857 research outputs found

    Economics for the Masses : The Visual Display of Economic Knoledge in the United Staes (1921-1945)

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    The rise of visual representation in economics textbooks after WWII is one of the main features of contemporary economics. In this paper, we argue that this development has been preceded by a no less significant rise of visual representation in the larger literature devoted to social and scientific issues, including economic textbooks for non-economists as well as newspapers and magazines. During the interwar era, editors, propagandists and social scientists altogether encouraged the use of visual language as the main vehicle to spread information and opinions about the economy to a larger audience. These new ways of visualizing social facts, which most notably helped shape the understanding of economic issues by various audiences during the years of the Great Depression, were also conceived by their inventors as alternative ways of practicing economics: in opposition to the abstraction of “neoclassical” economics, these authors wanted to use visual representation as a way to emphasize the human character of the discipline and did not accept the strict distinction between the creation and the diffusion of economic knowledge. We explore different yet related aspects of these developments by studying the use of visual language in economics textbooks intended for non-specialists, in periodicals such as the Survey, a monthly magazine intended for an audience of social workers, the Americanization of Otto Neurath's pictorial statistics and finally the use of those visual representations by various state departments and administrations under Roosevelt's legislature (including the much-commented Historical Section of the Farm Security Administration). We show how visualizations that have been created in opposition to neoclassical economics have lost most of their theoretical content when used widely for policy purposes while being simultaneously integrated into the larger American culture. It is our claim that those issues, which are familiar to those involved in cultural and visual studies, are also of crucial importance to apprehend the later developments of modern economics.Visualization, economocs, American Economy, Otto Neurath, Rexford Tugwell, Roosevelt, Roy Stryker, Photographs, Pictorial Statistics

    Material independent crack arrest statistics

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    The propagation of (planar) cracks in a heterogeneous brittle material characterized by a random field of toughness is considered, taking into account explicitly the effect of the crack front roughness on the local stress intensity factor. In the so-called strong-pinning regime, the onset of crack propagation appears to map onto a second-order phase transition characterized by universal critical exponents which are independent of the local characteristics of the medium. Propagation over large distances can be described by using a simple one-dimensional description, with a correlation length and an effective macroscopic toughness distribution that scale in a non-trivial fashion with the crack front length. As an application of the above concepts, the arrest of indentation cracks is addressed, and the analytical expression for the statistical distribution of the crack radius at arrest is derived. The analysis of indentation crack radii on alumina is shown to obey the predicted algebraic expression for the radius distribution and its dependence on the indentation load

    Positioning System for a Hand-Held Mine Detector

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    Humanitarian mine clearance aims at reducing the nuisance of regions infected by explosive devices. These devices need to be detected with a high rate of success while keeping a low false alarm rate to reduce time losses and personnel’s fatigue. This chapter describes a positioning system developed to track hand-held detector movements in the context of close-range mine detection. With such a system, the signals captured by the detector over time can be used to build two- or three-dimensional data. The objects possibly present in the data can then be visually appreciated by an operator to detect specific features such as shape or size or known signatures. The positioning system developed in the framework of the HOPE European project requires only a camera and an extra bar. It adds few constraints to current mine clearance procedures and requires limited additional hardware. The software developed for calibration and continuous acquisition of the position is described, and evaluation results are presented

    A geometric dissimilarity criterion between Jordan spatial mosaics. Theoretical aspects and application to segmentation evaluation

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    International audienceAn image segmentation process often results in a special spatial set, called a mosaic, as the subdivision of a domain S within the n-dimensional Euclidean space. In this paper, S will be a compact domain and the study will be focused on finite Jordan mosaics, that is to say mosaics with a finite number of regions and where the boundary of each region is a Jordan hypersurface. The first part of this paper addresses the problem of comparing a Jordan mosaic to a given reference Jordan mosaic and introduces the (Epsilon) dissimilarity criterion. The second part will show that the (Epsilon) dissimilarity criterion can be used to perform the evaluation of image segmentation processes. It will be compared to classical criterions in regard to several geometric transformations. The pros and cons of these criterions are presented and discussed, showing that the dissimilarity criterion outperforms the other ones

    Deux ethnologues dans le métro

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    International audience« Nous sommes embarqués ». En partant de cette spécificité du « terrain » pour qui étudie les pratiques du métro, les auteurs reviennent sur la double enquête qu’ils ont menée sur celui du Caire. Mis en place à partir de la fin des années 1980, il est souvent présenté comme une oasis miraculeuse d’ordre et de propreté. J.-C. Depaule et P. Tastevin se sont interrogés sur la façon de rendre compte de ce « lieu mouvement » : de prendre la mesure d’une histoire en train de se faire ; d’observer les manifestations d’un savoir-vivre commun qui, selon eux, doit être rapproché des convenances observables dans l’espace de l’habitation (et ne saurait donc être imputé au seuls dispositifs « disciplinaires » conçus par les promoteurs et gestionnaires). Ils proposent en outre quelques réflexions sur les vertus et les limites d’une approche et d’une écriture à deux

    Characterization of the corneal endothelial mosaic and comparison with simulated tessellations modeled withGaussian random fields

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    International audienceIn this article, manually segmented corneal endothelial mosaic will be characterized with spatial statistical functionsand criteria issued from granulometry and morphometry. A novel approach to simulate spatial tessellationswith Gaussian random fields with Gaussian and Bessel covariance functions, watershed and h-maxima is reported.Finally, these random spatial tessellations will be characterized and compared to corneal mosaics

    A feature-based dense local registration of pairs of retinal images.

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    International audienceA method for spatial registering pairs of digital images of the retina is presented, using intrinsic feature points (landmarks) and dense local transformation. First, landmarks, i.e. blood vessel bifurcations, are extracted from both retinal images using filtering followed by thinning and branch point analysis. Correspondances are found by topological and structural comparisons between both retinal networks. From this set of matching points, a displacement field is computed and, finally, one of the two images is transformed. Due to complex retinal registration problem, the presented transformation is dense, local and adaptive. Experimental results established the effectiveness and the interest of the dense registration method

    Automatic quantitative evaluation of image registration techniques with the "epsilon" dissimilarity criterion in the case of retinal images.

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    International audienceIn human retina observation (with non mydriatic optical microscopes), a registration process is often employed to enlarge the field of view. For the ophthalmologist, this is a way to spare time browsing all the images. A lot of techniques have been proposed to perform this registration process, and indeed, its good evaluation is a question that can be raised. This article presents the use of the "epsilon" dissimilarity criterion to evaluate and compare some classical featurebased image registration techniques. The problem of retina images registration is employed as an example, but it could also be used in other applications. The images are first segmented and these segmentations are registered. The good quality of this registration is evaluated with the "epsilon" dissimilarity criterion for 25 pairs of images with a manual selection of control points. This study can be useful in order to choose the type of registration method and to evaluate the results of a new one

    Quantitative evaluation of image registration techniques in the case of retinal images

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    International audienceIn human retina observation (with non mydriatic optical microscopes), an image registration process is often employed to enlarge the field of view. Analyzing all the images takes a lot of time. Numerous techniques have been proposed to perform the registration process. Its good evaluation is a difficult question that is then raising. This article presents the use of two quantitative criterions to evaluate and compare some classical feature-based image registration techniques. The images are first segmented and the resulting binary images are then registered. The good quality of the registration process is evaluated with a normalized criterion based on the ϵ dissimilarity criterion, and the figure of merit criterion (fom), for 25 pairs of images with a manual selection of control points. These criterions are normalized by the results of the affine method (considered as the most simple method). Then, for each pair, the influence of the number of points used to perform the registration is evaluated
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