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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Hybrid Machine and Deep Learning-based Cyberattack Detection and Classification in Smart Grid Networks

Aribisala, Adedayo 01 May 2022 (has links)
Power grids have rapidly evolved into Smart grids and are heavily dependent on Supervisory Control and Data Acquisition (SCADA) systems for monitoring and control. However, this evolution increases the susceptibility of the remote (VMs, VPNs) and physical interfaces (sensors, PMUs LAN, WAN, sub-stations power lines, and smart meters) to sophisticated cyberattacks. The continuous supply of power is critical to power generation plants, power grids, industrial grids, and nuclear grids; the halt to global power could have a devastating effect on the economy's critical infrastructures and human life. Machine Learning and Deep Learning-based cyberattack detection modeling have yielded promising results when combined as a Hybrid with an Intrusion Detection System (IDS) or Host Intrusion Detection Systems (HIDs). This thesis proposes two cyberattack detection techniques; one that leverages Machine Learning algorithms and the other that leverages Artificial Neural networks algorithms to classify and detect the cyberattack data held in a foundational dataset crucial to network intrusion detection modeling. This thesis aimed to analyze and evaluate the performance of a Hybrid Machine Learning (ML) and a Hybrid Deep Learning (DL) during ingress packet filtering, class classification, and anomaly detection on a Smart grid network.
22

INTELLIGENT MULTIPLE-OBJECTIVE PROACTIVE ROUTING IN MANET WITH PREDICTIONS ON DELAY, ENERGY, AND LINK LIFETIME

Guo, Zhihao January 2008 (has links)
No description available.
23

Predicting PV self-consumption in villas with machine learning

GALLI, FABIAN January 2021 (has links)
In Sweden, there is a strong and growing interest in solar power. In recent years, photovoltaic (PV) system installations have increased dramatically and a large part are distributed grid connected PV systems i.e. rooftop installations. Currently the electricity export rate is significantly lower than the import rate which has made the amount of self-consumed PV electricity a critical factor when assessing the system profitability. Self-consumption (SC) is calculated using hourly or sub-hourly timesteps and is highly dependent on the solar patterns of the location of interest, the PV system configuration and the building load. As this varies for all potential installations it is difficult to make estimations without having historical data of both load and local irradiance, which is often hard to acquire or not available. A method to predict SC using commonly available information at the planning phase is therefore preferred.  There is a scarcity of documented SC data and only a few reports treating the subject of mapping or predicting SC. Therefore, this thesis is investigating the possibility of utilizing machine learning to create models able to predict the SC using the inputs: Annual load, annual PV production, tilt angle and azimuth angle of the modules, and the latitude. With the programming language Python, seven models are created using regression techniques, using real load data and simulated PV data from the south of Sweden, and evaluated using coefficient of determination (R2) and mean absolute error (MAE). The techniques are Linear Regression, Polynomial regression, Ridge Regression, Lasso regression, K-Nearest Neighbors (kNN), Random Forest, Multi-Layer Perceptron (MLP), as well as the only other SC prediction model found in the literature. A parametric analysis of the models is conducted, removing one variable at a time to assess the model’s dependence on each variable.  The results are promising, with five out of eight models achieving an R2 value above 0.9 and can be considered good for predicting SC. The best performing model, Random Forest, has an R2 of 0.985 and a MAE of 0.0148. The parametric analysis also shows that while more input data is helpful, using only annual load and PV production is sufficient to make good predictions. This can only be stated for model performance for the southern region of Sweden, however, and are not applicable to areas outside the latitudes or country tested. / I Sverige finns ett starkt och växande intresse för solenergi. De senaste åren har antalet solcellsanläggningar ökat dramatiskt och en stor del är distribuerade nätanslutna solcellssystem, dvs takinstallationer. För närvarande är elexportpriset betydligt lägre än importpriset, vilket har gjort mängden egenanvänd solel till en kritisk faktor vid bedömningen av systemets lönsamhet. Egenanvändning (EA) beräknas med tidssteg upp till en timmes längd och är i hög grad beroende av solstrålningsmönstret för platsen av intresse, PV-systemkonfigurationen och byggnadens energibehov. Eftersom detta varierar för alla potentiella installationer är det svårt att göra uppskattningar utan att ha historiska data om både energibehov och lokal solstrålning, vilket ofta inte är tillgängligt. En metod för att förutsäga EA med allmän tillgänglig information är därför att föredra.  Det finns en brist på dokumenterad EA-data och endast ett fåtal rapporter som behandlar kartläggning och prediktion av EA. I denna uppsats undersöks möjligheten att använda maskininlärning för att skapa modeller som kan förutsäga EA. De variabler som ingår är årlig energiförbrukning, årlig solcellsproduktion, lutningsvinkel och azimutvinkel för modulerna och latitud. Med programmeringsspråket Python skapas sju modeller med hjälp av olika regressionstekniker, där energiförbruknings- och simulerad solelproduktionsdata från södra Sverige används. Modellerna utvärderas med hjälp av determinationskoefficienten (R2) och mean absolute error (MAE). Teknikerna som används är linjär regression, polynomregression, Ridge regression, Lasso regression, K-nearest neighbor regression, Random Forest regression, Multi-Layer Perceptron regression. En additionell linjär regressions-modell skapas även med samma metodik som används i en tidigare publicerad rapport. En parametrisk analys av modellerna genomförs, där en variabel exkluderas åt gången för att bedöma modellens beroende av varje enskild variabel.  Resultaten är mycket lovande, där fem av de åtta undersökta modeller uppnår ett R2-värde över 0,9. Den bästa modellen, Random Forest, har ett R2 på 0,985 och ett MAE på 0,0148. Den parametriska analysen visar också att även om ingångsdata är till hjälp, är det tillräckligt att använda årlig energiförbrukning och årlig solcellsproduktion för att göra bra förutsägelser. Det måste dock påpekas att modellprestandan endast är tillförlitlig för södra Sverige, från var beräkningsdata är hämtad, och inte tillämplig för områden utanför de valda latituderna eller land.
24

PV self-consumption: Regression models and data visualization

Tóth, Martos January 2022 (has links)
In Sweden the installed capacity of the residential PV systems is increasing every year. The lack of feed-in-tariff-scheme makes the techno-economic optimization of the PV systems mainly based on the self-consumption. The calculation of this parameter involves hourly building loads and hourly PV generation. This data cannot be obtained easily from households. A predictive model based on already available data would be preferred and needed in this case. The already available machine learning models can be suitable and have been tested but the amount of literature in this topic is fairly low. The machine learning models are using a dataset which includes real measurement data of building loads and simulated PV generation data and the calculated self-consumption data based on these two inputs. The simulation of PV generation can be based on Typical Meteorological Year (TMY) weather file or on measured weather data. The TMY file can be generated quicker and more easily, but it is only spatially matched to the building load, while the measured data is matched temporally and spatially. This thesis investigates if the usage of TMY file leads to any major impact on the performance of the regression models by comparing it to the measured weather file model. In this model the buildings are single-family houses from south Sweden region.  The different building types can have different load profiles which can affect the performance of the model. Because of the different load profiles, the effect of using TMY file may have more significant impact. This thesis also compares the impact of the TMY file usage in the case of multifamily houses and also compares the two building types by performance of the machine learning models. The PV and battery prices are decreasing from year to year. The subsidies in Sweden offer a significant tax credit on battery investments with PV systems. This can make the batteries profitable. Lastly this thesis evaluates the performance of the machine learning models after adding the battery to the system for both TMY and measured data. Also, the optimal system is predicted based on the self-consumption, PV generation and battery size.  The models have high accuracy, the random forest model is above 0.9 R2for all cases. The results confirm that using the TMY file only leads to marginal errors, and it can be used for the training of the models. The battery model has promising results with above 0.9 R2 for four models: random forest, k-NN, MLP and polynomial. The prediction of the optimal system model has promising results as well for the polynomial model with 18% error in predicted payback time compared to the reference. / I Sverige ökar den installerade kapaciteten för solcellsanläggningarna för bostäder varje år. Bristen på inmatningssystem gör att den tekniska ekonomiska optimeringen av solcellssystemen huvudsakligen bygger på egen konsumtion. Beräkningen av denna parameter omfattar byggnadsbelastningar per timme och PV-generering per timme. Dessa uppgifter kan inte lätt erhållas från hushållen. En prediktiv modell baserad på redan tillgängliga data skulle vara att föredra och behövas i detta fall. De redan tillgängliga maskininlärningsmodellerna kan vara lämpliga och redan testade men mängden litteratur i detta ämne är ganska låg. Maskininlärningsmodellerna använder en datauppsättning som inkluderar verkliga mätdata från byggnader och simulerad PV-genereringsdata och den beräknade egenförbrukningsdata baserad på dessa två indata. Simuleringen av PV-generering kan baseras på väderfilen Typical Meteorological Year (TMY) eller på uppmätta väderdata. TMY-filen kan genereras snabbare och enklare, men den anpassas endast rumsligt till byggnadsbelastningen, medan uppmätta data är temporärt och rumsligt. Denna avhandling undersöker om användningen av TMY-fil leder till någon större påverkan på prestandan genom att jämföra den med den uppmätta väderfilsmodellen. I denna modell är byggnaderna småhus från södra Sverige. De olika byggnadstyperna kan ha olika belastningsprofiler vilket kan påverka modellens prestanda. På grund av dessa olika belastningsprofiler kan effekten av att använda TMY-fil ha mer betydande inverkan. Den här avhandlingen jämför också effekten av TMY-filanvändningen i fallet med flerfamiljshus och jämför också de två byggnadstyperna efter prestanda för maskininlärningsmodellerna. PV- och batteripriserna minskar från år till år. Subventionerna i Sverige ger en betydande skattelättnad på batteriinvesteringar med solcellssystem. Detta kan göra batterierna lönsamma. Slutligen utvärderar denna avhandling prestandan för maskininlärningsmodellerna efter att ha lagt till batteriet i systemet för både TMY och uppmätta data. Det optimala systemet förutsägs också baserat på egen förbrukning, årlig byggnadsbelastning, årlig PV-generering och batteristorlek. Modellerna har hög noggrannhet, den slumpmässiga skogsmodellen är över 0,9 R2 för alla fall. Resultaten bekräftar att användningen av TMY-filen endast leder till marginella fel, och den kan användas för träning av modellerna. Batterimodellen har lovande resultat med över 0,9 R2 för fyra modeller: random skog, k-NN, MLP och polynom. Förutsägelsen av den optimala systemmodellen har också lovande resultat för polynommodellen med 18 % fel i förutspådd återbetalningstid jämfört med referensen.
25

Transient engine model for calibration using two-stage regression approach

Khan, Muhammad Alam Z. January 2011 (has links)
Engine mapping is the process of empirically modelling engine behaviour as a function of adjustable engine parameters, predicting the output of the engine. The aim is to calibrate the electronic engine controller to meet decreasing emission requirements and increasing fuel economy demands. Modern engines have an increasing number of control parameters that are having a dramatic impact on time and e ort required to obtain optimal engine calibrations. These are further complicated due to transient engine operating mode. A new model-based transient calibration method has been built on the application of hierarchical statistical modelling methods, and analysis of repeated experiments for the application of engine mapping. The methodology is based on two-stage regression approach, which organise the engine data for the mapping process in sweeps. The introduction of time-dependent covariates in the hierarchy of the modelling led to the development of a new approach for the problem of transient engine calibration. This new approach for transient engine modelling is analysed using a small designed data set for a throttle body inferred air ow phenomenon. The data collection for the model was performed on a transient engine test bed as a part of this work, with sophisticated software and hardware installed on it. Models and their associated experimental design protocols have been identi ed that permits the models capable of accurately predicting the desired response features over the whole region of operability. Further, during the course of the work, the utility of multi-layer perceptron (MLP) neural network based model for the multi-covariate case has been demonstrated. The MLP neural network performs slightly better than the radial basis function (RBF) model. The basis of this comparison is made on assessing relevant model selection criteria, as well as internal and external validation ts. Finally, the general ability of the model was demonstrated through the implementation of this methodology for use in the calibration process, for populating the electronic engine control module lookup tables.
26

Redes neurais e algoritmos genéticos no estudo quimiossistemático da família Asteraceae / Neural Network and Genetic Algorithms in the Chemosystematic study of Asteraceae Family

Correia, Mauro Vicentini 16 March 2010 (has links)
No presente trabalho duas metodologias da área de inteligência artificial (Redes Neurais e Algoritmos Genéticos) foram utilizadas para realizar um estudo Quimiossistemático da família Asteraceae. A família Asteraceae é uma das maiores famílias entre as Angiospermas, conta com aproximadamente 24.000 espécies. As espécies da família produzem grande diversidade de metabólitos secundários, entre os quais merecem destaque os terpenóides, poliacetilenos, flavonóides e cumarinas. Para um melhor entendimento da diversidade química da família construiu-se um Banco de Dados com as ocorrências de doze classes de metabólitos (monoterpenos, sesquiterpenos, sesquiterpenos lactonizados, diterpenos, triterpenos, cumarinas, flavonóides, poliacetilenos, benzofuranos, benzopiranos, acetofenonas e fenilpropanóides) produzidos pelas espécies da família. A partir desse banco três diferentes estudos foram realizados. No primeiro estudo, utilizando os mapas auto-organizáveis de Kohonen e o banco de dados químico classificado segundo duas das mais recentes filogenias da família foi possível realizar com sucesso separações de tribos e gêneros da família Asteraceae. Também foi possível indicar que a informação química concorda mais com a filogenia de Funk (Funk et al. 2009) do que com a filogenia de Bremer (Bremer 1994, 1996). No estudo seguinte, onde se objetivou a criação de modelos de previsão dos números de ocorrências das doze classes de metabólitos, utilizando o perceptron de múltiplas camadas com algoritmo de retropropagação de erro, o resultado foi insatisfatório. Apesar de em algumas classes de metabólitos a fase de treino da rede apresentar resultados satisfatórios, a fase de teste mostrou que os modelos criados não são capazes de realizar previsão para dados aos quais eles não foram submetidos na fase de treino, e portanto não são modelos adequados para realizar previsões. Finalmente, o terceiro estudo consistiu na criação de modelos de regressão linear utilizando como método de seleção de variáveis os algoritmos genéticos. Nesse estudo foi possível indicar que os monoterpenos e os sesquiterpenos são bastante relacionados biossinteticamente, também foi possível indicar que existem relações biossintéticas entre monoterpenos e diterpenos e entre sesquiterpenos e triterpenos / In this study two methods of artificial intelligence (neural network and genetic algorithms) were used to work out a Chemosystematic study of the Asteraceae family. The family Asteraceae is one of the largest families among the Angiosperms, having about 24,000 species. The species of the family produce a large diversity of secondary metabolites, and some worth mentioning are the terpenoids, polyacetylenes, flavonoids and coumarins. For a better understanding of the chemical diversity of the family a database was built up with the occurrences of twelve classes of metabolites (monoterpenes, sesquiterpenes, lactonizadossesquiterpenes, diterpenes, triterpenes, coumarins, flavonoids, polyacetylenes, Benzofurans, benzopyrans, acetophenones and phenylpropanoids) produced by species of the family. From this database three different studies were conducted. In the first study, using the Kohonen self-organized map and the chemical data classified according to two of the most recent phylogenies of the family, it was possible to successfully separatethe tribes and genera of the Asteraceae family. It was also possible to indicate that the chemical information agrees with the phylogeny of Funk (Funk et al. 2009) than with the phylogeny of Bremer (Bremer 1994, 1996). In the next study, which aims at creating models to predict the number of occurrences of the twelve classes of metabolites using multi-layer perceptron with backpropagation algorithm error, the result was found unsatisfactory. Although in some classes of metabolites the training phase of the network has satisfactory results, the test phase showed that the models created are not able to make prevision for data to which they were submitted in the training phase and thus are not suitable models for predictions. Finally, the third study was the creation of linear regression models using a genetic algorithm method of variable selection. This study could indicate that the monoterpenes and sesquiterpenes are closely related biosynthetically, and was also possible to indicate that there are biosynthetic relations between monoterpenes and diterpenes and between sesquiterpenes and triterpenes
27

Undersökning om hjulmotorströmmar kan användas som alternativ metod för kollisiondetektering i autonoma gräsklippare. : Klassificering av hjulmotorströmmar med KNN och MLP. / Investigation if wheel motor currents can be used as an alternative method for collision detection in robotic lawn mowers

Bertilsson, Tobias, Johansson, Romario January 2019 (has links)
Purpose – The purpose of the study is to expand the knowledge of how wheel motor currents can be combined with machine learning to be used in a collision detection system for autonomous robots, in order to decrease the number of external sensors and open new design opportunities and lowering production costs. Method – The study is conducted with design science research where two artefacts are developed in a cooperation with Globe Tools Group. The artefacts are evaluated in how they categorize data given by an autonomous robot in the two categories collision and non-collision. The artefacts are then tested by generated data to analyse their ability to categorize. Findings – Both artefacts showed a 100 % accuracy in detecting the collisions in the given data by the autonomous robot. In the second part of the experiment the artefacts show that they have different decision boundaries in how they categorize the data, which will make them useful in different applications. Implications – The study contributes to an expanding knowledge in how machine learning and wheel motor currents can be used in a collision detection system. The results can lead to lowering production costs and opening new design opportunities. Limitations – The data used in the study is gathered by an autonomous robot which only did frontal collisions on an artificial lawn. Keywords – Machine learning, K-Nearest Neighbour, Multilayer Perceptron, collision detection, autonomous robots, Collison detection based on current. / Syfte – Studiens syfte är att utöka kunskapen om hur hjulmotorstömmar kan kombineras med maskininlärning för att användas vid kollisionsdetektion hos autonoma robotar, detta för att kunna minska antalet krävda externa sensorer hos dessa robotar och på så sätt öppna upp design möjligheter samt minska produktionskostnader Metod – Studien genomfördes med design science research där två artefakter utvecklades i samarbete med Globe Tools Group. Artefakterna utvärderades sedan i hur de kategoriserade kollisioner utifrån en given datamängd som genererades från en autonom gräsklippare. Studiens experiment introducerade sedan in data som inte ingick i samma datamängd för att se hur metoderna kategoriserade detta. Resultat – Artefakterna klarade med 100% noggrannhet att detektera kollisioner i den giva datamängden som genererades. Dock har de två olika artefakterna olika beslutsregioner i hur de kategoriserar datamängderna till kollision samt icke-kollisioner, vilket kan ge dom olika användningsområden Implikationer – Examensarbetet bidrar till en ökad kunskap om hur maskininlärning och hjulmotorströmmar kan användas i ett kollisionsdetekteringssystem. Studiens resultat kan bidra till minskade kostnader i produktion samt nya design möjligheter Begränsningar – Datamängden som användes i studien samlades endast in av en autonom gräsklippare som gjorde frontalkrockar med underlaget konstgräs. Nyckelord – Maskininlärning, K-nearest neighbor, Multi-layer perceptron, kollisionsdetektion, autonoma robotar
28

Um estudo sobre a extraÃÃo de caracterÃsticas e a classificaÃÃo de imagens invariantes à rotaÃÃo extraÃdas de um sensor industrial 3D / A study on the extraction of characteristics and the classification of invariant images through the rotation of an 3D industrial sensor

Rodrigo Dalvit Carvalho da Silva 08 May 2014 (has links)
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / Neste trabalho, à discutido o problema de reconhecimento de objetos utilizando imagens extraÃdas de um sensor industrial 3D. NÃs nos concentramos em 9 extratores de caracterÃsticas, dos quais 7 sÃo baseados nos momentos invariantes (Hu, Zernike, Legendre, Fourier-Mellin, Tchebichef, Bessel-Fourier e Gaussian-Hermite), um outro à baseado na Transformada de Hough e o Ãltimo na anÃlise de componentes independentes, e, 4 classificadores, Naive Bayes, k-Vizinhos mais PrÃximos, MÃquina de Vetor de Suporte e Rede Neural Artificial-Perceptron Multi-Camadas. Para a escolha do melhor extrator de caracterÃsticas, foram comparados os seus desempenhos de classificaÃÃo em termos de taxa de acerto e de tempo de extraÃÃo, atravÃs do classificador k-Vizinhos mais PrÃximos utilizando distÃncia euclidiana. O extrator de caracterÃsticas baseado nos momentos de Zernike obteve as melhores taxas de acerto, 98.00%, e tempo relativamente baixo de extraÃÃo de caracterÃsticas, 0.3910 segundos. Os dados gerados a partir deste, foram apresentados a diferentes heurÃsticas de classificaÃÃo. Dentre os classificadores testados, o classificador k-Vizinhos mais PrÃximos, obteve a melhor taxa mÃdia de acerto, 98.00% e, tempo mÃdio de classificaÃÃo relativamente baixo, 0.0040 segundos, tornando-se o classificador mais adequado para a aplicaÃÃo deste estudo. / In this work, the problem of recognition of objects using images extracted from a 3D industrial sensor is discussed. We focus in 9 feature extractors (where seven are based on invariant moments -Hu, Zernike, Legendre, Fourier-Mellin, Tchebichef, BesselâFourier and Gaussian-Hermite-, another is based on the Hough transform and the last one on independent component analysis), and 4 classifiers (Naive Bayes, k-Nearest Neighbor, Support Vector machines and Artificial Neural Network-Multi-Layer Perceptron). To choose the best feature extractor, their performance was compared in terms of classification accuracy rate and extraction time by the k-nearest neighbors classifier using euclidean distance. The feature extractor based on Zernike moments, got the best hit rates, 98.00 %, and relatively low time feature extraction, 0.3910 seconds. The data generated from this, were presented to different heuristic classification. Among the tested classifiers, the k-nearest neighbors classifier achieved the highest average hit rate, 98.00%, and average time of relatively low rank, 0.0040 seconds, thus making it the most suitable classifier for the implementation of this study.
29

Multi-layer Perceptron Error Surfaces: Visualization, Structure and Modelling

Gallagher, Marcus Reginald Unknown Date (has links)
The Multi-Layer Perceptron (MLP) is one of the most widely applied and researched Artificial Neural Network model. MLP networks are normally applied to performing supervised learning tasks, which involve iterative training methods to adjust the connection weights within the network. This is commonly formulated as a multivariate non-linear optimization problem over a very high-dimensional space of possible weight configurations. Analogous to the field of mathematical optimization, training an MLP is often described as the search of an error surface for a weight vector which gives the smallest possible error value. Although this presents a useful notion of the training process, there are many problems associated with using the error surface to understand the behaviour of learning algorithms and the properties of MLP mappings themselves. Because of the high-dimensionality of the system, many existing methods of analysis are not well-suited to this problem. Visualizing and describing the error surface are also nontrivial and problematic. These problems are specific to complex systems such as neural networks, which contain large numbers of adjustable parameters, and the investigation of such systems in this way is largely a developing area of research. In this thesis, the concept of the error surface is explored using three related methods. Firstly, Principal Component Analysis (PCA) is proposed as a method for visualizing the learning trajectory followed by an algorithm on the error surface. It is found that PCA provides an effective method for performing such a visualization, as well as providing an indication of the significance of individual weights to the training process. Secondly, sampling methods are used to explore the error surface and to measure certain properties of the error surface, providing the necessary data for an intuitive description of the error surface. A number of practical MLP error surfaces are found to contain a high degree of ultrametric structure, in common with other known configuration spaces of complex systems. Thirdly, a class of global optimization algorithms is also developed, which is focused on the construction and evolution of a model of the error surface (or search spa ce) as an integral part of the optimization process. The relationships between this algorithm class, the Population-Based Incremental Learning algorithm, evolutionary algorithms and cooperative search are discussed. The work provides important practical techniques for exploration of the error surfaces of MLP networks. These techniques can be used to examine the dynamics of different training algorithms, the complexity of MLP mappings and an intuitive description of the nature of the error surface. The configuration spaces of other complex systems are also amenable to many of these techniques. Finally, the algorithmic framework provides a powerful paradigm for visualization of the optimization process and the development of parallel coupled optimization algorithms which apply knowledge of the error surface to solving the optimization problem.
30

Réseaux de neurones, SVM et approches locales pour la prévision de séries temporelles / No available

Cherif, Aymen 16 July 2013 (has links)
La prévision des séries temporelles est un problème qui est traité depuis de nombreuses années. On y trouve des applications dans différents domaines tels que : la finance, la médecine, le transport, etc. Dans cette thèse, on s’est intéressé aux méthodes issues de l’apprentissage artificiel : les réseaux de neurones et les SVM. On s’est également intéressé à l’intérêt des méta-méthodes pour améliorer les performances des prédicteurs, notamment l’approche locale. Dans une optique de diviser pour régner, les approches locales effectuent le clustering des données avant d’affecter les prédicteurs aux sous ensembles obtenus. Nous présentons une modification dans l’algorithme d’apprentissage des réseaux de neurones récurrents afin de les adapter à cette approche. Nous proposons également deux nouvelles techniques de clustering, la première basée sur les cartes de Kohonen et la seconde sur les arbres binaires. / Time series forecasting is a widely discussed issue for many years. Researchers from various disciplines have addressed it in several application areas : finance, medical, transportation, etc. In this thesis, we focused on machine learning methods : neural networks and SVM. We have also been interested in the meta-methods to push up the predictor performances, and more specifically the local models. In a divide and conquer strategy, the local models perform a clustering over the data sets before different predictors are affected into each obtained subset. We present in this thesis a new algorithm for recurrent neural networks to use them as local predictors. We also propose two novel clustering techniques suitable for local models. The first is based on Kohonen maps, and the second is based on binary trees.

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