1,978 research outputs found

    (2 +1)-dimensional Duffin-Kemmer-Petiau oscillator under a magnetic field in the presence of a minimal length in the noncommutative space

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    Using the momentum space representation, we study the (2 +1)-dimensional Duffin-Kemmer-Petiau oscillator for spin 0 particle under a magnetic field in the presence of a minimal length in the noncommutative space. The explicit form of energy eigenvalues are found, the wave functions and the corresponding probability density are reported in terms of the Jacobi polynomials. Additionally, we also discuss the special cases and depict the corresponding numerical results

    Design of Two-Level Incentive Mechanisms for Hierarchical Federated Learning

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    Hierarchical Federated Learning (HFL) is a distributed machine learning paradigm tailored for multi-tiered computation architectures, which supports massive access of devices' models simultaneously. To enable efficient HFL, it is crucial to design suitable incentive mechanisms to ensure that devices actively participate in local training. However, there are few studies on incentive mechanism design for HFL. In this paper, we design two-level incentive mechanisms for the HFL with a two-tiered computing structure to encourage the participation of entities in each tier in the HFL training. In the lower-level game, we propose a coalition formation game to joint optimize the edge association and bandwidth allocation problem, and obtain efficient coalition partitions by the proposed preference rule, which can be proven to be stable by exact potential game. In the upper-level game, we design the Stackelberg game algorithm, which not only determines the optimal number of edge aggregations for edge servers to maximize their utility, but also optimize the unit reward provided for the edge aggregation performance to ensure the interests of cloud servers. Furthermore, numerical results indicate that the proposed algorithms can achieve better performance than the benchmark schemes

    Discovery of six high-redshift quasars with the Lijiang 2.4m telescope and the Multiple Mirror Telescope

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    Quasars with redshifts greater than 4 are rare, and can be used to probe the structure and evolution of the early universe. Here we report the discovery of six new quasars with ii-band magnitudes brighter than 19.5 and redshifts between 2.4 and 4.6 from the YFOSC spectroscopy of the Lijiang 2.4m telescope in February, 2012. These quasars are in the list of z>3.6z>3.6 quasar candidates selected by using our proposed J−K/i−YJ-K/i-Y criterion and the photometric redshift estimations from the SDSS optical and UKIDSS near-IR photometric data. Nine candidates were observed by YFOSC, and five among six new quasars were identified as z>3.6z>3.6 quasars. One of the other three objects was identified as a star and the other two were unidentified due to the lower signal-to-noise ratio of their spectra. This is the first time that z>4z>4 quasars have been discovered using a telescope in China. Thanks to the Chinese Telescope Access Program (TAP), the redshift of 4.6 for one of these quasars was confirmed by the Multiple Mirror Telescope (MMT) Red Channel spectroscopy. The continuum and emission line properties of these six quasars, as well as their central black hole masses and Eddington ratios, were obtained.Comment: 7 pages, 2 figures, published in Research in Astronomy and Astrophysics (RAA) as a lette

    Clinical assessment of 252Californium neutron intracavitary brachytherapy using a two-channel Y applicator combined with external beam radiotherapy for endometrial cancer

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    OBJECTIVE: The aim of this study was to determine the efficacy of 252Californium neutron intracavitary brachytherapy using a two-channel Y applicator combined with external beam radiotherapy for the treatment of endometrial cancer. METHODS: Thirty-one patients with stage I-III endometrial cancer were recruited for this study. The stage I patients received only 252Californium neutron intracavitary brachytherapy with a two-channel applicator. The stage II and III patients received both 252Californium neutron intracavitary brachytherapy using a two-channel applicator and parallel-opposed whole pelvic radiotherapy. RESULTS: The five-year local control rate was 80.6% (25/31), the overall survival rate was 51.6% (16/31), and the disease-free survival rate was 54.8% (17/31). The incidence of serious late complications was 12.9% (4/31). CONCLUSIONS: 252Californium neutron intracavitary brachytherapy using a two-channel applicator combined with external beam radiotherapy was effective for treating endometrial cancer and the incidence of serious late complications related to this combination was within an acceptable range
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