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101.
Alessia Antelmi Gennaro Cordasco Carmine Spagnuolo Przemysaw Szufel 《Entropy (Basel, Switzerland)》2021,23(7)
This work deals with a generalization of the minimum Target Set Selection (TSS) problem, a key algorithmic question in information diffusion research due to its potential commercial value. Firstly proposed by Kempe et al., the TSS problem is based on a linear threshold diffusion model defined on an input graph with node thresholds, quantifying the hardness to influence each node. The goal is to find the smaller set of items that can influence the whole network according to the diffusion model defined. This study generalizes the TSS problem on networks characterized by many-to-many relationships modeled via hypergraphs. Specifically, we introduce a linear threshold diffusion process on such structures, which evolves as follows. Let be a hypergraph. At the beginning of the process, the nodes in a given set are influenced. Then, at each iteration, (i) the influenced hyperedges set is augmented by all edges having a sufficiently large number of influenced nodes; (ii) consequently, the set of influenced nodes is enlarged by all the nodes having a sufficiently large number of already influenced hyperedges. The process ends when no new nodes can be influenced. Exploiting this diffusion model, we define the minimum Target Set Selection problem on hypergraphs (TSSH). Being the problem NP-hard (as it generalizes the TSS problem), we introduce four heuristics and provide an extensive evaluation on real-world networks. 相似文献
102.
Paul W. Goldberg Rahul Savani Troels Bjerre Sørensen Carmine Ventre 《International Journal of Game Theory》2013,42(4):1059-1083
We study the performance of Fictitious Play (FP), when used as a heuristic for finding an approximate Nash equilibrium of a two-player game. We exhibit a class of two-player games having payoffs in the range $[0,1]$ that show that FP fails to find a solution having an additive approximation guarantee significantly better than $1/2$ . Our construction shows that for $n\times n$ games, in the worst case both players may perpetually have mixed strategies whose payoffs fall short of the best response by an additive quantity $1/2 - O(1/n^{1-\delta })$ for arbitrarily small $\delta $ . We also show an essentially matching upper bound of $1/2 - O(1/n)$ . 相似文献
103.
Jianwei Wang Anton GeilerPerhaad Mistry David R. Kaeli Vincent G. Harris Carmine Vittoria 《Journal of magnetism and magnetic materials》2012,324(6):991-994
Theoretical models were developed to design self-biased Y-junction circulators operating at ultra high frequency (UHF). The proposed circulator designs consist of insulating nanowires of yttrium iron garnet (YIG) embedded in high permittivity barium-strontium titanate (BSTO) substrates. A design with as many as 105 or greater wires may be considered in its entirety to determine the electromagnetic scattering S-parameters of a circulator design, thus helping to mitigate the computational limitations of the available finite element method (FEM) tools. The approach seeks to represent the nanowires and the BSTO substrate by an equivalent medium with effective properties inclusive of the average saturation magnetization, dynamic demagnetizing fields, and permittivity. The effective medium approach was validated in comparison with the FEM models. Using the proposed approach, a self-biased junction circulator consisting of YIG nanowires embedded in a BSTO substrate was designed and simulated in which the center frequency insertion loss was calculated to be as low as 0.16 dB with isolation of −42.3 dB at 1 GHz. The 20 dB bandwidth was calculated to be 50 MHz. These results suggest that practical self-biased circulators at the UHF band are feasible. 相似文献
104.
Directional calixarene wheels were threaded along a bis(benzylalkylammonium) axle in a stereoprogrammed way to obtain the first examples of calixarene-based [3]rotaxanes. The base/acid treatment demonstrated that these systems act as nanosized molecular shuttles. An unprecedented switching between the tail-to-tail and head-to-head relative orientation of the calix-wheels was observed. 相似文献
105.
106.
Vincent G. Harris Anton Geiler Yajie Chen Mingzhong Wu Zhaohui Chen Peng He Patanjali V. Parimi Xu Zuo Manasori Abe Carmine Vittoria 《Journal of magnetism and magnetic materials》2009,321(14):2035-2047
Next generation magnetic microwave devices will be planar, smaller, weigh less, and perform well beyond the present state-of-the-art. For this to become a reality advances in ferrite materials must first be realized. These advances include self-bias magnetization, tunability of the magnetic anisotropy, low microwave loss, and volumetric and weight reduction. To achieve these goals one must turn to novel materials processing methods. Here, we review recent advances in the processing of microwave ferrites. Attention is paid to the processing of ferrite films by pulsed laser deposition, liquid phase epitaxy, spin spray ferrite plating, screen printing, and compaction of quasi-single crystals. Conventional and novel applications of ferrite materials, including microwave non-reciprocal passive devices, microwave signal processing, negative index metamaterial-based electronics, and electromagnetic interference suppression are discussed. 相似文献
107.
Valentina Lo Giudice Immacolata Faraone Maria Roberta Bruno Maria Ponticelli Fabiana Labanca Donatella Bisaccia Carmine Massarelli Luigi Milella Luigi Todaro 《Molecules (Basel, Switzerland)》2021,26(16)
The need to produce an ever-increasing quantity of material products and food resulting from the planet globalization process has contributed to the spread of modern agriculture based on a linear production resulting in the generation of tons of waste. This huge amount of waste is generally accumulated in landfills, causing different environmental problems. Hence, researchers moved on to study the processes used to recover agro-industrial by-products within a circular and sustainable bio-economy concept. A systematic quest on Scopus and PubMed databases was performed to identify the data available to date on recycling agro-industrial by-products of Olea europaea L. This systematic review summarizes the knowledge regarding the use of olive trees by-products for producing animal feed, biocomposites, bioethanol, cellulose pulp, activated carbon, and as a fuel source for energy production. Furthermore, the data regarding the potential biological activity of extracts from olive roots, wood, bark, and pruning were analyzed. Olive trees by-products are, indeed, rich in molecules with antioxidant, antimicrobial, cardioprotective, and anticancer activity, representing a promising candidate for treat several human diseases. 相似文献
108.
We discuss the quantum phase transitions (QPT) in N-spin chains from the point of view of collective observables. We show that the measurement space representation is a convenient tool for the analysis of phase transitions, allowing the determination of an appropriate set of macroscopic order parameters (for a given Hamiltonian). Quantum correlations in the vicinity of the critical points are analyzed both in the ground states and low temperature thermal states. 相似文献
109.
We investigate numerically and experimentally the spatial collapse dynamics and polarization stability of radially and azimuthally polarized vortex beams in pure Kerr medium. These beams are unstable to azimuthal modulation instabilities and break up into distinct collapsing filaments. The polarization of the filaments is primarily linear with weak circular components at the filaments' boundaries. This unique hybrid linear-circular polarization collapse pattern persists to advanced stages of collapse and appears to be a general feature of beams with spatially variant linear polarization. 相似文献
110.
Margherita De Rosa Stefania Gambaro Annunziata Soriente Paolo Della Sala Veronica Iuliano Carmen Talotta Carmine Gaeta Antonio Rescifina Placido Neri 《Chemical science》2022,13(29):8618
Carbocation catalysis can be performed inside the confined space of the hexameric resorcinarene capsule. The inner cavity of the capsule can host the trityl carbocation, which catalyses the Diels–Alder reaction between dienes and unsaturated aldehydes. Experimental results and in silico calculations show that the hexameric resorcinarene capsule C6 can promote the formation of the trityl carbocation from trityl chloride through the cleavage of the carbon–halogen bond promoted by OH⋯X− hydrogen bonding. Here it is shown that the combination of the nanoconfined space and the latent carbocation catalysis provides a convenient complementary strategy for the typical carbocation catalysis. The latent strategy bypasses the typical pitfalls associated with active carbocations and provides control of the reaction efficiency in terms of reaction rate, conversion, and selectivity.The hexameric resorcinarene capsule is able to promote carbocation catalysis inside its cavity. 相似文献