6,892 research outputs found

    Energy-Aware Cloud Management through Progressive SLA Specification

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    Novel energy-aware cloud management methods dynamically reallocate computation across geographically distributed data centers to leverage regional electricity price and temperature differences. As a result, a managed VM may suffer occasional downtimes. Current cloud providers only offer high availability VMs, without enough flexibility to apply such energy-aware management. In this paper we show how to analyse past traces of dynamic cloud management actions based on electricity prices and temperatures to estimate VM availability and price values. We propose a novel SLA specification approach for offering VMs with different availability and price values guaranteed over multiple SLAs to enable flexible energy-aware cloud management. We determine the optimal number of such SLAs as well as their availability and price guaranteed values. We evaluate our approach in a user SLA selection simulation using Wikipedia and Grid'5000 workloads. The results show higher customer conversion and 39% average energy savings per VM.Comment: 14 pages, conferenc

    The EULAR–OMERACT rheumatoid arthritis MRI reference image atlas: the metacarpophalangeal joints

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    This paper presents the metacarpophalangeal (MCP) joint magnetic resonance images of the EULAR–OMERACT rheumatoid arthritis MRI reference image atlas. The illustrations include synovitis in the MCP joints (OMERACT RA magnetic resonance imaging scoring system (RAMRIS), grades 0–3), bone oedema in the metacarpal head and the phalangeal base (grades 0–3), and bone erosion in the metacarpal head and the phalangeal base (grades 0–3, and examples of higher grades). The presented reference images can be used to guide scoring of MCP joints according to the OMERACT RA MRI scoring system

    Phosphorus Fertilizer and Stocking Rate Effects on Soil Microbial Biomass of a Long-Term Dairy Farmlet Experiment

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    The effects of a range of P fertilizer rates and dairy cow stocking rates on microbial biomass carbon and phosphorus were compared in a long-term farmlet trial in southeastern Australia. Pastures were stocked at 2, 3, or 4 cows/ha and received fertilizer at rates of 0, 35, 70 or 140 kgP/ha. There was no effect of either P fertilizer rate or stocking rate on microbial biomass C from 1995 to 1998. Increasing P application rate significantly increased the chloroform-released microbial P flush measured, but stocking rate had no effect on microbial P. There were significant temporal changes, with the seasonal effects of soil temperature and moisture overriding treatment effects on these microbial measurements

    The development of the EULAR–OMERACT rheumatoid arthritis MRI reference image atlas

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    Based on a previously developed rheumatoid arthritis MRI scoring system (OMERACT 2002 RAMRIS), the development team agreed which joints, MRI features, MRI sequences, and image planes would best illustrate the scoring system in an atlas. After collecting representative examples for all grades for each abnormality (synovitis, bone oedema, and bone erosion), the team met for a three day period to review the images and choose by consensus the most illustrative set for each feature, site, and grade. A predefined subset of images (for example, for erosion—all coronal slices through the bone) was extracted. These images were then re-read by the group at a different time point to confirm the scores originally assigned. Finally, all selected images were photographed and formatted by one centre and distributed to all readers for final approval

    Social media engagement and organic post effectiveness: A roadmap for increasing the effectiveness of social media use in hospitality industry

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    The present study assessed the social media use behavior of luxury hospitality facilities and offers suggestions to improve organic post effectiveness. All five-star tourism facilities operating in Turkey were incorporated into the study and publicly available post data on Facebook accounts of 441 facilities (out of a total of 612) were examined in the high tourist season (August) for one month. Data on 2,012 Facebook posts were obtained manually and filtered down to 1,847. The collected post data were subsequently coded using a content analysis form and analyzed via ordinal regression. The results highlighted the positive effects of interactive content and vivid content as well as the significance of the content type in achieving higher interaction among followers. The facility location and category (hotel, holiday village, thermal hotel) also emerged as significant factors affecting follower interactions

    Characteristics of Adults Who Use Prayer as an Alternative Therapy

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    Purpose: To describe the demographics, health-related and preventive-health behaviors, health status, and health care charges of adults who do and do not pray for health. Design: Cross-sectional survey with 1-year follow-up. Setting: A Minnesota health plan. Subjects: A stratified random sample of 5107 members age 40 and over with analysis based on 4404 survey respondents (86%). Measures: Survey data included health risks, health practices, use of preventive health services, satisfaction with care, and use of alternative therapies. Health care charges were obtained from administrative data. Results: Overall, 47.2% of study subjects reported that they pray for health, and 90.3% of these believed prayer improved their health. After adjustment for demographics, those who pray had significantly less smoking and alcohol use and more preventive care visits, influenza immunizations, vegetable intake, satisfaction with care, and social support and were more likely to have a regular primary care provider. Rates of functional impairment, depressive symptoms, chronic diseases, and total health care charges were not related to prayer. Conclusions: Those who pray had more favorable health-related behaviors, preventive service use, and satisfaction with care. Discussion of prayer could help guide customization of clinical care. Research that examines the effect of prayer on health status should adjust for variables related both to use of prayer and to health status

    Optimizing a Certified Proof Checker for a Large-Scale Computer-Generated Proof

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    In recent work, we formalized the theory of optimal-size sorting networks with the goal of extracting a verified checker for the large-scale computer-generated proof that 25 comparisons are optimal when sorting 9 inputs, which required more than a decade of CPU time and produced 27 GB of proof witnesses. The checker uses an untrusted oracle based on these witnesses and is able to verify the smaller case of 8 inputs within a couple of days, but it did not scale to the full proof for 9 inputs. In this paper, we describe several non-trivial optimizations of the algorithm in the checker, obtained by appropriately changing the formalization and capitalizing on the symbiosis with an adequate implementation of the oracle. We provide experimental evidence of orders of magnitude improvements to both runtime and memory footprint for 8 inputs, and actually manage to check the full proof for 9 inputs.Comment: IMADA-preprint-c

    On the "renormalization" transformations induced by cycles of expansion and contraction in causal set cosmology

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    We study the ``renormalization group action'' induced by cycles of cosmic expansion and contraction, within the context of a family of stochastic dynamical laws for causal sets derived earlier. We find a line of fixed points corresponding to the dynamics of transitive percolation, and we prove that there exist no other fixed points and no cycles of length two or more. We also identify an extensive ``basin of attraction'' of the fixed points but find that it does not exhaust the full parameter space. Nevertheless, we conjecture that every trajectory is drawn toward the fixed point set in a suitably weakened sense.Comment: 22 pages, 1 firgure, submitted to Phys. Rev.

    Drip Paintings and Fractal Analysis

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    It has been claimed [1-6] that fractal analysis can be applied to unambiguously characterize works of art such as the drip paintings of Jackson Pollock. This academic issue has become of more general interest following the recent discovery of a cache of disputed Pollock paintings. We definitively demonstrate here, by analyzing paintings by Pollock and others, that fractal criteria provide no information about artistic authenticity. This work has also led to two new results in fractal analysis of more general scientific significance. First, the composite of two fractals is not generally scale invariant and exhibits complex multifractal scaling in the small distance asymptotic limit. Second the statistics of box-counting and related staircases provide a new way to characterize geometry and distinguish fractals from Euclidean objects
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