Baselines for three-dimensional perception of combined linear and angular self-motion with changing rotational axis

2000 ◽  
Vol 10 (4-5) ◽  
pp. 163-178
Author(s):  
Jan E. Holly
Keyword(s):  
Three Dimensional ◽  
Angular Acceleration ◽  
Three Dimensions ◽  
Whole Body ◽  
Rotational Axis ◽  
Clockwise Rotation ◽  
Acceleration And Deceleration ◽  
The Subject ◽  
Initial Perception ◽  
Self Motion

The laws of physics explain many human misperceptions of whole-body passive self-motion. One classic misperception occurs in a rotating chair in the dark: If the chair is decelerated to a stop after a period of counterclockwise rotation, then a subject will typically perceive clockwise rotation. The laws of physics show that, indeed, a clockwise rotation would be perceived even by a perfect processor of angular acceleration information, assuming that the processor is initialized (prior to the deceleration) with a typical subject's initial perception – of no rotation in this case. The motion perceived by a perfect acceleration processor serves as a baseline by which to judge human self-motion perception; this baseline makes a rough prediction and also forms a basis for comparison, with uniquely physiological properties of perception showing up as deviations from the baseline. These same principles, using the motion perceived by a perfect acceleration processor as a baseline, are used in the present paper to investigate complex motions that involve simultaneous linear and angular accelerations with a changing axis of rotation. Baselines – motions that would be perceived by a perfect acceleration processor, given the same initial perception (prior to the motion of interest) as that of a typical subject – are computed for the acceleration and deceleration stages of centrifuge runs in which the human carriage tilts along with the vector resultant of the centripetal and gravity vectors. The computations generate a three-dimensional picture of the motion perceived by a perfect acceleration processor, by simultaneously using all six interacting degrees of freedom (three angular and three linear) and taking into account the non-commutativity of rotations in three dimensions. The resulting three-dimensional baselines predict stronger perceptual effects during deceleration than during acceleration, despite the equal magnitudes (with opposite direction) of forces on the subject during acceleration and deceleration. For a centrifuge run with the subject facing tangentially in the direction of motion, the deceleration baseline shows a perception of forward tumble (pitch rotation) beginning with ascent from the earth, while the acceleration baseline does not have analogous pitch and vertical motion. These results give a three-dimensional explanation for certain puzzling acceleration-deceleration perceptual differences observed experimentally by Guedry, Rupert, McGrath, and Oman (Journal of Vestibular Research, 1992 (2).). The present analysis is consistent with, and expands upon, previous analyses of individual components of motion.

Self-motion perception during conflicting visual-vestibular acceleration

2009 ◽  
Vol 18 (5-6) ◽  
pp. 267-272
Author(s):  
Masayuki Ishida ◽  
Hiroaki Fushiki ◽  
Hiroshi Nishida ◽  
Yukio Watanabe
Keyword(s):  
Visual Information ◽  
Angular Acceleration ◽  
Vertical Axis ◽  
The Body ◽  
Whole Body ◽  
Large Field ◽  
Constant Acceleration ◽  
Conflicting Information ◽  
The Subject ◽  
Self Motion

Self-motion is known to be falsely perceived during exposure to the movement of visual surroundings. This illusory perception of visually-induced self-motion is known as "vection." The present study was conducted to examine the relative strengths of vection versus whole-body angular acceleration as they determine perceived self-rotation under conditions in which they individually provide conflicting information. Each subject was rotated for 90 s about a vertical axis at a constant acceleration, and a large-field visual surround in front of the subject was simultaneously rotated at a constant acceleration in the same direction, but at a magnitude of acceleration twice that of the body. This stimulus condition creates a sensory conflict between information from the vestibular/somatosensory systems and information from the visual system with respect to the direction of self-rotation. The subject eventually perceived self-acceleration in the direction of circular vection (CV), even though he or she was actually being accelerated in the direction opposite to CV. When the magnitude of contradictory chair acceleration exceeded the vestibular perceptual threshold, the onset latency of CV was significantly delayed. Our results suggest that visual information contributes to the perception of self-acceleration, and that illusory self-motion could overwhelm the feeling of self-acceleration due to inertial motion. CV would thus be a significant factor in determining spatial orientation in certain operational environments and flight conditions.

scholarly journals Biases in the perception of self-motion during whole-body acceleration and deceleration

2013 ◽  
Vol 7 ◽  
Author(s):  
Luc Tremblay ◽  
Andrew Kennedy ◽  
Dany Paleressompoulle ◽  
Liliane Borel ◽  
Laurence Mouchnino ◽  
...  
Keyword(s):  
Whole Body ◽  
Body Acceleration ◽  
Acceleration And Deceleration ◽  
Perception Of Self ◽  
Self Motion

Validation of the Spanish Version of the School Engagement Measure (SEM)

2016 ◽  
Vol 19 ◽  
Author(s):  
Estibaliz Ramos-Díaz ◽  
Arantzazu Rodríguez-Fernández ◽  
Lorena Revuelta
Keyword(s):  
School Engagement ◽  
Basque Country ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Dimensional Structure ◽  
Emotional Engagement ◽  
Future Research ◽  
Confirmatory Factor ◽  
The Subject ◽  
Language Measures

AbstractThe scientific study of school engagement has recently been the subject of considerable interest in the field of educational psychology, and significant advances have been made in our knowledge of this construct. For instance, there is currently consensus in the scientific community that it is multifaceted, and has three dimensions: behavioral engagement, emotional engagement, and cognitive engagement. However, more advanced statistical analyses are needed to validate Spanish-language measures of school engagement, which this study proposes to do. The sample was comprised of 1,250 adolescents from Basque Country (49% boys, 51% girls) aged 12 to 15 years old (M = 13.72, SD = 1.09). The results of confirmatory factor analysis on the School Engagement Measure (Fredricks, Blumenfeld, Friedel, & Paris, 2005) supported a three-dimensional structure of school engagement (χ2(100) = 676.93, p < .001; GFI = .931; CFI = .906; IFI = .907; SRMR = .058; RMSEA = .068). Reliability indexes were satisfactory, ranging from .83 to .94. Adequate evidence of concurrent validity was found for the variable perceived school performance (p < .01). The results are discussed from an educational perspective, and with an eye to future research.

Angle-Based Drawing Accuracy Analysis and Mental Models of Three-Dimensional Space

2014 ◽  
Vol 2 (1-2) ◽  
pp. 183-212 ◽  
Author(s):  
Linda Carson ◽  
Nadine Quehl ◽  
Inara Aliev ◽  
James Danckert
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Objective Measure ◽  
Ground Truth ◽  
Three Dimensions ◽  
Still Life ◽  
Visuomotor Task ◽  
3D Space ◽  
Perspective Drawing ◽  
The Subject

Drawing from a still-life is a complex visuomotor task. Nevertheless, experts depict three-dimensional subjects convincingly with two-dimensional images. Studies of drawing have historically relied on human critics’ judgement of the drawings, the professional reputations and self-reported experience of the drawers. To extend that work, we developed an objective measurement of the accuracy of a perspective drawing, based on a comparison of the drawing with a ground truth photograph of the subject taken from the same viewpoint. If we measure the angles at intersecting edges in the drawings we can calculate both local errors and each person’s mean percentage magnitude error across angles in the still life. This gives a continuous objective measure of drawing accuracy that correlates well with years of art experience. Drawing expertise may depend to some extent on more accurate internal models of 3D space. To explore this possibility we had adults with a range of drawing experience draw a still life. Participants also made perceptual judgements of still lifes, both from direct observation and from an imagined side view. A conventional mental rotation task failed to differentiate drawing expertise. However, those who drew angles more accurately were also significantly better judges of slant, i.e., the pitch of edges in the still life. Those with the most drawing experience were significantly better judges of spatial extent, i.e., which landmarks were leftmost, rightmost, nearest, farthest etc. The ability to visualize in three dimensions the orientation and relationships of components of a still life predicts drawing accuracy and expertise.

“Grid-mapped” freeze-fracture: Three-Dimensional confocal laser scanning microscopy for directed fracturing and histological mapping of neurons in spinal cord and brain

1993 ◽  
Vol 51 ◽  
pp. 64-65
Author(s):  
J. E. Rash ◽  
L. R. Whalen ◽  
P. B. Guthrie ◽  
M. Morita ◽  
R. Dillman ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Laser Scanning Microscopy ◽  
Three Dimensions ◽  
Male Rats ◽  
Whole Body ◽  
Confocal Laser ◽  
Fracture Plane

A new correlative microscopic technique, “grid-mapped” freeze fracture, is introduced. This technique allows individual cells in histological slices to be freeze fractured, and their ultrastructural details to be correlated with conventional histological and gross anatomical features. Adult male rats were anesthetized, the sciatic nerve was exposed and crushed, and rhodaminefilled latex microspheres (Lumafluor, Inc) were injected at the crush site to label motor neurons. After 3-7 days, rats were fixed by whole-body perfusion. The brains and spinal cords were removed, embedded in 5% gelatin, and 50 or 100 μm thick slices were cut with a Vibratome. Slices were mapped in three-dimensions (Figs. 1-2 and 3-4) using a Molecular Dynamics Multiport 2001 confocal microscope, and the depths of selected cells were measured (±2μm) from the cut surfaces. After freezing on gold specimen supports, the fracture plane was directed through selected neurons using the precise planar microtome of the JEOL JFD-9000-CR freeze-fracture machine.

Perceptual disturbances predicted in zero-g through three-dimensional modeling

2003 ◽  
Vol 13 (4-6) ◽  
pp. 173-186
Author(s):  
Jan E. Holly
Keyword(s):  
Three Dimensional ◽  
Head Tilt ◽  
Three Dimensions ◽  
Coriolis Effect ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Coupled Effect ◽  
The Subject ◽  
Axis Rotation

Perceptual disturbances in zero-g and 1-g differ. For example, the vestibular coriolis (or "cross-coupled") effect is weaker in zero-g. In 1-g, blindfolded subjects rotating on-axis experience perceptual disturbances upon head tilt, but the effects diminish in zero-g. Head tilts during centrifugation in zero-g and 1-g are investigated here by means of three-dimensional modeling, using a model that was previously used to explain the zero-g reduction of the on-axis vestibular coriolis effect. The model's foundation comprises the laws of physics, including linear-angular interactions in three dimensions. Addressed is the question: In zero-g, will the vestibular coriolis effect be as weak during centrifugation as during on-axis rotation? Centrifugation in 1-g was simulated first, with the subject supine, head toward center. The most noticeable result concerned direction of head yaw. For clockwise centrifuge rotation, greater perceptual effects arose in simulations during yaw counterclockwise (as viewed from the top of the head) than for yaw clockwise. Centrifugation in zero-g was then simulated with the same "supine" orientation. The result: In zero-g the simulated vestibular coriolis effect was greater during centrifugation than during on-axis rotation. In addition, clockwise-counterclockwise differences did not appear in zero-g, in contrast to the differences that appear in 1-g.

Matter Tensors and Coordinate Transformations

1996 ◽  
Author(s):  
Gerhard Oertel
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Coordinate Transformations ◽  
Ordered Arrays ◽  
The Subject ◽  
Three Dimensional Space ◽  
Three Components

Vectors, the subject of the previous two chapters, may be classified as members of a class of mathematical entities called tensors, insofar as they can be expressed in the form of ordered arrays, or matrices, and insofar as they further conform to conditions to be explored in the present chapter. Tensors can have various ranks, and vectors are tensors of the first rank, which in three-dimensional space have 31 or three components. Much of this, and later, chapters deals with tensors of the second rank which in the same space have 32 or nine components. Tensors of higher (nth) rank do exist and have 3n components, and so do, at least nominally, tensors of zero rank with a single, or 30, component, which makes them scalars. Tensors of the second rank for three dimensions are written as three-by-three matrices with each component marked by two subscripts, which may be either letters or numbers.

scholarly journals Math Learning Problematics on the Subject of 3D Topics

2020 ◽  
Vol 3 ◽  
pp. 341-345
Author(s):  
Hega Narimoati ◽  
Annisa Fitriani ◽  
Ahmad Faris Alfiyansah ◽  
Meli `Handayani
Keyword(s):  
Creative Thinking ◽  
Mathematical Reasoning ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Thinking Skills ◽  
Three Dimensions ◽  
Reasoning Ability ◽  
Ability Test ◽  
Study Approach ◽  
The Subject

In the 21st century, the ability to be mastered by students is increasingly complex, such as the ability of critical thinking, creative thinking skills, communication skills, ability to cooperate, as well as ability in reasoning. The ability of reasoning in students is crucial to learn and develop. The reasoned ability is not only needed when studying mathematics but is indispensable when determining decisions in life. The instrument in this study is how the mathematical reasoning process of students is low, moderate and high on the subject matter of three dimensions. The study aims to know students' learning difficulties relating to the students' mathematical reasoning ability on surface area material and the volume of three-dimensional space. This research is a qualitative descriptive study with a case study approach. The subject of this study involved 30 students. The instrument in this research is a mathematical reasoning ability test. The results showed that 40% of students had high reasoning ability, 40% of students had moderate reasoning ability, and 20% had low reasoning ability. Students with high reasoning ability have no significant difficulty in completing the instrument in this study, students with reasoning ability are having difficulty in calculating and interpreting the intent of the question, and students with low reasoning ability have difficulty in drafting a completion plan. The study concluded that the students' reasoning ability on the three-dimensional material belongs to the medium category.

Three Dimensional Eye Movements of Squirrel Monkeys Following Postrotatory Tilt

1993 ◽  
Vol 3 (2) ◽  
pp. 123-139 ◽  
Author(s):  
Daniel M. Merfeld ◽  
Laurence R. Young ◽  
Gary D. Paige ◽  
David L. Tomko
Keyword(s):  
Eye Movements ◽  
Time Course ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Head Orientation ◽  
Ocular Reflex ◽  
Eye Rotation ◽  
Acceleration And Deceleration ◽  
Vestibulo Ocular Reflex ◽  
Vertical Nystagmus

Three-dimensional squirrel monkey eye movements were recorded during and immediately following rotation around an earth-vertical yaw axis (160∘/s steady state, 100∘/s2 acceleration and deceleration). To study interactions between the horizontal angular vestibulo-ocular reflex (VOR) and head orientation, postrotatory VOR alignment was changed relative to gravity by tilting the head out of the horizontal plane (pitch or roll tilt between 15∘ and 90∘) immediately after cessation of motion. Results showed that in addition to post rotatory horizontal nystagmus, vertical nystagmus followed tilts to the left or right (roll), and torsional nystagmus followed forward or backward (pitch) tilts. When the time course and spatial orientation of eye velocity were considered in three dimensions, the axis of eye rotation always shifted toward alignment with gravity, and the postrotatory horizontal VOR decay was accelerated by the tilts. These phenomena may reflect a neural process that resolves the sensory conflict induced by this postrotatory tilt paradigm.

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