4,470 research outputs found

    A New Strategy to Improve the Performance of PDP-Systems Simulators

    Get PDF
    One of the major challenges that current P systems simulators have to deal with is to be as efficient as possible. A P system is syntactically described as a membrane structure delimiting regions where multisets of objects evolve by means of evolution rules. According to that, on each computation step, the applicability of the rules for the current P system configuration must be calculated. In this paper we extend previous works that use Rete-based simulation algorithm in order to improve the time consumed during the checking phase in the selection of rules. A new approach is presented, oriented to the acceleration of Population Dynamics P Systems simulations.Ministerio de Economía y Competitividad TIN2012- 3743

    High‐performance liquid chromatography with fluorescence detection fingerprints as chemical descriptors to authenticate the origin, variety and roasting degree of coffee by multivariate chemometric methods

    Get PDF
    BACKGROUND: Coffee is one of the most popular beverages around the world, consumed as an infusion of ground roasting coffee beans with a characteristic taste and flavor. Two main varieties, Arabica and Robusta, are worldwide produced. Besides, the interest of consumers in quality attributes related to coffee production region and varieties is increasing, being necessary encouraging the development of simple methodologies to authenticate and to guarantee the coffee origin, variety, as well as the roasting degree to prevent fraudulent practices. RESULTS: C18 high-performance liquid chromatography with fluorescence detection (HPLC-FLD) fingerprints obtained after brewing the coffees without any sample treatment other than filtration (considerably reducing sample manipulation) were employed as sample chemical descriptors for coffee characterization and classification by principal component analysis (PCA) and partial least squares regression-discriminant analysis (PLS-DA). PLS-DA showed good classification capabilities regarding coffee origin, variety and roasting degree when employing HPLC-FLD fingerprints although overlapping for some sample groups occurred. However, the discrimination power increased when selecting HPLC-FLD fingerprinting segments richer in discriminant features, which were deduced from PLS-DA loading plots. In this case, excellent separation was observed and 100% classification rates for both PLS-DA calibrations and predictions were obtained (all samples were correctly classified within their corresponding groups). CONCLUSION: HPLC-FLD fingerprinting segments resulted to be suitable chemical descriptors to discriminate the origin (country of production), variety (Arabica and Robusta) and roasting degree of coffee. Therefore, HPLC-FLD fingerprinting can be proposed as a feasible, simple and cheap methodology to address coffee authentication, especially for developing coffee production countries

    Large lianas as hyperdynamic elements of the tropical forest canopy

    Get PDF
    Lianas (woody vines) are an important component of lowland tropical forests. We report large liana and tree inventory and dynamics data from Amazonia over periods of up to 24 years, making this the longest geographically extensive study of liana ecology to date. We use these results to address basic questions about the ecology of large lianas in mature forests and their interactions with trees. In one intensively studied site we find that large lianas (≥10 cm diameter) represent ,5% of liana stems, but 80% of biomass of well-lit upper canopy lianas. Across sites, large lianas and large trees are both most successful in terms of structural importance in richer soil forests, but large liana success may be controlled more by the availability of large tree supports rather than directly by soil conditions. Long-term annual turnover rates of large lianas are 5–8%, three times those of trees. Lianas are implicated in large tree mortality: liana-infested large trees are three times more likely to die than liana-free large trees, and large lianas are involved in the death of at least 30% of tree basal area. Thus large lianas are a much more dynamic component of Amazon forests than are canopy trees, and they play a much more significant functional role than their structural contribution suggests

    Using classical control theory for node buffer control of delay tolerant networks

    Get PDF
    Els satèl·lits no tenen un comportament autònom pel que fa a l'adquisició i transmissió de dades. En un entorn proper a la Terra amb pocs dispositius i connectivitat fiable, això no suposa una limitació pel que poden ser operats manualment gairebé en temps real. No obstant, amb major nombre de satèl·lits i en enentorns de Delay Tolerant Network (DTN), on la connectivitat és inestable i interrompuda amb llargues demores, cal confiar en l'automatització. En aquest aspecte, ja s'han realitzat estudis utilitzant el Reinforcement Learning per gestionar la memòria d'un node DTN amb resultats prometedors. Tot i així, aquests mètodes requereixen de molt temps de simulació i no són aptes per a ser implementats en els ordinadors de a bord. Es podria entendre, però, com un agent de control centralitzat amb resultats i xarxes neuronals delegades als satèl·lits. En aquest projecte, es presenta un enfocament més lleuger utilitzant Teoria de Control Clàssica modelant el node DTN com un sistema de cues on la taxa de transmissió s'ajusta automàticament per mantenir un estat concret de la memòria. En aquest aspecte, ja s'han realitzat estudis utilitzant el Reinforcement Learning per gestionar la memòria d'un node DTN amb resultats prometedors. No obstant això, aquests mètodes requereixen de molt temps de simulació i no són aptes per a ser implementats en els ordinadors de a bord. Es podrien entendre, però, com un agent de control centralitzat amb resultats i xarxes neuronals delegades als satèl·lits. En aquest projecte, es presenta un enfocament més lleuger utilitzant Teoria de Control Clàssica modelant el node DTN com un sistema de cues on la taxa de transmissió s'ajusta automàticament per mantenir un estat concret de la memòria.Los satélites carecen de un comportamiento autónomo con respecto a la adquisición y transmisión de datos. En un entorno cercano a la Tierra con pocos dispositivos y conectividad fiable, esto no supone una limitación por lo que pueden ser operados manualmente casi en tiempo real. Sin embargo, con mayor número de satélites en enentornos de Delay Tolerant Network (DTN), donde la conectividad es inestable e interrumpida con largas demoras, es necesario confiar en la automatización. En este aspecto, ya se han realizado estudios utilizando el Reinforcement Learning para gestionar la memoria de un nodo DTN con resultados prometedores. No obstante, estos métodos requieren de mucho tiempo de simulación y no son aptos para ser implementados en los ordenadores de a bordo. Se podrían entender, sin embargo, como un agente de control centralizado con resultados y redes neuronales delegadas a los satélites. En este proyecto, se presenta un enfoque más ligero utilizando Teoría de Control Clásica modelando el nodo DTN como un sistema de colas donde la tasa de transmisión se ajusta automáticamente para mantener un estado concreto de la memoria.Satellites lack autonomous behavior regarding data acquisition and transmission. In a near Earth environment with few spacecraft and reliable connectivity, this is not a limitation for which they can be almost real time and manually operated. However, in Delay/Disruption Tolerant Networks (DTN) environments where connectivity is unstable/disrupted with long delays and with greater number of spacecraft, it is necessary to rely on automation. Some approaches have already been made using Reinforcement Learning to manage DTN node buffers with promising results . However, this methods are highly computer intensive and are not suitable to be implemented in the on-board computers. They could, however, be understood as a centralized control agent with delegated results and Neural Net (NN) implementations. In this thesis, a lighter approach is presented using Classical Control Theory modeling the DTN node as a Queuing System using classical dynamics, where the transmission rate is autonomously adjusted to maintain a specific memory state

    Mejoras a introducir en la información de la Memoria del PGCPYMES español: sucursales con pérdidas.

    Get PDF
    En España, el incluir en la memoria del PGCPYMES, información sobre la evolución y el resultado económico de una sucursal que presenta pérdidas y descensos en las ventas, mientras que el resto de establecimientos y la propia cuenta de pérdidas y ganancias global de la empresa presenta beneficios, debería ser una decisión más que opcional, pues en la memoria se deberá indicar cualquier información necesaria para permitir el conocimiento de la situación y actividad de la empresa en el ejercicio, y completará, ampliará y comentará la información de los otros documentos que integran las cuentas anuales. In Spain, to include in the memory of the PGCPYMES, information about the evolution and the economic result of a branch that presents losses and decreases in the sales, whereas the rest of establishments and the own global account of losses and earnings of the company presents benefits, should be a decision more that optional, since in the memory it will have indicate any necessary information to allow the knowledge of the situation and activity of the company in the exercise, and it will complete, it will extend and comment on the information of other documents that integrate the annual accounts.PGC, Memoria, transparencia. PGC, Memory, transparency.

    Diagnosing Errors in DbC Programs Using Constraint Programming

    Get PDF
    Model-Based Diagnosis allows to determine why a correctly designed system does not work as it was expected. In this paper, we propose a methodology for software diagnosis which is based on the combination of Design by Contract, Model-Based Diagnosis and Constraint Programming. The contracts are specified by assertions embedded in the source code. These assertions and an abstraction of the source code are transformed into constraints, in order to obtain the model of the system. Afterwards, a goal function is created for detecting which assertions or source code statements are incorrect. The application of this methodology is automatic and is based on Constraint Programming techniques. The originality of this work stems from the transformation of contracts and source code into constraints, in order to determine which assertions and source code statements are not consistent with the specification.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0

    De Amo a Laura a The Wilderness Downtown. Una propuesta taxonómica para clasificar el audiovisual publicitario en Internet

    Get PDF
    Antecedentes. El escenario audiovisual ha sufrido, en los últimos años, una mutación sin precedentes gracias, entre otros factores, a la universalización de Internet y al cada vez mejor acceso a la banda ancha. Páginas web basadas en elementos audiovisuales y portales como YouTube, Vimeo o Google Video han revolucionado la forma en la que las piezas audiovisuales se distribuyen, pero también la forma en la se crean y, por supuesto, la forma en la que se consumen. Los vídeos domésticos conviven con los profesionales —de todos los campos— generando un mapa audiovisual muy complejo: es caótico y difícilmente clasificable. Objeto de estudio. La publicidad online no ha sido ajena a este contexto, integrando piezas audiovisuales en sus campañas para Internet, muy distintas desde el punto de vista estratégico, en forma y en contenido de las tradicionales piezas publicitarias para el que hasta ahora era el medio audiovisual publicitario por excelencia: la televisión. Objetivo. El objetivo de esta investigación es confeccionar una taxonomía válida para clasificar el audiovisual publicitario en Internet. Metodología. Partiendo de conceptos tradicionales (creación, producción, distribución, exhibición, resultados) y desarrollándolos atendiendo a las especificidades de los nuevos medios (Lister et al, 2009), se ha creado una taxonomía inicial que después ha sido testada clasificando las piezas audiovisuales de 80 campañas ganadoras en 2011 en la sección Cyber del Festival Internacional Cannes Lions.Background. The audiovisual scene has suffered in recent years, an unprecedented mutation because of the universalization of the Internet and an increasing access to broadband, among other factors. Websites based on visual elements and platforms like YouTube, Vimeo and Google Video have changed the way in which audiovisual productionsare distributed, but also how they are created and, of course, the way you watched. Amateur productions compete with professional ones, in every fields, generating a very complex visual map: its is chaotic and difficult to classify. Object of study. Online advertising has not been immune to this context, integrating audiovisual productions in campaigns for the Internet, which are very different from the strategic point of view, in form and content, to traditional advertising productions for television. Aim. The aimof this research is to produce a valid taxonomy for classifying audiovisual advertising on the Internet. Methodology. Based on traditional concepts (creations, production, distribution, exhibition, performance) and developed in response to the specificities of new media (Lister et al, 2009), we created a preliminary taxonomy that has been tested by classifying audiovisual pieces of 80 winning campaigns in 2011 in the section Cyber of the International Festival Cannes Lions
    corecore