2,921 research outputs found

    Exploring Outliers in Crowdsourced Ranking for QoE

    Full text link
    Outlier detection is a crucial part of robust evaluation for crowdsourceable assessment of Quality of Experience (QoE) and has attracted much attention in recent years. In this paper, we propose some simple and fast algorithms for outlier detection and robust QoE evaluation based on the nonconvex optimization principle. Several iterative procedures are designed with or without knowing the number of outliers in samples. Theoretical analysis is given to show that such procedures can reach statistically good estimates under mild conditions. Finally, experimental results with simulated and real-world crowdsourcing datasets show that the proposed algorithms could produce similar performance to Huber-LASSO approach in robust ranking, yet with nearly 8 or 90 times speed-up, without or with a prior knowledge on the sparsity size of outliers, respectively. Therefore the proposed methodology provides us a set of helpful tools for robust QoE evaluation with crowdsourcing data.Comment: accepted by ACM Multimedia 2017 (Oral presentation). arXiv admin note: text overlap with arXiv:1407.763

    Dependence of X-Ray Burst Models on Nuclear Reaction Rates

    Full text link
    X-ray bursts are thermonuclear flashes on the surface of accreting neutron stars and reliable burst models are needed to interpret observations in terms of properties of the neutron star and the binary system. We investigate the dependence of X-ray burst models on uncertainties in (p,Ξ³\gamma), (Ξ±\alpha,Ξ³\gamma), and (Ξ±\alpha,p) nuclear reaction rates using fully self-consistent burst models that account for the feedbacks between changes in nuclear energy generation and changes in astrophysical conditions. A two-step approach first identified sensitive nuclear reaction rates in a single-zone model with ignition conditions chosen to match calculations with a state-of-the-art 1D multi-zone model based on the {\Kepler} stellar evolution code. All relevant reaction rates on neutron deficient isotopes up to mass 106 were individually varied by a factor of 100 up and down. Calculations of the 84 highest impact reaction rate changes were then repeated in the 1D multi-zone model. We find a number of uncertain reaction rates that affect predictions of light curves and burst ashes significantly. The results provide insights into the nuclear processes that shape X-ray burst observables and guidance for future nuclear physics work to reduce nuclear uncertainties in X-ray burst models.Comment: 24 pages, 13 figures, 4 tables, submitte

    Proton Drip-Line Calculations and the Rp-process

    Get PDF
    One-proton and two-proton separation energies are calculated for proton-rich nuclei in the region A=41βˆ’75 A=41-75 . The method is based on Skyrme Hartree-Fock calculations of Coulomb displacement energies of mirror nuclei in combination with the experimental masses of the neutron-rich nuclei. The implications for the proton drip line and the astrophysical rp-process are discussed. This is done within the framework of a detailed analysis of the sensitivity of rp process calculations in type I X-ray burst models on nuclear masses. We find that the remaining mass uncertainties, in particular for some nuclei with N=ZN=Z, still lead to large uncertainties in calculations of X-ray burst light curves. Further experimental or theoretical improvements of nuclear mass data are necessary before observed X-ray burst light curves can be used to obtain quantitative constraints on ignition conditions and neutron star properties. We identify a list of nuclei for which improved mass data would be most important.Comment: 20 pages, 9 figures, 2 table

    Models for Type I X-Ray Bursts with Improved Nuclear Physics

    Get PDF
    Multi-zone models of Type I X-ray bursts are presented that use an adaptive nuclear reaction network of unprecedented size, up to 1300 isotopes. Sequences of up to 15 bursts are followed for two choices of accretion rate and metallicity. At 0.1 Eddington (and 0.02 Eddington for low metallicity), combined hydrogen-helium flashes occur. The rise times, shapes, and tails of these light curves are sensitive to the efficiency of nuclear burning at various waiting points along the rp-process path and these sensitivities are explored. The bursts show "compositional inertia", in that their properties depend on the fact that accretion occurs onto the ashes of previous bursts which contain left-over hydrogen, helium and CNO nuclei. This acts to reduce the sensitivity of burst properties to metallicity. For the accretion rates studied, only the first anomalous burst in one model produces nuclei as heavy as A=100, other bursts make chiefly nuclei with A~64. The amount of carbon remaining after hydrogen-helium bursts is typically <1% by mass, and decreases further as the ashes are periodically heated by subsequent bursts. At the lower accretion rate of 0.02 Eddington and solar metallicity, the bursts ignite in a hydrogen-free helium layer. At the base of this layer, up to 90% of the helium has already burned to carbon prior to the unstable ignition. These helium-ignited bursts have briefer, brighter light curves with shorter tails, very rapid rise times (<0.1 s), and ashes lighter than the iron group.Comment: Submitted to the Astrophysical Journal (42 pages; 27 figures

    Entwicklung eines regionalen Ausbildungsmodells β€žΓ–kolandbau und Vermarktungβ€œ an der Fachhochschule Eberswalde im Rahmen des BundesfΓΆrderprogramms Regionen Aktiv

    Get PDF
    In September 2004 a new B. Sc. study course for Organic Farming and Marketing started at the University of Applied Sciences Eberswalde. Supported by the Federal Ministry of Consumer Protection, Food and Agriculture program β€œRegionen Aktiv” an innovative education model was established. Focussing on rural development farmers, processors and trading partners were involved in the development of topics for the study programme

    Onset of Surface-Tension-Driven Benard Convection

    Full text link
    Experiments with shadowgraph visualization reveal a subcritical transition to a hexagonal convection pattern in thin liquid layers that have a free upper surface and are heated from below. The measured critical Marangoni number (84) and observation of hysteresis (3%) agree with theory. In some experiments, imperfect bifurcation is observed and is attributed to deterministic forcing caused in part by the lateral boundaries in the experiment.Comment: 4 pages. The RevTeX file has a macro allowing various styles. The appropriate style is "mypprint" which is the defaul

    Transport of Proteins into Mitochondria

    Get PDF
    The mitochondrial ADP/ATP carrier is an integral transmembrane protein of the inner membrane. It is synthesized on cytoplasmic ribosomes. Kinetic data suggested that this protein is transferred into mitochondria in a posttranslational manner. The following results provide further evidence for such a mechanism and provide information on its details. 1. In homologous and heterologous translation systems the newly synthesized ADP/ATP carrier protein is present in the postribosomal supernatant. 2. Analysis by density gradient centrifugation and gel filtration shows, that the ADP/ATP carrier molecules in the postribosomal fraction are present as soluble complexes with apparent molecular weights of about 120000 and 500000 or larger. The carrier binds detergents such as Triton X-100 and deoxycholate forming mixed micelles with molecular weights of about 200000–400000. 3. Incubation of a postribosomal supernatant of a reticulocyte lysate containing newly synthesized ADP/ATP carrier with mitochondria isolated from Neurospora spheroplasts results in efficient transfer of the carrier into mitochondria. About 20–30% of the transferred carrier are resistant to proteinase in whole mitochondria. The authentic mature protein is also largely resistant to proteinase in whole mitochondria and sensitive after lysis of mitochondria with detergent. Integrity of mitochondria is a prerequisite for translocation into proteinase resistant position. 4. The transfer in vitro into a proteinase-resistant form is inhibited by the uncoupler carbonyl-cyanide m-chlorophenylhydrazone but not the proteinase-sensitive binding. These observations suggest that the posttranslational transfer of ADP/ATP carrier occurs via the cytosolic space through a soluble oligomeric precursor form. This precursor is taken up by intact mitochondria into an integral position in the membrane. These findings are considered to be of general importance for the intracellular transfer of insoluble membrane proteins. They support the view that such proteins can exist in a water-soluble form its precursors and upon integration into the membrane undergo a conformational change. Uptake into the membrane may involve the cleavage of an additional sequence in some proteins, but this appears not to be a prerequisite as demonstrated by the ADP/ATP carrier protein

    ИсслСдованиС влияния ΠΌΠ°Π³Π½ΠΈΡ‚Π½ΠΎΠ³ΠΎ поля ΠΈ ΠΏΠΎΡ‚Π΅Π½Ρ†ΠΈΠ°Π»Π° смСщСния Π½Π° ΠΏΠΎΠ΄Π°Π²Π»Π΅Π½ΠΈΠ΅ ΠΌΠ΅Π΄Π½Ρ‹Ρ… макрочастиц Π²Π°ΠΊΡƒΡƒΠΌΠ½ΠΎ-Π΄ΡƒΠ³ΠΎΠ²ΠΎΠ³ΠΎ испаритСля

    Get PDF
    ΠžΠ±ΡŠΠ΅ΠΊΡ‚ΠΎΠΌ исслСдования ΡΠ²Π»ΡΡŽΡ‚ΡΡ ΠΌΠ°Π³Π½ΠΈΡ‚Π½ΠΎΠ΅ ΠΏΠΎΠ»Π΅ ΠΈ ΠΎΡ‚Ρ€ΠΈΡ†Π°Ρ‚Π΅Π»ΡŒΠ½Ρ‹ΠΉ ΠΊΠΎΡ€ΠΎΡ‚ΠΊΠΎΠΈΠΌΠΏΡƒΠ»ΡŒΡΠ½Ρ‹ΠΉ ΠΏΠΎΡ‚Π΅Π½Ρ†ΠΈΠ°Π» смСщСния, Π²Π»ΠΈΡΡŽΡ‰ΠΈΠ΅ Π½Π° ΠΏΠΎΠ΄Π°Π²Π»Π΅Π½ΠΈΠ΅ ΠΌΠ΅Π΄Π½Ρ‹Ρ… макрочастиц Π²Π°ΠΊΡƒΡƒΠΌΠ½ΠΎ-Π΄ΡƒΠ³ΠΎΠ²ΠΎΠ³ΠΎ испаритСля. ЦСль Ρ€Π°Π±ΠΎΡ‚Ρ‹ – исслСдованиС закономСрностСй формирования ΠΏΠΎΡ‚ΠΎΠΊΠ° ΠΌΠΈΠΊΡ€ΠΎΠΊΠ°ΠΏΠ΅Π»ΡŒΠ½ΠΎΠΉ Ρ„Ρ€Π°ΠΊΡ†ΠΈΠΈ Π²Π°ΠΊΡƒΡƒΠΌΠ½ΠΎ-Π΄ΡƒΠ³ΠΎΠ²ΠΎΠ³ΠΎ испаритСля ΠΈ ΡƒΠ²Π΅Π»ΠΈΡ‡Π΅Π½ΠΈΠ΅ эффСктивности подавлСния макрочастиц ΠΏΡ€ΠΈ использовании ΠΌΠ°Π³Π½ΠΈΡ‚Π½ΠΎΠ³ΠΎ поля ΠΈ ΠΏΡ€ΠΈΠ»ΠΎΠΆΠ΅Π½ΠΈΠΈ ΠΊ ΠΏΠΎΡ‚Π΅Π½Ρ†ΠΈΠ°Π»ΡŒΠ½ΠΎΠΉ мишСни высокочастотного ΠΊΠΎΡ€ΠΎΡ‚ΠΊΠΎΠΈΠΌΠΏΡƒΠ»ΡŒΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΡ‚Π΅Π½Ρ†ΠΈΠ°Π»Π° смСщСния.The object of the study are the magnetic field and short-pulse negative bias potential, influencing the suppression of copper macroparticles of vacuum arc evaporator. Purpose – the study of regularities of formation of flow micro-fraction of the vacuum-arc evaporator and increasing the efficiency of suppression of particulates when using magnetic field and application to potential targets of high-frequency short-pulse bias potential
    • …
    corecore