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

Understanding Irregular Migration Through a Social Systems Perspective

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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

research policy dialogues in italy

Italy is usually characterised by political scientists as a country with a high degree of penetration of party politics over public administration and civil society. Experts are often considered either marginal or controversial figures. Especially when involved in policymaking, experts tend to be linked to specific political parties, and claims of impartiality are met with suspicion. This explains why in Italy it took a rather long time before a true dialogue between academia and policymakers developed, while once a formal dialogue structure was set in place, in the late 1990s, it did not last very long. Since then, the use of expert knowledge by policy makers has been primarily of a symbolic nature, either of a legitimising or of a substantiating kind, or it has not been used at all. For instrumental utilisation to occur, responsible and interested policymakers and public officials must be in place, a condition that seems to have been met in only few specific cases

Non-formal spaces of socio-cultural accompaniment: Responding to young unaccompanied refugees – reflections from the Partispace project.

Drawing on research in progress in the Partispace project we make a case for the recognition of the importance of non-formal spaces in response to young refugees across three different national contexts: Frankfurt in Germany; Gothenburg in Sweden; and Manchester in the UK. It is argued that recognition of local regulation and national controls of immigration which support climates of hostility makes it important to recognise and affirm the significance of non-formal spaces and ‘small spaces close to home’ which are often developed in the ‘third space’ of civil society and arise from the impulses driven by the solidarity of volunteers. In these contexts it is important that practices of hospitality can develop which symbolically reconstitute refugees as hosts and subjects of a democratic conversation, without which there is no possible administrative solution to the refugee crisis. It is essential that educational spaces such as schools, colleges and universities forge strong bonds with such emergent spaces