mais vi?vel para o c?lculo das disparidades em imagens de vis?o est?reo, utilizando um fator de salto que reduz a quantidade de pontos que s?o considerados da imagem capturada, e uma rede neural baseada em fun??es de base radial para interpolar os resultados obtidos. O objetivo a ser alcan?ado ? produzir uma imagem de disparidades aproximada da real com algoritmos de baixo custo computacional, diferentemente dos algoritmos tradicionais

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45

Oliveira, Sabrina David de. "Correlação entre os resultados de avaliações neuropsicológicas e o desempenho em discriminação condicional com crianças com Transtorno do Espectro do Autismo". Universidade Federal de São Carlos, 2017. https://repositorio.ufscar.br/handle/ufscar/9031.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Neuropsychology is a science that allows one to draw the profile of cognitive impairment and skills preserved in order to design possible treatments and appropriate educational practices, aiming for better quality of life of the individual. Among the cognitive abilities investigated by neuropsychology, executive functions refers to a system that manages the cognitivebehavioral resources, with the purpose of behavior planning and regulation. This study is a correlational basic research aimed to verify whether the results found in neuropsychological evaluations of executive functions in children with Autism Spectrum Disorder (ASD) are predictive of or show any correlation with the performance of these children in conditional discrimination via identity matching-to-sample (MTS) tasks. A battery of neuropsychological tests were used to evaluate executive function to identify participants’ existing and missing skills, with possible quantification and qualification of the results. The tests used were Wisconsin, Test Tracks Pre-School, Corsi blocks and Attention Test for Cancellation. A portable microcomputer and the Master computer program were used to present MTS tasks. The participants were 13 children with ASD, aged 4 to 12 years, regularly enrolled in a Special Institution / Regular Education School. The correlations revealed significant associations between neuropsychological tests and MTS tasks performance. In general, it was observed that the lower the performance in Test Wisconsin, more perseverative responses were presented and higher correlation was found with the MTS tasks. It was also observed that the better the performance in the Cancellation and trails tests, better performance on MTS tasks. The attention and cognitive flexibility may be pre-requisites for better performances in MTS tasks. Future research could further explore the MTS tasks for evaluation of cognitive and attentional flexibility and intervention of individuals with ASD. Another possibility is to check whether training with several exemplars of identity MTS would improve performance on neuropsychological tests.
A neuropsicologia trata-se de uma ciência que permite traçar o perfil dos comprometimentos cognitivos e das habilidades preservadas afim de possível delineamento de tratamentos e práticas educativas adequadas, almejando melhor qualidade de vida do indivíduo. Assim essa é uma pesquisa básica correlacional, cujo objetivo foi verificar se os resultados encontrados em avaliações neuropsicológicas das funções executivas em crianças com Transtorno do Espectro do Autismo (TEA) são preditivas de ou tem alguma correlação com o desempenho dessas crianças em discriminação condicional por meio de tarefas de escolha de acordo com o modelo (MTS) de identidade. Para isso foi utilizado uma bateria de testes neuropsicológicos para avaliação das funções executivas para identificar habilidades preservadas e comprometidas dos participantes, com possível quantificação e qualificação dos resultados. Os testes utilizados foram: Wisconsin, Teste de Trilhas para Pré-Escolares, Blocos de Corsi e Teste de Atenção por Cancelamento. Foram utilizados também um microcomputador portátil e o programa computacional Mestre para apresentar as tarefas de MTS. Os participantes da pesquisa foram 13 crianças com Transtorno do Espectro do Autismo, com idade entre 4 e 12 anos, regularmente matriculadas em uma Instituição Especial/ Escola Regular de Ensino. As correlações revelaram associações significativas entre os testes neuropsicológicos e as tarefas de MTS. De maneira geral, foi possível observar que quanto menor o desempenho no Teste Wisconsin, mais respostas perseverativas foram apresentadas e maior a correlação com as tarefas de MTS e que quanto melhor foi o desempenho nos testes de Cancelamento e de Trilhas, melhor o desempenho nas tarefas de MTS. Esses resultados sugerem que a atenção e a flexibilidade cognitiva são quesitos para o melhor cumprimento das tarefas de MTS. Pesquisas futuras poderão explorar melhor as tarefas de MTS para avaliação de flexibilidade cognitiva e atencional e intervenção de indivíduos com TEA. Outra possibilidade é verificar se treinos com vários exemplares de relações de identidade em tarefas de MTS melhorariam o desempenho nos testes neuropsicológicos.

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46

Barkouki, Houda. "Rational Lanczos-type methods for model order reduction". Thesis, Littoral, 2016. http://www.theses.fr/2016DUNK0440/document.

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La solution numérique des systèmes dynamiques est un moyen efficace pour étudier des phénomènes physiques complexes. Cependant, dans un cadre à grande échelle, la dimension du système rend les calculs infaisables en raison des limites de mémoire et de temps, ainsi que le mauvais conditionnement. La solution de ce problème est la réduction de modèles. Cette thèse porte sur les méthodes de projection pour construire efficacement des modèles d'ordre inférieur à partir des systèmes linéaires dynamiques de grande taille. En particulier, nous nous intéressons à la projection sur la réunion de plusieurs sous-espaces de Krylov standard qui conduit à une classe de modèles d'ordre réduit. Cette méthode est connue par l'interpolation rationnelle. En se basant sur ce cadre théorique qui relie la projection de Krylov à l'interpolation rationnelle, quatre algorithmes de type Lanczos rationnel pour la réduction de modèles sont proposés. Dans un premier temps, nous avons introduit une méthode adaptative de type Lanczos rationnel par block pour réduire l'ordre des systèmes linéaires dynamiques de grande taille, cette méthode est basée sur l'algorithme de Lanczos rationnel par block et une méthode adaptative pour choisir les points d'interpolation. Une généralisation de ce premier algorithme est également donnée, où différentes multiplicités sont considérées pour chaque point d'interpolation. Ensuite, nous avons proposé une autre extension de la méthode du sous-espace de Krylov standard pour les systèmes à plusieurs-entrées plusieurs-sorties, qui est le sous-espace de Krylov global. Nous avons obtenu des équations qui décrivent cette procédure. Finalement, nous avons proposé une méthode de Lanczos étendu par block et nous avons établi de nouvelles propriétés algébriques pour cet algorithme. L'efficacité et la précision de tous les algorithmes proposés, appliqués sur des problèmes de réduction de modèles, sont testées dans plusieurs exemples numériques
Numerical solution of dynamical systems have been a successful means for studying complex physical phenomena. However, in large-scale setting, the system dimension makes the computations infeasible due to memory and time limitations, and ill-conditioning. The remedy of this problem is model reductions. This dissertations focuses on projection methods to efficiently construct reduced order models for large linear dynamical systems. Especially, we are interesting by projection onto unions of Krylov subspaces which lead to a class of reduced order models known as rational interpolation. Based on this theoretical framework that relate Krylov projection to rational interpolation, four rational Lanczos-type algorithms for model reduction are proposed. At first, an adaptative rational block Lanczos-type method for reducing the order of large scale dynamical systems is introduced, based on a rational block Lanczos algorithm and an adaptive approach for choosing the interpolation points. A generalization of the first algorithm is also given where different multiplicities are consider for each interpolation point. Next, we proposed another extension of the standard Krylov subspace method for Multiple-Input Multiple-Output (MIMO) systems, which is the global Krylov subspace, and we obtained also some equations that describe this process. Finally, an extended block Lanczos method is introduced and new algebraic properties for this algorithm are also given. The accuracy and the efficiency of all proposed algorithms when applied to model order reduction problem are tested by means of different numerical experiments that use a collection of well known benchmark examples

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47

Perez, William Ferreira. "Equivalência de estímulos e transferência de função: avaliando os efeitos dos controles por seleção e por rejeição". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/47/47132/tde-07022013-103637/.

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Em uma tarefa de emparelhamento com o modelo envolvendo duas escolhas, o participante pode aprender tanto a selecionar o estímulo correto (controle por seleção) quanto a rejeitar o estímulo incorreto (controle por rejeição). O presente trabalho investigou o efeito dos controles por seleção e por rejeição sobre a formação de classes de estímulos equivalentes e sobre a transferência de função discriminativa. O Capítulo 1 apresenta uma revisão metodológica que sistematizou os procedimentos utilizados para inferir a ocorrência desses controles, bem como os procedimentos utilizados para manipulá-los experimentalmente. O Capítulo 2 apresenta um experimento que investigou o efeito da manipulação da observação dos estímulos de comparação sobre o estabelecimento dos controles por seleção e por rejeição. Participantes adultos foram submetidos a um treino de discriminações condicionais por meio do procedimento de emparelhamento com o modelo com observação requerida (MTS-OR). Os resultados sugerem que a ocorrência do controle por seleção foi mais provável para os participantes que foram exigidos observar o S+ ao longo de todas as tentativas de treino; o controle por rejeição só ocorreu para os participantes que foram exigidos observar o S-. Nesse último caso, impedir os participantes de observar o S+ favoreceu o estabelecimento do controle pelo S-. Por fim, o Capítulo 3 apresenta um conjunto de experimentos que avaliou o efeito dos controles por seleção e por rejeição sobre os testes de formação de classe de equivalência e sobre a transferência de função discriminativa. O procedimento de MTS-OR, aliado ao uso de diferentes proporções de S+/S-, permitiu a manipulação experimental dos controles investigados. A transferencia de função foi avaliada por meio de uma tarefa discriminativa simples sucessiva envolvendo respostas ao teclado. Os resultados sugerem que os testes de reflexividade, bem como os de transitividade e de equivalência envolvendo um nodo, foram afetados diferencialmente por esses controles. Os resultados dos testes de transferência de função sugerem a formação de diferentes classes a depender do controle estabelecido, por seleção ou por rejeição
In a two-choice matching-to-sample task, the participant might learn either to select the correct stimulus (select control) or to reject the incorrect one (reject control). The present dissertation investigated the effects of select and reject controls upon equivalence-class formation and transfer of discriminative function. Chapter 1 presents a methodological review that analyzed procedures used to infer the occurrence of such controls and also procedures used to experimentally manipulate them. Chapter 2 presents an experiment that evaluated the effects of manipulating observing responses towards comparison stimuli upon the establishment of select or reject controls. Adults participated and were exposed to a conditional discrimination training in a matching-tosample task with observing requirements (MTS-OR). Results suggest that select control was more likely to occur for participants that were required to observe the S+ in every training trial; reject control occurred only for participants that were required to observe the S- in every training trial. In this last case, preventing participants from observing the S+ also increased the chances of control by the S-. Finally, Chapter 3 presents experiments that evaluated the effects of select or reject controls upon equivalence-class-formation tests and transfer of discriminative function. The MTS-OR procedure, allied with different proportions of S+/S-, allowed manipulating the controls that were investigated. The transfer of function was evaluated by means of a simple successive discrimination task involving key-pressing responses on the keyboard. The results suggest that the reflexivity tests, and also the one-node transitivity and equivalence tests, were differentially affected by such controls. Transfer of function test results suggest the formation of different classes depending on the control that was established, select or reject

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48

Gil, Rodríguez Raquel. "Digital camera colour processing pipeline for high dynamic range imaging and colour stabilisation for cinema". Doctoral thesis, Universitat Pompeu Fabra, 2018. http://hdl.handle.net/10803/664378.

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In this thesis we focus on two diﬀerent image processing challenges: high dynamic range (HDR) image/video generation, and colour matching. In both cases, we redeﬁne these tasks by taking into account the prior knowledge from the diﬀerent processes the camera performs when capturing the image. High dynamic range techniques have recently become very popular, thanks to the emergence of HDR recording and displaying technology. We propose two diﬀerent approaches for HDR creation, one for still images, and one for video creation. In case of still images, most of previous methods follow a multiple exposure combination approach. These methods share a set of building assump-tions: i) the full dynamic range of the scene can be recovered, ii) colour channels are independent, and iii) the camera response function remains constant while varying the exposure time. First, we highlight how these assumptions do not apply in general for digital cameras, and then, we propose a method to im-prove multiple exposure combination. Our results outperform state-of-the-art multiple exposure techniques.In case of HDR video, we present a simple and aﬀordable method to gen-erate high quality video from an HDR scene. Our input is an interlaced video alternating row pairs with diﬀerent ISO values, as some DSLR camera models can provide. The proposed algorithm involves two main steps: i) the compu-tation of two single-ISO full-frame images (one for each ISO value) using an inpainting-based deinterlacing method, and ii) the linear combination of the full-frame ISO’s into a single HDR frame. Finally, the results are tone-mapped into an LDR frame ready for display. Results are free of ghosting artefacts and present little noise.Colour matching approaches attempt to transfer the colours of a reference image, to another source image. In this context, we focus on colour matching two images taken from the same scene. First, we propose a method that mod-iﬁes logarithmic encoded images, used in cinema for HDR content, in order to behave as gamma encoded images, used in most digital cameras. Then, we ex-tend a previous approach deﬁned just for gamma encoded images. We redeﬁne the transformation between the two images, by considering a projective trans-form, and we estimate the method parameters in a single optimisation step. The method outperforms the state-of-the-art methods and can handle real-life examples.
En aquesta tesi ens centrem en dos problemes de processament d’imatges diferents: generació d’imatge/vídeo d’alt rang dinàmic (HDR) i coloració. En tots dos casos, redeﬁnim aquestes tasques tenint en compte el coneixement previ dels diferents processos que realitza la càmera en capturar la imatge. Actualment, les tèniques d’alt rang dinàmic s’han tornat molt populars, gràcies a l’aparició de la tecnologia per capturar i visualitzar HDR. Proposem dos enfocaments diferents per a la creació d’HDR, un per a imatges i un altre per a la creació de video. En el cas d’imatges, la majoria de mètodes combinen múltiples exposicions. Aquests mètodes comparteixen un conjunt d’hipòtesis: i) la recuperació del rang dinàmic complet de l’escena, ii) els canals de color són independents, i iii) la funció de resposta de la càmera es manté constant mentre es varia el temps d’exposició. En primer lloc, destaquem com aquestes suposicions no s’apliquen, en general, a les càmeres digitals, i després proposem un mètode per millorar aquesta tècnica. Els nostres resultats superen l’estat de l’art. En el cas de vídeo HDR, presentem un mètode senzill i assequible per generar vídeos d’alta qualitat d’una escena HDR. El nostre input és un vídeo entrellaçat alternant parells de ﬁleres amb diferents valors d’ISO, com alguns models de càmeres DSLR poden proporcionar. L’algorisme inclou dos passos principals: i) el càlcul de dues imatges full-frame ISO (una per a cada valor d’ISO) utilizant un mètode de desentrella¸cat basat en inpainting, ii) la combinació lineal dels ISOs full-frame en un HDR únic. Finalment, els resultats es mapegen tonalment per obtenir un LDR per mostrar per pantalla. Els resultats no tenen artefactes de ghosting i presenten poc soroll. Els mètodes d’igualació de colors intenten transferir els colors d’una imatge de referència, a una altra imatge d’origen. En aquest context, ens centrem en el cas de dues imatges capturades a la mateixa escena. En primer lloc, proposem un mètode que modiﬁca imatges codiﬁcades logarítmicament, utilitzades en el cinema per a continguts HDR, per tal de comportar-se com imatges gamma codiﬁcades, que s’utilitzen en la majoria de les càmeres digitals. A continuació, extenem un mètode deﬁnit prèviament només per imatges gamma codiﬁcades, redeﬁnint la transformació entre les dues imatges, considerant una transformació projectiva i estimant els paràmetres del mètode en un únic pas d’optimització. El mètode supera l’estat de l’art i pot tractar exemples de la vida real.

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49

Olofsson, Anders. "Modern Stereo Correspondence Algorithms : Investigation and Evaluation". Thesis, Linköping University, Information Coding, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-57853.

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Many different approaches have been taken towards solving the stereo correspondence problem and great progress has been made within the field during the last decade. This is mainly thanks to newly evolved global optimization techniques and better ways to compute pixel dissimilarity between views. The most successful algorithms are based on approaches that explicitly model smoothness assumptions made about the physical world, with image segmentation and plane fitting being two frequently used techniques.

Within the project, a survey of state of the art stereo algorithms was conducted and the theory behind them is explained. Techniques found interesting were implemented for experimental trials and an algorithm aiming to achieve state of the art performance was implemented and evaluated. For several cases, state of the art performance was reached.

To keep down the computational complexity, an algorithm relying on local winner-take-all optimization, image segmentation and plane fitting was compared against minimizing a global energy function formulated on pixel level. Experiments show that the local approach in several cases can match the global approach, but that problems sometimes arise – especially when large areas that lack texture are present. Such problematic areas are better handled by the explicit modeling of smoothness in global energy minimization.

Lastly, disparity estimation for image sequences was explored and some ideas on how to use temporal information were implemented and tried. The ideas mainly relied on motion detection to determine parts that are static in a sequence of frames. Stereo correspondence for sequences is a rather new research field, and there is still a lot of work to be made.

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50

Chouaki, Amar. "Recalage de modèles dynamiques de structures avec amortissement". Cachan, Ecole normale supérieure, 1997. http://www.theses.fr/1997DENS0034.

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La maitrise de modèles de plus en plus complexes en mécanique est une préoccupation constante tant au niveau industriel qu'en recherche. Le problème auquel nous nous intéressons ici concerne le recalage de l'amortissement dans les modèles dynamiques de structures à partir de fonctions de réponses en fréquences. D'une manière plus générale, l'appréciation de la qualité d'un modèle est le problème central. Bien des propositions ont été faites mais peu ont une interprétation mécanique forte ; la méthode développée au LMT, depuis le début des années quatre vingt, est basée sur la notion d'erreur en relation de comportement. Après de récents développements (voir le rapport interne 150), cette approche tient compte des effets d'amortissement, et plus généralement des effets non-linéaires dus au comportement des matériaux. De plus, elle intègre tous type de résultats expérimentaux disponibles (statiques, forces et vibrations libres). L'étude présentée s'intéresse particulièrement à l'amortissement. Le recalage de l'amortissement dans le comportement dynamique des structures nécessite une représentation correcte de celui-ci. Son influence peut apparaitre tant au niveau structural qu'au niveau des liaisons entre sous-structures. La première partie de l'exposé concerne l'étude de la sensibilité de l'erreur en relation de comportement aux effets d'amortissement. Puis, dans une seconde partie, nous nous intéressons à l'influence du bruit de mesure sur le processus de recalage. Enfin, nous montrons sur différents exemples l'aptitude de la méthode à recaler l'amortissement et à l'identifier dans les liaisons entre sous-structures. Les modèles considérés sont linéaires et les résultats d'essais exploités sont de type fonctions de réponses en fréquences, incomplets et entaches de bruit de mesure.

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