| 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. |
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| 4. |
- 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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| 5. |
- 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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| 6. |
- 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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| 7. |
- Mao, Bo, et al.
(författare)
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City Model Generalization Quality Assessment using Nested Structure of Earth Mover’s Distance
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- To evaluate the quality of city model generalization, an attributed relational graph (ARG) is used to represent the features of city models and Nested structure of Earth Mover's Distance (NEMD) is employed to calculate the visual similarity of the ARGs. The experiments show that the proposed method is coherence with user survey result.
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| 8. |
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| 9. |
- Mao, Bo, 1983-, et al.
(författare)
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Detection and typification of linear structures for dynamic visualization of 3D city models
- 2012
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Ingår i: Computers, Environment and Urban Systems. - : Elsevier BV. - 0198-9715 .- 1873-7587. ; 36:3, s. 233-244
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Tidskriftsartikel (refereegranskat)abstract
- Cluttering is a fundamental problem in 3D city model visualization. In this paper, a novel method for removing cluttering by typification of linear building groups is proposed. This method works. in static as well as dynamic visualization of 3D city models. The method starts by converting building models in higher Levels of Details (LoDs) into LoD1 with ground plan and height. Then the Minimum Spanning Tree (MST) is generated according to the distance between the building ground plans. Based on the MST, linear building groups are detected for typification. The typification level of a building group is determined by its distance to the viewpoint as well as its viewing angle. Next, the selected buildings are removed and the remaining ones are adjusted in each group separately. To preserve the building features and their spatial distribution, Attributed Relational Graph (ARC) and Nested Earth Mover's Distance (NEMD) are used to evaluate the difference between the original building objects and the generalized ones. The experimental results indicate that our method can reduce the number of buildings while preserving the visual similarity of the urban areas. (C) 2011 Elsevier Ltd. All rights reserved.
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| 10. |
- Mao, Bo, 1983-, et al.
(författare)
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Generalisation of textured 3D city models using image compression and multiple representation data structure
- 2013
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Ingår i: ISPRS journal of photogrammetry and remote sensing (Print). - : Elsevier BV. - 0924-2716 .- 1872-8235. ; 79, s. 68-79
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Tidskriftsartikel (refereegranskat)abstract
- Texture is an essential part of 3D building models and it often takes up a big proportion of the data volume, thus makes dynamic visualization difficult. To compress the texture of 3D building models for the dynamic visualization in different scales, a multi-resolution texture generalization method is proposed, which contains two steps: texture image compression and texture coloring. In the first step, the texture images are compressed in both horizontal and vertical directions using wavelet transform. In the second step, TextureTreeis created to store the building color texture for the dynamic visualization from different distances. To generate TextureTree, texture images are iteratively ｓegmented by horizontal and vertical dividing zone, e.g. edge or background from edge detection, until each section is basically in the same color. Thentexture in each section is represented by their main color and the TextureTree iscreated based on the color difference between the adjacent sections. In dynamic visualization, the suitable compressed texture images or the TextureTree nodes are selected to generate the 3D scenes based on the angle and the distance between user viewpoint and the building surface. The experimental results indicate that the wavelet based image compression and proposed TextureTree can effectively represent the visual features of the textured buildings with much less data.
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