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Pasquer, Caroline. "Garder la trace, mettre de l'ordre et relier les points : modéliser la variation et l'ambiguïté des expressions polylexicales." Thesis, Tours, 2019. http://www.theses.fr/2019TOUR4017.
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L’identification automatique d’expressions polylexicales (EP) est un pré-requis pour de nombreuses applications de traitement automatique des langues. Cette tâche représente un défi car les EP, et en particulier les verbales (EPV) telles que 'casser sa pipe' (signifiant 'mourir'), ont des formes de surface très variables ('cassera-t-il un jour sa pipe ?'). Cependant, comparée à des constructions libres, cette variabilité est généralement plus restreinte (p. ex. certains noms non modifiables par un adjectif), d’où des profils de variabilité distincts. On se penche ici sur un sous-problème de l’identification d’EPV, à savoir l’identification d’occurrences d’EPV vues dans d’autres contextes, quelque soit leur forme de surface, ce qui nécessite de prendre en compte l’ambiguïté pour éviter des lectures littérales ('casser sa vieille pipe') ou des co-occurrences fortuites ('casser le tuyau de sa pipe'). On considère pour cela deux approches : la première se fonde sur une mesure de la variabilité des EPV indépendante de la langue. La seconde consiste à modéliser le problème comme une tâche de classification d’après des traits pertinents pour la variabilité morpho-syntaxique des EPV, ce qui nous a conduit à développer un système (VarIDE), qui a participé à la compétition PARSEME d’identification automatique d’EPV en 2018Automatic identification of multiword expressions (MWEs) is a pre-requisite for many natural language processing applications. This task is challenging because MWEs, especially verbal ones (VMWEs) like to kick the bucket (which means to die), exhibit surface variability (no buckets were kicked ). However, compared with regular constructions, this variability is usually more restricted (e.g. some nouns cannot be modified by an adjective), hence various variability profiles. We address here a subproblem of VMWE identification, namely the identification of occurrences of VMWEs previously seen in corpora, whatever their surface form, which requires to take ambiguity into account to avoidliteral (he kicked the old bucket) or coincidental occurrences (he kicked the ball and the bucket fell down). To this end, we considered two main approaches : The first one is based on a language independent measure of VMWE variability. The second one consists in modeling the problem as a classification task on the basis of features relevant to the VMWE morphosyntactic variability, which led to a system (VarIDE) that participated in the PARSEME shared task on automatic identification of VMWEs in 2018
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Vagne, Frédéric. "Varices oesophagiennes sans hypertension portale (downhill varices) au cours d'une polythrombose du systeme cave par dysfibrinogenemie : a propos d'une observation." Université Louis Pasteur (Strasbourg) (1971-2008), 1985. http://www.theses.fr/1985STR1M264.
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PECEGO, GEORGES. "Sygep, un systeme de generation d'enonces de problemes dans des domaines varies." Paris 6, 1998. http://www.theses.fr/1998PA066277.
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Le travail de recherche accompli dans le cadre de la these a pour but de decrire sygep, un systeme a base de connaissances, qui cree des enonces de problemes independamment du domaine d'application. Partant du constat que dans les environnements interactifs assistes par ordinateur (eiao), les problemes proposes aux apprenants proviennent la plupart du temps de bases d'exercices preenregistres, il semblait interessant de doter ces systemes d'un outil de creation automatique d'exercices adaptes au niveau de l'apprenant. Les principaux domaines d'application sont l'electricite, la mecanique, la thermodynamique, la chimie. L'hypothese cognitive, sur laquelle s'appuie sygep, consiste a batir un probleme a rebours : a partir d'une grandeur precise, le systeme choisit une regle (formule) de sa base de connaissance permettant de rendre calculable cette grandeur but a partir de nouvelles grandeurs donnees. Le processus peut ainsi reiterer sur les donnees introduites complexifiant a chaque fois le probleme resultant. Sygep est toujours capable de fournir la solution aux problemes qu'il pose. De plus, il est possible d'introduire des contraintes permettant de guider la creation des problemes. Sygep est egalement dote de la possibilite d'evaluer lui-meme les enonces qu'il cree a partir de criteres objectifs et generaux, dont il extrait une mesure de difficulte et d'interet. Nous avons ensuite aborde d'autres types de problemes. Ainsi nous avons exploite le fait que les apprenants tendent a croire que tout est lineaire. Sygep est capable de creer des exercices specifiques en donnant des contre-exemples de cette fausse idee. De meme, nous avons tenu compte de ce qui fait la difference entre le novice et l'expert : la confusion entre loi fondamentale et traits de surface. Sygep est donc dote de la possibilite de creer des problemes couples, dont la resolution doit permettre a l'apprenant de distinguer les aspects de fond et de forme que peut recouvrir un probleme.
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Cropp, Robert James. "Implementation of respiratory-correlated cone-beam CT on Varian linac systems." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/37220.
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Respiratory-correlated (4D) X-ray CT scans produce a set of images corresponding to different phases of a patient's breathing cycle. In external beam radiotherapy, information about a tumor's motion due to respiration can be used to optimize a treatment plan, provided the patient can be accurately aligned for treatment. Cone-beam CT (CBCT) systems are becoming widespread on treatment linac units and are used to aid in alignment.
This thesis describes the implementation of respiratory-correlated cone-beam CT scans on two types of Varian units: iX and TrueBeam. Procedures for 4D CBCT scans on each type have been developed and used to image a moving phantom. The respiratory phase of the motion is recorded with the Varian Real-time Position Management (RPM) system, which uses optical tracking. To improve image quality, the gantry rotation speed is reduced below the default value of 6°/s: this reduces streak artifacts. Each projection image from the scan is assigned to one of ten phase bins according to its respiratory phase value. A 3D image is reconstructed for each phase bin with software developed for this project, which uses conventional Feldkamp-Davis-Kress filtered backprojection. Four 4D scans of a periodically moving phantom have been taken, with different gantry speeds and mAs values. To evaluate the effect of these scan parameters on image quality, and demonstrate a potential application of 4D CBCT, a procedure for automated tumor trajectory measurement has been developed. The
measurement uses image registration between phase images, with either a rigid translation or a B-spline deformation algorithm. In the highest-quality images, the displacements of an insert in the phantom are measured within 1 mm of the correct values by both algorithms. In lower-quality images the translation algorithm is more robust. The two algorithms give similar results when applied to 4D CT images of actual lung cancer patients.
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Campanini, Alessandro. "Online Parameters Estimation in Battery Systems for EV and PHEV Applications." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
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The main target of this thesis is to assess whether two among of the most advanced algorithms are able to perform an online parameters estimation. Starting from a current profile generated by a real driving cycle and applied to an Electric Circuit Model (ECM) with known parameters, a voltage profile is generated. Then, Extended Kalman Filter (EKF) and Varied-Parameters Approach (VPA) will be employed both to the known system and to a real battery cell profile with unknown parameters. The research has led to the result that even if the two algorithms present opposite characteristics in terms of accuracy and computational effort, the are some common results. Convergence and accuracy are strictly dependent on the prior knowledge of the ECM parameter curves and on the hypothesis done to simplify the model, such as variables dependences, circuital complexity etc. Therefore, when applying the algorithms to a known system, perfect correspondence between estimated and real parameters is found, whereas when they are applied to an unknow system the converge in not reached. Therefore, for future researches might be recommend introducing Temperature, Current and Aging dependence in the system model, as well as generating voltage profiles from more complex ECMs and performing simulations with the same ECM used in this thesis.
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Orstavik, Odd-Halvdan Sakse. "Analysis of chaotic multi-variate time-series from spatio-temporal dynamical systems." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314071.
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Bajwa, Moazzum. "Dendritic Spine Density Varies Between Unisensory and Multisensory Cortical Regions." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/87.
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In the brain, the dendritic spine is a point of information exchange that extends the neuronal surface on which synapses occur, as well as facilitates and stabilizes those contacts. Furthermore, dendritic spines dynamically change in shape and number in response to a variety of factors. Dendritic spine numbers are reduced in mental retardation, enhanced during development, sensory enrichment or physical exercise, or fluctuate during the reproductive cycle. Thus, for a given neuron type, it might be expected that dendritic spine number might achieve a dynamic optimum. Indeed, many studies of spine density of pyramidal neurons in sensory cortex indicate that an average of ~1.4 spines/micron occurs is present (Briner et al., 2010). Most such studies examined dendritic spines from primary sensory areas which are dominated by inputs from a single sensory modality. However, there are a large number of neural regions that receive inputs from more than one sensory modality and it is hypothesized that spine density should increase to accommodate these additional inputs. To test this hypothesis, the present experiments used Golgi-Cox stained layer 2-3 pyramidal neurons from ferret primary somatosensory (S1) and auditory (A1) cortical regions, as well as from the higher-level rostral posterior parietal (PPr) and lateral rostral suprasylvian (LRSS) multisensory areas. Spine densities in S1 (avg 1.309 ± 0.247 spines/micron) and A1 (avg 1.343 ± 0.273 spines/micron) were measured to be significantly greater (p<0.05, t-test) than those observed in multisensory regions PPr (avg 1.242 ± 0.205 spines/micron) or LRSS (avg 1.099 ± 0.217 spines/micron). These results also indicate that spine densities are greater in primary (S1, A1) than in higher-level (PPr, LRSS) sensory areas. The functional consequences of such unexpected findings are discussed in light of potential biophysical differences between unisensory and multisensory neurons.
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Silva, Marcos Henrique Carvalho. "Modelagem de motores a combustão interna com tecnologia FLEX." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/3/3142/tde-17072018-084552/.
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A modelagem de motores a combustão interna deve grande parte de sua importância ao uso de unidades de controle eletrônicas que buscam gerenciar as funções do motor. De forma a fornecer melhor suporte para o projetista de controle, a modelagem oferece informações que servem de planta, sobre a qual estratégias de controle serão desenvolvidas. Nesta dissertação, procurou-se estudar e modelar cinco fenômenos: a admissão de ar e de combustível, a produção de energia efetiva através da combustão, a evolução térmica do motor e o comportamento dos gases no sistema de exaustão. Investigou-se também, em todos estes fenômenos, a influência do uso de composição variada gasolina/etanol. Na admissão de ar, buscou-se estudar como a abertura da válvula borboleta e a velocidade do motor influenciam no fluxo de ar admitido, ponderando esta grandeza através de um fator de correção denominado eficiência volumétrica. Na admissão de combustível, no caso modelada para motores com injeção indireta na porta, procurou-se explanar quantitativamente sobre os diversos aspectos que influenciam a evaporação do combustível. Na geração de energia útil, priorizou-se a análise de como as características do motor e da combustão afetam a produção de torque. Na evolução térmica do motor, examinaram-se os principais fluxos energéticos do motor e os aspectos que os influenciam. Ademais, foram executadas as validações dos modelos levantados para o motor EA 111 VHT 1.6l. Os resultados, com seus respectivos erros, podem ser encontrados neste trabalho.The internal combustion engine modeling owes big part of its importance to the use of electronic control units that aim to manage the engine functions. To provide better support to the control designer, the modeling offers information that can compose the plant, on which control strategies will be developed. In this master thesis, it was sought to study and to model five phenomena: the air intake and the fuel admission, the effective energy production from the combustion, the engine thermic evolution and the gas behavior in the exhaust system. It was also considered how the influence of the gasoline/ethanol varied composition affects all these phenomena. In the air intake, it was studied how the butterfly valve opening and the engine speed influence the intake air flow, pondering this variable through a correction factor named volumetric efficiency. In the fuel admission, in the case of this study modelled for port-fuel injection engines, it was attempted to explain quantitatively the many aspects that influence the fuel evaporation. In the mechanical energy generation, it was prioritized the analysis about how the engine and combustion characteristics affect the torque production. In the engine thermic evolution, it was examined the major energy flows and the aspects that influence them. Also, the validations of the models raised for the EA 111 VHT 1.6l engine were executed. The results, with its respective errors, can be found in this work.
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Carneiro, Fred Olavo Aragão Andrade. "Fatores preditivos ecoendoscópicos da recidiva de varizes esofágicas após erradicação com ligadura elástica em pacientes com doença hepática crônica avançada." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/5/5168/tde-10032017-102256/.
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INTRODUÇÃO: A recidiva de varizes é frequente após tratamento endoscópico com ligadura elástica para a profilaxia secundária de hemorragia por rotura de varizes esofágicas em pacientes com doença hepática crônica avançada. Alguns estudos relacionaram tanto recidiva quanto ressangramento de varizes com características ecoendoscópicas de vasos paraesofágicos. OBJETIVO: Relacionar avaliações ecoendoscópicas de varizes paraesofágicas, veia ázigos e ducto torácico com recidiva de varizes após erradicação com ligadura elástica em pacientes com doença hepática crônica avançada através de estudo prospectivo e observacional. MÉTODOS: A análise ecoendoscópica foi realizada antes da terapia com ligadura elástica e 1 mês após a erradicação endoscópica das varizes. Os diâmetros máximos das varizes paraesofágicas, da veia ázigos e do ducto torácico foram avaliados em localizações ecoendoscópicas prédeterminadas. Após a erradicação das varizes, os pacientes foram submetidos a endoscopias a cada 3 meses durante o período de 1 ano. Foi verificado se alguma das características ecoendoscópicas analisadas poderia predizer a recidiva das varizes. RESULTADOS: Um total de 30 pacientes completou o protocolo de seguimento por 1 ano. Dezessete (57%) pacientes apresentaram recidiva de varizes. Não houve relação entre os diâmetros máximos da veia ázigos e do ducto torácico com a recidiva de varizes. O diâmetro máximo de varizes paraesofágicas foi fator preditivo para recidiva de varizes em ambos os períodos avaliados. Os diâmetros das varizes paraesofágicas que melhor se relacionaram com recidiva de varizes foram 6,3 mm antes da ligadura elástica (sensibilidade de 52,9%, especificidade de 92,3% e área sob a curva ROC de 0,749) e 4 mm após a ligadura elástica (70,6% de sensibilidade, 84,6% de especificidade e área sob a curva ROC de 0,801). CONCLUSÃO: A medida ecoendoscópica do diâmetro das varizes paraesofágicas pode predizer a recidiva das varizes esofágicas no primeiro ano após a erradicação com ligadura elástica. O diâmetro de varizes paraesofágicas após a ligadura elástica é o melhor fator preditivo, pois apresenta menor valor de corte, maior sensibilidade e maior área sob a curva ROCINTRODUCTION: Variceal recurrence after endoscopic band ligation for secondary prophylaxis is a frequent event. Some studies have reported a correlation between variceal recurrence and variceal re-bleeding with the endoscopic ultrasound (EUS) features of para-esophageal vessels. OBJECTIVE: A prospective observational study was conducted to correlate EUS evaluation of para-esophageal varices, azygos vein and thoracic duct with variceal recurrence after endoscopic band ligation variceal eradication in patients with in advanced chronic hepatic disease. METHODS: EUS was performed before and 1 month after endoscopic band ligation variceal eradication. Para-esophageal varices, azygos vein and thoracic duct maximum diameters were evaluated in pre-determined anatomic stations. After endoscopic band ligation variceal eradication, patients were submitted to endoscopic examinations every 3 months for 1 year. We looked for EUS features that could predict variceal recurrence. RESULTS: A total of 30 patients completed 1-year endoscopic follow-up. Seventeen (57%) patients presented variceal recurrence. There was no correlation between azygos vein and thoracic duct diameters with variceal recurrence. The maximum diameter of para-esophageal varices predicted variceal recurrence in both evaluation periods. Para-esophageal varices diameters that best correlated with variceal recurrence were 6.3 mm before endoscopic band ligation (52.9% sensitivity, 92.3% specificity, and 0.749 area under ROC curve); and 4 mm after endoscopic band ligation (70.6% sensitivity, 84.6% specificity, and 0.801 area under ROC curve). CONCLUSION: We conclude that paraesophageal varices diameter measured by EUS predicts variceal recurrence within one year after endoscopic band ligation variceal eradication. Paraesophageal diameter after variceal eradication is a better recurrence predictor, because it has lower cut-off parameter, higher sensitivity and higher area under the ROC curve
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Wilhoite, David, Tyler D. O. Aasen, and Lawrence M. D. Schmidt. "Life threatening GI bleeding from stomal varices managed by TIPS and Amplatzer plug embolization." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/73.
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Stomal varices are a rare phenomenon that can infrequently develop in patients with enterostomies and portal hypertension. Acute gastrointestinal bleeding from stomal varices can be life threatening and is often a diagnostic challenge. We present a case of severe gastrointestinal hemorrhage from stomal varices requiring emergent intervention with transjugular intrahepatic portosystemic shunt (TIPS) and plug embolization.
A 61 year old male patient with a history of colorectal adenocarcinoma status post chemotherapy, radiation, along with low anterior colon resection with ostomy creation presented with a one day history of sudden onset of bright red blood from his colostomy site. He had a known history of decompensated cirrhosis related to hepatitis C and alcohol abuse. On arrival, the patient was tachycardic with borderline low blood pressure with evidence of bright red bleeding from his ostomy site. After initial resuscitation, a colonoscopy through the stoma revealed active bleeding from what appeared to be submucosal colonic varices. The patient continued to experience large volumes of blood loss and became more hemodynamically unstable. Cross sectional imaging showed colonic varices being fed by a branch of the inferior mesenteric vein. The patient underwent TIPS followed by Amplatzer plug embolization of the branch of the interior mesenteric vein that was feeding the colonic stomal varices. The patient’s bleeding was stopped by the combination of these therapeutic modalities and he recovered without complication.
The current standard of care for treatment of such varices is with either (1) local therapy with ligation or sclerotherapy, (2) surgical interventions such as stomal manipulation or vessel shunting, either transhepatic or portosystemic to reduce portal pressures, or (3) liver transplantation. Our patient required an unusual combination of TIPS and Amplatzer plug embolization to control his massive hemorrhage. This combination of therapies has been shown effective for the management of select cases of esophageal or gastric variceal bleeding; however, our case demonstrates that the application of the TIPS plus Amplatzer plug embolization can be applied more broadly to the rare scenario of colonic stomal varices.
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Alo, Micah. "Survivorship, growth and pigmentation responses of the marine ornamental invertebrate Tridacna maxima to varied irradiance levels in two different culture systems." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0012200.
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MENG, LI. "A BUILDING BLOCK APPROACH FOR DESIGNING SELF-SYNCHRONOUS CHAOTIC SYSTEMS FOR SECURE COMMUNICATION." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1057759148.
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Suciu, Oana Carina [Verfasser]. "Numerical methods based on direct discretizations for uni- and bi-variate population balance systems / Oana Carina Suciu." Berlin : Freie Universität Berlin, 2014. http://d-nb.info/1046563890/34.
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Hetel, Laurentiu. "Stabilité et commande robuste des systèmes à commutation." Phd thesis, Institut National Polytechnique de Lorraine - INPL, 2007. http://tel.archives-ouvertes.fr/tel-00202479.
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Les travaux de cette thèse portent sur l'analyse de stabilité et la synthèse de commandes robustes pour les systèmes linéaires à commutation en temps discret avec des incertitudes polytopiques et des incertitudes sur la loi de commutation. On considère des lois de commutations arbitraires et on montre que l'utilisation des fonctions de Lyapunov commutées dépendant de paramètres permet de déterminer des critères de stabilité et de stabilisation robuste moins conservatifs. Ensuite, des conditions de stabilité robuste pour les systèmes en temps discret avec une loi de commutation incertaine sont présentées en termes de temps minimum de séjour. Les résultats obtenus s'avèrent utiles dans le contexte de la commande numérique des systèmes continus en présence d'imprécisions sur les instants d'échantillonnage etl'application des commandes. Nous montrons comment une modélisation à base d'évènements permet de ramener le problème original à un problème spécifique aux systèmes à commutation avec des incertitudes polytopiques. Les résultats sont étendus au cas des systèmes à commutation continus commandés par des correcteurs numériques.
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Bulhões, Júnio Santos. "Metodologia de previsão utilizando identificação de sistemas aplicada a séries temporais." Universidade Federal de Goiás, 2018. http://repositorio.bc.ufg.br/tede/handle/tede/9078.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
This work proposes a methodology that uses spectral analysis and system identification in order to fill gaps in time series. The methodology proposes the implementation of predictions in time series of physical and chemical variables that are related with flood areas that are collected with no frequency. It is used predictive neural network with autoregressive model and classification neural network. Collected values are extracted from the original data set in order to later test and validate the proposed methodology. The results demonstrated the effectiveness of the methodology, which is able to predict the behavior of different variables using the previously recognized patterns in the time series.
Este trabalho propõe metodologia que utiliza análise espectral em conjunto com modelo de identificação de sistema para preenchimento de lacunas em séries temporais. A metodologia propõe realizar previsão em séries temporais de variáveis físicas e químicas relacionadas as inundações com frequência de coleta variável. Utiliza-se rede neural artificial de previsão com modelo autorregressivo e rede neural classificatória. Valores coletados são armazenados para posteriormente testar e validar a metodologia proposta. Os resultados alcançados demonstram a eficácia da metodologia, que é capaz de prever o comportamento de diferentes variáveis utilizando os padrões reconhecidos previamente nas séries temporais.
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Kawamura, Koei. "Infinite-variate extensions of Krawtchouk polynomials and zonal spherical functions over a local field." Kyoto University, 2018. http://hdl.handle.net/2433/232216.
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Liedberg, Cajsa, and Britta Lago. "Varied amount of information for two different user profiles : Establishing the relationship between novice and expert users’ knowledge level and their preferred amount of information displayed." Thesis, Jönköping University, JTH, Avdelningen för datateknik och informatik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-53201.
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Palla, Srikanth. "A Multi-Variate Analysis of SMTP Paths and Relays to Restrict Spam and Phishing Attacks in Emails." Thesis, University of North Texas, 2006. https://digital.library.unt.edu/ark:/67531/metadc5402/.
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The classifier discussed in this thesis considers the path traversed by an email (instead of its content) and reputation of the relays, features inaccessible to spammers. Groups of spammers and individual behaviors of a spammer in a given domain were analyzed to yield association patterns, which were then used to identify similar spammers. Unsolicited and phishing emails were successfully isolated from legitimate emails, using analysis results. Spammers and phishers are also categorized into serial spammers/phishers, recent spammers/phishers, prospective spammers/phishers, and suspects. Legitimate emails and trusted domains are classified into socially close (family members, friends), socially distinct (strangers etc), and opt-outs (resolved false positives and false negatives). Overall this classifier resulted in far less false positives when compared to current filters like SpamAssassin, achieving a 98.65% precision, which is well comparable to the precisions achieved by SPF, DNSRBL blacklists.
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Laharotte, Pierre-Antoine. "Contributions à la prévision court-terme, multi-échelle et multi-variée, par apprentissage statistique du trafic routier." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSET013/document.
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La maturité de la télématique et des technologies de l’information et la communication (TIC), ainsi que l’avènement du big data dans le transport ont conduit à des développements foisonnants dans le domaine des systèmes de transports intelligents (ITS), aussi bien sur le plan des technologies de recueil que du traitement innovant de l’information. Il est désormais possible de connaître les conditions de circulation et les états de trafic sur la plupart des sections d’un réseau routier sans avoir recours à des infrastructures intrusives de collecte de données, de transmettre l’information résultante via des réseaux sans fil et de traiter rapidement toutes ces données multi-sources disponibles. La constitution de grandes bases de données a naturellement fait évoluer la pratique de gestion du trafic et plus particulièrement les méthodes de prévision. Ces méthodes ont connu un renouveau en s’inspirant des travaux produits en apprentissage statistique. Néanmoins, la façon d’appréhender le problème de la prévision est restée à une échelle locale. Pour chaque section de route, un modèle de prévision est adapté et optimisé. Notre travail de thèse présente un cadre de prévision du trafic routier qui aborde la question à l’échelle du réseau. L’étude menée au sein de ces travaux de thèse vise à exposer et évaluer cette nouvelle approche, dite globale, au regard d’approches usuelles, puis à analyser sa sensibilité vis-à-vis de divers facteurs. Après un positionnement par rapport à l’état de l’art en théorie du trafic, le cadre prédictif fondé sur des méthodes de prévision multi-variées par apprentissage est détaillé. Une version multidimensionnelle des k plus proches voisins, modèle parcimonieux et simple, est évaluée sur divers cas d’études. L’originalité réside dans l’exploitation de données issues de méthodes innovantes de collecte (e.g. Bluetooth, véhicules traceurs, véhicules connectés). Par la suite, les performances de l’approche initiale sont comparées à d’autres méthodes d’apprentissage. Un effort particulier est porté sur l’adaptation de méthodes à noyaux au cadre prédictif global. Les performances obtenues laissent entrevoir une typologie des méthodes en fonction des caractéristiques spatiotemporelles du réseau. Afin d’améliorer les performances en prévision et de réduire les temps de calcul, une méthode d’identification et de sélection des sections critiques du réseau est proposée. Les résultats prouvent qu’un sous-ensemble restreint de sections est en effet suffisant pour garantir des performances satisfaisantes en généralisation. Enfin, la résilience du cadre prédictif est évaluée au regard des événements non récurrents affectant le fonctionnement nominal du réseau, comme des incidents ou des conditions météorologiques dégradées. Les résultats soulignent l’impact de ces conditions non récurrentes sur la prévision temps-réel de la dynamique court-terme d’un réseau et permettent de dresser une feuille de route pour l’élaboration d’un cadre prédictif résilient et opérationnel. Cette nouvelle vision de la prévision s’inscrit dans les perspectives actuelles en termes d’applications sur les modules embarqués et les objectifs des gestionnaires d’infrastructuresThe maturity of information and communication technologies and the advent of Big Data have led to substantial developments in intelligent transportation systems (ITS) : from data collection to innovative processing solutions. Knowledge of current traffic states is available over most of the network range without the use of intrusive infrastructure-side collection devices, instead relying on wireless transmission of multi-source data. The increasing use of huge databases had a strong influence on traffic management, including forecasting methods. These approaches followed the recent trend towards innovative works on statistical learning. However, the prediction problem remains mainly focused on the local scale. The prediction for each road link relies on a dedicated, optimized and adapted prediction model. Our work introduces a traffic-forecasting framework able to tackle network scale problems. The study conducted in this thesis aims to present and evaluate this new “global” approach, in comparison to most-used existing works, and then to analyze its sensitivity to several factors. The traffic-forecasting framework, based on multi-variate learning methods, is detailed after a review of the literature on traffic flow theory. A multi-dimensional version of the k nearest-neighbors, a simple and sparse model, is evaluated through several use cases. The originality of the work stands on the processing approach, applied to data collected through new measurement process (e.g. Bluetooth, floating car data, connected vehicles). Then, the performance of our primary approach is compared to other learning-based methods. We propose an adaptation of kernel-based methods for the global prediction framework. The obtained results show that global approaches perform as well as usual approaches. The spatial and temporal specificities of the methods are highlighted according to the prediction accuracy. To improve the forecasting accuracy and reduce the computation time, we propose an identification and selection method targeting critical links. The results demonstrate that the use of a restricted subset of links is sufficient to ensure acceptable performances during validation tests. Finally, the prediction framework resilience is evaluated with respect to non-recurrent events as incidents or adverse weather conditions affecting the nominal network operations. The results highlight the impact of these non-recurrent conditions on real-time forecasting of short-term network dynamics. This enables the design of a further operational and resilient prediction framework. This perspective of forecasting matches the current applications relying on embedded systems and addressing the traffic network supervisor’s expectations
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Bouvier-Joly, Catherine. "Une approche des diviseurs essentiels des singularités algébriques." Grenoble 1, 1993. http://www.theses.fr/1993GRE10027.
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Pour une variete algebrique v, on cherche ici a caracteriser ceux parmi les diviseurs exceptionnels d'une desingularisation de v qui apparaissent aussi sur toutes les autres. Ils sont dits essentiels relativement a v. On se pose egalement le probleme de l'existence d'une desingularisation essentielle de v, dont les diviseurs exceptionnels sont les diviseurs exceptionnels sont tous essentiels. Une variete v torique et affine est associee a un semi-groupe dans un reseau; on en etudie le systeme generateur minimal g. On montre que les diviseurs essentiels pour les desingularisations equivariantes de v sont les orbites de codimension 1 du tore determinees par les elements de g. Si v est de dimension 3, on construit une desingularisation essentielle equivariante, ou g desingularisation, a partir d'un modele terminal minimal quelconque de v. En fait, une g-desingularisation se factorise toujours par un modele terminal minimal et elle est unique lorsque v est elle-meme terminale et q-factorielle. Les demonstrations portent sur la combinatoire des eventails. Dans le cas ou le corps de base est c, on utilise des resultats dus a mori pour etablir que les diviseurs essentiels equivariants restent essentiels pour les desingularisations non equivariantes. On donne aussi les exemples d'une variete torique de dimension 4, puis d'une variete de dimension 3 terminale d'indice 1, qui ne possedent pas de desingularisation essentielle
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Cá, Lamo-Guzmá N. Bernardo, Vinatea-Serrano Luis De, Alejandro Piscoya, and Eddy R. Segura. "Performance of the FIB-4 index in esophageal varices screening in patients with the diagnosis of liver cirrhosis." Sociedad de Gastroenterología del Perú, 2020. http://hdl.handle.net/10757/655701.
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INTRODUCTION: The diagnosis of esophageal varices in cirrhotic patients is made by the upper gastrointestinal endoscopy. Multiple non-invasive predictors have been studied for the diag-nosis of esophageal varices. The objective of this study is to testthe FIB4 index as screening of esophageal varices in patients with liver cirrhosis. MATERIALS AND METHODS: A cross-sectional analytic study was developed in four national hospital using hepatic cirrhosis patient's medi-cal files. We assessed the information using univariate and bivariate analysis, sensitivity, speci-ficity, predictive positive and negative value, the positive and negative likelihood ratio calcu-lation of the esophageal varices screening and its size. We built ROC curve for every analysis group. RESULTS: The study included 289 liver cirrhosis patients. Most of the patients were male (54.33%). 77.85% patients had esophageal varices. The distribution of varices was 19.03%, 35.99% and 22.84% for large, medium and small varices, respectively. In the FIB-4 index analysis for the presence of varices, it was found a sensitivity of 81.3%, specificity of 37.5% (AUC: 0.57). The calculation for variceal size showed a sensitivity of 81.8%, specificity of 23.9% (AUC: 0.50). In the analysis of FIB-4 index for prophylaxis groups was found a sensitivity of 81.8% and a specificity of 28.5% (AUC: 0.54). CONCLUSIONS: The FIB-4 index has no good performance in the screening for the presence of esophageal varices and its size in liver cirrhosis patients.Revisión por pares
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Pereyra, Angel. "Variétés toriques et points infiniment voisins." Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10096.
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Dans ce travail, nous nous interessons a la geometrie des constellations ; c'est-a-dire aux suites des eclatements des points se projetant sur un point fixe - l'origine - d'une variete algebrique lisse. Si la variete de depart est une variete torique, et que les points eclates sont des points fixes pour l'action du tore, on dit que la constellation est torique. Nous donnons une caracterisation des diagrammes d'enriques qui sont associes a des constellations toriques par rapport a la relation de proximite entre les points eclates de la constellation. De plus, nous construisons une constellation torique de dimension minimale qu'induit un tel diagramme d'enriques. Les ideaux complets dans l'anneau local a l'origine a support dans une constellation c sont un semigroupe de rang fini, qu'on appelle le semigroupe associe a c. Nous associons a chaque constellation torique un objet combinatoire, le pl-diagramme d'enriques, qui permet de retrouver la relation de proximite lineaire - relation plus fine que celle de proximite -, avec laquelle on obtient le semigroupe associe. De plus, si deux constellations toriques ont le meme pl-diagramme d'enriques, alors les semigroupes associes sont isomorphes. D'autre part, etant donne un pl-diagramme d'enriques, nous construisons une constellation torique de dimension minimale telle que son pl-diagramme d'enriques soit celui du depart. Comme application, nous montrons que si le semigroupe associe a une constellation torique est libre, alors il existe une constellation de dimension deux avec le meme semigroupe associe, prouvant ainsi une reciproque au theoreme de zariski sur la factorisation des ideaux complets des anneaux locaux reguliers de dimension deux.
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Stolovitch, Laurent. "Classification analytique de champs de vecteurs." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10243.
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Cette these a pour objet l'etude des champs de vecteurs analytiques au voisinage d'un point singulier en dimension quelconque. Elle est composee de deux articles. Le premier montre l'existence de varietes analytiques invariantes d'un champ de vecteurs sous des hypotheses de petits diviseurs diophantiens et de resonnances positives. Dans le cas de la dimension 2, nous retrouvons les resultats de dulac. Le deuxieme etudie les champs de vecteurs 1-resonnant. Nous y etudions la linearisation de systemes non-lineaires a singularite irreguliere. Nous montrons l'existence de transformations analytiques dans des domaines sectoriels conjuguant un champ de vecteurs 1-resonnant a sa forme normale, sous certaines hypotheses ; puis, nous donnons une classification analytique des champs ayant une meme forme normale. Nous retrouvons, en dimension 2, celles faites par martinet-ramis sans distinguer les cas du col et du nud-col
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Lacroix, Benoit. "Normer pour mieux varier ? La différenciation comportementale par les normes, et son application au trafic dans les simulateurs de conduite." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2009. http://tel.archives-ouvertes.fr/tel-00527846.
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Dans les simulations centrées individu, la variété et la cohérence du comportement des agents sont des critères importants pour le réalisme et la validité de la simulation. Dans ce travail, nous nous sommes intéressés à la prise en compte simultanée de ces deux éléments. Nous proposons un modèle de différenciation comportementale, qui se décline en un outil dont les principaux apports sont d'être générique, non-intrusif, et de permettre une conception en dehors de l'agent. Le modèle s'articule selon trois axes. Tout d'abord, il décrit les comportements des agents par des normes. Celles-ci fournissent un profil comportemental à la conception, et un contrôle de la conformité à l'exécution. Ensuite, le processus de génération des comportements permet d'autoriser la création d'agents déviants ou en violation. Il inlfue pour cela sur le déterminisme du mécanisme. Enfin, les normes peuvent être inférées à partir de simulations enregistrées ou de situations réelles, afin d'analyser les résultats des expérimentations et d'automatiser la configuration du modèle. Nous avons appliqué cet outil à la simulation de trafic dans SCANeR, l'application développée et utilisée par Renault pour ses simulateurs de conduite. Les développements réalisés au cours de la thèse introduisent dans le trafic des styles de conduite spécifiés sous forme de normes, par exemple des conducteurs prudents ou agressifs. Ils permettent ensuite de peupler l'environnement de manière automatisée. Au delà de l'amélioration subjective du réalisme, les expérimentations réalisées démontrent les apports de l'outil sur la variété et la représentativité des comportements obtenus.
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Lacroix, Benoît. "Normer pour mieux varier ? : la différenciation comportementale par les normes, et son application au trafic dans les simulateurs de conduite." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2009. http://tel.archives-ouvertes.fr/tel-00835831.
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Les simulateurs de conduite sont utilisées par l'industrie automobile pour le développement de systèmes d'aide à la conduite, des études d'ergonomie, de design, ou encore du comportement des conducteurs. L'objectif est d'améliorer la sécurité des véhicules, et de réduire coûts et délais des projets. Dans les simulateurs, le conducteur évolue dans un trafic simulé dont le réalisme est crucial pour la validité des résultats : les réactions d'un conducteur sont d'autant plus correctes qu'il perçoit l'environnement comme réel. Dans les approches centrées individu, comme ici le trafic, un des critères important pour le réalisme est la variété comportementale des agents. De plus, les comportements doivent également être cohérents : l'apparition de situations aberrantes est très pénalisante pour l'immersion. Cependant, ces deux aspects ne sont généralement pas pris en compte simultanément. Dans ce travail, nous nous sommes donc intéressés à la question suivante : dans les approches centrées individus, augmenter la variété des comportements des agents tout en préservant leur cohérence améliore-t-il le réalisme ? Par ailleurs, le contexte industriel des travaux, effectués en convention Cifre chez Renault, impliquait des besoins spécifiques : il fallait concevoir un outil qui permette à la fois aux experts de spécifier des comportements variés et cohérents, et aux utilisateurs finaux de les exploiter facilement. Nous proposons dans ce travail un modèle de différenciation comportementale, qui se décline en un outil dont les principaux apports sont d'être générique, non-intrusif, et de permettre une conception en dehors de l'agent. Le modèle s'articule selon trois axes. Tout d'abord, il décrit les comportements des agents par des normes. Celles-ci fournissent un profil comportemental à la conception, et un contrôle de la conformitéà l'exécution. Ensuite, le processus de génération des comportements permet d'autoriser la création d'agents déviants ou en violation. Il influe pour cela sur le déterminisme du mécanisme. Enfin, les normes peuvent être inférées à partir de simulations enregistrées ou de situations réelles, afin d'analyser les résultats des expérimentations et d'automatiser la configuration du modèle. Nous avons appliqué cet outil à la simulation de trafic dans scaner, l'application développée et utilisée par le Centre Technique de Simulation de Renault pour ses simulateurs de conduite. Les modules logiciels développés au cours de la thèse introduisent dans le trafic des styles de conduite spécifiés sous forme de normes, par exemple des conducteurs prudents ou agressifs. Ils permettent ensuite de peupler l'environnement de manière automatisée, et de faire évoluer facilement les scénarios existants. Ces développements sont d'ores et déjà intégrés dans la version commerciale de l'application. Au delà de l'amélioration subjective du réalisme, les expérimentations réalisées démontrent les apports de l'outil sur la variété et la représentativité des comportements obtenus.
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Alshamrany, Abdullah. "Determination Of Dose Effects When Including Attenuation Of The Treatment Table Into Treatment Planning Computer Modeling." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1520859358953399.
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Wan, Jui. "Exploring RayStation Treatment Planning System: Commissioning Varian TrueBeam Photon and Electron Energies, and Feasibility of Using FFF Photon Beam to Deliver Conventional Flat Beam." University of Toledo Health Science Campus / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=mco1501843246429305.
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Veltz, Romain. "Nonlinear analysis methods in neural field models." Thesis, Paris Est, 2011. http://www.theses.fr/2011PEST1056/document.
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Cette thèse traite de modèles mésoscopiques de cortex appelés champs neuronaux. Les équations des champs neuronaux décrivent l'activité corticale de populations de neurones, ayant des propriétés anatomiques/fonctionnelles communes. Elles ont été introduites dans les années 1950 et portent le nom d'équations de Wilson et Cowan. Mathématiquement, elles consistent en des équations intégro-différentielles avec retards, les retards modélisant les délais de propagation des signaux ainsi que le passage des signaux à travers les synapses et l'arbre dendritique. Dans la première partie, nous rappelons la biologie nécessaire à la compréhension de cette thèse et dérivons les équations principales. Puis, nous étudions ces équations du point de vue des systèmes dynamiques en caractérisant leurs points d'équilibres et la dynamique dans la seconde partie. Dans la troisième partie, nous étudions de façon générale ces équations à retards en donnant des formules pour les diagrammes de bifurcation, en prouvant un théorème de la variété centrale et en calculant les principales formes normales. Nous appliquons tout d'abord ces résultats à des champs neuronaux simples mono-dimensionnels qui permettent une étude détaillée de la dynamique. Enfin, dans la dernière partie, nous appliquons ces différents résultats à trois modèles de cortex visuel. Les deux premiers modèles sont issus de la littérature et décrivent respectivement une hypercolonne, /i.e./ l'élément de base de la première aire visuelle (V1) et un réseau de telles hypercolonnes. Le dernier modèle est un nouveau modèle de V1 qui généralise les deux modèles précédents tout en permettant une étude poussée des effets spécifiques des retardsThis thesis deals with mesoscopic models of cortex called neural fields. The neural field equations describe the activity of neuronal populations, with common anatomical / functional properties. They were introduced in the 1950s and are called the equations of Wilson and Cowan. Mathematically, they consist of integro-differential equations with delays, the delays modeling the signal propagation and the passage of signals across synapses and the dendritic tree. In the first part, we recall the biology necessary to understand this thesis and derive the main equations. Then, we study these equations with the theory of dynamical systems by characterizing their equilibrium points and dynamics in the second part. In the third part, we study these delayed equations in general by giving formulas for the bifurcation diagrams, by proving a center manifold theorem, and by calculating the principal normal forms. We apply these results to one-dimensional neural fields which allows a detailed study of the dynamics. Finally, in the last part, we study three models of visual cortex. The first two models are from the literature and describe respectively a hypercolumn, i.e. the basic element of the first visual area (V1) and a network of such hypercolumns. The latest model is a new model of V1 which generalizes the two previous models while allowing a detailed study of specific effects of delays
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Pinto, Felipe Alves Pereira. "An automated approach for performance deviation analysis of evolving software systems." Universidade Federal do Rio Grande do Norte, 2015. http://repositorio.ufrn.br/handle/123456789/21132.
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The maintenance and evolution of software systems have become a critical task over the last years due to the diversity and high demand of features, devices and users. The ability to understand and analyze how newly introduced changes impact the quality attributes of the architecture of those software systems is an essential prerequisite for avoiding the deterioration of the engineering quality of them during their evolution. This thesis proposes an automated approach for the deviation analysis of the quality attribute of performance in terms of execution time (response time). It is implemented by a framework that adopts dynamic analysis and mining software repository techniques to provide an automated way to revel potential sources - commits and issues - of performance deviation in scenarios of an evolving software system. The approach defines four phases: (i) preparation - choosing the scenarios and preparing the target releases; (ii) dynamic analysis - determining the performance of scenarios and methods by calculating their execution time; (iii) deviation analysis - processing and comparing the results of the dynamic analysis for different releases; and (iv) repository mining - identifying development issues and commits associated with performance deviation. Several empirical studies have been developed to assess the approach from different perspectives. An initial study shows the feasibility of the approach to support traceability of quality attributes with static analysis. An exploratory study analyzed the usefulness and domain independence of the proposal in automatically identifying source code assets with performance deviation and the changes that have affected them during an evolution. This study was performed using three systems: (i) SIGAA - a web academic management system; (ii) ArgoUML - an UML modeling tool; and (iii) Netty - a network application framework. A third study has performed an evolutionary analysis of applying the approach to multiple releases of Netty, and the web frameworks Wicket and Jetty. It has analyzed twenty-one releases (seven releases of each system) and addressed a total of 57 scenarios. Overall, we have found 14 scenarios with significant performance deviation for Netty, 13 for Wicket, and 9 for Jetty. In addition, the feedback obtained from an online survey with eight developers of Netty, Wicket and Jetty is also discussed. Finally, in our last study, we built a performance regression model in order to indicate the properties of code changes that are more likely to cause performance degradation. We mined a total of 997 commits, of which 103 were retrieved from degraded code assets, 19 from optimized, while 875 had no impact on execution time. Number of days before release and day of week were the most relevant variables of commits that cause performance degradation in our model. The receiver operating characteristic (ROC) area of our regression model is 60%, which means that deciding if a commit will cause performance degradation or not by using the model is 10% better than a random guess.
A manuten??o e evolu??o de sistemas de software tornou-se uma tarefa bastante cr?tica ao longo dos ?ltimos anos devido ? diversidade e alta demanda de funcionalidades, dispositivos e usu?rios. Entender e analisar como novas mudan?as impactam os atributos de qualidade da arquitetura de tais sistemas ? um pr?-requisito essencial para evitar a deteriora??o de sua qualidade durante sua evolu??o. Esta tese prop?e uma abordagem automatizada para a an?lise de varia??o do atributo de qualidade de desempenho em termos de tempo de execu??o (tempo de resposta). Ela ? implementada por um framework que adota t?cnicas de an?lise din?mica e minera??o de reposit?rio de software para fornecer uma forma automatizada de revelar fontes potenciais ? commits e issues ? de varia??o de desempenho em cen?rios durante a evolu??o de sistemas de software. A abordagem define quatro fases: (i) prepara??o ? escolher os cen?rios e preparar os releases alvos? (ii) an?lise din?mica ? determinar o desempenho de cen?rios e m?todos calculando seus tempos de execu??o? (iii) an?lise de varia??o ? processar e comparar os resultados da an?lise din?mica para releases diferentes? e (iv) minera??o de reposit?rio ? identificar issues e commits associados com a varia??o de desempenho detectada. Estudos emp?ricos foram realizados para avaliar a abordagem de diferentes perspectivas. Um estudo explorat?rio analisou a viabilidade de se aplicar a abordagem em sistemas de diferentes dom?nios para identificar automaticamente elementos de c?digo fonte com varia??o de desempenho e as mudan?as que afetaram tais elementos durante uma evolu??o. Esse estudo analisou tr?s sistemas: (i) SIGAA ? um sistema web para ger?ncia acad?mica? (ii) ArgoUML ? uma ferramenta de modelagem UML? e (iii) Netty ? um framework para aplica??es de rede. Outro estudo realizou uma an?lise evolucion?ria ao aplicar a abordagem em m?ltiplos releases do Netty, e dos frameworks web Wicket e Jetty. Nesse estudo foram analisados 21 releases (sete de cada sistema), totalizando 57 cen?rios. Em resumo, foram encontrados 14 cen?rios com varia??o significante de desempenho para Netty, 13 para Wicket e 9 para Jetty. Adicionalmente, foi obtido feedback de oito desenvolvedores desses sistemas atrav?s de um formul?rio online. Finalmente, no ?ltimo estudo, um modelo de regress?o para desempenho foi desenvolvido visando indicar propriedades de commits que s?o mais prov?veis a causar degrada??o de desempenho. No geral, 997 commits foram minerados, sendo 103 recuperados de elementos de c?digo fonte degradados e 19 de otimizados, enquanto 875 n?o tiveram impacto no tempo de execu??o. O n?mero de dias antes de disponibilizar o release e o dia da semana se mostraram como as vari?veis mais relevantes dos commits que degradam desempenho no nosso modelo. A ?rea de caracter?stica de opera??o do receptor (ROC ? Receiver Operating Characteristic) do modelo de regress?o ? 60%, o que significa que usar o modelo para decidir se um commit causar? degrada??o ou n?o ? 10% melhor do que uma decis?o aleat?ria.
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Pontier, Monique. "Filtrage et controle de processus stochastiques soumis a des contraintes." Orléans, 1987. http://www.theses.fr/1987ORLE2016.
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Del, Real Tamariz Annabell. "Modelagem computacional de dados e controle inteligente no espaço de estado." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260207.
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Orientador: Celso Pascoli BotturaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: Este estudo apresenta contribuições para modelagem computacional de dados multivariáveis no espaço de estado, tanto com sistemas lineares invariantes como com variantes no tempo. Propomos para modelagem determinística-estocástica de dados ruidosos, o Algoritmo MOESP_AOKI. Propomos, utilizando Redes Neurais Recorrentes multicamadas, algoritmos para resolver a Equação Algébrica de Riccati Discreta bem como a Inequação Algébrica de Riccati Discreta, via Desigualdades Matriciais Lineares. Propomos um esquema de controle adaptativo com Escalonamento de Ganhos, baseado em Redes Neurais, para sistemas multivariáveis discretos variantes no tempo, identificados pelo algoritmo MOESP_VAR, também proposto nesta tese. Em síntese, uma estrutura de controle inteligente para sistemas discretos multivariáveis variantes no tempo, através de uma abordagem que pode ser chamada ILPV (Intelligent Linear Parameter Varying), é proposta e implementada. Um controlador LPV Inteligente, para dados computacionalmente modelados pelo algoritmo MOESP_VAR, é concretizado, implementado e testado com bons resultados
Abstract: This study presents contributions for state space multivariable computational data modelling with discrete time invariant as well as with time varying linear systems. A proposal for Deterministic-Estocastica Modelling of noisy data, MOESP_AOKI Algorithm, is made. We present proposals forsolving the Discrete-Time Algebraic Riccati Equation as well as the associate Linear Matrix Inequalityusing a multilayer Recurrent Neural Network approaches. An Intelligent Linear Parameter Varying(ILPV) control approach for multivariable discrete Linear Time Varying (LTV) systems identified bythe MOESP_VAR algorithm, are both proposed. A gain scheduling adaptive control scheme based on neural networks is designed to tune on-line the optimal controllers. In synthesis, an Intelligent Linear Parameter Varying (ILPV) Control approach for multivariable discrete Linear Time Varying Systems (LTV), identified by the algorithm MOESP_VAR, is proposed. This way an Intelligent LPV Control for multivariable data computationally modeled via the MOESP_VAR algorithm is structured, implemented and tested with good results
Doutorado
Automação
Doutor em Engenharia Elétrica
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Erkki, Robert, and Philip Johnsson. "Quality Data Management in the Next Industrial Revolution : A Study of Prerequisites for Industry 4.0 at GKN Aerospace Sweden." Thesis, Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-69341.
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The so-called Industry 4.0 is by its agitators commonly denoted as the fourth industrial revolution and promises to turn the manufacturing sector on its head. However, everything that glimmers is not gold and in the backwash of hefty consultant fees questions arises: What are the drivers behind Industry 4.0? Which barriers exists? How does one prepare its manufacturing procedures in anticipation of the (if ever) coming era? What is the internet of things and what file sizes’ is characterised as big data? To answer these questions, this thesis aims to resolve the ambiguity surrounding the definitions of Industry 4.0, as well as clarify the fuzziness of a data-driven manufacturing approach. Ergo, the comprehensive usage of data, including collection and storage, quality control, and analysis. In order to do so, this thesis was carried out as a case study at GKN Aerospace Sweden (GAS). Through interviews and observations, as well as a literature review of the subject, the thesis examined different process’ data-driven needs from a quality management perspective. The findings of this thesis show that the collection of quality data at GAS is mainly concerned with explicitly stated customer requirements. As such, the data available for the examined processes is proven inadequate for multivariate analytics. The transition towards a data-driven state of manufacturing involves a five-stage process wherein data collection through sensors is seen as a key enabler for multivariate analytics and a deepened process knowledge. Together, these efforts form the prerequisites for Industry 4.0. In order to effectively start transition towards Industry 4.0, near-time recommendations for GAS includes: capture all data, with emphasize on process data; improve the accessibility of data; and ultimately taking advantage of advanced analytics. Collectively, these undertakings pave the way for the actual improvements of Industry 4.0, such as digital twins, machine cognition, and process self-optimization. Finally, due to the delimitations of the case study, the findings are but generalized for companies with similar characteristics, i.e. complex processes with low volumes.
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Chen, Wei, and 陳瑋. "Applying Fully Sequential Procedures for Comparing Constrained Systems with Control Variate." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/94acmh.
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碩士國立中央大學
工業管理研究所
106
Ranking and Selection (R&S) is a kind of stochastic simulation for finding the system with best or near-best performance from among a finite number of alternatives. It also allows the experimenters to obtain results with a certain level of confidence. However, because of managerial or physical limits, sometimes we will face constraints on other performances. Therefore, Andradottir and Kim (2010) developed a Feasibility checking procedure (FCP) to find feasible or near-feasible systems which satisfied the stochastic constraints based on statistical theory. Nevertheless, the procedure can be inefficient when the number of candidate systems or the variances of sampling performances outputs are large. In this paper, we propose a new R&S procedure, combine the variance reduction techniques of Control variates (CV) with the FDP procedure. We provide a queuing example to compare our procedure with previous ones. In our procedure, we use a set of random variables that are correlated with the outputs of interest, whose means are known to the user, to replace the origin output. Since it can reduce the variance of the estimator for original, the new procedure is expected to be more efficient than other competitors in the sense that fewer observations and less computer time are needed to find the best system which under the constraints.
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McDougall, Simon. "Le mode de scrutin a-t-il un impact sur le processus de décision électorale et cet impact varie-t-il en fonction de la sophistication politique ?" Thèse, 2004. http://hdl.handle.net/1866/17432.
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Ben, Rached Nadhir. "Rare Events Simulations with Applications to the Performance Evaluation of Wireless Communication Systems." Diss., 2018. http://hdl.handle.net/10754/629483.
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The probability that a sum of random variables (RVs) exceeds (respectively falls below) a given threshold, is often encountered in the performance analysis of wireless communication systems. Generally, a closed-form expression of the sum distribution does not exist and a naive Monte Carlo (MC) simulation is computationally expensive when dealing with rare events. An alternative approach is represented by the use of variance reduction techniques, known for their efficiency in requiring less computations for achieving the same accuracy requirement.
For the right-tail region, we develop a unified hazard rate twisting importance sampling (IS) technique that presents the advantage of being logarithmic efficient for arbitrary distributions under the independence assumption. A further improvement of this technique is then developed wherein the twisting is applied only to the components having more impacts on the probability of interest than others. Another challenging problem is when the components are correlated and distributed according to the Log-normal distribution. In this setting, we develop a generalized hybrid IS scheme based on a mean shifting and covariance matrix scaling techniques and we prove that the logarithmic efficiency holds again for two particular instances.
We also propose two unified IS approaches to estimate the left-tail of sums of independent positive RVs. The first applies to arbitrary distributions and enjoys the logarithmic efficiency criterion, whereas the second satisfies the bounded relative error criterion under a mild assumption but is only applicable to the case of independent and identically distributed RVs. The left-tail of correlated Log-normal variates is also considered. In fact, we construct an estimator combining an existing mean shifting IS approach with a control variate technique and prove that it possess the asymptotically vanishing relative error property. A further interesting problem is the left-tail estimation of sums of ordered RVs. Two estimators are presented. The first is based on IS and achieves the bounded relative error under a mild assumption. The second is based on conditional MC approach and achieves the bounded relative error property for the Generalized Gamma case and the logarithmic efficiency for the Log-normal case.
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Kadlecová, Hana. "Angličtina jako lingua franca v kontextu českého vzdělávacího systému." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-321478.
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Despite the predominance of English used by non-native speakers in international communication, the approach to teaching this language is still centred on the notion of acquiring English for the purpose of communication with native speakers. This thesis argues for acknowledgement of English as a lingua franca in the approach to teaching English. It also stresses the necessity of further investigations into the global use of English to better understand this phenomenon. A questionnaire was conducted with ten English teachers to see their opinions about some of the key issues of English as a lingua franca (for instance the concept of nativeness, the role of a teacher and the understanding of an error). As a result, it was found that despite some slow changes in individual opinions, the traditional view on teaching English is still prevalent. Both the theoretical research and the analysis of the questionnaire stress the need of implementing the concept of English as a lingua franca into teaching English as it is necessary to prepare students for the reality of global use of this language. Key words: English as a lingua franca, second language acquisition, nativeness, error, variation
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Tsai, Ming-Chou, and 蔡明洲. "Synthesis of nano-scale acrylic type of core-shell rubber tougheners with varied particle size and shell chemical composition and their phase characteristics in styrene/unsaturated polyester/additive ternary systems." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/q343pk.
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碩士國立臺灣科技大學
化學工程系
94
Nano-scale acrylic type of core-shell rubbers (CSR), with varied particle size and shell chemical composition, as tougheners for unsaturated polyester resins (UP) have been synthesized by emulsion polymerizations, and styrene (ST)/UP/CSR ternary systems with different miscibility have been designed. By using Debye’s equation and the group contribution method, the dipole moments of UP and the shell component of the CSR can be calculated, which can then explain the phase characteristics of the ST/UP/CSR ternary system prior to the reaction at 25℃ and 110℃. Also, the compatibility of the ST/UP/CSR ternary system during the cure at 110℃ has been investigated by the cured sample morphology as observed by scanning electron microscopy (SEM).
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Malladi, Raghuram. "Automatic signature verification system." 2013. http://hdl.handle.net/11394/3617.
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Philosophiae Doctor - PhDIn this thesis, we explore dynamic signature verification systems. Unlike other signature models, we use genuine signatures in this project as they are more appropriate in real world applications. Signature verification systems are typical examples of biometric devices that use physical and behavioral characteristics to verify that a person really is who he or she claims to be. Other popular biometric examples include fingerprint scanners and hand geometry devices. Hand written signatures have been used for some time to endorse financial transactions and legal contracts although little or no verification of signatures is done. This sets it apart from the other biometrics as it is well accepted method of authentication. Until more recently, only hidden Markov models were used for model construction. Ongoing research on signature verification has revealed that more accurate results can be achieved by combining results of multiple models. We also proposed to use combinations of multiple single variate models instead of single multi variate models which are currently being adapted by many systems. Apart from these, the proposed system is an attractive way for making financial transactions more secure and authenticate electronic documents as it can be easily integrated into existing transaction procedures and electronic communications