6,501 research outputs found

    Towards Parameterized Regular Type Inference Using Set Constraints

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    We propose a method for inferring \emph{parameterized regular types} for logic programs as solutions for systems of constraints over sets of finite ground Herbrand terms (set constraint systems). Such parameterized regular types generalize \emph{parametric} regular types by extending the scope of the parameters in the type definitions so that such parameters can relate the types of different predicates. We propose a number of enhancements to the procedure for solving the constraint systems that improve the precision of the type descriptions inferred. The resulting algorithm, together with a procedure to establish a set constraint system from a logic program, yields a program analysis that infers tighter safe approximations of the success types of the program than previous comparable work, offering a new and useful efficiency vs. precision trade-off. This is supported by experimental results, which show the feasibility of our analysis

    A multiplexing architecture for mixed-signal CMOS fuzzy controllers

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    Limits to precision impose limits to the complexity of analog circuits, hence fuzzy analog controllers are usually oriented to fast low-power systems with low-medium complexity. This paper presents a strategy to preserve most of the advantages of an analog implementation, while allowing a marked increment in system complexity.The works in this papaer has been partially funded by the spanish C.I.C.Y.T. under contract TIC96-1392-C02-02 (SIVA

    Australian Asian options

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    We study European options on the ratio of the stock price to its average and viceversa. Some of these options are traded in the Australian Stock Exchange since 1992, thus we call them Australian Asian options. For geometric averages, we obtain closed-form expressions for option prices. For arithmetic means, we use dierent approximations that produce very similar results.Asian options, arithmetic average, geometric average, edgeworth expansion, lognormal distribution, gamma distribution

    Volterra Model Based Predictive Control, application to a Pem Fue Cell

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    14th Nordic Process Control Workshop - Espoo, Finland Duration: 23 Aug 2007 → 25 Aug 2007This paper presents a non linear model predictive controller for a PEM fuel cell for which the starvation control is the main objective. A second order Volterra model for control is obtained using input/output data for which the power supplied by the fuel cell is considered as a measurable disturbance. The controller developed allows to solve the nonlinear objective function in a way that it can be actually implemented in fast systems like Fuel cells. The use of a nonlinear controller is justified while comparing the outcome obtained with a linear controller of the same class

    Danzas Espanolas

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    https://digitalcommons.library.umaine.edu/mmb-ps/3531/thumbnail.jp

    Aplicabilidad de las TIG en la generación de escenarios de futuro para una gestión integrada de las zonas costeras

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    Para una planificación y gestión coherente de las zonas costeras es fundamental que exista una profunda comprensión de las interacciones entre el hombre y el medio físico, siendo preciso integrar la información sobre el conocimiento del medio natural aportada por las diferentes disciplinas científicas, junto con la información del contexto socio-económico, normativo y cultural. Por tanto, la toma de decisiones en los espacios litorales debe apoyarse en instrumentos interdisciplinares, capaces de operar con distintos tipos de datos y abordar situaciones complejas e impredecibles. La simulación de escenarios es una importante herramienta para evaluar desarrollos futuros en sistemas complejos y dinámicos que poseen un número alto de incertidumbres, y por ello es una técnica muy adecuada para la gestión de las zonas costeras. Los escenarios permiten integrar modelos socioeconómicos con modelos físicos, químicos o biológicos, reflejar una amplia gama de tendencias y dinámicas, y trabajar con distintas escalas temporales y espaciales. En el presente artículo se examina el uso actual y el potencial de las TIG en la generación de escenarios de futuro para la gestión integrada de las zonas costeras. Para ello se ha realizado un análisis de su aplicabilidad de las TIG, identificando en qué fases de la elaboración de escenarios se pueden utilizar. Los resultados indican que estas tecnologías tienen un alto potencial y son aplicables en todas las fases de la generación de los escenarios. Una de las fortalezas identificadas es que las TIG incrementan la transparencia y fiabilidad de la generación de escenarios de futuro facilitando los procesos equitativos y participativos de negociación, toma de decisiones y planificación en las zonas costeras.To achieve a coherent planning and management of coastal areas it is necessary having a deep understanding of the interactions existing between human-being and the physical environment, integrating information from different scientific disciplines (hydrology, morphodynamics, soil science, ecology, etc.) and socio-economic, normative and cultural context information. Therefore decision-making in coastal areas must be based on interdisciplinaryinstruments capable of working with different type of data and dealing with complex and unpredictable situations. Scenario-making is one of the most important tools for assessing future developments in complex and dynamic systems which have a high number of uncertainties; thus it is a very suitable approach for coastal zone management. Scenarios can integrate socio-economic models with physical, chemical or biological models, reflect a broad range of trends and dynamics, and work with different temporal and spatial scales. In this paper the current and potential use of Geographical Information Technologies (GIT) is examined in the generation of future scenarios for an integrated management of coastal areas. An analysis of the applicability of the GIT has been done, identifying at which stage of scenario development GIT can be used. The results indicate that GIT have great potential and are applicable at all stages of the scenarios generation. One of the strengths identified is that GIT increase the transparency and reliability of the generation of future scenarios and facilitate equitable and participatory processes of negotiation, decision making and planning in coastal areas

    Spreading the use of economic methods in coastal risk management: a simple but insightful “calculator”

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    Navas, F.; Malvárez, G.; Penning-Rowsell, E., and Parker, D.J., 2020. Spreading the use of economic methods in coastal risk management: A simple but insightful "calculator". In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1217–1222. Coconut Creek (Florida), ISSN 0749-0208. European Directives, such as the EU Floods Directive (2007/60/EC) require that decision makers include objective methodologies, such as benefit-cost analysis, in their assessments of flood risk reduction measures. Methodologies to establish a sustainable knowledge framework addressing the costs and benefits of prevention and response to coastal hazards resulting from hydro-meteorological, hydrographic and other natural events and processes (e.g. flooding, beach erosion, cliff erosion, sea level rise) are not homogeneously implemented in the European Union. Until now, investment decisions in this field have been made more on local political imperatives than logical economic risk assessments. This paper aims to overcome some these limitations by demonstrating the usefulness of a simplified benefit-cost methodology and its application to a coastal case where a number of alternative flood risk reduction schemes are considered. The method allows the economically optimal scheme to be identified. The method is discussed within the context of generally poorly comprehended aspects; issues presented in coupling benefit-cost methods with vulnerability and related assessments; and key data uncertainties

    An integrated approach toward the incorporation of clouds in the temperature retrievals from microwave measurements

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    In this paper, we address the characterization of clouds and its inclusion in microwave retrievals in order to study its effect on tropospheric temperature profiles measured by TEMPERA radiometer. TEMPERA is the first ground-based microwave radiometer that makes it possible to obtain temperature profiles in the troposphere and stratosphere at the same time. In order to characterize the clouds a multi-instrumental approach has been adopted. Cloud base altitudes were detected using ceilometer measurements while the integrated liquid water was measured by TROWARA radiometer. Both instruments are co-located with TEMPERA in Bern (Switzerland). Using this information and a constant Liquid Water Content value inside the cloud a liquid profile is provided to characterize the clouds in the inversion algorithm. Microwave temperature profiles have been obtained incorporating this water liquid profile in the inversion algorithm and also without considering the clouds, in order to assess its effect on the retrievals. The results have been compared with the temperature profiles from radiosondes which are launched twice a day at the aerological station of MeteoSwiss in Payerne (40 km W of Bern). Almost 1 year of data have been analysed and 60 non-precipitating cloud cases were studied. The statistical analysis carried out over all the cases evidenced that temperature retrievals improved in most of the cases when clouds were incorporated in the inversion algorithm
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