4,011 research outputs found

    Rotation-invariant features for multi-oriented text detection in natural images.

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    Texts in natural scenes carry rich semantic information, which can be used to assist a wide range of applications, such as object recognition, image/video retrieval, mapping/navigation, and human computer interaction. However, most existing systems are designed to detect and recognize horizontal (or near-horizontal) texts. Due to the increasing popularity of mobile-computing devices and applications, detecting texts of varying orientations from natural images under less controlled conditions has become an important but challenging task. In this paper, we propose a new algorithm to detect texts of varying orientations. Our algorithm is based on a two-level classification scheme and two sets of features specially designed for capturing the intrinsic characteristics of texts. To better evaluate the proposed method and compare it with the competing algorithms, we generate a comprehensive dataset with various types of texts in diverse real-world scenes. We also propose a new evaluation protocol, which is more suitable for benchmarking algorithms for detecting texts in varying orientations. Experiments on benchmark datasets demonstrate that our system compares favorably with the state-of-the-art algorithms when handling horizontal texts and achieves significantly enhanced performance on variant texts in complex natural scenes

    String order and hidden topological symmetry in the SO(2n+1) symmetric matrix product states

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    We have introduced a class of exactly soluble Hamiltonian with either SO(2n+1) or SU(2) symmetry, whose ground states are the SO(2n+1) symmetric matrix product states. The hidden topological order in these states can be fully identified and characterized by a set of nonlocal string order parameters. The Hamiltonian possesses a hidden (Z2×Z2)n(Z_{2}\times Z_{2})^{n} topological symmetry. The breaking of this hidden symmetry leads to 4n4^{n} degenerate ground states with disentangled edge states in an open chain system. Such matrix product states can be regarded as cluster states, applicable to measurement-based quantum computation.Comment: 5 pages, 1 figur

    Numerical simulation on the ventilated cavitating flow with high Froude number

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    A numerical scheme based on the homogeneous multiphase model was proposed to model the ventilated cavitating flow by considering interaction between three phases including vapor, ventilated gas and liquid. Due to the difficulty of carrying out ventilated cavitation experiments in high-speed water tunnels, focus was put on predicting the developing process of the cavitating flow with high Froude number. The evolution processes for the ventilated cavity which transited between different gas-leakage mechanisms were successfully captured, obtaining the variation of the cavitation number along with the ventilation rate. Hydrodynamics analysis was carried out for the cavitating body with low and high Froude number respectively, thereby revealing the ventilation rate to optimize the vehicle performance. Based on the numerical results, a theoretical gas-leakage model which was adapted to a wide range of Froude number and various gas-leakage mechanisms was proposed. The model was validated through comparison against experimental data and numerical results. This research provides valuable guidance on the design for ventilated cavitating vehicles

    Maximized string order parameters in the valence bond solid states of quantum integer spin chains

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    We propose a set of maximized string order parameters to describe the hidden topological order in the valence bond solid states of quantum integer spin-S chains. These optimized string order parameters involve spin-twist angles corresponding to ZS+1Z_{S+1} rotations around zz or xx-axes, suggesting a hidden ZS+1×ZS+1Z_{S+1}\times Z_{S+1} symmetry. Our results also suggest that a local triplet excitation in the valence bond solid states carries a ZS+1Z_{S+1} topological charge measured by these maximized string order parameters.Comment: 5 pages, 1 figur

    Associations between Aquaglyceroporin Gene Polymorphisms and Risk of Stroke among Patients with Hypertension

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    Background: Dysregulations ofAQP7andAQP9were found to be related to lipid metabolism abnormality, which had been provento be one of the mechanisms of stroke. However, limited epidemiological studies explore the associations betweenAQP7andAQP9and the risk of stroke among patients with hypertension in China. Aims: We aimed to investigate the associations between genetic variants in AQP7andAQP9and the risk of stroke among patients with hypertension, as well as to explore gene-gene andgene-environment interactions. Methods: Baseline blood samples were drawn from 211 cases with stroke and 633 matched controls. Genomic DNA was extracted by a commercially available kit. Genotyping of 5 single nucleotide polymorphisms (SNPs) in AQP7 (rs2989924, rs3758269, and rs2542743) and AQP9 (rs57139208, rs16939881) was performed by the polymerase chain reaction assay with TaqMan probes. Results: Participants with the rs2989924 GG genotype were found to be with a 1.74-fold increased risk of stroke compared to those with the AA+AG genotype, and this association remained significant after adjustment for potential confounders (odds ratio (OR): 1.74, 95% confidence interval (CI): 1.23-2.46). The SNP rs3758269 CC+TT genotype was found to be with a 33% decreased risk of stroke after multivariate adjustment (OR: 0.67, 95% CI: 0.45-0.99) compared to the rs3758269 CC genotype. The significantly increased risk of stroke was prominent among males, patients aged 60 or above, and participants who were overweight and with a harbored genetic variant in SNP rs2989924. After adjusting potential confounders, the SNP rs3758269 CT+TT genotype was found to be significantly associated with a decreased risk of stroke compared to the CC genotype among participants younger than 60 years old or overweight. No statistically significant associations were observed between genotypes of rs2542743, rs57139208, or rs16939881 with the risk of stroke. Neither interactions nor linkage disequilibrium had been observed in this study. Conclusions: This study suggests that SNPs rs2989924 and rs3758269 are associated with the risk of stroke among patients with hypertension, while there were no statistically significant associations between rs2542743, rs57139208, and rs16939881 and the risk of stroke being observed

    Digital economy, spatial spillover and carbon intensity: concurrently on the threshold effect of human capital

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    Under the new development pattern, green low-carbon and digital economy become two mainstream development directions in China. Against the background ‘dual carbon’ strategies, based on the data of China between 2010 and 2018 at the city level, The paper adopts dynamic spatial Durbin models to investigate the causal links causal between digital economy and carbon intensity by constructing different spatial weight matrices, and explore the influence of human capital with threshold model. Results show that:(1) Urban digital economy and carbon intensity show significant positive spatial correlation characteristics. The carbon reduction of digital economy has obvious spatial spillover effect under different spatial weight matrices. (2) Industrial structure upgrading, technological innovation and resource allocation optimization are effective channels through which digital economy contributes to carbon emission reduction. (3) A doublethreshold effect of human capital is evident in the carbon reduction of digital economy. The findings offer new perspectives and empirical evidence for understanding the causality relation between the digital economy and carbon emission, and those conclusions have important policy implications for how to promote the digital economy development and thus achieve the ‘double carbon goal’

    Numerical Simulation Research on the Characteristics of Tide and Salinity at Pearl River Estuary in China

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    Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv
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