25,103 research outputs found
A Synergistic Approach for Recovering Occlusion-Free Textured 3D Maps of Urban Facades from Heterogeneous Cartographic Data
In this paper we present a practical approach for generating an
occlusion-free textured 3D map of urban facades by the synergistic use of
terrestrial images, 3D point clouds and area-based information. Particularly in
dense urban environments, the high presence of urban objects in front of the
facades causes significant difficulties for several stages in computational
building modeling. Major challenges lie on the one hand in extracting complete
3D facade quadrilateral delimitations and on the other hand in generating
occlusion-free facade textures. For these reasons, we describe a
straightforward approach for completing and recovering facade geometry and
textures by exploiting the data complementarity of terrestrial multi-source
imagery and area-based information
Data-Driven Shape Analysis and Processing
Data-driven methods play an increasingly important role in discovering
geometric, structural, and semantic relationships between 3D shapes in
collections, and applying this analysis to support intelligent modeling,
editing, and visualization of geometric data. In contrast to traditional
approaches, a key feature of data-driven approaches is that they aggregate
information from a collection of shapes to improve the analysis and processing
of individual shapes. In addition, they are able to learn models that reason
about properties and relationships of shapes without relying on hard-coded
rules or explicitly programmed instructions. We provide an overview of the main
concepts and components of these techniques, and discuss their application to
shape classification, segmentation, matching, reconstruction, modeling and
exploration, as well as scene analysis and synthesis, through reviewing the
literature and relating the existing works with both qualitative and numerical
comparisons. We conclude our report with ideas that can inspire future research
in data-driven shape analysis and processing.Comment: 10 pages, 19 figure
Ordering kinetic in two-dimensional hexagonal pattern of cylinder-forming PS-b-PMMA block copolymer thin films: dependence on the segregation strength
This paper reports the experimental determination of the growth exponents and
activation enthalpies for the ordering process of standing cylinder-forming
all-organic polystyrene-block-poly (methyl methacrylate) (PS-b-PMMA) block
copolymer (BCP) thin films as a function of the BCP degree of polymerization
(N). The maximum growth exponent of 1/3 is observed for the smallest BCP at the
border of the order disorder transition. Both the growth exponents and the
activation enthalpies exponentially decrease with the BCP segregation strength
(chi N) following the same path of the diffusivity.Comment: 17 pages, 3 figures, 1 table, 7 pages (18-24) Supplemental Material
(SM
DeepSketch2Face: A Deep Learning Based Sketching System for 3D Face and Caricature Modeling
Face modeling has been paid much attention in the field of visual computing.
There exist many scenarios, including cartoon characters, avatars for social
media, 3D face caricatures as well as face-related art and design, where
low-cost interactive face modeling is a popular approach especially among
amateur users. In this paper, we propose a deep learning based sketching system
for 3D face and caricature modeling. This system has a labor-efficient
sketching interface, that allows the user to draw freehand imprecise yet
expressive 2D lines representing the contours of facial features. A novel CNN
based deep regression network is designed for inferring 3D face models from 2D
sketches. Our network fuses both CNN and shape based features of the input
sketch, and has two independent branches of fully connected layers generating
independent subsets of coefficients for a bilinear face representation. Our
system also supports gesture based interactions for users to further manipulate
initial face models. Both user studies and numerical results indicate that our
sketching system can help users create face models quickly and effectively. A
significantly expanded face database with diverse identities, expressions and
levels of exaggeration is constructed to promote further research and
evaluation of face modeling techniques.Comment: 12 pages, 16 figures, to appear in SIGGRAPH 201
Facts, skills and intuition : A typology of personal knowledge
This paper introduces a knowledge model in which the types of knowledge are formed according to the nature of knowledge. First we use Ryle’s distinction of “that” and “how” knowledge, to which we add further three types. The five knowledge types are then synthesized using Polanyi’s distinction of focal and subsidiary awareness. The resulting model distinguishes three types of knowledge, the facts, the skills, and the intuition; all three having focal and subsidiary parts. We believe that this knowledge model is comprehensive in the sense that can classify any knowledge and it also has great explanatory power, as it is demonstrated through illustrative examples. Moreover, the model is elegant and easy to use, which facilitates our understanding of the domain of personal knowledge. Therefore we expect our findings to be useful for both researchers and educators in the field of knowledge and knowledge management
STM study of self-assembled phthalocyanine derivatives and their hosting properties
Molecular self-assembly, as a most studied case of self-assembly, is one of the few practical strategies for making ensembles of nano- and micro structures. As an essential aspect of the “bottom-up” approach, it is attractive for both scientific research and technological applications. Therefore a detailed understanding of the molecule-substrate and intermolecular interactions involved in the self-assembly process is of great interest.
In the first part of the thesis, the influence of the phenoxy substituents on the self-assembly of Pcs on (111)-oriented noble metal surfaces is described. The rotational degrees of freedom, characteristic for these substituents enable the formation of various stable and transient phases and allow the substituents to be arranged above the plane of the Pc core, forming a bowl-like structure, which in turn enables the interaction of the Pc core with the metal substrate. The proximity of the Pc core to the metal substrate together with the steric entanglement between neighboring substituents causes significant retardation of the thermodynamic optimization of the conformations. This accounts for the coexistence of some of the phases.
In the second part, the influence of replacing two adjacent phenoxy substituents by a rigid tetraazatriphenylene substituent on the self-assembly of Pcs is analyzed and compared to the self-assembly of the above mentioned phenoxy substituted Pcs. The rigid substituent enhances the rotational degrees of freedom of the neighboring phenoxy substituents, hence facilitates their conformational optimization. As a result, novel interactions between the Pc derivatives are enabled and the formation of ordered phases with higher surface densities compared to the previous study is observed.
In the third part, the hosting properties of a close-packed layer of phenoxy substituted Pc derivatives adsorbed on Ag(111) are investigated for the adsorption of C60 molecules. The C60 molecules bind to two clearly distinguishable sites, either to the underlying metal substrate in between two adjacent Pc derivatives or to the core of a Pc derivative. In the first case, the C60 exhibit morphologic and electronic properties analogous to those of a C60 adsorbed on clean Ag(111), whereas in the second case the electronic properties indicate a strong interaction between C60 and the phthalocyanine core
Recovering occlusion-free textured 3D maps of urban facades by a synergistic use of terrestrial images, 3D point clouds and area-based information
In this paper we present a practical approach for generating an occlusion-free textured 3D map of urban facades by the synergistic
use of terrestrial images, 3D point clouds and area-based information. Particularly in dense urban environments, the high presence
of urban objects in front of the facades causes significant difficulties for several stages in computational building modeling. Major
challenges lie on the one hand in extracting complete 3D facade quadrilateral delimitations and on the other hand in generating
occlusion-free facade textures. For these reasons, we describe a straightforward approach for completing and recovering facade
geometry and textures by exploiting the data complementarity of terrestrial multi-source imagery and area-based information
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