Ensemble model-based method for time series sensors’ data validation and imputation applied to a real waste water treatment plant

Intelligent Decision Support Systems (IDSSs) integrate different Artificial Intelligence (AI) techniques with the aim of taking or supporting human-like decisions. To this end, these techniques are based on the available data from the target process. This implies that invalid or missing data could trigger incorrect decisions and therefore, undesirable situations in the supervised process. This is even more important in environmental systems, which incorrect malfunction could jeopardise related ecosystems. In data-driven applications such as IDSS, data quality is a basal problem that should be addressed for the sake of the overall systems’ performance. In this paper, a data validation and imputation methodology for time-series is presented. This methodology is integrated in an IDSS software tool which generates suitable control set-points to control the process. The data validation and imputation approach presented here is focused on the imputation step, and it is based on an ensemble of different prediction models obtained for the sensors involved in the process. A Case-Based Reasoning (CBR) approach is used for data imputation, i.e., similar past situations to the current one can propose new values for the missing ones. The CBR model is complemented with other prediction models such as Auto Regressive (AR) models or Artificial Neural Network (ANN) models. Then, the different obtained predictions are ensembled to obtain a better prediction performance than the obtained by each individual prediction model separately. Furthermore, the use of a meta-prediction model, trained using the predictions of all individual models as inputs, is proposed and compared with other ensemble methods to validate its performance. Finally, this approach is illustrated in a real Waste Water Treatment Plant (WWTP) case study using one of the most relevant measures for the correct operation of the WWTPs IDSS, i.e., the ammonia sensor, and considering real faults, showing promising results with improved performance when using the ensemble approach presented here compared against the prediction obtained by each individual model separately.The authors acknowledge the partial support of this work by the Industrial Doctorate Programme (2017DI-006) and the Research Consolidated Groups/Centres Grant (2017 SGR 574) from the Catalan Agency of University and Research Grants Management (AGAUR), from Catalan Government.Peer ReviewedPostprint (published version

Accurate numerical approach to Quantum Mechanics

Quantum Mechanics is considered as one of the most weird branches in physics with the most, although accurate, counter intuitive predictions. The problem lies not on the theory but on what it is trying to explain: the microscopic world. Moreover, due to the complicated form of the Schrödinger equation, there are only few examples where an analytical solution to the problem exists. Therefore, the motivation of this paper is to explore the effects of Quantum Mechanics solving the Schrödinger equation numerically for different potentials. Firstly, the algorithms and the numerical methods used to calculate the eigenvalues and the eigenstates are explained. Subsequently, on the results section, the numerical system is stressed to find out its precision and the method is used for two real models: the ammonia molecule and the hydrogen atom. Finally, an applet that uses the numerical system of this paper is discussed.2017/201

Application of CBR for intelligent process control of a WWTP

This paper proposes the use of a Case-Based Reasoning (CBR) system for the control and the supervision of a real wastewater treatment plant (WWTP). A WWTP is a critical system which aims to ensure the quality of the water discharged to the receiving bodies, stablished by applicable regulations. At the current stage the proposed methodology has been tested off-line on a real system for the control of the aeration process in the biological treatment of a WWTP within the ambit ofConsorci Besòs Tordera (CBT), a local water administration in the area of Barcelona. For this purpose, data mining methods are considered to extract the available knowledge from historical data to find a useful case base to be able to generate set-points for the local controllers in the WWTP. The results presented in this work are evaluated taking into account the performance of the CBR method e.g. case base size, CBR cycle time or number of cases resolved satisfactorily (forthcoming steps will include on-line tests). For this purpose, some Key Performance Indicators (KPI) are designed together with the plant manager and process experts, in order to monitor key parameters of the WWTP which are representative of the performance of the control and supervision system. Hence, these KPI are related with water quality regulations —e.g. ammonia concentration in the WWTP effluent— and the economic cost efficiency —e.g. electrical consumption of the installation. In order to evaluate the results, different flat-based memory organizations (i.e. cases are stored sequentially in a list) for the case base are considered. First, a unique case base is used. At the current stage and for the results shown in this work, this case base is divided in multiple libraries depending on a case classification. Finally, the combination of this approach with Rule-Based Reasoning (RBR) methods is proposed for the next stages of the work.The authors acknowledge the partial support of this work by the Industrial Doctorate Programme (2017-DI-006) and the Research Consolidated Groups/Centres Grant (2017 SGR 574) from the Catalan Agency of University and Research Grants Management (AGAUR), from Catalan Government.Peer ReviewedPostprint (author's final draft

An interoperable workflow-based framework for the automation of building intelligent process control systems

One of the major problems to design and implement a control/supervision system for a process lies in the need to establish an ad-hoc system for each process installation. On the other side, an open challenge related to the deployment of Intelligent Decision Support Systems (IDSSs) is the interoperability of the different methods used, in order to allow interaction and reuse of different data mining methods and the use of methods based on a model or an expert. Thus, this paper proposes the use of visual workflows, to enable the automation of the design task and the implementation of Intelligent Process Control Systems (IPCSs). The framework will allow the user to specify the design and control of a concrete process as well as the required data-driven and expert models using a graphical workflow environment. The framework is based on a three-layer architecture: first, a comprehensive data science flow description layer (dataflow layer) to produce/discover data-driven models from process data; second, a flowchart of the different components of the process (process-design flow layer) to obtain a simulation model from the design. Finally, the on-line IPCS (process control workflow layer), where the different data-driven models, expert-based models and intelligent reasoning methods interoperate to control and supervise the process. Thus, the resulting system can automatically generate both simulation models of the process and programming code to control and supervise the process, using workflows designed for each particular installation. The case study is focused on the supervision of a Wastewater Treatment Plant (WWTP) located in the Barcelona region.The authors acknowledge the partial support of this work by the Industrial Doctorate Programme (2017-DI-006) and the Research Consolidated Groups/Centres Grant (2017 SGR 574) from the Catalan Agency of University and Research Grants Management (AGAUR), from Catalan Government.Peer ReviewedPostprint (author's final draft

Evaluación de algunas tecnologías para la determinación de los efectos de la gestión del agua de riego y del nitrógeno en frutales

El reg deficitari és una estratègia àmpliament utilitzada quan els recursos d'aigua i energia són escassos i/o cars. La tesi demostra que son possibles altres alternatives de reg i planteja la revisió de algunes de les tecnologies actualment utilitzades per avaluar la eficiència de l’ús d’aigua, tant el la vessant fisiologia com agronòmica i productiva, posant una especial atenció en les interaccions entre els factors del sistema productiu i del procés de producció. Les resultats indiquen que l’eficiència d’us d’aigua no es pot avaluar tant sols com a un model unifactorial. La nutrició té un paper essencial, juntament amb altres activitats del procés en l’eficiència de l’aigua. Paral•lelament, s’analitza l’optimització de l’eficiència d’us d’aigua mitjançant la millora de la qualitat dels fruits. L’evitació de pèrdues i el sosteniment o millora de la qualitat organolèptica son essencials en la gestió del resultats del procés i en l’evitació de pèrdues i sobre costos per noqualitat. La tesi proposa indicadors de qualitat alternatius per aquest propòsit i també en conclou que el maneig del dosser foliar es una valuosa eina tecnològica per augmentar l’eficiència dels recursos a través de la qualitat.El riego deficitario es una estrategia ampliamente utilizada cuando los recursos de agua y energía son escasos y / o caros. La tesis demuestra que son posibles otras alternativas de riego y plantea la revisión de algunas de las tecnologías actualmente utilizadas para evaluar la eficiencia del uso de agua, tanto el la vertiente fisiología como agronómica y productiva, poniendo especial atención en las interacciones entre los factores del sistema productivo y del proceso de producción. Las resultados indican que la eficiencia de uso de agua no se puede evaluar sólo como un modelo unifactorial. La nutrición juega un papel esencial, junto con otras actividades del proceso en la eficiencia del agua. Paralelamente, se analiza la optimización de la eficiencia de uso de agua mediante la mejora de la calidad de los frutos. La evitación de pérdidas y el sostenimiento o mejora de la calidad organoléptica son esenciales en la gestión de los resultados del proceso y en la evitación de pérdidas y sobre costes por no-calidad. La tesis propone indicadores de calidad alternativos para este propósito y también concluye que el manejo del dosel foliar es una valiosa herramienta tecnológica para aumentar la eficiencia de los recursos a través de la calidad.Deficit irrigation is a widely used strategy when energy and water resources are scarce and / or expensive. This thesis demonstrates that alternatives are possible on deficit irrigation. measure of water use efficiency has beeen revisited under a technological, physiological and productive approach, paying particular attention to the interactions between the factors of crop system and production process. The results indicate that water efficiency will not be evaluated only as a univariate model. Nutrition plays an essential role in the efficiency of water use. At the same time,our work discusses the efficiency of water use by improving the quality of the fruit. The avoidance of losses and sustaining or improving the fruit quality are essential in the economic results and for avoidance of non-quality costs. The thesis proposes alternative quality indicators for this purpose and also concludes that the canopy management is an valuable tool for increasing resource efficiency through quality

OFDM and FBMC Performance Comparison for Multistream MIMO Systems

Postprint (published version

Performance comparison between FBMC and OFDM in MIMO systems under channel uncertainty

Postprint (published version

Posterior Wnts have distinct roles in specification and patterning of the planarian posterior region

The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A βcatenin-dependent signal specifies the AP (Anteroposterior) axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts) are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (βcatenin dependent and independent) underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis

Soil porosity changes in orchards with subsurface irrigation: quantification and interpretation

In order to assess the irrigation efficiency under water-limiting conditions, four different treatments of subsurface irrigation of peach trees in a semi-arid Mediterranean climate near Lleida (NE Iberian Peninsula) were tested. The treatments included pressurized air injection, deficit irrigation, full irrigation (as control) and an addition of rice husk around the pipe to improve porosity. Because the latter treatment improved physical conditions and resulted in better tree growth, a micromorphological study was conducted in order to understand the reason for this behaviour. The experiment was carried out in a commercial peach orchard (Prunus persica L.). The soil was a Xeric Torriorthent, with a loam texture, affected by salinity and with low organic matter content. One undisturbed block (30 cm each side) was taken from each treatment, and two vertical thin sections, 5 × 13 cm, including the subsurface pipe, were made. A fluorescent dye was added to the polyester resin to obtain UV light images of the porosity. The pore parameters and the pore size distribution were obtained for each treatment. Strong changes in the pore types of the four treatments are evident in the thin sections. Full and deficit irrigation treatments are characterised by a weakly developed subangular blocky structure, with a vesicular intra-aggregate structure. Deficit irrigation with air injection produced, in its upper part, a structure similar to the full and deficit irrigation treatments. In the surroundings and below the pipe, where the effect of pressurized air was higher, the soil structure is apedal, with vesicles (bubbles), 200 – 500 µm in size. Porosity of the soil modified with rice husk is greater than that of the other three treatments: the 15 – 30 µm porosity fraction is double, and the larger fractions three times that of the other treatments. It contains many oval excrements of mites (probably Oribatidae), 50 – 100 µm in size, associated with moderately decomposed rice husk tissues. We conclude that the modifications around the irrigation pipes that promoted faunal activity are very effective in conveying water to the soil in comparison to that of pressurized air, which only increases vesicular (non connected) porosity.info:eu-repo/semantics/publishedVersio