scholarly journals Consistent Feature Extraction From Vector Fields: Combinatorial Representations and Analysis Under Local Reference Frames

2015 ◽  
Author(s):  
Harsh Bhatia
Keyword(s):  
Feature Extraction ◽  
Vector Fields ◽  
Reference Frames ◽  
Local Reference ◽  
Combinatorial Representations ◽  
Consistent Feature

scholarly journals Extracting Features from Time-Dependent Vector Fields Using Internal Reference Frames

2014 ◽  
Vol 33 (3) ◽  
pp. 21-30 ◽  
Author(s):  
H. Bhatia ◽  
V. Pascucci ◽  
R. M. Kirby ◽  
P.-T. Bremer
Keyword(s):  
Vector Fields ◽  
Reference Frames ◽  
Time Dependent ◽  
Internal Reference ◽  
Dependent Vector

Flexible Multibody Dynamics Based on a Fully Cartesian System of Support Coordinates

1993 ◽  
Vol 115 (2) ◽  
pp. 294-299 ◽  
Author(s):  
N. Vukasovic ◽  
J. T. Celigu¨eta ◽  
J. Garci´a de Jalo´n ◽  
E. Bayo
Keyword(s):  
Multibody Dynamics ◽  
Reference Frames ◽  
Deformable Body ◽  
Equations Of Motion ◽  
Flexible Multibody Dynamics ◽  
Body Motion ◽  
Cartesian System ◽  
Flexible Multibody ◽  
Local Reference ◽  
Rigid Multibody

In this paper we present an extension to flexible multibody systems of a system of fully cartesian coordinates previously used in rigid multibody dynamics. This method is fully compatible with the previous one, keeping most of its advantages in kinematics and dynamics. The deformation in each deformable body is expressed as a linear combination of Ritz vectors with respect to a local frame whose motion is defined by a series of points and vectors that move according to the rigid body motion. Joint constraint equations are formulated through the points and vectors that define each link. These are chosen so that a minimum use of local reference frames is done. The resulting equations of motion are integrated using the trapezoidal rule combined with fixed point iteration. An illustrative example that corresponds to a satellite deployment is presented.

scholarly journals Connection Between Non-Rotating Local Reference Frames by Means of the World Function

1991 ◽  
Vol 127 ◽  
pp. 262-265
Author(s):  
J.M. Gambi ◽  
P. Romero ◽  
A.San Miguel ◽  
F. Vicente
Keyword(s):  
Reference Frames ◽  
Riemann Tensor ◽  
Space Time ◽  
General Character ◽  
Order Of Approximation ◽  
First Order ◽  
The World ◽  
Local Reference ◽  
General Relativistic ◽  
World Function

AbstractBy means of the world function an approximate transformation showing the Riemann tensor between the Fermi coordinates associated to two non-rotating local reference frames is derived in a General Relativistic space-time. One of the observer’s world lines is resticted to be a time-like geodesic of the space-time, and the other is a time-like curve of a general character. The space-time where the transformation is evaluated is supposed to be of small curvature, and the calculations are carried out in a first order of approximation with respect to the Riemann tensor.

scholarly journals Astrometry in Local Reference Frames for Deep Space Navigation

1988 ◽  
Vol 129 ◽  
pp. 333-334
Author(s):  
R. N. Treuhaft
Keyword(s):  
Reference Frames ◽  
Local Network ◽  
Single Source ◽  
Deep Space ◽  
Space Navigation ◽  
Source Method ◽  
Long Baseline ◽  
Sample Covariance ◽  
Local Reference ◽  
Navigation Accuracy

Future deep space missions will benefit from submilliarcsecond angular navigation accuracy (< 25 km projected distance at Neptune). Conventional Very Long Baseline Interferometry (VLBI) measurement strategies entail observations of a radio source (RS) and spacecraft pair. To increase the 3–5 milliarcsecond accuracies currently attainable, instrumental improvements could be coupled with either of two methods: 1) Use improved calibration measurements with the single RS as the spacecraft reference, or 2) use a reference frame established by a local network of RS's near the spacecraft to reduce the contribution of sky-dependent error sources. The demanding baseline vector (earth orientation) and tropospheric calibrations needed to realize submilliarcsecond accuracy with the single-source strategy would not be necessary with the multi-source strategy. The two strategies are compared via a sample covariance analysis. In this analysis, the single-source method yields 1.5 milliarcseconds for the navigation accuracy, while the multi-source method yields 0.5 milliarcseconds.

The problem of conflicting reference frames when investigating three-dimensional space in surface-dwelling animals

2013 ◽  
Vol 36 (5) ◽  
pp. 564-565 ◽  
Author(s):  
Francesco Savelli ◽  
James J. Knierim
Keyword(s):  
Empirical Analysis ◽  
Reference Frames ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Local Reference ◽  
Surface Dwelling ◽  
The Impact ◽  
Experimental Strategies ◽  
Three Dimensional Space

AbstractIn a surface-dwelling animal like the rat, experimental strategies for investigating the hippocampal correlates of three-dimensional space appear inevitably complicated by the interplay of global versus local reference frames. We discuss the impact of the resulting confounds on present and future empirical analysis of the “bicoded map” hypothesis by Jeffery and colleagues.

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