4,748 research outputs found

    Non-centralized Control for Flow-based Distribution Networks: A Game-theoretical Insight

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    This paper solves a data-driven control problem for a flow-based distribution network with two objectives: a resource allocation and a fair distribution of costs. These objectives represent both cooperation and competition directions. It is proposed a solution that combines either a centralized or distributed cooperative game approach using the Shapley value to determine a proper partitioning of the system and a fair communication cost distribution. On the other hand, a decentralized noncooperative game approach computing the Nash equilibrium is used to achieve the control objective of the resource allocation under a non-complete information topology. Furthermore, an invariant-set property is presented and the closed-loop system stability is analyzed for the non cooperative game approach. Another contribution regarding the cooperative game approach is an alternative way to compute the Shapley value for the proposed specific characteristic function. Unlike the classical cooperative-games approach, which has a limited application due to the combinatorial explosion issues, the alternative method allows calculating the Shapley value in polynomial time and hence can be applied to large-scale problems.Generalitat de Catalunya FI 2014Ministerio de Ciencia y Educación DPI2016-76493-C3-3-RMinisterio de Ciencia y Educación DPI2008-05818Proyecto europeo FP7-ICT DYMASO

    Los santucos montañeses

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    En número dedicado a: La provincia de Santande

    Software Perfomance Assessment at Architectural Level: A Methodology and its Application

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    Las arquitecturas software son una valiosa herramienta para la evaluación de las propiedades cualitativas y cuantitativas de los sistemas en sus primeras fases de desarrollo. Conseguir el diseño adecuado es crítico para asegurar la bondad de dichas propiedades. Tomar decisiones tempranas equivocadas puede implicar considerables y costosos cambios en un futuro. Dichas decisiones afectarían a muchas propiedades del sistema, tales como su rendimiento, seguridad, fiabilidad o facilidad de mantenimiento. Desde el punto de vista del rendimiento software, la ingeniería del rendimiento del software (SPE) es una disciplina de investigación madura y comúnmente aceptada que propone una evaluación basada en modelos en las primeras fases del ciclo de vida de desarrollo software. Un problema en este campo de investigación es que las metodologías hasta ahora propuestas no ofrecen una interpretación de los resultados obtenidos durante el análisis del rendimiento, ni utilizan dichos resultados para proponer alternativas para la mejora de la propia arquitectura software. Hasta la fecha, esta interpretación y mejora requiere de la experiencia y pericia de los ingenieros software, en especial de expertos en ingeniería de prestaciones. Además, a pesar del gran número de propuestas para evaluar el rendimiento de sistemas software, muy pocos de estos estudios teóricos son posteriormente aplicados a sistemas software reales. El objetivo de esta tesis es presentar una metodología para el asesoramiento de decisiones arquitecturales para la mejora, desde el punto de vista de las prestaciones, de las sistemas software. La metodología hace uso del Lenguaje Unificado de Modelado (UML) para representar las arquitecturas software y de métodos formales, concretamente redes de Petri, como modelo de prestaciones. El asesoramiento, basado en patrones y antipatrones, intenta detectar los principales problemas que afectan a las prestaciones del sistema y propone posibles mejoras para mejoras dichas prestaciones. Como primer paso, estudiamos y analizamos los resultados del rendimiento de diferentes estilos arquitectónicos. A continuación, sistematizamos los conocimientos previamente obtenidos para proponer una metodología y comprobamos su aplicabilidad asesorando un caso de estudio real, una arquitectura de interoperabilidad para adaptar interfaces a personas con discapacidad conforme a sus capacidades y preferencias. Finalmente, se presenta una herramienta para la evaluación del rendimiento como un producto derivado del propio ciclo de vida software

    Osteochemonecrosis of the jaws due to bisphosphonate treatments : update

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    Bisphosphonates (BP),were initially used in industry and later as a drug due to their great affinity to osseous tissue, because of their powerful antiresorptive effect as a treatment in various osteopathies, such as osteoporosis, Paget disease or hypercalcemia associated with some malignant tumors, as myeloma or breast cancer. They are administered orally or intravenously, and although well tolerated, the most frequent side effects are gastrointestinal, in addition to osteonecrosis when they are administered via endovenous. The aim of this work has been to evaluate the existing publications in accredited scientific literature on biphosphonates and their action mechanism and the relationship with the appearance of osteonecrosis of the jaws. Although the mechanism by which osteonecrosis of the jaws develops is not known exactly, there seems to be influence by osteoclast inhibiton, antiangiogenic action, an inhibitory effect on the cellular cycle by the keratinocytes, as well as, reinforcement of the chemiotoxic action in oncological patients treated with other drugs. Clinically, it ranges from a non-specificity of symptoms to lesions such as osteomyelitis with necrosis and osseous sequesters that may be accompanied by fetor ex oris, with the appearance of many Actinomyces contaminated lesions. As for published antecedents on osteonecrosis due to bisphosphonate treatment found until 2006: 46.5% had a previous diagnosis of multiple myeloma; 38.8% were patients with metastatic breast cancer; 6.2% patients of metastatic prostate cancer; 4.1% suffered from osteoporosis; 3.5% from other metastatic diseases and 0.8% had Paget disease. The drugs that seem to have the highest incidence of osteochemionecrosis are: zoledronate, pamidronate, alendronate, risendronate and ibandronate, from the greatest to the least. Additionally, the risk of osteonecrosis being produced is accumulative and may reach 21% in the third year of intravenous bisphosphonate use

    Performance assessment of an architecture with adaptative interfaces for people with special needs

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    People in industrial societies carry more and more portable electronic devices (e.g., smartphone or console) with some kind of wireles connectivity support. Interaction with auto-discovered target devices present in the environment (e.g., the air conditioning of a hotel) is not so easy since devices may provide inaccessible user interfaces (e.g., in a foreign language that the user cannot understand). Scalability for multiple concurrent users and response times are still problems in this domain. In this paper, we assess an interoperable architecture, which enables interaction between people with some kind of special need and their environment. The assessment, based on performance patterns and antipatterns, tries to detect performance issues and also tries to enhance the architecture design for improving system performance. As a result of the assessment, the initial design changed substantially. We refactorized the design according to the Fast Path pattern and The Ramp antipattern. Moreover, resources were correctly allocated. Finally, the required response time was fulfilled in all system scenarios. For a specific scenario, response time was reduced from 60 seconds to less than 6 seconds

    Energy Efficiency of Hybrid-Power HetNets: A Population-like Games Approach

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    In this paper, a distributed control scheme based on population games is proposed. The controller is in charge of dealing with the energy consumption problem in a Heterogeneous Cellular Network (HetNet) powered by hybrid energy sources (grid and renewable energy) while guaranteeing appropriate quality of service (QoS) level at the same time. Unlike the conventional approach in population games, it considers both atomicity and non-anonymity. Simulation results show that the proposed population-games approach reduces grid consumption by up to about 12% compared to the traditional best-signal level association policy.U.S. Air Force Office of Scientific Research FA9550-17-1-0259Ministerio de Cultura y Deporte DPI2016-76493-C3-3-RMinisterio de Economía y Empresa DPI2017-86918-

    Photocatalytic degradation and mineralization of perfluorooctanoic acid (PFOA) using a composite TiO2 -rGO catalyst

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    The inherent resistance of perfluoroalkyl substances (PFASs) to biological degradation makes necessary to develop advanced technologies for the abatement of this group of hazardous substances. The present work investigated the photocatalytic decomposition of perfluorooctanoic acid (PFOA) using a composite catalyst based on TiO2 and reduced graphene oxide (95% TiO2/5% rGO) that was synthesized using a facile hydrothermal method. The efficient photoactivity of the TiO2-rGO (0.1 g L-1) composite was confirmed for PFOA (0.24 mmol L-1) degradation that reached 93 ± 7% after 12 h of UV-vis irradiation using a medium pressure mercury lamp, a great improvement compared to the TiO2 photocatalysis (24 ± 11% PFOA removal) and direct photolysis (58 ± 9%). These findings indicate that rGO provided the suited properties of TiO2-rGO, possibly as a result of acting as electron acceptor and avoiding the high recombination electron/hole pairs. The release of fluoride and the formation of shorter-chain perfluorocarboxilyc acids, that were progressively eliminated in a good match with the analysed reduction of total organic carbon, is consistent with a step-by-step PFOA decomposition via photogenerated hydroxyl radicals. Finally, the apparent first order rate constants of the TiO2-rGO UV-vis PFOA decompositions, and the intermediate perfluorcarboxylic acids were found to increase as the length of the carbon chain was shorter.Financial support from projects CTM2013-44081-R, CTM2015-69845-R and CTM2016-75509-R (MINECO, SPAIN-FEDER 2014–2020) is acknowledged. B. Gomez thanks the FPI scholarship (BES-2014-071045)

    Influencia del ciclo económico sobre los determinantes de la actividad emprendedora naciente. Un análisis empírico del caso español

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    This paper explores the contribution of a selection of elements representative of human capital and perception as determinants of entrepreneurship in different stages of the economic cycle. The results confirm the significance of selfefficacy, the perception of opportunities, and the fear of failure, and highlight the importance of personal knowledge of entrepreneurs. They remain influential in different economic times in which their analyses have been replicated, although some differences are felt that point to, in contraction periods, a loss of influence of the confidence in one’s own abilities, compared to an increase in the case of judgment on the existence of opportunities in the environment, and in the case of the presence of entrepreneurs in the surrounding context. In contrast, the behavior of the fear of failure, as a barrier to entrepreneurship, remains unchanged in an adverse context with respect to a positive context due to reduced opportunity costs.Este trabajo explora la contribución de una selección de elementos representativos de capital humano y de percepción como determinantes de la creación de empresas ante distintas etapas del ciclo económico. Los resultados confirman la significación de la autoeficacia, la percepción de oportunidades y el miedo al fracaso, y resaltan la importancia del conocimiento de emprendedores. Su influencia se mantiene en los distintos momentos económicos en los que se han replicado los análisis, si bien se intuyen algunas diferencias que apuntan, en etapas contractivas, a una pérdida de influencia de la confianza en las propias habilidades, frente a un incremento en el caso del juicio sobre la existencia de oportunidades en el entorno y en el caso de la presencia de emprendedores en el contexto cercano. En cambio, el comportamiento del miedo a fracasar, como barrera para emprender, se mantiene invariable en un contexto adverso respecto a uno positivo debido a la reducción de costes de oportunidad

    La justificación de las condiciones de trabajo y demandas laborales en España: órdenes de valor

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    In this article, the dominant legitimating discursive strategies around the ever-increasing labour demands and ever-declining standards of safety and well-being at work in Spain are analysed through the lens of Boltanski and Thévenot’s (2006) view of the transfor-mation of capitalism. A qualitative methodology based on semi-structured interviews is used. Results show that the justificatory arguments most commonly put forward by managers and experts are the logic of supply and demand, and values related to flexibility, resilience and adaptability to change. In contrast, the stability and protection established in the twentieth century are widely cherished values, particularly among union representatives and some human resources specialists. We found that discourse practices map two specific legitimating categories (market values and a projects orientation), and one critical category (Civic World), but the critical category has no practical impact, as the predominant feeling is resig-nation. Our research describes the common attitudes to legitimacy in the job market and points to a deep discontent in some of its key agents.En este artículo se analizan, bajo la lente de la crítica de Boltanskiy Thevenot (2006) sobre la transformación del capitalismo, las estrategias de legitimación que dominan los discursos sobre las siempre crecientes demandas laborales y las cada vez más precarias condiciones de trabajo en España. Para la investigación se usó una metodología cualitativa a través de entrevistas semiestructuradas. Como resultado, se puede afirmar que los argumentos justificadores más utilizados son los relacionados con la lógica de oferta y demanda, así como con los valores de flexibilidad, resiliencia y adaptabilidad al cambio, sobre todo por parte de directivos y expertos. Entretanto, los valores de estabilidad y protección característicos del siglo XX son los más preciados por sindicalistas y técnicos en RR. HH. Encontramos que las prácticas discursivas se corresponden con dos categorías legitimadoras —los valores del mercado y la orientación a proyectos— y una categoría crítica —el mundo cívico— que, sin embargo, carece de eficacia práctica, siendo el sentimiento más generalizado el de resignación. Con esta investigación se describen empíricamente las actitudes comunes sobre la legitimidad en el mercado de trabajo y queda patente un profundo descontento en algunos de sus agentes principales.Grant BES-2015-073179 and Grants FFI2014-56391-P and FFI2017-87953-R from the Spanish Ministry of Economy and Competitiveness, National Plan of Scientific and Technical Research and Innovation
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