25 research outputs found

    Multilayer gmdh-neuro-fuzzy network based on extended neo-fuzzy neurons and its application in online facial expression recognition

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    Real-time image recognition is required in many important practical problems. Interaction with users in online mode requires flexibility and adaptability from applications. The Group Method of Data Handling (GMDH) allows changing the model structure and adjusting the system architecture to the characteristics of each task under consideration. Moreover, the approximating properties of neo-fuzzy neurons used as elements of the system provide the high recognition accuracy under conditions of short data samples. This paper proposes a multilayer GMDH-neuro-fuzzy network based on extended neo-fuzzy neurons. The learning algorithm has filtering and tracking properties, guarantees the required speed important for real-time applications. The effectiveness of the proposed system is confirmed for the human emotions recognition

    Industrial time series modelling by means of the neo-fuzzy neuron

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    Abstract—Industrial process monitoring and modelling represents a critical step in order to achieve the paradigm of Zero Defect Manufacturing. The aim of this paper is to introduce the Neo-Fuzzy Neuron method to be applied in industrial time series modelling. Its open structure and input independency provides fast learning and convergence capabilities, while assuring a proper accuracy and generalization in the modelled output. First, the auxiliary signals in the database are analyzed in order to find correlations with the target signal. Second, the Neo-Fuzzy Neuron is configured and trained according by means of the auxiliary signal, past instants and dynamics information of the target signal. The proposed method is validated by means of real data from a Spanish copper rod industrial plant, in which a critical signal regarding copper refrigeration process is modelled. The obtained results indicate the suitability of the Neo-Fuzzy Neuron method for industrial process modelling.Postprint (published version

    An Application of Kolmogorov's Superposition Theorem to Function Reconstruction in Higher Dimensions

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    In this thesis we present a Regularization Network approach to reconstruct a continuous function ƒ:[0,1]n→R from its function values ƒ(xj) on discrete data points xj, j=1,…,P. The ansatz is based on a new constructive version of Kolmogorov's superposition theorem. Typically, the numerical solution of mathematical problems underlies the so--called curse of dimensionality. This term describes the exponential dependency of the involved numerical costs on the dimensionality n. To circumvent the curse at least to some extend, typically higher regularity assumptions on the function ƒ are made which however are unrealistic in most cases. Therefore, we employ a representation of the function as superposition of one--dimensional functions which does not require higher smoothness assumptions on ƒ than continuity. To this end, a constructive version of Kolmogorov's superposition theorem which is based on D. Sprecher is adapted in such a manner that one single outer function Φ and a universal inner function ψ suffice to represent the function ƒ. Here, ψ is the extension of a function which was defined by M. Köppen on a dense subset of the real line. The proofs of existence, continuity, and monotonicity are presented in this thesis. To compute the outer function Φ, we adapt a constructive algorithm by Sprecher such that in each iteration step, depending on ƒ, an element of a sequence of univariate functions { Φr}r is computed. It will be shown that this sequence converges to a continuous limit Φ:R→R. This constructively proves Kolmogorov's superposition theorem with a single outer and inner function. Due to the fact that the numerical complexity to compute the outer function Φ by the algorithm grows exponentially with the dimensionality, we alternatively present a Regularization Network approach which is based on this representation. Here, the outer function is computed from discrete function samples (xj,ƒ(xj)), j=1,…,P. The model to reconstruct ƒ will be introduced in two steps. First, the outer function Φ is represented in a finite basis with unknown coefficients which are then determined by a variational formulation, i.e. by the minimization of a regularized empirical error functional. A detailed numerical analysis of this model shows that the dimensionality of ƒ is transformed by Kolmogorov's representation into oscillations of Φ. Thus, the use of locally supported basis functions leads to an exponential growth of the complexity since the spatial mesh resolution has to resolve the strong oscillations. Furthermore, a numerical analysis of the Fourier transform of Φ shows that the locations of the relevant frequencies in Fourier space can be determined a priori and are independent of ƒ. It also reveals a product structure of the outer function and directly motivates the definition of the final model. Therefore, Φ is replaced in the second step by a product of functions for which each factor is expanded in a Fourier basis with appropriate frequency numbers. Again, the coefficients in the expansions are determined by the minimization of a regularized empirical error functional. For both models, the underlying approximation spaces are developed by means of reproducing kernel Hilbert spaces and the corresponding norms are the respective regularization terms in the empirical error functionals. Thus, both approaches can be interpreted as Regularization Networks. However, it is important to note that the error functional for the second model is not convex and that nonlinear minimizers have to be used for the computation of the model parameters. A detailed numerical analysis of the product model shows that it is capable of reconstructing functions which depend on up to ten variables.Eine Anwendung von Kolmogorovs Superpositionen Theorem zur Funktionsrekonstruktion in höheren Dimensionen In der vorliegenden Arbeit wird ein Regularisierungsnetzwerk zur Rekonstruktion von stetigen Funktionen ƒ:[0,1]n→R vorgestellt, welches direkt auf einer neuen konstruktiven Version von Kolmogorovs Superpositionen Theorem basiert. Dabei sind lediglich die Funktionswerte ƒ(xj) an diskreten Datenpunktenxj, j=1,…,P bekannt. Typischerweise leidet die numerische Lösung mathematischer Probleme unter dem sogenannten Fluch der Dimension. Dieser Begriff beschreibt das exponentielle Wachstum der Komplexität des verwendeten Verfahrens mit der Dimension n. Um dies zumindest teilweise zu vermeiden, werden üblicherweise höhere Regularitätsannahmen an die Lösung des Problems gemacht, was allerdings häufig unrealistisch ist. Daher wird in dieser Arbeit eine Darstellung der Funktion ƒ als Superposition eindimensionaler Funktionen verwendet, welche keiner höheren Regularitätsannahmen als Stetigkeit bedarf. Zu diesem Zweck wird eine konstruktive Variante des Kolmogorov Superpositionen Theorems, welche auf D. Sprecher zurückgeht, so angepasst, dass nur eine äußere Funktion Φ sowie eine universelle innere Funktion ψ zur Darstellung von ƒ notwendig ist. Die Funktion ψ ist nach einer Definition von M. Köppen explizit und unabhängig von ƒ als Fortsetzung einer Funktion, welche auf einer Dichten Teilmenge der reellen Achse definiert ist, gegeben. Der fehlende Beweis von Existenz, Stetigkeit und Monotonie von ψ wird in dieser Arbeit geführt. Zur Berechnung der äußeren Funktion Φ wird ein iterativer Algorithmus von Sprecher so modifiziert, dass jeder Iterationsschritt, abhängig von ƒ, ein Element einer Folge univariater Funktionen{ Φr}r liefert. Es wird gezeigt werden, dass die Folge gegen einen stetigen Grenzwert Φ:R→R konvergiert. Dies liefert einen konstruktiven Beweis einer neuen Version des Kolmogorov Superpositionen Theorems mit einer äußeren und einer inneren Funktion. Da die numerische Komplexität des Algorithmus zur Berechnung von Φ exponentiell mit der Dimension wächst, stellen wir alternativ ein Regularisierungsnetzwerk, basierend auf dieser Darstellung, vor. Dabei wird die äußere Funktion aus gegebenen Daten (xj,ƒ(xj)), j=1,…,P berechnet. Das Modell zur Rekonstruktion von ƒ wird in zwei Schritten eingeführt. Zunächst wird zur Definition eines vorläufigen Modells die äußere Funktion, bzw. eine Approximation an Φ, in einer endlichen Basis mit unbekannten Koeffizienten dargestellt. Diese werden dann durch eine Variationsformulierung bestimmt, d.h. durch die Minimierung eines regularisierten empirischen Fehlerfunktionals. Eine detaillierte numerische Analyse zeigt dann, dass Kolmogorovs Darstellung die Dimensionalität von ƒ in Oszillationen von F transformiert. Somit ist die Verwendung von Basisfunktionen mit lokalem Träger nicht geeignet, da die räumliche Auflösung der Approximation die starken Oszillationen erfassen muss. Des Weiteren zeigt eine Analyse der Fouriertransformation von Φ, dass die relevanten Frequenzen, unabhängig von ƒ, a priori bestimmbar sind, und dass die äußere Funktion Produktstruktur aufweist. Dies motiviert die Definition des endgültigen Modells. Dazu wird Φ nun durch ein Produkt von Funktionen ersetzt und jeder Faktor in einer Fourierbasis entwickelt. Die Koeffizienten werden ebenfalls durch Minimierung eines regularisierten empirischen Fehlerfunktionals bestimmt. Für beide Modelle wird ein theoretischer Rahmen in Form von Hilberträumen mit reproduzierendem Kern entwickelt. Die zugehörigen Normen bilden dabei jeweils den Regularisierungsterm der entsprechenden Fehlerfunktionale. Somit können beide Ansätze als Regularisierungsnetzwerke interpretiert werden. Allerdings ist zu beachten, dass das Fehlerfunktional für den Produktansatz nicht konvex ist und nichtlineare Minimierungsverfahren zur Berechnung der Koeffizienten notwendig sind. Weitere ausführliche numerische Tests zeigen, dass dieses Modell in der Lage ist Funktionen zu rekonstruieren welche von bis zu zehn Variablen abhängen

    Contributions to industrial process condition forecasting applied to copper rod manufacturing process

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    Ensuring reliability and robustness of operation is one of the main concerns in industrial anufacturing processes , dueto the ever-increasing demand for improvements over the cost and quality ofthe processes outcome. In this regard , a deviation from the nominal operating behaviours implies a divergence from the optimal condition specification, anda misalignment from the nominal product quality, causing a critica! loss of potential earnings . lndeed, since a decade ago, the industrial sector has been carried out a significant effortAsegurar la fiabilidad y la robustez es uno de los principales objetivos en la monitorización de los procesos industriales, ya que estos cada vez se encuentran sometidos a demandas de producción más elevadas a la vez que se deben bajar costes de fabricación manteniendo la calidad del producto final. En este sentido, una desviación de la operación del proceso implica una divergencia de los parámetros óptimos preestablecidos, lo que conlleva a una desviación respecto la calidad nominal del producto final, causando así un rechazo de dicho producto y una perdida en costes para la empresa. De hecho, tanto es así, que desde hace más de una década el sector industrial ha dedicado un esfuerzo considerable a la implantación de metodologías de monitorización inteligente. Dichos métodos son capaces extraer información respecto a la condición de las diferentes maquinarias y procesos involucrados en el proceso de fabricación. No obstante, esta información extraída corresponde al estado actual del proceso. Por lo que obtener información respecto a la condición futura de dicho proceso representa una mejora significativa para poder ganar tiempo de respuesta para la detección y corrección de desviaciones en la operación de dicho proceso. Por lo tanto, la combinación del conocimiento futuro del comportamiento del proceso con la consecuente evaluación de la condición del mismo, es un objetivo a cumplir para la definición de las nuevas generaciones de sistemas de monitorización de procesos industriales. En este sentido, la presente tesis tiene como objetivo la propuesta de metodologías para evaluar la condición, actual y futura, de procesos industriales. Dicha metodología debe estimar la condición de forma fiable y con una alta resolución. Por lo tanto, en esta tesis se pretende extraer la información de la condición futura a partir de un modelado, basado en series temporales, de las señales críticas del proceso, para después, en base a enfoques no lineales de preservación de la topología, fusionar dichas señales proyectadas a futuro para conocer la condición. El rendimiento y la bondad de las metodologías propuestas en la tesis han sido validadas mediante su aplicación en un proceso industrial real, concretamente, con datos de una planta de fabricación de alambrón de cobre

    A therapeutic elimination of “belief” and “desire” from causal accounts of action

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    This introduction sets out the objectives, topic, method and structure of this thesis. I describe philosophical folk psychology and the roles that it is presumed to play in action choice, interpersonal understanding and reason giving. Philosophical folk psychology – particularly when expressed as belief-desire psychology – is suggested by some as a way to describe all three of these phenomena under a single model. I argue, however, that this comes at the cost of a number of unwarranted commitments which give rise to philosophical problems. I introduce a handful of influential thinkers who have advanced folk psychological positions and also some contemporary examples of philosophers addressing problems arising directly from it. I then introduce the diagnostic-therapeutic intent of this thesis, grounded in a reading of Wittgenstein’s approach to philosophy through the later work of Gordon Baker. Thereafter I set out the two-part structure of the thesis and briefly outline the chapters

    A Posture Sequence Learning System for an Anthropomorphic Robotic Hand

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    The paper presents a cognitive architecture for posture learning of an anthropomorphic robotic hand. Our approach is aimed to allow the robotic system to perform complex perceptual operations, to interact with a human user and to integrate the perceptions by a cognitive representation of the scene and the observed actions. The anthropomorphic robotic hand imitates the gestures acquired by the vision system in order to learn meaningful movements, to build its knowledge by different conceptual spaces and to perform complex interaction with the human operator

    Contribuitions and developments on nonintrusive load monitoring

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    Energy efficiency is a key subject in our present world agenda, not only because of greenhouse gas emissions, which contribute to global warming, but also because of possible supply interruptions. In Brazil, energy wastage in the residential market is estimated to be around 15%. Previous studies have indicated that the most savings were achieved with specific appliance, electricity consumption feedback, which caused behavioral changes and encouraged consumers to pursue energy conservation. Nonintrusive Load Monitoring (NILM) is a relatively new term. It aims to disaggregate global consumption at an appliance level, using only a single point of measurement. Various methods have been suggested to infer when appliances are turned on and off, using the analysis of current and voltage aggregated waveforms. Within this context, we aim to provide a methodology for NILM to determine which sets of electrical features and feature extraction rates, obtained from aggregated household data, are essential to preserve equivalent levels of accuracy; thus reducing the amount of data that needs to be transferred to, and stored on, cloud servers. As an addendum to this thesis, a Brazilian appliance dataset, sampled from real appliances, was developed for future NILM developments and research. Beyond that, a low-cost NILM smart meter was developed to encourage consumers to change their habits to more sustainable methods.Eficiência energética é um assunto essencial na agenda mundial. No Brasil, o desperdício de energia no setor residencial é estimado em 15%. Estudos indicaram que maiores ganhos em eficiência são conseguidos quando o usuário recebe as informações de consumo detalhadas por cada aparelho, provocando mudanças comportamentais e incentivando os consumidores na conservação de energia. Monitoramento não intrusivo de cargas (NILM da sigla em inglês) é um termo relativamente novo. A sua finalidade é inferir o consumo de um ambiente até observar os consumos individualizados de cada equipamento utilizando-se de apenas um único ponto de medição. Métodos sofisticados têm sido propostos para inferir quando os aparelhos são ligados e desligados em um ambiente. Dentro deste contexto, este trabalho apresenta uma metodologia para a definição de um conjunto mínimo de características elétricas e sua taxa de extração que reduz a quantidade de dados a serem transmitidos e armazenados em servidores de processamento de dados, preservando níveis equivalentes de acurácia. São utilizadas diferentes técnicas de aprendizado de máquina visando à caracterização e solução do problema. Como adendo ao trabalho, apresenta-se um banco de dados de eletrodomésticos brasileiros, com amostras de equipamentos nacionais para desenvolvimentos futuros em NILM, além de um medidor inteligente de baixo custo para desagregação de cargas, visando tornar o consumo de energia mais sustentável

    Power Electronics and Energy Management for Battery Storage Systems

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    The deployment of distributed renewable generation and e-mobility systems is creating a demand for improved dynamic performance, flexibility, and resilience in electrical grids. Various energy storages, such as stationary and electric vehicle batteries, together with power electronic interfaces, will play a key role in addressing these requests thanks to their enhanced functionality, fast response times, and configuration flexibility. For the large-scale implementation of this technology, the associated enabling developments are becoming of paramount importance. These include energy management algorithms; optimal sizing and coordinated control strategies of different storage technologies, including e-mobility storage; power electronic converters for interfacing renewables and battery systems, which allow for advanced interactions with the grid; and increase in round-trip efficiencies by means of advanced materials, components, and algorithms. This Special Issue contains the developments that have been published b researchers in the areas of power electronics, energy management and battery storage. A range of potential solutions to the existing barriers is presented, aiming to make the most out of these emerging technologies
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