2,250 research outputs found

    Accounting for preemption and migration costs in the calculation of hard real-time cyclic executives for MPSoCs

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    This work introduces a methodology to consider preemption and migration overhead in hard real-time cyclic executives on multicore architectures. The approach performs two iterative stages. The first stage takes a cyclic executive, from which the number and timing of all preemptions and migrations for every task is known. Then, it includes this overhead by updating the worst-case execution time (WCET) of the tasks. The second stage calculates a new cyclic executive considering the new WCET of tasks. The stages iterate until the preemption and migration overhead keeps constant. © 2016 IEEE

    Energy-Efficient Thermal-Aware Scheduling for RT Tasks Using TCPN

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    This work leverages TCPNs to design an energy-efficient, thermal-aware real-time scheduler for a multiprocessor system that normally runs in a low state energy at maximum system utilization but its capable of increasing the clock frequency to serve aperiodic tasks, optimizing energy, and honoring temporal and thermal constraints. An off-line stage computes the minimum frequency required to run the periodic tasks at maximum CPU utilization, the proportion of each task''s job to be run on each CPU, the maximum clock frequency that keeps temperature under a limit, and the available cycles (slack) with respect to the system with minimum frequency. Then, a Zero-Laxity online scheduler dispatches the periodic tasks according to the offline calculation. Upon the arrival of aperiodic tasks, it increases clock frequency in such a way that all periodic and aperiodic tasks are properly executed. Thermal and temporal requirements are always guaranteed, and energy consumption is minimized

    Studying and Constructing Concept Maps: A Meta-Analysis

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    A concept map is a node-link diagram in which each node represents a concept and each link identifies the relationship between the two concepts it connects. We investigated how using concept maps influences learning by synthesizing the results of 142 independent effect sizes (n = 11,814). A random-effects model meta-analysis revealed that learning with concept and knowledge maps produced a moderate, statistically significant effect (g =.58, p < .001). A moderator analysis revealed that creating concept maps (g =.72, p < .001) was associated with greater benefit relative to respective comparison conditions than studying concept maps (g = .43, p <.001). Additional moderator analyses indicated learning with concept maps was superior to other instructional comparison conditions, and was effective across science, technology, engineering, and math (STEM) and non-STEM knowledge domains. Further moderator analyses, as well as implications for theory and practice, are provided

    Superscaling in electroweak excitation of nuclei

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    Superscaling properties of 12C, 16O and 40Ca nuclear responses, induced by electron and neutrino scattering, are studied for momentum transfer values between 300 and 700 MeV/c. We have defined two indexes to have quantitative estimates of the scaling quality. We have analyzed experimental responses to get the empirical values of the two indexes. We have then investigated the effects of finite dimensions, collective excitations, meson exchange currents, short-range correlations and final state interactions. These effects strongly modify the relativistic Fermi gas scaling functions, but they conserve the scaling properties. We used the scaling functions to predict electron and neutrino cross sections and we tested their validity by comparing them with the cross sections obtained with a full calculation. For electron scattering we also made a comparison with data. We have calculated the total charge-exchange neutrino cross sections for neutrino energies up to 300 MeV.Comment: 19 pages, 12 figures, 1 table; to be published in Physical Review

    Mirizzi syndrome-differential diagnosis with cholangiocarcinoma: case report

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    Mirizzi syndrome is a rare complication of gallstone disease and poses a diagnostic challenge for general surgeons due to its clinical presentation, which resembles other pathological entities such as cholangiocarcinoma. We present a clinical case of a 68-year-old female patient with symptoms of jaundice and right upper quadrant pain. During the patient's diagnostic workup, altered liver function tests were documented, highlighting obstructive pattern hyperbilirubinemia, elevated tumor marker CA 19.9, and suspicion of biliary tract tumor based on imaging studies. However, surgical and pathological confirmation revealed Mirizzi syndrome. This case emphasizes the importance of considering differential diagnoses in patients presenting with obstructive jaundice to provide timely and appropriate treatment

    The finite range simple effective interaction including tensor terms

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    The prediction of single particle level crossing phenomenon between 2p3/22p_{3/2} and 1f5/21f_{5/2} orbitals in NiNi- and CuCu-isotopic chains by the finite range simple effective interaction without requiring the tensor part is discussed. In this case the experimentally observed crossing could be studied as a function of nuclear matter incompressibility, K(ρ0)K(\rho_0). The estimated crossing for the neutron number NN=46 could be reproduced by the equation of state corresponding to K(ρ0)K(\rho_0)=240 MeV. However, the observed proton gaps between the 1h11/21h_{11/2} and 1g7/21g_{7/2} shells in SnSn and SbSb isotopic chain, and the neutron gaps between the 1i13/21i_{13/2} and 1h9/21h_{9/2} shells in NN=82 isotones, as well as the shell closure properties at NN=28 require explicit consideration of a tensor part as the central contribution is not enough to initiate the required level splittings

    A model for two-proton emission induced by electron scattering

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    A model to study two-proton emission processes induced by electron scattering is developed. The process is induced by one-body electromagnetic operators acting together with short-range correlations, and by two-body Δ\Delta currents. The model includes all the diagrams containing a single correlation function. A test of the sensitivity of the model to the various theoretical inputs is done. An investigation of the relevance of the Δ\Delta currents is done by changing the final state angular momentum, excitation energy and momentum transfer. The sensitivity of the cross section to the details of the correlation function is studied by using realistic and schematic correlations. Results for 12^{12}C, 16^{16}O and 40^{40}Ca nuclei are presented.Comment: 30 pages, 18 figures, 3 table

    Reexamination of the N=50 and Z=28 shell closure

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    Recent experiments performed in neutron-rich copper isotopes have revealed a crossing in the nucleus 75Cu between the 3/2− and 5/2− levels, which correspond to the ground state and the first excited state in isotopes with mass number below =75. Due to the strong single-particle character of these states, this scenario can be investigated through the analysis of the proton spectrum provided by mean-field models in nickel isotopes with neutron numbers between =40 and =50. In this work, we show that the aforementioned crossing is mainly driven by the mean field provided by the effective nucleon-nucleon and spin-orbit interactions. We also analyze the impact of the tensor interaction and find that in some mean-field models it is essential to reproduce the crossing of the 2⁢3/2 and 1⁢5/2 proton single-particle levels, as in the case of the SAMi-T Skyrme force and the D1M Gogny interaction, whereas in other cases, as for example the SLy5 Skyrme force, a reasonable tensor force appears to be unable to modify the mean-field enough to reproduce this level crossing. Finally, in the calculations performed with the so-called simple effective interaction (SEI), it is shown that the experimental data in nickel and copper isotopes considered in this work can be explained satisfactorily without any explicit consideration of the tensor interaction

    Early response competition over the motor cortex underlies proactive control of error correction

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    Response inhibition is a fundamental brain function that must be flexible enough to incorporate proactive goal-directed demands, along with reactive, automatic and well consolidated behaviors. However, whether proactive inhibitory processes can be explained by response competition, rather than by active top-down inhibitory control, remains still unclear. Using a modified version of the Eriksen flanker task, we examined the behavioral and electrophysiological correlates elicited by manipulating the degree of inhibitory control in a task that involved the fast amendment of errors. We observed that restraining or encouraging the correction of errors did not affect the behavioral and neural correlates associated to reactive inhibition. We rather found that an early, sustained and bilateral activation, of both the correct and the incorrect response, was required for an effective proactive inhibitory control. Selective unilateral patterns of response preparation were instead associated with defective response suppression. Our results provide behavioral and electrophysiological evidence of a simultaneous dual pre-activation of two motor commands, likely underlying a global operating mechanism suggesting competition or lateral inhibition to govern the amendment of errors. These findings are consistent with the response inhibitory processes already observed in speed accuracy tradeoff studies, and hint at a decisive role of early response competition to determine the success of multiple-choice action selection
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