5,137 research outputs found

    Tractable approximate deduction for OWL

    Get PDF
    Acknowledgements This work has been partially supported by the European project Marrying Ontologies and Software Technologies (EU ICT2008-216691), the European project Knowledge Driven Data Exploitation (EU FP7/IAPP2011-286348), the UK EPSRC project WhatIf (EP/J014354/1). The authors thank Prof. Ian Horrocks and Dr. Giorgos Stoilos for their helpful discussion on role subsumptions. The authors thank Rafael S. Gonçalves et al. for providing their hotspots ontologies. The authors also thank BoC-group for providing their ADOxx Metamodelling ontologies.Peer reviewedPostprin

    Ages and Masses of 0.64 million Red Giant Branch stars from the LAMOST Galactic Spectroscopic Survey

    Full text link
    We present a catalog of stellar age and mass estimates for a sample of 640\,986 red giant branch (RGB) stars of the Galactic disk from the LAMOST Galactic Spectroscopic Survey (DR4). The RGB stars are distinguished from the red clump stars utilizing period spacing derived from the spectra with a machine learning method based on kernel principal component analysis (KPCA). Cross-validation suggests our method is capable of distinguishing RC from RGB stars with only 2 per cent contamination rate for stars with signal-to-noise ratio (SNR) higher than 50. The age and mass of these RGB stars are determined from their LAMOST spectra with KPCA method by taking the LAMOST - KeplerKepler giant stars having asteroseismic parameters and the LAMOST-TGAS sub-giant stars based on isochrones as training sets. Examinations suggest that the age and mass estimates of our RGB sample stars with SNR >> 30 have a median error of 30 per cent and 10 per cent, respectively. Stellar ages are found to exhibit positive vertical and negative radial gradients across the disk, and the age structure of the disk is strongly flared across the whole disk of 6<R<136<R<13\,kpc. The data set demonstrates good correlations among stellar age, [Fe/H] and [α\alpha/Fe]. There are two separate sequences in the [Fe/H] -- [α\alpha/Fe] plane: a high--α\alpha sequence with stars older than \sim\,8\,Gyr and a low--α\alpha sequence composed of stars with ages covering the whole range of possible ages of stars. We also examine relations between age and kinematic parameters derived from the Gaia DR2 parallax and proper motions. Both the median value and dispersion of the orbital eccentricity are found to increase with age. The vertical angular momentum is found to fairly smoothly decrease with age from 2 to 12\,Gyr, with a rate of about -50\,kpc\,km\,s1^{-1}\,Gyr1^{-1}. A full table of the catalog is public available online.Comment: 16 pages, 22 figures,accepted by MNRA

    Using Machine Learning to Optimize Web Interactions on Heterogeneous Mobile Systems

    Get PDF
    The web has become a ubiquitous application development platform for mobile systems. Yet, web access on mobile devices remains an energy-hungry activity. Prior work in the field mainly focuses on the initial page loading stage, but fails to exploit the opportunities for energy-efficiency optimization while the user is interacting with a loaded page. This paper presents a novel approach for performing energy optimization for interactive mobile web browsing. At the heart of our approach is a set of machine learning models, which estimate at runtime the frames per second for a given user interaction input by running the computation-intensive web render engine on a specific processor core under a given clock speed. We use the learned predictive models as a utility function to quickly search for the optimal processor setting to carefully trade responsive time for reduced energy consumption. We integrate our techniques to the open-source Chromium browser and apply it to two representative mobile user events: scrolling and pinching (i.e., zoom in and out). We evaluate the developed system on the landing pages of the top-100 hottest websites and two big.LITTLE heterogeneous mobile platforms. Our extensive experiments show that the proposed approach reduces the system-wide energy consumption by over 36% on average and up to 70%. This translates to an over 17% improvement on energy-efficiency over a state-of-the-art event-based web browser scheduler, but with significantly fewer violations on the quality of service

    Hierarchical structures from inorganic nanocrystal self-assembly for photoenergy utilization

    Get PDF
    Self-assembly has emerged as a powerful strategy for controlling the structure and physicochemical properties of ensembles of inorganic nanocrystals. Hierarchical structures from nanocrystal assembly show collective properties that differ from individual nanocrystals and bulk samples. Incorporation of structural hierarchy into nanostructures is of great importance as a result of enhancing mass transportation, reducing resistance to diffusion, and high surface areas for adsorption and reaction, and thus much effort has been devoted to the exploration of various novel organizing schemes through which inorganic porous structure with architectural design can be created. In this paper, the recent research progress in this field is reviewed. The general strategies for the synthesis of hierarchical structures assembled from nanobuilding blocks are elaborated. The well-defined hierarchical structures provide new opportunities for optimizing, tuning, and/or enhancing the properties and performance of these materials and have found applications in photoenergy utilization including photodegradation, photocatalytic H2 production, photocatalytic CO2 conversion, and sensitized solar cells, and these are discussed illustratively.Yun-Pei Zhu, Tie-Zhen Ren, Tian-Yi Ma, and Zhong-Yong Yua

    In vitro Protective Effect of Ganoderol A Isolated from Ganadermalucidum Against Ultraviolet A Radiation and its Anti-inflammatory Properties

    Get PDF
    Purpose: To evaluate the ultraviolet A (UVA) protection and anti-inflammatory activity of ganoderol A extracted from Ganodermalucidum.Methods: The cytotoxicity and in vitro protective effect of ganoderol A against UVA damage were evaluated by MTT assay. Apoptosis and cell-cycle arrest of NIH/3T3 fibroblast cells were assayed by fluorescence-activated cell sorting (FCS). Expression of monocyte chemotactic protein-1 (MCP-1) and inducible nitric oxide synthase (iNOS) were determined using quantitative real-time polymerase chain reaction (qPCR).Results: The results indicate that the maximal non-toxic concentration of ganoderol A in NIH/3T3 cells and RAW 264.7 macrophages was 50 and 25 μg/mL respectively. DNA in the tails and tail length decreased by 55 and 70 %, respectively, in the group pretreated with ganoderol A compared with the UVA-treated group. G1 phase cells decreased by 23 %, whereas the number of apoptotic cells returned to normal. The expression of MCP-1 and iNOS declined to 60 and 15 %, respectively, compared with LPS-stimulated group.Conclusion: Ganoderol A has significant anti-inflammatory activity and protection against UVA damage, thus suggesting that the compound is a  candidate for the development of a suitable product to protect skin from UV-induced photoaging.Keywords: Anti-ultraviolet A, Anti-inflammatory, Ganoderol A, Ganodermalucidum, Photoagin
    corecore