Stiffness Mappings Employing Different Frames of Reference

1992 ◽  
Author(s):  
T. Pigoski ◽  
M. Griffis ◽  
J. Duffy
Keyword(s):  
Reference Frames ◽  
Compliant Mechanism ◽  
Hessian Matrix ◽  
Frame Of Reference ◽  
The Other ◽  
Frames Of Reference ◽  
Static Force ◽  
Moving Body ◽  
Elastic Potential Energy ◽  
Work Done

Abstract The stiffness mapping matrix for a planar compliant mechanism is analyzed using two different reference frames. The first is rigidly attached to the fixed body of the coupling, whilst the second is attached to the moving body of the coupling. It was found that, in general, these matrices are asymmetric when the coupling is loaded, and that one is the transpose of the other. This is an important result and can be considered an extension of the work done by Dimentberg[1], who derived a symmetrical stiffness mapping for an unloaded coupling. These new mappings are essential for the control of the coupling as it moves away from its unloaded position. Additionally, a third frame of reference which produces a symmetric mapping is examined and found to be identical to the Hessian matrix obtained from the second differentials of the elastic potential energy of the system. However, this symmetric mapping is not useful for control purposes and is only included to show that such a frame can be realized. Finally, static force loci for each of the reference frames are drawn to support the notion of frame-of-reference dependency.

scholarly journals Classical Absolute/Differential Programs

1986 ◽  
Vol 7 ◽  
pp. 77-80
Author(s):  
L V Morrison
Keyword(s):  
Solar System ◽  
Ab Initio ◽  
Reference Frames ◽  
Mechanical Systems ◽  
The Other ◽  
Frames Of Reference ◽  
Rotating Frame ◽  
Absolute Differential ◽  
The Galaxy

In astronomy we try to determine a non-rotating frame from analyses of the observed motions of three mechanical systems – the solar system, the galaxy and the extragalactic nebulae. The rotation of the extragalactic frame is of the order 10-10 arcsec per century, so, for all practical purposes, this frame may be regarded as having no rotation. The other two frames are model-dependent and, as such, cannot be regarded ab initio as constituting non-rotation frames of reference. These reference frames are linked by various techniques, as shown in the diagram below.

Object-Centered Neglect in Patients with Unilateral Neglect: Effects of Left-Right Coordinates of Objects

1994 ◽  
Vol 6 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Marlene Behrmann ◽  
Morris Moscovitch
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Frame Of Reference ◽  
The Other ◽  
Unilateral Neglect ◽  
Independent Measure ◽  
Object Based ◽  
Spatial Coordinates ◽  
Left And Right

When patients with right-sided hemispheric lesions neglect information on the left side, with respect to what set of spatial coordinates is left defined? Two potential reference frames were examined in this study, one where left and right are defined with respect to the midline of the viewer and/or environment (viewer/env-centered) and the other where left and right are defined with respect to the midline of the object (object-centered). By rotating the stimulus 90° clockwise or counterclockwise, and instructing patients with neglect to report the colors appearing around the border of a stimulus, an independent measure was obtained for the number of colors reported from the left and right of the viewer/env- and from the object-based reference frame. Whereas significant object-centered neglect was observed only for upper case asymmetrical letters but not for symmetrical letters nor for drawings of familiar animals or objects, significant viewer/env-based neglect was observed with all the stimulus types. We present an account of the coexistence of neglect in more than one frame of reference and the presence of object-centered neglect under a restricted set of conditions.

Relationship between Frames of Reference and Mirror-Image Reversals

Perception ◽  
10.1068/p5529 ◽  
2007 ◽  
Vol 36 (7) ◽  
pp. 1049-1056 ◽  
Author(s):  
Hirokazu Yoshimura ◽  
Tatsuo Tabata
Keyword(s):  
Mirror Image ◽  
Frame Of Reference ◽  
The Other ◽  
Frames Of Reference ◽  
Physical Aspect ◽  
Other Hand ◽  
Extended Problem ◽  
Left Right Asymmetry ◽  
Common Frame Of Reference ◽  
Intrinsic Frame

The mirror puzzle related to the perception of mirror images as left–right reversed can be more fully understood by considering an extended problem that includes also the perception of mirror images that are not left–right reversed. The purpose of the present study is to clarify the physical aspect of this extended problem logically and parsimoniously. Separate use of the intrinsic frame of reference that belongs to the object and one that belongs to its mirror image always leads to the perception of left–right reversal when the object has left–right asymmetry; on the other hand, the perception of left–right nonreversal is always due to the application of a common frame of reference to the object and its mirror image.

scholarly journals Modes of pointing to existing spaces and the use of frames of reference

Gesture ◽  
2011 ◽  
Vol 11 (3) ◽  
pp. 271-307 ◽  
Author(s):  
Olivier Le Guen
Keyword(s):  
Frame Of Reference ◽  
Point Of View ◽  
The Body ◽  
The Other ◽  
Frames Of Reference ◽  
Spatial Relationships ◽  
External Cues ◽  
The Status ◽  
Systematic Framework

This paper aims at providing a systematic framework for investigating differences in how people point to existing spaces. Pointing is considered according to two conditions: (1) A non-transposed condition where the body of the speaker always constitutes the origo and where the various types of pointing are differentiated by the status of the target and (2) a transposed condition where both the distant figure and the distant ground are identified and their relation specified according to two frames of reference (FoRs): the egocentric FoR (where spatial relationships are coded with respect to the speaker’s point of view) and the geocentric FoR (where spatial relationships are coded in relation to external cues in the environment). The preference for one or the other frame of reference not only has consequences for pointing to real spaces but has some resonance in other domains, constraining the production of gesture in these related domains.

New visuomotor maps are immediately available to the opposite limb

2014 ◽  
Vol 111 (11) ◽  
pp. 2232-2243 ◽  
Author(s):  
Timothy J. Carroll ◽  
Eugene Poh ◽  
Aymar de Rugy
Keyword(s):  
Reference Frames ◽  
Neural Circuits ◽  
Index Finger ◽  
Visual Display ◽  
The Other ◽  
Frames Of Reference ◽  
Visuomotor Transformations ◽  
Brain Circuits ◽  
Partial Transfer ◽  
Opposite Limb

Humans can learn to make accurate movements when the required map between vision and motor commands changes, but can visuomotor maps obtained through experience with one limb benefit the other? Complete transfer would require new maps to be both fully compatible and accessible between limbs. However, when this question is addressed by providing subjects with rotated visual feedback during reaching, transfer is rarely apparent in the first few trials with the unpracticed limb and is sometimes absent altogether. Partial transfer might be explained by limited accessibility to remapped brain circuits, since critical visuomotor transformations mediating unilateral movements appear to be lateralized. Alternatively, if adaptation involves movement representations associated with both extrinsic (i.e., direction of motion in space) and intrinsic (i.e., joint or muscle based) frames of reference, new visuomotor maps might be incompatible with opposite limb use when visual distortions have opposite effects for the two limbs in intrinsic coordinates. Here we addressed this issue when subjects performed an isometric aiming task with the index finger. We manipulated the alignment of visuomotor distortion for the two hands in different reference frames by altering body posture relative to the orientation of the finger and the visual display. There was strong, immediate transfer of adaptation between limbs only when visuomotor distortion had identical effects in eye- and joint-based coordinates bilaterally. This implies that new visuomotor maps are encoded in neural circuits associated with both intrinsic and extrinsic movement representations and are available to both limbs.

Collections of Memory Institutions: New Trends for Research

2012 ◽  
Vol 2 ◽  
pp. 9-18
Author(s):  
Arvydas Pacevičius
Keyword(s):  
Cultural Theory ◽  
Interdisciplinary Approach ◽  
Frame Of Reference ◽  
The Other ◽  
Systematic Research ◽  
Library History ◽  
Modern Library ◽  
Research Paradigms ◽  
Theoretical Perspectives ◽  
New Research

The publication features information on research done during the Bibliotheca Lituana project. In particular the focus is on collections of memory institutions, new perspectives on library and other memory institution, i.e. archives, museums, research. Modern library history has adopted relevant theoretical perspectives from social and cultural theory. Currently these perspectives incorporate not only the activities and collections of the aforementioned institutions but also the more widely interpreted information infrastructure, that do not have libraries as their main frame of reference. Problems faced publishing archival sources are also examined. It was determined that insufficient attention is given to research and publication of old catalogues, inventories and book listings. On the other hand a unified system and methodology for publishing of the aforementioned sources does not exist. We come to a conclusion that through new research paradigms, an interdisciplinary approach and change of thought in the archival, librarian and museology communities, we can start systematic research of libraries and other memory institutions. Their results would complement the pages of the continued Bibliotheca Lituana publications.

COMPUTING THE RUPTURE DEGREE IN COMPOSITE GRAPHS

2010 ◽  
Vol 21 (03) ◽  
pp. 311-319 ◽  
Author(s):  
AYSUN AYTAC ◽  
ZEYNEP NIHAN ODABAS
Keyword(s):  
Complete Graph ◽  
Connected Graph ◽  
The Other ◽  
Trade Off ◽  
Number Of Components ◽  
Np Complete ◽  
Work Done ◽  
Better Than

The rupture degree of an incomplete connected graph G is defined by [Formula: see text] where w(G - S) is the number of components of G - S and m(G - S) is the order of a largest component of G - S. For the complete graph Kn, rupture degree is defined as 1 - n. This parameter can be used to measure the vulnerability of a graph. Rupture degree can reflect the vulnerability of graphs better than or independent of the other parameters. To some extent, it represents a trade-off between the amount of work done to damage the network and how badly the network is damaged. Computing the rupture degree of a graph is NP-complete. In this paper, we give formulas for the rupture degree of composition of some special graphs and we consider the relationships between the rupture degree and other vulnerability parameters.

Obliquity Integration: Variations on a Theme of Delbœuf

Perception ◽  
1993 ◽  
Vol 22 (6) ◽  
pp. 705-712
Author(s):  
Giovanni B Vicario ◽  
Giulio Vidotto ◽  
Elena Zambianchi
Keyword(s):  
Frame Of Reference ◽  
The Other ◽  
Geometrical Illusion ◽  
Tilt Illusion ◽  
Variations On A Theme ◽  
Rod And Frame

An optical—geometrical illusion, described by Delbœuf and not familiar to specialists, is investigated. The results of two experiments show that the divergence between a bar filled with parallel slanting lines and a line drawn above it is clearly related to this angle of the lines which fill the bar. The illusion is already present when this angle is 10°, reaches its maximum at 20°, decreases at 30°, and almost disappears at 40°. These results are similar to those found for the tilt illusion, are slightly different from those found for the rod-and-frame illusion, and differ greatly from those found for the Zöllner illusion. The other variables considered—the distance between the slanting lines filling up the bar, the distance between the upper line and the bar, and the width of the bar—do not influence the illusion as much. Since either the line appears as diverging from the bar, or the bar seems inclined in relation to the line, the illusion should be considered a complex one. The small oblique lines inside the bar induce obliquity in the opposite sense in the display, but which of the elements is seen as diverging from the other depends on which of the two is established as the frame of reference.

scholarly journals The principle of canonical orientation: a cross-linguistic study

2018 ◽  
Vol 10 (3) ◽  
pp. 494-513 ◽  
Author(s):  
ALI ALSHEHRI ◽  
JUERGEN BOHNEMEYER ◽  
RANDI MOORE ◽  
GABRIELA PÉREZ BÁEZ
Keyword(s):  
Regression Models ◽  
Reference Frames ◽  
Frames Of Reference ◽  
Canonical Orientation ◽  
Linguistic Study ◽  
Ground Object ◽  
Canonical Position

abstractThis paper presents a cross-linguistic investigation of a constraint on the use on intrinsic frames of reference proposed by Levelt (1984, 1996). This proposed constraint claims that use of intrinsic frames when the ground object is in non-canonical position is blocked due to conflict with gravitational-based reference frames. Regression models of the data from Arabic, K’iche’, Spanish, Yucatec, and Zapotec suggest that this constraint is valid across languages. However, the strength at which the constraint operates is predicted by the frequency of canonical intrinsic frames in the particular language. The ratio of the incidence of intrinsic usage with canonical vs. non-canonical orientation appears to be remarkably uniform across languages, which suggests the possibility of a strong cognitive universal.

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