Geodesics in Heat

We introduce the heat method for computing the shortest geodesic distance to a specified subset (e.g., point or curve) of a given domain. The heat method is robust, efficient, and simple to implement since it is based on solving a pair of standard linear elliptic problems. The method represents a significant breakthrough in the practical computation of distance on a wide variety of geometric domains, since the resulting linear systems can be prefactored once and subsequently solved in near-linear time. In practice, distance can be updated via the heat method an order of magnitude faster than with state-of-the-art methods while maintaining a comparable level of accuracy. We provide numerical evidence that the method converges to the exact geodesic distance in the limit of refinement; we also explore smoothed approximations of distance suitable for applications where more regularity is required

Quad Meshing

Triangle meshes have been nearly ubiquitous in computer graphics, and a large body of data structures and geometry processing algorithms based on them has been developed in the literature. At the same time, quadrilateral meshes, especially semi-regular ones, have advantages for many applications, and significant progress was made in quadrilateral mesh generation and processing during the last several years. In this State of the Art Report, we discuss the advantages and problems of techniques operating on quadrilateral meshes, including surface analysis and mesh quality, simplification, adaptive refinement, alignment with features, parametrization, and remeshing

Ethics, politics and migration: Public debates on the free movement of Romanians and Bulgarians in the UK, 2006–2013

Public debates on immigration have become the subject of much concern, particularly in the UK. This article applies an ethical lens to assess changes in public debates over intra-EU migration in six UK national newspapers during 2006 and 2013. It finds an almost complete dominance of communitarian justifications, mainly based on welfare chauvinism, but a notable increase in security-related arguments and a decrease in economic nationalist ideas. Alternative cosmopolitan arguments about immigration go from rare to virtually absent. The discussion links these shifts to a failure of the UK centre-left to overcome historic difficulties in presenting a coherent narrative on immigration policy

Methodological Note

AbstractThe second part of the book will present the results of an empirical study of the experience of Ecuadorian irregular migrants in the cities of Amsterdam and Madrid. While the general overview of the methodological conceptualization that is the backbone of the whole research work has already been outlined in the introduction, in this brief chapter the focus will be centred on the specific methodological issues concerning the empirical study

Governança e governamentalidade: relação e relevância de dois conceitos científico-sociais proeminentes na educação comparada

Contrapondo-se ao retrospecto da existência de uma relação volátil entre o Estado e "seu" sistema educacional, este trabalho enfoca dois conceitos que podem ser empregados como ferramentas de análise para estudar as transformações em curso. O termo "governança" está mais relacionado a aspectos técnicos: tratam-se de instrumentos e modos, procedimentos e atores, além de suas constelações e formas de cooperação. Ele concentra a pesquisa em questões como: quem oferece serviços educacionais, qual é a relação entre ensino público e privado etc. Ele também é extremamente útil na investigação da relação entre os diversos níveis de análise e provou-se particularmente importante para a compreensão teórica adequada do papel das organizações internacionais na formulação de políticas educacionais. A sociologia e a ciência política são duas disciplinas cuja associação se mostra mais notável na elaboração do conceito sob diversas perspectivas. "Governamentalidade", por sua vez, apesar de compartilhar muitas características com governança, é um termo foucautiano dedicado à geração de subjetividades distintas por meio de técnicas e modos de regulação e conduta em sentido lato. Assim, governamentalidade inclui investigações do nexo tipicamente foucautiano conhecimento/poder. Consideramos ambas as perspectivas em conjunto para discutir suas implicações para a educação comparada.Against the background of a changing relation between the state and "its" education system, the present contribution focuses on two concepts that can be used as analytical tools in order to analyze the current transformations. "Governance" is more concerned with technical issues: with instruments and modes, procedures and actors, with their constellations and forms of cooperation. It focuses research on questions such as: who provides educational services, what is the relation between public and private education etc. It is also very useful in investigating the relation between the various levels of analysis and has proven particularly useful for an adequate theoretical understanding of the role of international organizations in shaping educational policies. Sociology and political science are the two disciplines most prominently associated with elaborating the concept under various perspectives. Governmentality, on the other hand, although sharing many characteristics with governance, is a Foucauldian term concerned with the generation of different subjectivities through techniques and modes of ruling and guiding in an encompassing sense. Governmentality thus includes investigations of the typical Foucauldian knowledge/power nexus. Both perspectives are brought together to discuss the implications for comparative education

Irregular Migration Theories

n/

Differentiation theory and the ontologies of regionalism in Latin America

Abstract In this article, we argue that conventional understandings of regional integration based on neo-functionalism, hitherto often used to describe the diverse projects of Latin American regionalism, are of limited utility in that context. Rather than representing processes of economic or political unification, the various regionalisms could be understood more productively as a reaction to the crisis in legitimacy that social orders in the region have experienced under the conditions of globalized modernity. We then deploy an understanding of regionalism derived from sociological differentiation theory in order to advance this argument

Geodesic Distance Computation via Virtual Source Propagation

We present a highly practical, efficient, and versatile approach for computing approximate geodesic distances. The method is designed to operate on triangle meshes and a set of point sources on the surface. We also show extensions for all kinds of geometric input including inconsistent triangle soups and point clouds, as well as other source types, such as lines. The algorithm is based on the propagation of virtual sources and hence easy to implement. We extensively evaluate our method on about 10 000 meshes taken from the Thingi10k and the Tet Meshing in the Wild data sets. Our approach clearly outperforms previous approximate methods in terms of runtime efficiency and accuracy. Through careful implementation and cache optimization, we achieve runtimes comparable to other elementary mesh operations (e.g. smoothing, curvature estimation) such that geodesic distances become a “first-class citizen” in the toolbox of geometric operations. Our method can be parallelized and we observe up to 6× speed-up on the CPU and 20× on the GPU. We present a number of mesh processing tasks easily implemented on the basis of fast geodesic distances. The source code of our method is provided as a C++ library under the MIT license