The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Jonathan Roberts - One of the best experts on this subject based on the ideXlab platform.
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Geometric Interpretation of the general POE model for a serial-link robot via conversion into D-H parameterization
2019 International Conference on Robotics and Automation (ICRA), 2019Co-Authors: Liao Wu, Ross Crawford, Jonathan RobertsAbstract:While Product of Exponentials (POE) formula has been gaining maturity in modeling the kinematics of a serial-link robot, the Denavit-Hartenberg (D-H) notation is still the most widely used due to its intuitive and concise Geometric Interpretation of the robot. This paper has developed an analytical solution to automatically convert a POE model into a D-H model for a robot with revolute, prismatic, and helical joints, which are the complete set of three basic one degree of freedom lower pair joints for constructing a serial-link robot. The conversion algorithm developed can be used in applications such as calibration where it is necessary to convert the D-H model to the POE model for identification and then back to the D-H model for compensation. The equivalence of the two models proved in this paper also benefits the analysis of the identifiability of the kinematic parameters. It is found that the maximum number of identifiable parameters in a general POE model is 5h+4r+2t+n+6 where h, r, t, and n stand for the number of helical, revolute, prismatic, and general joints, respectively. It is also suggested that the identifiability of the base frame and the tool frame in the D-H model is restricted rather than the arbitrary six parameters as assumed previously.
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Geometric Interpretation of the general poe model for a serial link robot via conversion into d h parameterization
arXiv: Robotics, 2019Co-Authors: Ross Crawford, Jonathan RobertsAbstract:While Product of Exponentials (POE) formula has been gaining increasing popularity in modeling the kinematics of a serial-link robot, the Denavit-Hartenberg (D-H) notation is still the most widely used due to its intuitive and concise Geometric Interpretation of the robot. This paper has developed an analytical solution to automatically convert a POE model into a D-H model for a robot with revolute, prismatic, and helical joints, which are the complete set of three basic one degree of freedom lower pair joints for constructing a serial-link robot. The conversion algorithm developed can be used in applications such as calibration where it is necessary to convert the D-H model to the POE model for identification and then back to the D-H model for compensation. The equivalence of the two models proved in this paper also benefits the analysis of the identifiability of the kinematic parameters. It is found that the maximum number of identifiable parameters in a general POE model is 5h+4r +2t +n+6 where h, r, t, and n stand for the number of helical, revolute, prismatic, and general joints, respectively. It is also suggested that the identifiability of the base frame and the tool frame in the D-H model is restricted rather than the arbitrary six parameters as assumed previously.
Matthieu Wyart - One of the best experts on this subject based on the ideXlab platform.
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Geometric Interpretation of previtrification in hard sphere liquids
Journal of Chemical Physics, 2009Co-Authors: Carolina Brito, Matthieu WyartAbstract:We derive a microscopic criterion for the stability of hard sphere configurations and we show empirically that this criterion is marginally satisfied in the glass. This observation supports a Geometric Interpretation for the initial rapid rise in viscosity with packing fraction or previtrification. It also implies that barely stable soft modes characterize the glass structure, whose spatial extension is estimated. We show that both the short-term dynamics and activation processes occur mostly along those soft modes and we study some implications of these observations. This article synthesizes new and previous results [C. Brito and M. Wyart, Europhys. Lett. 76, 149 (2006); C. Brito and M. Wyart, J. Stat. Mech.: Theory Exp. 2007, L08003] in a unified view.
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Geometric Interpretation of pre vitrification in hard sphere liquids
arXiv: Soft Condensed Matter, 2009Co-Authors: Carolina Brito, Matthieu WyartAbstract:We derive a microscopic criterion for the stability of hard sphere configurations, and we show empirically that this criterion is marginally satisfied in the glass. This observation supports a Geometric Interpretation for the initial rapid rise of viscosity with packing fraction, or pre-vitrification. It also implies that barely stable soft modes characterize the glass structure, whose spatial extension is estimated. We show that both the short-term dynamics and activation processes occur mostly along those soft modes, and we study some implications of these observations. This article synthesizes new and previous results [C. Brito and M. Wyart, Euro. Phys. Letters, {\bf 76}, 149-155, (2006) and C. Brito and M. Wyart, J. Stat. Mech., L08003 (2007) ] in a unified view.
Amir Globerson - One of the best experts on this subject based on the ideXlab platform.
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a simple Geometric Interpretation of svm using stochastic adversaries
International Conference on Artificial Intelligence and Statistics, 2012Co-Authors: Roi Livni, Koby Crammer, Amir GlobersonAbstract:We present a minimax framework for classification that considers stochastic adversarial perturbations to the training data. We show that for binary classification it is equivalent to SVM, but with a very natural Interpretation of regularization parameter. In the multiclass case, we obtain that our formulation is equivalent to regularizing the hinge loss with the maximum norm of the weight vector (i.e., the two-infinity norm). We test this new regularization scheme and show that it is competitive with the Frobenius regularization commonly used for multiclass SVM. We proceed to analyze various forms of stochastic perturbations and obtain compact optimization problems for the optimal classifiers. Taken together, our results illustrate the advantage of using stochastic perturbations rather than deterministic ones, as well as oer a simple Geometric Interpretation for SVM optimization.
Liljana Gavrilovska - One of the best experts on this subject based on the ideXlab platform.
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Geometric Interpretation of theoretical bounds for rss based source localization with uncertain anchor positions
Digital Signal Processing, 2017Co-Authors: Daniel Denkovski, Marko Angjelichinoski, Vladimir Atanasovski, Liljana GavrilovskaAbstract:Abstract The Received Signal Strength based source localization can encounter severe problems originating from uncertain information about the anchor positions in practice. The anchor positions, although commonly assumed to be precisely known prior to the source localization, are usually obtained using previous estimation algorithm such as GPS. This previous estimation procedure produces anchor positions with limited accuracy that result in degradations of the source localization algorithm and topology uncertainty. We have recently addressed the problem with a joint estimation framework that jointly estimates the unknown source and uncertain anchors positions and derived the theoretical limits of the framework. This paper extends the authors previous work on the theoretical performance bounds of the joint localization framework with appropriate Geometric Interpretation of the overall problem. It exploits the properties of semi-definiteness and symmetry of the Fisher Information Matrix and the Cramer–Rao Lower Bound to derive Information and Error Ellipses, respectively. The numerical results aim to illustrate and discuss the usefulness of the Geometric Interpretation. They provide in-depth insight into the Geometrical properties of the joint localization problem underlining the various possibilities for practical design of efficient localization algorithms.
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Geometric Interpretation of theoretical bounds for rss based source localization with uncertain anchor positions
arXiv: Information Theory, 2016Co-Authors: Daniel Denkovski, Marko Angjelichinoski, Vladimir Atanasovski, Liljana GavrilovskaAbstract:The Received Signal Strength based source localization can encounter severe problems originating from uncertain information about the anchor positions in practice. The anchor positions, although commonly assumed to be precisely known prior to the source localization, are usually obtained using previous estimation algorithm such as GPS. This previous estimation procedure produces anchor positions with limited accuracy that result in degradations of the source localization algorithm and topology uncertainty. We have recently addressed the problem with a joint estimation framework that jointly estimates the unknown source and uncertain anchors positions and derived the theoretical limits of the framework. This paper extends the authors previous work on the theoretical performance bounds of the joint localization framework with appropriate Geometric Interpretation of the overall problem exploiting the properties of semi-definiteness and symmetry of the Fisher Information Matrix and the Cram{e}r-Rao Lower Bound and using Information and Error Ellipses, respectively. The numerical results aim to illustrate and discuss the usefulness of the Geometric Interpretation. They provide in-depth insight into the Geometrical properties of the joint localization problem underlining the various possibilities for practical design of efficient localization algorithms.
Liao Wu - One of the best experts on this subject based on the ideXlab platform.
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Geometric Interpretation of the general POE model for a serial-link robot via conversion into D-H parameterization
2019 International Conference on Robotics and Automation (ICRA), 2019Co-Authors: Liao Wu, Ross Crawford, Jonathan RobertsAbstract:While Product of Exponentials (POE) formula has been gaining maturity in modeling the kinematics of a serial-link robot, the Denavit-Hartenberg (D-H) notation is still the most widely used due to its intuitive and concise Geometric Interpretation of the robot. This paper has developed an analytical solution to automatically convert a POE model into a D-H model for a robot with revolute, prismatic, and helical joints, which are the complete set of three basic one degree of freedom lower pair joints for constructing a serial-link robot. The conversion algorithm developed can be used in applications such as calibration where it is necessary to convert the D-H model to the POE model for identification and then back to the D-H model for compensation. The equivalence of the two models proved in this paper also benefits the analysis of the identifiability of the kinematic parameters. It is found that the maximum number of identifiable parameters in a general POE model is 5h+4r+2t+n+6 where h, r, t, and n stand for the number of helical, revolute, prismatic, and general joints, respectively. It is also suggested that the identifiability of the base frame and the tool frame in the D-H model is restricted rather than the arbitrary six parameters as assumed previously.
