Model predictive control techniques for hybrid systems

This paper describes the main issues encountered when applying model predictive control to hybrid processes. Hybrid model predictive control (HMPC) is a research field non-fully developed with many open challenges. The paper describes some of the techniques proposed by the research community to overcome the main problems encountered. Issues related to the stability and the solution of the optimization problem are also discussed. The paper ends by describing the results of a benchmark exercise in which several HMPC schemes were applied to a solar air conditioning plant.Ministerio de Eduación y Ciencia DPI2007-66718-C04-01Ministerio de Eduación y Ciencia DPI2008-0581

Single-layer economic model predictive control for periodic operation

In this paper we consider periodic optimal operation of constrained periodic linear systems. We propose an economic model predictive controller based on a single layer that unites dynamic real time optimization and control. The proposed controller guarantees closed-loop convergence to the optimal periodic trajectory that minimizes the average operation cost for a given economic criterion. A priori calculation of the optimal trajectory is not required and if the economic cost function is changed, recursive feasibility and convergence to the new periodic optimal trajectory is guaranteed. The results are demonstrated with two simulation examples, a four tank system, and a simplified model of a section of Barcelona's water distribution network.Peer ReviewedPostprint (author’s final draft

Detección de videos modificados por la técnica de intercambio de identidad DeepFake

"Durante la aparición del algoritmo DeepFake, entre los años 2017 a 2019, el 96% de los videos generados por este, eran de naturaleza pornográfica. Con la aparición de aplicaciones móviles, al alcance de cualquier usuario, que generan estos videos, y la creciente preocupación de empresas como Facebook por dichos videos, surge la necesidad de herramientas que determinen si un video es real o generado por intercambio de identidad. Esta tesis muestra una revisión de los trabajos más relevantes en este tema, presenta la propuesta de un sistema y detalla los elementos que lo conforman. También define los parámetros necesarios para optimizar dichos elementos. Además de presentar una alternativa para entrenar modelos que excedan la potencia de cómputo. Los experimentos realizados reportan un AUC promedio de 0.9968, comparable al estado del arte"

Profitability of olive mill pomace composting as a bioeconomy alternative

La bioeconomía circular está muy presente en la agenda política actual, como consecuencia de la preocupación de la sociedad por el medio ambiente. Este nuevo paradigma se presenta como una oportunidad para el sector del olivar y de los aceites de oliva, dada la gran cantidad de subproductos que genera y su potencial de valorización. Entre las alternativas existentes para la valorización del alperujo y el hojín producido en las almazaras, el compostaje se presenta como una alternativa técnicamente viable, a pesar de lo cual su implantación es escasa. El objetivo de este estudio es analizar la rentabilidad financiera del compostaje de subproductos de la almazara, identificar los principales factores que la determinan y realizar un análisis de sensibilidad de estos. Para ello, se ha analizado la inversión necesaria y los costes de explotación de la actividad de compostaje, arrojando como resultado un margen comercial negativo (-3,64 €/t de compost), considerando la situación actual. No obstante, el margen comercial pasa a ser positivo (+9,52 €/t de compost) al no considerar el coste de oportunidad relativo a la venta del alperujo a la extractora. El análisis de sensibilidad indica que el precio de dicha venta, el precio del combustible y el precio del estiércol son los principales factores limitantes para la rentabilidad de la actividad. Asimismo, se incluye un análisis pormenorizado del efecto de la distancia a la extractora sobre el coste de producción del compost, obteniéndose que para distancias superiores a los 54 km el margen comercial es positivo.The circular bioeconomy is top-ranked among the priorities of the political agenda due to society's concern for the environment. This new paradigm is presented as an opportunity for the olive oil sector due to the large quantities of by products generated and their potential for valorization. Among the existing alternatives for valorizing olive pomace and olive leaves produced in olive mills, composting is presented as a technically feasible alternative, although its implementation is scarce. This study aims to analyze the financial profitability for olive mills of by-products composting, identify the main factors that determine this profitability, and conduct a sensitivity analysis regarding these factors. For this purpose, the investment and operating costs required for the composting activity have been assessed, determining that, under the current situation, the commercial margin of the activity is negative (−€3.64/t of compost). Without considering the sale price of olive pomace to the extractor industry (which represents an opportunity cost for other valorization alternatives, like composting), the commercial margin is estimated to be positive (+€9.52/t of compost). The sensitivity analysis has shown that fuel price, the sale price of the olive pomace to the extractor industry, and the manure price are the main limiting factors for the profitability of the composting valorization alternative. A detailed analysis of the effect of the distance to the pomace oil extraction industry on the cost of the compost produced was also carried out, showing that the commercial margin is positive for distances greater than 54 km

Enhancing Singlet Oxygen Generation by Self-Assembly of a Porphyrin Entrapped in Supramolecular Fibers

Singlet oxygen (SO) is one of the reactive oxygen species that is effective in various uses, including performing chemical reactions, treating water impurities, and aiding in medicinal therapy. The generation of SO is often efficient in solution, although generation from the solid phase in nanomaterials is less reliable. Here, we report the preparation of hybrid supramolecular materials that incorporate a photosensitizer within their nanostructured fibers and demonstrate their high efficiency in promoting SO formation. The incorporation of tetrakis(4-carboxyphenyl)porphyrin within the nanofibers of a bis-imidazolium gelator was proved by various techniques, including super-resolution radial fluctuations (SRRF) microscopy, which shows the location of the chromophore precisely. SO is generated from the dispersed nanofibers far more efficiently than the dissolved porphyrin; a 14-fold higher rate is observed initially. These results point to an effective approach to the generation of SO for several applications, from optimizing synthetic protocols to photomedicine

Oracle-based economic predictive control

Article number 107434This paper presents an economic model predictive controller, under the assumption that the only mea- surable signal of the plant is the economic cost to be minimized. In order to forecast the evolution of this economic cost for a given input trajectory, a prediction model with a NARX structure, the so-called oracle, is proposed. Sufficient conditions to ensure the existence of such oracle are studied, proving that it can be derived for a general nonlinear system if the economic cost function is a Morse function. Based on this oracle, economic model predictive controllers are proposed, and their stability is demonstrated in nominal conditions under a standard dissipativity assumption. The viability of these controllers in practi- cal settings (where the oracle may provide imperfect predictions for generic inputs) is proven by means of input-to-state stability. These properties have been illustrated in a case study based on a continuously stirred tank reactorMinisterio de Economía y Competitividad (MINECO). España DPI2016-76493-C3-1-RAgencia Estatal de Investigación (AEI) PID2019-106212RB-C41/AEI/10.13039/50110001103

Microscale coiling in bis-imidazolium supramolecular hydrogel fibres induced by release of a cationic serine protease inhibitor

Gels formed by a gemini dicationic amphiphile incorporate a serine protease inhibitor, which could be used in a new approach to the treatment of Rosacea, within the fibres as well as in the space between them, affecting a number of gel properties but most importantly inducing remarkable fibre coiling at the microscopic level as a result of drug release from the gel. Drug release and skin permeation experiments show its potential for topical administration

Desarrollo de recursos educativos para Ingeniería del Software utilizando repositorios de Open Data y Linked Data

En este trabajo se desarrolla una herramienta capaz de gestionar recursos educativos de la asignatura Ingeniería del Software. Existen tres roles diferentes, alumno, profesor y administrador donde cada uno tiene su propia interfaz. El administrador es el encargado de gestionar la herramienta y las cuentas de los profesores. El profesor es quien genera recursos en la herramienta, se le ofrece la posibilidad de completar dichos recursos con repositorios obtenidos a través de Open Data y Linked Data. Además, puede gestionar los alumnos pertenecientes a su grupo. El alumno tiene la capacidad de interaccionar con estos recursos, visualizando y descargando el contenido de estos

An interventional nationwide surveillance program lowers postoperative infection rates in elective colorectal surgery: a cohort study (2008–2019)

Colorectal surgery; Postoperative infection; Cohort studiesCirugía colorrectal; Infección postoperatoria; Estudios de cohortesCirurgia colorectal; Infecció postoperatòria; Estudis de cohortsBackground: Colorectal surgery is associated with the highest rate of surgical site infection (SSI). This study analyses the effectiveness of an interventional surveillance program on SSI rates after elective colorectal surgery. Material and methods: Cohort study showing temporal trends of SSI rates and Standardized Infection Ratio (SIR) in elective colorectal surgery over a 12-year period. Prospectively collected data of a national SSI surveillance program was analysed and the effect of specific interventions was evaluated. Patient and procedure characteristics, as well as SIR and SSI rates were stratified by risk categories and type of SSI analysed using stepwise multivariate logistic regression models. Results: In a cohort of 42,330 operations, overall cumulative SSI incidence was 16.31%, and organ-space SSI (O/S-SSI) was 8.59%. There was a 61.63% relative decrease in SSI rates (rho = -0.95804). The intervention which achieved the greatest SSI reduction was a bundle of 6 measures. SSI in pre-bundle period was 19.73% vs. 11.10% in post-bundle period (OR 1.969; IC 95% 1.860-2.085; p < 0.0001). O/S-SSI were 9.08% vs. 6.06%, respectively (OR 1.547; IC 95% 1.433-1.670; p < 0.0001). Median length of stay was 7 days, with a significant decrease over the studied period (rho = -0.98414). Mortality of the series was 1.08%, ranging from 0.35% to 2.0%, but a highly significant decrease was observed (rho = -0.67133). Conclusions: Detailed analysis of risk factors and postoperative infection in colorectal surgery allows strategies for reducing SSI incidence to be designed. An interventional surveillance program has been effective in decreasing SIR and SSI rates