Results 41 to 50 of about 878,195 (332)
An Obstacle-Avoidance Motion Planning Method for Redundant Space Robot via Reinforcement Learning
Actuators, 2023 On-orbit operation tasks require the space robot to work in an unstructured dynamic environment, where the end-effector’s trajectory and obstacle avoidance need to be guaranteed simultaneously.
Zeyuan Huang +5 more
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Reinforcement Learning-Based Reactive Obstacle Avoidance Method for Redundant Manipulators
Entropy, 2022 Redundant manipulators are widely used in fields such as human-robot collaboration due to their good flexibility. To ensure efficiency and safety, the manipulator is required to avoid obstacles while tracking a desired trajectory in many tasks ...
Yue Shen +5 more
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The Real Meaning of Complex Minkowski-Space World-Lines
, 2009 In connection with the study of shear-free null geodesics in Minkowski space, we investigate the real geometric effects in real Minkowski space that are induced by and associated with complex world-lines in complex Minkowski space.
Adamo T M +9 more
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Null surfaces in static space-times [PDF]
The European Physical Journal Plus, 2015 In this paper I consider surfaces in a space-time with a Killing vector $ ^ $ that is time-like and hypersurface orthogonal on one side of the surface. The Killing vector may be either time-like or space-like on the other side of the surface. It has been argued that the surface is null if $ _ ^ \rightarrow 0$ as the surface is approached from ...
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A New Angular Measurement in Minkowski 3-Space
Mathematics, 2020 In Lorentz−Minkowski space, the angles between any two non-null vectors have been defined in the sense of the angles in Euclidean space. In this work, the angles relating to lightlike vectors are characterized by the Frenet frame of a pseudo null ...
Jinhua Qian +3 more
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Dual Associate Null Scrolls with Generalized 1-Type Gauss Maps
Mathematics, 2020 In this work, a pair of dual associate null scrolls are defined from the Cartan Frenet frame of a null curve in Minkowski 3-space. The fundamental geometric properties of the dual associate null scrolls are investigated and they are related in terms of ...
Jinhua Qian, Xueshan Fu, Seoung Dal Jung
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On Characterizations of W-Directional Curves of Null Curves in Minkowski 4-Space
Süleyman Demirel Üniversitesi Fen-Edebiyat Fakültesi Fen Dergisi, 2022 In the present paper, we investigate the casual characterizations of W-directional curves of null curves in Minkowski 4-space. In section two, the basic concepts of curves with their Frenet equations in Minkowski 4-space are provided.
Arfah Arfah
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Null Branes in Curved Backgrounds [PDF]
, 1999 We consider null bosonic p-branes in curved space-times. Some exact solutions of the classical equations of motion and of the constraints for the null membrane in general stationary, axially symmetrical, four dimensional, gravity background are found ...
D. Kramer +10 more
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Role of Z-pinches in magnetic reconnection in space plasmas
, 2014 A widely accepted scenario of magnetic reconnection in collisionless space plasmas is the breakage of magnetic field lines in X-points. In laboratory, reconnection is commonly studied in pinches, current channels embedded into twisted magnetic fields. No
Divin, Andrey +3 more
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Chebyshev approximation with a null space [PDF]
Proceedings of the American Mathematical Society, 1973 Chebyshev approximation involving continuous functions vanishing on a closed set V V is considered. The approximating families studied have the betweenness property. Examples are given of such families. A necessary and sufficient condition for uniqueness of best approximations is obtained.
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