Дисертації з теми "Segmented modeling"
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Idbenjra, Khaoula. "Essays on Segmented-Modeling Approaches for Business Analytical Applications." Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILA027.
The increasing complexities of financial decision-making, intensified by recent financial crises, necessitate transparent advanced predictive modeling, especially in the realms of credit scoring and customer retention. This dissertation explores the significant merits of hybrid segmentation-based models, with a pivotal focus on the Logit Leaf Model (LLM), across varied applications: Business-to-Business (B2B) customer retention, credit scoring, and Non-Performing Loan (NPL) management. The exigency for robust, interpretable, and flexible analytical tools has been amplified, especially against the backdrop of modern financial and economic challenges. Thus, this research meticulously interweaves findings from three pivotal studies to explore and critique the functionality, applicability, and merit of the LLM in diverse contexts.The study in chapter 2 highlights LLM's applicability in B2B scenarios, where customer retention becomes crucial. The study shows how the LLM can improve strategies for B2B customer retention by using uplift modeling and providing essential insights to managers through specific, overall, and segment-level visualizations that strengthen managerial decision-making. The second study, presented in chapter 3, explores the field of credit scoring, spotlighting LLM's superior predictive performance and exceptional interpretability, which makes it stand out amidst traditional models like logistic regression and decision trees, and even when compared to advanced models such as neural networks.Chapter 4, introducing the third study, offers a detailed analysis using the Logit Leaf Model (LLM) to demonstrate its capability to predict and comprehend the complexities of Non-Performing Loans (NPLs). This is achieved through a thorough examination of debtor, loan, and macroeconomic features. The model's ability to concurrently provide precise predictions and yield practical insights, when compared with various alternate credit risk models, accentuates its practicality in managing financial risk, especially within retail banking scenarios.Through a thorough exploration and combination of the studies mentioned above, this dissertation highlights the LLM's varied abilities in navigating through different but inherently data-driven fields. It raises discussion on the usefulness of hybrid segmentation-based models in making complex decisions, praising the LLM for its ability to combine predictive power with interpretability and act as a powerful tool across various applications. The dissertation also suggests areas for future research in chapter 5, encouraging further exploration into the scalability, adaptability, and potential improvements of the LLM across various sectors and analytical challenges
Bai, Xiaoyu. "Micromagnetic Modeling of Thin Film Segmented Medium for Microwave-Assisted Magnetic Recording." Research Showcase @ CMU, 2018. http://repository.cmu.edu/dissertations/1131.
Jesuthasan, Nirmalakanth. "Modeling of thermofluid phenomena in segmented network simulations of loop heat pipes." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106276.
L'objectif principal de cette thèse consiste à formuler, mettre en œuvre, tester et démontrer des modèles mathématiques et des méthodes numériques pour réaliser la simulation d'écoulements de fluide et de transfert de chaleur dans des boucles fluides diphasiques [Loop Heat Pipes (LHPs) en anglais], opérant en régime permanent. Un modèle de réseau segmenté thermofluide pour simuler le fonctionnement en régime permanent des LHPs conventionnelles avec des évaporateurs cylindriques et plats est proposé. Dans ce modèle, la ligne de transport de la vapeur, le tuyau du condenseur et la ligne de transport du liquide sont divisés en segments longitudinaux (ou volumes de contrôle). Des formulations quasi-unidimensionnelles, intégrant des corrélations semi-empiriques pour les phénomènes multiphasiques sont utilisées pour assurer la conservation de la masse, de la quantité de mouvement et de l'énergie sur chacun des segments individuels, puis sur l'ensemble du LHP. Les variations des propriétés thermophysiques du fluide en fonction de la température sont prises en compte, ainsi que le changement dans le titre en vapeur, la chute de pression, et le transfert de chaleur dans les régions diphasiques, améliorant ainsi les capacités du modèle proposé par rapport aux modèles précédents de réseaux de LHPs. Le modèle proposé est utilisé pour simuler un LHP pour lequel des mesures expérimentales sont disponibles dans la littérature: les prédictions du modèle proposé sont en très bon accord avec les résultats expérimentaux. Dans les modèles quasi-unidimensionnels précédents de LHPs, la chute de pression pour un débit de vapeur à travers les gorges de l'évaporateur est calculée en utilisant une corrélation faisant intervenir un facteur de friction s'appliquant uniquement dans la région pleinement développé de conduits avec des murs imperméables. Cette approche est inacceptable quand cette baisse de pression devient significative devant la chute de pression globale du LHP. Une corrélation plus précise pour prédire cette chute de pression est alors nécessaire. Pour répondre à ce besoin, une méthode de volumes éléments finis (CVFEM) est proposée pour prédire l'écoulement en trois dimensions du fluide et le transfert de chaleur dans différents conduits à section uniforme régulière et irrégulière. La méthodologie du CVFEM est également adaptée pour formuler une méthode plus simple en volumes finis (FVM). Cette approche est utilisée pour étudier l'écoulement laminaire de fluides newtoniens et le transfert de chaleur dans des cannelures de vapeur à section rectangulaire, pour des conditions typiques de fonctionnement d'un LHP. Les résultats sont utilisés pour élaborer les caractéristiques d'une région pleinement développé (particulière aux LHPs) et de proposer de nouvelles corrélations pour le calcul de la chute de pression globale et des températures de vapeur. Ces corrélations sont incorporées dans le modèle quasi-unidimensionnel pour obtenir un modèle amélioré de réseau segmenté thermofluide pour les LHPs. Les métaux poreux, fabriqués à partir de poudre de métaux sintérisées, ayant une faible porosité (0.30 - 0.50) et un diamètre de pores de petite taille (2.0 à 70 micromètres), sont les matériaux idéals pour la mèche des LHPs. Les paramètres d'entrées des modèles mathématiques de LHPs incluent la porosité, la taille effective maximale des pores, la perméabilité effective et la conductivité thermique effective de la mèche saturée d'un liquide. La détermination de ces propriétés par des expériences simples est réalisée en utilisant un échantillon poreux fritté de poudre de métal en acier inoxydable 316. Enfin, les capacités du modèle améliorée du réseau segmenté thermofluide discuté ci-dessus sont démontrées en l'utilisant pour simuler un LHP opérant en régime permanent avec quatre fluides différents: l'ammoniac, l'eau distillée, l'éthanol et l'isopropanol. Les résultats sont présentés et discutés comparativement.
Ringenberg, Jordan. "Computerized 3D Modeling and Simulations of Patient-Specific Cardiac Anatomy from Segmented MRI." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1406129522.
Roslyakova, Irina [Verfasser], Holger [Gutachter] Dette, and Ingo [Gutachter] Steinbach. "Modeling thermodynamical properties by segmented non-linear regression / Irina Roslyakova ; Gutachter: Holger Dette, Ingo Steinbach." Bochum : Ruhr-Universität Bochum, 2017. http://d-nb.info/1140222953/34.
Zelinski, Michael E. "A segmented aperture space telescope modeling tool and its application to remote sensing as understood through image quality and image utility /." Online version of thesis, 2009. http://hdl.handle.net/1850/11658.
Steinberg, Andreas [Verfasser], Henriette [Akademischer Betreuer] Sudhaus, and Wolfgang [Gutachter] Rabbel. "Improved modeling of segmented earthquake rupture informed by enhanced signal analysis of seismic and geodetic observations / Andreas Steinberg ; Gutachter: Wolfgang Rabbel ; Betreuer: Henriette Sudhaus." Kiel : Universitätsbibliothek Kiel, 2021. http://d-nb.info/1236572122/34.
Rocha, Tassiana Duarte da. "Análise numérica do comportamento de juntas entre aduelas de vigas protendidas." Universidade do Estado do Rio de Janeiro, 2012. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=5616.
Several researchers have studied the behavior and the use of concrete staves, which are segmented beams in structural systems, especially bridges and overpasses, in civil engineering. For this reason, numerous studies have been published in recent years supported by experimental tests and numerical analyzes. The behavior of these beams in contrast to the conventional monolithic beams in different ways because the structure is composed of portions of pre-cast concrete elements which after being placed in situ are prestressed. The prestressing can be adhered or otherwise attached. The main advantage of this system of construction is speed and high quality control, so it is widely used; there is a demand forecast study their actual behavior. In this paper, we present a finite element model to simulate the behavior of composite beams prestressed by adherent with staves. Therefore, the objective of this research is to make a contribution to the study of static structural behavior of beams targeted observing the behavior of joints using a commercial program. For the model are employed standard techniques of discretization via the finite element method (FEM), using the finite element program SAP2000 [90]. The model is made of elements suitable for plaque to represent the actual beam, the prestressing is introduced by means of two-dimensional bar which transfer the stresses along its length and the joints are implemented using contact elements proposed by the program, called Link. The analysis is two dimensional and considers the effects of prestressing losses. This research also aims to study the contact elements especially the characteristics of deformation to this computational tool. The definition of parameters for the model was based on experimental data available in literature. The numerical model was calibrated and compared with experimental results obtained in laboratory trials.
Hartasánchez, Frenk Diego Andrés 1982. "Modeling and simulation of interlocus gene conversion." Doctoral thesis, Universitat Pompeu Fabra, 2016. http://hdl.handle.net/10803/525842.
Duplicated regions of the genome, such as Segmental Duplications (SDs), are a pervasive feature of eukaryotic genomes and have been linked to phenotypic changes. Given their evolutionary relevance, having a neutral model to describe their evolution is essential. In this thesis, I report the development of SeDuS, a forward-in-time computer simulator of SD neutral evolution. Duplications are known to undergo a recombination process, termed interlocus gene conversion (IGC), which is known to affect the patterns of variation and linkage disequilibrium within and between duplicates. Here I describe the effects of overlapping crossover and IGC susceptible regions and of incorporating sequence similarity dependence of IGC. Furthermore, since SDs are potential targets of natural selection, I report potential confounding effects of IGC on test statistics when these are applied to duplications. Finally, I explore the possibility of combining results of different test statistics applied genome-wide to detect the presence of collapsed duplications.
Yeung, Anson Chi-Ming Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Polymer segmented cladding fibres: cross fibre modelling, design, fabrication and experiment." Publisher:University of New South Wales. Electrical Engineering & Telecommunications, 2009. http://handle.unsw.edu.au/1959.4/43656.
Holmes, Wendy Jane. "Modelling segmental variability for automatic speech recognition." Thesis, University College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267859.
Mainka, Julia. "Impédance locale dans une pile à membrane H2/air (PEMFC) : études théoriques et expérimentales." Thesis, Nancy 1, 2011. http://www.theses.fr/2011NAN10042/document.
The aim of this Ph.D thesis is to contribute to a better understanding of the low frequency loop in impedance spectra of H2/air fed PEMFC and to bring information about the main origin(s) of the oxygen transport impedance through the porous media of the cathode via locally resolved EIS. Different expressions of the oxygen transport impedance alternative to the one-dimensional finite Warburg element are proposed. They account for phenomena occurring in the directions perpendicular and parallel to the electrode plane that are not considered usually: convection through the GDL and along the channel, finite proton conduction in the catalyst layer, and oxygen depletion between the cathode inlet and outlet. A special interest is brought to the oxygen concentration oscillations induced by the AC measuring signal that propagate along the gas channel and to their impact on the local impedance downstream. These expressions of the oxygen transport impedance are used in an equivalent electrical circuit modeling the impedance of the whole cell. Experimental results are obtained with instrumented and segmented cells designed and built in our group. Their confrontation with numerical results allows to identify parameters characterizing the physical and electrochemical processes in the MEA
Denoziere, Guilhem. "Numerical Modeling of a Ligamentous Lumbar Motion Segment." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4998.
Rasid, Mohd Azri Hizami. "Contribution to multi-physical studies of small synchronous-reluctance machine for automotive equipment." Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2260/document.
In an on-board automotive environment, machines optimal design requires simultaneous consideration of numerous physical phenomena; both in terms of expected performance or in terms of constraints to be respected. The physics that can be affected includes the electromagnetic / electromechanical performance, thermal behavior and vibro-acoustic behavior. Among a large choice of machine, with the manufacturer cost and manufacturing concern taken en into account, the synchronous reluctance machine with segmented has been found to be particularly interesting for application with severe ambient temperature and encumbrance limitation. This study has therefore as objectives to evaluate the capacity of the synchronous reluctance machine in ail physics mentioned and eventually shows the interaction between these physics, thus performance alteration of the machine in operated in the automobile equipment environment. Multi-physics model were developed and confronted to experimental validations using a prototype machine that was developed for an electrical clutch. Using the validated model, different performance figures of synchronous reluctance machines with different rotor topologies were compared. Resulting from the study, valid electromagnetic, electromechanical, thermal and vibro-acoustic models are now available to be used as tools in future machine design. The synchronous reluctance with segmented rotor prototype machine has been shown to be capable to be used in the electrical clutch application studied in particular. Following performance evaluations in different physics, suggestions of improvements have also been proposed
Reed, Jeremy T. "Acoustic segment modeling and preference ranking for music information retrieval." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37189.
Chang, Jane W. (Jane Wen) 1970. "Near-miss modeling : a segment-based approach to speech recognition." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/46179.
Serridge, Benjamin M. (Benjamin Michael) 1973. "Context-dependent modeling in a segment-based speech recognition system." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43583.
Includes bibliographical references (leaves 78-80).
by Benjamin M. Serridge.
M.Eng.
Sun, Yingcheng. "Topic Modeling and Spam Detection for Short Text Segments in Web Forums." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1575281495398615.
Glisse, Marc. "Combinatoire des droites et segments pour la visibilité 3D." Phd thesis, Université Nancy II, 2007. http://tel.archives-ouvertes.fr/tel-00192337.
Layton, Todd Samuel. "A generalized (k, m)-segment mean algorithm for long term modeling of traversable environments." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/91695.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 75-76).
We present an ecient algorithm for computing semantic environment models and activity patterns in terms of those models from long-term value trajectories defined as sensor data streams. We use an expectation-maximization approach to calculate a locally optimal set of path segments with minimal total error from the given data signal. This process reduces the raw data stream to an approximate semantic representation. The algorithm's speed is greatly improved by the use of lossless coresets during the iterative update step, as they can be calculated in constant amortized time to perform operations with otherwise linear runtimes. We evaluate the algorithm for two types of data, GPS points and video feature vectors, on several data sets collected from robots and human-directed agents. These experiments demonstrate the algorithm's ability to reliably and quickly produce a model which closely ts its input data, at a speed which is empirically no more than linear relative to the size of that data set. We analyze several topological maps and representative feature sets produced from these data sets.
by Todd Samuel Layton.
M. Eng.
Turunc, Cagri. "An Implementation Of Ekf Slam With Planar Segments." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614906/index.pdf.
it is believed that, contribution of adding a direction vector to 3D features is investigated and illustrated via graphs of monte-carlo simulations. At the second part of the work, a scanner sensor system with IR distance finder is designed and constructed. An algorithm was presented to extract planar features from data collected by sensor system. A noise model was proposed for output features of sensor and 4D EKF SLAM algorithm was executed via extracted features of scanner system. By this way, performance of 4D EKF SLAM algorithm is tested with real sensor data and output results are compared with 3D features. So in this work, contribution of using 4D features instead of 3D ones was examined via comparing performance of 3D and 4D algorithms with simulation results and real sensor data.
Turunc, Cagri. "An Implementation Of 3d Slam With Planar Segments." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12614928/index.pdf.
it is believed that, contribution of adding a direction vector to 3D features is investigated and illustrated via graphs of monte-carlo simulations. At the second part of the work, a scanner sensor system with IR distance finder is designed and constructed. An algorithm was presented to extract planar features from data collected by sensor system. A noise model was proposed for output features of sensor and 4D EKF SLAM algorithm was executed via extracted features of scanner system. By this way, performance of 4D EKF SLAM algorithm is tested with real sensor data and output results are compared with 3D features. So in this work, contribution of using 4D features instead of 3D ones was examined via comparing performance of 3D and 4D algorithms with simulation results and real sensor data.
Knecht, Casey Scott. "Crash Prediction Modeling for Curved Segments of Rural Two-Lane Two-Way Highways in Utah." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4352.
Durkin, Jennifer Dowling James. "Development of a geometric modelling approach for human body segment inertial parameter estimation /." *McMaster only, 2003.
Jaitman, Abigail. "Multi-segment foot modelling to enable an understanding of altered gait in diabetes." Thesis, University of Warwick, 2016. http://wrap.warwick.ac.uk/88864/.
Day, Judd S. "Use of a magnetic tracking device for three-dimensional link segment modeling in manual materials handling." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq20623.pdf.
Rastenė, Irma. "Autoregresinio modelio pasikeitusio segmento testavimas ir vertinimas." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110628_134442-76842.
In the doctoral dissertation, we consider problems of testing and estimating changed segment with unknown starting position and duration of epidemic state in the autoregressive first-order model. The proposed tests are based on partial sums of model residuals and model-parameter partial-estimator polygonal line processes. We derive asymptotic results for these processes in Holder spaces. The behavior of test statistics under the null hypothesis of no change and alternative is provided. Empirical power analysis has shown that tests are more powerful when absolute values of model parameter are quite large or autoregressive process changes from a stationary state to a nonstationary one. We prove the consistency of the least square changed-segment estimators and provide their convergence rates.
Ghyoot, Christiaan Jacob. "The modelling of particle build up in shell-and-tube heat exchangers due to process cooling water / Christiaan Jacob Ghyoot." Thesis, North-West University, 2013. http://hdl.handle.net/10394/9511.
Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013
Andersson, Per-Åke. "Multi-year maintenance optimisation for paved public roads - segment based modelling and price-directive decomposition." Doctoral thesis, Linköpings universitet, Optimeringslära, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8907.
The thesis deals with the generation of cost efficient maintenance plans for paved roads, based on database information about the current surface conditions and functional models for costs and state changes, partly developed in cooperation with Vägverket (VV, Swedish Road Administration). The intended use is in a stage of budgeting and planning, before concrete project information is available. Unlike the up to now used models, individual maintenance plans can be formulated for each segment (a homogeneous road section as to the current pavement state and paving history), in continuous state and works spaces. By using Lagrangean relaxation optimisation techniques, the special benefit/cost-ratio constraints that VV puts on each maintenance project can be naturally mastered by dual prices for the budget constraints. The number of segments competing for budget resources is usually large. Data from VV Vägdatabank (SRA Road Database) in county Värmland were used, comprising around 9000 road segments. Due to the large data amount the implemented programs rely on parallel computation. During the thesis work, access to the PC-cluster Monolith at NSC was granted. In order to reduce optimisation run times, model & method development was needed. By aggregating the road segments into road classes, good initial values of the dual prices were achieved. By adding new state dimensions, the use of the Markov property could be motivated. By developing a special residual value routine, the explicitly considered time period could be reduced. At solving the dual subproblem special attention was paid to the discretization effects in the dynamic programming approach. One type of study is on a sub-network, e.g. a road. Validation studies were performed on road 63 in Värmland – with promising but not satisfactory results (see below). A special model for co-ordinated maintenance considers the fine-tuned cost effects of simultaneous maintenance of contiguous road segments. The other main type of study is for a whole network. Several method types have been applied, both for solving the relaxed optimisation problems and for generating maintenance plans that fit to the budgets. For a decent discretization, the run time for the whole Värmland network is less than 80 CPU-hrs.A posterior primal heuristics reduces the demands for parallel processing to a small PC-cluster.The thesis further studies the effects of redistributing budget means, as well as turning to a transparent stochastic model – both showing modest deviations from the basic model. Optimisation results for Värmland indicate budget levels around 40% of the actual Värmland budget as sufficient. However, important cost triggers are missing in this first model round, e.g., certain functional performance (safety), all environmental performance (noise etc.) and structural performance (e.g. bearing capacity, only modelled by an age measure). For increased credibility of PMS in general and optimisation in particular, the discrepancies should be further analysed and lead to improvements as to condition monitoring, state effect & cost modelling and mathematical modelling & implementation.
Manos, Alexandros Sterios. "A study on out-of-vocabulary word modelling for a segment-based keyword spotting system." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/39394.
Includes bibliographical references (leaves 93-95).
by Alexandros Sterios Manos.
M.S.
Neto, Leoncio Claro de Barros. "Modelagem em geometria digital aprimorada por técnicas adaptativas de segmentos de retas." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/3/3141/tde-11082011-135522/.
For the representation of digital straight lines, digitized straight line segments and arcs, each of the available research approaches has its advantages and suitable applications. However, taking into account the complexities of real-world scenarios, the use of these representations is not so popular in situations that require flexible models or involving spurious interferences. Adaptive technologies are computer science formalisms able to change their behavior dynamically, without the interference of external agents, in response to incoming stimuli. By being able to respond to changing environmental conditions, adaptive devices naturally tend to have the required flexibility to work in dynamic scenarios. Thus, the purpose of this study is to investigate an alternative based on adaptive finite automaton through the device called adaptive digitized straight line segment, incorporating the expressive power to represent parameters of these segments. Among these parameters, emphasis is given to the ability to represent tolerances, scalability or errors caused by deviations in angle or length of the mentioned segments, resulting in more flexible structures. Whereas syntactic methods are structural, adaptive digitized straight line segments are modeled by sets of rules, starting from primitives, conceiving the corresponding adaptive functions to amend the set of states and transition rules. Later, more elaborate structures are designed related to digital arcs the corresponding strings of which stimulate, in just a single step, adaptive finite automata that implement adaptive digitized straight line segments. The implementations use a simulator for editing the files that compose the automata. Consequently, the proposed method reveals to be a simple and intuitive alternative capable of learning, besides being computationally powerful.
Rastenė, Irma. "Testing and estimating changed segment in autoregressive model." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110628_134429-88914.
Disertacijoje nagrinėjamas pirmos eilės autoregresinio modelio pasikeitusio segmento testavimo ir vertinimo uždavinys. Aprašomo modelio epideminio pasikeitimo pradžia ir ilgis nėra žinomi. Pasiūlyti kriterijai pasikeitusio segmento testavimui, kurie pagrįsti modelio paklaidų įvertinių dalinių sumų ir modelio parametro dalinių įvertinių laužčių procesais. Šiems procesams gautos ribinės teoremos Hiolderio erdvėse. Nurodomas testų statistikų ribinis elgesys esant teisingai nulinei ir alternatyviajai hipotezėms. Iš empirinio kriterijų galios tyrimo rezultatų matyti, kad pasiūlytų testų galia didžiausia aptinkant pasikeitimus iš stacionarios būklės į nestacionarią arba esant artimoms vienetui modelio parametro reikšmėms. Taip pat įrodoma, kad mažiausių kvadratų metodu gauti pasikeitusio segmento pradžios ir ilgio įverčiai bei autoregresinio modelio su pasikeitusiu segmentu parametrų įverčiai yra suderintieji bei pateikiamas jų konvergavimo greitis.
Nanavati, Hemant. "Molecular modeling of the elastic and photoelastic properties of crosslinked polymer networks: a statistical segment approach / by Hemant Nanavati." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/8227.
Jablonski, Sophie Marie-Odile. "Assessment of bioenergy heating potential in the UK and in Poland using market segments analysis and MARKAL modelling." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511992.
Peral, Millán Mireia. "Dynamics of subduction systems with opposite polarity in adjacent segments: application to the Westernmost Mediterranean." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/672453.
El objetivo de esta tesis consiste en estudiar la dinámica de sistemas de doble subducción con polaridad opuesta en segmentos adyacentes. La ausencia de estudios previos sobre el análisis de la evolución geodinámica de estos sistemas ha definido la estrategia de investigación del presente trabajo. En consecuencia, esta tesis consta de tres partes diferenciadas que combinan tanto experimentos análogos como modelos numéricos de sistemas de doble subducción y su posterior aplicación a la región del Mediterráneo occidental, donde se ha propuesto un sistema de doble subducción con polaridad opuesta en segmentos adyacentes para explicar su formación y evolución. Parte 1. Experimentos análogos de sistemas de subducción con polaridad opuesta en segmentos adyacentes La primera parte de esta tesis consiste en analizar la dinámica de los sistemas de doble subducción con polaridad opuesta en segmentos litosféricos adyacentes mediante experimentos análogos. Estos experimentos se han llevado a cabo en el Laboratorio de Tectónica Experimental en la Universidad de Roma Tre durante una estancia de dos meses en Roma (Italia) bajo la supervisión de la Prof. Dr. Francesca Funiciello y el Prof. Dr. Claudio Faccenna. Se han diseñado un total de dieciocho experimentos, incluyendo cuatro modelos de referencia de subducción simple (una placa). Estos experimentos consisten en una o dos placas elaboradas con silicona representando la litosfera y un tanque lleno de jarabe de glucosa representando el manto. Las placas se fijan en su borde posterior para imponer un comportamiento de retroceso de las fosas de subducción (trench rollback) y la subducción se inicia hundiendo manualmente el borde delantero de la placa. Se han diseñado diferentes configuraciones para probar la influencia en la evolución del sistema de la anchura de las placas y la separación inicial entre ellas. Los resultados muestran que el flujo del manto inducido por ambas placas es asimétrico con respecto al eje de cada placa. Esto provoca una fusión progresiva de las celdas toroidales impidiendo una fase de estabilización del proceso de subducción y generando una fuerza de arrastre neta que tiende a separar las placas. Las velocidades de retroceso de las fosas (velocidad de subducción) dependen de la posición relativa de éstas, aumentando cuando las fosas se acercan entre sí y disminuyendo cuando éstas se separan después de su alineación. Parte 2. Reproducción de experimentos análogos de sistemas de subducción mediante modelos numéricos En segundo lugar, se han realizado una serie de modelos numéricos, basados en los experimentos análogos realizados en la primera parte con el objetivo de comparar y complementar los resultados anteriores así como cuantificar los parámetros físicos más relevantes que caracterizan a un sistema de doble subducción con polaridad opuesta. En total, se han realizado alrededor de treinta y cinco modelos numéricos, además de las pruebas preliminares, aunque en esta tesis sólo se presentan quince de ellos mostrando los resultados más relevantes. Los modelos numéricos se han calculado principalmente en los supercomputadores MARENOSTRUM 4 (Centro de Supercomputación de Barcelona, España) y BRUTUS (Instituto Federal Suizo de Tecnología, Suiza), con un tiempo de cálculo promedio de 3 semanas por modelo. La configuración numérica 3D se elige con parámetros de geometría, dimensiones y materiales similares a los modelos análogos de subducción realizados anteriormente. Éstos consisten en una o dos placas viscosas que subducen en el manto superior en direcciones opuestas. Las placas están fijadas en su borde posterior imponiendo un comportamiento de retroceso de la fosa durante la subducción. La subducción se produce debido a la diferencia de densidades entre la placa y el manto a partir de una pequeña subducción impuesta inicialmente. En primer lugar, se estudian el tamaño del dominio computacional, las condiciones de contorno, la reología y el grosor de las placas para encontrar el modelo numérico que mejor representa el experimento análogo. En segundo lugar, se estudian los parámetros más relevantes que controlan el proceso de doble subducción con polaridad opuesta mediante técnicas numéricas. Los resultados muestran que las condiciones de contorno del modelo numérico más adecuadas para reproducir los experimentos análogos son el deslizamiento libre en las paredes laterales del dominio computacional y el deslizamiento nulo en la pared inferior. Las condiciones de contorno laterales sólo afectan a la evolución del sistema a distancias muy pequeñas, lo que permite una reducción del tamaño del dominio computacional en relación con el modelo análogo aumentando la resolución numérica y disminuyendo el tiempo de cálculo. De manera complementaria a los resultados observados en los experimentos análogos, los resultados numéricos muestran que el flujo inducido del manto genera un acoplamiento en la tensión entre las placas adyacentes, ralentizando el proceso de subducción. Así mismo, se produce un movimiento lateral entre las placas en superficie y una deformación asimétrica de las porciones subducidas (slabs) y de las fosas. Parte 3. Las cuencas de Alborán y Argelia (Mediterráneo occidental). Un caso de estudio de doble subducción con polaridad opuesta en segmentos adyacentes Finalmente, se ha realizado un modelo numérico 3D de doble subducción con polaridad opuesta en segmentos litosféricos adyacentes simulando la configuración tectónica del Mediterráneo occidental. El modelo numérico reproduce la evolución del segmento de placa de Alborán-Tethys estudiando la influencia del segmento de placa adyacente de Argelia- Tethys. Se han realizado alrededor de cuarenta modelos numéricos variando parámetros físicos y geométricos, incluyendo los modelos numéricos preliminares. En esta tesis sólo se presentan el modelo final de doble subducción con polaridad opuesta y de subducción simple. Los modelos numéricos se han calculado en el supercomputador MARENOSTRUM 4 (Centro de Supercomputación de Barcelona, España) con un tiempo de cálculo promedio de 4 semanas por modelo. El modelo consta de dos segmentos de placa oceánica con una reología viscoplástica que subducen en direcciones opuestas en el manto superior viscoso. El modelo se inicia hace 35 millones de años. En la región actual de la cuenca del Alborán, el segmento de placa de Alborán-Tethys subduce hacia el sureste con el borde posterior fijado al margen ibérico. Se incluye un segmento de placa continental africana en el lado oeste de esta placa. En la región actual de la cuenca argelina, el segmento de placa de Tell-Kabylies subduce hacia el noroeste y el borde posterior se fija al margen africano. El estado inicial del modelo considera la convergencia entre África e Iberia desde el temprano Cretácico hasta el tardío Eoceno imponiendo una subducción inicial de los segmentos de placa de 150 km. El posterior proceso de subducción es impulsado por la inestabilidad de Rayleigh-Taylor. Además, se ha realizado un modelo de referencia de placa simple que incluye sólo el segmento de Alborán-Tethys para estudiar la influencia del segmento adyacente subduciendo en dirección opuesta. Los resultados muestran que la curvatura progresiva de la placa de Alborán-Tethys se debe a la falta de una zona de transformación en su conexión con el océano Atlántico al oeste y la gran segmentación del margen africano. Esto produce unas velocidades de retroceso de la fosa mayores en el lado este de la placa de Alborán-Tethys que en el lado occidental, donde una zona de transformación la separa del segmento de Argelia-Tethys. El cálculo de las velocidades de retroceso de las fosas de ambos segmentos de placa concluyen que la apertura de la cuenca de Alborán se produjo aproximadamente hace 22 millones de años. La influencia del segmento argelino adyacente genera un patrón de flujo asimétrico alrededor de ambas fosas que ralentiza el proceso de subducción general del segmento de la placa de Alborán- Tethys.
Zhan, Yijian [Verfasser], Günther [Gutachter] Meschke, and Peter [Gutachter] Mark. "Multilevel modeling of fiber-reinforced concrete and application to numerical simulations of tunnel lining segments / Yijian Zhan ; Gutachter: Günther Meschke, Peter Mark." Bochum : Ruhr-Universität Bochum, 2016. http://d-nb.info/112190954X/34.
Markwardt, Jutta, Günther Pfeifer, Uwe Eckelt, and Bernd Reitemeier. "Analysis of Complications after Reconstruction of Bone Defects Involving Complete Mandibular Resection Using Finite Element Modelling." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-134947.
Hintergrund: In einer retrospektiven Studie wurden Risikofaktoren für Komplikationen nach Überbrückung von Unterkieferdefekten mit Rekonstruktionsplatten geprüft. Insbesondere die Lockerungsvorgänge des Schrauben- Platten-Unterkiefer-Verbundes sollten mit einer Finite- Elemente-Modellierung analysiert werden, um in Zukunft eine Reduzierung der Plattenkomplikationen erreichen zu können. Patienten und Methoden: Es wurden 60 Patienten untersucht, welche im Zeitraum von 10 Jahren im Rahmen von Tumoroperationen mit Rekonstruktionsplatten versorgt wurden. Das Problem der Lockerung der Plattenschrauben wurde zusätzlich mittels einer Finite-Elemente-Studie überprüft und ein Modell für den Lockerungsvorgang erarbeitet. Ergebnisse: Die Nachuntersuchungen ergaben, dass bei 26 Patienten die Platte wegen Komplikationen vorzeitig entfernt werden musste. Die Komplikationen traten als orale und extraorale Plattenfreilage, als Schraubenlockerung ohne oder mit Plattendislokationen und als Plattenbrüche auf. Dabei konnte festgestellt werden, dass bestehende Stützzonen des körpereigenen Restgebisses, die Größe des Unterkieferdefektes und dessen Mittellinienüberschreitung Risikofaktoren für Plattenkomplikationen darstellen. Anhand der Finite-Elemente-Modellierung wurde eine veränderte Schraubenanordnung abgeleitet. Daraus resultiert eine neue Form der Resektionsplatte. Schlussfolgerungen: Durch die Verschiebung der Schraubenlöcher aus der Längsachse der Platte kann der Übergang von der Zugbelastung zur Drehmomentbelastung der Schrauben im Schrauben-Platten-Knochen-Verbund der Platte minimiert werden. Dadurch werden Schraubenlockerungen als Komplikationen wesentlich seltener auftreten
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
Levendoglu, Mert. "Probabilistic Seismic Hazard Assessment Of Ilgaz - Abant Segments Of North Anatolian Fault Using Improved Seismic Source Models." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615430/index.pdf.
lerce et al., 2013) prediction models are employed for the first time on NAF system. The results of the study is presented in terms of hazard curves, deaggregation of the hazard and uniform hazard spectrum for four main locations in the region to provide basis for evaluation of the seismic design of special structures in the area. Hazard maps of the region for rock site conditions and for the proposed site characterization model are provided to allow the user perform site-specific hazard assessment for local site conditions and develop site-specific design spectrum. The results of the study will be useful to manage the future seismic hazard in the region.
Markwardt, Jutta, Günther Pfeifer, Uwe Eckelt, and Bernd Reitemeier. "Analysis of Complications after Reconstruction of Bone Defects Involving Complete Mandibular Resection Using Finite Element Modelling." Karger, 2007. https://tud.qucosa.de/id/qucosa%3A27607.
Hintergrund: In einer retrospektiven Studie wurden Risikofaktoren für Komplikationen nach Überbrückung von Unterkieferdefekten mit Rekonstruktionsplatten geprüft. Insbesondere die Lockerungsvorgänge des Schrauben- Platten-Unterkiefer-Verbundes sollten mit einer Finite- Elemente-Modellierung analysiert werden, um in Zukunft eine Reduzierung der Plattenkomplikationen erreichen zu können. Patienten und Methoden: Es wurden 60 Patienten untersucht, welche im Zeitraum von 10 Jahren im Rahmen von Tumoroperationen mit Rekonstruktionsplatten versorgt wurden. Das Problem der Lockerung der Plattenschrauben wurde zusätzlich mittels einer Finite-Elemente-Studie überprüft und ein Modell für den Lockerungsvorgang erarbeitet. Ergebnisse: Die Nachuntersuchungen ergaben, dass bei 26 Patienten die Platte wegen Komplikationen vorzeitig entfernt werden musste. Die Komplikationen traten als orale und extraorale Plattenfreilage, als Schraubenlockerung ohne oder mit Plattendislokationen und als Plattenbrüche auf. Dabei konnte festgestellt werden, dass bestehende Stützzonen des körpereigenen Restgebisses, die Größe des Unterkieferdefektes und dessen Mittellinienüberschreitung Risikofaktoren für Plattenkomplikationen darstellen. Anhand der Finite-Elemente-Modellierung wurde eine veränderte Schraubenanordnung abgeleitet. Daraus resultiert eine neue Form der Resektionsplatte. Schlussfolgerungen: Durch die Verschiebung der Schraubenlöcher aus der Längsachse der Platte kann der Übergang von der Zugbelastung zur Drehmomentbelastung der Schrauben im Schrauben-Platten-Knochen-Verbund der Platte minimiert werden. Dadurch werden Schraubenlockerungen als Komplikationen wesentlich seltener auftreten.
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
Láštic, Daniel. "Deformačně-napěťová analýza elastomerových komponent flexibilní spojky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401521.
Filbois, Alain. "Contributions à la modélisation automatique d'objets polyédriques 3D : extraction des primitives 3D, facettes et segments." Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL075N.
Cambazoglu, Selim. "Preparation Of A Source Model For The Eastern Marmara Region Along The North Anatolian Fault Segments And Probabilistic Seismic Hazard Assessment Of Duzce Province." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614167/index.pdf.
zce are the most recent devastating earthquakes. The study area lies in the Eastern Marmara Region and is bounded by the 28.55-33.75 E and 40.00-41.20 N, latitude and longitude coordinates, respectively. There are numerous studies conducted in the study area in terms of active tectonics and seismicity, however studies are scale dependent. Therefore, a comprehensive literature survey regarding active tectonics of the region was conducted and these previous studies were combined with the lineaments extracted from 10 ASTER images via principle component analysis manual extraction method. Therefore, a line seismic source model for the Eastern Marmara region was compiled mainly based on major seismic events of instrumental period. The seismicity of these line segments were compared with the instrumental period earthquake catalogue compiled by Kandilli Observatory and Earthquake Research Institute with a homogeneous magnitude scale between 1900 and 2005. Secondary event and completeness of this catalogue was checked. The final catalogue was matched with the compiled seismic source for historical seismicity and source-scenario-segment-weight relationships were developed. This developed seismic source model was tested by a probabilistic seismic hazard assessment for Dü
zce city center by utilizing four different ground motion prediction equations. It was observed that Gutenberg-Richter seismicity parameter &lsquo
b&rsquo
does not have significant effect over the model, however change in the segmentation model have a low but certain influence.
REIS, Paulo Francisco de Oliveira. "Análise numérica da influência dos segmentos grauteados na interação entre paredes de alvenaria estrutural com blocos de concreto." Universidade Federal de Goiás, 2010. http://repositorio.bc.ufg.br/tede/handle/tde/1358.
Structural masonry is one of the oldest building systems used by man. With technological advance, its use has become more and more frequent for providing rationality and economy to the building. For that reason, the research centers have tried to get to know it more precisely, especially in Brazil, where the system differs from other countries, prevailing the use of not armed or partially armed masonry. The studies conducted aim to know, primarily, the materials used and the analysis of their structural behavior. Even though, there are still masonry structural aspects that haven t been totally clarified. Based on that principle, the purpose of this work was to accomplish an investigation about the influence of grouting segments in the interaction between walls, with the utilization of isolated panels of three, five and seven walls and a multiple pavement structure, developed by computational modeling in finite elements. For the analysis of the results, check the profile of the distribution of normal vertical tensions and the absorption of applied loading. In this way, it is realizable that in some cases the grout causes significant interference, as in the holes of the bricks, while in others, its participation is almost despicable. An example is the grouting of the braces.
A alvenaria estrutural é um dos sistemas construtivos mais antigos usado pelo homem. Com o avanço tecnológico, o seu uso passou a ser cada vez maior por proporcionar racionalidade e economia para a construção. Por isso, os centros de pesquisas têm buscado conhecê-la de maneira precisa, principalmente no Brasil, onde o sistema utilizado difere de outros países, prevalecendo o uso da alvenaria não armada ou parcialmente armada. Os estudos feitos visam conhecer, primordialmente, os materiais empregados e a avaliação do seu comportamento estrutural. Mesmo assim, ainda há aspectos estruturais da alvenaria que ainda não foram totalmente esclarecidos. A partir deste princípio, a proposta do trabalho foi realizar uma investigação sobre a influência de segmentos grauteados na interação entre paredes, com a utilização de painéis isolados de três, cinco e sete paredes e uma estrutura de múltiplos pavimentos, desenvolvido por modelagem computacional em elementos finitos. Para análise dos resultados, avaliou-se o perfil da distribuição de tensões verticais normais e absorção do carregamento aplicado, que é transferido às paredes. Nesse sentido, percebe-se que em alguns casos o graute causa interferência significativa, como nos furos dos blocos, enquanto que em outros, a sua participação é praticamente desprezível. Exemplo disso são os grauteamentos das cintas.
Mocrosky, Jeferson Ferreira. "Um estudo sobre a aplicação do padrão BPMN (Business process modeland notation) para a modelagem do processo de desenvolvimento de produtos numa empresa de pequeno porte do segmento metal-mecânico." Universidade Tecnológica Federal do Paraná, 2012. http://repositorio.utfpr.edu.br/jspui/handle/1/721.
Modeling the business process and an approach of the 1990s to improve the performance of organizations, this currently returns as a strong contributor to the improvement of performance of organizations Packing Company, in the region west of Santa Catarina State. Modeling the PDP uses the standard Business Process Model and Notation (BPMN) supported by the application Intalio BPMS. The objective of the research and evaluate the modeling with BPMN for the formalization of the development process of products and how to deal with the complexities and intrinsic interactions of this process, in small companies of mechanical manufacturing. The modeling with BPMN and structured in evaluation of PDP a company selected and comments on the site of the work, the execution of the process. The methodology adopted for the development of modeling PDP the company considered the following aspects: (i) study of a company; (ii) informational modeling; (iii) the automation model and implementation; (iv) implementation of the model of the PDP in the company. Also presented are the characteristics of Unified Model of Rozenfeld et al. (2006), used as a reference to systematize the modeling of the Products Development Process of the company, through evaluation of the process of the company. A brief description and made to have the characteristics of the major standards used in the modeling of business processes, including the main computational applications used to support the standards of modeling. The results were divided into two parts, in abstract models static and dynamic. The abstract model has static informational character, presenting richness of detail, in the form of a detailed map of the process. For automation, this static model was unfolded in two other abstract models, which are configured to become dynamic, aiming at the implementation and execution in order to meet satisfactorily the reality of the implementation of the process in the company. The first abstract model dynamic implemented and executed defines the product and finishes with the customer's decision on the budget requested the sales of the company. The second abstract model dynamic starts with the approval of the budget by the customer, initiated the activities of project informational and ends with the release to production. This approach aims to minimize the complexities of modeling the process and the specific peculiarities of the company. Modeling the PDP with the reference model and the application of standard BPMN supported by Intalio BPMS allowed report best practices, lessons learned, difficulties and facilities found. In addition, the PDP formalized by modeling with BPMN and Intalio BPMS provided significant changes in the implementation of the current process, contributing to greater integration between the participants.
Amara, Mounir. "Segmentation de tracés manuscrits. Application à l'extraction de primitives." Rouen, 1998. http://www.theses.fr/1998ROUES001.
Bureš, David. "Nepostavené Brno Historie a perspektivy nedokončených urbanistických záměrů v městě Brně." Doctoral thesis, Vysoké učení technické v Brně. Fakulta architektury, 2015. http://www.nusl.cz/ntk/nusl-233271.
Solatges, Thomas. "Modélisation, conception et commande de robots manipulateurs flexibles. Application au lancement et à la récupération de drones à voilure fixe depuis un navire faisant route." Thesis, Toulouse, ISAE, 2018. http://www.theses.fr/2018ESAE0012/document.
Robot manipulators are generally stiff machines, designed in a way that flexibility does not affecttheir movements. Indeed, significant flexibility introduces additional degrees of freedom witha complex behavior. However, reducing the mass of a system allows for costs, performance, andsafety improvements. In order to allow those benefits despite important flexibility, this thesis focuseson modeling, design and control of flexible robot manipulators. It is motivated by the YAKAproject, which aims at developing a robot to launch and recover fixed wing UAVs from a movingship. It implies reaching very high dynamics on a large workspace, way beyond the specificationsof common rigid robots. The proposed tools for modeling, design and control allow for taking intoaccount both joint and link flexibility, for any number of degrees of freedom and flexible links.The elastodynamic model is obtained with Lagrange principle, each flexible link being representedwith one ormany Euler-Bernouilli beams. The proposed control scheme uses a nonlinear rigiddynamic inversion and extends classical Input Shaping techniques to flexible robot manipulators.The proposed design tools allow for performance prediction of the system including its actuatorsand controllers thanks to a realistic simulation. Experiments conducted with the YAKA robot validatedthe proposed approach. The results of the YAKA project confirmed the feasibility of usinga large scale, highly dynamic flexible robot in an industrial context, in particular for UAVs launchand recovery operations from amoving ship
Laroum, Sami. "Prédiction de la localisation des protéines membranaires : méthodes méta-heuristiques pour la détermination du potentiel d'insertion des acides aminés." Phd thesis, Université d'Angers, 2011. http://tel.archives-ouvertes.fr/tel-01064309.
Laroum, Sami. "Prédiction de la localisation des protéines membranaires : méthodes méta-heuristiques pour la détermination du potentiel d'insertion des acides aminés." Phd thesis, Angers, 2011. https://theses.hal.science/tel-01064309.
In this work, we are interested in the localization of proteins transported towards the endoplasmic reticulum membrane, and more specifically to the recognition of transmembrane segments and signal peptides. By using the last knowledges acquired on the mechanisms of insertion of a segment in the membrane, we propose a discrimination method of these two types of sequences based on the potential of insertion of each amino acid in the membrane. This leads to search for each amino acid a curve giving its potential of insertion according to its place in a window corresponding to the thickness of the membrane. Our goal is to determine "in silico" a curve for each amino acid to obtain the best performances for our method of classification. The optimization, on data sets constructed from data banks of proteins, of the curves is a difficult problem that we address through the meta-heuristic methods. We first present a local search algorithm for learning a set of curves. Its assessment on the different data sets shows good classification results. However, we notice a difficulty in adjusting the curves of certain amino acids. The restriction of the search space with relevant information on amino acids and the introduction of multiple neighborhood allow us to improve the performances of our method and at the same time to stabilize the learnt curves. We also developed a genetic algorithm to explore in a more diversified way the space of search for this problem
España, Boquera Salvador. "Contributions to the joint segmentation and classification of sequences (My two cents on decoding and handwriting recognition)." Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/62215.
[ES] Este trabajo se centra en problemas (como reconocimiento automático del habla (ASR) o de escritura manuscrita (HTR)) que cumplen: 1) pueden representarse (quizás aproximadamente) en términos de secuencias unidimensionales, 2) su resolución implica descomponer la secuencia en segmentos que se pueden clasificar en un conjunto finito de unidades. Las tareas de segmentación y de clasificación necesarias están tan intrínsecamente interrelacionadas ("paradoja de Sayre") que deben realizarse conjuntamente. Nos hemos inspirado en lo que algunos autores denominan "La trilogía exitosa", refereido a la sinergia obtenida cuando se tiene: - un buen formalismo, que dé lugar a buenos algoritmos; - un diseño e implementación ingeniosos y eficientes, que saquen provecho de las características del hardware; - no descuidar el "saber hacer" de la tarea, un buen preproceso y el ajuste adecuado de los diversos parámetros. Describimos y estudiamos "modelos generativos en dos etapas" sin reordenamientos (TSGMs), que incluyen no sólo los modelos ocultos de Markov (HMM), sino también modelos segmentales (SMs). Se puede obtener un decodificador de "dos pasos" considerando a la inversa un TSGM introduciendo no determinismo: 1) se genera un grafo acíclico dirigido (DAG) y 2) se utiliza conjuntamente con un modelo de lenguaje (LM). El decodificador de "un paso" es un caso particular. Se formaliza el proceso de decodificación con ecuaciones de lenguajes y semianillos, se propone el uso de redes de transición recurrente (RTNs) como forma normal de gramáticas de contexto libre (CFGs) y se utiliza el paradigma de análisis por composición de manera que el análisis de CFGs resulta una extensión del análisis de FSA. Se proponen algoritmos de composición de transductores que permite el uso de RTNs y que no necesita recurrir a composición de filtros incluso en presencia de transiciones nulas y semianillos no idempotentes. Se propone una extensa revisión de LMs y algunas contribuciones relacionadas con su interfaz, con su representación y con la evaluación de LMs basados en redes neuronales (NNLMs). Se ha realizado una revisión de SMs que incluye SMs basados en combinación de modelos generativos y discriminativos, así como un esquema general de tipos de emisión de tramas y de SMs. Se proponen versiones especializadas del algoritmo de Viterbi para modelos de léxico y que manipulan estados activos sin recurrir a estructuras de tipo diccionario, sacando provecho de la caché. Se ha propuesto una arquitectura "dataflow" para obtener reconocedores a partir de un pequeño conjunto de piezas básicas con un protocolo de serialización de DAGs. Describimos generadores de DAGs que pueden tener en cuenta restricciones sobre la segmentación, utilizar modelos segmentales no limitados a HMMs, hacer uso de los decodificadores especializados propuestos en este trabajo y utilizar un transductor de control que permite el uso de unidades dependientes del contexto. Los decodificadores de DAGs hacen uso de un interfaz bastante general de LMs que ha sido extendido para permitir el uso de RTNs. Se proponen también mejoras para reconocedores "un paso" basados en algoritmos especializados para léxicos y en la interfaz de LMs en modo "bunch", así como su paralelización. La parte experimental está centrada en HTR en diversas modalidades de adquisición (offline, bimodal). Hemos propuesto técnicas novedosas para el preproceso de escritura que evita el uso de heurísticos geométricos. En su lugar, utiliza redes neuronales. Se ha probado con HMMs hibridados con redes neuronales consiguiendo, para la base de datos IAM, algunos de los mejores resultados publicados. También podemos mencionar el uso de información de sobre-segmentación, aproximaciones sin restricción de un léxico, experimentos con datos bimodales o la combinación de HMMs híbridos con reconocedores de tipo holístico.
[CAT] Aquest treball es centra en problemes (com el reconeiximent automàtic de la parla (ASR) o de l'escriptura manuscrita (HTR)) on: 1) les dades es poden representar (almenys aproximadament) mitjançant seqüències unidimensionals, 2) cal descompondre la seqüència en segments que poden pertanyer a un nombre finit de tipus. Sovint, ambdues tasques es relacionen de manera tan estreta que resulta impossible separar-les ("paradoxa de Sayre") i s'han de realitzar de manera conjunta. Ens hem inspirat pel que alguns autors anomenen "trilogia exitosa", referit a la sinèrgia obtinguda quan prenim en compte: - un bon formalisme, que done lloc a bons algorismes; - un diseny i una implementació eficients, amb ingeni, que facen bon us de les particularitats del maquinari; - no perdre de vista el "saber fer", emprar un preprocés adequat i fer bon us dels diversos paràmetres. Descrivim i estudiem "models generatiu amb dues etapes" sense reordenaments (TSGMs), que inclouen no sols inclouen els models ocults de Markov (HMM), sinò també models segmentals (SM). Es pot obtindre un decodificador "en dues etapes" considerant a l'inrevés un TSGM introduint no determinisme: 1) es genera un graf acíclic dirigit (DAG) que 2) és emprat conjuntament amb un model de llenguatge (LM). El decodificador "d'un pas" en és un cas particular. Descrivim i formalitzem del procés de decodificació basada en equacions de llenguatges i en semianells. Proposem emprar xarxes de transició recurrent (RTNs) com forma normal de gramàtiques incontextuals (CFGs) i s'empra el paradigma d'anàlisi sintàctic mitjançant composició de manera que l'anàlisi de CFGs resulta una lleugera extensió de l'anàlisi de FSA. Es proposen algorismes de composició de transductors que poden emprar RTNs i que no necessiten recorrer a la composició amb filtres fins i tot amb transicions nul.les i semianells no idempotents. Es proposa una extensa revisió de LMs i algunes contribucions relacionades amb la seva interfície, amb la seva representació i amb l'avaluació de LMs basats en xarxes neuronals (NNLMs). S'ha realitzat una revisió de SMs que inclou SMs basats en la combinació de models generatius i discriminatius, així com un esquema general de tipus d'emissió de trames i altre de SMs. Es proposen versions especialitzades de l'algorisme de Viterbi per a models de lèxic que permeten emprar estats actius sense haver de recórrer a estructures de dades de tipus diccionari, i que trauen profit de la caché. S'ha proposat una arquitectura de flux de dades o "dataflow" per obtindre diversos reconeixedors a partir d'un xicotet conjunt de peces amb un protocol de serialització de DAGs. Descrivim generadors de DAGs capaços de tindre en compte restriccions sobre la segmentació, emprar models segmentals no limitats a HMMs, fer us dels decodificadors especialitzats proposats en aquest treball i emprar un transductor de control que permet emprar unitats dependents del contexte. Els decodificadors de DAGs fan us d'una interfície de LMs prou general que ha segut extesa per permetre l'ús de RTNs. Es proposen millores per a reconeixedors de tipus "un pas" basats en els algorismes especialitzats per a lèxics i en la interfície de LMs en mode "bunch", així com la seua paral.lelització. La part experimental està centrada en el reconeiximent d'escriptura en diverses modalitats d'adquisició (offline, bimodal). Proposem un preprocés d'escriptura manuscrita evitant l'us d'heurístics geomètrics, en el seu lloc emprem xarxes neuronals. S'han emprat HMMs hibridats amb xarxes neuronals aconseguint, per a la base de dades IAM, alguns dels millors resultats publicats. També podem mencionar l'ús d'informació de sobre-segmentació, aproximacions sense restricció a un lèxic, experiments amb dades bimodals o la combinació de HMMs híbrids amb classificadors holístics.
España Boquera, S. (2016). Contributions to the joint segmentation and classification of sequences (My two cents on decoding and handwriting recognition) [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62215
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