177 research outputs found

    A Spatial Microsimulation Model for the Estimation of Heat Demand in Hamburg

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    Most spatial bottom up domestic heat models are based on an existing building stock data set, this can be the official digital cadastre (ALKIS in Germany), community based data sources (e.g: open-street) or collected data stored on a GIS system. On this paper we present an innovative method for the creation of spatial bottom up domestic heat models that do not need an existing building stock data-set as input. The advantage of this type of models are its transferability, speed and flexibility. The presented model uses national standardized statistical data, making it possible to apply it for any region in the country without having to modify the model. Because the input data for the model is more compact the speed of the model increases significantly, the type of analysis possible with a high speed model allow us to perform a microsimulation of the building stock for the entire country, see (Muñoz H., Seller, & Peters, 2015). The presented model structure allows us to quickly develop dynamic simulation scenarios. We present a spatial microsimulation model developed for the simulation of domestic heat demand. The presented model use the GREGWT R package to create a synthetic building stock benchmarked to aggregated small area statistics from the 2011 German census. We create this synthetic building stock from the 2010 microsensus. The heat estimation if performed on the microcensus with help of the heat R package. The simulation results present a monthly heat demand at a microlevel for the entire city of Hamburg. The generated data for the estimation of heat demand can be use as input data for other Agent Based Models. By enriching the microcensus with time use data, we are able to generate the basis data for the construction of activity based urban models. We see the development of this type of urban models as an essential development of urban planning, specially for a smart urban development. The generation of microdata is a fundamental part of the smart city development

    Enriching the 3D City-Model for the Simulation of Urban Heat Demand

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    In this paper we describe the process of enriching the Hamburg 3D City model (3D-Stadtmodell) with energy relevant attributes for the simulation of heat demand. The 3D data of the city provided by the Landesbetrieb Geoinformation und Vermessung (LGV) is a combination of Cadastre footprints and LiDAR data. This combination of data allows the LGV to produce CityGML data with a level of detail 1 (LOD1). We use this data as basis for the computation of urban heat demand. This paper presents the enrichment process of the CityGML data. We make use of the energy application domain extension (ADE) to store the energy relevant data in a standardized format. For the enrichment process we classify the residential building stock into building types. And classify the non residential sector by use. From the building types we extract heat transmission coefficients of building components. With the enriched 3D city model we perform a monthly heat demand estimation of a selected neighbourhood in Hamburg. The aim of this enrichment process is to create a robust but flexible method for the estimation of heat demand at a neighbourhood level with little energy relevant information. This paper presents a method for a quick estimation of the monthly heat demand of a neighbourhood without the need of any extra data input. This approach can be used by the energy and urban planning community for a first estimation of the heat demand used on a given neighbourhood or the entire city. The results from this approach present an urban heat demand model for the city of Hamburg based on the freely available 3D city model data. Possible uses of this approach are: (1) identification of hot spots in the city, (2) creation of base data sets for the simulation of retrofit scenarios, and (3) creation of temporal heat density maps

    Numerical schemes for continuum models of reaction-diffusion systems subject to internal noise

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    We present new numerical schemes to integrate stochastic partial differential equations which describe the spatio-temporal dynamics of reaction-diffusion (RD) problems under the effect of internal fluctuations. The schemes conserve the nonnegativity of the solutions and incorporate the Poissonian nature of internal fluctuations at small densities, their performance being limited by the level of approximation of density fluctuations at small scales. We apply the new schemes to two different aspects of the Reggeon model namely, the study of its non-equilibrium phase transition and the dynamics of fluctuating pulled fronts. In the latter case, our approach allows to reproduce quantitatively for the first time microscopic properties within the continuum model.Comment: 5 pages, 3 figures, Accepted for publication in Physical Review E as a Rapid Communicatio

    Radio detections towards unidentified variable EGRET sources

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    Context. A considerable fraction of the -ray sources discovered with the Energetic Gamma-Ray Experiment Telescope (EGRET) remain unidentified. The EGRET sources that have been properly identified are either pulsars or variable sources at both radio and gamma-ray wavelengths. Most of the variable sources are strong radio blazars. However, some low galactic-latitude EGRET sources, with highly variable -ray emission, lack any evident counterpart according to the radio data available until now. Aims. The primary goal of this paper is to identify and characterise the potential radio counterparts of four highly variable -ray sources in the galactic plane through mapping the radio surroundings of the EGRET confidence contours and determining the variable radio sources in the field whenever possible. Methods. We have carried out a radio exploration of the fields of the selected EGRET sources using the Giant Metrewave Radio Telescope (GMRT) interferometer at 21 cm wavelength, with pointings being separated by months. Results. We detected a total of 151 radio sources. Among them, we identified a few radio sources whose flux density has apparently changed on timescales of months. Despite the limitations of our search, their possible variability makes these objects a top-priority target for multiwavelength studies of the potential counterparts of highly variable, unidentified gamma-ray sources.Facultad de Ciencias AstronĂłmicas y GeofĂ­sicasInstituto Argentino de RadioastronomĂ­

    Radio continuum and near-infrared study of the MGRO J2019+37 region

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    Context.MGRO J2019+37 is an unidentified extended source of very high energy gamma-rays originally reported by the Milagro Collaboration as the brightest TeV source in the Cygnus region. Its extended emission could be powered by either a single or several sources. The GeV pulsar AGL J2020.5+3653, discovered by AGILE and associated with PSR J2021+3651, could contribute to the emission from MGRO J2019+37. Aims. Our aim is to identify radio and near-infrared sources in the field of the extended TeV source MGRO J2019+37, and study potential counterparts to explain its emission. Methods. We surveyed a region of about 6 square degrees with the Giant Metrewave Radio Telescope (GMRT) at the frequency 610 MHz. We also observed the central square degree of this survey in the near-infrared Ks-band using the 3.5 m telescope in Calar Alto. Archival X-ray observations of some specific fields are included. VLBI observations of an interesting radio source were performed. We explored possible scenarios to produce the multi-TeV emission from MGRO J2019+37 and studied which of the sources could be the main particle accelerator. Results. We present a catalogue of 362 radio sources detected with the GMRT in the field of MGRO J2019+37, and the results of a cross-correlation of this catalog with one obtained at near-infrared wavelengths, which contains ∌3 × 105 sources, as well as with available X-ray observations of the region. Some peculiar sources inside the ∌1° uncertainty region of the TeV emission from MGRO J2019+37 are discussed in detail, including the pulsar PSR J2021+3651 and its pulsar wind nebula PWN G75.2+0.1, two new radio-jet sources, the Hii region Sh 2-104 containing two star clusters, and the radio source NVSS J202032+363158. We also find that the hadronic scenario is the most likely in case of a single accelerator, and discuss the possible contribution from the sources mentioned above. Conclusions. Although the radio and GeV pulsar PSR J2021+3651 / AGL J2020.5+3653 and its associated pulsar wind nebula PWN G75.2+0.1 can contribute to the emission from MGRO J2019+37, extrapolation of the GeV spectrum does not explain the detected multi-TeV flux. Other sources discussed here could contribute to the emission of the Milagro source.Instituto Argentino de RadioastronomĂ­aFacultad de Ciencias AstronĂłmicas y GeofĂ­sica

    Low-frequency radio observations of the MGRO J2019+37 Complex

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    We present here a preliminary account of the results of a wide-field mosaic obtained at 610 MHz (49 cm) with the Giant Metre-wave Radio Telescope (GMRT) in India covering the field of the unidentified TeV source MGRO J2019+37. A catalogue of all radio sources detected has been created including both compact and extended objects. Their observational properties are described and presented. We draw the attention to some peculiar objects inside the ˜1° uncertainty region of the TeV emission. The possible connection of these sources with the MILAGRO Îł-ray emission will be assessed in future work.Fil: SĂĄnchez Sutil, Juan R. . Universidad de JaĂ©n; EspañaFil: Paredes, Josep M.. Universitat de Barcelona. Departament d’Astronomia i Meteorologia and Institut de CiĂšncies del Cosmos; EspañaFil: MoldĂłn, J.. Universitat de Barcelona. Departament d’Astronomia i Meteorologia and Institut de CiĂšncies del Cosmos; EspañaFil: Zabalza, V.. Universitat de Barcelona. Departament d’Astronomia i Meteorologia and Institut de CiĂšncies del Cosmos; EspañaFil: Bordas, P.. Universitat de Barcelona. Departament d’Astronomia i Meteorologia and Institut de CiĂšncies del Cosmos; EspañaFil: RibĂł, M.. Universitat de Barcelona. Departament d’Astronomia i Meteorologia and Institut de CiĂšncies del Cosmos; EspañaFil: MartĂ­, Josep. Universidad de JaĂ©n; EspañaFil: Muñoz Arjonilla, Alvaro J.. Universidad de JaĂ©n; EspañaFil: Luque Escamilla, Pedro L.. Universidad de JaĂ©n; EspañaFil: Ishwara Chandra, C. H.. NCRA. TIFR; IndiaFil: Peracaula, Marta. Universidad de Girona; EspañaFil: Bosch Ramon, Valenti. Max Planck Institut Fur Kernphysik, Heidelberg; AlemaniaFil: Romero, Gustavo Esteban. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico La Plata. Instituto Argentino de Radioastronomia (i); Argentin

    Network structure of avian mixed-species flocks decays with elevation and latitude across the Andes.

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    Birds in mixed-species flocks benefit from greater foraging efficiency and reduced predation, but also face costs related to competition and activity matching. Because this cost-benefit trade-off is context-dependent (e.g. abiotic conditions and habitat quality), the structure of flocks is expected to vary along elevational, latitudinal and disturbance gradients. Specifically, we predicted that the connectivity and cohesion of flocking networks would (i) decline towards tropical latitudes and lower elevations, where competition and activity matching costs are higher, and (ii) increase with lower forest cover and greater human disturbance. We analysed the structure of 84 flock networks across the Andes and assessed the effect of elevation, latitude, forest cover and human disturbance on network characteristics. We found that Andean flocks are overall open-membership systems (unstructured), though the extent of network structure varied across gradients. Elevation was the main predictor of structure, with more connected and less modular flocks upslope. As expected, flocks in areas with higher forest cover were less cohesive, with better defined flock subtypes. Flocks also varied across latitude and disturbance gradients as predicted, but effect sizes were small. Our findings indicate that the unstructured nature of Andean flocks might arise as a strategy to cope with harsh environmental conditions. This article is part of the theme issue 'Mixed-species groups and aggregations: shaping ecological and behavioural patterns and processes'

    Radio detections towards unidentified variable EGRET sources

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    Context. A considerable fraction of the -ray sources discovered with the Energetic Gamma-Ray Experiment Telescope (EGRET) remain unidentified. The EGRET sources that have been properly identified are either pulsars or variable sources at both radio and gamma-ray wavelengths. Most of the variable sources are strong radio blazars. However, some low galactic-latitude EGRET sources, with highly variable -ray emission, lack any evident counterpart according to the radio data available until now. Aims. The primary goal of this paper is to identify and characterise the potential radio counterparts of four highly variable -ray sources in the galactic plane through mapping the radio surroundings of the EGRET confidence contours and determining the variable radio sources in the field whenever possible. Methods. We have carried out a radio exploration of the fields of the selected EGRET sources using the Giant Metrewave Radio Telescope (GMRT) interferometer at 21 cm wavelength, with pointings being separated by months. Results. We detected a total of 151 radio sources. Among them, we identified a few radio sources whose flux density has apparently changed on timescales of months. Despite the limitations of our search, their possible variability makes these objects a top-priority target for multiwavelength studies of the potential counterparts of highly variable, unidentified gamma-ray sources.Facultad de Ciencias AstronĂłmicas y GeofĂ­sicasInstituto Argentino de RadioastronomĂ­

    Radio continuum and near-infrared study of the MGRO J2019+37 region

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    Context.MGRO J2019+37 is an unidentified extended source of very high energy gamma-rays originally reported by the Milagro Collaboration as the brightest TeV source in the Cygnus region. Its extended emission could be powered by either a single or several sources. The GeV pulsar AGL J2020.5+3653, discovered by AGILE and associated with PSR J2021+3651, could contribute to the emission from MGRO J2019+37. Aims. Our aim is to identify radio and near-infrared sources in the field of the extended TeV source MGRO J2019+37, and study potential counterparts to explain its emission. Methods. We surveyed a region of about 6 square degrees with the Giant Metrewave Radio Telescope (GMRT) at the frequency 610 MHz. We also observed the central square degree of this survey in the near-infrared Ks-band using the 3.5 m telescope in Calar Alto. Archival X-ray observations of some specific fields are included. VLBI observations of an interesting radio source were performed. We explored possible scenarios to produce the multi-TeV emission from MGRO J2019+37 and studied which of the sources could be the main particle accelerator. Results. We present a catalogue of 362 radio sources detected with the GMRT in the field of MGRO J2019+37, and the results of a cross-correlation of this catalog with one obtained at near-infrared wavelengths, which contains ∌3 × 105 sources, as well as with available X-ray observations of the region. Some peculiar sources inside the ∌1° uncertainty region of the TeV emission from MGRO J2019+37 are discussed in detail, including the pulsar PSR J2021+3651 and its pulsar wind nebula PWN G75.2+0.1, two new radio-jet sources, the Hii region Sh 2-104 containing two star clusters, and the radio source NVSS J202032+363158. We also find that the hadronic scenario is the most likely in case of a single accelerator, and discuss the possible contribution from the sources mentioned above. Conclusions. Although the radio and GeV pulsar PSR J2021+3651 / AGL J2020.5+3653 and its associated pulsar wind nebula PWN G75.2+0.1 can contribute to the emission from MGRO J2019+37, extrapolation of the GeV spectrum does not explain the detected multi-TeV flux. Other sources discussed here could contribute to the emission of the Milagro source.Instituto Argentino de RadioastronomĂ­aFacultad de Ciencias AstronĂłmicas y GeofĂ­sica

    Planeamiento territorial sostenible: un reto para el futuro de nuestras sociedades; criterios aplicados

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    In a large part of the 17 sustainable development objectives set as goals for humanity by the UN, sustainability can be glimpsed. As a result of the dominant socio-productive model, the only way to head towards more sustainable territories that allow achieving and maintaining the well-being of the world's population is to bear in mind the need to properly plan territorial development. This work reflects on this need and takes a step forward in the definition of the main criteria to achieve territorial sustainability at regional and local scales
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