Modulo scheduling for a fully-distributed clustered VLIW architecture

Clustering is an approach that many microprocessors are adopting in recent times in order to mitigate the increasing penalties of wire delays. We propose a novel clustered VLIW architecture which has all its resources partitioned among clusters, including the cache memory. A modulo scheduling scheme for this architecture is also proposed. This algorithm takes into account both register and memory inter-cluster communications so that the final schedule results in a cluster assignment that favors cluster locality in cache references and register accesses. It has been evaluated for both 2- and 4-cluster configurations and for differing numbers and latencies of inter-cluster buses. The proposed algorithm produces schedules with very low communication requirements and outperforms previous cluster-oriented schedulers.Peer ReviewedPostprint (published version

The effectiveness of loop unrolling for modulo scheduling in clustered VLIW architectures

Clustered organizations are becoming a common trend in the design of VLIW architectures. In this work we propose a novel modulo scheduling approach for such architectures. The proposed technique performs the cluster assignment and the instruction scheduling in a single pass, which is shown to be more effective than doing first the assignment and later the scheduling. We also show that loop unrolling significantly enhances the performance of the proposed scheduler especially when the communication channel among clusters is the main performance bottleneck. By selectively unrolling some loops, we can obtain the best performance with the minimum increase in code size. Performance evaluation for the SPECfp95 shows that the clustered architecture achieves about the same IPC (Instructions Per Cycle) as a unified architecture with the same resources. Moreover when the cycle time is taken into account, a 4-cluster configurations is 3.6 times faster than the unified architecture.Peer ReviewedPostprint (published version

Fast, accurate and flexible data locality analysis

This paper presents a tool based on a new approach for analyzing the locality exhibited by data memory references. The tool is very fast because it is based on a static locality analysis enhanced with very simple profiling information, which results in a negligible slowdown. This feature allows the tool to be used for highly time-consuming applications and to include it as a step in a typical iterative analysis-optimization process. The tool can provide a detailed evaluation of the reuse exhibited by a program, quantifying and qualifying the different types of misses either globally or detailed by program sections, data structures, memory instructions, etc. The accuracy of the tool is validated by comparing its results with those provided by a simulator.Peer ReviewedPostprint (published version

Feature selection for microarray gene expression data using simulated annealing guided by the multivariate joint entropy

In this work a new way to calculate the multivariate joint entropy is presented. This measure is the basis for a fast information-theoretic based evaluation of gene relevance in a Microarray Gene Expression data context. Its low complexity is based on the reuse of previous computations to calculate current feature relevance. The mu-TAFS algorithm --named as such to differentiate it from previous TAFS algorithms-- implements a simulated annealing technique specially designed for feature subset selection. The algorithm is applied to the maximization of gene subset relevance in several public-domain microarray data sets. The experimental results show a notoriously high classification performance and low size subsets formed by biologically meaningful genes.Postprint (published version

Ayudando a los pacientes con cáncer

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Los nuevos entornos educativos: desafíos cognitivos para una inteligencia colectiva New Educational Settings. Cognitive Challenges for the Realization of a Collective Intelligence

Comprender las tecnologías de la comunicación a la luz de las redes con que se comunican y entran en cooperación las personas ha sido una constante en autores que no han disociado su visión acerca del significado de las tecnologías respecto a los nuevos movimientos sociales. Este artículo sostiene que las TIC no son sólo una red a la que se suman los individuos, sino que actúan como tecnologías sociales cuyo perfeccionamiento depende tanto de la diversidad de sus funciones (socio-políticas, cognitivas, etc.) como de la flexibilidad con que se adapten a nuestra diversidad funcional (ciclos de la vida, motricidad, umbrales de percepción, etc.). Prueba de ello son desafíos tecnológicos como el diseño de dispositivos llevables, las redes de área personal, las interfaces de usuario de alta usabilidad, los sistemas de cuidado en el hogar, etc. Este artículo explora dichas tesis en relación con el entorno educativo. Understanding communication technologies through the networks by which people connect, communicate and cooperate has been a constant feature in the work of researchers who have not dissociated their view about the meaning of technologies within new social movements. This paper states that Information and Communication Technologies are not only networks that people join individually, but that they also act as social technologies. Their improvement depends both on the diversity of their functions (social, political, cognitive, etc.) and on the flexibility they have to adapt to functional diversity (to lifecycles, changing and fluctuating mobility or to audiovisual perception thresholds, for example). This idea is supported by the new technological challenge represented by portable devices, the personal area network, high-use user interfaces, systems designed for home care, etc. All this will be tried and tested in this paper within the educational context