610 research outputs found

    Power Quality Monitoring Integration into Distribution Automation through the Use of AMR

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    Power-quality events are of increasing concern for the economy because today’s equipment, particularly computers and automated manufacturing devices, is highly sensitive to such imperfections. With volatile energy rates and a need to control costs, regional agencies and utilities are interested in technologies to meter distribution use and manage utility information. Metering technologies and communications systems have advanced to enable the development of Automated Meter Reading (AMR) Systems. Power Quality is one area where the AMR system can be very valuable. This paper investigates the challenges in the development of distributed power-quality monitoring system. The approach of this paper is divided into metering, data collection, archiving, analysis, and presentation. It also discusses system architecture, implementation, and provides general guidelines in the tailoring of PQ indexes. This paper describes the challenges and lessons learned from this work.

    DIFFERENTIAL TEMPORAL AND SPATIAL DISTRIBUTION OF ADULT LOGGERHEAD SEA TURTLES FROM GULF OF CÁDIZ TO WESTERN MEDITERRANEAN SEA

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    The aim of this paper was to search for and model spatial and seasonal trends in occurrences (stranding or by-catches) of adult loggerhead turtles in the western Mediterranean area and Gulf of Cádiz (Atlantic) independently of their origin. Adult turtles were only bycaught on longlines from May to August. Adults were stranded in the eastern and western areas of the Strait of Gibraltar threshold throughout the year. In the Gulf of Cádiz (Atlantic), strandings were significantly concentrated in May and June, whereas in the Alboran Sea (Mediterranean), strandings mainly occurred in June and July. The probability of catching a mature loggerhead increases during June and July south of the Balearic Islands. The results suggest that adult loggerhead turtles move (migrate) from the Atlantic area (Gulf of Cádiz) to the Mediterranean (Alboran Sea) from May to June, and subsequently move to the Balearic Sea from June to July. These results are in line with those obtained by previous studies.Postprin

    Aprendizaje interdisciplinar de la electrónica y las comunicaciones

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    En este proyecto de innovación docente se pretende profundizar en el conocimiento de la base teórica, la construcción de los modelos matemáticos físicos que son la base de los diseños electrónicos, mediante el montaje, presentación, simulación y experimentación. El procedimiento se basa en la realización de medidas experimentales básicas a principio de curso y en las aplicaciones interdisciplinares a final de curso, así como disponer de todo el material vía Internet para motivar el aprendizaje del alumno.The aim of this teaching innovation project is to look for deeply into knowledge about the theoretical base and construction of mathematical models that are the basis of electrical design, making use of setups, lectures, simulations and experimentations. The procedure is based upon the execution of essential experimental measurements at the beginning of the school year and on interdisciplinary applications at the end of it, all complemented with related Internet resources targeted to improve student motivation

    Integrating local environmental data and information from non-driven citizen science to estimate jellyfish abundance in Costa del Sol (southern Spain)

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    Tourism, fishing and aquaculture are key economic sectors of Costa del Sol (southern Iberian Peninsula). The management of these activities is sometimes disturbed by the onshore arrival and stranding of jellyfish swarms. In the absence data on the occurrence of these organisms, it may be interesting to explore data from non-driven systems, such as social networks. The present study show how data in text format from a mobile app called Infomedusa can be processed and used to model the relationship between estimated abundance of jellyfish on the beaches and local environmental conditions. The data retrieved from this app using artificial intelligence procedures (transition network or TN algorithm), were used as input for GAM models to estimate the abundance of jellyfish based on wind speed and direction. The analysis of data provided by Infomedusa indicated that only 30.39% of messages provided by the users had information about absence/presence of jellyfishes in the beaches. On the other hand, the TN processing capacity showed an accuracy level to discriminate messages with information on absence/presence of jellyfish slightly higher than 80%. GAM models considering the wind direction and speed of previous day explained between 37% and 77% of the variance of jellyfish abundance estimate from Infomedusa data. In conclusion, this approach may contribute to the development of a system for predicting the onshore arrival of jellyfish in the Costa del Sol.Versión del edito

    Quantum Creation of an Open Inflationary Universe

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    We discuss a dramatic difference between the description of the quantum creation of an open universe using the Hartle-Hawking wave function and the tunneling wave function. Recently Hawking and Turok have found that the Hartle-Hawking wave function leads to a universe with Omega = 0.01, which is much smaller that the observed value of Omega > 0.3. Galaxies in such a universe would be about 1010810^{10^8} light years away from each other, so the universe would be practically structureless. We will argue that the Hartle-Hawking wave function does not describe the probability of the universe creation. If one uses the tunneling wave function for the description of creation of the universe, then in most inflationary models the universe should have Omega = 1, which agrees with the standard expectation that inflation makes the universe flat. The same result can be obtained in the theory of a self-reproducing inflationary universe, independently of the issue of initial conditions. However, there exist two classes of models where Omega may take any value, from Omega > 1 to Omega << 1.Comment: 23 pages, 4 figures. New materials are added. In particular, we show that boundary terms do not help to solve the problem of unacceptably small Omega in the new model proposed by Hawking and Turok in hep-th/9803156. A possibility to solve the cosmological constant problem in this model using the tunneling wave function is discusse

    Inflation with improved D3-brane potential and the fine tunings associated with the model

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    We investigate brane-antibrane inflation in a warped deformed conifold background that includes contributions to the potential arising from imaginary anti-self-dual (IASD) fluxes including the term with irrational scaling dimension discovered recently. We find that the model can give rise to required number of e-foldings; observational constraint on COBE normalization is easily satisfied and low value of the tensor to scalar ratio of perturbations is achieved. We observe that these corrections to the effective potential help in relaxing the severe fine tunings associated with the earlier analysis.Comment: 8 pages, 4 figures; typos corrected, minor clarifications and new refs added, to appear in epj

    Análisis temporal de varamientos de tortuga laúd, Dermochelys

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    Leatherback sea turtle (Dermochelys coriacea, Vandelli, 1761)) is a large migratory species reproducing in Atlantic areas and abundant in the Mediterranean Sea, where nesting beaches do not exist. Leatherback stranding occasionally occurs in the Andalusia coasts (183 turtles during 1990- 2011 period). This communication study a possible inter and intra annual temporal patterns in leatherback strandings in the area and analyze the effects of atmospheric oscillations on their arrivals in the Mediterranean. The North Atlantic Oscillation (NAO) plays an essential role in climate fluctuations affecting the North Atlantic and associated biological components. Recent studies showed that the Arctic Oscillation (AO) is highly correlated with NAO, explaining more accurately variations found in ecological time series. The summer months concentrate significatively a higher number of leatherback turtle strandings. Moreover, the results show a significant negative correlation between the stranding frequency and the average rate of the AO.Postprin

    Evidencias arqueológicas de desplomes paramentales traumáticos en las Termas Marítimas de Baelo Claudia. Reflexiones arqueosismológicas

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    Durante los años 2011 a 2013 se han localizado, identificado y excavado parcialmente los restos de un nuevo complejo termal en la ciudad hispanorromana de Baelo Claudia (Tarifa, Cádiz), situado en el suburbium occidental de la ciudad, junto a la línea de costa. Denominadas Termas Marítimas, construidas en la primera mitad del s. II d.C. y abandonadas en época de Diocleciano/Constantino han sido excavadas estratigráficamente con detalle, habiéndose detectado la existencia de fases anteriores (que se remontan al s. II a.C.) y una continuidad de uso del ambiente en época tardorromana y moderna, vinculada con la explotación de los recursos marinos. Especialmente singular ha sido la constatación del desplome traumático de parte de los paramentos de las habitaciones del edificio en dos momentos concretos: por un lado en la Antigüedad Tardía (500 d.C. circa), ya que una unidad muraria de una de las habitaciones (H-3), anexa a la natatio, se localizó completamente derrumbada sobre el suelo, conexionada; y por otro, el desplome del muro oeste de la natatio y el oriental de la cisterna, estructuras de más de seis metros de longitud y cuatro de altura mínima conservada, desplomadas sobre los niveles de abandono del asentamiento en época bajomedieval o moderna (ss. XIV-XV d.C.). Se trata en ambas ocasiones de colapsos estructurales no habituales en circunstancias normales en los procesos de sedimentación arqueológica, por lo que es muy probable que su desplome se pueda vincular con eventos sísmicos u otras causas naturales similare

    Uplifting and Inflation with D3 Branes

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    Back-reaction effects can modify the dynamics of mobile D3 branes moving within type IIB vacua, in a way which has recently become calculable. We identify some of the ways these effects can alter inflationary scenarios, with the following three results: (1) By examining how the forces on the brane due to moduli-stabilizing interactions modify the angular motion of D3 branes moving in Klebanov-Strassler type throats, we show how previous slow-roll analyses can remain unchanged for some brane trajectories, while being modified for other trajectories. These forces cause the D3 brane to sink to the bottom of the throat except in a narrow region close to the D7 brane, and do not ameliorate the \eta-problem of slow roll inflation in these throats; (2) We argue that a recently-proposed back-reaction on the dilaton field can be used to provide an alternative way of uplifting these compactifications to Minkowski or De Sitter vacua, without the need for a supersymmetry-breaking anti-D3 brane; and (3) by including also the D-term forces which arise when supersymmetry-breaking fluxes are included on D7 branes we identify the 4D supergravity interactions which capture the dynamics of D3 motion in D3/D7 inflationary scenarios. The form of these potentials sheds some light on recent discussions of how symmetries constrain D term interactions in the low-energy theory.Comment: JHEP.cls, 35 pages, 3 .eps figure

    SUSY Quivers, Intersecting Branes and the Modest Hierarchy Problem

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    We present a class of chiral non-supersymmetric D=4 field theories in which quadratic divergences appear only at two loops. They may be depicted as ``SUSY quivers'' in which the nodes represent a gauge group with extended e.g., N=4 SUSY whereas links represent bifundamental matter fields which transform as chiral multiplets with respect to different N=1 subgroups. One can obtain this type of field theories from simple D6-brane configurations on Type IIA string theory compactified on a six-torus. We discuss the conditions under which this kind of structure is obtained from D6-brane intersections. We also discuss some aspects of the effective low-energy field theory. In particular we compute gauge couplings and Fayet-Iliopoulos terms from the Born-Infeld action and show how they match the field theory results. This class of theories may be of phenomenological interest in order to understand the modest hierarchy problem i.e., the stability of the hierarchy between the weak scale and a fundamental scale of order 10-100 TeV which appears e.g. in low string scale models. Specific D-brane models with the spectrum of the SUSY Standard Model and three generations are presented.Comment: 36 pages, using JHEP3.cls, 8 figures. References update
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