3,249 research outputs found

    Super-hydrodynamic limit in interacting particle systems

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    This paper is a follow-up of the work initiated in [3], where it has been investigated the hydrodynamic limit of symmetric independent random walkers with birth at the origin and death at the rightmost occupied site. Here we obtain two further results: first we characterize the stationary states on the hydrodynamic time scale and show that they are given by a family of linear macroscopic profiles whose parameters are determined by the current reservoirs and the system mass. Then we prove the existence of a super-hyrdrodynamic time scale, beyond the hydrodynamic one. On this larger time scale the system mass fluctuates and correspondingly the macroscopic profile of the system randomly moves within the family of linear profiles, with the randomness of a Brownian motion.Comment: 22 page

    Non equilibrium stationary state for the SEP with births and deaths

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    We consider the symmetric simple exclusion process in the interval \La_N:=[-N,N]\cap\mathbb Z with births and deaths taking place respectively on suitable boundary intervals I+I_+ and I−I_-, as introduced in De Masi et al. (J. Stat. Phys. 2011). We study the stationary measure density profile in the limit $N\to\infty

    Symmetric simple exclusion process with free boundaries

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    We consider the one dimensional symmetric simple exclusion process (SSEP) with additional births and deaths restricted to a subset of configurations where there is a leftmost hole and a rightmost particle. At a fixed rate birth of particles occur at the position of the leftmost hole and at the same rate, independently, the rightmost particle dies. We prove convergence to a hydrodynamic limit and discuss its relation with a free boundary problem.Comment: 29 pages, 4 figure

    STRATEGIES OF DIGITAL KNOWLEDGE'S REPRESENTATION: FROM DE-MORPHOGENESIS AT MSH-BIM. OPTICAL, THEATRICAL ILLUSION AND PERSPECTIVE IN THE NEAPOLITAN SCHOOL'S ARCHITECTURE DRAWING

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    Abstract. The study illustrates the architectural-scenographic construction and drawing techniques related to theatrical scenic illusionism of the seventeenth and eighteenth centuries in relationship with some Neapolitan monumental buildings. In addition the develop of methodologies of intervention DSH (De-Morphogenesis, Semantic, Hypermedia Systems) – BIM (Building Information Modelling) in the historical reality as new concept of "Smart Heritage". Therefore, the objective of the research is the construction of the visual model of documentation defined as "Digital Platform for the Knowledge's Representation" of classification and comparison data. The methodological operations will be based on the "Morphology of the Form", the "De-Morphogenesis of the Architecture", "Semantic Values of the Architecture by On-Morphogenesis and "Hypermedia Systems and Cloud Computing Platforms". The research highlighted for architectural elements: 1) Lexicon, Syntax and Semantics. 2) Ripercussion on representative categories. 3) Solutions adopted to check the conservation condition. 4) manipulation based on dimensional parameters. 5) 3D parametric digital models with appropriate stylistic features in the same way as reverse engineering solutions

    DIGITAL DOCUMENTATION'S ONTOLOGY: CONTEMPORARY DIGITAL REPRESENTATIONS AS EXPRESS AND SHARED MODELS OF REGENERATION AND RESILIENCE IN THE PLATFORM BIM/CONTAMINATED HYBRID REPRESENTATION

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    Abstract. The study illustrates a university research project of "Digital Documentation's Ontology", to be activated with other universities, of an Platform (P) – Building Information Modeling (BIM) articulated on a Contaminated Hybrid Representation (diversification of graphic models); the latter, able to foresee categories of Multi-Representations that interact with each other for to favour several representations, adapted to a different information density in the digital multi-scale production, is intended as platform (grid of data and information at different scales, semantic structure from web content, data and information storage database, archive, model and form of knowledge and ontological representation shared) of: inclusive digital ecosystem development; digital regenerative synergies of representation with adaptable and resilient content in hybrid or semi-hybrid Cloud environments; phenomenological reading of the changing complexity of environmental reality; hub solution of knowledge and simulcast description of information of Cultural Heritage (CH); multimedia itineraries to enhance participatory and attractive processes for the community; factor of cohesion and sociality, an engine of local development. The methodology of P-BIM/CHR is articulated on the following ontologies: Interpretative and Codification, Morphology, Lexicon, Syntax, Metamorphosis, Metadata in the participatory system, Regeneration, Interaction and Sharing. From the point of view the results and conclusion the study allowed to highlight: a) Digital Regenerative synergies of representation; b) Smart CH Model for an interconnection of systems and services within a complex set of relationships

    Optimal strategy for polarization modulation in the LSPE-SWIPE experiment

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    Context. Cosmic microwave background (CMB) B-mode experiments are required to control systematic effects with an unprecedented level of accuracy. Polarization modulation by a half wave plate (HWP) is a powerful technique able to mitigate a large number of the instrumental systematics. Aims. Our goal is to optimize the polarization modulation strategy of the upcoming LSPE-SWIPE balloon-borne experiment, devoted to the accurate measurement of CMB polarization at large angular scales. Methods. We departed from the nominal LSPE-SWIPE modulation strategy (HWP stepped every 60 s with a telescope scanning at around 12 deg/s) and performed a thorough investigation of a wide range of possible HWP schemes (either in stepped or continuously spinning mode and at different azimuth telescope scan-speeds) in the frequency, map and angular power spectrum domain. In addition, we probed the effect of high-pass and band-pass filters of the data stream and explored the HWP response in the minimal case of one detector for one operation day (critical for the single-detector calibration process). We finally tested the modulation performance against typical HWP-induced systematics. Results. Our analysis shows that some stepped HWP schemes, either slowly rotating or combined with slow telescope modulations, represent poor choices. Moreover, our results point out that the nominal configuration may not be the most convenient choice. While a large class of spinning designs provides comparable results in terms of pixel angle coverage, map-making residuals and BB power spectrum standard deviations with respect to the nominal strategy, we find that some specific configurations (e.g., a rapidly spinning HWP with a slow gondola modulation) allow a more efficient polarization recovery in more general real-case situations. Conclusions. Although our simulations are specific to the LSPE-SWIPE mission, the general outcomes of our analysis can be easily generalized to other CMB polarization experiments

    Slow motion and metastability for a non local evolution equation

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    In this paper we consider a non local evolution mean field equation proving the existence of an invariant, unstable, one dimensional manifold connecting the critical droplet with the stable and the metastable phases. We prove that the points on the manifold are droplets longer or shorter than the critical one, and that their motion is very slow in agreement with the theory of metastable patterns
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