31,527 research outputs found

    Caching and Auditing in the RPPM Model

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    Crampton and Sellwood recently introduced a variant of relationship-based access control based on the concepts of relationships, paths and principal matching, to which we will refer as the RPPM model. In this paper, we show that the RPPM model can be extended to provide support for caching of authorization decisions and enforcement of separation of duty policies. We show that these extensions are natural and powerful. Indeed, caching provides far greater advantages in RPPM than it does in most other access control models and we are able to support a wide range of separation of duty policies.Comment: Accepted for publication at STM 2014 (without proofs, which are included in this longer version

    Bridgeness: A Local Index on Edge Significance in Maintaining Global Connectivity

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    Edges in a network can be divided into two kinds according to their different roles: some enhance the locality like the ones inside a cluster while others contribute to the global connectivity like the ones connecting two clusters. A recent study by Onnela et al uncovered the weak ties effects in mobile communication. In this article, we provide complementary results on document networks, that is, the edges connecting less similar nodes in content are more significant in maintaining the global connectivity. We propose an index named bridgeness to quantify the edge significance in maintaining connectivity, which only depends on local information of network topology. We compare the bridgeness with content similarity and some other structural indices according to an edge percolation process. Experimental results on document networks show that the bridgeness outperforms content similarity in characterizing the edge significance. Furthermore, extensive numerical results on disparate networks indicate that the bridgeness is also better than some well-known indices on edge significance, including the Jaccard coefficient, degree product and betweenness centrality.Comment: 10 pages, 4 figures, 1 tabl

    Effect of user tastes on personalized recommendation

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    In this paper, based on a weighted projection of the user-object bipartite network, we study the effects of user tastes on the mass-diffusion-based personalized recommendation algorithm, where a user's tastes or interests are defined by the average degree of the objects he has collected. We argue that the initial recommendation power located on the objects should be determined by both of their degree and the users' tastes. By introducing a tunable parameter, the user taste effects on the configuration of initial recommendation power distribution are investigated. The numerical results indicate that the presented algorithm could improve the accuracy, measured by the average ranking score, more importantly, we find that when the data is sparse, the algorithm should give more recommendation power to the objects whose degrees are close to the users' tastes, while when the data becomes dense, it should assign more power on the objects whose degrees are significantly different from user's tastes.Comment: 8 pages, 4 figure

    A novel online data-driven algorithm for detecting UAV navigation sensor faults

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    The use of Unmanned Aerial Vehicles (UAVs) has increased significantly in recent years. On-board integrated navigation sensors are a key component of UAVs' flight control systems and are essential for flight safety. In order to ensure flight safety, timely and effective navigation sensor fault detection capability is required. In this paper, a novel data-driven Adaptive Neuron Fuzzy Inference System (ANFIS)-based approach is presented for the detection of on-board navigation sensor faults in UAVs. Contrary to the classic UAV sensor fault detection algorithms, based on predefined or modelled faults, the proposed algorithm combines an online data training mechanism with the ANFIS-based decision system. The main advantages of this algorithm are that it allows real-time model-free residual analysis from Kalman Filter (KF) estimates and the ANFIS to build a reliable fault detection system. In addition, it allows fast and accurate detection of faults, which makes it suitable for real-time applications. Experimental results have demonstrated the effectiveness of the proposed fault detection method in terms of accuracy and misdetection rate

    Crystal growth and magnetic structure of MnBi2Te4

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    Millimeter-sized MnBi2_2Te4_4 single crystals are grown out of Bi-Te flux and characterized by measuring magnetic and transport properties, scanning tunneling microscope (STM) and spectroscopy (STS). The magnetic structure of MnBi2_2Te4_4 below TN_N is determined by powder and single crystal neutron diffraction measurements. Below TN_N=24\,K, Mn2+^{2+} moments order ferromagnetically in the \textit{ab} plane but antiferromagnetically along the crystallographic \textit{c} axis. The ordered moment is 4.04(13) μB\mu_{B}/Mn at 10\,K and aligned along the crystallographic \textit{c}-axis. The electrical resistivity drops upon cooling across TN_N or when going across the metamagnetic transition in increasing fields below TN_N. A critical scattering effect was observed in the vicinity of TN_N in the temperature dependence of thermal conductivity. However, A linear temperature dependence was observed for thermopower in the temperature range 2K-300K without any anomaly around TN_N. These indicate that the magnetic order in Mn-Te layer has negligible effect on the electronic band structure, which makes possible the realization of proposed topological properties in MnBi2_2Te4_4 after fine tuning of the electronic band structure

    Study of Radiative Leptonic D Meson Decays

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    We study the radiative leptonic DD meson decays of D^+_{(s)}\to \l^+\nu_{\l}\gamma (\l=e,\mu,\tau), D0→ννˉγD^0\to \nu\bar{\nu}\gamma and D^0\to \l^+\l^-\gamma (l=e,μl=e,\mu) within the light front quark model. In the standard model, we find that the decay branching ratios of D(s)+→e+νeγD^+_{(s)}\to e^+\nu_e\gamma, D(s)+→μ+νμγD^+_{(s)}\to\mu^+\nu_{\mu}\gamma and D(s)+→τ+ντγD^+_{(s)}\to\tau^+\nu_{\tau}\gamma are 6.9×10−66.9\times 10^{-6} (7.7×10−57.7\times 10^{-5}), 2.5×10−52.5\times 10^{-5} (2.6×10−42.6\times 10^{-4}), and 6.0×10−66.0\times 10^{-6} (3.2×10−43.2\times 10^{-4}), and that of D^0\to\l^+\l^-\gamma (\l=e,\mu) and D0→ννˉγD^0\to\nu\bar{\nu}\gamma are 6.3×10−116.3\times 10^{-11} and 2.7×10−162.7\times 10^{-16}, respectively.Comment: 23 pages, 6 Figures, LaTex file, a reference added, to be published in Mod. Phys. Lett.

    Cross-Task Transfer for Geotagged Audiovisual Aerial Scene Recognition

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    Aerial scene recognition is a fundamental task in remote sensing and has recently received increased interest. While the visual information from overhead images with powerful models and efficient algorithms yields considerable performance on scene recognition, it still suffers from the variation of ground objects, lighting conditions etc. Inspired by the multi-channel perception theory in cognition science, in this paper, for improving the performance on the aerial scene recognition, we explore a novel audiovisual aerial scene recognition task using both images and sounds as input. Based on an observation that some specific sound events are more likely to be heard at a given geographic location, we propose to exploit the knowledge from the sound events to improve the performance on the aerial scene recognition. For this purpose, we have constructed a new dataset named AuDio Visual Aerial sceNe reCognition datasEt (ADVANCE). With the help of this dataset, we evaluate three proposed approaches for transferring the sound event knowledge to the aerial scene recognition task in a multimodal learning framework, and show the benefit of exploiting the audio information for the aerial scene recognition. The source code is publicly available for reproducibility purposes.Comment: ECCV 202

    Anatomical features of the radial artery in the Xinjiang population in China and its impact on the transradial coronary intervention procedure

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    Background: The anatomical features of the radial artery (RA) influence the transradial coronary intervention. The aim of this study is to discuss the anatomical features of the RA in the Xinjiang population and to guide interventionists in decreasing complications and improving success rates. Materials and methods: We enrolled 1731 patients in this study. All relevant basic information was recorded in detail, and the RA diameter was examined. Patients were divided into a RA variation group and a RA non-variation group; univariate and multivariate factor analyses were performed to evaluate the relevant factors for RA diameter and the predictive value of the variable factors in RA variations. Results: The mean RA diameter for all patients was 3.01 ± 0.14 mm. The multi-factorial analysis showed that height, gender, and occupation are significantly associated with RA diameter (p < 0.05). The incidence of RA variation was 4.97% (86/1731). Multi-factorial analysis showed that: gender (OR 2.72, 95% CI 1.469–5.037, p < 0.01), occupation (OR 2.228, 95% CI 1.0.000–0.012, p < 0.001) and RA inner diameter (OR 0.002, 95% CI 0.000–0.012, p < 0.001) are significantly associated with the incidence of RA variation. Conclusions: The mean RA diameter in the Xinjiang population was 3.01 ± 0.14 mm, height, gender, occupation are associated with RA diameter, gender, farmer, RA diameter are associated with RA variation. These factors can guide the interventionists to choose the appropriate equipment before the operation then can increase the efficiency of operation and prevent from the complications

    A review of process advancement of novel metal spinning

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    Metal spinning technology has seen a rapid development in recent years. Novel spinning processes, such as non-axisymmetrical spinning, non-circular cross-section spinning and tooth-shaped spinning, are being developed. This has challenged the limitation of traditional spinning technology being used for manufacturing axisymmetrical, circular cross-section, and uniform wall-thickness parts. In this paper, the classification of the traditional spinning processes is proposed based on the material deformation characteristics, the relative position between roller and blank, mandrel spinning and mandrel-free spinning, and temperature of the blank during spinning. The advancement of recently developed novel spinning processes and corresponding tool design and equipment development are reviewed. The classification of the novel spinning processes is proposed based on the relative position between the rotating axes, the geometry of cross-section and the variation of wall-thickness of the spun parts. The material deformation mechanism, processing failures and spun part defects of the aforementioned three groups of novel spinning processes are discussed by analyzing four representative spinning processes of industrial applications. Furthermore, other novel spinning processes and their classification as reported in the literature are summarized
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