3,501 research outputs found
Classical particle scattering for power-law two-body potentials
We present a rigorous study of the classical scattering for anytwo-body
inter-particle potential of the form ,
with\gamma\textgreater{}0, for repulsive (g\textgreater{}0) and attractive
(g\textless{}0)interactions. We give a derivation of the complete power
series of thedeflection angle in terms of the impact factor for the weak
scatteringregime (large impact factors) as well as the asymptotic
expressionsfor the hard scattering regime (small impact factors). We see a
verydifferent qualitative and quantitative behavior depending whether
theinteraction is repulsive or attractive. In the latter case, thefamilies of
trajectories depend also strongly on the value of. We also study
carefully the modifications of the resultswhen a regularization is introduced
in the potential at small scales.We check and illustrate all the results with
the exact integration ofthe equations of motion.Comment: 23 pages, 17 figure
Geometric optics and boundary layers for Nonlinear Schrodinger equations
We justify supercritical geometric optics in small time for the defocusing
semiclassical Nonlinear Schrodinger Equation for a large class of
non-necessarily homogeneous nonlinearities. The case of a half-space with
Neumann boundary condition is also studied.Comment: 44 page
A reactive control strategy for networked hydrographical system management
A reactive control strategy is proposed to improve the water asset management of complex hydrographical systems. This strategy requires the definition of rules to achieve a generic resource allocation and setpoint assignment. A modelling method of the complex hydro- graphical network based on a weighted digraph of instrumented points, is also presented. The simulation results of the strategy applied to a hydrographical system composed of one confluent and two difluents show its efficiency and its effectiveness
On singular values decomposition and patterns for human motion analysis and simulation
We are interested in human motion characterization and automatic motion simulation. The apparent redun- dancy of the humanoid w.r.t its explicit tasks lead to the problem of choosing a plausible movement in the framework of redun- dant kinematics. This work explores the intrinsic relationships between singular value decomposition at kinematic level and optimization principles at task level and joint level. Two task- based schemes devoted to simulation of human motion are then proposed and analyzed. These results are illustrated by motion captures, analyses and task-based simulations. Pattern of singular values serve as a basis for a discussion concerning the similarity of simulated and real motions
On geodesic paths and least-cost motions for human-like tasks
We are interested in ”human-like” automatic mo- tion generation. The apparent redundancy of the humanoid wrt its explicit tasks lead to the problem of choosing a plausible movement in the framework of redundant kinematics. Some results have been obtained in the human motion literature for reach motion that involves the position of the hands. We discuss these results and a motion generation scheme associated. When orientation is also explicitly required, very few works are available and even the methods for analysis are not defined. We discuss the choice for metrics adapted to the orientation, and also the problems encountered in defining a proper metric in both position and orientation. Motion capture and simulations are provided in both cases. The main goals of this paper are : - to provide a survey on human motion features at task level for both position and orientation,
- to propose a kinematic control scheme based on these features
- to define properly the error between motion capture and automatic motion simulation
An SVD approach to reaching tasks based on cartesian geodesics
We are interested in human motion characterization and automatic motion simulation. The apparent redundancy of the humanoid w.r.t its explicit tasks lead to the problem of choosing a plausible movement in the framework of redundant kinematics. This work explores the intrinsic relationships between singular value decomposition at kinematic level and optimization principles at task level and joint level. The ideas are tested on sitting reach motions, for both translations and rotations task components
On least-cost path for realistic simulation of human motion
We are interested in "human-like" automatic motion simulation with applications in ergonomics.
The apparent redundancy of the humanoid wrt its explicit tasks leads to the problem of choosing a plausible movement in the framework of redundant kinematics.
Some results have been obtained in the human motion literature for reach motion that involves the position of the hands. We discuss these results and a motion generation scheme associated. When orientation is also explicitly required, very few works are available and even the methods for analysis are not defined.
We discuss the choice for metrics adapted to the orientation, and also the problems encountered in defining a proper metric in both position and orientation. Motion capture and simulations are provided in both cases.
The main goals of this paper are: to provide a survey on human motion features at task level for both position and orientation, to propose a kinematic control scheme based on these features, to define properly the error between motion capture and automatic motion simulation
From Vlasov-Poisson and Vlasov-Poisson-Fokker-Planck Systems to Incompressible Euler Equations: the case with finite charge
We study the asymptotic regime of strong electric fields that leads from the
Vlasov-Poisson system to the Incompressible Euler equations. We also deal with
the Vlasov-Poisson-Fokker-Planck system which induces dissipative effects. The
originality consists in considering a situation with a finite total charge
confined by a strong external field. In turn, the limiting equation is set in a
bounded domain, the shape of which is determined by the external confining
potential. The analysis extends to the situation where the limiting density is
non-homogeneous and where the Euler equation is replaced by the Lake Equation,
also called Anelastic Equation.Comment: 39 pages, 3 figure
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