Designing robust forecasting ensembles of Data-Driven Models with a Multi-Objective Formulation: An application to Home Energy Management Systems

This work proposes a procedure for the multi-objective design of a robust forecasting ensemble of data-driven models. Starting with a data-selection algorithm, a multi-objective genetic algorithm is then executed, performing topology and feature selection, as well as parameter estimation. From the set of non-dominated or preferential models, a smaller sub-set is chosen to form the ensemble. Prediction intervals for the ensemble are obtained using the covariance method. This procedure is illustrated in the design of four different models, required for energy management systems. Excellent results were obtained by this methodology, superseding the existing alternatives. Further research will incorporate a robustness criterion in MOGA, and will incorporate the prediction intervals in predictive control techniques.Grant number 72581/2020info:eu-repo/semantics/publishedVersio

NILM techniques for intelligent home energy management and ambient assisted living: a review

The ongoing deployment of smart meters and different commercial devices has made electricity disaggregation feasible in buildings and households, based on a single measure of the current and, sometimes, of the voltage. Energy disaggregation is intended to separate the total power consumption into specific appliance loads, which can be achieved by applying Non-Intrusive Load Monitoring (NILM) techniques with a minimum invasion of privacy. NILM techniques are becoming more and more widespread in recent years, as a consequence of the interest companies and consumers have in efficient energy consumption and management. This work presents a detailed review of NILM methods, focusing particularly on recent proposals and their applications, particularly in the areas of Home Energy Management Systems (HEMS) and Ambient Assisted Living (AAL), where the ability to determine the on/off status of certain devices can provide key information for making further decisions. As well as complementing previous reviews on the NILM field and providing a discussion of the applications of NILM in HEMS and AAL, this paper provides guidelines for future research in these topics.Agência financiadora: Programa Operacional Portugal 2020 and Programa Operacional Regional do Algarve 01/SAICT/2018/39578 Fundação para a Ciência e Tecnologia through IDMEC, under LAETA: SFRH/BSAB/142998/2018 SFRH/BSAB/142997/2018 UID/EMS/50022/2019 Junta de Comunidades de Castilla-La-Mancha, Spain: SBPLY/17/180501/000392 Spanish Ministry of Economy, Industry and Competitiveness (SOC-PLC project): TEC2015-64835-C3-2-R MINECO/FEDERinfo:eu-repo/semantics/publishedVersio

Intelligent predictive control for thermal comfort and energy savings in public buildings

This talk addresses the problem of controlling a heating ventilating and air conditioning system with the purpose of achieving a desired thermal comfort level and energy savings. The formulation uses the thermal comfort, assessed using the predicted mean vote (PMV) index, as a restriction and minimises the energy spent to comply with it. This results in the maintenance of thermal comfort and on the minimisation of energy, which in most operating conditions are conflicting goals requiring some sort of optimisation method to find appropriate solutions over time

Forecasting electricity demand in households using MOGA-designed artificial neural networks

The prediction of electricity demand plays an essential role in the building environment. It strongly contributes to making the building more energy-efficient, having the potential to increase both thermal and visual comfort of the occupants, while reducing energy consumption, by allowing the use of model predictive control. The present article focuses on the use of computational intelligence methods for prediction of the power consumption of a case study residential building, during a horizon of 12 hours. Two exogeneous variables (ambient temperature and day code) are used in the NARX model Two different time steps were considered in the simulations, as well as constrained and unconstrained model design. The study concluded that the smaller timestep and the constrained model design obtain the best power demand prediction performance. The results obtained compare very favourably with similar approaches in the literature Copyright (C) 2020 The Authors.UIDB/50022/2020, 01/SAICT/2018info:eu-repo/semantics/publishedVersio

Smart home energy management

The new challenges on Information and Communication Technologies (ICT) in Automatic Home Systems (AHS) focus on the methods useful to monitor, control, and optimize the data management flow and the use of energy. An AHS is a residential dwelling, in some cases with a garden or an outdoor space, equipped with sensors and actuators to collect data and send controls according to the activities and expectations of the occupants/users. Home automation provides a centralized or distributed control of electrical appliances. Adding intelligence to the home environment, it would be possible to obtain, not only excellent levels of comfort, but also energy savings both inside and outside the dwelling, for instance using smart solutions for the management of the external lights and of the garden

The Development of Legislation on the Social Economy in Continental Western Europe

One of the main instruments for local development is the regulatory legal framework of the so-called Social Economy, a term and concept that is yet to be fully defined. The society’s approach to the generation of wealth encompasses different concepts, movements, approaches, and ways of acting, all of which pose a challenge to the determination of a precise definition. Within the European Union (E.U.), a common legislative base has been developed, although the specific legislation developed by each Member State has been uneven. The legislation may have started from the same common principles, but each country has adopted different legal forms. This work aims to outline the diverse ways of legislating on a concept that is still under construction and within similar legal frameworks, illustrating the lack of harmony between European states that, despite the sharing of borders and having common legislative foundations, distance themselves in the final legislation, a situation that does not benefit the economic unity of entrepreneurs with social principles

An intelligent support system for automatic detection of cerebral vascular accidents from brain CT images

Objective: This paper presents a Radial Basis Functions Neural Network (RBFNN) based detection system, for automatic identification of Cerebral Vascular Accidents (CVA) through analysis of Computed Tomographic (CT) images. Methods: For the design of a neural network classifier, a Multi Objective Genetic Algorithm (MOGA) framework is used to determine the architecture of the classifier, its corresponding parameters and input features by maximizing the classification precision, while ensuring generalization. This approach considers a large number of input features, comprising first and second order pixel intensity statistics, as well as symmetry/asymmetry information with respect to the ideal mid-sagittal line. Results: Values of specificity of 98% and sensitivity of 98% were obtained, at pixel level, by an ensemble of non-dominated models generated by MOGA, in a set of 150 CT slices (1,867,602 pixels), marked by a NeuroRadiologist. This approach also compares favorably at a lesion level with three other published solutions, in terms of specificity (86% compared with 84%), degree of coincidence of marked lesions (89% compared with 77%) and classification accuracy rate (96% compared with 88%). (C) 2017 Published by Elsevier Ireland Ltd.FCTIDMECLAETA [UID/EMS/50022/2013

Análisis de metodologías para la evaluación de la madera juvenil en la calidad de la madera

On conifer species, when growing, on the inner part of the log closer to the pith they produce wood with different characteristics, which show rapid and progressive changes in the rings outward from the pith in a transverse direction until a point is reached where the properties are stabilized. The area closer to the pith is called juvenile wood (JW) to distinguish it from the mature wood (MW). The JW is characterized by having a celular structure with smaller tracheid length, lumen diameter, wall thickness, transverse shrinkage, stiffness and cellulose/lignin ratio. Other properties are lower, such as density and mechanical properties but others, such as spiral grain and microfibril angle (MFA) are higher. One phenomenon sometimes related to JW is the presence of wider growthrings and high levels of compression wood, although these last two relationships are not mutually exclusive. The transition year (TY) between JW and MW can be found by analyzing all these different properties. The boundary tends to change according to the wood property studied with variable patterns from pith to bark. All of these characteristics have undesirable effects on the physical-mechanical and technological properties of the material for solid dimension lumber. Also, the higher the proportion of JW, the greater incidence of different drying distortions such as spring, bow, crook and twist resulting in diminished prospects for profitable end use and economic return for solid wood products. Different explanations to the presence of these variations have been proposed and different names have been given to these two areas that can be differentiated in transversal direction of the tree at any height. When considering the longitudinal variation, the nomenclature usually employed is corewood (CW) and outerwood (OW). But in this Thesis, we will use the JW/MW nomenclature as the Spanish industrial sector still uses it. There are several studies assessing the importance of juvenile wood for solid dimension lumber in Spain. But not much studies have been carried out on Mediterranean conifers regarding the effect of the silviculture on the amount of JW present on the bole. Basic specific gravity, MFA and densitometry have been extensively used as indicators of JW presence. In this Thesis different methodologies are studied for JW determination on Pinus nigra and Pinus sylvestris with different silvicultural management and those results are compared with the ones obtained from densitometry. The influence of silviculture on the TY in black pine and Scots pine stands in Spain using densitometry, is studied. This analysis is done using a segmented linear mixed model including the analysis of the different covariate effects, included in the models, on density. Also, the variations on the JW volume and tree taper produced depending on the silvicultural practices using latewood (LW) density radial variation, is considered. Other objective was to see if at basal height it is possible to estimate a TY, by means of the accumulated yearly height growth that can be related to the one obtained for yearly LW and medium density on Scots pine and black pine. It is assessed the feasibility of using multipoint near infrared spectra (NIRs) to differentiate between JW and MW. On the same way, the potential of the near infrared hyperspectral imaging (NIR-HI) for semi-automatic identification of JW and MW moieties carried out in Scots pine is also assessed. Finally, it is done a study of radial and angular shrinkage patterns in the transversal direction along different heights of the bole. Based on the results on shrinkages, the JW/MW areas obtained, are related to the ones obtained through densitometry. When assessing the JW area on a log, micro X-ray densitometry is a suitable method for its study, results showed that the best density trait for automatization of the process is LW density. If assessing the TY by increment cores, which can be done on standing trees, the pith needs to be in the extracted core in order to assess the boundary correctly. The function developed for segmented mixed models, provides a powerful and more stable tool to predict the TY in a large number of samples using LW density profiles. Drought index is relevant for the modelling affecting LW density, on the slope on the MW or the density in TY determination. Up to a height of 9 meters TY was reached prior to the implementation of any silvicultural treatment, so further sampling is necessary to assess whether any treatment could influence or shift the transition year outside the part influenced by the crown. However, within the crown and in the case of PN, pruning was found to affect the TY because the LW density required to reach it increased, thus delaying the TY and increasing LW density. In both pine species, thinning seems to have a significant albeit slight negative effect on LW density, while the thinning and pruning combined seemed to have a small positive effect on it, compared to the control group. These results presented here may vary depending on the intensity and the timing of thinning, as well as on the amount of green pruning carried out. The growth response after silvicultural treatments show that the amount of JW is reduced in percentage as total volume increases with any silvicultural treatment applied, for both species, in Mediterranean forests. The TY calculated using Chapman-Richards growth functions on the accumulated height increments, does not fit the estimation of the TY obtained through density for the Spanish provenances studied of Scots and black pines. The calibration between measurements obtained with multipoint NIRs and density data derived from micro X-ray densitometry has been found difficult to obtain good enough results. On the other side NIR-HI can be calibrated with μXRD results and the JW, MW and transition point (TP) between both, can be determined on the transversal section of the tree. The results are independent from the silvicultural treatment applied in the Scots pine plantations studied. The principal component analysis was a useful and easy way to provide additional information on the presence and location of compression wood. The partial least squares discriminant analysis approach was the best procedure for detecting the TP between JW and MW, when the EW and LW were evaluated separately. Every strip was classified within ±1 annual ring difference compared with the LW. The biggest margin was ±2 annual rings. A previous automatic classification, by combination with a partitional k-means unsupervised classification, between EW and LW, would probably improve the results and could lead to a better automation of the process. Radial shrinkage tends to be in the first rings, up to the first 8 rings near the pith, between 4 and 9 %, decreasing until it stabilizes around 3%. Regarding the angular shrinkage, is close to 0% or even negative near the pith and increases until a certain ring (9-11) when it becomes more or less stable at around 2 %. These results are valid all along the bole, being greater and the transition produced earlier in radial shrinkage than in the angular one in each height studied. No general patterns can be seen along the same tree at the different heights sampled. Applying silvicultural treatments seems not to have any significance on the radial and angular shrinkage variation. If density is not an issue for the strength grading of solid dimension timber, the volume regarding the area where the shrinkage is stable suggest that, if the longitudinal shrinkage follows a similar pattern, the area that could be segregated for higher quality is bigger than the one provided by latewood density radial variation.En las distintas especies de coníferas, en la parte interna del tronco más cercana a la médula se genera, al crecer, madera que presenta cambios rápidos y progresivos en los sucesivos anillos hacia la corteza en dirección transversal, hasta que se alcanza un punto donde las propiedades se estabilizan para el resto de los anillos. El área más cercana a la medula se llama madera juvenil (JW) para distinguirla de la madera madura (MW). La JW se caracteriza por tener una estructura celular con menor longitud de traqueidas, diámetros de lúmenes, espesor de pared, contracción transversal, rigidez y relación celulosa/lignina. Unas propiedades que también son más bajas serían la densidad y las propiedades mecánicas, pero otras, como el grano en espiral y el ángulo de microfibrillas (MFA), son mayores. Un fenómeno a veces relacionado con la JW es la presencia de anillos de crecimiento más amplios y altos niveles de madera de compresión, aunque estas dos últimas relaciones no son mutuamente excluyentes. El año de transición (TY) entre JW y MW se puede encontrar mediante el análisis de todas estas diferentes propiedades que caracterizan a la JW. El límite tiende a cambiar según la propiedad de madera estudiada con patrones variables de la médula a la corteza. Todas estas características tienen efectos indeseables en las propiedades físico-mecánicas y tecnológicas de la madera aserrada para uso estructural. Además, cuanto mayor sea la proporción de JW, mayor incidencia de diferentes distorsiones de secado como el curvado de canto, curvado de cara y alabeo lo que resulta en una disminución en las perspectivas de renta de uso final y retorno económico de los productos aserrados estructurales. Se han dado diferentes nombres a estas dos áreas, las cuales se pueden diferenciar en la dirección transversal del árbol a cualquier altura. También se han expuesto diferentes explicaciones al porqué de dichas variaciones. Si se considera la variación longitudinal, la nomenclatura generalmente empleada es madera interior (CW) y madera exterior (OW). Pero en esta Tesis, utilizaremos la nomenclatura JW/MW, ya que en el sector industrial español es la nomenclatura que se utiliza. Hay varios estudios que evalúan la importancia de la madera juvenil para la madera aserrada estructural en España. Pero no se han realizado muchos estudios sobre las coníferas mediterráneas sobre el efecto de la silvicultura en la cantidad de JW presente en el tronco. La gravedad específica, el MFA y la densitometría se han utilizado ampliamente como indicadores de presencia de JW. En esta Tesis se estudian diferentes metodologías para la determinación de JW en Pinus nigra y Pinus sylvestris con diferente gestión selvícola y esos resultados se comparan con los obtenidos mediante densitometría. Se estudia la influencia de la silvicultura en el TY, en masas de pino laricio y pino silvestre en España, obtenido mediante densitometría. Este análisis se realiza utilizando un modelo mixto lineal segmentado que incluye el análisis de los diferentes efectos, de las covariables incluidas en los diferentes modelos, sobre la densidad. También se estudian las variaciones en el volumen JW y la conicidad de árbol producidas en función de las prácticas selvícolas utilizando la variación radial de densidad de la madera de verano (LW). Otro objetivo de la tesis es la comprobación de si a la altura basal es posible estimar un TY, por medio de la curva de crecimiento acumulado en altura anual y que éste esté relacionado con el obtenido mediante densidad media y de LW anual. Se evalúa la viabilidad de utilizar espectroscopía de infrarrojo cercano (NIR) multipunto, para diferenciar entre JW y MW. Del mismo modo, se evalúa el potencial de las imágenes hiperespectrales de infrarrojo cercano (NIR-HI) para la identificación semiautomática de las áreas de JW y MW en el pino silvestre. Finalmente se estudian los patrones de contracción radial y angular en la dirección transversal a lo largo de diferentes alturas del tronco. En base a los resultados sobre las contracciones, las áreas de JW y MW obtenidas, se relacionaron con las obtenidas a través de la densitometría. Cuando se evalúa el área de JW en un tronco, la micro densitometría de rayos X es un método adecuado para su estudio, los resultados mostraron que la mejor característica de densidad para la automatización del proceso es la densidad de la LW. Si la determinación del TY se realiza mediante datos de cores, que se pueden extraer sobre los árboles en pie, es necesario que la médula necesita esté en el core para evaluar el límite correctamente. La función desarrollada para la realización de los modelos mixtos segmentados proporciona una herramienta potente y más robusta para predecir el TY en un gran número de muestras, en vez de hacerlo individualmente, utilizando perfiles de densidad de LW. El índice de sequía es relevante para el modelado ya que afecta a la densidad de la LW, a la pendiente de la MW o a la determinación del TY. Hasta una altura de 9 metros el TY se produjo antes de la implementación de cualquier tratamiento silvícola, por lo que es necesario hacer otro muestreo en otra masa en la que se hubiesen hecho los tratamientos antes, para evaluar si algún tratamiento pudiera influir o cambiar el TY fuera de la parte del tronco bajo influencia de la copa. Sin embargo, dentro de la copa y en el caso de PN, se demustra que la poda afecta al TY porque la densidad de la LW a la que se alcanza aumenta, retrasando así el TY y aumentando la densidad de la LW. En ambas especies de pino, las claras parecen tener un efecto negativo significativo, aunque pequeño, sobre la densidad de la LW, mientras que los clareos y la poda combinados parecen tener un pequeño efecto positivo en ella, en comparación con el grupo de control. Estos resultados presentados aquí pueden variar dependiendo de la intensidad y el momento de la clara, así como de la cantidad de poda verde llevada a cabo. La respuesta al crecimiento después de los tratamientos silvícolas muestra que la cantidad de JW se reduce en porcentaje, ya que aumenta el volumen total del tronco con cualquier tratamiento selvícola aplicado, para ambas especies, en los bosques puros mediterráneos. El TY calculado utilizando las funciones de crecimiento Chapman-Richards en los incrementos de altura acumulados, no se ajusta a la estimación del TY obtenido a través de la densidad para las procedencias españolas estudiadas de pino silvestre y laricio. Respecto a la calibración entre las mediciones obtenidas con NIR multipunto y los datos de densidad derivados de la micro densitometría de rayos X, ha sido difícil y no se han obtenido resultados lo suficientemente buenos. Por otro lado, el NIR-HI se puede calibrar con los resultados de la micro densitometría de rayos X y la JW, MW y el punto de transición (TP) entre ambos, se puede determinar en la sección transversal del árbol. Los resultados son independientes del tratamiento silvícola aplicado en las plantaciones de pino silvestre estudiadas. El análisis de componentes principales resultó ser una manera útil y fácil de proporcionar información adicional sobre la presencia y ubicación de la madera de compresión. El uso de regresiones de mínimos cuadrados parciales, en nuestro caso, fue la mejor solución para la detección del TP entre JW y MW, cuando la madera de primavera (EW) y la LW se evaluaron por separado. Cada laminilla se clasificó con una diferencia de ±1 anillo en comparación con la obtenida mediante densidad de la LW. Las mayores diferencias fueron de ± 2 de anillos. Una clasificación automática mediante una combinación con una clasificación no supervisada de k-medias anterior entre la EW y la LW, probablemente mejoraría los resultados y podría conducir a una mejor automatización. La contracción radial tiende a ser mayor en los primeros 8 anillos cercanos a la médula, generalmente entre 4 y 9% en los primeros anillos disminuyendo hasta que se estabiliza alrededor del 3%. En cuanto a la contracción angular, es cercana al 0% o incluso negativa cerca de la médula y va aumentando hasta un cierto anillo (9-11), cuando se vuelve más o menos estable alrededor del 2%. Estos resultados son válidos a lo largo del tronco, siendo mayores y la transición producida antes en la contracción radial que angular para cada altura estudiada. No se observan patrones generales a lo largo del mismo árbol en las diferentes alturas muestreadas. La aplicación de los tratamientos silvícolas parece que no tienen ninguna influencia en las variaciones de contracción radial y angular. Si la densidad no es un problema para a clasificación de resistencia de la madera aserrada de uso estructural, el volumen con respecto al área donde la contracción es estable sugiere que, si la contracción longitudinal sigue un patrón similar, el área que podría ser segregada para una mayor calidad es más grande que la proporcionada por la variación radial de densidad de madera de verano

Wireless sensors and IoT platform for intelligent HVAC control

Energy consumption of buildings (residential and non-residential) represents approximately 40% of total world electricity consumption, with half of this energy consumed by HVAC systems. Model-Based Predictive Control (MBPC) is perhaps the technique most often proposed for HVAC control, since it offers an enormous potential for energy savings. Despite the large number of papers on this topic during the last few years, there are only a few reported applications of the use of MBPC for existing buildings, under normal occupancy conditions and, to the best of our knowledge, no commercial solution yet. A marketable solution has been recently presented by the authors, coined the IMBPC HVAC system. This paper describes the design, prototyping and validation of two components of this integrated system, the Self-Powered Wireless Sensors and the IOT platform developed. Results for the use of IMBPC in a real building under normal occupation demonstrate savings in the electricity bill while maintaining thermal comfort during the whole occupation schedule.QREN SIDT [38798]; Portuguese Foundation for Science & Technology, through IDMEC, under LAETA [ID/EMS/50022/2013

Recent techniques used in home energy management systems: a review

Power systems are going through a transition period. Consumers want more active participation in electric system management, namely assuming the role of producers–consumers, prosumers in short. The prosumers’ energy production is heavily based on renewable energy sources, which, besides recognized environmental benefits, entails energy management challenges. For instance, energy consumption of appliances in a home can lead to misleading patterns. Another challenge is related to energy costs since inefficient systems or unbalanced energy control may represent economic loss to the prosumer. The so-called home energy management systems (HEMS) emerge as a solution. When well-designed HEMS allow prosumers to reach higher levels of energy management, this ensures optimal management of assets and appliances. This paper aims to present a comprehensive systematic review of the literature on optimization techniques recently used in the development of HEMS, also taking into account the key factors that can influence the development of HEMS at a technical and computational level. The systematic review covers the period 2018–2021. As a result of the review, the major developments in the field of HEMS in recent years are presented in an integrated manner. In addition, the techniques are divided into four broad categories: traditional techniques, model predictive control, heuristics and metaheuristics, and other techniques.info:eu-repo/semantics/publishedVersio