JANUS: an FPGA-based System for High Performance Scientific Computing

This paper describes JANUS, a modular massively parallel and reconfigurable FPGA-based computing system. Each JANUS module has a computational core and a host. The computational core is a 4x4 array of FPGA-based processing elements with nearest-neighbor data links. Processors are also directly connected to an I/O node attached to the JANUS host, a conventional PC. JANUS is tailored for, but not limited to, the requirements of a class of hard scientific applications characterized by regular code structure, unconventional data manipulation instructions and not too large data-base size. We discuss the architecture of this configurable machine, and focus on its use on Monte Carlo simulations of statistical mechanics. On this class of application JANUS achieves impressive performances: in some cases one JANUS processing element outperfoms high-end PCs by a factor ~ 1000. We also discuss the role of JANUS on other classes of scientific applications.Comment: 11 pages, 6 figures. Improved version, largely rewritten, submitted to Computing in Science & Engineerin

The apeNEXT project

Numerical simulations in theoretical high-energy physics (Lattice QCD) require huge computing resources. Several generations of massively parallel computers optimised for these applications have been developed within the APE (array processor experiment) project. Large prototype systems of the latest generation, apeNEXT, are currently being assembled and tested. This contribution explains how the apeNEXT architecture is optimised for Lattice QCD, provides an overview of the hardware and software of apeNEXT, and describes its new features, like the SPMD programming model and the C compiler

Acupuncture for paroxysmal and persistent atrial fibrillation: An effective non-pharmacological tool?

In Traditional Chinese Medicine, stimulation of the Neiguan spot has been utilized to treat palpitations and symptoms related to different cardiovascular diseases. We evaluated whether acupuncture might exert an antiarrhythmic effect on patients with paroxysmal or persistent atrial fibrillation (AF). Two sets of data are reviewed. The first included patients with persistent AF who underwent electrical cardioversion to restore sinus rhythm. The second included patients with symptomatic paroxysmal AF. All subjects had normal ventricular function. Acupuncture treatment consisted of 10 acupuncture sessions on a once a week basis with puncturing of the Neiguan, Shenmen and Xinshu spots. In patients with persistent AF, the recurrence rate after acupuncture treatment was similar to that observed in patients on amiodarone, but significantly smaller than that measured after sham acupuncture treatment or in the absence of any antiarrhythmic drugs. In a small group of patients with paroxysmal AF, acupuncture resulted in a significant reduction in the number and duration of symptomatic AF episodes. In conclusion, we observed that acupuncture of the Neiguan spot was associated with an antiarrhythmic effect, which was evident in patients with both persistent and paroxysmal AF. These preliminary data, observed in 2 small groups of AF patients, need to be validated in a larger population but strongly suggest that acupuncture may be an effective non-invasive and safe antiarrhythmic tool in the management of these patients

Monte Carlo simulations of spin glass systems on the cell broadband engine

We implement a Monte Carlo algorithm for spin glass systems and optimize for the Cell-BE processor, assessing the effectiveness of this architecture for state-of-the-art simulations. Recent developments in many-core processor architectures, like the IBM Cell BE seem to open new opportunities in this field, where computational requirements are so demanding that state-of-the-art simulations often use dedicated computing systems. We present our implementation, analyze results and compare performances with those of both commodity processors and dedicated systems. © 2010 Springer-Verlag Berlin Heidelberg

Durability of reinforced concrete containing biochar

none10Research carried out in the scope of the IMPRESA project supported by POR-FESR 2014-2020 funds (Call 2018)Recently, within the field of new cementitious building materials development, there has been a grow-ing interest in the use of biochar, which represents the solid by-product resulting from biomass pyrol-ysis or gasification processes. The addition of biochar particles into concrete admixures can offer an eco-friendly carbon sequestration solution while possibly improving concrete mechanical properties. However, the role of biochar on durability of concrete and steel corrosion is still unexplored. Within this context, this work presents the first results in terms of corrosion potentials (Ecor) polarization resistance (Rp) measurements and electrochemical impedance spectroscopy (EIS) recording, of an extensive study on the influence of biochar as a concrete additive during wet and dry (w/d) exposures in saturated Ca(OH)2 solution, containing 0.1 N CaCl2.mixedFederica Zanotto, Alice Sirico, Francesca Vecchi, Andrea Balbo, Patrizia Bernardi, Beatrice Belletti, Alessio Malcevschi, Vincenzo Grassi, Sebastiano Merchiori, Cecilia MonticelliZanotto, Federica; Sirico, Alice; Vecchi, Francesca; Balbo, Andrea; Bernardi, Patrizia; Belletti, Beatrice; Malcevschi, Alessio; Grassi, Vincenzo; Merchiori, Sebastiano; Monticelli, Cecili