64 research outputs found

    2nd edition of instrumenting smart city applications with big sensing and earth observatory data: Tools, methods and techniques

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    In lieu of an abstract, this is an excerpt from the first page. The exponential growth in the volume of Earth observation data and the increasing quality and availability of high-resolution imagery are increasingly making more applications possible in urban environments. In particular, remote sensing information, especially when combined with location-specific data collected locally or through connected devices, presents exciting opportunities for smart city applications, such as risk analysis and mitigation, climate prediction, and remote surveillance. On the other hand, the exploitation of this great amount of data poses new challenges for big data analysis models and requires new spatial information frameworks capable of integrating imagery, sensor observations, and social media in geographic information systems (GIS)

    Mobile data acquisition and processing in support of an urban heat island study

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    Global warming and changes in Earth’s weather patterns are the main consequences of climate change, and bioclimate discomfort has significant public health problems, especially for the elderly. Normally, the thermal characteristics of urban areas are poor due to a phenomenon known as urban heat island. Mobile and fixed temperature measurements were performed on 19 March 2021 in the city of Bologna, Italy. Mobile measurements took place with a car, along a 75-km transect, starting at 22:16 with a duration of 2 hours and 41 minutes, while fixed measurements were done using 15 present weather stations and also placing five thermometers in the city center. Various interpolation models (i.e., Traditional, Voronoi Tessellation, Global Trends, Triangulated Irregular Networks, Inverse Distance Weighting and Kriging) were applied to correct the mobile measurements using fixed data. Kriging fulfilled the best result with a correlation coefficient of 0.99 compared to the raw temperatures

    MONITORING THE URBAN GROWTH OF DHAKA (BANGLADESH) BY SATELLITE IMAGERY IN FLOODING RISK MANAGEMENT PERSPECTIVE

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    There is large consensus that demographic changes, the lack of appropriate environmental policies and sprawling urbanization result in high vulnerability and exposure to the natural disasters. This work reports some experiences of using multispectral satellite imagery to produce landuse/cover maps for the Dhaka city, the capital of Bangladesh, which is subject to frequent flooding events.The activity was conducted in collaboration with the non-profit organization ITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action). The Landsat images acquired in 2000, 2002 and 2009 were used to evaluate the urban growth in order to support risk assessment studies; to identify areas routinely flooded during the monsoon season, the image of October 2009 (the most critical month for the effects of rain) was compared with two images acquired in January and February 2010. The analysis between 2000 and 2009 was able to quantify a very rapid growth of the metropolis, with an increase in built-up areas from 75 to 111 km2. The analysis highlights also a sharp rise of Bare soil class, likely related to the construction of embankments for the creation of new building space; consequently a decrease of cultivated land was observed. In particular, these artificial islands have been invading flooding areas. The change detection procedure also showed that the flooding in October 2009 affected about 20% (115 out of 591 km2) of the entire study area; furthermore these areas became wetlands and farmland over the next three/four months

    Quantitative GIS-based analysis of archaeological data of the archaic state of Tell Mardikh/Ebla (3rdmillennium BC): The Big-DEA project

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    The paper provides an overview on Big-DEA, a multidisciplinary project aimed at developing a comprehensive multi-level explanatory model for the development of an archaic State in the ancient Near East, using the exceptional case of Tell Mardikh, ancient Ebla (Syria), during the second half of the 3rd millennium. The project's goal is the reconstruction of the archaic state organization through an integrated analysis of archaeological and epigraphic data. The interaction between humanities and hard sciences is adopted in order to build a multi-tier explanatory model regarding the territory under the control of the Ebla kingdom, considering anthropic and environmental data deriving from excavations, survey and textual sources. The way to managing and study such a large Big Data archive, which includes different datasets, is itself the main challenge of the project: the creation of a dedicated relational database management system (RDBMS) functional to the implementation of the available GIS platform and the development of an appropriate simulation framework

    Gravity in quantum spacetime

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    The literature on quantum-gravity-inspired scenarios for the quantization of spacetime has so far focused on particle-physics-like studies. This is partly justified by the present limitations of our understanding of quantum-gravity theories, but we here argue that valuable insight can be gained through semi-heuristic analyses of the implications for gravitational phenomena of some results obtained in the quantum-spacetime literature. In particular, we show that the types of description of particle propagation that emerged in certain quantum-spacetime frameworks have striking implications for gravitational collapse and for the behaviour of gravity at large distances.Comment: This essay received honorable mention in the Gravity Research Foundation 2010 Awards for Essays on Gravitatio

    Cornwall-Jackiw-Tomboulis effective potential for canonical noncommutative field theories

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    We apply the Cornwall-Jackiw-Tomboulis (CJT) formalism to the scalar λϕ4\lambda \phi^{4} theory in canonical-noncommutative spacetime. We construct the CJT effective potential and the gap equation for general values of the noncommutative parameter θμν\theta_{\mu\nu}. We observe that under the hypothesis of translational invariance, which is assumed in the effective potential construction, differently from the commutative case (θμν=0\theta_{\mu\nu}= 0), the renormalizability of the gap equation is incompatible with the renormalizability of the effective potential. We argue that our result, is consistent with previous studies suggesting that a uniform ordered phase would be inconsistent with the infrared structure of canonical noncommutative theories.Comment: 15 pages, LaTe

    On the IR/UV mixing and experimental limits on the parameters of canonical noncommutative spacetimes

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    We investigate some issues that are relevant for the derivation of experimental limits on the parameters of canonical noncommutative spacetimes. By analyzing a simple Wess-Zumino-type model in canonical noncommutative spacetime with soft supersymmetry breaking we explore the implications of ultraviolet supersymmetry on low-energy phenomenology. The fact that new physics in the ultraviolet can modify low-energy predictions affects significantly the derivation of limits on the noncommutativity parameters based on low-energy data. These are, in an appropriate sense here discussed, ``conditional limits''. We also find that some standard techniques for an effective low-energy description of theories with non-locality at short distance scales are only applicable in a regime where theories in canonical noncommutative spacetime lack any predictivity, because of the strong sensitivity to unknown UV physics. It appears useful to combine high-energy data, from astrophysics, with the more readily available low-energy data.Comment: 14 page

    Interpretation of neutrino oscillations based on new physics in the infrared

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    An interpretation of neutrino oscillations based on a modification of relativistic quantum field theory at low energies, without the need to introduce a neutrino mass, is seen to be compatible with all observations.Comment: 4 pages, no figures, final version to appear in JHEP, several changes in the presentation (including title), main conclusions are not modifie

    Supercooled Liquid Dynamics Studied via Shear-Mechanical Spectroscopy

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    We report dynamical shear-modulus measurements for five glass-forming liquids (pentaphenyl trimethyl trisiloxane, diethyl phthalate, dibutyl phthalate, 1,2-propanediol, and m-touluidine). The shear-mechanical spectra are obtained by the piezoelectric shear-modulus gauge (PSG) method. This technique allows one to measure the shear modulus (105101010^{5} -10^{10} Pa) of the liquid within a frequency range from 1 mHz to 10 kHz. We analyze the frequency-dependent response functions to investigate whether time-temperature superposition (TTS) is obeyed. We also study the shear-modulus loss-peak position and its high-frequency part. It has been suggested that when TTS applies, the high-frequency side of the imaginary part of the dielectric response decreases like a power law of the frequency with an exponent -1/2. This conjecture is analyzed on the basis of the shear mechanical data. We find that TTS is obeyed for pentaphenyl trimethyl trisiloxane and in 1,2-propanediol while in the remaining liquids evidence of a mechanical β\beta process is found. Although the the high-frequency power law behavior ωα\omega^{-\alpha} of the shear-loss may approach a limiting value of α=0.5\alpha=0.5 when lowering the temperature, we find that the exponent lies systematically above this value (around 0.4). For the two liquids without beta relaxation (pentaphenyl trimethyl trisiloxane and 1,2-propanediol) we also test the shoving model prediction, according to which the the relaxation-time activation energy is proportional to the instantaneous shear modulus. We find that the data are well described by this model.Comment: 7 pages, 6 figure

    Interplay between curvature and Planck-scale effects in astrophysics and cosmology

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    Several recent studies have considered the implications for astrophysics and cosmology of some possible nonclassical properties of spacetime at the Planck scale. The new effects, such as a Planck-scale-modified energy-momentum (dispersion) relation, are often inferred from the analysis of some quantum versions of Minkowski spacetime, and therefore the relevant estimates depend heavily on the assumption that there could not be significant interplay between Planck-scale and curvature effects. We here scrutinize this assumption, using as guidance a quantum version of de Sitter spacetime with known Inonu-Wigner contraction to a quantum Minkowski spacetime. And we show that, contrary to common (but unsupported) beliefs, the interplay between Planck-scale and curvature effects can be significant. Within our illustrative example, in the Minkowski limit the quantum-geometry deformation parameter is indeed given by the Planck scale, while in the de Sitter picture the parameter of quantization of geometry depends both on the Planck scale and the curvature scalar. For the much-studied case of Planck-scale effects that intervene in the observation of gamma-ray bursts we can estimate the implications of "quantum spacetime curvature" within robust simplifying assumptions. For cosmology at the present stage of the development of the relevant mathematics one cannot go beyond semiheuristic reasoning, and we here propose a candidate approximate description of a quantum FRW geometry, obtained by patching together pieces (with different spacetime curvature) of our quantum de Sitter. This semiheuristic picture, in spite of its limitations, provides rather robust evidence that in the early Universe the interplay between Planck-scale and curvature effects could have been particularly significant.Comment: 26 pages
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