Energy rating of a water pumping station using multivariate analysis

Among water management policies, the preservation and the saving of energy demand in water supply and treatment systems play key roles. When focusing on energy, the customary metric to determine the performance of water supply systems is linked to the definition of component-based energy indicators. This approach is unfit to account for interactions occurring among system elements or between the system and its environment. On the other hand, the development of information technology has led to the availability of increasing large amount of data, typically gathered from distributed sensor networks in so-called smart grids. In this context, data intensive methodologies address the possibility of using complex network modeling approaches, and advocate the issues related to the interpretation and analysis of large amount of data produced by smart sensor networks. In this perspective, the present work aims to use data intensive techniques in the energy analysis of a water management network. The purpose is to provide new metrics for the energy rating of the system and to be able to provide insights into the dynamics of its operations. The study applies neural network as a tool to predict energy demand, when using flowrate and vibration data as predictor variables

On the use of artificial Intelligence for condition monitoring in horizontal-axis wind turbines

Wind power is one of the fastest-growing renewable energy sectors and is considered instrumental in the ongoing decarbonization process. However, wind turbines (WTs) present high operation and maintenance costs caused by inefficiencies and failures, leading to ever-increasing attention to effective Condition Monitoring (CM) strategies. Nowadays, modern WTs are integrated with sensor networks as part of the Supervisory Control and Data Acquisition (SCADA) system for supervision purposes. CM of wind farms through predictive models based on routinely collected SCADA data is envisaged as a viable mean of improving producibility by spotting operational inefficiencies. In this paper, we introduce an unsupervised anomaly detection framework for wind turbine using SCADA data. It involves the use of a multivariate feature selection algorithm based on a novel Combined Power Predictive Score (CPPS), where the information content of combinations of variables is considered for the prediction of one or more key parameters. The framework has been tested on SCADA data collected from an off-shore wind farm, and the results showed that it successfully detects anomalies and anticipates major bearing failures by outperforming a recent deep neural approach

Matemática, informática y la “renegociación” de normas preexistentes

El deseo de dar respuestas a interrogantes tales como ¿Qué tipo de conocimientos requiere una sociedad en constante transformación?; ¿qué capacidades o estrategias debemos promover para favorecer la formación de individuos social, cultural e intelectualmente plenos, comprometidos con su entorno?. ¿Será posible contemplar en las planificaciones pedagógicas la secuencia evolutiva natural de la vida (ambiente enseñanzas- memorias-comportamiento individual-comportamiento social-enseñanzas-ambiente), los tiempos biológicos requeridos para consolidar, almacenar y dar funcionalidad a la información adquirida?; ¿imponerse a la aceleración (o inercia) de los tiempos administrativos? nos lleva a reflexionar sobre la propia práctica, considerar el rediseño de la misma, a proponernos finalmente un plan de trabajo cuya estructuración contemple tanto cuestiones atinentes a la propia disciplina como, y especialmente, a todas aquellas otras que tuvieran que ver con una positiva integración Sociedad, Ciencia y Tecnología, S/C/T. En una primer etapa procedimos a investigar, caracterizar y explicitar una serie de normas “sociomatemáticas” que llamamos preexistentes y que a nuestro juicio serían inhibidoras del aprendizaje y relativas al contexto sociocultural en el que nos movemos. Por contraposición establecimos normas a renegociar con nuestros estudiantes, las que llamamos “emergentes”. Concretada la primer etapa del plan (sistema de interpretación, diseño de instrumentos para la intervención pedagógica) generamos experiencias participativas con la presencia de estudiantes y docentes a los fines de implementar los instrumentos diseñados, observar y evaluar la calidad de los mismos, el sistema de interpretación en sí. El presente trabajo trata de algunos resultados y conclusiones obtenidas en esta segunda etapa del plan

Las funciones en la resolución de problemas

En este trabajo presentamos algunas reflexiones y una propuesta acerca de la enseñanza por resolución de problemas, siendo el eje de esta última la aplicación y discusión del concepto de Función. En las carreras ´no matemáticas´ sin relegar el papel fundamental de la formación en lo teórico-conceptual los esfuerzos se desplazan hacia la aplicación de los métodos matemáticos en la resolución de problemas de las ciencias en general. Dado que el desarrollo mismo de la ciencia puede entenderse como resultado de la búsqueda de solución a los distintos problemas que aquejan al hombre, creemos que la ´enseñanza por resolución de problemas´ coadyuva a promover el cambio conceptual y metodológico que requiere actualmente el sistema educativo en general. La propuesta consiste esencialmente en el planteo de una situación problemática familiar al estudiante para, a partir de allí y siempre bajo la guía y supervisión del docente, proceder a su discusión, al planteo de conjeturas e hipótesis, resolución, verificación, etc. En este caso el problema requiere del concepto de función, concepto básico y esencial en toda disciplina que acuda a los modelos matemáticos. Creemos que este presenta características que lo signan como concepto fuerza en la implementación del cambio pretendido; que su uso en el marco de la resolución de problemas coadyuva a tal propósito pues, entre otras bondades, las funciones se caracterizan por tener cuatro representaciones o codificaciones distintas -gráfica, numérica, analítica, verbal- cada una de las cuales expresa aspectos o propiedades didácticas no equivalentes ni equiparables entre sí, lo cual, además de ampliar el espectro de posibilidades para trabajar con el estudiante, proporciona elementos para una mejor evaluación del mismo (asimilando la comprensión del concepto a la capacidad de recodificar la información desde una representación a otra)

Thermo-mechanical behavior of surface acoustic waves in ordered arrays of nanodisks studied by near infrared pump-probe diffraction experiments

The ultrafast thermal and mechanical dynamics of a two-dimensional lattice of metallic nano-disks has been studied by near infrared pump-probe diffraction measurements, over a temporal range spanning from 100 fs to several nanoseconds. The experiments demonstrate that, in these systems, a two-dimensional surface acoustic wave (2DSAW), with a wavevector given by the reciprocal periodicity of the array, can be excited by ~120 fs Ti:sapphire laser pulses. In order to clarify the interaction between the nanodisks and the substrate, numerical calculations of the elastic eigenmodes and simulations of the thermodynamics of the system are developed through finite-element analysis. At this light, we unambiguously show that the observed 2DSAW velocity shift originates from the mechanical interaction between the 2DSAWs and the nano-disks, while the correlated 2DSAW damping is due to the energy radiation into the substrate.Comment: 13 pages, 10 figure

Comparative chondrogenesis of human cells in a 3D integrated experimental/computational mechanobiology model

We present an integrated experimental–computational mechanobiology model of chondrogenesis. The response of human articular chondrocytes to culture medium perfusion, versus perfusion associated with cyclic pressurisation, versus non-perfused culture, was compared in a pellet culture model, and multiphysic computation was used to quantify oxygen transport and flow dynamics in the various culture conditions. At 2 weeks of culture, the measured cell metabolic activity and the matrix content in collagen type II and aggrecan were greatest in the perfused+ pressurised pellets. The main effects of perfusion alone, relative to static controls, were to suppress collagen type I and GAG contents, which were greatest in the non-perfused pellets. All pellets showed a peripheral layer of proliferating cells, which was thickest in the perfused pellets, and most pellets showed internal gradients in cell density and matrix composition. In perfused pellets, the computed lowest oxygen concentration was 0.075mM (7.5% tension), the maximal oxygen flux was 477.5 nmol/m2/s and the maximal fluid shear stress, acting on the pellet surface, was 1.8mPa (0.018 dyn/cm2). In the non-perfused pellets, the lowest oxygen concentration was 0.003mM (0.3% tension) and the maximal oxygen flux was 102.4nmol/m2/s.Alocal correlationwas observed, between the gradients in pellet properties obtained from histology, and the oxygen fields calculated with multiphysic simulation. Our results showup-regulation of hyalinematrix protein production by human chondrocytes in response to perfusion associated with cyclic pressurisation. These results could be favourably exploited in tissue engineering applications

Hierarchic Superposition Revisited

Many applications of automated deduction require reasoning in first-order logic modulo background theories, in particular some form of integer arithmetic. A major unsolved research challenge is to design theorem provers that are "reasonably complete" even in the presence of free function symbols ranging into a background theory sort. The hierarchic superposition calculus of Bachmair, Ganzinger, and Waldmann already supports such symbols, but, as we demonstrate, not optimally. This paper aims to rectify the situation by introducing a novel form of clause abstraction, a core component in the hierarchic superposition calculus for transforming clauses into a form needed for internal operation. We argue for the benefits of the resulting calculus and provide two new completeness results: one for the fragment where all background-sorted terms are ground and another one for a special case of linear (integer or rational) arithmetic as a background theory

The case report of a 31-year-old man with giant cell myocarditis successfully treated with combined immunosuppression and veno-arterial extracorporeal membrane oxygenation for 21 days

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New results on rewrite-based satisfiability procedures

Program analysis and verification require decision procedures to reason on theories of data structures. Many problems can be reduced to the satisfiability of sets of ground literals in theory T. If a sound and complete inference system for first-order logic is guaranteed to terminate on T-satisfiability problems, any theorem-proving strategy with that system and a fair search plan is a T-satisfiability procedure. We prove termination of a rewrite-based first-order engine on the theories of records, integer offsets, integer offsets modulo and lists. We give a modularity theorem stating sufficient conditions for termination on a combinations of theories, given termination on each. The above theories, as well as others, satisfy these conditions. We introduce several sets of benchmarks on these theories and their combinations, including both parametric synthetic benchmarks to test scalability, and real-world problems to test performances on huge sets of literals. We compare the rewrite-based theorem prover E with the validity checkers CVC and CVC Lite. Contrary to the folklore that a general-purpose prover cannot compete with reasoners with built-in theories, the experiments are overall favorable to the theorem prover, showing that not only the rewriting approach is elegant and conceptually simple, but has important practical implications.Comment: To appear in the ACM Transactions on Computational Logic, 49 page