2,456 research outputs found

    A transferable ab-initio based force field for aqueous ions

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    We present a new polarizable force field for aqueous ions (Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, Sr2+ and Cl-) derived from condensed phase ab-initio calculations. We use Maximally Localized Wannier Functions together with a generalized force and dipole-matching procedure to determine the whole set of parameters. Experimental data is then used only for validation purposes and a good agreement is obtained for structural, dynamic and thermodynamic properties. The same procedure applied to crystalline phases allows to parametrize the interaction between cations and the chloride anion. Finally, we illustrate the good transferability of the force field to other thermodynamic conditions by investigating concentrated solutions.Comment: 31 pages, 8 figure

    Region-based memetic algorithm with archive for multimodal optimisation.

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    In this paper we propose a specially designed memetic algorithm for multimodal optimisation problems. The proposal uses a niching strategy, called region-based niching strategy, that divides the search space in predefined and indexable hypercubes with decreasing size, called regions. This niching technique allows our proposal to keep high diversity in the population, and to keep the most promising regions in an external archive. The most promising solutions are improved with a local search method and also stored in the archive. The archive is used as an index to effiently prevent further exploration of these areas with the evolutionary algorithm. The resulting algorithm, called Region-based Memetic Algorithm with Archive, is tested on the benchmark proposed in the special session and competition on niching methods for multimodal function optimisation of the Congress on Evolutionary Computation in 2013. The results obtained show that the region-based niching strategy is more efficient than the classical niching strategy called clearing and that the use of the archive as restrictive index significantly improves the exploration efficiency of the algorithm. The proposal achieves better exploration and accuracy than other existing techniques

    Estudio, análisis y desarrollo de una red de distribución de contenido y su algoritmo de redirección de usuarios para servicios web y streaming

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    Esta tesis se ha creado en el marco de la línea de investigación de Mecanismos de Distribución de Contenidos en Redes IP, que ha desarrollado su actividad en diferentes proyectos de investigación y en la asignatura ¿Mecanismos de Distribución de Contenidos en Redes IP¿ del programa de doctorado ¿Telecomunicaciones¿ impartido por el Departamento de Comunicaciones de la UPV y, actualmente en el Máster Universitario en Tecnologías, Sistemas y Redes de Comunicación. El crecimiento de Internet es ampliamente conocido, tanto en número de clientes como en tráfico generado. Esto permite acercar a los clientes una interfaz multimedia, donde pueden concurrir datos, voz, video, música, etc. Si bien esto representa una oportunidad de negocio desde múltiples dimensiones, se debe abordar seriamente el aspecto de la escalabilidad, que pretende que el rendimiento medio de un sistema no se vea afectado conforme aumenta el número de clientes o el volumen de información solicitada. El estudio y análisis de la distribución de contenido web y streaming empleando CDNs es el objeto de este proyecto. El enfoque se hará desde una perspectiva generalista, ignorando soluciones de capa de red como IP multicast, así como la reserva de recursos, al no estar disponibles de forma nativa en la infraestructura de Internet. Esto conduce a la introducción de la capa de aplicación como marco coordinador en la distribución de contenido. Entre estas redes, también denominadas overlay networks, se ha escogido el empleo de una Red de Distribución de Contenido (CDN, Content Delivery Network). Este tipo de redes de nivel de aplicación son altamente escalables y permiten un control total sobre los recursos y funcionalidad de todos los elementos de su arquitectura. Esto permite evaluar las prestaciones de una CDN que distribuya contenidos multimedia en términos de: ancho de banda necesario, tiempo de respuesta obtenido por los clientes, calidad percibida, mecanismos de distribución, tiempo de vida al utilizar caching, etc. Las CDNs nacieron a finales de la década de los noventa y tenían como objetivo principal la eliminación o atenuación del denominado efecto flash-crowd, originado por una afluencia masiva de clientes. Actualmente, este tipo de redes está orientando la mayor parte de sus esfuerzos a la capacidad de ofrecer streaming media sobre Internet. Para un análisis minucioso, esta tesis propone un modelo inicial de CDN simplificado, tanto a nivel teórico como práctico. En el aspecto teórico se expone un modelo matemático que permite evaluar analíticamente una CDN. Este modelo introduce una complejidad considerable conforme se introducen nuevas funcionalidades, por lo que se plantea y desarrolla un modelo de simulación que permite por un lado, comprobar la validez del entorno matemático y, por otro lado, establecer un marco comparativo para la implementación práctica de la CDN, tarea que se realiza en la fase final de la tesis. De esta forma, los resultados obtenidos abarcan el ámbito de la teoría, la simulación y la práctica.Molina Moreno, B. (2013). Estudio, análisis y desarrollo de una red de distribución de contenido y su algoritmo de redirección de usuarios para servicios web y streaming [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/31637TESI

    “Aplicación de la metodología PMBOK para mejorar la productividad en la fabricación de tanques en fibra de vidrio de la Empresa FRP Engineering S.A.C en el año 2014”

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    El presente trabajo de investigación es de tipo cuantitativo, pre-experimental, cuyo objetivo es demostrar la mejora de la productividad aplicando la metodología PMBOK en los procesos para la fabricación de tanques en fibra de vidrio en la empresa FRP Engineering S.A.C. Se utilizó la Guía de los Fundamentos para la Dirección de Proyectos (Guía del PMBOK)- Quinta Edición. La muestra estuvo conformada por 30 tanques de fibra de vidrio fabricados durante el año 2014 a quienes se les desarrollara los procesos de gestión necesarios para poder incrementar la productividad. Los datos recolectados fueron procesados y analizados empleando el programa Excel 2010. El porcentaje de productividad de fabricación de tanques en fibra de vidrio incremento en el post test, observándose un 54% de aumento en la productividad de tanques en fibra de vidrio en la empresa FRP Engineering S.A.C, se disminuyó el 35,065% de los costos para la fabricación de tanques en fibra de vidrio y también se redujo el 35,055% del tiempo de fabricación. A través de la prueba estadística T de student se probó, con un nivel de significancia de 5%, que la aplicación de la metodología PMBOK fue eficaz mejorando el nivel de la productividad en la fabricación de tanques en fibra de vidrio en el año 2014

    The INOVE ANR 2010 Blan 0308 project: Integrated approach for observation and control of vehicle dynamics

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    International audienceThis paper presents the INOVE "Integrated approach for observation and control of vehicle dynamics" project. The aim and organization of the project are described and we present some recent results on the proposed integrated approach to design new methodologies for the improvement of the vehicle dynamical behaviour

    Leveraging IoT and prediction techniques to monitor COVID-19 restrictions in port terminals

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    [EN] Social distance restrictions have posed several challenges for the management of logistic nodes even in open spaces like a maritime port terminal. The Internet of Things combined with the simulation of supply chains provide the perfect breeding ground for devising innovative tools to help ports observe those restrictions. The objective of this paper is to devise such a tool based on research open results, proposing a clear architecture and use-case to be leveraged by maritime ports. Internet of Things techniques such as gathering heterogeneous data through a context broker, managing the Big Data generated and applying innovative models over that data set the foundations of the proposed system. The actual tool has been achieved as a result, together with a clear plan on future works that may build upon it.This work is part of the PIXEL project that has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 769355.Vaño, R.; Lacalle, I.; Molina Moreno, B.; Palau Salvador, CE. (2021). Leveraging IoT and prediction techniques to monitor COVID-19 restrictions in port terminals. IEEE. 205-210. https://doi.org/10.1109/WF-IoT51360.2021.959591920521

    Tmprss3 loss of function impairs cochlear inner hair cell Kcnma1 channel membrane expression

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    Before acquiring their mature state, cochlear hair cells undergo a series of changes in expression of ion channels. How this complex mechanism is achieved is not fully understood. Tmprss3, a type II serine protease expressed in hair cells, is required for their proper functioning at the onset of hearing. To unravel the role of Tmprss3 in the acquisition of mature K+ currents, we compared their function by patch-clamp technique in wild-type Tmprss3WT and Tmprss3Y260X-mutant mice. Interestingly, only outward K+ currents were altered in Tmprss3Y260X-mutant mice. To determine by which mechanism this occurred, we compared the protein network of Tmprss3WT and Tmprss3Y260X-mutant mice using proteomic analysis. This led to the identification of a pathway related to potassium Kcnma1 channels. This pathway was validated by immunohistochemistry, focusing on the most downregulated protein that was identified as a cochlear Kcnma1-associated protein, APOA1. Finally, we show that, in contrast to Tmprss3WT, Kcnma1 channels were absent at the neck of inner hair cells (IHCs) in Tmprss3Y260X-mutant mice. In conclusion, our data suggest that lack of Tmprss3 leads to a decrease in Kcnma1 potassium channels expression in (IHCs

    Deep Learning for Automatic Detection and Facial Recognition in Japanese Macaques: Illuminating Social Networks

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    Individual identification plays a pivotal role in ecology and ethology, notably as a tool for complex social structures understanding. However, traditional identification methods often involve invasive physical tags and can prove both disruptive for animals and time-intensive for researchers. In recent years, the integration of deep learning in research offered new methodological perspectives through automatization of complex tasks. Harnessing object detection and recognition technologies is increasingly used by researchers to achieve identification on video footage. This study represents a preliminary exploration into the development of a non-invasive tool for face detection and individual identification of Japanese macaques (Macaca fuscata) through deep learning. The ultimate goal of this research is, using identifications done on the dataset, to automatically generate a social network representation of the studied population. The current main results are promising: (i) the creation of a Japanese macaques' face detector (Faster-RCNN model), reaching a 82.2% accuracy and (ii) the creation of an individual recognizer for K{\=o}jima island macaques population (YOLOv8n model), reaching a 83% accuracy. We also created a K{\=o}jima population social network by traditional methods, based on co-occurrences on videos. Thus, we provide a benchmark against which the automatically generated network will be assessed for reliability. These preliminary results are a testament to the potential of this innovative approach to provide the scientific community with a tool for tracking individuals and social network studies in Japanese macaques

    Changes in serum metabolomics in idiopathic pulmonary fibrosis and effect of approved antifibrotic medication

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    Idiopathic pulmonary fibrosis (IPF) is a progressive disease with significant mortality and morbidity. Approval of antifibrotic therapy has ameliorated disease progression, but therapy response is heterogeneous and to date, adequate biomarkers predicting therapy response are lacking. In recent years metabolomic technology has improved and is broadly applied in cancer research thus enabling its use in other fields. Recently both aberrant metabolic and lipidomic pathways have been described to influence profibrotic responses. We thus aimed to characterize the metabolomic and lipidomic changes between IPF and healthy volunteers (HV) and analyze metabolomic changes following treatment with nintedanib and pirfenidone. We collected serial serum samples from two IPF cohorts from Germany (n = 122) and Spain (n = 21) and additionally age-matched healthy volunteers (n = 16). Metabolomic analysis of 630 metabolites covering 14 small molecule and 12 different lipid classes was carried out using flow injection analysis tandem mass spectrometry for lipids and liquid chromatography tandem mass spectrometry for small molecules. Levels were correlated with survival and disease severity. We identified 109 deregulated analytes in IPF compared to HV in cohort 1 and 112 deregulated analytes in cohort 2. Metabolites which were up-regulated in both cohorts were mainly triglycerides while the main class of down-regulated metabolites were phosphatidylcholines. Only a minority of de-regulated analytes were small molecules. Triglyceride subclasses were inversely correlated with baseline disease severity (GAP-score) and a clinical compound endpoint of lung function decline or death. No changes in the metabolic profiles were observed following treatment with pirfenidone. Nintedanib treatment induced up-regulation of triglycerides and phosphatidylcholines. Patients in whom an increase in these metabolites was observed showed a trend towards better survival using the 2-years composite endpoint (HR 2.46, p = 0.06). In conclusion, we report major changes in metabolites in two independent cohorts testing a large number of patients. Specific lipidic metabolite signatures may serve as biomarkers for disease progression or favorable treatment response to nintedanib
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