Дисертації з теми "Action algorithms"
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Cox, Jürgen 1970. "Solution of sign and complex action problems with cluster algorithms." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8646.
Повний текст джерелаIncludes bibliographical references (p. [105]-109) and index.
Two kinds of models are considered which have a Boltzmann weight which is either not real or real but not positive and so standard Monte Carlo methods are not applicable. These sign or complex action problems are solved with the help of cluster algorithms. In each case improved estimators for the Boltzmann weight are constructed which are real and positive. The models considered belong to two classes: fermionic and non-fermionic models. An example for a non-fermionic model is the Potts model approximation to QCD at non-zero baryon density. The three-dimensional three-state Potts model captures the qualitative features of this theory. It has a complex action and so the Boltzmann weight cannot be interpreted as a probability. The complex action problem is solved by using a cluster algorithm. The improved estimator for the complex phase of the Boltzmann factor is real and positive and is used for importance sampling. The first order deconfinement transition line is investigated and the universal behavior at its critical endpoint is studied.
(cont.) An example for a fermionic model with a sign problem are staggered fermions with 2 flavors in 3+1 dimensions. Here the sign is connected to the permutation sign of fermion world lines and is of nonlocal nature. Cluster flips change the topology of the fermion world lines and they have a well defined effect on the permutation sign independent of the other clusters. The sign problem is solved by suppressing those clusters whose contribution to the partition function and observables of interest would be zero. We confirm that the universal critical behavior of the finite temperature chiral phase transition is the one of the three dimensional Ising model. We also study staggered fermions with one flavor in 2+1 dimensions and confirm that the chiral phase transition then belongs to the universality class of the two dimensional Ising model.
by Jürgen Cox.
Ph.D.
Oppon, Ekow CruickShank. "Synergistic use of promoter prediction algorithms: a choice of small training dataset?" Thesis, University of the Western Cape, 2000. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_8222_1185436339.
Повний текст джерелаPromoter detection, especially in prokaryotes, has always been an uphill task and may remain so, because of the many varieties of sigma factors employed by various organisms in transcription. The situation is made more complex by the fact, that any seemingly unimportant sequence segment may be turned into a promoter sequence by an activator or repressor (if the actual promoter sequence is made unavailable). Nevertheless, a computational approach to promoter detection has to be performed due to number of reasons. The obvious that comes to mind is the long and tedious process involved in elucidating promoters in the &lsquo
wet&rsquo
laboratories not to mention the financial aspect of such endeavors. Promoter detection/prediction of an organism with few characterized promoters (M.tuberculosis) as envisaged at the beginning of this work was never going to be easy. Even for the few known Mycobacterial promoters, most of the respective sigma factors associated with their transcription were not known. If the information (promoter-sigma) were available, the research would have been focused on categorizing the promoters according to sigma factors and training the methods on the respective categories. That is assuming that, there would be enough training data for the respective categories. Most promoter detection/prediction studies have been carried out on E.coli because of the availability of a number of experimentally characterized promoters (+- 310). Even then, no researcher to date has extended the research to the entire E.coli genome.
Wanek, J. F. "Direct action of radiation on mummified cells : modelling of computed tomography by Monte Carlo algorithms." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1432807/.
Повний текст джерелаUmuhoza, Denise. "Metric of trust for mobile ad hoc networks using source routing algorithms." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_8946_1183465240.
Повний текст джерелаThis thesis proposed and presented technical details of new probabilistic metrics of trust in the links wireless ad hoc networks for unobservable communications. In covert communication networks, only the end nodes are aware of the communication characteristics of the overall path. The most widely used protocols of ad hoc networks was overviewed. The routing protocols of ad hoc networks with trust considerations and select Destination Sequence Routing, a protocol that can be used in distributed ad hoc network settings for path discovery, was also reviewed. It establishes a path through which all packets sent by a source must pass to the destination. The end nodes are responsible for examining the statistics of the received packets and deriving inferences on path feature variations which are used for computing new trust metrics. When a path is judged not trustworthy based on the metrics, the Destination Sequence Routing is informed to undertake a new trusted path discovery between the end points. The thesis added a new feature based on the quality of service parameters of the path to create trust in the links in recognition of attacks.
Brualla, Barberà Llorenç. "Path integral Monte Carlo. Algorithms and applications to quantum fluids." Doctoral thesis, Universitat Politècnica de Catalunya, 2002. http://hdl.handle.net/10803/6577.
Повний текст джерелаThe first part encompasses a study of the different ingredients of a PIMC code: action, sampling and physical property estimators. Particular attention has been paid to Li-Broughton's higher order approximation to the action. Regarding sampling, several collective movement methods have been derived, including the bisection algorithm, that has been thoroughly tested. We also include a study of estimators for different physical properties, such as, the energy (through the thermodynamic and virial estimators), the pair distribution function, the structure factor, and the momentum distribution.
In relation to the momentum distribution, we have developed a novel algorithm for its estimation, the trail method. It surmounts some of the problems exposed by previous approaches, such as the open chain method or McMillan's algorithm.
The Richardson extrapolation used within PIMC simulations, is another contribution of this thesis. Up until now, this extrapolation has not been used in this context. We present studies of the energy dependence on the number of "beads", along with the betterment provide by the Richardson extrapolation.
Inasmuch as our goal is to perform research of quantum liquids at finite temperature, we have produced a library of codes, written from scratch, that implement most of the features theoretically developed. The most elaborated parts of these codes are included in some of the appendixes.
The second part shows two different applications of the algorithms coded. We present results of a PIMC calculation of the momentum distribution of Ne and normal 4He at low temperatures. In the range of temperatures analysed, exchanges can be disregarded and both systems are considered Boltzmann quantum liquids. Their quantum character is well reflected in their momentum distributions witch show clear departures from the classical limit. The PIMC momentum distributions which show clear departures from the classical limit. The PIMC momentum distributions are sampled using the trail method. Kinetic energies of both systems, as a function of temperature and at a fixed density, are also reported.
Finally, the solid-liquid neon phase transition along the 35 K isotherm has been characterized.While thermodynamic properties of the solid phase are well known the behaviour of some properties, such as the energy or the dessity, during the trasition presen6 some uncertainties For example, experimental data for the place diagram, which determines solid and liquid boundaries, present sizeable differences. The temperature chosen is high enough so that Bose or Fermi statistics corrections are small, although the system is strongly quantum mechanical. The results obtained show a discontinuity in the kinetic energy during the transition.
Празднікова, Маргарита Олександрівна. "Додаток на базі Android «Кіногід» для керування контентом". Bachelor's thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/34968.
Повний текст джерелаStructure and scope of work. The explanatory note of the diploma project consists of six sections, contains 8 figures, 5 tables, 5 appendices, 45 sources. Thesis project is dedicated to the development of an application based on Android "Kinogid". In the section analysis of existing solutions for systematization of information about film screenings will consider the existing services, their functions and shortcomings that need to be improved. The section analysis of programming languages and technologies of Android application development considers theoretical aspects of execution methods causing all possible complications and shortcomings of different systems in Android application development. Theoretical information on the topic of the diploma. The methods of application development, algorithms of actions at the set task, and also the decision of a problem which could arise are shown. The section features of the implementation of the software application for the mobile platform shows theoretical information about the algorithms that were used. In the section analysis of the application the methods of testing the application, analysis of further improvement are explained.
Stephanos, Dembe. "Machine Learning Approaches to Dribble Hand-off Action Classification with SportVU NBA Player Coordinate Data." Digital Commons @ East Tennessee State University, 2021. https://dc.etsu.edu/etd/3908.
Повний текст джерелаGill, Harnavpreet Singh. "Computationally Robust Algorithms for Hypoid Gear Cutting and Contact Line Determination using Ease-Off Methodology." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587499768039312.
Повний текст джерелаChaaraoui, Alexandros Andre. "Vision-based Recognition of Human Behaviour for Intelligent Environments." Doctoral thesis, Universidad de Alicante, 2014. http://hdl.handle.net/10045/36395.
Повний текст джерелаSeita, Marcelo Ruiz. "Simulação multi agente em mercados financeiros artificiais utilizando algoritmos genéticos." reponame:Repositório Institucional do FGV, 2014. http://hdl.handle.net/10438/11936.
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Aiming to establish a methodology capable of segregate market’s moments and identifying investors's characteristics acting on a given financial market, this study employs simulations created by an Agent-based Artificial Financial Market, using a Genetic Algorithm to adjust such simulations to the real observed historic data. For this purpose, a Bovespa's index future contracts application was developed. This methodology could easily be extended to other financial markets by simply changing the model's parameters. Over the foundations established by Toriumi et al. (2011), significant contributions were achieved, promoting knowledge enhancements on the chosen target market, as well as on Artificial Financial Market modelling techniques, and also on the application of Genetic Algorithm into financial markets, resulting on experiments and analysis that suggest the efficacy of the methodology herein proposed.
Com o objetivo de estabelecer uma metodologia capaz segregar momentos de mercado e de identificar as características predominantes dos investidores atuantes em um determinado mercado financeiro, este trabalho emprega simulações geradas em um Mercado Financeiro Artificial baseado em agentes, utilizando um Algoritmo Genético para ajustar tais simulações ao histórico real observado. Para tanto, uma aplicação foi desenvolvida utilizando-se o mercado de contratos futuros de índice Bovespa. Esta metodologia poderia facilmente ser estendida a outros mercados financeiros através da simples parametrização do modelo. Sobre as bases estabelecidas por Toriumi et al. (2011), contribuições significativas foram atingidas, promovendo acréscimo de conhecimento acerca tanto do mercado alvo escolhido, como das técnicas de modelagem em Mercados Financeiros Artificiais e também da aplicação de Algoritmos Genéticos a mercados financeiros, resultando em experimentos e análises que sugerem a eficácia do método ora proposto.
Arseneau, Shawn. "Robust image segementation towards an action recognition algorithm." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30234.
Повний текст джерелаThis thesis will investigate the various image processing tools available to obtain the aforementioned action attributes. The applicability of filters, background removal techniques, skin-tone matching, and contouring schemes will all be investigated. A thorough comparison with both existing and novel approaches to action recognition is then discussed. Overall, the temporal based algorithm is best suited for an action recognition application as the spatially based approaches rely too heavily on a priori knowledge of the background scene.
Arseneau, Shawn. "Robust image segmentation towards an action recognition algorithm." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0033/MQ64210.pdf.
Повний текст джерелаDuan, Jie. "Active Control of Vehicle Powertrain Noise Applying Frequency Domain Filtered-x LMS Algorithm." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1243614246.
Повний текст джерелаSingh, Krishna Kant. "Algorithmes pour la dynamique moléculaire restreinte de manière adaptative." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAM067/document.
Повний текст джерелаMolecular Dynamics (MD) is often used to simulate large and complex systems. Although, simulating such complex systems for the experimental time scales are still computationally challenging. In fact, the most computationally extensive step in MD is the computation of forces between particles. Adaptively Restrained Molecular Dynamics (ARMD) is a recently introduced particles simulation method that switches positional degrees of freedom on and off during simulation. Since force computations mainly depend upon the inter-atomic distances, the force computation between particles with positional degrees of freedom off~(restrained particles) can be avoided. Forces involving active particles (particles with positional degrees of freedom on) are computed.In order to take advantage of adaptability of ARMD, we designed novel algorithms to compute and update forces efficiently. We designed algorithms not only to construct neighbor lists, but also to update them incrementally. Additionally, we designed single-pass incremental force update algorithm that is almost two times faster than previously designed two-pass incremental algorithm. These proposed algorithms are implemented and validated in the LAMMPS MD simulator, however, these algorithms can be applied to other MD simulators. We assessed our algorithms on different and diverse benchmarks in both microcanonical ensemble (NVE) and canonical (NVT) ensembles. In the NVE ensemble, ARMD allows users to trade between precision and speed while, in the NVT ensemble, it makes it possible to compute statistical averages faster. In Last, we introduce parallel algorithms for single-pass incremental force computations to take advantage of adaptive restraints using the Message Passage Interface (MPI) standard
Sharp, Graham R. "Recognition algorithms for actions of permutation groups on pairs." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244602.
Повний текст джерелаSosnowski, Scott T. "Approximate Action Selection For Large, Coordinating, Multiagent Systems." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459468867.
Повний текст джерелаBonnefoy, Antoine. "Elimination dynamique : accélération des algorithmes d'optimisation convexe pour les régressions parcimonieuses." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4011/document.
Повний текст джерелаApplications in signal processing and machine learning make frequent use of sparse regressions. Resulting convex problems, such as the LASSO, can be efficiently solved thanks to first-order algorithms, which are general, and have good convergence properties. However those algorithms suffer from the dimension of the problem, which impose the complexity of their iterations. In this thesis we study approaches, based on screening tests, aimed at reducing the computational cost at the iteration level. Such approaches build upon the idea that it is worth dedicating some small computational effort to locate inactive atoms and remove them from the dictionary in a preprocessing stage so that the regression algorithm working with a smaller dictionary will then converge faster to the solution of the initial problem. We believe that there is an even more efficient way to screen the dictionary and obtain a greater acceleration: inside each iteration of the regression algorithm, one may take advantage of the algorithm computations to obtain a new screening test for free with increasing screening effects along the iterations. The dictionary is henceforth dynamically screened instead of being screened statically, once and for all, before the first iteration. Our first contribution is the formalisation of this principle and its application to first-order algorithms, for the resolution of the LASSO and Group-LASSO. In a second contribution, this general principle is combined to active-set methods, whose goal is also to accelerate the resolution of sparse regressions. Applying the two complementary methods on first-order algorithms, leads to great acceleration performances
Novoa, Del Toro Elva Maria. "Detecting active modules in multiplex biological networks." Thesis, Aix-Marseille, 2020. http://theses.univ-amu.fr.lama.univ-amu.fr/200514_NOVOADELTORO_173hc776k263go601dzf_TH(1).pdf.
Повний текст джерелаGene expression is regulated in time, cell types and conditions. We have access to technologies allowing us to measure the gene expression. We can therefore calculate the differences in gene expression between patients and controls, thereby identifying deregulated genes. We can also try to find significant enrichment of one or more cellular functions from the list of deregulated genes. I analyzed transcriptomics data corresponding to Hutchinson-Gilford Progeria Syndrome (HGPS) patients and healthy controls. Our analyses led to the identification of candidate RNAs for experimental validation.Inside cells the molecules do not act isolated, but they interact to accomplish their functions. Nowadays, we have experimental techniques to decipher these interactions on a large scale. Biological interactions can be represented as networks, where the nodes represent molecules, and the edges represent physical and/or functional relationships. The main hypothesis I followed during my thesis is that dense subnetworks associated to an overall expression deregulation correspond to affected cellular processes in patients. I integrated gene expression data and networks to identify such modules. I developed MOGAMUN, a multi-objective genetic algorithm that seeks for active modules. MOGAMUN is the first active module identification algorithm able to consider multiplex networks, i.e. networks composed of different layers of biological interactions
Bellino, Kathleen Ann. "Computational Algorithms for Face Alignment and Recognition." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/32847.
Повний текст джерелаMaster of Science
Nkansah-Gyekye, Yaw. "An intelligent vertical handoff decision algorithm in next generation wireless networks." Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_2726_1307443785.
Повний текст джерелаThe objective of the thesis research is to design such vertical handoff decision algorithms in order for mobile field workers and other mobile users equipped with contemporary multimode mobile devices to communicate seamlessly in the NGWN. In order to tackle this research objective, we used fuzzy logic and fuzzy inference systems to design a suitable handoff initiation algorithm that can handle imprecision and uncertainties in data and process multiple vertical handoff initiation parameters (criteria)
used the fuzzy multiple attributes decision making method and context awareness to design a suitable access network selection function that can handle a tradeoff among many handoff metrics including quality of service requirements (such as network conditions and system performance), mobile terminal conditions, power requirements, application types, user preferences, and a price model
used genetic algorithms and simulated annealing to optimise the access network selection function in order to dynamically select the optimal available access network for handoff
and we focused in particular on an interesting use case: vertical handoff decision between mobile WiMAX and UMTS access networks. The implementation of our handoff decision algorithm will provide a network selection mechanism to help mobile users select the best wireless access network among all available wireless access networks, that is, one that provides always best connected services to users.
Bahramgiri, Moshen. "Algorithmic approaches to graph states under the action of local Clifford groups." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38936.
Повний текст джерелаIncludes bibliographical references (p. 87-88).
Graph states are quantum states (quantum codes) in qn-dimensional space ... (q being a power of some prime number) which can be described by graphs with edges labeled from the field of order q, Fq. Graph states are determined as a common eigenvector of independent elements of the n-fold Pauli group, on which the local Clifford group has a natural action. This action induces the natural action of the local Clifford group on graph states and hence, its action on graphs. Locally equivalent graphs can be described using this action. For q being a prime number, two graphs are locally equivalent when they are located on the same orbit of this action, in other words, when there is an element of the local Clifford group mapping one graph to the other one. When q is some power of a prime number, the definition of this action is the natural generalization of this action in the case where q is prime. We translate the action of local Clifford groups on graphs to a set of linear and quadratic equations in the field F,. In the case that q is an odd number, given two arbitrary graphs, we present an efficient algorithm (polynomial in n) to verify whether these graphs are locally equivalent or not. Moreover, we present a computational method to calculate the number of inequivalent graph states. We give some estimations on the size of the orbits of this action on graphs, and prove that when either q is equal to 2 or is an odd number, the number of inequivalent quantum codes (i.e., the number of classes of equivalency) is equal to ..., which is essentially as large as the total number of graphs.
by Mohsen Bahramgiri.
Ph.D.
Ahmed, Fareed. "Un nouvel a priori de formes pour les contours actifs." Thesis, Tours, 2014. http://www.theses.fr/2014TOUR4008/document.
Повний текст джерелаActive contours are widely used for image segmentation. There are many implementations of active contours. The greedy algorithm is being regarded as one of the fastest and stable implementations. No matter which implementation is being employed, the segmentation results suffer greatly in the presence of occlusion, context noise, concavities or abnormal deformation of shape. If some prior knowledge about the shape of the object is available, then its addition to an existing model can greatly improve the segmentation results. In this thesis inclusion of such shape constraints for explicit active contours is being implemented. These shape priors are introduced through the use of robust Fourier based descriptors which makes them invariant to the translation, scaling and rotation factors and enables the deformable model to converge towards the prior shape even in the presence of occlusion and contextual noise. Unlike most existing methods which compare the reference shape and evolving contour in the spatial domain by applying the inverse transforms, our proposed method realizes such comparisons entirely in the descriptor space. This not only decreases the computational time but also allows our method to be independent of the number of control points chosen for the description of the active contour. This formulation however, may introduce certain anomalies in the phase of the descriptors which affects the rotation invariance. This problem has been solved by an original algorithm. Experimental results clearly indicate that the inclusion of these shape priors significantly improved the segmentation results of the active contour model being used
Duvenage, Eugene. "miRNAMatcher: High throughput miRNA discovery using regular expressions obtained via a genetic algorithm." Thesis, University of the Western Cape, 2008. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_5752_1266536340.
Повний текст джерелаIn summary there currently exist techniques to discover miRNA however both require many calculations to be performed during the identification limiting their use at a genomic level. Machine learning techniques are currently providing the best results by combining a number of calculated and statistically derived features to identify miRNA candidates, however almost all of these still include computationally intensive secondary-structure calculations. It is the aim of this project to produce a miRNA identification process that minimises and simplifies the number of computational elements required during the identification process.
Ndiaye, Eugene. "Safe optimization algorithms for variable selection and hyperparameter tuning." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLT004/document.
Повний текст джерелаMassive and automatic data processing requires the development of techniques able to filter the most important information. Among these methods, those with sparse structures have been shown to improve the statistical and computational efficiency of estimators in a context of large dimension. They can often be expressed as a solution of regularized empirical risk minimization and generally lead to non differentiable optimization problems in the form of a sum of a smooth term, measuring the quality of the fit, and a non-smooth term, penalizing complex solutions. Although it has considerable advantages, such a way of including prior information, unfortunately introduces many numerical difficulties both for solving the underlying optimization problem and to calibrate the level of regularization. Solving these issues has been at the heart of this thesis. A recently introduced technique, called "Screening Rules", proposes to ignore some variables during the optimization process by benefiting from the expected sparsity of the solutions. These elimination rules are said to be safe when the procedure guarantees to not reject any variable wrongly. In this work, we propose a unified framework for identifying important structures in these convex optimization problems and we introduce the "Gap Safe Screening Rules". They allows to obtain significant gains in computational time thanks to the dimensionality reduction induced by this method. In addition, they can be easily inserted into iterative algorithms and apply to a large number of problems.To find a good compromise between minimizing risk and introducing a learning bias, (exact) homotopy continuation algorithms offer the possibility of tracking the curve of the solutions as a function of the regularization parameters. However, they exhibit numerical instabilities due to several matrix inversions and are often expensive in large dimension. Another weakness is that a worst-case analysis shows that they have exact complexities that are exponential in the dimension of the model parameter. Allowing approximated solutions makes possible to circumvent the aforementioned drawbacks by approximating the curve of the solutions. In this thesis, we revisit the approximation techniques of the regularization paths given a predefined tolerance and we propose an in-depth analysis of their complexity w.r.t. the regularity of the loss functions involved. Hence, we propose optimal algorithms as well as various strategies for exploring the parameters space. We also provide calibration method (for the regularization parameter) that enjoys globalconvergence guarantees for the minimization of the empirical risk on the validation data.Among sparse regularization methods, the Lasso is one of the most celebrated and studied. Its statistical theory suggests choosing the level of regularization according to the amount of variance in the observations, which is difficult to use in practice because the variance of the model is oftenan unknown quantity. In such case, it is possible to jointly optimize the regression parameter as well as the level of noise. These concomitant estimates, appeared in the literature under the names of Scaled Lasso or Square-Root Lasso, and provide theoretical results as sharp as that of theLasso while being independent of the actual noise level of the observations. Although presenting important advances, these methods are numerically unstable and the currently available algorithms are expensive in computation time. We illustrate these difficulties and we propose modifications based on smoothing techniques to increase stability of these estimators as well as to introduce a faster algorithm
Swathanthira, Kumar Murali Murugavel Manjakkattuvalasu. "Implementation of an actuator placement, switching algorithm for active vibration control in flexible structures." Link to electronic thesis, 2002. http://www.wpi.edu/Pubs/ETD/Available/etd-1120102-210634.
Повний текст джерелаKeywords: Actuator placement algorithm; piezoelectric actuators; LQR; Galerkin; supervisory control; active vibration control; FEA; switching policy; dSPACE. Includes bibliographical references (p. 58-64).
Salcburger, Martin. "Semiaktivní systém odpružení vozidla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254452.
Повний текст джерелаCarneiro, Milena Bueno Pereira. "Reconhecimento de íris utilizando algoritmos genéticos e amostragem não uniforme." Universidade Federal de Uberlândia, 2010. https://repositorio.ufu.br/handle/123456789/14276.
Повний текст джерелаO reconhecimento automático de pessoas utilizando-se características da íris é uma eficiente técnica biométrica que está sendo largamente estudada e aplicada em todo o mundo. Diversas etapas de processamento são necessárias para tornar possível a representação e a interpretação da informação contida na íris. Neste trabalho é apresentado o estado da arte de sistemas de reconhecimento de íris onde são citados os trabalhos de maior destaque e as diferentes técnicas empregadas em cada etapa de processamento. São apresentadas implementações de cada etapa de processamento utilizando técnicas tradicionais e, posteriormente, são propostos dois métodos inovadores que têm o objetivo comum de trazer benefícios ao sistema. A primeira etapa de processamento é a localização da região da íris na imagem. O primeiro método proposto neste trabalho apresenta um algoritmo para realizar a localização da íris utilizando os chamados Algoritmos Meméticos. O novo método é comparado a um método clássico e os resultadosnobtidos demonstram vantagens no que diz respeito à eficiência e ao tempo de processamento. Em uma outra etapa de processamento deve haver uma amostragem de pixels na região da íris, de onde são retiradas as informações utilizadas para diferenciar os indivíduos. Tradicionalmente, esta amostragem é realizada de maneira uniforme ao longo de toda a região da íris. É proposto um método de pré-processamento que sugere uma amostragem não uniforme de pixels na região da íris com o objetivo de selecionar o conjunto de pixels que carregam mais informações da estrutura da íris. A busca por esse conjunto de pixels é realizada utilizando-se Algoritmos Genéticos. A aplicação deste novo método aumenta a eficiência do sistema e ainda possibilita a geração de templates binários menores. Neste trabalho é realizado, ainda, um estudos dos chamados Active Shape Models e a sua aplicação para segmentar a região da íris é avaliada. Para a simulação e avaliação dos métodos, foram utilizados dois bancos de imagens de íris públicos e gratuitos: o banco de imagens UBIRIS e o banco de imagens MMU.
Doutor em Ciências
Greenwood, Aaron Blake. "Implementation of Adaptive Filter Algorithms for the Suppression of Thermoacoustic Instabilities." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/31299.
Повний текст джерелаMaster of Science
Araújo, Willian Fernandes. "As narrativas sobre os algoritmos do Facebook : uma análise dos 10 anos do feed de notícias." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/157660.
Повний текст джерелаThis study follows the Facebook News Feed construction throughout its first ten years (2006– 2016). The objective of this research is to describe the way this mechanism and the notion of algorithm were compounded, enacted and transformed during that period. This is achieved through an analysis of the digital content (referred to here as ‘textual devices’) that publicly constructs what the News Feed is and how it functions. This analysis describes the actors involved within this narrative, mapping their objectives and effects. The sample is constructed beginning with the textual devices published on Facebook’s institutional websites: Facebook Blog and Facebook Newsroom. Following the reading of more than 1,000 texts of Facebook and other agents (users, content producers, media, activists, etc.), the most relevant publications were selected, emphasizing situations of change, conflict and controversy. The research approach, which was based on science and technology studies (STS) and actornetwork theory (ANT), involved constructing a body of procedures used to describe the performative character of texts. The current study found that during the development of the News Feed, Facebook’s notion of algorithm has gone through three different phases, referred to here respectively as the Edgerank Algorithm, Right Algorithm and User-centered Algorithm. One of the most interesting findings was that the changes in the News Feed are primarily oriented towards the objective of creating engagement by keeping users connected to Facebook. Engagement is an important commodity within the rationality that emerged from this scenario. It is argued that the News Feed development may be seen as a continuous flow. Another important finding was the notion called algorithmic norm, as a normative logic of visibility that rules the relationship between content producers and the News Feed. The algorithmic norm tends to enact specific judgements and to punish content producers who do not follow what Facebook calls good practices.
Rousselle, Jean-Jacques. "Les contours actifs, une méthode de ségmentation : application à l'imagerie médicale." Tours, 2003. http://www.theses.fr/2003TOUR4032.
Повний текст джерелаThe segmentation methods of images are numerous ; all have advantages but do not give full satisfaction. All must be adapted according to the application which has to be carried out. Active contours or deformable models made it possible to avoid to chain the contour points but require the adjustment of many parameters. Active contours that we have studied are implemented using a greedy algorithm. First, we propose an alternative based on a minimization by genetic algorithm. Then we propose three approaches to regulate the parameters which control the evolution of contour. Design of experiments makes it possible from a set of images to very quickly choose a set of powerful parameters. The genetic algorithms can be used to optimize the parameters. Finally we propose an original approach where the parameters are local and randomly defined. These autonomous snake allow an evolution of contours without any adjustment. The applications use various images, but in particular medical images
Bornschlegell, Augusto Salomao. "Optimisation aérothermique d'un alternateur à pôles saillants pour la production d'énergie électrique décentralisée." Thesis, Valenciennes, 2012. http://www.theses.fr/2012VALE0023/document.
Повний текст джерелаThis work relates the thermal optimization of an electrical machine. The lumped method is used to simulate the temperature field. This model solves the heat equation in three dimensions, in cylindrical coordinates and in transient or steady state. We consider two transport mechanisms: conduction and convection. The evaluation of this model is performed by means of 13 design variables that correspond to the main flow rates of the equipment. We analyse the machine cooling performance by varying these 13 flow rates. Before starting the study of such a complicated geometry, we picked a simpler case in order to better understand the variety of the available optimization tools. The experience obtained in the simpler case is applyed in the resolution of the thermal optimization problem of the electrical machine. This machine is evaluated from the thermal point of view by combining two criteria : the maximum and the mean temperature. Constraints are used to keep the problem consistent. We solved the problem using the gradient based methods (Active-set and Interior-Point) and the Genetic Algorithms
Hossain, M. Alamgir, M. O. Tokhi, and Keshav P. Dahal. "Impact of algorithm design in implementing real-time active control systems." Springer, 2004. http://hdl.handle.net/10454/2597.
Повний текст джерелаLoth, Manuel. "Algorithmes d'Ensemble Actif pour le LASSO." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2011. http://tel.archives-ouvertes.fr/tel-00845441.
Повний текст джерелаAidarous, Yasser. "Optimisation des modèles actifs d'apparence." Rennes 1, 2012. http://www.theses.fr/2012REN1S037.
Повний текст джерелаWe use active appearance models (AAM) to align mouths under differentexpressions. However, the prediction used by this method is very sensitive toinitialization and is time and memory consuming. We replace the classical predictionof AAM with a Nelder & Mead simplex optimization. We use a Gaussian mixture toinitialize the simplex and constraint solutions, using a real time belonging calculation,to belong to a plausible appearances space. The appearance parameters are dividedinto two sets which treated differently: a set of dominant parameters, which havegreat influence on the model, and a set of recessive parameters, which manipulatesthe details of the modeled object. Two new methods are suggested: the first appliesan adapted simplex to all appearance parameters, and the second uses the optimumof an adapted simplex applied to dominant parameters followed by another oneapplied to all parameters. Convergence time and memory used by the simplex-basedmethods are lower than those of classical AAM. These methods have a higherconvergence rates and initialization intervals are wider than those of classical AAM. The comparison of the two proposed methods allows us to select one of themdepending on the required performance of the application
Moura, Carolina Silva de. "Associações sociotécnicas: mediações algorítmicas e a economia das ações no Facebook." Universidade Federal de Goiás, 2018. http://repositorio.bc.ufg.br/tede/handle/tede/8427.
Повний текст джерелаApproved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-05-03T14:53:50Z (GMT) No. of bitstreams: 2 Dissertação - Carolina Silva de Moura - 2018.pdf: 5329584 bytes, checksum: 5bfa61f6504213d3213b09998b948dfa (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Made available in DSpace on 2018-05-03T14:53:50Z (GMT). No. of bitstreams: 2 Dissertação - Carolina Silva de Moura - 2018.pdf: 5329584 bytes, checksum: 5bfa61f6504213d3213b09998b948dfa (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-04-02
Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
The project seeks to map the economy mediated by the association between the algorithms and the user on Facebook turning to the commercial pages.Economics keep a direct relationship with the processes of collecting, storing and articulating data favoring a personalization of content. The first part presents the project regarding the problem, objectives and your relevance. The second delivery of conceptual discussion about algorithms, their developments, research perspectives and which ones are sought in this analysis. The third one deals with the Theory-Actor Network, a theoretical proposal for research to consider symmetrical human and non-human highlightly Latour (1994a, 2012). Therefore, we explore ways of implementing empirical research based on the development of cartography (VENTURINNI, 2010; BARROS, KASTRUP, 2009; ROMAGNOLI, 2009; PRADO FILHO, TETI, 2013). Taking this as a reference, the empirical exercise was carried out from the profile of the researcher on Facebook for a month was observed on based on the selection of some internal and external variables about platform. The following reading exposes the data observed in this analysis that point to an economy based on the circulation of segmented contents based on the actions of the user, in which the user's action deals of algorithm transactions that reverberate is not that it is not News Feed and so the user also carries out their translations in a network that is made and remade in a constant way.
O projeto busca cartografar a economia mediada pela associação entre os algoritmos e o usuário no Facebook voltando-se às páginas comerciais. Economia essa que estabelece relação direta com os processos de coleta, armazenamento e articulação de dados favorecendo a personalização de conteúdo. Na primeira parte apresenta-se o projeto quanto ao problema, objetivos e relevância. A segunda dá seguimento à discussão conceitual sobre algoritmos, seus desdobramentos, perspectivas de pesquisa e quais delas são buscadas nessa análise. A terceira aborda a Teoria Ator-Rede, proposta teórica para a pesquisa por considerar simétricos agentes humanos e não humanos a luz especialmente de Latour (1994a, 2012). Por conseguinte se explora as formas de implementação da pesquisa empírica fundamentada no desenvolvimento de uma cartografia (VENTURINNI, 2010; BARROS, KASTRUP, 2009; ROMAGNOLI, 2009; PRADO FILHO, TETI, 2013). Tomando isso como referência, o exercício empírico, foi realizado a partir do perfil da pesquisadora no Facebook que durante um mês foi observado com base na seleção de algumas variáveis internas e externas à plataforma. A leitura seguinte expõe os dados observados nessa análise que apontam para uma economia pautada na circulação de conteúdos segmentados com base nas ações do usuário, em que o agir dele promove traduções do algoritmo as quais reverberam no que é exposto no Feed de Notícias e assim o usuário também realiza suas traduções em uma rede que se faz e refaz de modo constante.
Liu, Siwei. "Apport d'un algorithme de segmentation ultra-rapide et non supervisé pour la conception de techniques de segmentation d'images bruitées." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4371.
Повний текст джерелаImage segmentation is an important step in many image processing systems and many problems remain unsolved. It has recently been shown that when the image is composed of two homogeneous regions, polygonal active contour techniques based on the minimization of a criterion derived from information theory allow achieving an ultra-fast algorithm which requires neither parameter to tune in the optimized criterion, nor a priori knowledge on the gray level fluctuations. This algorithm can then be used as a fast and unsupervised processing module. The objective of this thesis is therefore to show how this ultra-fast and unsupervised algorithm can be used as a module in the conception of more complex segmentation techniques, allowing to overcome several limits and particularly:- to be robust to the presence of strong inhomogeneity in the image which is often inherent in the acquisition process, such as non-uniform illumination, attenuation, etc.;- to be able to segment disconnected objects by polygonal active contour without complicating the optimization strategy;- to segment multi-region images while estimating in an unsupervised way the number of homogeneous regions in the image.For each of these three problems, unsupervised segmentation techniques based on the optimization of Minimum Description Length criteria have been obtained, which do not require the tuning of parameter by user or a priori information on the kind of noise in the image. Moreover, it has been shown that fast segmentation techniques can be achieved using this segmentation module, while keeping reduced implementation complexity
Oz, Sinan. "Implement Of Three Segmentation Algorithms For Ct Images Of Torso." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12612866/index.pdf.
Повний текст джерелаs method for three level thresholding and a recursive connected component algorithm are combined. The segmentation process is accomplished by first using Extended Otsu&rsquo
s method and then labeling in each consecutive slice. Since there is no information about pixel positions in the outcome of Extended Otsu&rsquo
s method, we perform some processing after labeling to connect pixels belonging with the same tissue. In the second framework, Chan-Vese (CV) method, which is an example of active contour models, and a recursive connected component algorithm are used together. The segmentation process is achieved using CV method without egde information as stopping criteria. In the third and last framework, the combination of watershed transformation and K-means are used as the segmentation method. After segmentation operation, the labeling is performed for the determination of the medical structures. In addition, segmentation and labeling operation is realized for each consecutive slice in each framework. The results of each framework are compared quantitatively with manual segmentation results to evaluate their performances.
Gupta, Vaibhav. "A Characterization of Wireless Network Interface Card Active Scanning Algorithms." Digital Archive @ GSU, 2006. http://digitalarchive.gsu.edu/cs_theses/28.
Повний текст джерелаNguyen, Thi Thanh. "Algorithmes gloutons orthogonaux sous contrainte de positivité." Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0133/document.
Повний текст джерелаNon-negative sparse approximation arises in many applications fields such as biomedical engineering, fluid mechanics, astrophysics, and remote sensing. Some classical sparse algorithms can be straightforwardly adapted to deal with non-negativity constraints. On the contrary, the non-negative extension of orthogonal greedy algorithms is a challenging issue since the unconstrained least square subproblems are replaced by non-negative least squares subproblems which do not have closed-form solutions. In the literature, non-negative orthogonal greedy (NNOG) algorithms are often considered to be slow. Moreover, some recent works exploit approximate schemes to derive efficient recursive implementations. In this thesis, NNOG algorithms are introduced as heuristic solvers dedicated to L0 minimization under non-negativity constraints. It is first shown that the latter L0 minimization problem is NP-hard. The second contribution is to propose a unified framework on NNOG algorithms together with an exact and fast implementation, where the non-negative least-square subproblems are solved using the active-set algorithm with warm start initialisation. The proposed implementation significantly reduces the cost of NNOG algorithms and appears to be more advantageous than existing approximate schemes. The third contribution consists of a unified K-step exact support recovery analysis of NNOG algorithms when the mutual coherence of the dictionary is lower than 1/(2K-1). This is the first analysis of this kind
Mathema, Najma. "Predicting Plans and Actions in Two-Player Repeated Games." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8683.
Повний текст джерелаCabell, Randolph H. III. "A Principal Component Algorithm for Feedforward Active Noise and Vibration Control." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/30461.
Повний текст джерелаPh. D.
Johansson, Sven. "Active Control of Propeller-Induced Noise in Aircraft : Algorithms & Methods." Doctoral thesis, Karlskrona, Ronneby : Blekinge Institute of Technology, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00171.
Повний текст джерелаBuller i vår dagliga miljö kan ha en negativ inverkan på vår hälsa. I många sammanhang, i tex bilar, båtar och flygplan, förekommer lågfrekvent buller. Lågfrekvent buller är oftast inte skadligt för hörseln, men kan vara tröttande och försvåra konversationen mellan personer som vistas i en utsatt miljö. En dämpning av bullernivån medför en förbättrad taluppfattbarhet samt en komfortökning. Att dämpa lågfrekvent buller med traditionella passiva metoder, tex absorbenter och reflektorer, är oftast ineffektivt. Det krävs stora, skrymmande absorbenter för att dämpa denna typ av buller samt tunga skiljeväggar för att förhindra att bullret transmitteras vidare från ett utrymme till ett annat. Metoder som är mera lämpade vid dämpning av lågfrekvent buller är de aktiva. De aktiva metoderna baseras på att en vågrörelse som ligger i motfas med en annan överlagras och de släcker ut varandra. Bullerdämpningen erhålls genom att ett ljudfält genereras som är lika starkt som bullret men i motfas med detta. De aktiva bullerdämpningsmetoderna medför en effektiv dämpning av lågfrekvent buller samtidigt som volymen, tex hos bilkupen eller båt/flygplanskabinen ej påverkas nämnvärt. Dessutom kan fordonets/farkostens vikt reduceras vilket är tacksamt för bränsleförbrukningen. I de flesta tillämpningar varierar bullrets karaktär, dvs styrka och frekvensinnehåll. För att följa dessa variationer krävs ett adaptivt (självinställande) reglersystem som styr genereringen av motljudet. I propellerflygplan är de dominerande frekvenserna i kabinbullret relaterat till propellrarnas varvtal, man känner alltså till frekvenserna som skall dämpas. Man utnyttjar en varvtalssignal för att generera signaler, så kallade referenssignaler, med de frekvenser som skall dämpas. Dessa bearbetas av ett reglersystem som generar signaler till högtalarna som i sin tur generar motljudet. För att ställa in högtalarsignalerna så att en effektiv dämpning erhålls, används mikrofoner utplacerade i kabinen som mäter bullret. För att åstadkomma en effektiv bullerdämpning i ett rum, tex i en flygplanskabin, behövs flera högtalare och mikrofoner, vilket kräver ett avancerat reglersystem. I doktorsavhandlingen ''Active Control of Propeller-Induced Noise in Aircraft'' behandlas olika metoder för att reducera kabinbuller härrörande från propellrarna. Här presenteras olika strukturer på reglersystem samt beräkningsalgoritmer för att ställa in systemet. För stora system där många högtalare och mikrofoner används, samt flera frekvenser skall dämpas, är det viktigt att systemet inte behöver för stor beräkningskapacitet för att generera motljudet. Metoderna som behandlas ger en effektiv dämpning till låg beräkningskostnad. Delar av materialet som presenteras i avhandlingen har ingått i ett EU-projekt med inriktning mot bullerundertryckning i propellerflygplan. I projektet har flera europeiska flygplanstillverkare deltagit. Avhandlingen behandlar även aktiv bullerdämpning i headset, som används av helikopterpiloter. I denna tillämpning har aktiv bullerdämpning används för att öka taluppfattbarheten.
Shieh, Yih-Dar. "Arithmetic Aspects of Point Counting and Frobenius Distributions." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4108/document.
Повний текст джерелаThis thesis consists of two parts. Part 1 studies the decomposition of cohomology groups induced by automorphisms for a family of non-hyperelliptic genus 3 curves with involution, and I investigate the benefit of such decomposition in the computation of Frobenius using Kedlaya's algorithm. The involution of a curve C in this family induces a degree 2 map to an elliptic curve E, which gives a decomposition of the Jacobian of C into E and an abelian surface A, from which the Frobenius on C can be recovered. On E, the characteristic polynomial of the Frobenius can be computed using an efficient and fast algorithm. By working with the cohomology subgroup V of $H^1_{MW}(C)$, we get a constant speed-up over a straightforward application of Kedlaya's method to C. To my knowledge, this is the first use of decomposition of the cohomology induced by an isogeny decomposition of the Jacobian in Kedlaya's algorithm. In Part 2, I propose a new approach to Frobenius distributions and Sato-Tate groups, which uses the orthogonality relations of the irreducible characters of the compact Lie group USp(2g) and its subgroups. To this purpose, I first present a simple method to compute the irreducible characters of USp(2g), then I develop an algorithm based on the Brauer-Klimyk formula. The advantages of this new approach to Sato-Tate groups are examined in detail. The results show that the error grows slowly. I also use the family of genus 3 curves studied in Part 1 as a case study. The analyses and comparisons show that the character theory approach is a more intrinsic and very promising tool for studying Sato-Tate groups
Crook, Deborah. "Polynomial invariants of the Euclidean group action on multiple screws : a thesis submitted to the Victoria University of Wellington in fulfilment of the requirements for the degree of Master of Science in Mathematics /." ResearchArchive@Victoria e-Thesis, 2009. http://hdl.handle.net/10063/1205.
Повний текст джерелаMishchenko, Kateryna. "Numerical Algorithms for Optimization Problems in Genetical Analysis." Doctoral thesis, Västerås : Scool of education, Culture and Communication, Mälardalen University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-650.
Повний текст джерелаMair, Patrick, Kurt Hornik, and Leeuw Jan de. "Isotone Optimization in R: Pool-Adjacent-Violators Algorithm (PAVA) and Active Set Methods." American Statistical Association, 2009. http://epub.wu.ac.at/3993/1/isotone.pdf.
Повний текст джерелаFeng, Tao. "Design and Analysis of Efficient Adaptive Algorithms for Active Control of Vehicle Interior Sound." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1490354549915601.
Повний текст джерелаSchulz, Sergio Luiz. "Metodologia para a alocação ótima discreta de sensores e atuadores piezoelétricos na simulação do controle de vibrações em estruturas de materiais compósitos laminados." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/62047.
Повний текст джерелаThe main objective of vibration control is its reduction or even its minimization by the automatic modification of the structural response. Sometimes this is necessary to increase structural stability and to attain a high mechanical behavior in several areas such as aerospace, civil and mechanical engineering, biotechnology, including macro, micro and nanomechanical scales. An alternative is to use a smart structure, which results of the combinations of integrated sensors and actuators in a mechanical structure and a suitable control method. Development of a computational code to simulate, using finite elements, the active control in smart structures such as slender shells, plates and beams of composite materials with embedded piezoelectric layers acting as actuators and sensors is the main objective of this work. This research is characterized by the use of the GPL-T9 element with three nodes and six mechanical degrees of freedom and one electrical degree of freedom per piezoelectric layer, by the evaluation of two control methods, the Proportional Integral Derivative (PID) and the Linear Quadratic Regulator (LQR), including the Modal LQR, and, finally by the optimization of piezoelectric patches placement using a Genetic Algorithm (GA). Several examples are presented and compared with those obtained by other authors.
Plachkov, Alex. "Soft Data-Augmented Risk Assessment and Automated Course of Action Generation for Maritime Situational Awareness." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35336.
Повний текст джерелаGanti, Mahapatruni Ravi Sastry. "New formulations for active learning." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51801.
Повний текст джерела