A formal classification of 3d medial axis points and their local geometry

2004 ◽  
Vol 26 (2) ◽  
pp. 238-251 ◽  
Author(s):  
P. Giblin ◽  
B.B. Kimia
Keyword(s):  
Medial Axis ◽  
Local Geometry ◽  
Formal Classification

The Walking Robot Control System that is Adaptive to Changes in the Kinematics

2021 ◽  
Vol 22 (11) ◽  
pp. 601-609
Author(s):  
A. S. Samoylova ◽  
S. A. Vorotnikov
Keyword(s):  
Genetic Algorithm ◽  
Control System ◽  
Robot Control ◽  
Control Algorithm ◽  
Human Life ◽  
Support Surface ◽  
Machine Modeling ◽  
Cargo Delivery ◽  
Formal Classification

The walking mobile robots (WMR) have recently become widely popular in robotics. They are especially useful in the extreme cases: search and rescue operations; cargo delivery over highly rough terrain; building a map. These robots also serve to explore and describe a partially or completely non-deterministic workspace, as well as to explore areas that are dangerous to human life. One of the main requirements for these WMR is the robustness of its control system. It allows WMR to maintain the operability when the characteristics of the support surface change as well as under more severe conditions, in particular, loss of controllability or damage of the supporting limb (SL). We propose to use the principles of genetic programming to create a WMR control system that allows a robot to adapt to possible changes in its kinematics, as well as to the characteristics of the support surface on which it moves. This approach does not require strong computational power or a strict formal classification of possible damage to the WMR. This article discusses two main WMR control modes: standard, which accord to a serviceable kinematics, and emergency, in which one or more SL drives are damaged or lost controllability. As an example, the structure of the control system of the WMP is proposed, the kinematics of which is partially destroyed in the process of movement. We developed a method for controlling such robot, which is based on the use of a genetic algorithm in conjunction with the Mealy machine. Modeling of modes of movement of WMR with six SL was carried out in the V-REP program for two cases of injury: absent and not functioning limb. We present the results of simulation of emergency gaits for these configurations of WMP and the effectiveness of the proposed method in the case of damage to the kinematic scheme. We also compared the performance of the genetic algorithm for the damaged WMR with the standard control algorithm.

A formal classification of Hopf-Bogdanov-Takens singularities of codimension three

2019 ◽  
Vol 480 (2) ◽  
pp. 123408
Author(s):  
Fátima Drubi ◽  
Santiago Ibáñez ◽  
David Rivela
Keyword(s):  
Formal Classification

Towards a new classification of tribe Stachydeae (Lamiaceae): naming clades using molecular evidence

2019 ◽  
Vol 190 (4) ◽  
pp. 345-358 ◽  
Author(s):  
Yasaman Salmaki ◽  
Günther Heubl ◽  
Maximilian Weigend
Keyword(s):  
Ribosomal Dna ◽  
Dna Sequences ◽  
Phylogenetic Relationships ◽  
Nuclear Ribosomal Dna ◽  
Molecular Evidence ◽  
New Classification ◽  
Formal Classification ◽  
Phylogenetic Nomenclature

AbstractStachydeae, comprising c. 470 species, are one of the most diverse and taxonomically puzzling groups in Lamioideae. In the present study, the phylogenetic relationships in the Eurystachys clade (a phylogenetic name for all genera attributed to Stachydeae except Melittis) were reconstructed utilizing nuclear ribosomal DNA sequences (nrETS, 5S-NTS) from 148 accessions in 12 genera. Our phylogenetic results recovered Stachys as paraphyletic with numerous traditionally recognized genera nested in it. A broadly defined Eurystachys clade, however, was monophyletic. Unlike previous studies, the present study was able to resolve the group into 12 well-supported clades, named here as (1) Eriostomum, (2) Stachys, (3) Prasium, (4) Setifolia, (5) Distantes, (6) Burgsdorfia, (7) Hesiodia, (8) Empedoclia, (9) Sideritis, (10) Marrubiastrum, (11) Swainsoniana and (12) Olisia. These 12 clades were formally named in a phylogenetic nomenclature for the Eurystachys clade. Several infrageneric units were retrieved as monophyletic, namely Sideritis sections Burgsdorfia, Empedoclia and Hesiodia, Sideritis subgenus Marrubiastrum and Stachys sections Eriostomum (including Stachys section Mucronata) and Setifolia. The findings of this study also provide the basis for a future formal classification, with two options: (1) splitting of the Eurystachys clade into 12 monophyletic genera, all of them based on pre-existing genus names and redefined to encompass additional taxa, but without clear morphological apomorphies; or (2) lumping of all segregates into a broadly defined Stachys, including widely recognized and well-defined segregates such as Prasium and Sideritis.

Ambitoric geometry I: Einstein metrics and extremal ambikähler structures

2016 ◽  
Vol 2016 (721) ◽  
Author(s):  
Vestislav Apostolov ◽  
David M. J. Calderbank ◽  
Paul Gauduchon
Keyword(s):  
Maxwell Equations ◽  
Einstein Metrics ◽  
Natural Extension ◽  
Torus Action ◽  
Local Geometry ◽  
Kähler Metrics ◽  
Kahler Metrics ◽  
Bach Tensor ◽  
Extremal Kähler Metrics

AbstractWe present a local classification of conformally equivalent but oppositely oriented 4-dimensional Kähler metrics which are toric with respect to a common 2-torus action. In the generic case, these “ambitoric” structures have an intriguing local geometry depending on a quadratic polynomialWe use this description to classify 4-dimensional Einstein metrics which are hermitian with respect to both orientations, as well as a class of solutions to the Einstein–Maxwell equations including riemannian analogues of the Plebański–Demiański metrics. Our classification can be viewed as a riemannian analogue of a result in relativity due to R. Debever, N. Kamran, and R. McLenaghan, and is a natural extension of the classification of selfdual Einstein hermitian 4-manifolds, obtained independently by R. Bryant and the first and third authors.These Einstein metrics are precisely the ambitoric structures with vanishing Bach tensor, and thus have the property that the associated toric Kähler metrics are extremal (in the sense of E. Calabi). Our main results also classify the latter, providing new examples of explicit extremal Kähler metrics. For both the Einstein–Maxwell and the extremal ambitoric structures,

scholarly journals FUSION OF FEATURE BASED AND DEEP LEARNING METHODS FOR CLASSIFICATION OF MMS POINT CLOUDS

2019 ◽  
Vol XLII-2/W16 ◽  
pp. 235-242 ◽  
Author(s):  
D. Tosic ◽  
S. Tuttas ◽  
L. Hoegner ◽  
U. Stilla
Keyword(s):  
Deep Learning ◽  
Point Cloud ◽  
Semantic Segmentation ◽  
Point Clouds ◽  
Local Geometry ◽  
Learning Approach ◽  
Semantic Classification ◽  
Feature Based ◽  
Urban Scene

<p><strong>Abstract.</strong> This work proposes an approach for semantic classification of an outdoor-scene point cloud acquired with a high precision Mobile Mapping System (MMS), with major goal to contribute to the automatic creation of High Definition (HD) Maps. The automatic point labeling is achieved by utilizing the combination of a feature-based approach for semantic classification of point clouds and a deep learning approach for semantic segmentation of images. Both, point cloud data, as well as the data from a multi-camera system are used for gaining spatial information in an urban scene. Two types of classification applied for this task are: 1) Feature-based approach, in which the point cloud is organized into a supervoxel structure for capturing geometric characteristics of points. Several geometric features are then extracted for appropriate representation of the local geometry, followed by removing the effect of local tendency for each supervoxel to enhance the distinction between similar structures. And lastly, the Random Forests (RF) algorithm is applied in the classification phase, for assigning labels to supervoxels and therefore to points within them. 2) The deep learning approach is employed for semantic segmentation of MMS images of the same scene. To achieve this, an implementation of Pyramid Scene Parsing Network is used. Resulting segmented images with each pixel containing a class label are then projected onto the point cloud, enabling label assignment for each point. At the end, experiment results are presented from a complex urban scene and the performance of this method is evaluated on a manually labeled dataset, for the deep learning and feature-based classification individually, as well as for the result of the labels fusion. The achieved overall accuracy with fusioned output is 0.87 on the final test set, which significantly outperforms the results of individual methods on the same point cloud. The labeled data is published on the TUM-PF Semantic-Labeling-Benchmark.</p>

scholarly journals The concept of «property» (according to the practice of the European court of human rights)

2021 ◽  
pp. 368-371
Author(s):  
M.V. Dobrev
Keyword(s):  
Human Rights ◽  
Property Rights ◽  
Case Law ◽  
Legal Systems ◽  
Council Of Europe ◽  
European Court ◽  
Formal Classification ◽  
Rights And Interests ◽  
Material Things

The article is devoted to the autonomous meaning of the term «property» used by the European Court of Human Rights. Emphasis is placed on the fact that in national legal systems, approaches to defining the concept of proper-ty, property rights have been and remain different. The violation of property as ownership exclusively of material things, excluding other rights and interests (substantive legal interests), the application of a formal classification of objects of law leads to violations of the right of everyone to own, use and dispose of their property by public author-ities and local governments. property. As the judgment of the European Court of Human Rights is a source of law in the member states of the Council of Europe, national law cannot contradict the Convention and the case law of the European Court of Human Rights.It is noted that the European Court of Human Rights, applying the autonomous meaning of the term «proper-ty», which does not depend on the formal classification of property rights in the national legislation of the mem-ber states of the Council of Europe, applies the following approaches to the concept of «property», the concept and content of property rights. that would be compatible with national legal systems. As a result of the analysis of the case law of the European Court of Human Rights, it was established that «property» is: 1) ownership of existing material things; 2) assets, including claims that the entity can claim to have at least a «legitimate ex-pectation» that they will be realized; 3) other rights and interests that constitute assets and can be considered as «property rights». Property that falls within the scope of Art. 1 of Protocol No. 1 to the Convention for the Protection of Human Rights and Fundamental Freedoms constitute, inter alia, economic resources to which natural persons have no registered property rights, but which have originally belonged to their ancestors and parents for economic activities, as well as income that individuals receive from the use of these resources.

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