584 research outputs found

    Incremental Learning Method for Data with Delayed Labels

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    Most research on machine learning tasks relies on the availability of true labels immediately after making a prediction. However, in many cases, the ground truth labels become available with a non-negligible delay. In general, delayed labels create two problems. First, labelled data is insufficient because the label for each data chunk will be obtained multiple times. Second, there remains a problem of concept drift due to the long period of data. In this work, we propose a novel incremental ensemble learning when delayed labels occur. First, we build a sliding time window to preserve the historical data. Then we train an adaptive classifier by labelled data in the sliding time window. It is worth noting that we improve the TrAdaBoost to expand the data of the latest moment when building an adaptive classifier. It can correctly distinguish the wrong types of source domain sample classification. Finally, we integrate the various classifiers to make predictions. We apply our algorithms to synthetic and real credit scoring datasets. The experiment results indicate our algorithms have superiority in delayed labelling setting

    The Impact of Power on Information Sharing in E-Government

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    In the digital era, information sharing is of utter importance to improving the quality and benefits of government services. At present, there is a lot of information housed by and distributed among different government agencies, which poses significant challenges and barriers to information sharing and dissemination. This paper presents a research model that examines some crucial factors, including administrative power, trust, perceived risk, and power games, that may affect information sharing in e-Government. The administrative power can be classified as coercive power and coordinated power. Trust, perceived risk, and power games are introduced as moderators of the power on information sharing in the research model. Results of our empirical study indicate that coercive power and coordinated power positively affect information sharing, and such effects are moderated by trust among employees and power ames. The research and practical implications of this tudy are also discussed

    Magnetic band representations, Fu-Kane-like symmetry indicators and magnetic topological materials

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    To realize novel topological phases and to pursue potential applications in low-energy consumption spintronics, the study of magnetic topological materials is of great interest. Starting from the theory of nonmagnetic topological quantum chemistry [Bradlyn et al., Nature 547, 298 (2017)], we have obtained irreducible (co)representations and compatibility relations (CRs) in momentum space, and we constructed a complete list of magnetic band (co)representations (MBRs) in real space for other MSGs with anti-unitary symmetries (i.e. type-III and type-IV MSGs). The results are consistent with the magnetic topological quantum chemistry [Elcoro et al., Nat. Comm. 12, 5965 (2021)]. Using the CRs and MBRs, we reproduce the symmetry-based classifications for MSGs, and we obtain a set of Fu-Kane-like formulas of symmetry indicators (SIs) in both spinless (bosonic) and spinful (fermionic) systems, which are implemented in an automatic code - TopMat - to diagnose topological magnetic materials. The magnetic topological materials, whose occupied states can not be decomposed into a sum of MBRs, are consistent with nonzero SIs. Lastly, using our online code, we have performed spin-polarized calculations for magnetic compounds in the materials database and find many magnetic topological candidates.Comment: 6 pages, 3128 pages for the Appendice

    PO-087 4-weeks hypoxia (HHL) training improves rowers’ cutaneous microcirculation

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    Objective Sport scientists always pay attention to cardiorespiratory and hematologic system on benefit of hypoxic training, but peripheral circulation may be one of these benefit, which is one cause of improving performance. So, in order to know whether or not hypoxic training affect athletes’ cutaneous microcirculation, we test rowers’ microcirculation for 4 weeks’ High Live-High Train-Low exercise(HHL). Methods The subject is 21 male rowers of Shanghai rowing team.12 of them take part in 4 weeks HHL (train and live at 2500m, exercise at 100m), while 9 of them train in normoxia. Forearm and leg cutaneous blood flow(CBF) was measured using a laser doppler flowmeter (PeriFlux600, Perimed, Sweden) at room temperature (22℃) with subject lying position and after testing in that position for at least 10min. We tested the forearm and leg blood flow, and also the blood flow when localized heating to 44℃ for 3 mins. Microvascular reactivity(MVR) was evaluated form the maximal post occlusive reactive hyperemia(PORH) following 3-min forearm ischemia produced by cuff inflation (200mm Hg). Similar procedures have been used by other investigators. Blood pressure was measured by brachial auscultation. SPO2 and heart rate was measured by a hand hold pulse oximeter (NONIN, 9500, USA) .The blood flow was measured 4 times, baseline, 1stweek, 3rdweek and post. Results Blood flow and CMBC of forearm of HHL increased significantly at 1stweek(8.9,13.0;112.0,151.0,P<0.05), but thigh and NOM group did not increase. The lowest and highest blood flow of PORH both increase at 1stweek(2,9,3.2;46.0,53.0;0.05<P<0.1). At 3rdweek, HHL group’s resting blood flow and CMBC of forearm is lower than 1stweek(9.3,13.0;124.5,151.0), but higher than pretraining, but velocity of blood flow decreased(8.2,9.2).  These results suggest at early stage of HHL, vasoconstriction may be dominant. But when rowers suffer more and more hypoxia, vasodilation and angiogenesis may play a key role in their skin blood flow. At 3rdweek after training, the blood flow and CMBC are similar with baseline. Conclusions 4 weeks HHL training of rowers increase forearm blood flow, but no thigh. This is because thigh is main working muscle of rowers, which may be affected by training status and fatigue. And also, PORH reserve capacity is an indicator of endothelial function. In this study, we find HHL rowers increase their PORH reserve capacity, which means endothelial function is improved by hypoxia training. So, besides the traditional research of Hematologic System on hypoxia training, we find 4 weeks HHL training increase forearm blood flow and improve endothelial function. This may be one mechanism of improving performance, which need more studies to confirm

    Application of local singularity in prospecting potential oil/gas Targets

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    International audienceTogether with generalized self-similarity and the fractal spectrum, local singularity analysis has been introduced as one part of the new 3S principle and technique for mineral resource assessment based on multifractal modeling, which has been demonstrated to be useful for anomaly delineation. Local singularity is used in this paper to characterize the property of multifractal distribution patterns of geochemical indexes to delineate potential areas for oil/gas exploration using the advanced GeoDAS GIS technology. Geochemical data of four oil/gas indexes, consisting of acid-extracted methane (SC1), ethane (SC2), propane (SC3), and secondary carbonate (?C), from 9637 soil samples amassed within a large area of 11.2×104 km2 in the Songpan-Aba district, Sichuan Province, southwestern China, were analyzed. By eliminating the interference of geochemical oil/gas data with the method of media-modification and Kriging, the prospecting area defined by the local singularity model is better identified and the results show that the subareas with higher singularity exponents for the four oil/gas indexes are potential targets for oil/gas exploration. These areas in the shape of rings or half-rings are spatially associated with the location of the known producing drilling well in this area. The spatial relationship between the anomalies delineated by oil/gas geochemical data and distribution patterns of local singularity exponents is confirmed by using the stable isotope of ?13C

    1,4-Bis[3-chloro-2-(chloro­meth­yl)prop­yl]benzene

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    The title mol­ecule, C14H18Cl4, possesses a crystallographically imposed inversion centre, which coincides with the centre of benzene ring. In the absence of classical inter­molecular inter­actions, van der Waals forces help the mol­ecules to pack in the crystal
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