316 research outputs found

    A scala library for spatial sensitivity analysis

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    The sensitivity analysis and validation of simulation models require specific approaches in the case of spatial models. We describe the spatialdata scala library providing such tools, including synthetic generators for urban configurations at different scales, spatial networks, and spatial point processes. These can be used to parametrize geosimulation models on synthetic configurations, and evaluate the sensitivity of model outcomes to spatial configuration. The library also includes methods to perturb real data, and spatial statistics indicators, urban form indicators, and network indicators. It is embedded into the OpenMOLE platform for model exploration, fostering the application of such methods without technical constraints

    Une synthÚse des modÚles de représentation des connaissances à base de Graphes Conceptuels et OWL

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    Nous prĂ©sentons et comparons deux approches de modĂ©lisation, formelles et concrĂštes, pour reprĂ©senter et manipuler des connaissances d’un domaine. Le modĂšle des graphes conceptuels permet de modĂ©liser des connaissances en terme de graphes, basĂ©s sur un support. Cette approche de modĂ©lisation est intensionnelle, est munie d’une sĂ©mantique en logique du premier ordre, et fait l’hypothĂšse d’un monde fermĂ© pour ses raisonnements. Le langage OWL permet de dĂ©crire des ontologies et des faits sur le Web, suivant une approche de modĂ©lisation extensionnelle. Il possĂšde une sĂ©mantique issue des logiques de descriptions, et fait l’hypothĂšse d’un monde ouvert pour ses raisonnements

    Quantitative full-colour transmitted light microscopy and dyes for concentration mapping and measurement of diffusion coefficients in microfluidic architectures

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    International audienceA simple and versatile methodology has been developed for the simultaneous measurement of multiple concentration profiles of colourants in transparent microfluidic systems, using a conventional transmitted light microscope, a digital colour (RGB) camera and numerical image processing combined with multicomponent analysis. Rigorous application of the Beer-Lambert law would require monochromatic probe conditions, but in spite of the broad spectral bandwidths of the three colour channels of the camera, a linear relation between the measured optical density and dye concentration is established under certain conditions. An optimised collection of dye solutions for the quantitative optical microscopic characterisation of microfluidic devices is proposed. Using the methodology for optical concentration measurement we then implement and validate a simplified and robust method for the microfluidic measurement of diffusion coefficients using an H-filter architecture. It consists of measuring the ratio of the concentrations of the two output channels of the H-filter. It enables facile determination of the diffusion coefficient, even for non-fluorescent molecules and nanoparticles, and is compatible with non-optical detection of the analyte

    High-accuracy mass determination of neutron-rich rubidium and strontiumiIsotopes

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    The penning-trap mass spectrometer ISOLTRAP, installed at the on-line isotope separator ISOLDE at CERN, has been used to measure atomic masses of 88,89,90m,91,92,93,94^{88,89,90m,91,92,93,94}Rb and 91−95^{91- 95}Sr. Using a resolving power of R  ⁣≈\!\scriptstyle\approx1 million a mass accuracy of typically 10 keV was achieved for all nuclides. Discrepancies with older data are analyzed and discussed, leading to corrections to those data. Together with the present ISOLTRAP data these corrected data have been used in the general mass adjustment

    Development and testing of Indoor Soundscape Questionnaire for evaluating contextual experience in public spaces

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    An Iï»żndoor Soundscape Questionnaire aiming at the evaluation of indoor public sound environments was designed, statistically tested and presented. It was established through initial pilot studies and three main factors under contextual experience variable are established as (1) psychological factors, (2) space usage factors and (3) demographical factors. In addition to the questions on demographical and space usage factors, detailed questions on psychological factors are designed and statistically tested for expectation, perception and reaction categories of the psychological factor. The questionnaire was applied as part of a case study in enclosed library foyer environments to a group of 270 participants through non-experimental survey data sampling. The reliability and validity scores of the Indoor Soundscape Questionnaire were statistically tested and confirmed. Furthermore, statistical tests were used to derive relationships between contextual experience variables of psychological, space usage and demographical factors. Chi-square test of goodness-of-fit results showed statistical significances of demographical and space usage factors with the psychological factors

    Magnetic field stabilization for high-accuracy mass measurements on exotic nuclides

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    The magnetic-field stability of a mass spectrometer plays a crucial role in precision mass measurements. In the case of mass determination of short-lived nuclides with a Penning trap, major causes of instabilities are temperature fluctuations in the vicinity of the trap and pressure fluctuations in the liquid helium cryostat of the superconducting magnet. Thus systems for the temperature and pressure stabilization of the Penning trap mass spectrometer ISOLTRAP at the ISOLDE facility at CERN have been installed. A reduction of the fluctuations by at least one order of magnitude downto dT=+/-5mK and dp=+/-50mtorr has been achieved, which corresponds to a relative frequency change of 2.7x10^{-9} and 1.5x10^{-10}, respectively. With this stabilization the frequency determination with the Penning trap only shows a linear temporal drift over several hours on the 10 ppb level due to the finite resistance of the superconducting magnet coils.Comment: 23 pages, 13 figure

    Collective modes in uniaxial incommensurate-commensurate systems with the real order parameter

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    The basic Landau model for uniaxial systems of the II class is nonintegrable, and allows for various stable and metastable periodic configurations, beside that representing the uniform (or dimerized) ordering. In the present paper we complete the analysis of this model by performing the second order variational procedure, and formulating the combined Floquet-Bloch approach to the ensuing nonstandard linear eigenvalue problem. This approach enables an analytic derivation of some general conclusions on the stability of particular states, and on the nature of accompanied collective excitations. Furthermore, we calculate numerically the spectra of collective modes for all states participating in the phase diagram, and analyze critical properties of Goldstone modes at all second order and first order transitions between disordered, uniform and periodic states. In particular it is shown that the Goldstone mode softens as the underlying soliton lattice becomes more and more dilute.Comment: 19 pages, 16 figures, REVTeX, to be published in Journal of Physics A: Mathematical and Genera

    A framework for improving urban soundscapes

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    Sound in public urban spaces is often considered in negative terms as both intrusive and undesirable - its referred to as noise! However, this issue is multi-facetted and goes much deeper than simply reducing levels. There are many positive aspects of a soundscape. In an attempt to progress thinking on positive soundscapes and move towards more practical planning approaches and decision making tools for soundscape assessment, this paper proposes an approach traditionally used in product development and manufacturing quality - The Kano Model. The approach is captured in the form of a broader framework which covers: the composition of a soundscape in objective terms; the factors affecting whether it might be perceived as positive; and how the Kano model for product development can be used as a means of understanding the range of applicability of approaches to create positive soundscapes (including several novel approaches which are the subject of other papers in this issue). It can be considered to be complementary with previous frameworks, some of which have concentrated on sound sources, others on the factors affecting perception or even as a model for understanding individual evaluation. In this case the motivation behind the framework is to help assess the likely impact of practical interventions on the positive aspects of a soundscape. The framework proposes that the meaning of "positive" for a public space is quite different for three types of people, each with a different level of direct engagement with the soundscape: planners; serious listeners; users of the space. The first two are influenced by the soundscape itself, either in meeting legislation and reducing nuisance, or as an artistic or creative opportunity. However the third, arguably most important group of people, users of the space, are more concerned with the space itself and have their perception of it influenced by the soundscape, which is an inconvenient and highly complex intermediate step. This influence is largely determined by their activity e.g. reading, holding a conversation, shopping or sightseeing. The paper discusses the further implementation of the framework, and how barriers to the wider application of the concept of positive soundscapes might be overcome. It shows how adapting an approach previously used in automotive sound quality can be adapted for urban soundscapes. It concludes with recommendations for taking the framework forward as a practical approach

    Ten years of Ana: lessons from a transdisciplinary body of literature on online pro-eating disorder websites

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    This paper offers a methodical review of the scientific literature of the last decade that concerns itself with online services offering supportive advocacy for anorexia nervosa and bulimia nervosa (‘pro-ana’ and ‘pro-mia’). The main question is whether these studies reproduce the traditional divide in the study of eating disorders, between clinical and social science perspectives, with limited mutual exchanges. Having first identified a specific body of literature, the authors investigate its content, methods and approaches, and analyse the network of cross-citations the components generate and share. On this basis, the authors argue that the scientific literature touching on pro-ana websites can be regarded as a single transdisciplinary body of knowledge. What’s more, they show that the literature on computermediated sociabilities centred on eating disorders displays different structural characteristics with respect to the traditional, non-Web-related research on eating disorders. In the latter, the social sciences have usually provided a critical counterpoint to the development of a health sciences mainstream. In the case of Web-related research, however, the social sciences have taken the lead role in defining the field, with the health sciences following suit
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