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Parallel Computing represents a valid solution for reducing execution times in simulations of complex geological processes, such as lava flows, debris flows and, in general, of fluid-dynamic processes. In these cases, Cellular Automata (CA) models have proved to be effective when the behavior of the system to be modeled can be described in terms of local interactions among its constituent parts. Cellular Automata are parallel computing models, discrete in space and time; space is generallydoi:10.1016/j.procs.2011.04.029 fatcat:nri36tlunbct5ffgjmlj74j6km
more »... vided into cells of uniform size and the overall dynamics of the system emerges as the result of the simultaneous application, at discrete time steps, of proper local rules of evolution to each one of them. Due to their intrinsic parallelism, CA models are attractive since they are suitable to be effectively and naturally implemented on parallel computers achieving also high performance. In the recent past, CA models were efficiently executed on distributed memory architectures, such as Beowulf clusters and many-node Supercomputers, while fewer implementations are found regarding shared-memory computers, such as in multi-core machines. This paper shows performance results of the parallelization of a well-known CA model for simulating lava flowsthe SCIARA modelin a shared memory environment, by means of OpenMP, an Application Programming Interface which supports multiplatform shared-memory parallel programming. needed in this latter phase depends on the kind of available parallel architecture. For instance, in case of a distributed memory machine, this can be accomplished by means of MPI -Message Passing Interface  . At the contrary, if a multicore (and shared memory) architecture machine is available, a shared-memory or multithread implementation can result in a better and more efficient solution. In this latter specific field of parallel systems, OpenMP  defines specifications for parallelizing programs in a shared memory environment. In particular, OpenMP represents the most widely adopted solution where compiler directives and environment variables specify shared-memory parallelism in a quasi-transparent way. The study of geological processes is of increasing interest for the Scientific Community both for theoretical aspects and possible practical applications related to risk assessment and mitigation. Through the simulations of reliable models, risks associated to such processes can be evaluated and possible countermeasures can be conjectured and tested. Among different methodologies used for modeling these type of phenomena (and thus related to the Computational Science field) such as numerical analysis, high order difference approximations and finite differences, Cellular Automata (CA)  proved to be particularly suitable when the behavior of the system to be modeled can be described in terms of local interactions. Originally introduced by von Neumann in the 50s to study self-reproduction issues, CA are discrete computational models, widely utilized for modeling and simulating complex systems. Well known examples are Lattice Gas Automata and Lattice Boltzmann models  which are particularly suitable for modeling fluid dynamics at a microscopic level of description. However, many complex phenomena (e.g. landslides or lava flows) are difficult to be modeled at such scale, as they generally evolve on large areas, thus needing a macroscopic level of description. Moreover, they may be also difficult to be modeled through standard approaches, such as differential equations (cf.  for the case of lava flows), and Macroscopic Cellular Automata (MCA)  can represent a valid alternative. As the name suggests, the main features of the phenomena of interest can be directly described at a macroscopic level (e.g. average amount of lava, temperature, etc), thus disregarding microscopic aspects. Well known examples of MCA applications include the simulation of lava , debris flows , pyroclastic flows , density currents , water flux in unsaturated soils , Artificial Life systems  and forest fires , besides many others. Refer to  for a more detailed description, besides theoretical aspects on MCA and, for instance, to the ACRI conference (e.g. ) series for up-to-date general CA applications interested by the International Scientific Community. Several successful attempts have been carried out regarding solutions for automatically parallelizing MCA simulation models. Among others, CAMELot  and libAuToti  represent valid solutions for implementing MCA models on distributed memory machines, such as Beowulf clusters and Supercomputers, where good performances where achieved. Notwithstanding, with the emergence of multi-processor computers, multithreaded programming is quickly gaining popularity and the adoption of shared-memory programming implementations could be more appropriate for these architectures. Nonetheless, few valid OpenMP parallelizations have been implemented for CA-like models, such as for fire spread simulation  or as in  where interesting results were obtained for the parallelization of Lattice Boltzmann models. This paper presents first results related to the parallelization, in shared memory environments, of a well-known, reliable and efficient model widely adopted for lava flow risk assessment, the SCIARA MCA model. First tests have shown the validity of this kind of approach that can be considered also effective for hybrid parallel solutions (i.e. jointly usage of MPI and OpenMP). In the following, after a brief description of the latest version of the SCIARA MCA model for lava flows, a quick overview of the shared memory paradigm and of the OpenMP library are presented. Subsequently, the specific implementation and performance analysis referred to simulations of three real lava flow events occurred on Mt. Etna (Italy) are shown, while conclusions are reported at the end of the paper.
Azulay • Anna Bartkiewicz • Ilse van Bemmel • Rob Beswick • Tatiana Bocanegra • Biagina Boccardi • Tamara Bogdanović • Walter Brisken • Paola Castangia • Patrick Charlot • James Chibueze • Giuseppe ... Figure 1 . 3 : 13 Global VLBI (EVN, VLBA and GBT) observations of the gravitationally lensed radio source MG J0751+2716 taken at 1.7 GHz(Fig. 1, Spingola et al. 2018) . ...arXiv:2007.02347v1 fatcat:lg6hkimlobf7rlw73dgufj27bm
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Party founded in 1944 by Togliatti, Rinascita, dedicated an article to Memoriale in which Volponi was called upon to answer the questions of industry workers and employees (No author 1962; Camon 1969; Spingola ... Giuseppe Pedriali defines Ottieri's writing as expression of "autobiografismo" (Pedriali 1995) , while Paolo Milano draws attention to the mixture of "autobiografia e cronaca" (Milano 1962) . ...doi:10.1080/00751634.2020.1695876 fatcat:drwa7h3nhjfy7ab7zg7pnbdmce
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Come rilevano Tatti (2020) e Spingola (2020), le modifiche introdotte nella prima prova scritta attestano la rilevanza attribuita alle abilità di comprensione e di produzione scritta (interpretazione e ... linguistica è probabilmente utilizzato per la prima volta nella seconda metà dell'Ottocento dal filologo Francesco d'Ovidio (Lo Duca 2003); con certezza è introdotto agli inizi del Novecento dal pedagogista Giuseppe ...doi:10.30687/978-88-6969-464-6/004 fatcat:keomohf5wvdhhgupahstipktje
The first is that of Annibale de Piero, a chemist (MF, pp. 404-407), and the second that of Felice Spingola, die mayor of Verbicaro, in Cosenza, die soudiern region from which many o f die brides came ... Giuseppe, a socialist, described the frustrations facing the few who did stand in elections: 'Con pochi y compagni ho fondato la sezione socialista. ...doi:10.5525/gla.thesis.70963 fatcat:bpajr233m5frldejd4ascchw34