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Supergravity for Effective Theories
Higher-derivative operators are central elements of any effective field
theory. In supersymmetric theories, these operators include terms with
derivatives in the K\"ahler potential. We develop a toolkit for coupling such
supersymmetric effective field theories to supergravity. We explain how to
write the action for minimal supergravity coupled to chiral superfields with
arbitrary numbers of derivatives and curvature couplings. We discuss two
examples in detail, showing how the component actions agree with the
expectations from the linearized description in terms of a Ferrara-Zumino
multiplet. In a companion paper, we apply the formalism to the effective theory
of inflation.Comment: 26 page
Patch-recovery filters for curvature in discontinuous Galerkin-based level-set methods
In two-phase flow simulations, a difficult issue is usually the treatment of
surface tension effects. These cause a pressure jump that is proportional to
the curvature of the interface separating the two fluids. Since the evaluation
of the curvature incorporates second derivatives, it is prone to numerical
instabilities. Within this work, the interface is described by a level-set
method based on a discontinuous Galerkin discretization. In order to stabilize
the evaluation of the curvature, a patch-recovery operation is employed. There
are numerous ways in which this filtering operation can be applied in the whole
process of curvature computation. Therefore, an extensive numerical study is
performed to identify optimal settings for the patch-recovery operations with
respect to computational cost and accuracy.Comment: 25 pages, 8 figures, submitted to Communications in Computational
Physic
Improving grasping forces during the manipulation of unknown objects
© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksMany of the solutions proposed for the object manipulation problem are based on the knowledge of the object features. The approach proposed in this paper intends to provide a simple geometrical approach to securely manipulate an unknown object based only on tactile and kinematic information. The tactile and kinematic data obtained during the manipulation is used to recognize the object shape (at least the local object curvature), allowing to improve the grasping forces when this information is added to the manipulation strategy.
The approach has been fully implemented and tested using the Schunk Dexterous Hand (SDH2). Experimental results are shown to illustrate the efficiency of the approach.Peer ReviewedPostprint (author's final draft
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