The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Shiqi Duan - One of the best experts on this subject based on the ideXlab platform.
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MLICOM (2) - Obtaining Ellipse Common Tangent Line Equations by the Rolling Tangent Line Method
Machine Learning and Intelligent Communications, 2018Co-Authors: Naizhang Feng, Teng Jiang, Shiqi DuanAbstract:In the field of image processing and machine vision, it is sometimes necessary to obtain Common Tangent line equations and Tangent point coordinates from ellipses. A rolling Tangent line method was proposed to obtain the 4 Common Tangent line equations and 8 Tangent point coordinates from two ellipses in this paper. The principle of this method is simple and it is easy to program on a computer. Use this method to process two ellipse targets in an image and the experiment results show that the 4 Common Tangent equations and 8 Tangent point coordinates can be obtained in high precision and the maximum execution time is less than 0.1 s.
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obtaining ellipse Common Tangent line equations by the rolling Tangent line method
International Conference on Machine Learning, 2017Co-Authors: Naizhang Feng, Teng Jiang, Shiqi DuanAbstract:In the field of image processing and machine vision, it is sometimes necessary to obtain Common Tangent line equations and Tangent point coordinates from ellipses. A rolling Tangent line method was proposed to obtain the 4 Common Tangent line equations and 8 Tangent point coordinates from two ellipses in this paper. The principle of this method is simple and it is easy to program on a computer. Use this method to process two ellipse targets in an image and the experiment results show that the 4 Common Tangent equations and 8 Tangent point coordinates can be obtained in high precision and the maximum execution time is less than 0.1 s.
Thorsten Theobald - One of the best experts on this subject based on the ideXlab platform.
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Algorithmic and Quantitative Aspects of Real Algebraic Geometry in Mathematics and Computer Science - Visibility Computations: From Discrete Algorithms to Real Algebraic Geometry.
2020Co-Authors: Thorsten TheobaldAbstract:We investigate visibility computations with moving viewpoints. The initial problems are of discrete and algorithmic nature, but even for simple classes of objects (such as balls and polytopes), they lead to interesting and difficult problems from real algebraic geometry. Namely, it is necessary to characterize and compute the Common Tangent lines to a given set of convex bodies. In particular, we present a new sweep algorithm in dimension 2, as well as survey and extend recent algebraic-geometric results on the Tangent problems
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Lines Tangent to 2-2 spheres in ℝⁿ
Transactions of the American Mathematical Society, 2002Co-Authors: Frank Sottile, Thorsten TheobaldAbstract:We show that for n ≥ 3 there are 3.2 n-1 complex Common Tangent lines to 2n - 2 general spheres in R n and that there is a choice of spheres with all Common Tangents real.
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An Enumerative Geometry Framework for Algorithmic Line Problems in $\mathbb R^3$
SIAM Journal on Computing, 2002Co-Authors: Thorsten TheobaldAbstract:We investigate the enumerative geometry aspects of algorithmic line problems when the admissible bodies are balls or polytopes. For this purpose, we study the Common Tangent lines/transversals to k balls of arbitrary radii and 4-k lines in ${\mathbb R}^3$. In particular, we compute tight upper bounds for the maximum number of real Common Tangents/transversals in these cases. Our results extend the results of Macdonald, Pach, and Theobald who investigated Common Tangents to four unit balls in ${\mathbb R}^3$ [Discrete Comput. Geom., 26 (2001), pp. 1--17].
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How to realize a given number of Tangents to four unit balls in ℝ 3
Mathematika, 2001Co-Authors: Thorsten TheobaldAbstract:By a recent result, the number of Common Tangent lines to four unit balls in ℝ 3 is bounded by 12 unless the four centres are collinear. In the present paper, this result is complemented by showing that indeed every number of Tangents k ∈ {0, …, 12} can be established in real space. The constructions combine geometric and algebraic aspects of the Tangent problem.
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Lines Tangent to 2n-2 spheres in R^n
arXiv: Algebraic Geometry, 2001Co-Authors: Frank Sottile, Thorsten TheobaldAbstract:We show that there are 3 \cdot 2^(n-1) complex Common Tangent lines to 2n-2 general spheres in R^n and that there is a choice of spheres with all Common Tangents real.
Stefano Brandani - One of the best experts on this subject based on the ideXlab platform.
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Common Tangent plane in mixed gas adsorption
Fluid Phase Equilibria, 2015Co-Authors: Giulio Santori, Mauro Luberti, Stefano BrandaniAbstract:Abstract The minimisation of the distance function between the Gibbs energy of mixing and its Common Tangent plane (or line) is applied to adsorbed solutions. A specific algorithm to deal with the associated bilevel programming problem is presented and discussed. This approach is validated with experimental data and ideal adsorbed solution theory calculations for an ideal case and with experimental data for two non-ideal cases at low and high pressure. While the presently adopted non-ideal formulation provides solutions fulfilling only the necessary condition for equilibrium, the Common Tangent plane approach proposed in this paper enables the direct evaluation of the necessary and sufficient solution.
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An algorithm for the regression of the UNIQUAC interaction parameters in liquid–liquid equilibrium for single- and multi-temperature experimental data
Fluid Phase Equilibria, 2014Co-Authors: Giulio Santori, Stefano Brandani, Matteo Franciolini, Giovanni Di Nicola, Fabio Polonara, Roman StryjekAbstract:Abstract This paper describes an algorithm for the computation of the UNIQUAC interaction parameters from liquid–liquid experimental data. The algorithm comprises two separate levels. The inner level is devoted to the calculation of the interaction parameters, minimizing an objective function which is function of the activities. The outer level uses the parameters by the inner level and aims to minimize the error between experimental and calculated molar fractions through an adjustment of the experimental molar fractions, provided that the condition of Common Tangent to the change of the Gibbs free energy of mixing is matched. The algorithm is applied to seven binary systems for the evaluation of single temperature parameters and to the tetrahydrofuran/water system for the evaluation of the temperature dependent parameters. In both cases, the calculated parameters provide results with lower error than the previously published parameters. In all cases thermodynamically consistent and precise results are obtained in terms of Common Tangent of the Gibbs free energy of mixing and molar faction errors.
Naizhang Feng - One of the best experts on this subject based on the ideXlab platform.
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MLICOM (2) - Obtaining Ellipse Common Tangent Line Equations by the Rolling Tangent Line Method
Machine Learning and Intelligent Communications, 2018Co-Authors: Naizhang Feng, Teng Jiang, Shiqi DuanAbstract:In the field of image processing and machine vision, it is sometimes necessary to obtain Common Tangent line equations and Tangent point coordinates from ellipses. A rolling Tangent line method was proposed to obtain the 4 Common Tangent line equations and 8 Tangent point coordinates from two ellipses in this paper. The principle of this method is simple and it is easy to program on a computer. Use this method to process two ellipse targets in an image and the experiment results show that the 4 Common Tangent equations and 8 Tangent point coordinates can be obtained in high precision and the maximum execution time is less than 0.1 s.
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obtaining ellipse Common Tangent line equations by the rolling Tangent line method
International Conference on Machine Learning, 2017Co-Authors: Naizhang Feng, Teng Jiang, Shiqi DuanAbstract:In the field of image processing and machine vision, it is sometimes necessary to obtain Common Tangent line equations and Tangent point coordinates from ellipses. A rolling Tangent line method was proposed to obtain the 4 Common Tangent line equations and 8 Tangent point coordinates from two ellipses in this paper. The principle of this method is simple and it is easy to program on a computer. Use this method to process two ellipse targets in an image and the experiment results show that the 4 Common Tangent equations and 8 Tangent point coordinates can be obtained in high precision and the maximum execution time is less than 0.1 s.
Thibaut Cachon - One of the best experts on this subject based on the ideXlab platform.
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Comparison of radiographic measurements of the patellar tendon-tibial plateau angle with anatomical measurements in dogs: Validity of the Common Tangent and tibial plateau methods
Veterinary and Comparative Orthopaedics and Traumatology, 2014Co-Authors: C. Bismuth, D. Fau, P. Pillard, C. Deroy, Antoine Labrunie, B. Marin, François-xavier Ferrand, Maurice Millet, Claude Carozzo, Thibaut CachonAbstract:Global ICC for the Common Tangent method (0.44) and for the conventional method (0.4) with 6 observers indicated their overall validity is poor. The measurements obtained by CT method and conventional method were respectively below and above the anatomical measurements. The reproducibility of the PTA measurements based on images of the dissected stifles was very good. The measurements obtained by Common Tangent and conventional method were below and above the anatomical measurements. The reproducibility of the PTA measurements based on images of the dissected stifles was very good. Both the CT and conventional methods show poor concordance with the anatomical measurement of PTA.
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comparison of radiographic measurements of the patellar tendon tibial plateau angle with anatomical measurements in dogs validity of the Common Tangent and tibial plateau methods
Veterinary and Comparative Orthopaedics and Traumatology, 2014Co-Authors: C. Bismuth, P. Pillard, C. Deroy, Antoine Labrunie, B. Marin, François-xavier Ferrand, Thibaut Cachon, Maurice Millet, Claude Carozzo, E ViguierAbstract:Objective: To evaluate the validity of the Common Tangent and conventional tibial plateau angle methods for measuring the patellar tendon angle (PTA) in dogs. Methods: Radiographs of cadaveric stifles (n = 20) placed at 135° in true lateral position were obtained to measure the PTA with both methods. A Kirschner wire was inserted perpendicularly to the patellar tendon at its insertion on the tibia and the stifle was dissected. Two Kirschner wires were then used to identify the anatomical landmarks of the tibial plateau. A digital image was obtained of the proximal tibia in true lateral position. Six blinded observers measured each PTA digitally while the anatomical PTA was determined by an independent blinded observer from the angle between the line representing the tibial plateau and the Kirschner wire representing the perpendicular to the patellar tendon. The agreement between the methods was determined statistically from an intraclass correlation coefficient (ICC). Results: The global ICC for the Common Tangent method (0.44) and for the conventional method (0.4) indicated that their overall validity is poor. The measurements obtained by Common Tangentmethod and conventional method were respectively below and above the anatomical measurements. The reproducibility of the PTA measurements based on images of the dissected stifles was very good. Clinical significance: Both the Common Tangent and conventional methods show poor concordance with the anatomical measurement of PTA. Further studies are needed to determine if errors in measurements affect the clinical outcome.
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measurement of the patellar tendon tibial plateau angle and tuberosity advancement in dogs with cranial cruciate ligament rupture reliability of the Common Tangent and tibial plateau methods of measurement
Veterinary and Comparative Orthopaedics and Traumatology, 2013Co-Authors: M Millet, C. Bismuth, P. Pillard, Antoine Labrunie, B. Marin, Thibaut Cachon, A Filleur, Juliette Sonet, S EtcheparebordeAbstract:Objectives: To (i) compare agreement of the Common Tangent (CT) and tibial plateau angle (TP) methods in terms of measuring the patellar tendon angle (PTA) and required advancement and (ii) determine the intra- and inter-observer reliability of observers who measured PTA and the advancement. Methods: Six observers were divided into three groups based on their level of experience. They measured the PTA and the required advancement on 43 radiographic images of the tibiae of dogs affected by cranial cruciate ligament rupture. Each observer repeated the measurements three times with each method. The inter-technique (interT), intra-observer (intraO), and interobserver (interO) reliabilities were evaluated, assessed by calculating the intraclass correlation coefficient (ICC), and represented by Jones plots. Results: The agreement between PTA-CT and PTA-TP was low (the ICC interT values ranged from 0.11 to 0.4). The PTA-CT was associated with moderate intra-observer reliability (ICC intraO, CT = 0.61) and poor interobserver reliability (ICC interO, CT = 0.33). The PTA-TP was associated with good intra-observer reliability (ICC intraO, TP = 0.75) and moderate interobserver reliability (ICC interO, TP = 0.59). Interobserver reliability did not depend on the level of experience. The advancement measurements were associated with reliability results similar to those obtained for PTA. Jones’ plots showed that the CT method consistently yielded lower PTA and advancement values than the TP method. Conclusion: Given its poor reliability, the CT method is not recommended.