103 research outputs found

    CellSim: a validated modular heterogeneous multiprocessor simulator

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    As the number of transistors on a chip continues increasing the power consumption has become the most important constraint in processors design. Therefore, to increase performance, computer architects have decided to use multiprocessors. Moreover, recent studies have shown that heterogeneous chip multiprocessors have greater potential than homogeneous ones. We have built a modular simulator for heterogeneous multiprocessors that can be configure to model IBM's Cell Processor. The simulator has been validated against the real machine to be used as a research tool.Peer ReviewedPostprint (published version

    Manifold learning for coherent design interpolation based on geometrical and topological descriptors

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    In the context of intellectual property in the manufacturing industry, know-how is referred to practical knowledge on how to accomplish a specific task. This know-how is often difficult to be synthesised in a set of rules or steps as it remains in the intuition and expertise of engineers, designers, and other professionals. Today, a new research line in this concern spot-up thanks to the explosion of Artificial Intelligence and Machine Learning algorithms and its alliance with Computational Mechanics and Optimisation tools. However, a key aspect with industrial design is the scarcity of available data, making it problematic to rely on deep-learning approaches. Assuming that the existing designs live in a manifold, in this paper, we propose a synergistic use of existing Machine Learning tools to infer a reduced manifold from the existing limited set of designs and, then, to use it to interpolate between the individuals, working as a generator basis, to create new and coherent designs. For this, a key aspect is to be able to properly interpolate in the reduced manifold, which requires a proper clustering of the individuals. From our experience, due to the scarcity of data, adding topological descriptors to geometrical ones considerably improves the quality of the clustering. Thus, a distance, mixing topology and geometry is proposed. This distance is used both, for the clustering and for the interpolation. For the interpolation, relying on optimal transport appear to be mandatory. Examples of growing complexity are proposed to illustrate the goodness of the method

    Manifold learning for coherent design interpolation based on geometrical and topological descriptors

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    [EN] In the context of intellectual property in the manufacturing industry, know-how is referred to practical knowledge on how to accomplish a specific task. This know-how is often difficult to be synthesised in a set of rules or steps as it remains in the intuition and expertise of engineers, designers, and other professionals. Today, a new research line in this concern spot-up thanks to the explosion of Artificial Intelligence and Machine Learning algorithms and its alliance with Computational Mechanics and Optimisation tools. However, a key aspect with industrial design is the scarcity of available data, making it problematic to rely on deep-learning approaches. Assuming that the existing designs live in a manifold, in this paper, we propose a synergistic use of existing Machine Learning tools to infer a reduced manifold from the existing limited set of designs and, then, to use it to interpolate between the individuals, working as a generator basis, to create new and coherent designs. For this, a key aspect is to be able to properly interpolate in the reduced manifold, which requires a proper clustering of the individuals. From our experience, due to the scarcity of data, adding topological descriptors to geometrical ones considerably improves the quality of the clustering. Thus, a distance, mixing topology and geometry is proposed. This distance is used both, for the clustering and for the interpolation. For the interpolation, relying on optimal transport appear to be mandatory. Examples of growing complexity are proposed to illustrate the goodness of the method.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).The authors gratefully acknowledge the financial support of Ministerio de Educacion, Spain (FPU16/07121),Generalitat Valenciana, Spain (Prometeo/2021/046 and CIAICO/2021/226), Ministerio de Economia, Industriay Competitividad, Spain (DPI2017-89816-R) and FEDER. O. Allix would like to thank the French National University Council and ENS Paris-Saclay for supporting his sabbatical at UPV, which made it possible to closely interact with the colleagues from I2MB-UPV. Funding for open access charge: CRUE-Universitat Politecnica de ValenciaMuñoz-Pellicer, D.; Allix, O.; Chinesta Soria, FJ.; Ródenas, JJ.; Nadal, E. (2023). Manifold learning for coherent design interpolation based on geometrical and topological descriptors. Computer Methods in Applied Mechanics and Engineering. 405. https://doi.org/10.1016/j.cma.2022.11585940

    Symbiosis of the endangered Lupinus mariae-josephae lupin especies: Successful "in situ" propagation with rhizobial inoculation

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    Region, in Eastern Spain. This lupine thrives in alkaline soils with high pH, a unique habitat for lupines. In these soils, Lmj grows in just a few defined patches, and previous conservation efforts directed towards controlled plant reproduction have been unsuccessful. A legislative decree (70/2009, page 20156 Anex I) published in the el 'Diario Oficial de la Comunitat Valenciana' shows Lmj in a category corresponding, in the latest version of the Red List of IUCN (IUCN, 2012) (International Union for Conservation of Nature and Nature Resources), to an ?Endangered? legume species not extinct in the wild. Most current IUCN criteria used to define rare, small-range legume species, are based on history of reproductive traits such as number of pods and seeds. We have previously shown that Lmj plants establish a specific root nodule symbiosis with bradyrhizobia present in those soils, and we reasoned that the paucity of these bacteria in soils might contribute to the lack of success in reproducing plants for conservation purposes. Greenhouse experiments using Lmj trap-plants showed an absence, or very low concentration, of Lmj-nodulating bacteria in ?terra rossa? soils of Valencia outside of Lmj plant patches. No Lmj endosymbiotic bacteria were found in ?terra rossa? or alkaline red soils outside the Valencia Lmj endemism region in the Iberian Peninsula or Balearic Islands. Among the rhizobia able to establish an efficient symbiosis with L. mariae-josephae plants, two Bradyrhizobium sp. strains, LmjC and LmjM3, were selected as inocula for seed coating. Two planting experiments were carried out in consecutive years under natural conditions in areas with edapho-climatic characteristics identical to those sustaining natural Lmj populations, and successful reproduction of the plant was achieved. Interestingly, the successful reproductive cycle was absolutely dependent on seedling inoculation with effective bradyrhizobia, and optimal performance was observed in plants inoculated with LmjC, a strain that had previously shown the most efficient behavior under controlled conditions. These results define conditions for L. mariae-josephae conservation and for extension to alkaline-limed soil habitats, where no other known lupine can thrive. Broadly speaking, the work singularly identified the rhizobial symbiosis as a factor affecting the conservation of legumes and often being exceedingly vulnerable to threats. Our results also indicate that seed inoculation with N2-fixing, efficient Rhizobium strains is a strategy to consider in the conservation of endangered legume specie

    Endangered Lupinus mariae-josephae species: conservation efforts

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    A lupin endemism, Lupinus mariae-josephae (Lmj), singularly has been identified in the Valencia province, in Eastern Spain. This lupin thrives in alkaline-limed soils with high pH, a unique habitat for lupins, from a small area in Valencia region. In these soils, Lmj grows in just a few small, defined patches, and previous conservation efforts directed towards controlled plant reproduction have been unsuccessful. This lupin was thought to be extinct in Valencia until 2007, when it was discovered in a limestone patch. The reasons behind Lmj endangered status are presently unknown. This study will focus on the symbiosis between Lmj and rhizobia, and how this relationship might impact the population size of Lmj. We have previously shown that Lmj plants establish a specific root nodule symbiosis with bradyrhizobia present in those soils, and we reasoned that the paucity of these bacteria in soils might contribute to the lack of success in reproducing plants for conservation purposes

    H-adaptive Mesh Refinement for Topology Optimization in the Framework of the Cartesian Grid finite Element Method - cgFEM

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    The growing interest in Topological Optimization (TO) in recent years is undeniable. In particular, this paper focuses on the Solid Isotropic Material Penalization (SIMP) method, broadly used because of its simple formulation and efficiency, and how h-adaptive mesh refinement in the context of the Cartesian grid finite element method, cgFEM, can improve its performance. This paper will present a combination of three methodologies based on mesh h-adaptation in cgFEM (whose hierarchical mesh and data structures are especially efficient in TO) to overcome two disadvantages of the SIMP method related to the lack of sharpness in the definition of the boundary and the influence of the finite element (FE) discretization on the final solution: 1) Use of two mesh levels: i) a mesh for the FE analysis and ii) a refined mesh, not only for integration and calculation of sensitivities but also to enhance sharpness of the boundary representation at a marginal computational cost. 2) Use a density-based refinement: a sharper boundary definition will be obtained using a basic technique where elements with intermediate density values are refined. 3) Use of solution-based refinement: the numerical solution obtained by the use of a h-adaptive analysis technique based on a recovery-type error estimator guaranties that an accurate evaluation of stress values is considered in stress-constrained TO

    Phenotypic and molecular diversity of Lupinus mariae-josephi endosymbiotic bacteria.

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    Lupinus mariae-josephi is a new Lupinus species recently described in a Southeastern area of Spain (Valencia) in soils of singularly high pH and active lime content. Bacteria from L. mariaejosephi have been isolated and correspond to extra-slow growing bacteria symbiotically and phylogenetically distant to endosymbiotic strains nodulating other Lupinus sp. native of the Iberian Peninsula and adapted to growth in acid soils. Cross-inoculation experiments revealed that the L. mariae-josephi endosymbiotic bacteria are unable to nodulate or efficiently fix nitrogen with well-known Lupinus spp. Their species affiliation was examined by a multilocus sequence analysis of four housekeeping genes (16S rDNA, glnII, recA, atpD) and the symbiotic nodC gene. Single and concatenated phylogenetic analyses of these genes consistently revealed that L. mariae-josephi endosymbiotic bacteria belong to a clade, within the Bradyrhizobium genus, highly differentiated from the Bradyrhizobium clade that includes currently named Bradyrhizobium species as well as the endosymbiotic bacteria from Lupinus species tested in this study. Within this new clade the L. mariae-josephi bacteria nested in several subgroups that may correspond to novel sister species. The phylogenetic analysis based on the nodC gene showed that L. mariae-josephi endosymbiotic bacteria define a novel branch in the nodC Bradyrhizobium tree and likely have a common unique ancestor for the symbiotic genes with nodule isolates from Retama spp. At this moment two draft genome sequences belonging to a Bradyrhizobium isolated from L. angustifolius (ISLU101) and to a Bradyrhizobium isolated from L. mariae-josephi (LmjC) have been obtained. The first analysis showed that both genomes correspond to very large chromosomes (>8000 genes) with a high number of unique proteins. nod genes organization are highly conserved among ISLU101, LmjC and B. japonicum USDA110. LmjC presents a single cluster with nod genes from diverse origins. ISLU101 fix genes are found in a single cluster homologous to that of USDA110. LmjC possess a complete copy of fix genes homologous to that from USDA110 and an incomplete one similar to S. meliloti. LmjC possess TypeIII and TypeIV secretion systems. ISLU101 has a Type IV homologous to that of photosynthetic Bradyrhizobium BTAi1, and two copies of Type VI, one homologous to that of USDA110 and the other to R. leguminosarum. Preliminary data indicate that ISLU101 contains a potential second replicon (~100 genes) with high homology to Bradyrhizobium BTai1 plasmid sequenc
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