25,245 research outputs found

    Time-and event-driven communication process for networked control systems: A survey

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    Copyright © 2014 Lei Zou et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.In recent years, theoretical and practical research topics on networked control systems (NCSs) have gained an increasing interest from many researchers in a variety of disciplines owing to the extensive applications of NCSs in practice. In particular, an urgent need has arisen to understand the effects of communication processes on system performances. Sampling and protocol are two fundamental aspects of a communication process which have attracted a great deal of research attention. Most research focus has been on the analysis and control of dynamical behaviors under certain sampling procedures and communication protocols. In this paper, we aim to survey some recent advances on the analysis and synthesis issues of NCSs with different sampling procedures (time-and event-driven sampling) and protocols (static and dynamic protocols). First, these sampling procedures and protocols are introduced in detail according to their engineering backgrounds as well as dynamic natures. Then, the developments of the stabilization, control, and filtering problems are systematically reviewed and discussed in great detail. Finally, we conclude the paper by outlining future research challenges for analysis and synthesis problems of NCSs with different communication processes.This work was supported in part by the National Natural Science Foundation of China under Grants 61329301, 61374127, and 61374010, the Royal Society of the UK, and the Alexander von Humboldt Foundation of Germany

    A rapid cosmic-ray increase in BC 3372-3371 from ancient buried tree rings in China

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    Cosmic rays interact with the Earth's atmosphere to produce 14^{14}C, which can be absorbed by trees. Therefore, rapid increases of 14^{14}C in tree rings can be used to probe previous cosmic-ray events. By this method, three 14^{14}C rapidly increasing events have been found. Plausible causes of these events include large solar proton events, supernovae or short gamma-ray bursts. However, due to the lack of measurements of 14^{14}C by year, the occurrence frequency of such 14^{14}C rapidly increasing events is poorly known. In addition, rapid increases may be hidden in the IntCal13 data with five-year resolution. Here we report the result of 14^{14}C measurements using an ancient buried tree during the period between BC 3388 and 3358. We find a rapid increase of about 9\textperthousand~ in the 14^{14}C content from BC 3372 to BC 3371. We suggest that this event could originate from a large solar proton event.Comment: 23 pages, 3 figures, 2 tables, published in Nature Communication

    Intelectin contributes to allergen-induced IL-25, IL-33, and TSLP expression and type 2 response in asthma and atopic dermatitis.

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    The epithelial and epidermal innate cytokines IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) have pivotal roles in the initiation of allergic inflammation in asthma and atopic dermatitis (AD). However, the mechanism by which the expression of these innate cytokines is regulated remains unclear. Intelectin (ITLN) is expressed in airway epithelial cells and promotes allergic airway inflammation. We hypothesized that ITLN is required for allergen-induced IL-25, IL-33, and TSLP expression. In two asthma models, Itln knockdown reduced allergen-induced increases in Il-25, Il-33, and Tslp and development of type 2 response, eosinophilic inflammation, mucus overproduction, and airway hyperresponsiveness. Itln knockdown also inhibited house dust mite (HDM)-induced early upregulation of Il-25, Il-33, and Tslp in a model solely inducing airway sensitization. Using human airway epithelial cells, we demonstrated that HDM-induced increases in ITLN led to phosphorylation of epidermal growth factor receptor and extracellular-signal regulated kinase, which were required for induction of IL-25, IL-33, and TSLP expression. In two AD models, Itln knockdown suppressed expression of Il-33, Tslp, and Th2 cytokines and eosinophilic inflammation. In humans, ITLN1 expression was significantly increased in asthmatic airways and in lesional skin of AD. We conclude that ITLN contributes to allergen-induced Il-25, Il-33, and Tslp expression in asthma and AD

    Electronic States and Magnetism of Mn Impurities and Dimers in Narrow-Gap and Wide-Gap III-V Semiconductors

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    Electronic states and magnetic properties of single MnMn impurity and dimer doped in narrow-gap and wide-gap IIIIII-VV semiconductors have been studied systematically. It has been found that in the ground state for single MnMn impurity, MnMn-As(N)As(N) complex is antiferromagnetic (AFM) coupling when pp-dd hybridization VpdV_{pd} is large and both the hole level EvE_{v} and the impurity level EdE_{d} are close to the midgap; or very weak ferromagnetic (FM) when VpdV_{pd} is small and both EvE_{v} and EdE_d are deep in the valence band. In MnMn dimer situation, the MnMn spins are AFM coupling for half-filled or full-filled pp orbits; on the contrast, the Mn spins are double-exchange-like FM coupling for any pp-orbits away from half-filling. We propose the strong {\it p-d} hybridized double exchange mechanism is responsible for the FM order in diluted IIIIII-VV semiconductors

    Spin correlated interferometry for polarized and unpolarized photons on a beam splitter

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    Spin interferometry of the 4th order for independent polarized as well as unpolarized photons arriving simultaneously at a beam splitter and exhibiting spin correlation while leaving it, is formulated and discussed in the quantum approach. Beam splitter is recognized as a source of genuine singlet photon states. Also, typical nonclassical beating between photons taking part in the interference of the 4th order is given a polarization dependent explanation.Comment: RevTeX, 19 pages, 1 ps figure, author web page at http://m3k.grad.hr/pavici

    Graph Domain Adaptation for Alignment-Invariant Brain Surface Segmentation

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    The varying cortical geometry of the brain creates numerous challenges for its analysis. Recent developments have enabled learning surface data directly across multiple brain surfaces via graph convolutions on cortical data. However, current graph learning algorithms do fail when brain surface data are misaligned across subjects, thereby affecting their ability to deal with data from multiple domains. Adversarial training is widely used for domain adaptation to improve the segmentation performance across domains. In this paper, adversarial training is exploited to learn surface data across inconsistent graph alignments. This novel approach comprises a segmentator that uses a set of graph convolution layers to enable parcellation directly across brain surfaces in a source domain, and a discriminator that predicts a graph domain from segmentations. More precisely, the proposed adversarial network learns to generalize a parcellation across both, source and target domains. We demonstrate an 8% mean improvement in performance over a non-adversarial training strategy applied on multiple target domains extracted from MindBoggle, the largest publicly available manually-labeled brain surface dataset

    Fabrication and superconductivity of NaxTaS2 crystals

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    In this paper we report the growth and superconductivity of NaxTaS2Na_xTaS_2 crystals. The structural data deduced from X-ray diffraction pattern shows that the sample has the same structure as 2HTaS22H-TaS_2. A series of crystals with different superconducting transition temperatures (TcT_c) ranging from 2.5 K to 4.4 K were obtained. It is found that the TcT_c rises with the increase of NaNa content determined by Energy-Dispersive x-ray microanalysis(EDX) of Scanning Electron Microscope (SEM) on these crystals. Compared with the resistivity curve of un-intercalated sample 2HTaS22H-TaS_2 (TcT_c = 0.8 K, TCDWT_{CDW} \approx 70 K), no signal of charge density wave (CDW) was observed in samples Na0.1TaS2Na_{0.1}TaS_2 and Na0.05TaS2Na_{0.05}TaS_2. However, in some samples with lower TcT_c, the CDW appears again at about 65 K. Comparison between the anisotropic resistivity indicates that the anisotropy becomes smaller in samples with more NaNa intercalation (albeit a weak semiconducting behavior along c-axis) and thus higher TcT_c. It is thus concluded that there is a competition between the superconductivity and the CDW. With the increase of sodium content, the rise of TcT_c in NaxTaS2Na_xTaS_2 is caused mainly by the suppression to the CDW in 2HTaS22H-TaS_2, and the conventional rigid band model for layered dichalcogenide may be inadequate to explain the changes induced by the slight intercalation of sodium in 2HTaS22H-TaS_2.Comment: 8 pages, 13 figures, To appear in Physical Review
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