A calibration approach based on Takagi-Sugeno fuzzy inference system for digital electronic compasses

Recently, the development of industrial processes brought on the outbreak of technologically complex systems. This development generated the necessity of research relative to the mathematical techniques that have the capacity to deal with project complexities and validation. Fuzzy models have been receiving particular attention in the area of nonlinear systems identification and analysis due to it is capacity to approximate nonlinear behavior and deal with uncertainty. A fuzzy rule-based model suitable for the approximation of many systems and functions is the Takagi-Sugeno (TS) fuzzy model. IS fuzzy models are nonlinear systems described by a set of if then rules which gives local linear representations of an underlying system. Such models can approximate a wide class of nonlinear systems. In this paper a performance analysis of a system based on IS fuzzy inference system for the calibration of electronic compass devices is considered. The contribution of the evaluated IS fuzzy inference system is to reduce the error obtained in data acquisition from a digital electronic compass. For the reliable operation of the TS fuzzy inference system, adequate error measurements must be taken. The error noise must be filtered before the application of the IS fuzzy inference system. The proposed method demonstrated an effectiveness of 57% at reducing the total error based on considered tests. (C) 2011 Elsevier Ltd. All rights reserved.

A split-pot experiment with sorghum to test a root water uptake partitioning model

Correct modeling of root water uptake partitioning over depth is an important issue in hydrological and crop growth models. Recently a physically based model to describe root water uptake was developed at single root scale and upscaled to the root system scale considering a homogeneous distribution of roots per soil layer. Root water uptake partitioning is calculated over soil layers or compartments as a function of respective soil hydraulic conditions, specifically the soil matric flux potential, root characteristics and a root system efficiency factor to compensate for within-layer root system heterogeneities. The performance of this model was tested in an experiment performed in two-compartment split-pot lysimeters with sorghum plants. The compartments were submitted to different irrigation cycles resulting in contrasting water contents over time. The root system efficiency factor was determined to be about 0.05. Release of water from roots to soil was predicted and observed on several occasions during the experiment; however, model predictions suggested root water release to occur more often and at a higher rate than observed. This may be due to not considering internal root system resistances, thus overestimating the ease with which roots can act as conductors of water. Excluding these erroneous predictions from the dataset, statistical indices show model performance to be of good quality.

Molecular sieve silica membranes for H2/CO separation

Efficient separation of fuel gas (H2) from other gases in reformed gas mixtures is becoming increasingly important in the development of alternative energy systems. A highly efficient and new technology available for these separations is molecular sieve silica (MSS) membranes derived from tetraethyl-orthosilicate (TEOS). A permeation model is developed from an analogous electronic system and compared to transport theory to determine permeation, selectivity and apparent activation of energy based on experimental values. Experimental results for high quality membranes show single gas permselectivity peaking at 57 for H2/CO at 150°C with a H2 permeation of 5.14 x 10^-8 mol.m^-2.s^-1.Pa^-1. Higher permeance was also achieved, but at the expense of selectivity. This is the case for low quality membranes with peak H2 permeation at 1.78 x 10-7 mol.m-2.s-1.Pa-1 at 22°C and H2/CO permselectivity of 4.5. High quality membranes are characterised with positive apparent activation energy while the low quality membranes have negative values. The model had a good fit of r-squared of 0.99-1.00 using the experimental data.

Loss of Ergodicity in the Transition from Annealed to Quenched Disorder in a Finite Kinetic Ising Model

We consider a kinetic Ising model which represents a generic agent-based model for various types of socio-economic systems. We study the case of a finite (and not necessarily large) number of agents N as well as the asymptotic case when the number of agents tends to infinity. The main ingredient are individual decision thresholds which are either fixed over time (corresponding to quenched disorder in the Ising model, leading to nonlinear deterministic dynamics which are generically non-ergodic) or which may change randomly over time (corresponding to annealed disorder, leading to ergodic dynamics). We address the question how increasing the strength of annealed disorder relative to quenched disorder drives the system from non-ergodic behavior to ergodicity. Mathematically rigorous analysis provides an explicit and detailed picture for arbitrary realizations of the quenched initial thresholds, revealing an intriguing ""jumpy"" transition from non-ergodicity with many absorbing sets to ergodicity. For large N we find a critical strength of annealed randomness, above which the system becomes asymptotically ergodic. Our theoretical results suggests how to drive a system from an undesired socio-economic equilibrium (e. g. high level of corruption) to a desirable one (low level of corruption).

The plausibility of long-wavelength stress correlation or stress magnitude as a mechanism for precursory seismicity: Results from two simple elastic models

Observations of accelerating seismic activity prior to large earthquakes in natural fault systems have raised hopes for intermediate-term eartquake forecasting. If this phenomena does exist, then what causes it to occur? Recent theoretical work suggests that the accelerating seismic release sequence is a symptom of increasing long-wavelength stress correlation in the fault region. A more traditional explanation, based on Reid's elastic rebound theory, argues that an accelerating sequence of seismic energy release could be a consequence of increasing stress in a fault system whose stress moment release is dominated by large events. Both of these theories are examined using two discrete models of seismicity: a Burridge-Knopoff block-slider model and an elastic continuum based model. Both models display an accelerating release of seismic energy prior to large simulated earthquakes. In both models there is a correlation between the rate of seismic energy release with the total root-mean-squared stress and the level of long-wavelength stress correlation. Furthermore, both models exhibit a systematic increase in the number of large events at high stress and high long-wavelength stress correlation levels. These results suggest that either explanation is plausible for the accelerating moment release in the models examined. A statistical model based on the Burridge-Knopoff block-slider is constructed which indicates that stress alone is sufficient to produce accelerating release of seismic energy with time prior to a large earthquake.

Simulação de um Pool Simétrico com validação técnica do despacho provisório e apresentação de medidas corretivas baseadas num despacho ótimo

Os mercados de energia elétrica são atualmente uma realidade um pouco por todo o mundo. Contudo, não é consensual o modelo regulatório a utilizar, o que origina a utilização de diferentes modelos nos diversos países que deram início ao processo de liberalização e de reestruturação do sector elétrico. A esses países, dado que a energia elétrica não é um bem armazenável, pelo menos em grandes quantidades, colocam-se questões importantes relacionadas com a gestão propriamente dita do seu sistema elétrico. Essas questões implicam a adoção de regras impostas pelo regulador que permitam ultrapassar essas questões. Este trabalho apresenta um estudo feito aos mercados de energia elétrica existentes um pouco por todo o mundo e que o autor considerou serem os mais importantes. Foi também feito um estudo de ferramentas de otimização essencialmente baseado em meta-heurísticas aplicadas a problemas relacionados com a operação dos mercados e com os sistemas elétricos de energia, como é o exemplo da resolução do problema do Despacho Económico. Foi desenvolvida uma aplicação que simula o funcionamento de um mercado que atua com o modelo Pool Simétrico, em que são transmitidas as ofertas de venda e compra de energia elétrica por parte dos produtores, por um lado, e dos comercializadores, consumidores elegíveis ou intermediários financeiros, por outro, analisando a viabilidade técnica do Despacho Provisório. A análise da viabilidade técnica do Despacho Provisório é verificada através do modelo DC de trânsito de potências. No caso da inviabilidade do Despacho Provisório, por violação de restrições afetas ao problema, são determinadas medidas corretivas a esse despacho, com base nas ofertas realizadas e recorrendo a um Despacho Ótimo. Para a determinação do Despacho Ótimo recorreu-se à meta-heurística Algoritmos Genéticos. A aplicação foi desenvolvida no software MATLAB utilizando a ferramenta Graphical User Interfaces. A rede de teste utilizada foi a rede de 14 barramentos do Institute of Electrical and Electronics Engineers (IEEE). A aplicação mostra-se competente no que concerne à simulação de um mercado com tipo de funcionamento Pool Simétrico onde são efetuadas ofertas simples e onde as transações ocorrem no mercado diário, porém, não reflete o problema real relacionado a este tipo de mercados. Trata-se, portanto, de um simulador básico de um mercado de energia cujo modelo de funcionamento se baseia no tipo Pool Simétrico.

Numerical 3D modeling of heat transfer in human tissues for microwave radiometry monitoring of Brown fat metabolismo

Background: Brown adipose tissue (BAT) plays an important role in whole body metabolism and could potentially mediate weight gain and insulin sensitivity. Although some imaging techniques allow BAT detection, there are currently no viable methods for continuous acquisition of BAT energy expenditure. We present a non-invasive technique for long term monitoring of BAT metabolism using microwave radiometry. Methods: A multilayer 3D computational model was created in HFSS™ with 1.5 mm skin, 3-10 mm subcutaneous fat, 200 mm muscle and a BAT region (2-6 cm3) located between fat and muscle. Based on this model, a log-spiral antenna was designed and optimized to maximize reception of thermal emissions from the target (BAT). The power absorption patterns calculated in HFSS™ were combined with simulated thermal distributions computed in COMSOL® to predict radiometric signal measured from an ultra-low-noise microwave radiometer. The power received by the antenna was characterized as a function of different levels of BAT metabolism under cold and noradrenergic stimulation. Results: The optimized frequency band was 1.5-2.2 GHz, with averaged antenna efficiency of 19%. The simulated power received by the radiometric antenna increased 2-9 mdBm (noradrenergic stimulus) and 4-15 mdBm (cold stimulus) corresponding to increased 15-fold BAT metabolism. Conclusions: Results demonstrated the ability to detect thermal radiation from small volumes (2-6 cm3) of BAT located up to 12 mm deep and to monitor small changes (0.5°C) in BAT metabolism. As such, the developed miniature radiometric antenna sensor appears suitable for non-invasive long term monitoring of BAT metabolism.

Customisable e-training programmes based on trainees profiles

Dissertation presented at Faculdade de Ciências e Tecnologia of Universidade Nova de Lisboa to obtain the Master degree in Electrical and Computer Engineering

Rede de Calor – Uma Solução a Biomassa para um Complexo de Hóteis

O recurso às energias renováveis é na actualidade um tema que atinge um grau de importância primordial face á crescente preocupação com o meio ambiente e o impacto negativo, que a produção de energia com base em combustíveis fósseis tem. Esta importância aliada a uma tendência cada vez maior para a criação de soluções de produção sustentável de energia, tem obrigado ao desenvolvimento desta vertente do sector energético e ao estudo e consequentemente implementação de soluções integradas que permitam uma economia competitiva. Os hotéis, sendo estabelecimentos comerciais que desenvolvem uma actividade que envolve, na generalidade, um nível de consumo energético considerável para garantir os seus serviços básicos de acomodação e lazer, tornam-se por excelência alvos primordiais no que concerne ao seu elevado potencial de poupança de energia. O ramo da hotelaria, dada a sua especificidade e a natureza dos edifícios que comporta, torna-os em excelentes candidatos para análise e optimização energética, e como tal um alvo de negócio para as empresas de comercialização de poupanças energéticas. As empresas dedicadas aos serviços de energia são conhecidas por ESCO (Energy Service Company ou Energy Savings Company). A sua actividade tem por base apresentar soluções de energia, nomeadamente a implementação de projectos de poupança energética que podem englobar produção, conservação e fornecimento de energia, bem como gestão de risco associada. O objectivo principal é apresentar soluções de optimização e eficiência energética levando á sua implementação em casos reais de exploração em edifícios ou sectores específicos, rentabilizando o investimento e partilhando o lucro dessa rentabilização com os clientes. No caso específico dos hotéis, mais concretamente um complexo de hotéis, como o estudado neste trabalho, esta análise pretende elaborar uma caracterização das necessidades energéticas do sector e apresentar um conjunto de soluções energéticas adequadas à realidade hoteleira. É também objecto de análise, toda a aproximação de um modelo de negócio energético a explorar por uma ESCO. O presente trabalho, realizado no âmbito da parceria entre a Gebio e a Confraria do Bom Jesus, tem por objectivo demonstrar as bases do contracto de performance entre uma empresa ESCO (Gebio – empresa concessionária do projecto) e um complexo de hotéis (constituído pelo Hotel do Lago, Hotel do Parque e Hotel do Templo), com vista a optimizar os consumos energéticos para a produção de energia térmica capaz de corresponder às necessidades do complexo. Foi desenvolvido um estudo completo das necessidades térmicas do complexo, com vista a projectar uma solução integrada de produção de energia térmica, com recurso a uma caldeira de biomassa, para os hotéis. Foi realizado um levantamento extensivo dos consumos e custos energético do complexo, nomeadamente para as águas quentes sanitárias. Desta análise obtiveram-se os custos reais do sistema e com os mesmos foi possível, numa primeira fase, elaborar os diversos projectos, hidráulico, eléctricos e civil, de forma a se definir a solução base e quais os orçamentos previstos para a instalação de um sistema de produção a biomassa, e numa segunda fase foi estudada a viabilidade da assinatura de um contracto de performance entre a ESCO e o complexo de hotéis.

InnovationCity Ruhr: a prime example for social and technological innovation

The project “InnovationCity Ruhr” deals with the reconstruction of the city of Bottrop with regard to energy saving measures. The aim is to make the city more environmental friendly in order to create a model for other industrial cities. Until the conclusion of the project in the year 2020, it is planned to change the surface of Bottrop in several positive ways. This paper focuses on the description of the project to give the reader an example of what exactly is done within the scope of InnovationCity Ruhr. Besides that, the link to the subject of sociology shall be given in order to show that the project is a prime example for social innovation.

A framework for efficient model transformations

The reported productivity gains while using models and model transformations to develop entire systems, after almost a decade of experience applying model-driven approaches for system development, are already undeniable benefits of this approach. However, the slowness of higher-level, rule based model transformation languages hinders the applicability of this approach to industrial scales. Lower-level, and efficient, languages can be used but productivity and easy maintenance seize to exist. The abstraction penalty problem is not new, it also exists for high-level, object oriented languages but everyone is using them now. Why is not everyone using rule based model transformation languages then? In this thesis, we propose a framework, comprised of a language and its respective environment, designed to tackle the most performance critical operation of high-level model transformation languages: the pattern matching. This framework shows that it is possible to mitigate the performance penalty while still using high-level model transformation languages.

Analysis of a controversial decision process: the case of the pumped hydro storage power plant Atdorf in Germany

Based on the report for the unit “Métodos Interactivos de Participação e Decisão A” (Interactive methods of participation and decision A), coordinated by Prof. Lia Maldonado Teles de Vasconcelos and Prof. Nuno Miguel Ribeiro Videira Costa. This unit was provided for the PhD Program in Technology Assessment in 2015/2016.

Cell-based computational modeling of vascular morphogenesis using Tissue Simulation Toolkit.

Computational modeling has become a widely used tool for unraveling the mechanisms of higher level cooperative cell behavior during vascular morphogenesis. However, experimenting with published simulation models or adding new assumptions to those models can be daunting for novice and even for experienced computational scientists. Here, we present a step-by-step, practical tutorial for building cell-based simulations of vascular morphogenesis using the Tissue Simulation Toolkit (TST). The TST is a freely available, open-source C++ library for developing simulations with the two-dimensional cellular Potts model, a stochastic, agent-based framework to simulate collective cell behavior. We will show the basic use of the TST to simulate and experiment with published simulations of vascular network formation. Then, we will present step-by-step instructions and explanations for building a recent simulation model of tumor angiogenesis. Demonstrated mechanisms include cell-cell adhesion, chemotaxis, cell elongation, haptotaxis, and haptokinesis.

Agent based simulation to optimise emergency departments

Nowadays, many of the health care systems are large and complex environments and quite dynamic, specifically Emergency Departments, EDs. It is opened and working 24 hours per day throughout the year with limited resources, whereas it is overcrowded. Thus, is mandatory to simulate EDs to improve qualitatively and quantitatively their performance. This improvement can be achieved modelling and simulating EDs using Agent-Based Model, ABM and optimising many different staff scenarios. This work optimises the staff configuration of an ED. In order to do optimisation, objective functions to minimise or maximise have to be set. One of those objective functions is to find the best or optimum staff configuration that minimise patient waiting time. The staff configuration comprises: doctors, triage nurses, and admissions, the amount and sort of them. Staff configuration is a combinatorial problem, that can take a lot of time to be solved. HPC is used to run the experiments, and encouraging results were obtained. However, even with the basic ED used in this work the search space is very large, thus, when the problem size increases, it is going to need more resources of processing in order to obtain results in an acceptable time.

Hierarchical conditional random fields for parts based models matching

A parts based model is a parametrization of an object class using a collection of landmarks following the object structure. The matching of parts based models is one of the problems where pairwise Conditional Random Fields have been successfully applied. The main reason of their effectiveness is tractable inference and learning due to the simplicity of involved graphs, usually trees. However, these models do not consider possible patterns of statistics among sets of landmarks, and thus they sufffer from using too myopic information. To overcome this limitation, we propoese a novel structure based on a hierarchical Conditional Random Fields, which we explain in the first part of this memory. We build a hierarchy of combinations of landmarks, where matching is performed taking into account the whole hierarchy. To preserve tractable inference we effectively sample the label set. We test our method on facial feature selection and human pose estimation on two challenging datasets: Buffy and MultiPIE. In the second part of this memory, we present a novel approach to multiple kernel combination that relies on stacked classification. This method can be used to evaluate the landmarks of the parts-based model approach. Our method is based on combining responses of a set of independent classifiers for each individual kernel. Unlike earlier approaches that linearly combine kernel responses, our approach uses them as inputs to another set of classifiers. We will show that we outperform state-of-the-art methods on most of the standard benchmark datasets.