The term Rogue Trading is defined as the activity of someone at a financial organisation losing a large amount of money in bad or illegal transactions and trying to hide this. The activity of Rogue traders exposes financial organisations to huge risks and may lead to the organisation collapsing, which will affect other stakeholders like, for example, the customers. In order to detect potential Rogue Trading cases, Control Systems that monitor the employees and the positions they take on financial markets must exist. In this study, a two-step control system is suggested to monitor the margins on Foreign exchange (FX) Forwards traded by employees at the Swedish bank Skandinaviska Enskilda Banken (SEB). The first step in the control system uses a Deep Learning neural network trained on transactional data to predict the margin. The errors of the predictions versus the actual values are then in the second step of the control system used to find outliers which should be flagged for further investigation due to a too high deviation. The results show that the model hopefully can decrease the number of false positives yielded by the current Control Systems at SEB and thus reduce manual inspection of flagged transactions. / Termen Rouge Trading definieras som en aktivitet där någon på en finansiell institution förlorar stora mängder pengar i dåliga eller illegala transaktioner och försöker dölja detta. Detta är något som skapar enorma risker för finansiella institutioner och som kan förorsaka organisationens kollaps, som kan påverka intressenter som till exempel kunder. För att upptäcka potentiella företeelser av Rouge Trading så måste kontrollsystem som övervakar anställda och deras positioner existera. I denna studie föreslås och presenteras ett tvåstegs-system för att övervaka marginaler vid terminsaffärer i utländsk valuta vid Skandinaviska Enskilda Banken (SEB). Det första steget i kontrollsystemet använder ett neuralt närverk tränat på data från transaktioner för att prediktera en marginal. Differenserna mellan prediktionen och det faktiska värdet används för att finna outliers vilka borde flaggas för vidare undersökning. Resultaten visar att modellen förhoppningsvis kan minska antalet falska positiva som det nuvarande kontrollsystemet ger på SEB, något som således kan minska den manuella inspektionen av flaggade transaktioner.

Graças aos avanços tecnológicos nas áreas da computação, eletrônica embarcada e mecatrônica a robótica está cada vez mais presente no cotidiano da pessoas. Nessas últimas décadas, uma infinidade de ferramentas e métodos foram desenvolvidos no campo da Robótica Móvel. Um exemplo disso são os sistemas inteligentes embarcados nos veículos de passeio. Tais sistemas auxiliam na condução através de sensores que recebem informações do ambiente e algoritmos que analisam os dados e tomam decisões para realizar uma determinada tarefa, como por exemplo estacionar um carro. Este trabalho tem por objetivo apresentar estudos realizados no desenvolvimento de um controlador inteligente capaz de estacionar um veículo simulado em vagas paralelas, na qual seja possível entrar com uma única manobra. Para isso, foi necessário realizar estudos envolvendo a modelagem de ambientes, cinemática veicular e sensores, os quais foram implementados em um ambiente de simulação desenvolvido em C# com o Visual Studio 2008. Em seguida é realizado um estudo sobre as três etapas do estacionamento, que consistem em procurar uma vaga, posicionar o veículo e manobrá-lo. Para realizar a manobra foi adotada a trajetória em S desenvolvida e muito utilizada em outros trabalhos encontrados na literatura da área. A manobra consiste em posicionar corretamente duas circunferências com um raio de esterçamento do veículo. Sendo assim, foi utilizado um controlador robusto baseado em aprendizado supervisionado utilizando Redes Neurais Artificiais (RNA), pois esta abordagem apresenta grande robustez com relação à presença de ruídos no sistema. Este controlador recebe dados de dois sensores laser (um fixado na frente do veículo e o outro na parte traseira), da odometria e de orientação de um sensor inercial. Os dados adquiridos desses sensores e a etapa da manobra em que o veículo está, servem de entrada para o controlador. Este é capaz de interpretar tais dados e responder a esses estímulos de forma correta em aproximadamente 99% dos casos. Os resultados de treinamento e de simulação se mostraram muito satisfatórios, permitindo que o carro controlador pela RNA pudesse estacionar corretamente em uma vaga paralela. / Thanks to technological advances in the fields of computer science, embedded electronics and mechatronics, robotics is increasingly more present in people\'s lives. On the past few decades a great variety of tools and methods were developed in the Mobile Robotics field, e.g. the passenger vehicles with smart embedded systems. Such systems help drivers through sensors that acquire information from the surrounding environment and algorithms which process this data and make decisions to perform a task, like parking a car. This work aims to present the studies performed on the development of a smart controller able to park a simulated vehicle in parallel parking spaces, where a single maneuver is enough to enter. To accomplish this, studies involving the modeling of environments, vehicle kinematics and sensors were conducted, which were implemented in a simulated environment developed in C# with Visual Studio 2008. Next, a study about the three stages of parking was carried out, which consists in looking for a slot, positioning the vehicle and maneuvering it. The \"S\" trajectory was adopted and developed to maneuver the vehicle, since it is well known and highly used in related works found in the literature of this field. The maneuver consists in the correct positioning of two circumferences with the possible steering radius of the vehicle. For this task, a robust controller based on supervised learning using Artificial Neural Networks (ANN) was employed, since this approach has great robustness regarding the presence of noise in the system. This controller receives data from two laser sensors (one attached on the front of the vehicle and the other on the rear), from the odometry and from the inertial orientation sensor. The data acquired from these sensors and the current maneuver stage of the vehicle are the inputs of the controller, which interprets these data and responds to these stimuli in a correct way in approximately 99% of the cases. The results of the training and simulation were satisfactory, allowing the car controlled by the ANN to correctly park in a parallel slot.

Graças aos avanços tecnológicos nas áreas da computação, eletrônica embarcada e mecatrônica a robótica está cada vez mais presente no cotidiano da pessoas. Nessas últimas décadas, uma infinidade de ferramentas e métodos foram desenvolvidos no campo da Robótica Móvel. Um exemplo disso são os sistemas inteligentes embarcados nos veículos de passeio. Tais sistemas auxiliam na condução através de sensores que recebem informações do ambiente e algoritmos que analisam os dados e tomam decisões para realizar uma determinada tarefa, como por exemplo estacionar um carro. Este trabalho tem por objetivo apresentar estudos realizados no desenvolvimento de um controlador inteligente capaz de estacionar um veículo simulado em vagas paralelas, na qual seja possível entrar com uma única manobra. Para isso, foi necessário realizar estudos envolvendo a modelagem de ambientes, cinemática veicular e sensores, os quais foram implementados em um ambiente de simulação desenvolvido em C# com o Visual Studio 2008. Em seguida é realizado um estudo sobre as três etapas do estacionamento, que consistem em procurar uma vaga, posicionar o veículo e manobrá-lo. Para realizar a manobra foi adotada a trajetória em S desenvolvida e muito utilizada em outros trabalhos encontrados na literatura da área. A manobra consiste em posicionar corretamente duas circunferências com um raio de esterçamento do veículo. Sendo assim, foi utilizado um controlador robusto baseado em aprendizado supervisionado utilizando Redes Neurais Artificiais (RNA), pois esta abordagem apresenta grande robustez com relação à presença de ruídos no sistema. Este controlador recebe dados de dois sensores laser (um fixado na frente do veículo e o outro na parte traseira), da odometria e de orientação de um sensor inercial. Os dados adquiridos desses sensores e a etapa da manobra em que o veículo está, servem de entrada para o controlador. Este é capaz de interpretar tais dados e responder a esses estímulos de forma correta em aproximadamente 99% dos casos. Os resultados de treinamento e de simulação se mostraram muito satisfatórios, permitindo que o carro controlador pela RNA pudesse estacionar corretamente em uma vaga paralela. / Thanks to technological advances in the fields of computer science, embedded electronics and mechatronics, robotics is increasingly more present in people\'s lives. On the past few decades a great variety of tools and methods were developed in the Mobile Robotics field, e.g. the passenger vehicles with smart embedded systems. Such systems help drivers through sensors that acquire information from the surrounding environment and algorithms which process this data and make decisions to perform a task, like parking a car. This work aims to present the studies performed on the development of a smart controller able to park a simulated vehicle in parallel parking spaces, where a single maneuver is enough to enter. To accomplish this, studies involving the modeling of environments, vehicle kinematics and sensors were conducted, which were implemented in a simulated environment developed in C# with Visual Studio 2008. Next, a study about the three stages of parking was carried out, which consists in looking for a slot, positioning the vehicle and maneuvering it. The \"S\" trajectory was adopted and developed to maneuver the vehicle, since it is well known and highly used in related works found in the literature of this field. The maneuver consists in the correct positioning of two circumferences with the possible steering radius of the vehicle. For this task, a robust controller based on supervised learning using Artificial Neural Networks (ANN) was employed, since this approach has great robustness regarding the presence of noise in the system. This controller receives data from two laser sensors (one attached on the front of the vehicle and the other on the rear), from the odometry and from the inertial orientation sensor. The data acquired from these sensors and the current maneuver stage of the vehicle are the inputs of the controller, which interprets these data and responds to these stimuli in a correct way in approximately 99% of the cases. The results of the training and simulation were satisfactory, allowing the car controlled by the ANN to correctly park in a parallel slot.

A segmentaçãoo de imagens é fundamental para a visão computacional. Com essa finalidade, a textura tem sido uma propriedade bastante explorada por pesquisadores. Porém, a existência de diversos métodos de extração de textura, muitas vezes específicos para determinadas aplicações, dificulta a implementação de sistemas de escopo mais geral. Tendo esse contexto como motivação e inspirado no sucesso dos sistemas de visão naturais e em sua generalidade, este trabalho propõe a combinação de métodos por meio da seleção de características baseada na saliência das sinapses de um perceptron multicamadas (MLP). É proposto, também, um método alternativo baseado na capacidade do MLP de apreender textura que dispensa o uso de técnicas de extração de textura. Como principal contribuição, além da comparação da heurística de seleção proposta frente à busca exaustiva segundo o critério da distância de Jeffrey-Matusita, foi introduzida a técnica de Equalização da Entrada, que melhorou consideravelmente a qualidade da medida de saliência. É também apresentada a segmentação de imagens de cenas naturais, como exemplo de aplicação / Segmentation is a crucial step in Computer Vision. Texture has been a property largely employed by many researchers to achieve segmentation. The existence of a large amount of texture extraction methods is, sometimes, a hurdle to overcome when it comes to modeling systems for more general problems. Inside this context and following the excellence of natural vision systems and their generality, this work has adopted a feature selection method based on synaptic conexions salience of a Multilayer Perceptron and a method based on its texture inference capability. As well as comparing the proposed method with exhaustive search according to the Jeffrey-Matusita distance criterion, this work also introduces, as a major contribution, the Input Equalization technique, which contributed to significantly improve the segmentation results. The segmentation of images of natural scenes has also been provided as a likely application of the method

<p>Die trainingswissenschaftliche Diagnostik in den Kernbereichen Training, Wettkampf und Leistungsfähigkeit ist durch einen hohen Praxisbezug, eine ausgeprägte strukturelle Komplexität und vielseitige Wechselwirkungen der sportwissenschaftlichen Teilgebiete geprägt. Diese Eigenschaften haben in der Vergangenheit dazu geführt, dass zentrale Fragestellungen, wie beispielsweise die Maximierung der sportlichen Leistungsfähigkeit, eine ökonomische Trainingsgestaltung, eine effektive Talentauswahl und -sichtung oder die Modellbildung noch nicht vollständig gelöst werden konnten. Neben den bereits vorhandenen linearen Lösungsansätzen werden in dieser Arbeit Methoden aus dem Bereich der Neuronalen Netzwerke eingesetzt. Diese nichtlinearen Diagnoseverfahren sind besonders geeignet für die Analyse von Prozessabläufen, wie sie beispielsweise im Training vorliegen.</p> <p>Im theoretischen Teil werden zunächst Gemeinsamkeiten, Abhängigkeiten und Unterschiede in den Bereichen Training, Wettkampf und Leistungsfähigkeit untersucht sowie die Brücke zwischen trainingswissenschaftlicher Diagnostik und nichtlinearen Verfahren über die Begriffe der Interdisziplinarität und Integrativität geschlagen. Angelehnt an die Theorie der Neuronalen Netze werden anschließend die Grundlagenmodelle Perzeptron, Multilayer-Perzeptron und Selbstorganisierende Karten theoretisch erläutert. Im empirischen Teil stehen dann die nichtlineare Analyse von personalen Anforderungsstrukturen, Zustände der sportlichen Form und die Prognose sportlichen Talents - allesamt bei jugendlichen Leistungsschwimmerinnen und -schwimmern - im Mittelpunkt. Die nichtlinearen Methoden werden dabei einerseits auf ihre wissenschaftliche Aussagekraft überprüft, andererseits untereinander sowie mit linearen Verfahren verglichen.</p> / <p>The diagnostic methods in training science concentrate on the core areas of training, competition, and performance. The methods commonly used are characterized by a high degree of practical applicability and distinct structural complexity. These characteristics have led to the question which scientific methods fit best for resolving problems like, for example, the optimization of athletic performance, efficient planning and monitoring of training processes, effective talent screening, selection and development, or the formation of analytical models. All these questions have not yet been answered sufficiently.</p> <p>Aside from the traditional mathematical approaches on the basis of the linear model, nonlinear methods in the field of neural networks are used in this dissertation. These nonlinear diagnostic methods are especially suitable for the analysis of coherent patterns in time series such as training processes.</p> <p>In the theoretical part of the dissertation, common aspects, mutual dependencies, and differences between training, competition, and performance are examined. In this context, a bridge is built between the diagnostic purposes in these fields and suitable nonlinear methods. Along the lines of the neural networks theory, the basic models Perceptron, Multilayer-Perceptron, and Self-Organizing Feature Maps are subsequently elucidated.</p> <p>In the empirical part of the thesis, three studies conducted with top level adolescent swimmers are presented that focus on the nonlinear analysis of personal athletic ability structures, different states of athletic shape, and the prognosis of athletic talent. The nonlinear methods are thus examined as to how worthwhile they are for analytical purposes in training science on the one hand, and they are compared to each other as well as to linear methods on the other hand.</p>

Safety and reliability are prime concerns in aircraft performance due to the involved costs and risk to lives. Despite the best efforts in design methodology, quality evaluation in production and structural integrity assessment in-service, attainment of one hundred percent safety through development and use of a suitable in-flight health monitoring system is still a farfetched goal. And, evolution of such a system requires, first, identification of an appropriate Technique and next its adoption to meet the challenges posed by newer materials (advanced composites), complex structures and the flight environment. In fact, a quick survey of the available Non-Destructive Evaluation (NDE) techniques suggests Acoustic Emission (AE) as the only available method. High merit in itself could be a weakness - Noise is the worst enemy of AE. So, while difficulties are posed due to the insufficient understanding of the basic behavior of composites, growth and interaction of defects and damage under a specified load condition, high in-flight noise further complicates the issue making the developmental task apparently formidable and challenging. Development of an in-flight monitoring system based on AE to function as an early warning system needs addressing three aspects, viz., the first, discrimination of AE signals from noise data, the second, extraction of required information from AE signals for identification of sources (source characterization) and quantification of its growth, and the third, automation of the entire process. And, a quick assessment of the aspects involved suggests that Artificial Neural Networks (ANN) are ideally suited for solving such a complex problem. A review of the available open literature while indicates a number of investigations carried out using noise elimination and source characterization methods such as frequency filtering and statistical pattern recognition but shows only sporadic attempts using ANN. This may probably be due to the complex nature of the problem involving investigation of a large number of influencing parameters, amount of effort and time to be invested, and facilities required and multi-disciplinary nature of the problem. Hence as stated in the foregoing, the need for such a study cannot be over emphasized. Thus, this thesis is an attempt addressing the issue of analysis and automation of complex sets of AE data such as AE signals mixed with in-flight noise thus forming the first step towards in-flight monitoring using AE. An ANN can in fact replace the traditional algorithmic approaches used in the past. ANN in general are model free estimators and derive their computational efficiency due to large connectivity, massive parallelism, non-linear analog response and learning capabilities. They are better suited than the conventional methods (statistical pattern recognition methods) due to their characteristics such as classification, pattern matching, learning, generalization, fault tolerance and distributed memory and their ability to process unstructured data sets which may be carrying incomplete information at times and hence chosen as the tool. Further, in the current context, the set of investigations undertaken were in the absence of sufficient a priori information and hence clustering of signals generated by AE sources through self-organizing maps is more appropriate. Thus, in the investigations carried out under the scope of this thesis, at first a hybrid network named "NAEDA" (Neural network for Acoustic Emission Data Analysis) using Kohonen self-organizing feature map (KSOM) and multi-layer perceptron (MLP) that learns on back propagation learning rule was specifically developed with innovative data processing techniques built into the network. However, for accurate pattern recognition, multi-layer back propagation NN needed to be trained with source and noise clusters as input data. Thus, in addition to optimizing the network architecture and training parameters, preprocessing of input data to the network and multi-class clustering and classification proved to be the corner stones in obtaining excellent identification accuracy. Next, in-flight noise environment of an aircraft was generated off line through carefully designed simulation experiments carried out in the laboratory (Ex: EMI, friction, fretting and other mechanical and hydraulic phenomena) based on the in-flight noise survey carried out by earlier investigators. From these experiments data was acquired and classified into their respective classes through MLP. Further, these noises were mixed together and clustered through KSOM and then classified into their respective clusters through MLP resulting in an accuracy of 95%- 100% Subsequently, to evaluate the utility of NAEDA for source classification and characterization, carbon fiber reinforced plastic (CFRP) specimens were subjected to spectrum loading simulating typical in-flight load and AE signals were acquired continuously up to a maximum of three designed lives and in some cases up to failure. Further, AE signals with similar characteristics were grouped into individual clusters through self-organizing map and labeled as belonging to appropriate failure modes, there by generating the class configuration. Then MLP was trained with this class information, which resulted in automatic identification and classification of failure modes with an accuracy of 95% - 100%. In addition, extraneous noise generated during the experiments was acquired and classified so as to evaluate the presence or absence of such data in the AE data acquired from the CFRP specimens. In the next stage, noise and signals were mixed together at random and were reclassified into their respective classes through supervised training of multi-layer back propagation NN. Initially only noise was discriminated from the AE signals from CFRP failure modes and subsequently both noise discrimination and failure mode identification and classification was carried out resulting in an accuracy of 95% - 100% in most of the cases. Further, extraneous signals mentioned above were classified which indicated the presence of such signals in the AE signals obtained from the CFRP specimen. Thus, having established the basis for noise identification and AE source classification and characterization, two specific examples were considered to evaluate the utility and efficiency of NAEDA. In the first, with the postulation that different basic failure modes in composites have unique AE signatures, the difference in damage generation and progression can be clearly characterized under different loading conditions. To examine this, static compression tests were conducted on a different set of CFRP specimens till failure with continuous AE monitoring and the resulting AE signals were classified through already trained NAEDA. The results obtained shows that the total number of signals obtained were very less when compared to fatigue tests and the specimens failed with hardly any damage growth. Further, NAEDA was able to discriminate the"noise and failure modes in CFRP specimen with the same degree of accuracy with which it has classified such signals obtained from fatigue tests. In the second example, with the same postulate of unique AE signatures for different failure modes, the differences in the complexion of the damage growth and progression should become clearly evident when one considers specimens with different lay up sequences. To examine this, the data was reclassified on the basis of differences in lay up sequences from specimens subjected to fatigue. The results obtained clearly confirmed the postulation. As can be seen from the summary of the work presented in the foregoing paragraphs, the investigations undertaken within the scope of this thesis involve elaborate experimentation, development of tools, acquisition of extensive data and analysis. Never the less, the results obtained were commensurate with the efforts and have been fruitful. Of the useful results that have been obtained, to state in specific, the first is, discrimination of simulated noise sources achieved with significant success but for some overlapping which is not of major concern as far as noises are concerned. Therefore they are grouped into required number of clusters so as to achieve better classification through supervised NN. This proved to be an innovative measure in supervised classification through back propagation NN. The second is the damage characterization in CFRP specimens, which involved imaginative data processing techniques that proved their worth in terms of optimization of various training parameters and resulted in accurate identification through clustering. Labeling of clusters is made possible by marking each signal starting from clustering to final classification through supervised neural network and is achieved through phenomenological correlation combined with ultrasonic imaging. Most rewarding of all is the identification of failure modes (AE signals) mixed in noise into their respective classes. This is a direct consequence of innovative data processing, multi-class clustering and flexibility of grouping various noise signals into suitable number of clusters. Thus, the results obtained and presented in this thesis on NN approach to AE signal analysis clearly establishes the fact that methods and procedures developed can automate detection and identification of failure modes in CFRP composites under hostile environment, which could lead to the development of an in-flight monitoring system.

The hybridization of soft computing methods of Radial Basis Function (RBF) neural networks, Multi Layer Perceptron (MLP) neural networks with back-propagation learning, fuzzy sets and rough sets are studied in the scope of this thesis. Conventional MLP, conventional RBF, fuzzy MLP, fuzzy RBF, rough fuzzy MLP, and rough fuzzy RBF networks are compared. In the fuzzy neural networks implemented in this thesis, the input data and the desired outputs are given fuzzy membership values as the fuzzy properties &ldquo / low&rdquo / , &ldquo / medium&rdquo / and &ldquo / high&rdquo / . In the rough fuzzy MLP, initial weights and near optimal number of hidden nodes are estimated using rough dependency rules. A rough fuzzy RBF structure similar to the rough fuzzy MLP is proposed. The rough fuzzy RBF was inspected whether dependencies like the ones in rough fuzzy MLP can be concluded.

The thesis reports a contribution to the development of neural-like network- based element-free methods for the numerical simulation of some non-Newtonian fluid flow problems. The numerical approximation of functions and solution of the governing partial differential equations are mainly based on radial basis function networks. The resultant micro-macroscopic approaches do not require any element-based discretisation and only rely on a set of unstructured collocation points and hence are truly meshless or element-free. The development of the present methods begins with the use of the multi-layer perceptron networks (MLPNs) and radial basis function networks (RBFNs) to effectively eliminate the volume integrals in the integral formulation of fluid flow problems. An adaptive velocity gradient domain decomposition (AVGDD) scheme is incorporated into the computational algorithm. As a result, an improved feed forward neural network boundary-element-only method (FFNN- BEM) is created and verified. The present FFNN-BEM successfully simulates the flow of several Generalised Newtonian Fluids (GNFs), including the Carreau, Power-law and Cross models. To the best of the author's knowledge, the present FFNN-BEM is the first to achieve convergence for difficult flow situations when the power-law indices are very small (as small as 0.2). Although some elements are still used to discretise the governing equations, but only on the boundary of the analysis domain, the experience gained in the development of element-free approximation in the domain provides valuable skills for the progress towards an element-free approach. A least squares collocation RBFN-based mesh-free method is then developed for solving the governing PDEs. This method is coupled with the stochastic simulation technique (SST), forming the mesoscopic approach for analyzing viscoelastic flid flows. The velocity field is computed from the RBFN-based mesh-free method (macroscopic component) and the stress is determined by the SST (microscopic component). Thus the SST removes a limitation in traditional macroscopic approaches since closed form constitutive equations are not necessary in the SST. In this mesh-free method, each of the unknowns in the conservation equations is represented by a linear combination of weighted radial basis functions and hence the unknowns are converted from physical variables (e.g. velocity, stresses, etc) into network weights through the application of the general linear least squares principle and point collocation procedure. Depending on the type of RBFs used, a number of parameters will influence the performance of the method. These parameters include the centres in the case of thin plate spline RBFNs (TPS-RBFNs), and the centres and the widths in the case of multi-quadric RBFNs (MQ-RBFNs). A further improvement of the approach is achieved when the Eulerian SST is formulated via Brownian configuration fields (BCF) in place of the Lagrangian SST. The SST is made more efficient with the inclusion of the control variate variance reduction scheme, which allows for a reduction of the number of dumbbells used to model the fluid. A highly parallelised algorithm, at both macro and micro levels, incorporating a domain decomposition technique, is implemented to handle larger problems. The approach is verified and used to simulate the flow of several model dilute polymeric fluids (the Hookean, FENE and FENE-P models) in simple as well as non-trivial geometries, including shear flows (transient Couette, Poiseuille flows)), elongational flows (4:1 and 10:1 abrupt contraction flows) and lid-driven cavity flows.

A segmentaçãoo de imagens é fundamental para a visão computacional. Com essa finalidade, a textura tem sido uma propriedade bastante explorada por pesquisadores. Porém, a existência de diversos métodos de extração de textura, muitas vezes específicos para determinadas aplicações, dificulta a implementação de sistemas de escopo mais geral. Tendo esse contexto como motivação e inspirado no sucesso dos sistemas de visão naturais e em sua generalidade, este trabalho propõe a combinação de métodos por meio da seleção de características baseada na saliência das sinapses de um perceptron multicamadas (MLP). É proposto, também, um método alternativo baseado na capacidade do MLP de apreender textura que dispensa o uso de técnicas de extração de textura. Como principal contribuição, além da comparação da heurística de seleção proposta frente à busca exaustiva segundo o critério da distância de Jeffrey-Matusita, foi introduzida a técnica de Equalização da Entrada, que melhorou consideravelmente a qualidade da medida de saliência. É também apresentada a segmentação de imagens de cenas naturais, como exemplo de aplicação / Segmentation is a crucial step in Computer Vision. Texture has been a property largely employed by many researchers to achieve segmentation. The existence of a large amount of texture extraction methods is, sometimes, a hurdle to overcome when it comes to modeling systems for more general problems. Inside this context and following the excellence of natural vision systems and their generality, this work has adopted a feature selection method based on synaptic conexions salience of a Multilayer Perceptron and a method based on its texture inference capability. As well as comparing the proposed method with exhaustive search according to the Jeffrey-Matusita distance criterion, this work also introduces, as a major contribution, the Input Equalization technique, which contributed to significantly improve the segmentation results. The segmentation of images of natural scenes has also been provided as a likely application of the method

This research investigates the use of an alternate means of modelling the performance of a train of feed water heaters in a steam cycle power plant, using machine learning. The goal of this study was to use a simple artificial neural network (ANN) to predict the behaviour of the plant system, specifically the inlet bled steam (BS) mass flow rate and the outlet water temperature of each feedwater heater. The output of the model was validated through the use of a thermofluid engineering model built for the same plant. Another goal was to assess the ability of both the thermofluid model and ANN model to predict plant behaviour under out of normal operating circumstances. The thermofluid engineering model was built on FLOWNEX® SE using existing custom components for the various heat exchangers. The model was then tuned to current plant conditions by catering for plant degradation and maintenance effects. The artificial neural network was of a multi-layer perceptron (MLP) type, using the rectified linear unit (ReLU) activation function, mean squared error (MSE) loss function and adaptive moments (Adam) optimiser. It was constructed using Python programming language. The ANN model was trained using the same data as the FLOWNEX® SE model. Multiple architectures were tested resulting in the optimum model having two layers, 200 nodes or neurons in each layer with a batch size of 500, running over 100 epochs. This configuration attained a training accuracy of 0.9975 and validation accuracy of 0.9975. When used on a test set and to predict plant performance, it achieved a MSE of 0.23 and 0.45 respectively. Under normal operating conditions (six cases tested) the ANN model performed better than the FLOWNEX® SE model when compared to actual plant behaviour. Under out of normal conditions (four cases tested), the FLOWNEX SE® model performed better than the ANN. It is evident that the ANN model was unable to capture the “physics” of a heat exchanger or the feed heating process as a result of its poor performance in the out of normal scenarios. Further tuning by way of alternate activation functions and regularisation techniques had little effect on the ANN model performance. The ANN model was able to accurately predict an out of normal case only when it was trained to do so. This was achieved by augmenting the original training data with the inputs and results from the FLOWNEX SE® model for the same case. The conclusion drawn from this study is that this type of simple ANN model is able to predict plant performance so long as it is trained for it. The validity of the prediction is highly dependent on the integrity of the training data. Operating outside the range which the model was trained for will result in inaccurate predictions. It is recommended that out of normal scenarios commonly experienced by the plant be synthesised by engineering modelling tools like FLOWNEX® SE to augment the historic plant data. This provides a wider spectrum of training data enabling more generalised and accurate predictions from the ANN model.