169,841 research outputs found
Future Parallel Computers: An Advanced Course, Pisa, Italy, June 9-20, 1986, Proceedings
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Modellazione stocastica della fratturazione (Metodo Discrete Fracture Network) a supporto della stima previsionale di resa all’interno di bacini estrattivi di pietre ornamentali
No full textThe present paper shows a working approach aimed at improving quarry yield prediction accuracy in ornamental stone basins. In such contest, the yield prediction is subjected toa degree of uncertainty due to several factors, as the fracture network, the geomechanical properties of the rock and other qualitative characteristics of the ornamental stones. To decrease such uncertainty, we proposed an approach based on the Discrete Fracture Network (DFN) technique. The DFN is a stochastic approach for reproducing the discontinuity pattern starting from deterministic measurements of different parameters acquired during field surveys, as for example fracture intensity and density. A specific algorithm creates a fracture network compatible from a statistic point of view with the data collected on the quarry rock faces, overcoming the limitations of a purely deterministic approach. This study used the DFN methodology in a marble quarry (Apuan Alps, Italy), where it has been possible to increase the reliability of the quarry yield prediction in terms of dimension of extractable intact blocks, which is the starting point of a series of other qualitative considerations
Fracture mapping in challenging environment: a 3D virtual reality approach combining terrestrial LiDAR and high definition images
No full textArticleThis is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this record.The latest technological developments in computer vision allow the creation of georeferenced, non-immersive desktop virtual reality (VR) environments. VR uses a computer to produce a simulated three-dimensional world in which it is possible to interact with objects and derive metric and thematic data. In this context, modern geomatic tools enable the remote acquisition of information that can be used to produce georeferenced high-definition 3D models: these can be used to create a VR in support of rock mass data processing, analysis, and interpretation. Data from laser scanning and high quality images were combined to map deterministically and characterise discontinuities with the aim of creating accurate rock mass models. Discontinuities were compared with data from traditional engineering-geological surveys in order to check the level of accuracy in terms of the attitude of individual joints and sets. The quality of data collected through geomatic surveys and field measurements in two marble quarries of the Apuan Alps (Italy) was very satisfactory. Some fundamental geotechnical indices (e.g. joint roughness, alteration, opening, moisture, and infill) were also included in the VR models. Data were grouped, analysed, and shared in a single repository for VR visualization and stability analysis in order to study the interaction between geology and human activities.The authors gratefully acknowledge the assistance of the personal of the Romana Quarry and particularly Corniani M. This paper was possible because of support from the Tuscany Region Research Project known as “Health and safety in the quarries of ornamental stones—SECURECAVE”. The authors acknowledge Pellegri M and Gullì D (Local Sanitary Agency n.1, Mining Engineering Operative Unit—Department of Prevention) and Riccucci S (Centre of GeoTechnologies, University of Siena) for their support of this research
Assessment of a Rock Pillar Failure by Using Change Detection Analysis and FEM Modelling
No full textIn this paper, various methods have been used to control and evaluate engineering difficulties in mining accurately. Different unstable scenarios occurring at the surfaces of underground mine walls, have been identified by comparing 3D terrestrial laser scanning surveys and subsequent point cloud 3D analysis. These techniques, combined with a change detection analysis approach and the integration of rock mechanics’ modelling, represent an asset for the assessment and management of the risk in mining. The change detection analysis can be used as control of mining and industrial processes as well as to identify valid model scenarios for establishing possible failure
causes. A pillar spalling failure has been identified in an Italian underground marble quarry and this topic represents the basis of the present paper. A Finite-Element Method was used to verify the occurrence of relatively high-stress concentrations in the pillar. The FEM modelling revealed that stresses in the proximity of the pillar may have sufficient magnitude to induce cracks growth and spalling failure
Fault tolerance for data parallel programs
No full textThe main issues when supporting fault tolerance based on checkpointing and rollback recovery for
High-Performance applications are related to the scalability of the introduced support, the possibility of
analyzing the induced overhead and, in more general terms, the optimization of the trade-off between
failure-free and recovery performances. In this paper we describe our contribution in fault tolerance for
high-level structured parallelism models. We take a different viewpoint w.r.t. existing contributions, by
introducing a methodology to derive interesting properties to support fault tolerance. We show how to
apply this methodology to a general data parallel model, deriving useful properties to introduce a class
of checkpointing protocols. Thanks to this methodology, this class of protocols is not affected by the
described issues. We exemplify two checkpointing protocols and the related rollback recovery techniques.
For each protocol we also derive cost models statically describing the failure-free performance, which can
be used for performance tuning or to target some Quality of Service parameter. To assess the innovation
of the results we analytically and experimentally compare the introduced protocols with two literature
protocols. Results show that while the protocols introduced in this paper permit the definition of cost
models and have a good scalability, the literature protocols do not always have these properties
Grid Technologies and c-Business for SMEs
No full textWe describe the objectives of project SFIDA, aiming at developing a Grid-based interoperable platform able to support next generation applications specifically addressing the needs of SMEs. We sketch the architecture of the platform under development in SFIDA, which will support componentization (eservices) , intelligence (mining), collaboration (c-business), and customer businessprocesses orientation concepts on top of ASSIST, a Grid-aware high-level programming environment. The SFIDA project outcomes will be validated on Supply Chain Management applications matching various typical industrial cases, spanning from automotive, textile, food, white goods, and media retail. Finally we show what business benefits it is expected to bring
A Performance Model for Stream-Based Computations
No full textComponent-based Grid applications have complex deployment models. Performance-sensitive decisions should be taken by automatic tools. Such tools must match developer knowledge on component performance with QoS requirements on the applications, in order to find deployment plans that satisfy a Service Level Agreement (SLA). This paper presents a steady state performance model that can be employed to reason about and automatically map stream-based component programs
ASSIST as a research framework for high-performance grid programming environments
No full textASSIST (A Software development System based upon Integrated Skeleton
Technology) is a programming environment oriented to the development of parallel
and distributed high-performance applications according to a unified approach. The
language and implementation features of ASSIST are a result of our long-term
research in parallel programming models and tools. ASSIST is evolving towards
programming environments for high-performance complex enabling platforms,
especially Grids. In this paper, we show how ASSIST can act as a valid research
vehicle to study, experiment and realize Grid-aware programming environments for
high-performance applications. Special emphasis is put on the innovative
methodologies, strategies and tools for dynamically adaptive applications, that
represent the necessary step for the success of Grid platforms.
First we discuss the conceptual framework for Grid-aware programming
environments, based upon structured parallel programming and components
technology, anticipating how ASSIST possesses the essential features required by
such framework. Then we summarize the ASSIST programming model, showing its
evolution, along the line of structured parallel programming, to solve critical
problems of expressive power, flexibility, interoperability and efficiency; some
examples, both of kernels and of complex applications, are used to point out the
ASSIST features. The modular compiler model and the current implementation for
heterogeneous platforms and Globus-based Grids are illustrated. We show the
features that allow ASSIST programs to be used in CORBA infrastructures, that
represents our basic starting point towards interoperability in Grid applications.
Finally, the presentation of all the previous issues is used to derive an ASSIST-based
model for supporting dynamically adaptive applications
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