27,826 research outputs found

    Towards Automatic SAR-Optical Stereogrammetry over Urban Areas using Very High Resolution Imagery

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    In this paper we discuss the potential and challenges regarding SAR-optical stereogrammetry for urban areas, using very-high-resolution (VHR) remote sensing imagery. Since we do this mainly from a geometrical point of view, we first analyze the height reconstruction accuracy to be expected for different stereogrammetric configurations. Then, we propose a strategy for simultaneous tie point matching and 3D reconstruction, which exploits an epipolar-like search window constraint. To drive the matching and ensure some robustness, we combine different established handcrafted similarity measures. For the experiments, we use real test data acquired by the Worldview-2, TerraSAR-X and MEMPHIS sensors. Our results show that SAR-optical stereogrammetry using VHR imagery is generally feasible with 3D positioning accuracies in the meter-domain, although the matching of these strongly hetereogeneous multi-sensor data remains very challenging. Keywords: Synthetic Aperture Radar (SAR), optical images, remote sensing, data fusion, stereogrammetr

    Comparison of Îł-ray spectrometry and ICP-MS methods for measuring radioactive heat-producing elements of rocks: a case study on borehole samples from the Sichuan Basin, China

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    We compared the consistency of Îł-ray spectrometry and inductively coupled plasma mass spectrometry by analyzing measurement results of the radioactive heat-producing elements U, Th, and K from borehole samples. This analysis was based on 49 samples obtained from mudstone, siltstone, and carbonate rock, and 11 of the 15 control groups showed great consistency. The radioactive heat production (RHP) of carbonate rocks was relatively low (0.23–0.63 ”W m−3) and was mainly contributed by U. Mudstone and siltstone have higher RHPs, which was 1.73 ± 0.46 and 2.04 ± 0.49 ”W m−3, respectively

    A Re-ranking Model for Dependency Parser with Recursive Convolutional Neural Network

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    In this work, we address the problem to model all the nodes (words or phrases) in a dependency tree with the dense representations. We propose a recursive convolutional neural network (RCNN) architecture to capture syntactic and compositional-semantic representations of phrases and words in a dependency tree. Different with the original recursive neural network, we introduce the convolution and pooling layers, which can model a variety of compositions by the feature maps and choose the most informative compositions by the pooling layers. Based on RCNN, we use a discriminative model to re-rank a kk-best list of candidate dependency parsing trees. The experiments show that RCNN is very effective to improve the state-of-the-art dependency parsing on both English and Chinese datasets

    Nuclear enhanced power corrections to DIS structure functions

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    We calculate nuclear enhanced power corrections to structure functions measured in deeply inelastic lepton-nucleus scattering in Quantum Chromodynamics (QCD). We find that the nuclear medium enhanced power corrections at order of O(αs/Q2)O(\alpha_s/Q^2) enhance the longitudinal structure function FLF_L, and suppress the transverse structure function F1F_1. We demonstrate that strong nuclear effects in σA/σD\sigma_A/\sigma_D and RA/RDR_A/R_D, recently observed by HERMES Collaboration, can be explained in terms of the nuclear enhanced power corrections.Comment: Latex, 10 pages including 3 figure

    Rescattering effects in hadron-nucleus and heavy-ion collisions

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    We review the extension of the factorization formalism of perturbative QCD to {\it coherent} soft rescattering associated with hard scattering in high energy nuclear collisions. We emphasize the ability to quantify high order corrections and the predictive power of factorization approach in terms of universal nonperturbative matrix elements. Although coherent rescattering effects are power suppressed by hard scales of the scattering, they are enhanced by the nuclear size and could play an important role in understanding the novel nuclear dependence observed in high energy nuclear collisions.Comment: 8 pages, 13 figures, to be published in the Proceedings of 1st International Conference on Hard and Electromagnetic Probes of High Energy Nuclear Collisions (Hard Probe 2004), Ericeira, Portugal, Nov. 4-10, 200

    A new approach to parton recombination in a QCD evolution equation

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    Parton recombination is reconsidered in perturbation theory without using the AGK cutting rules in the leading order of the recombination. We use time-ordered perturbation theory to sum the cut diagrams, which are neglected in the GLR evolution equation. We present a set of new evolution equations including parton recombination.Comment: 25 pages, LaTex, 10 PS figures, submmitted to Nucl. Phys.

    The Application of the English-Chinese Comparison to Discourse Structures Analysis

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    This paper makes an attempt to employ the English-Chinese comparison to English discourse structures analysis to help students avoiding some errors of interference from their native language and developing students’ linguistic skills to a high level of proficiency. Key words: the English language, the Chinese language, comparison, Discourse structure RĂ©sumĂ©: L’article prĂ©sent tente d’employer la comparaison anglais-chinois dans l’analyse de structure du discours anglais pour aider les Ă©tudiants Ă  Ă©viter des erreurs d’interfĂ©rence venues de leur langue maternelle et Ă  Ă©lĂ©ver leur le niveau linguistique. Mots-ClĂ©s: langue anglaise, langue chinoise, comparaison, structure du discour
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