scholarly journals Mental geometry of 3D size and shape perception

2019 ◽  
Author(s):  
Akihito Maruya ◽  
Qasim Zaidi
Keyword(s):  
Projective Geometry ◽  
Retinal Image ◽  
Relative Size ◽  
Physical Distance ◽  
Image Size ◽  
3D Objects ◽  
Multiplicative Factor ◽  
The World ◽  
Size Invariance ◽  
Mechanical Objects

AbstractJudging poses, sizes and shapes of objects accurately is necessary for organisms and machines to operate successfully in the world. Retinal images of 3D objects are mapped by the rules of projective geometry, and preserve the invariants of that geometry. Since Plato, it has been debated whether geometry is innate to the human brain, and Poincare and Einstein thought it worth examining whether formal geometry arises from experience with the world. We examine if humans have learned to exploit projective geometry to estimate sizes and shapes of objects in 3D scenes.Numerous studies have examined size invariance as a function of physical distance, which changes scale on the retina, but surprisingly, possible constancy or inconstancy of relative size seems not to have been investigated for object pose, which changes retinal image size differently along different axes. We show systematic underestimation of length for extents pointing towards or away from the observer, both for static objects and dynamically rotating objects. Observers do correct for projected shortening according to the optimal back-transform, obtained by inverting the projection function, but the correction is inadequate by a multiplicative factor. The clue is provided by the greater underestimation for longer objects, and the observation that they appear more slanted towards the observer. Adding a multiplicative factor for perceived slant in the back-transform model provides good fits to the corrections used by observers. We quantify the slant illusion with relative slant measurements, and use a dynamic demonstration to show the power of the slant illusion.In biological and mechanical objects, distortions of shape are manifold, and changes in aspect ratio and relative limb sizes are functionally important. Our model shows that observers try to retain invariance of these aspects of shape to 3D rotation by correcting retinal image distortions due to perspective projection, but the corrections can fall short. We discuss how these results imply that humans have internalized particular aspects of projective geometry through evolution or learning, and how assuming that images are preserving the continuity, collinearity, and convergence invariances of projective geometry, supplements the Generic Viewpoint assumption, and simply explains other illusions, such as Ames’ Chair.

scholarly journals “COVID 19- Two Waves & More” What Have We Learnt?

2021 ◽  
Vol 5 (12) ◽  
Author(s):  
Manuj Kumar Sarkar ◽  
Subhra Dey ◽  
Boudhayan Das Munshi
Keyword(s):  
World Health Organisation ◽  
Physical Distance ◽  
World Health ◽  
Chain Reaction ◽  
Tissue Paper ◽  
Hand Sanitizer ◽  
First Case ◽  
The World ◽  
Polymerase Chain ◽  
Bat Coronavirus

The first case of SARS-CoV2 admitted on 26th December 2019 in Central Hospital, Wuhan, China. Broncho-alveolar lavage and Polymerase chain reaction of the aspirate showed high abundance of a viral RNA which has 89.1 % nucleotide identity with bat coronavirus previously isolated in China. Soon human to human transmission was observed and the outbreak started spreading. World Health Organisation on 11th March 2020 declared it as pandemic. COVID 19, caused by SARS-CoV-2, a disease we are still struggling to contain. With vaccination drive throughout the world, though the severity in re-infection has come down, but there is still threat by the various variants which are arising from time to time in various countries. The most effective way of preventing the spread of the virus is to keep physical distance from others of at least 1 meter, wearing a well fitted mask, keep hands clean and use hand sanitizer frequently, stay in well ventilated place, avoid crowded place and cough into bent elbow or tissue paper and get vaccinated when once’s turn comes. Therefore, we urge people to follow COVID appropriate behaviour properly. Keywords: COVID 19, SARS-CoV2, COVID appropriate behaviour, Social Distancing

Offshore Outsourcing

2011 ◽  
pp. 265-282
Author(s):  
Purva Kansal ◽  
Amit Kumar Kaushik
Keyword(s):  
Physical Distance ◽  
Offshore Outsourcing ◽  
The Internet ◽  
Foreign Investors ◽  
Relative Term ◽  
Private Investments ◽  
The World ◽  
Recent Developments ◽  
And Control ◽  
Coordination And Control

In an attempt to influence their pace of development, developing countries around the world try and influence the rate of investment (especially foreign private investments) in their economy. These countries attempt to influence investor decisions by matching and changing their portfolio with that of foreign investors’ needs. However, to make the country portfolio impressive, a country requires massive investment in infrastructure and other portfolio variables which brings countries at an impasse. This chapter discusses the viability of increasing income as a way out. This leads to another important issue as to how to increase revenue of a country with its limited portfolio of strengths. Recent developments in information technology and the Internet have led to a simple solution to this - offshore outsourcing. Outsourcing as a strategy has been around for many years. Traditionally, companies used to outsource their activities to independent suppliers who were best, but the choice was made from the suppliers located in the vicinity of the outsourcing company for easier coordination and control of the activities of the partner. However, due to developments in e-commerce, distance has become a relative term. Exchange of information in a fraction of a minute, irrespective of physical distance, has made it possible for companies to widen their horizons and look for independent suppliers in different nations — offshore outsourcing.

Teaching and Learning Abstract Concepts by Means of Social Virtual Worlds

2017 ◽  
Vol 1 (1) ◽  
pp. 29-42 ◽  
Author(s):  
David Griol ◽  
Zoraida Callejas
Keyword(s):  
Virtual Worlds ◽  
Second Life ◽  
Virtual World ◽  
Teaching And Learning ◽  
Learning Resources ◽  
Abstract Concepts ◽  
Educational Activities ◽  
Virtual Spaces ◽  
3D Objects ◽  
The World

Social Virtual Worlds are increasingly being used in education, as their flexibility can be exploited in order to create heterogeneous groups from all over the world who can collaborate synchronously in different virtual spaces. In this paper, the authors describe the potential of virtual worlds as an educative tool to teach and learn abstract concepts by means of programmable 3D objects. They describe the main experiences carried out recently in the application of these technologies in transnational educational activities that combine the Moodle learning resources and programmable 3D objects in the Second Life virtual world.

scholarly journals Model for the growth of the world airline network

2016 ◽  
Vol 27 (12) ◽  
pp. 1650141 ◽  
Author(s):  
T. Verma ◽  
N. A. M. Araújo ◽  
J. Nagler ◽  
J. S. Andrade ◽  
H. J. Herrmann
Keyword(s):  
Correlation Function ◽  
Growth Model ◽  
Physical Distance ◽  
Transport Networks ◽  
Model Network ◽  
The World ◽  
Airline Networks ◽  
Airline Network ◽  
The Difference

We propose a probabilistic growth model for transport networks which employs a balance between popularity of nodes and the physical distance between nodes. By comparing the degree of each node in the model network and the World Airline Network (WAN), we observe that the difference between the two is minimized for [Formula: see text]. Interestingly, this is the value obtained for the node–node correlation function in the WAN. This suggests that our model explains quite well the growth of airline networks.

TOOLS AND BRAINS IN BIRDS

Behaviour ◽  
2002 ◽  
Vol 139 (7) ◽  
pp. 939-973 ◽  
Author(s):  
Denis Boire ◽  
Nektaria Nicolakakis ◽  
Louis Lefebvre
Keyword(s):  
Cognitive Processes ◽  
Tool Use ◽  
Brain Size ◽  
Short Note ◽  
Relative Size ◽  
The Body ◽  
Whole Brain ◽  
Strong Concentration ◽  
The World ◽  
Innovation Rate

AbstractTools are traditionally defined as objects that are used as an extension of the body and held directly in the hand or mouth. By these standards, a vulture breaking an egg by hitting it with a stone uses a tool, but a gull dropping an egg on a rock does not. This distinction between true and borderline (or proto-tool) cases has been criticized for its arbitrariness and anthropocentrism. We show here that relative size of the neostriatum and whole brain distinguish the true and borderline categories in birds using tools to obtain food or water. From two sources, the specialized literature on tools and an innovation data base gathered in the short note sections of 68 journals in 7 areas of the world, we collected 39 true (e.g. use of probes, hammers, sponges, scoops) and 86 borderline (e.g. bait fishing, battering and dropping on anvils, holding with wedges and skewers) cases of tool use in 104 species from 15 parvorders. True tool users have a larger mean residual brain size (regressed against body weight) than do users of borderline tools, confirming the distinction in the literature. In multiple regressions, residual brain size and residual size of the neostriatum (one of the areas in the avian telencephalon thought to be equivalent to the mammalian neocortex) are the best predictors of true tool use reports per taxon. Innovation rate is the best predictor of borderline tool use distribution. Despite the strong concentration of true tool use cases in Corvida and Passerida, independent constrasts suggest that common ancestry is not responsible for the association between tool use and size of the neostriatum and whole brain. Our results demonstrate that birds are more frequent tool users than usually thought and that the complex cognitive processes involved in tool use may have repeatedly co-evolved with large brains in several orders of birds.

Size-Analysis of Retinal Images by Orientation Detectors

1980 ◽  
Vol 51 (3_suppl2) ◽  
pp. 1307-1330
Author(s):  
Willard L. Brigner
Keyword(s):  
Retinal Image ◽  
Size Analysis ◽  
Retinal Images ◽  
Image Size

A model for the determination of retinal-image size is presented. The size-analysis is based upon the range of orientation detectors activated by a stimulus. The model is applied to size aftereffects and is also used to predict changes in perceived size in configurations which may be expected to affect the range of orientation detectors activated. The relevance of the model to illusions of direction and the perceived length of lines forming angles is also discussed.

scholarly journals Potential Competitiveness of Pound in Post-Crisis World

2020 ◽  
Vol 64 (12) ◽  
pp. 44-53
Author(s):  
A. Kuznetsov
Keyword(s):  
Global Financial Crisis ◽  
International Monetary System ◽  
Relative Size ◽  
External Debt ◽  
Foreign Companies ◽  
Monetary System ◽  
International Currencies ◽  
The World ◽  
The Usa ◽  
The Global Financial Crisis

The author discusses the factors and trends that determine the British pound’s competitive position in various segments of the international monetary system. Despite the devaluation effect caused by Brexit, the pound is still the most expensive of the key international currencies. On the one hand, this is due to the fact that the ratio of the British pound monetary aggregate M1 to GDP is significantly lower than that of other major economies – issuers of reserve currencies. Thus, the pound has the lowest monetary risk of depreciation compared to other currencies. On the other hand, the international significance of the pound sterling is explained by the ability of British economy to service the huge external debt, which in relative size is the largest among the leading economies of the world. This state of affairs is achieved due to the fact that London is home to the largest number of foreign companies in the world that carry out operations in various Eurocurrencies, acting simultaneously as the main issuers of external debt obligations. The attractiveness of the pound sterling as the currency for the nomination of international debt instruments is due to the less risky currency profile of the pound sterling, as well as the relatively higher profitability of debt instruments. After the global financial crisis, the share of the pound in the official reserves of other countries and in the implementation of international payments is gradually increasing. The author comes to the conclusion about the possible strengthening of the future role of the pound as a stabilizer of international economic relations against the backdrop of an increase in unpredictable events taking place on both sides of the Atlantic such as fiscal crisis of the euro area, Brexit, the growing political tension in the USA, COVID 19. These events are increasingly threatening leading positions of the US dollar and the euro as the key international currencies.

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