6 resultados para Contemporary capitalist system of production
em Université de Montréal, Canada
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The aim of this paper is to demonstrate that, even if Marx's solution to the transformation problem can be modified, his basic concusions remain valid.
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We survey recent axiomatic results in the theory of cost-sharing. In this litterature, a method computes the individual cost shares assigned to the users of a facility for any profile of demands and any monotonic cost function. We discuss two theories taking radically different views of the asymmetries of the cost function. In the full responsibility theory, each agent is accountable for the part of the costs that can be unambiguously separated and attributed to her own demand. In the partial responsibility theory, the asymmetries of the cost function have no bearing on individual cost shares, only the differences in demand levels matter. We describe several invariance and monotonicity properties that reflect both normative and strategic concerns. We uncover a number of logical trade-offs between our axioms, and derive axiomatic characterizations of a handful of intuitive methods: in the full responsibility approach, the Shapley-Shubik, Aumann-Shapley, and subsidyfree serial methods, and in the partial responsibility approach, the cross-subsidizing serial method and the family of quasi-proportional methods.
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Rapport de recherche
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Static oligopoly analysis predicts that if a single firm in Cournot equilibrium were to be constrained to contract its production marginally, its profits would fall. on the other hand, if all the firms were simultaneously constrained to reduce their productino, thus moving the industry towards monopoly output, each firm's profit would rise. We show that these very intuitive results may not hold in a dynamic oligopoly.
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Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.
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Objective To determine scoliosis curve types using non invasive surface acquisition, without prior knowledge from X-ray data. Methods Classification of scoliosis deformities according to curve type is used in the clinical management of scoliotic patients. In this work, we propose a robust system that can determine the scoliosis curve type from non invasive acquisition of the 3D back surface of the patients. The 3D image of the surface of the trunk is divided into patches and local geometric descriptors characterizing the back surface are computed from each patch and constitute the features. We reduce the dimensionality by using principal component analysis and retain 53 components using an overlap criterion combined with the total variance in the observed variables. In this work, a multi-class classifier is built with least-squares support vector machines (LS-SVM). The original LS-SVM formulation was modified by weighting the positive and negative samples differently and a new kernel was designed in order to achieve a robust classifier. The proposed system is validated using data from 165 patients with different scoliosis curve types. The results of our non invasive classification were compared with those obtained by an expert using X-ray images. Results The average rate of successful classification was computed using a leave-one-out cross-validation procedure. The overall accuracy of the system was 95%. As for the correct classification rates per class, we obtained 96%, 84% and 97% for the thoracic, double major and lumbar/thoracolumbar curve types, respectively. Conclusion This study shows that it is possible to find a relationship between the internal deformity and the back surface deformity in scoliosis with machine learning methods. The proposed system uses non invasive surface acquisition, which is safe for the patient as it involves no radiation. Also, the design of a specific kernel improved classification performance.