387,735 research outputs found
A Fisher-Rao metric for paracatadioptric images of lines
No full textIn a central paracatadioptric imaging system a perspective camera takes an image of a scene reflected in a paraboloidal mirror. A 360° field of view is obtained, but
the image is severely distorted. In particular, straight lines in the scene project to circles in the image. These distortions make it diffcult to detect projected lines using standard image processing algorithms. The distortions are removed using a Fisher-Rao metric which is defined on the space of projected lines in the paracatadioptric image. The space of projected lines is divided into subsets such that on each subset the Fisher-Rao metric is closely approximated by the Euclidean metric. Each subset is sampled at the vertices of a square grid and values are assigned to the sampled points using an adaptation of the trace transform. The result is a set of digital images to which standard image processing algorithms can be applied.
The effectiveness of this approach to line detection is illustrated using two algorithms, both of which are based on the Sobel edge operator. The task of line detection is reduced to the task of finding isolated peaks in a Sobel image. An experimental comparison is made between these two algorithms and third algorithm taken from the literature and
based on the Hough transform
Application of the Fisher-Rao metric to ellipse detection
No full textThe parameter space for the ellipses in a two dimensional image is a five dimensional manifold, where each point of the manifold corresponds to an ellipse in the image. The parameter space becomes a Riemannian manifold under a Fisher-Rao metric, which is derived from a Gaussian model for the blurring of ellipses in the image. Two points in the parameter space are close together under the Fisher-Rao metric if the corresponding ellipses are close together in the image. The Fisher-Rao metric is accurately approximated by a simpler metric under the assumption that the blurring is small compared with the sizes of the ellipses under consideration. It is shown that the parameter space for the ellipses in the image has a finite volume under the approximation to the Fisher-Rao metric. As a consequence the parameter space can be replaced, for the purpose of ellipse detection, by a finite set of points sampled from it. An efficient algorithm for sampling the parameter space is described. The algorithm uses the fact that the approximating metric is flat, and therefore locally Euclidean, on each three dimensional family of ellipses with a fixed orientation and a fixed eccentricity. Once the sample points have been obtained, ellipses are detected in a given image by checking each sample point in turn to see if the corresponding ellipse is supported by the nearby image pixel values. The resulting algorithm for ellipse detection is implemented. A multiresolution version of the algorithm is also implemented. The experimental results suggest that ellipses can be reliably detected in a given low resolution image and that the number of false detections
can be reduced using the multiresolution algorithm
The Immortal King Rao
No full textThis is a pre-copyedited, author-produced version of an article accepted for publication in American Historical Review following peer review. The version of record Ramnarayan S Rawat, The Immortal King Rao, The American Historical Review, Volume 129, Issue 3, September 2024, Pages 1029–1031, https://doi.org/10.1093/ahr/rhae236 is available online at: https://doi.org/10.1093/ahr/rhae236.
© The Author(s) 2024. Published by Oxford University Press on behalf of the American Historical Association. All rights reserved. For permissions, please email: [email protected].
This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/pages/standard-publication-reuse-rights).
This article will be embargoed until 09/06/2026.Vauhini Vara. The Immortal King Rao. New York: W. W. Norton & Company, 2022.
“We should be free to pursue our ambitions” (Chinna Rao, owner, coconut grove)
“My ambition is to program” (King Rao)
The Immortal King Rao is an innovative piece of writing that captures the social life of caste and provides a rich ethnography of Dalit ambition, initiative, and achievement through hard work. Several reviewers have written of the novel’s dystopian themes, the existence of a single shareholder’s government managed by an algorithm that has replaced nation-states, and the “exes” or large groups of people who have rejected this system and live in autonomous island zones. Vauhini Vara uses this original framework to offer new insights into Dalit lives by showcasing Dalit ambition and achievement, simultaneously tracing Dalit lives and mobility in India and in the United States while also expanding the genre of caste fiction. As a Dalit woman whose father grew up on a coconut farm in India, Vara has written a formidable novel on breaking free from the shackles of caste through education and migration—in India and abroad
Cramer–Rao lower bounds for change points in additive and multiplicative noise
Get PDFThe paper addresses the problem of determining the Cramer–Rao lower bounds (CRLBs) for noise and change-point parameters, for steplike signals corrupted by multiplicative and/or additive white noise. Closed-form expressions for the signal and noise CRLBs are first derived for an ideal step with a known change point. For an unknown change-point, the noise-free signal is modeled by a sigmoidal function parametrized by location and step rise parameters. The noise and step change CRLBs corresponding to this model are shown to be well approximated by the more tractable expressions derived for a known change-point. The paper also shows that the step location parameter is asymptotically decoupled from the other parameters, which allows us to derive simple CRLBs for the step location. These bounds are then compared with the corresponding mean square errors of the maximum likelihood estimators in the pure multiplicative case. The comparison illustrates convergence and efficiency of the ML estimator. An extension to colored multiplicative noise is also discussed
Wiley CIAexcel Exam Review 2014 Part 3, Internal Audit Knowledge Elements
No full textThe definitive Certified Internal Auditor Exam preparation guide Designed to help you rigorously and thoroughly prepare for the Certified Internal Auditor (CIA) Exam, Wiley CIA Exam Review 2014 Part 3, Internal Audit Knowledge Elements covers the key topics on Part III of the exam. These include business processes; financial accounting and finance; managerial accounting; regulatory, legal, and economics; and information technology. Features a full exploration of theory and concepts Prepares students to properly understand the weight given to topics on the exam and react accordingly Includes indications of the level of difficulty for each topic in order to properly manage study time and focus areas Offers comprehensive coverage of exam material along with a glossary of applicable terminology Expert author S. Rao Vallabhaneni puts his twenty-five years of internal auditing and accounting management experience to work to bring you the definitive resource to help you prepare for the CIA Exa
Cramer-Rao type integral inequalities for general loss functions
No full textBayes risk, Cramer-Rao type integral inequality, Hajek-LeCam lower bound, locally asymptotic minimax error, lower bound, 62G05,
ON THE EQUIVALENCE OF WEIGHTED COUNTRY-PRODUCT-DUMMY (CPD) METHOD AND THE RAO-SYSTEM FOR MULTILATERAL PRICE COMPARISONS
No full textThe country-product-dummy (CPD) method, originally proposed in Summers (1973), has recently been revisited in its weighted formulation to handle a variety of data related situations (Rao and Timmer, 2000, 2003; Heravi et al. , 2001; Rao, 2001; Aten and Menezes, 2002; Heston and Aten, 2002; Deaton et al. , 2004). The CPD method is also increasingly being used in the context of hedonic modelling instead of its original purpose of filling holes in Summers (1973). However, the CPD method is seen, among practitioners, as a black box due to its regression formulation. The main objective of the paper is to establish equivalence of purchasing power parities and international prices derived from the application of the weighted-CPD method with those arising out of the Rao-system for multilateral comparisons. A major implication of this result is that the weighted-CPD method would then be a natural method of aggregation at all levels of aggregation within the context of international comparisons. Copyright 2005 Blackwell Publishing Ltd.
The quest for nonlinearity in time series
No full textIn this chapter, we review the problem of testing for nonlinearity in time series. First, we discuss the definition and the properties of linear processes and the implications that such properties have on the operational strand. Then, we present and review a tentative classification of the various tests that can be found both in the
time series and in the nonlinear dynamics literature. Two main factors contributed to the production of a plethora of alternatives for assessing nonlinearity in time series: the first factor is the intrinsic asymmetry between the linear and the nonlinear
realm. In fact, there can be departures from linearity in various directions as nonlinear phenomena possess a virtually infinite richness of features. Among such features we can mention irreversibility, nonuniform predictability, noise amplification/
suppression, phase synchronization, noise-induced phenomena, sensitivity to initial conditions, and so on. The second factor is the multidisciplinary nature of the problem. Indeed, the problem of characterizing the various aspects of nonlinear processes is shared among different disciplines, such as Statistics, Econometrics,
Nonlinear Dynamics, Biology, and Engineering. The review is by no means exhaustive and reflects the personal inclinations of the autho
S. Rao Aiyagari: my student and my teacher
Get PDFThis essay briefly reviews the professional life and work of economist S. Rao Aiyagari, who died after a heart attack on May 20, 1997, at the age of 45. Aiyagari is described as “one of the ablest economists of his generation.” The essay is accompanied by a complete list of Aiyagari’s published work and reprints of three of his articles in the Federal Reserve Bank of Minneapolis Quarterly Review: “Deflating the Case for Zero Inflation” (Summer 1990), “On the Contribution of Technology Shocks to Business Cycles” (Winter 1994), and “Macroeconomics With Frictions” (Summer 1994).Economists
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