Alleys on an Extensive Apparent Frontoparallel Plane: A Second Experiment

Perception ◽  
1988 ◽  
Vol 17 (5) ◽  
pp. 647-666 ◽  
Author(s):  
Tarow Indow ◽  
Toshio Watanabe
Keyword(s):  
Depth Perception ◽  
Horizontal Plane ◽  
Physical Space ◽  
Visual Space ◽  
Vertical Separation ◽  
Frontoparallel Plane ◽  
Mapping Functions ◽  
The Subject ◽  
Left And Right ◽  
Striking Contrast

Small light points were presented, in the dark, around a point in the center which was fixed at a distance of about 3 m from the subject. In experiment 1, the subject adjusted the positions of points so that all were frontoparallel and in three horizontal series, each consisting of five points, with the middle series level with the eyes, to satisfy the following conditions: (i) the three series must appear straight and horizontally parallel; (ii) the points of each of the five triplets must appear equally separated vertically; (iii) the three points of each triplet must appear to move horizontally along straight and parallel paths; (iv) the three points of each triplet must appear to move horizontally with a constant vertical separation. The most distant points were about 0.51 rad to the left and right of center, and about 0.22 rad above and below. In experiment 2, with the configuration of points obtained in experiment 1, the subject assessed ratios of all perceptual distances between points and also from the subject to all points. From experiment 1 (three subjects used), Gaussian curvature K and a constant related to depth perception (σ) were estimated under the assumption that the frontoparallel plane is a Riemannian plane of constant curvature K and that Luneburg's mapping functions between visual space and physical space hold. The analysis was made according to equations different from those used previously. The results of experiment 2 (two subjects used) were analyzed by a new computer program in which no preassumed mapping functions are necessary for the estimation of K. From both analyses it is clear that there is no need to assume any other value of K than 0 (Euclidean) to describe the geometry of the frontoparallel plane. This presents a striking contrast to the results from experiments on parallel and equidistance alleys running toward the subject on the horizontal plane.

Errors in Estimating the Orientation of Dot Patterns

Perception ◽  
1989 ◽  
Vol 18 (2) ◽  
pp. 237-242 ◽  
Author(s):  
P Lánský ◽  
Naum Yakimoff ◽  
T Radil ◽  
L Mitrani
Keyword(s):  
Pattern Analysis ◽  
Frontoparallel Plane ◽  
The Subject ◽  
Left And Right ◽  
The Mean ◽  
The Difference

The error in estimating the orientation of a dot pattern was measured as the difference between the orientation of the least-squared-distances line (LS-line) of the pattern and the orientation of a line adjusted by the subject to match the perceived orientation of the pattern. Analysis of the mean errors (averaged over ten subjects) obtained for one hundred patterns confirmed that the orientation of the LS-line represents the orientation of elongated dot-patterns. It is shown that estimated orientation was systematically biased towards the nearest 45° oblique meridian. This bias points to the importance of the ±45° directions as natural norms for left- and right-side tilt in the frontoparallel plane.

scholarly journals One-Dimensional and Multi-Dimensional Studies of the Exocentric Distance Estimates in Frontoparallel Plane, Virtual Space, and Outdoor Open Field

2006 ◽  
Vol 9 (2) ◽  
pp. 273-284 ◽  
Author(s):  
J. Antonio Aznar-Casanova ◽  
Elton H. Matsushima ◽  
Nilton P. Ribeiro-Filho ◽  
José A. Da Silva
Keyword(s):  
Open Field ◽  
Visual Cues ◽  
Physical Space ◽  
Visual Space ◽  
Virtual Space ◽  
Coefficient Of Determination ◽  
Frontoparallel Plane ◽  
Field Range ◽  
Exocentric Distance ◽  
Scaling Analyses

The aim of this study is twofold: on the one hand, to determine how visual space, as assessed by exocentric distance estimates, is related to physical space. On the other hand, to determine the structure of visual space as assessed by exocentric distance estimates. Visual space was measured in three environments: (a) points located in a 2-D frontoparallel plane, covering a range of distances of 20 cm; (b) stakes placed in a 3-D virtual space (range ≈ 330 mm); and (c) stakes in a 3-D outdoors open field (range = 45 m). Observers made matching judgments of distances between all possible pairs of stimuli, obtained from 16 stimuli (in a regular squared 4 × 4 matrix). Two parameters from Stevens' power law informed us about the distortion of visual space: its exponent and its coefficient of determination (R2). The results showed a ranking of the magnitude of the distortions found in each experimental environment, and also provided information about the efficacy of available visual cues of spatial layout. Furthermore, our data are in agreement with previous findings showing systematic perceptual errors, such as the further the stimuli, the larger the distortion of the area subtended by perceived distances between stimuli. Additionally, we measured the magnitude of distortion of visual space relative to physical space by a parameter of multidimensional scaling analyses, the RMSE. From these results, the magnitude of such distortions can be ranked, and the utility or efficacy of the available visual cues informing about the space layout can also be inferred.

scholarly journals Clarifying the Structure and Nature of Left-Wing Authoritarianism

2020 ◽  
Author(s):  
Thomas H Costello ◽  
Shauna Bowes ◽  
Sean T. Stevens ◽  
Irwin Waldman ◽  
Scott O. Lilienfeld
Keyword(s):  
Political Violence ◽  
Scientific Inquiry ◽  
Data Driven ◽  
Right Wing ◽  
Left Wing ◽  
Nomological Network ◽  
Right Wing Authoritarianism ◽  
Beliefs And Values ◽  
The Subject ◽  
Left And Right

Authoritarianism has been the subject of scientific inquiry for nearly a century, yet the vast majority of authoritarianism research has focused on right-wing authoritarianism. In the present studies, we investigate the nature, structure, and nomological network of left-wing authoritarianism (LWA), a construct famously known as “the Loch Ness Monster” of political psychology. We iteratively construct a measure and data-driven conceptualization of LWA across six samples (N = 7,258) and conduct quantitative tests of LWA’s relations with over 50 authoritarianism-related variables. We find that left- and right-wing authoritarianism reflect a shared constellation of personality traits, cognitive features, beliefs, and values that might be considered the “heart” of authoritarianism. Our results also indicate that LWA powerfully predicts several critical, real-world outcomes, including participation in political violence. We conclude that a movement away from exclusively right-wing conceptualizations of authoritarianism may be required to illuminate authoritarianism’s central features, conceptual breadth, and psychological appeal.

The Effect of the Operator's Handedness on Some Directional Stereotypes in Control-Display Relationships

1968 ◽  
Vol 10 (4) ◽  
pp. 303-320 ◽  
Author(s):  
Alphonse Chapanis ◽  
Bernard A. Gropper
Keyword(s):  
Initial Direction ◽  
Clockwise Rotation ◽  
Control Knob ◽  
Left Handed ◽  
Common Control ◽  
Direction Of Movement ◽  
The Subject ◽  
Left And Right ◽  
Vertical Scales

Recommendations about preferred directions of movement for controls and displays are based almost exclusively on right-handed persons. This experiment has studied some common control-display movement stereotypes to find out if these stereotypes are equally valid for left- and right-handed subjects. Our apparatus presented a scale that could be oriented horizontally or vertically. The numbers on the scale increased either right-to-left or left-to-right for the horizontal scales, or up-to-down or down-to-up for the vertical scales. The linkage between the movement of a control knob and the movement of the hairline on the scale was reversible so that a clockwise rotation of the knob could be made to move the hairline toward either end of the scale. We recorded (1) the direction of the first movement made by the subject on each trial, (2) the total number of reversal movements made on each setting, (3) the time taken to make a setting, and (4) the actual setting made (and so, of course, setting errors). We tested 64 subjects, 32 left-handed and 32 right-handed, each using his preferred and non-preferred hands. Significant differences were found in the time to make settings, the number of reversal movements, and errors in initial direction of movement as functions of handedness and the various apparatus relationships. In addition to overall differences between the performance of the left- and right-handed subjects, the two groups behaved differently on some measures when using their preferred and non-preferred hands.

Soundwalks: An experiential path to new sonic art

2019 ◽  
Vol 24 (3) ◽  
pp. 261-273
Author(s):  
Christos Carras
Keyword(s):  
Physical Space ◽  
Sonic Art ◽  
The Subject ◽  
Radical Engagement

The diverse practice of soundwalking is approached through its constituent parts (walking and listening) as an ideal ‘way in’ to the appreciation of new sonic art. It is argued that, because it engages the subject in a manner that encourages an aural perception of the environment not only as a physical space but also as a space of social and political tensions, divisions and flows, it can act as an experiential foundation for understanding how sound inflects our thoughts about and our relationships to agencies, human or not, that we interact with. This in turn renders possible modes of listening that are particularly adapted to contemporary forms of sonic art. Furthermore, soundwalking ties in to important contemporary discussions about participation, its potential for radical engagement of audiences and also the various forms of mediation it involves.

scholarly journals Separate motor memories are formed when controlling different implicitly specified locations on a tool

2019 ◽  
Vol 121 (4) ◽  
pp. 1342-1351 ◽  
Author(s):  
Keaton Proud ◽  
James B. Heald ◽  
James N. Ingram ◽  
Jason P. Gallivan ◽  
Daniel M. Wolpert ◽  
...  
Keyword(s):  
Horizontal Plane ◽  
Applied Force ◽  
Control Points ◽  
Contextual Cues ◽  
Task Context ◽  
Object A ◽  
Task Goal ◽  
Straight Line ◽  
Left And Right ◽  
Straight Ahead

Skillful manipulation requires forming and recalling memories of the dynamics of objects linking applied force to motion. It has been assumed that such memories are associated with entire objects. However, we often control different locations on an object, and these locations may be associated with different dynamics. We have previously demonstrated that multiple memories can be formed when participants are explicitly instructed to control different visual points marked on an object. A key question is whether this novel finding generalizes to more natural situations in which control points are implicitly defined by the task. To answer this question, we used objects with no explicit control points and tasks designed to encourage the use of distinct implicit control points. Participants moved a handle, attached to a robotic interface, to control the position of a rectangular object (“eraser”) in the horizontal plane. Participants were required to move the eraser straight ahead to wipe away a column of dots (“dust”), located to either the left or right. We found that participants adapted to opposing dynamics when linked to the left and right dust locations, even though the movements required for these two contexts were the same. Control conditions showed this learning could not be accounted for by contextual cues or the fact that the task goal required moving in a straight line. These results suggest that people naturally control different locations on manipulated objects depending on the task context and that doing so affords the formation of separate motor memories. NEW & NOTEWORTHY Skilled manipulation requires forming motor memories of object dynamics, which have been assumed to be associated with entire objects. However, we recently demonstrated that people can form multiple memories when explicitly instructed to control different visual points on an object. In this article we show that this novel finding generalizes to more natural situations in which control points are implicitly defined by the task.

Application of Satellite Based Augmentation Systems to Altitude Separation

1999 ◽  
Vol 52 (3) ◽  
pp. 313-317
Author(s):  
Jean Pierre Magny
Keyword(s):  
Design Principles ◽  
Preliminary Design ◽  
Vertical Separation ◽  
Safety Issues ◽  
The Subject ◽  
Future Work

This paper presents the application of GNSS1, or more precisely of Satellite Based Augmentation Systems (SBAS), to vertical separation for en-route, approach and landing operations. Potential improvements in terms of operational benefit and of safety are described for two main applications. First, vertical separation between en-route aircraft, which requires a system available across wide areas. SBAS (EGNOS, WAAS, and MSAS) are very well suited for this purpose before GNSS2 becomes available. And secondly, vertical separation from the ground during approach and landing, for which preliminary design principles of instrument approach procedures and safety issues are presented. Approach and landing phases are the subject of discussions within ICAO GNSS-P. En-route phases have been listed as GNSS-P future work and by RTCA for development of new equipments.

scholarly journals Complete slices and homological properties of tilted algebras

1994 ◽  
Vol 36 (3) ◽  
pp. 347-354 ◽  
Author(s):  
Ibrahim Assem ◽  
Flávio Ulhoa Coelho
Keyword(s):  
Representation Theory ◽  
Global Dimension ◽  
Indecomposable Modules ◽  
Tilted Algebra ◽  
Finite Dimensional ◽  
Tilted Algebras ◽  
Homological Dimensions ◽  
The Subject ◽  
Left And Right ◽  
Almost All

It is reasonable to expect that the representation theory of an algebra (finite dimensional over a field, basic and connected) can be used to study its homological properties. In particular, much is known about the structure of the Auslander-Reiten quiver of an algebra, which records most of the information we have on its module category. We ask whether one can predict the homological dimensions of a module from its position in the Auslander-Reiten quiver. We are particularly interested in the case where the algebra is a tilted algebra. This class of algebras of global dimension two, introduced by Happel and Ringel in [7], has since then been the subject of many investigations, and its representation theory is well understood by now (see, for instance, [1], [7], [8], [9], [11], [13]).In this case, the most striking feature of the Auslander-Reiten quiver is the existence of complete slices, which reproduce the quiver of the hereditary algebra from which the tilted algebra arises. It follows from well-known results that any indecomposable successor (or predecessor) of a complete slice has injective (or projective, respectively) dimension at most one, from which one deduces that a tilted algebra is representation-finite if and only if both the projective and the injective dimensions of almost all (that is, all but at most finitely many non-isomorphic) indecomposable modules equal two (see (3.1) and (3.2)). On the other hand, the authors have shown in [2, (3.4)] that a representation-infinite algebra is concealed if and only if both the projective and the injective dimensions of almost all indecomposable modules equal one (see also [14]). This leads us to consider, for tilted algebras which are not concealed, the case when the projective (or injective) dimension of almost all indecomposable successors (or predecessors, respectively) of a complete slice equal two. In order to answer this question, we define the notions of left and right type of a tilted algebra, then those of reduced left and right types (see (2.2) and (3.4) for the definitions).

On the valuation of the mechanical effect of gradients on a line of railroad

1837 ◽  
Vol 3 ◽  
pp. 390-391
Keyword(s):  
Horizontal Plane ◽  
Mechanical Effect ◽  
Small Time ◽  
The Body ◽  
Mechanical Power ◽  
Inclined Plane ◽  
Locomotive Engine ◽  
The Subject ◽  
Source Of Error ◽  
Exact Amount

The exact amount of the influence of ascents and descents occurring in the line of a railway on the motion of a load drawn by a locomotive engine having been differently estimated by different persons, the author was induced to investigate the subject. A few observations are premised on the erroneous assumptions which, he conceives, have in general vitiated the results hitherto deduced. The first of these is that the expenditure of power requisite for motion is equal to the resistance to traction ; whereas it must always greatly exceed it. No account, he remarks, has been taken of the pressure of the atmosphere on the piston, which the force of the steam has to overcome before it can be available as a moving power. Another source of error has been that the statical and dynamical effects of friction have been confounded together ; whereas they are the same in amount only when the body is put in motion by gravity ; but not when it is urged down an inclined plane by an extraneous force. In the latter case these effects are no longer comparable ; friction being a force which, in an infinitely small time, is proportional to the velocity, while that of gravity is constant at all velocities ; or, in other words, the retardation from friction is proportional to the space described, while that from gravity has reference only to the time of acting, whatever space the body may pass over in that time. It is an error to assume that the mechanical power of the plane is equivalent to a reduction of so much friction ; for the friction down the inclined plane is the same as on a horizontal plane of the same length, rejecting the trifling difference of pressure ; and the whole retardation in passing over the plane, or the whole force required to overcome it, is the same at all velocities, and by whatever force the motion is produced ; but the assisting force from gravity is quite independent of the space or of the velocity. In the investigations which the author has prosecuted in this paper, he assumes that equal quantities of steam are produced in the same time at all velocities ; and he adopts for his other data, those given by Mr. Pambour in his Treatise of Locomotive Engines. He deduces a formula from which, the speed on a level being given, we may compute the relative and absolute times of a train ascending a plane ; and consequently also the ratio of the forces expended in the two cases ; or the length of an equivalent horizontal plane ; that is, of one which will require the same time and power to be passed over by the locomotive engine as the ascending plane.

An atlas of the thoracic ganglia in the stick insect, Carausius morosus

1991 ◽  
Vol 331 (1260) ◽  
pp. 101-121 ◽  
Keyword(s):  
Single Unit ◽  
Present Report ◽  
Stick Insect ◽  
Functional Specialization ◽  
Carausius Morosus ◽  
Thoracic Ganglia ◽  
The Third ◽  
Metathoracic Ganglion ◽  
The Subject ◽  
Left And Right

The present report describes the neuroanatomy of the three thoracic ganglia in the stick insect, Carausius morosus , the subject of numerous behavioural and neurobiological studies. The structure of the ganglia is summarized in an atlas of the major features. The results are compared with published descriptions of other insects and arthropods. Numerous similarities with locusts encourage the use of a common nomenclature even where minor differences make homology uncertain pending detailed investigation. Five out of the nine longitudinal tracts described in locusts can be readily identified in the stick insect. Three major tracts (LDT, DIT, VIT) and two smaller tracts (MDT, DMT) are compact and well defined. The VMT and MVT are also prominent but these two tracts are not clearly separated except near the rostral margin of the neuropile. An eighth tract, the VLT, is much less distinct: it is represented by scattered fibres in neuropile lateral to the DIT. The iLVT apd oLVT, the two parts of the ninth tract, are quite inconspicuous: in some, but not all, preparations they can be identified as two thin bands running along the ventral and ventrolateral margins of the ganglion. As in locusts, six dorsal commissures (DCI-DCVI) and five ventral commissures (VCI, vVCII, dVCII, SMC, PVC) connecting the left and right hemiganglia have been named although the two most dorsal commissures, DCII and DCIV, are often subdivided. The VCII is retained as a single unit with dorsal and ventral parts. Of the dorsal-ventral tracts only the transverse tract (TT) and the circle tract (CT) are well-defined. Roots of lateral nerves are left unnamed pending more detailed study but several conspicuous branches are included in the drawings as guides to orientation in the lateral neuropile. The ventral association centre (VAC) and several other neuropile divisions are described. Pro- and mesothoracic ganglia derive from single neuromeres. The metathoracic ganglion results from the fusion of the third thoracic and the first abdominal neuromeres: each part contains its own set of commissures and dorsoventral tracts. The results underline the qualitative similarities of the thoracic ganglia in insects; they provide a basis for more precise descriptions of identified neurons and functional specialization within the ganglia of the stick insect.

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