Deformations of canonical double covers

In this paper we show that if X is a smooth variety of general type of dimension m≥2 for which its canonical map induces a double cover onto Y, where Y is the projective space, a smooth quadric hypersurface or a smooth projective bundle over P1, embedded by a complete linear series, then the general deformation of the canonical morphism of X is again canonical and induces a double cover. The second part of the article proves the non-existence of canonical double structures on the rational varieties above mentioned. Our results have consequences for the moduli of varieties of general type of arbitrary dimension, since they show that infinitely many moduli spaces of higher dimensional varieties of general type have an entire “hyperelliptic” component. This is in sharp contrast with the case of curves or surfaces of lower Kodaira dimension.

A Mapping-Scheduling Algorithm for Hardware Acceleration on Reconfigurable Platforms

Reconfigurable platforms are a promising technology that offers an interesting trade-off between flexibility and performance, which many recent embedded system applications demand, especially in fields such as multimedia processing. These applications typically involve multiple ad-hoc tasks for hardware acceleration, which are usually represented using formalisms such as Data Flow Diagrams (DFDs), Data Flow Graphs (DFGs), Control and Data Flow Graphs (CDFGs) or Petri Nets. However, none of these models is able to capture at the same time the pipeline behavior between tasks (that therefore can coexist in order to minimize the application execution time), their communication patterns, and their data dependencies. This paper proves that the knowledge of all this information can be effectively exploited to reduce the resource requirements and the timing performance of modern reconfigurable systems, where a set of hardware accelerators is used to support the computation. For this purpose, this paper proposes a novel task representation model, named Temporal Constrained Data Flow Diagram (TCDFD), which includes all this information. This paper also presents a mapping-scheduling algorithm that is able to take advantage of the new TCDFD model. It aims at minimizing the dynamic reconfiguration overhead while meeting the communication requirements among the tasks. Experimental results show that the presented approach achieves up to 75% of resources saving and up to 89% of reconfiguration overhead reduction with respect to other state-of-the-art techniques for reconfigurable platforms.

El discurso político en el contexto multicultural de las instituciones de la Unión Europea. El discurso político en español y en polaco

The comparative analysis of Polish and Spanish political discourse in the multilingual context of European institutions is challenging not only due to linguistic, cultural, geopolitical and social differences, but also because of a relatively short history of such contacts in the EU framework. Intercultural communication, as a dynamic social practice is a fascinating object of investigation. Bidirectional comparative analysis of Polish and Spanish oral texts allows define the barriers of such communication. It encompasses the discursive act together with its objectives, strategies and consequences, and also its raison d’être. It explains why different strategies reflected through discursive categories were used. Consequently it describes both, conditions and outcomes of identity negotiation. The latter is a political competence perceived and evaluated by the direct interlocutors, the participants of the political debate, and indirectly, by a public opinion of the European Union. That proves it is two-level communication. The negotiation of political identity through discourse, according to the Ting-Toomey theory, can lead to maintaining, loosing, recovering or reinforcing it282. The Identity Negotiation Theory includes the construction and development of personal, relational, role and desired identity and is one of the methodological axes of this investigation. Political identity consists of exhibiting necessary competences to efficiently participate in the legislation process, for example, in order to present amendments, promote a given ideology, participate in controversial discussions and manage conflicts, and, finally, gain the support of public opinion. The analysis of creation, negotiation, maintenance, recovery and promotion of the political identity is performed through the identification and description of discursive categories proposed by Van Dijk283 and adapted to the needs of this study. This is the second methodological axe of the investigation. The following questions arise: which discursive strategies, used by Polish and Spanish politicians, will be communication facilitators and which will be barriers hampering communication? Which strategies show political competencies of the speaker, his or her influence in the legal EU reality through discourse?...