| 1. |
- Abelev, Betty, et al.
(författare)
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Long-range angular correlations on the near and away side in p-Pb collisions at root S-NN=5.02 TeV
- 2013
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 719:1-3, s. 29-41
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Tidskriftsartikel (refereegranskat)abstract
- Angular correlations between charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV for transverse momentum ranges within 0.5 < P-T,P-assoc < P-T,P-trig < 4 GeV/c. The correlations are measured over two units of pseudorapidity and full azimuthal angle in different intervals of event multiplicity, and expressed as associated yield per trigger particle. Two long-range ridge-like structures, one on the near side and one on the away side, are observed when the per-trigger yield obtained in low-multiplicity events is subtracted from the one in high-multiplicity events. The excess on the near-side is qualitatively similar to that recently reported by the CMS Collaboration, while the excess on the away-side is reported for the first time. The two-ridge structure projected onto azimuthal angle is quantified with the second and third Fourier coefficients as well as by near-side and away-side yields and widths. The yields on the near side and on the away side are equal within the uncertainties for all studied event multiplicity and p(T) bins, and the widths show no significant evolution with event multiplicity or p(T). These findings suggest that the near-side ridge is accompanied by an essentially identical away-side ridge. (c) 2013 CERN. Published by Elsevier B.V. All rights reserved.
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| 2. |
- Abelev, Betty, et al.
(författare)
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Measurement of prompt J/psi and beauty hadron production cross sections at mid-rapidity in pp collisions at root s=7 TeV
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.
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| 3. |
- Bo, Mao, et al.
(författare)
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Real-time visualization of 3D city models at street-level based on visual saliency
- 2015
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Ingår i: Science China: Earth Sciences. - : Springer Science and Business Media LLC. - 1674-7313 .- 1869-1897. ; 58:3, s. 448-461
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Tidskriftsartikel (refereegranskat)abstract
- Street-level visualization is an important application of 3D city models. Challenges to street-level visualization include the cluttering of buildings due to fine detail and visualization performance. In this paper, a novel method is proposed for street-level visualization based on visual saliency evaluation. The basic idea of the method is to preserve these salient buildings in a scene while removing those that are non-salient. The method can be divided into pre-processing procedures and real-time visualization. The first step in pre-processing is to convert 3D building models at higher Levels of Detail (LoDs) into LoD1 models with simplified ground plans. Then, a number of index viewpoints are created along the streets; these indices refer to both the position and the direction of each street site. A visual saliency value is computed for each building, with respect to the index site, based on a visual difference between the original model and the generalized model. We calculate and evaluate three methods for visual saliency: local difference, global difference and minimum projection area. The real-time visualization process begins by mapping the observer to its closest indices. The street view is then generated based on the building information stored in those indexes. A user study shows that the local visual saliency method performs better than do the global visual saliency, area and image-based methods and that the framework proposed in this paper may improve the performance of 3D visualization.
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| 4. |
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| 5. |
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| 6. |
- Mao, Bo, 1983-, et al.
(författare)
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A Dynamic Typification Method of 3D City Models using Minimum Spanning Tree
- 2010
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Ingår i: Proc. 6th international conference on Geographic Information Science.
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Konferensbidrag (refereegranskat)abstract
- A novel method based on MST for 3D City model typification is proposed. The 3D building models in higher LODs are converted into LOD1 with simplified ground plan and height. Minimum spanning tree (MST) of the ground plan centroid is generated and divided into sub-MSTs by road network. The building lists in each sub-MST with linear structure are selected, based on which typification model is created. According to the visualization evaluation and experiments, our method can reduce the building numbers while preserve the visual similarity well for selected city area.
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| 7. |
- Mao, Bo, 1983-, et al.
(författare)
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A Framework of Online 3D City Visualization using CityGML and X3D
- 2009
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Ingår i: The 6th International Symposium on Digital Earth.
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Konferensbidrag (refereegranskat)abstract
- In this paper, a novel framework based on CityGML and X3D is proposed to support visualization of 3D City Model through Internet. In the proposed framework, the CityGML files are first parsed to acquire the city model information. Citygml4j, an open source java API, is used for this parsing. Then, the X3D representation is generated based on the city model by the proposed algorithm which can dynamically create different 3D city models according to corresponding Levels of Detail (LOD). Finally, the 3D city scene in X3D format is displayed through Internet with java applet or other X3D viewers. The Java Applets are created using the Xj3D toolkit. The preliminary experiment shows that the framework can correctly and efficiently exhibit the3D city model via Internet.
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| 8. |
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| 9. |
- Mao, Bo, 1983-, et al.
(författare)
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A multiple representation data structure for dynamic visualisation of generalised 3D city models
- 2011
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Ingår i: ISPRS Journal of Photogrammetry and Remote Sensing. - : Elsevier BV. - 0924-2716 .- 1872-8235. ; 66:2, s. 198-208
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a novel multiple representation data structure for dynamic visualisation of 3D city models, called CityTree, is proposed. To create a CityTree, the ground plans of the buildings are generated and simplified. Then, the buildings are divided into clusters by the road network and one CityTree is created for each cluster. The leaf nodes of the CityTree represent the original 3D objects of each building, and the intermediate nodes represent groups of close buildings. By utilising CityTree, it is possible to have dynamic zoom functionality in real time. The CityTree methodology is implemented in a framework where the original city model is stored in CityGML and the CityTree is stored as X3D scenes. A case study confirms the applicability of the CityTree for dynamic visualisation of 3D city models. (C) 2010 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS). Published by Elsevier B.V. All rights reserved.
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| 10. |
- Mao, Bo, 1983-, et al.
(författare)
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A multiple representation data structure of 3D building textures
- 2011
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Texture is an important element for visualization of 3D city models and often takes a big proportion of the total data volume. In order to simplify 3D city model textures for dynamic visualization in different scales, a multiple representation data structure, TextureTree is proposed to store building textures in different LoDs. First, the texture image is iteratively segmented by horizontal or vertical dividing zone (edge or background from edge detection) until each sections are basically in the same color. Then textures in all sections are represented by their main color and the TextureTree is created based on the color difference between the adjacent sections. With the TextureTree, the simplified texture in different LoDs can be dynamically generated. The experiment results show that the data volume of building textures can be reduced by TextureTree while the required visual similarity is preserved.
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