scholarly journals The Role of the Centre of Projection in the Estimation of Slant from Texture of Planar Surfaces

Perception ◽  
10.1068/p3002 ◽  
2001 ◽  
Vol 30 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Stefaan Tibau ◽  
Bert Willems ◽  
Erik Van Den Bergh ◽  
Johan Wagemans
Keyword(s):  
Estimation Error ◽  
Stimulus Display ◽  
Perspective Projection ◽  
Viewing Distance ◽  
Circular Aperture ◽  
Focal Distance ◽  
Square Grid ◽  
Specific Combination ◽  
Planar Surfaces

Displays were presented consisting of a perspective projection of a regular square grid, made up of vertical and horizontal equally spaced white lines, that was slanted in depth. The surface was viewed monocularly, through a circular aperture. A range of slants was shown (0°, 10°, 20°, 30°, 40°, 50°, or 60°) and the observers' task was to match the slant by means of a mouse-driven probe. The viewing distance (50, 75, or 100 cm) as well as the focal distance (25, 50, 75, 100, or 125 cm) were varied. We expected the estimation error to be smallest when the viewing distance and the focal distance coincided. This was not the case. Instead, subjects seemed to use the perspective deformation of the texture elements in the stimulus display to make a slant estimation, regardless of the specific combination of viewing distance and focal distance.

scholarly journals The Quality of Accruals and Earnings: The Role of Accrual Estimation Errors

2002 ◽  
Vol 77 (s-1) ◽  
pp. 35-59 ◽  
Author(s):  
Patricia M. Dechow ◽  
Ilia D. Dichev
Keyword(s):  
Estimation Error ◽  
Cash Flows ◽  
Empirical Measure ◽  
Earnings Persistence ◽  
Working Capital ◽  
Estimation Errors ◽  
Accrual Quality ◽  
Flows Over Time

This paper suggests a new measure of one aspect of the quality of working capital accruals and earnings. One role of accruals is to shift or adjust the recognition of cash flows over time so that the adjusted numbers (earnings) better measure firm performance. However, accruals require assumptions and estimates of future cash flows. We argue that the quality of accruals and earnings is decreasing in the magnitude of estimation error in accruals. We derive an empirical measure of accrual quality as the residuals from firm-specific regressions of changes in working capital on past, present, and future operating cash flows. We document that observable firm characteristics can be used as instruments for accrual quality (e.g., volatility of accruals and volatility of earnings). Finally, we show that our measure of accrual quality is positively related to earnings persistence.

scholarly journals The Role of Buckling in the Estimation of Compressive Strength of Corrugated Cardboard Boxes

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4578 ◽  
Author(s):  
Tomasz Garbowski ◽  
Tomasz Gajewski ◽  
Jakub Krzysztof Grabski
Keyword(s):  
Compressive Strength ◽  
Analytical Approach ◽  
Estimation Error ◽  
Full Range ◽  
Shear Stiffness ◽  
Width Ratio ◽  
Force Estimation ◽  
Corrugated Cardboard ◽  
Precise Prediction

This paper presents analytical methods for estimating the static top-to-bottom compressive strength of simple corrugated packaging, in which the torsional and shear stiffness of corrugated cardboard as well as the panel depth-to-width ratio are included. The methods are compared herein with a basic and more detailed buckling description with the successful McKee formula, which is over fifty years old but still widely used among packaging designers and quality control departments. Additionally, the assumptions and applied simplifications used in the literature are analyzed, and the limits of applicability of different versions of the selected methods are checked. Finally, all approaches are verified with the experiment results of various packaging designs made of corrugated cardboard. The results show that, for certain proportions of dimensions of simple flap boxes, simplified methods give an even two times larger estimation error than the analytical approach proposed in the paper. Furthermore, it is evidenced that including all flexural, torsional and shear stiffnesses in the buckling force estimation gives a very precise prediction of the box compressive strength for the full range of package dimensions.

A method for stereo-vision-based tracking for robotic applications

Robotica ◽  
2009 ◽  
Vol 28 (4) ◽  
pp. 517-524 ◽  
Author(s):  
Pubudu N. Pathirana ◽  
Adrian N. Bishop ◽  
Andrey V. Savkin ◽  
Samitha W. Ekanayake ◽  
Timothy J. Black
Keyword(s):  
Computer Simulation ◽  
Stereo Vision ◽  
Vision System ◽  
Estimation Error ◽  
Linear Measurement ◽  
Linear Filter ◽  
Perspective Projection ◽  
Non Linear ◽  
Measurement Equations ◽  
Robotic Applications

SUMMARYVision-based tracking of an object using perspective projection inherently results in non-linear measurement equations in the Cartesian coordinates. The underlying object kinematics can be modelled by a linear system. In this paper we introduce a measurement conversion technique that analytically transforms the non-linear measurement equations obtained from a stereo-vision system into a system of linear measurement equations. We then design a robust linear filter around the converted measurement system. The state estimation error of the proposed filter is bounded and we provide a rigorous theoretical analysis of this result. The performance of the robust filter developed in this paper is demonstrated via computer simulation and via practical experimentation using a robotic manipulator as a target. The proposed filter is shown to outperform the extended Kalman filter (EKF).

scholarly journals Relational Space and Life Geographies in Imperial History: George Arthur and Humanitarian Governance

2011 ◽  
Vol 21 (2) ◽  
pp. 29-46
Author(s):  
Alan Lester
Keyword(s):  
Space And Place ◽  
Imperial History ◽  
Specific Combination ◽  
New Approaches ◽  
The Family ◽  
Relational Space ◽  
Colonial Governance ◽  
Military Networks ◽  
The Individual

This paper focuses on the personality and agency of George Arthur, situating them within broader discursive assemblages. It begins by examining new approaches to the role of the individual in society that are linked to the relativisation of our ideas of space and place. It then examines three sets of relationships that shaped Arthur and, to varying extents, that he gained the capacity to shape: military networks, discourses of the family and humanitarian governance. Pointing to a specific combination of anti-democratic and humane notions of governance, it argues that Arthur’s acquisition of capacity in this sphere helped effect a transition from anti-slavery to humanitarian colonial governance in and across a variety of colonial spaces.

The role of weak interactions in controlling the mode of interpenetration in hybrid ultramicroporous materials

2017 ◽  
Vol 53 (28) ◽  
pp. 3978-3981 ◽  
Author(s):  
Alankriti Bajpai ◽  
Matteo Lusi ◽  
Michael J. Zaworotko
Keyword(s):  
Weak Interactions ◽  
Square Grid ◽  
Grid Networks

The aromatic core in dipyridyl linker ligands is found to impact the mode of 2-fold interpenetration in hybrid ultramicroporous materials formed by pillared square grid networks.

The Role of Depth Stratification in the Solution of the Aperture Problem

Perception ◽  
1993 ◽  
Vol 22 (2) ◽  
pp. 215-228 ◽  
Author(s):  
Paola Bressan ◽  
Giorgio Ganis ◽  
Giorgio Vallortigara
Keyword(s):  
Vertical Direction ◽  
Vertical Motion ◽  
Circular Aperture ◽  
Sources Of Information ◽  
Vertical Grating ◽  
Asymmetrical Information ◽  
Aperture Problem ◽  
The Difference ◽  
Depth Stratification

When a plaid pattern composed of a stationary vertical grating and a horizontally drifting diagonal grating is shown behind a circular aperture, the pattern appears to move coherently in a vertical direction. When the bars of the stationary grating are narrower than those of the moving grating, only the latter is seen to move, in a direction orthogonal to its orientation (ie diagonal); but when the bars of the stationary grating are wider than those of the moving grating, vertical motion of the whole plaid predominates. It is argued that, in the absence of occlusion information, the motion of a plaid within an aperture depends on the unambiguous displacement of inner line terminators at the crossings of the two gratings. Relative motion and differences in bar width between the two gratings provide information about which set of bars is in front of the other. When these sources of information are consistent with each other, separation of the two gratings in depth occurs: inner line terminators no longer perceptually exist and the direction of motion becomes determined only by terminators at the edges, which causes a shift from vertical to orthogonal motion. Differences in luminance also provide (asymmetrical) information about depth relationships: when darker bars occlude lighter bars, the probability of orthogonal motion increases as a function of the difference in luminance, whereas when lighter bars are over darker bars, vertical motion prevails.

scholarly journals Effect of Viewing Distance On Object Responses In Macaque Areas 45B, F5a And F5p

2021 ◽  
Author(s):  
Irene Caprara ◽  
Peter Janssen
Keyword(s):  
Visual Representation ◽  
Motor Command ◽  
Peripersonal Space ◽  
Visual Object ◽  
Viewing Distance ◽  
Visually Guided ◽  
Grip Aperture ◽  
Object Processing ◽  
The Brain

Abstract To perform tasks like grasping, the brain has to process visual object information so that the grip aperture can be adjusted before touching the object. Previous studies have demonstrated that the posterior subsector of the Anterior Intraparietal area (pAIP) is connected to area 45B, and its anterior counterpart (aAIP) to F5a. However, the role of area 45B and F5a in visually-guided grasping is poorly understood. Here, we investigated the role of area 45B, F5a and F5p in object processing during visually-guided grasping in two monkeys. If the presentation of an object activates a motor command related to the preshaping of the hand, as in F5p, such neurons should prefer objects presented within reachable distance. Conversely, neurons encoding a purely visual representation of an object – possibly in area 45B and F5a – should be less affected by viewing distance. Contrary to our expectations, we found that most neurons in area 45B were object- and viewing distance-selective (mostly Near-preferring). Area F5a showed much weaker object selectivity compared to 45B, with a similar preference for objects presented at the Near position. Finally, F5p neurons were less object selective and frequently Far-preferring. In sum, area 45B – but not F5p– prefers objects presented in peripersonal space.

scholarly journals Médeia, a korinthosi feleség

2017 ◽  
Vol 56 (1-4) ◽  
Author(s):  
Judit D. Tóth
Keyword(s):  
The Other ◽  
Traditional Role ◽  
Specific Combination ◽  
Other Woman ◽  
The Ideal

Among the modern interpretations of Medea, one of the most influential plays by Euripides, which was first performed in 431 BC, there is a so-called “barbarian Medea” reading, which explains the murderous deeds of the heroine (including the killing of her own children) primarily through her barbarian descent and otherness. In this paper, however, I wish to join another trend among the related, rather expansive, research efforts, which identifies the ultimate reason for the revenge taken by this fierce and impetuous protagonist not in her otherness deriving from her barbarity but essentially in her quality as a cheated and humiliated spouse. In my study, I intend to focus on the figure of Medea as a “Corinthian wife” on the basis of three significant locations in the text of the play: the speech of the Nurse (1–45), Medea’s lamentation (214–267), and the agon between Medea and Jason (446–626). It is my intention to contend that during the “peaceful” years spent in Corinth (cf. 11–15), Medea is an average wife, just like any other woman of her age, until Jason decides to leave her. At this point, however, since she takes Jason’s oath sworn to Zeus and the other gods seriously, she abandons the traditional role of “the ideal wife” and exacts her revenge planned on the prompt of her desperation and the specific combination of circumstances. All this relates her back to her mythic past but, in this case, her barbarity becomes an indication of her otherness as a woman, the same way as her deeds become a medium of the experience shared by contemporary spouses and women.

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