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  • Publication . Conference object . Research . 2018
    Restricted English
    Authors: 
    Livesu, M.; Cabiddu, D.; Attene, M.;
    Publisher: The Eurographics Association, Goslar, DEU
    Country: Italy
    Project: EC | CAxMan (680448)

    Accurately simulating Additive Manufacturing (AM) processes is useful to predict printing failures and test 3D printing without wasting precious resources, both in terms of time ad material. In AM the object to be fabricated is first cut into a set of slices aligned with the build direction, and then printed, depositing or solidifying material one layer on top of the other. To guarantee accurate simulations, it is therefore necessary to encode the temporal evolution of the shape to be printed within the simulation domain. We introduce slice2mesh, to the best of our knowledge the first software capable of turning a sliced object directly into a volumetric mesh. Our tool inputs a set of slices and produces a tetrahedral mesh that endows each slice in its connectivity. An accurate representation of the simulation domain at any time during the print can therefore be easily obtained by filtering out the slices yet to be processed. slice2mesh also features a flexible mesh generation system for external supports, and allows the user to trade accuracy for simplicity by producing approximate simulation domains obtained by filtering the object in slice space. Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Picture/Image Generation-Line and curve generation Smart Tools and Apps for Graphics - Eurographics Italian Chapter Conference M. Livesu, D. Cabiddu, and M. Attene Manufacturing Objects 23 13

  • Open Access English
    Authors: 
    Tsitsokas, Dimitrios; Kouvelas, Anastasios; id_orcid0000-0003-4571-2530; Geroliminis, Nikolas;
    Publisher: ETH Zurich
    Country: Switzerland
    Project: EC | DIT4TraM (953783)

    Traffic-responsive signal control is a cost-effective and easy-to-implement network management strategy with high potential in improving performance in congested networks with dynamic characteristics. Max Pressure (MP) distributed controller gained significant popularity due to its theoretically proven ability of queue stabilization and throughput maximization under specific assumptions. However, its effectiveness under saturated conditions is questionable, while network-wide application is limited due to high instrumentation cost. Perimeter control (PC) based on the concept of the Macroscopic Fundamental Diagram (MFD) is a state-of-the-art aggregated strategy that regulates exchange flows between regions, in order to maintain maximum regional travel production and prevent over-saturation. Yet, homogeneity assumption is hardly realistic in congested states, thus compromising PC efficiency. In this paper, the effectiveness of network-wide, parallel application of PC and MP embedded in a two-layer control framework is assessed with mesoscopic simulation. Aiming at reducing implementation cost of MP without significant performance loss, we propose a method to identify critical nodes for partial MP deployment. A modified version of Store-and-forward paradigm incorporating finite queue and spill-back consideration is used to test different configurations of the proposed framework, for a real large-scale network, in moderately and highly congested scenarios. Results show that: (i) combined control of MP and PC outperforms separate MP and PC applications in both demand scenarios; (ii) MP control in reduced critical node sets leads to similar or even better performance compared to full-network implementation, thus allowing for significant cost reduction; iii) the proposed control schemes improve system performance even under demand fluctuations of up to 20% of mean. arXiv

  • Open Access English
    Authors: 
    Jürgen Zechner; Lars Kielhorn; Thomas Rüberg; Soner Steiner;
    Publisher: Zenodo
    Project: EC | PRACE-6IP (823767)

    TAILSIT is a company based in Graz, Austria, that produces custom-fit simulation software tools for computational electromagnetics and structural analysis. Its unique selling proposition is a numerical software library based on a coupled Finite/Boundary Element Method (FEM/BEM) for the efficient analysis of electromagnetic problems. A major building block of the software is represented by the BEM which, in its naive implementation, has a quadratic complexity: runtime and memory requirements scale with the second power of the system size. In order to overcome this limitation, TAILSIT uses the Fast Multipole Method (FMM) where the scaling of the computational costs reduce to almost linear complexity. But even with this acceleration technique, the use of the BEM is rather limited on an average desktop workstation. During this SHAPE project TAILSIT’s electromagnetic simulation software has been ported to HPC machines with the support of the Vienna Scientific Cluster (VSC, https://vsc.ac.at) at TU Wien and using their computing resources. Thorough performance analyses have led to significant runtime improvements and a good overall scaling for up to a few thousand CPUs. Whereas TAILSIT’s previous implementation of the FMM could handle about 106 degrees of freedom, within this project we achieved problem sizes of up to 50 · 10.

  • Open Access French
    Authors: 
    Navez, Brigitte; Cottet, Valentine; Tisiot, Raphael; Causse, Mathilde; Fontanet, Lilian;
    Publisher: HAL CCSD
    Country: France
    Project: EC | TRADITOM (634561)
  • Publication . Report . Conference object . Research . 2018
    Open Access English
    Authors: 
    Jaap van Milgen;
    Publisher: HAL CCSD
    Country: France
    Project: EC | Feed-a-Gene (633531)

    International audience

  • Publication . Research . 2016
    Open Access
    Authors: 
    Monge-Naranjo, Alexander; Sanchez, Juan M.; Santaeulalia-Llopis, Raul;
    Country: Spain
    Project: EC | ADEMU (649396)

    Are production factors allocated efficiently across countries? To differentiate misallocation from factor intensity differences, we construct a new dataset of estimates for the output shares of natural resources for a large panel of countries. We find a significant and persistent degree of misallocation of physical capital. We also find a remarkable movement toward efficiency during last 35 years, associated with the elimination of interventionist policies and driven by domestic accumulation. In contrast, we find a much larger and persistent misallocation of human capital. Interestingly, when both production factors can be reallocated, capital would often flow from poor to rich countries. The ADEMU Working Paper Series is being supported by the European Commission Horizon 2020 European Union funding for Research & Innovation, grant agreement No 649396.

  • Publication . Research . Other literature type . 2019
    Open Access English
    Authors: 
    Kannan, Venkatesh; Borrell, Ricard; Doyle, Myles; Houzeaux, Guillaume;
    Publisher: Zenodo
    Project: EC | PRACE-5IP (730913)

    High Performance Computing (HPC) applications are highly complex and demand ecient execution. Energy require- ment of current petascale and future exascale systems is a major cause for concern, and it is crucial to improve the energy-eciency of the applications that run on these systems. A signi cant source of improvement for applications is that they commonly exhibit dynamic resource requirements. Consequently, such dynamism in an application presents opportunity to tailor the utilisation of resources in the HPC system based on the requirements of the application at runtime. READEX (Runtime Exploitation of Application Dynamism for Energy-ecient eXascale computing) is a EU Horizon 2020 FET-HPC project whose objective is to exploit the dynamism found in HPC applications at runtime to achieve ecient computation on exascale systems. Alya is a high performance computational mechanics application that is present in the Uni ed European Application Benchmark Suite and the PRACE Accelerator Benchmark Suite. In this paper, we apply the READEX methodology on Alya to identify and exploit any dynamism that is exhibited. We report on the potential energy savings and the e ects on the application runtime, where we observe 5-20% reduction in the energy consumed by the application.

  • Open Access
    Authors: 
    Martos-Sitcha, Juan; Bermejo-Nogales, Azucena; Calduch-Giner, Josep; PĂŠrez-SĂĄnchez, Jaume;
    Publisher: Figshare
    Project: EC | AQUAEXCEL2020 (652831)

    Forward (F) and reverse (R) primers used for real-time PCR. (DOCX 50Â kb)

  • Open Access English
    Authors: 
    Krotkiewski, Marcin;
    Publisher: Zenodo
    Project: EC | PRACE-5IP (730913)

    Various optimizations of the ART software package for the solution of the radiative transfer equation in three dimensions are discussed in this white paper. All critical path functions of the code have been optimized and vectorized using OpenMP directives. Several techniques have been used, amongst others the rearrangement of input data and internal data structures to facilitate usage of CPU vector units, vectorization of calls to the math library, explicit loop unrolling to allow vectorization of iterative loops with a convergence criterion, vectorization of data-dependent if-statements through enforced computations on all SIMD lanes and filtering of the final result. Several technical challenges had to be overcome to achieve the best performance. The OpenMPI stack needed to be compiled with a custom (non-native) Glibc library. In some cases, individual vectorized clones generated automatically by the compilers needed to be substituted with custom functions implemented manually using compiler intrinsics. Performance tests have shown that on the Broadwell architecture the optimized code works from 2.5x faster (RT solver) to 13x faster (EOS solver) on a single core. MPI implementation of the code scales with 95% efficiency on 2048 cores. Throughout the project, several GCC bugs related to automatic OpenMP vectorization have been reported, which shows that the support for the relatively new OpenMP vectorization features is still not mature. For some of those bugs effective workarounds have been developed. We also point to some shortcomings in the OpenMP simd vectorization framework and develop several new optimization techniques, which improve effectiveness of automatic code vectorization. Finally, some generally useful tutorials have been delivered.

  • Open Access English
    Authors: 
    Soares Martins Neto, Antonio; Mathew, Nanditha; Mohnen, Pierre; Treibich, Tania;
    Publisher: Munich: Center for Economic Studies and ifo Institute (CESifo)
    Country: Netherlands
    Project: EC | GROWINPRO (822781)

    This paper analyses the evidence of job polarization in developing countries. We carry out an extensive review of the existing empirical literature and examine the primary data sources and measures of routine intensity. The synthesis of results suggests that job polarization in emerging economies is only incipient compared to other advanced economies. We then examine the possible moderating aspects preventing job polar- ization, discussing the main theoretical channels and the existing empirical literature. Overall, the literature relates the lack of polarization as a natural consequence of lim- ited technology adoption and the offshoring of routine, middle-earning jobs to some host developing economies. In turn, the limited technology adoption results from sub- optimal capabilities in those economies, including the insufficient supply of educated workers. Finally, we present the main gaps in the literature in developing economies and point to the need for more micro-level studies focusing on the impacts of tech- nology adoption on workers’ careers and studies exploring the adoption and use of technologies at the firm level.

Advanced search in
Research products
arrow_drop_down
Searching FieldsTerms
Any field
arrow_drop_down
includes
arrow_drop_down
Include:
742 Research products, page 1 of 75
  • Publication . Conference object . Research . 2018
    Restricted English
    Authors: 
    Livesu, M.; Cabiddu, D.; Attene, M.;
    Publisher: The Eurographics Association, Goslar, DEU
    Country: Italy
    Project: EC | CAxMan (680448)

    Accurately simulating Additive Manufacturing (AM) processes is useful to predict printing failures and test 3D printing without wasting precious resources, both in terms of time ad material. In AM the object to be fabricated is first cut into a set of slices aligned with the build direction, and then printed, depositing or solidifying material one layer on top of the other. To guarantee accurate simulations, it is therefore necessary to encode the temporal evolution of the shape to be printed within the simulation domain. We introduce slice2mesh, to the best of our knowledge the first software capable of turning a sliced object directly into a volumetric mesh. Our tool inputs a set of slices and produces a tetrahedral mesh that endows each slice in its connectivity. An accurate representation of the simulation domain at any time during the print can therefore be easily obtained by filtering out the slices yet to be processed. slice2mesh also features a flexible mesh generation system for external supports, and allows the user to trade accuracy for simplicity by producing approximate simulation domains obtained by filtering the object in slice space. Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Picture/Image Generation-Line and curve generation Smart Tools and Apps for Graphics - Eurographics Italian Chapter Conference M. Livesu, D. Cabiddu, and M. Attene Manufacturing Objects 23 13

  • Open Access English
    Authors: 
    Tsitsokas, Dimitrios; Kouvelas, Anastasios; id_orcid0000-0003-4571-2530; Geroliminis, Nikolas;
    Publisher: ETH Zurich
    Country: Switzerland
    Project: EC | DIT4TraM (953783)

    Traffic-responsive signal control is a cost-effective and easy-to-implement network management strategy with high potential in improving performance in congested networks with dynamic characteristics. Max Pressure (MP) distributed controller gained significant popularity due to its theoretically proven ability of queue stabilization and throughput maximization under specific assumptions. However, its effectiveness under saturated conditions is questionable, while network-wide application is limited due to high instrumentation cost. Perimeter control (PC) based on the concept of the Macroscopic Fundamental Diagram (MFD) is a state-of-the-art aggregated strategy that regulates exchange flows between regions, in order to maintain maximum regional travel production and prevent over-saturation. Yet, homogeneity assumption is hardly realistic in congested states, thus compromising PC efficiency. In this paper, the effectiveness of network-wide, parallel application of PC and MP embedded in a two-layer control framework is assessed with mesoscopic simulation. Aiming at reducing implementation cost of MP without significant performance loss, we propose a method to identify critical nodes for partial MP deployment. A modified version of Store-and-forward paradigm incorporating finite queue and spill-back consideration is used to test different configurations of the proposed framework, for a real large-scale network, in moderately and highly congested scenarios. Results show that: (i) combined control of MP and PC outperforms separate MP and PC applications in both demand scenarios; (ii) MP control in reduced critical node sets leads to similar or even better performance compared to full-network implementation, thus allowing for significant cost reduction; iii) the proposed control schemes improve system performance even under demand fluctuations of up to 20% of mean. arXiv

  • Open Access English
    Authors: 
    Jürgen Zechner; Lars Kielhorn; Thomas Rüberg; Soner Steiner;
    Publisher: Zenodo
    Project: EC | PRACE-6IP (823767)

    TAILSIT is a company based in Graz, Austria, that produces custom-fit simulation software tools for computational electromagnetics and structural analysis. Its unique selling proposition is a numerical software library based on a coupled Finite/Boundary Element Method (FEM/BEM) for the efficient analysis of electromagnetic problems. A major building block of the software is represented by the BEM which, in its naive implementation, has a quadratic complexity: runtime and memory requirements scale with the second power of the system size. In order to overcome this limitation, TAILSIT uses the Fast Multipole Method (FMM) where the scaling of the computational costs reduce to almost linear complexity. But even with this acceleration technique, the use of the BEM is rather limited on an average desktop workstation. During this SHAPE project TAILSIT’s electromagnetic simulation software has been ported to HPC machines with the support of the Vienna Scientific Cluster (VSC, https://vsc.ac.at) at TU Wien and using their computing resources. Thorough performance analyses have led to significant runtime improvements and a good overall scaling for up to a few thousand CPUs. Whereas TAILSIT’s previous implementation of the FMM could handle about 106 degrees of freedom, within this project we achieved problem sizes of up to 50 · 10.

  • Open Access French
    Authors: 
    Navez, Brigitte; Cottet, Valentine; Tisiot, Raphael; Causse, Mathilde; Fontanet, Lilian;
    Publisher: HAL CCSD
    Country: France
    Project: EC | TRADITOM (634561)
  • Publication . Report . Conference object . Research . 2018
    Open Access English
    Authors: 
    Jaap van Milgen;
    Publisher: HAL CCSD
    Country: France
    Project: EC | Feed-a-Gene (633531)

    International audience

  • Publication . Research . 2016
    Open Access
    Authors: 
    Monge-Naranjo, Alexander; Sanchez, Juan M.; Santaeulalia-Llopis, Raul;
    Country: Spain
    Project: EC | ADEMU (649396)

    Are production factors allocated efficiently across countries? To differentiate misallocation from factor intensity differences, we construct a new dataset of estimates for the output shares of natural resources for a large panel of countries. We find a significant and persistent degree of misallocation of physical capital. We also find a remarkable movement toward efficiency during last 35 years, associated with the elimination of interventionist policies and driven by domestic accumulation. In contrast, we find a much larger and persistent misallocation of human capital. Interestingly, when both production factors can be reallocated, capital would often flow from poor to rich countries. The ADEMU Working Paper Series is being supported by the European Commission Horizon 2020 European Union funding for Research & Innovation, grant agreement No 649396.

  • Publication . Research . Other literature type . 2019
    Open Access English
    Authors: 
    Kannan, Venkatesh; Borrell, Ricard; Doyle, Myles; Houzeaux, Guillaume;
    Publisher: Zenodo
    Project: EC | PRACE-5IP (730913)

    High Performance Computing (HPC) applications are highly complex and demand ecient execution. Energy require- ment of current petascale and future exascale systems is a major cause for concern, and it is crucial to improve the energy-eciency of the applications that run on these systems. A signi cant source of improvement for applications is that they commonly exhibit dynamic resource requirements. Consequently, such dynamism in an application presents opportunity to tailor the utilisation of resources in the HPC system based on the requirements of the application at runtime. READEX (Runtime Exploitation of Application Dynamism for Energy-ecient eXascale computing) is a EU Horizon 2020 FET-HPC project whose objective is to exploit the dynamism found in HPC applications at runtime to achieve ecient computation on exascale systems. Alya is a high performance computational mechanics application that is present in the Uni ed European Application Benchmark Suite and the PRACE Accelerator Benchmark Suite. In this paper, we apply the READEX methodology on Alya to identify and exploit any dynamism that is exhibited. We report on the potential energy savings and the e ects on the application runtime, where we observe 5-20% reduction in the energy consumed by the application.

  • Open Access
    Authors: 
    Martos-Sitcha, Juan; Bermejo-Nogales, Azucena; Calduch-Giner, Josep; PĂŠrez-SĂĄnchez, Jaume;
    Publisher: Figshare
    Project: EC | AQUAEXCEL2020 (652831)

    Forward (F) and reverse (R) primers used for real-time PCR. (DOCX 50Â kb)

  • Open Access English
    Authors: 
    Krotkiewski, Marcin;
    Publisher: Zenodo
    Project: EC | PRACE-5IP (730913)

    Various optimizations of the ART software package for the solution of the radiative transfer equation in three dimensions are discussed in this white paper. All critical path functions of the code have been optimized and vectorized using OpenMP directives. Several techniques have been used, amongst others the rearrangement of input data and internal data structures to facilitate usage of CPU vector units, vectorization of calls to the math library, explicit loop unrolling to allow vectorization of iterative loops with a convergence criterion, vectorization of data-dependent if-statements through enforced computations on all SIMD lanes and filtering of the final result. Several technical challenges had to be overcome to achieve the best performance. The OpenMPI stack needed to be compiled with a custom (non-native) Glibc library. In some cases, individual vectorized clones generated automatically by the compilers needed to be substituted with custom functions implemented manually using compiler intrinsics. Performance tests have shown that on the Broadwell architecture the optimized code works from 2.5x faster (RT solver) to 13x faster (EOS solver) on a single core. MPI implementation of the code scales with 95% efficiency on 2048 cores. Throughout the project, several GCC bugs related to automatic OpenMP vectorization have been reported, which shows that the support for the relatively new OpenMP vectorization features is still not mature. For some of those bugs effective workarounds have been developed. We also point to some shortcomings in the OpenMP simd vectorization framework and develop several new optimization techniques, which improve effectiveness of automatic code vectorization. Finally, some generally useful tutorials have been delivered.

  • Open Access English
    Authors: 
    Soares Martins Neto, Antonio; Mathew, Nanditha; Mohnen, Pierre; Treibich, Tania;
    Publisher: Munich: Center for Economic Studies and ifo Institute (CESifo)
    Country: Netherlands
    Project: EC | GROWINPRO (822781)

    This paper analyses the evidence of job polarization in developing countries. We carry out an extensive review of the existing empirical literature and examine the primary data sources and measures of routine intensity. The synthesis of results suggests that job polarization in emerging economies is only incipient compared to other advanced economies. We then examine the possible moderating aspects preventing job polar- ization, discussing the main theoretical channels and the existing empirical literature. Overall, the literature relates the lack of polarization as a natural consequence of lim- ited technology adoption and the offshoring of routine, middle-earning jobs to some host developing economies. In turn, the limited technology adoption results from sub- optimal capabilities in those economies, including the insufficient supply of educated workers. Finally, we present the main gaps in the literature in developing economies and point to the need for more micro-level studies focusing on the impacts of tech- nology adoption on workers’ careers and studies exploring the adoption and use of technologies at the firm level.

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