Flexible needle insertion into viscoelastic tissue is modeled in this paper with a linear beam supported by virtual springs. Using this simplified model, the forward and inverse kinematics of the needle is solved analytically, providing a way for simulation and path planning in real-time. Using the inverse kinematics, the required needle basis trajectory can be computed for any desired needle t...

Stochastic simulation of facies or geologic units is important before the assignment of continuous rock properties. Sequential indicator simulation (SIS) remains a reasonable approach when there are no clear genetic shapes that could be put into object-based modeling. Constraining SIS to soft secondary data coming from geological interpretation or geophysical measurements is important. There ar...

i Acknowledgements ii Table of

We study hard exclusive electroproduction of two pions in the QCD factorization approach at next-to-leading order (NLO) in the strong coupling. The pion pair can be produced both in an isovector and in an isoscalar state. The angular distribution of the produced pion pairs allows one to project out a component that depends on the interference of the isovector and isoscalar channels. Using speci...

In many practical situations, users select between n alternatives a1, . . . , an, and the only information that we have about the utilities vi of these alternatives are bounds vi ≤ vi ≤ vi. In such situations, it is reasonable to assume that the values vi are independent and uniformly distributed on the corresponding intervals [vi, vi]. Under this assumption, we would like to estimate, for each...

This paper aims at describing a new method to simulate the locomotion of hemiplegic subjects. To this end, we propose to use inverse kinematics in order to make the feet follow a trajectory with respect to the root frame linked to the pelvis. The 11 degrees of freedom are then retrieved by inversing the kinematic function while taking other constraints into account. These constraints, termed se...

We present an analysis of the space motions of 742 subdwarf stars based on the sample of Carney et al.(1994). Hipparcos parallaxes, TYC2+HIP proper motions and Tycho2 proper motions were combined with radial velocities and metallicities from CLLA. The kinematical behavior is discussed in particular in relation to their metallicities. The majority of these sample stars have metal abundances of [...

Instantaneous kinematics and singularity analysis of a class of three-legged, 6-DOF parallel manipulators are addressed in this paper. A generic method of derivation of reciprocal screw and consequently, the instantaneous kinematics model is presented. The advantage of this formulation is that the instantaneous kinematics model possesses well-defined geometric meaning and algebraic structure. S...

Special Relativity (SR) kinematics is derived from very intuitive assumptions. Contrary to standard Einstein’s derivation, no light signal is used in the construction nor it is assumed to exist. Instead we postulate the existence of two equivalence classes of physical objects: proportional clocks and proportional rulers. Simple considerations lead to Lorentz kinematics as one of three generic c...

Invariant methods for formulating and analying the mechanics of the skeleto-muscular system with geometric algebra are further developed and applied to reaching kinematics. This work is set in the context of a neurogeometry research program to develop a coherent mathematical theory of neural sensory-motor control systems.