11,688 research outputs found

    Parallel waveform extraction algorithms for the Cherenkov Telescope Array Real-Time Analysis

    Get PDF
    The Cherenkov Telescope Array (CTA) is the next generation observatory for the study of very high-energy gamma rays from about 20 GeV up to 300 TeV. Thanks to the large effective area and field of view, the CTA observatory will be characterized by an unprecedented sensitivity to transient flaring gamma-ray phenomena compared to both current ground (e.g. MAGIC, VERITAS, H.E.S.S.) and space (e.g. Fermi) gamma-ray telescopes. In order to trigger the astrophysics community for follow-up observations, or being able to quickly respond to external science alerts, a fast analysis pipeline is crucial. This will be accomplished by means of a Real-Time Analysis (RTA) pipeline, a fast and automated science alert trigger system, becoming a key system of the CTA observatory. Among the CTA design key requirements to the RTA system, the most challenging is the generation of alerts within 30 seconds from the last acquired event, while obtaining a flux sensitivity not worse than the one of the final analysis by more than a factor of 3. A dedicated software and hardware architecture for the RTA pipeline must be designed and tested. We present comparison of OpenCL solutions using different kind of devices like CPUs, Graphical Processing Unit (GPU) and Field Programmable Array (FPGA) cards for the Real-Time data reduction of the Cherenkov Telescope Array (CTA) triggered data.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

    Ab initio molecular dynamics simulations of Aluminum solvation

    Full text link
    The solvation of Al and its hydrolyzed species in water clusters has been studied by means of ab initio molecular dynamics simulations. The hexa-hydrate aluminum ion formed a stable complex in the finite temperature cluster simulation of one aluminum ion and 16 waters. The average dipole moment of strongly polarized hydrated water molecules in the first solvation shell of the hexa-hydrate aluminum ion was found to be 5.02 Debye. The deprotonated hexa-hydrate complex evolves into a tetra-coordinated aluminate ion with two water molecules in the second solvation shell forming hydrogen bonds to the hydroxyl groups in agreement with the observed coordination.Comment: 12 pages in Elsevier LaTeX, 5 figures in Postscript, 2 last figures are in color, submitted to Chemical Physics Letter

    Quantum Fluctuations Driven Orientational Disordering: A Finite-Size Scaling Study

    Full text link
    The orientational ordering transition is investigated in the quantum generalization of the anisotropic-planar-rotor model in the low temperature regime. The phase diagram of the model is first analyzed within the mean-field approximation. This predicts at T=0T=0 a phase transition from the ordered to the disordered state when the strength of quantum fluctuations, characterized by the rotational constant Θ\Theta, exceeds a critical value ΘcMF\Theta_{\rm c}^{MF}. As a function of temperature, mean-field theory predicts a range of values of Θ\Theta where the system develops long-range order upon cooling, but enters again into a disordered state at sufficiently low temperatures (reentrance). The model is further studied by means of path integral Monte Carlo simulations in combination with finite-size scaling techniques, concentrating on the region of parameter space where reentrance is predicted to occur. The phase diagram determined from the simulations does not seem to exhibit reentrant behavior; at intermediate temperatures a pronounced increase of short-range order is observed rather than a genuine long-range order.Comment: 27 pages, 8 figures, RevTe

    Low-cost bus business models and the case of Brazil

    Get PDF
    Purpose – The purpose of this paper is to identify low-costbus business models from different parts of the world and check their applicability in the Brazilian market. It also identifies crucial factors for the development of that kind of business and investigates the relationship between low-cost buses and other modes of transport. This research analyzes every relevant aspect to the applicability of low-cost business models in Brazil, driving to discussions and conclusions. The gains on the development of low-cost bus systems in Brazil may have a wide reach, from personal to general public benefits. Design/methodology/approach – Business models for low-cost bus systems are used to analyze in a qualitative approach. The data are collected through semi-structured interviews, direct observations and documental basis. In addition, innovations over the previous five years are evaluated in order to establish a comparative pattern between companies. Findings – There is a great potential in the Brazilian passenger market for the entrance of low-cost bus companies. The only question is just when it is the right time to enter that market. Most of the negative points presented for the implementation of a low-cost company are related to the current economical and political crisis in Brazil. It was identified as a potential cause for the overall decrease of the passengers market in recent years, and specifically of the bus passengers market. Originality/value – The recent regulation changes, the high demand for passengers and even the similarity of possible routes in Brazil to the ones in Europe and in the USA make Brazil a fertile soil for the development of that kind of business. A similar price mechanism to the ones applied worldwide was also identified as doable in Brazil

    ORGANIZATIONAL STRUCTURES TO SUPPORT INNOVATION: HOW DO COMPANIES DECIDE?

    Get PDF
    The purpose of this work is to discuss the issue of how companies aiming to increase their innovative capacity should decide about their organizational structure. To accomplish this goal, a bibliographic review about the theme was carried out, as well as an exploratory research, conducted by case study in a Brazilian petrochemical company that had recently re-organised its structure regarding innovative activities. The results suggest that the studied company decided upon its organisational structure without considering the whole process of innovation, focusing efforts only on the Research and Development area. Its organizational structure is still based on traditional forms, with centralized decisions and well demarcated functions. A more “adhocratic” structure, considering innovation as an integrated process would foster the company innovative capacity in the future.The purpose of this work is to discuss the issue of how companies aiming to increase their innovative capacity should decide about their organizational structure. To accomplish this goal, a bibliographic review about the theme was carried out, as well as an exploratory research, conducted by case study in a Brazilian petrochemical company that had recently re-organised its structure regarding innovative activities. The results suggest that the studied company decided upon its organisational structure without considering the whole process of innovation, focusing efforts only on the Research and Development area. Its organizational structure is still based on traditional forms, with centralized decisions and well demarcated functions. A more “adhocratic” structure, considering innovation as an integrated process would foster the company innovative capacity in the future
    corecore