Authenticity and Provenance in Long Term Digital Preservation: Modeling and Implementation in Preservation Aware Storage

none1http://www.usenix.org/event/tapp09/tech/full_papers/factor/factor.pdf - ISSN:openGUERCIO M.Guercio, Mari

A provenance metadata model integrating ISO geospatial lineage and the OGC WPS : conceptual model and implementation

Nowadays, there are still some gaps in the description of provenance metadata. These gaps prevent the capture of comprehensive provenance, useful for reuse and reproducibility. In addition, the lack of automated tools for capturing provenance hinders the broad generation and compilation of provenance information. This work presents a provenance engine (PE) that captures and represents provenance information using a combination of the Web Processing Service (WPS) standard and the ISO 19115 geospatial lineage model. The PE, developed within the MiraMon GIS & RS software, automatically records detailed information about sources and processes. The PE also includes a metadata editor that shows a graphical representation of the provenance and allows users to complement provenance information by adding missing processes or deleting redundant process steps or sources, thus building a consistent geospatial workflow. One use case is presented to demonstrate the usefulness and effectiveness of the PE: the generation of a radiometric pseudo-invariant areas bench for the Iberian Peninsula. This remote-sensing use case shows how provenance can be automatically captured, also in a non-sequential complex flow, and its essential role in the automation and replication tasks in work with very large amounts of geospatial data

Robust Workflows for Large-Scale Multiphysics Simulation

International audienceLarge-scale simulations, e.g. fluid-structure interactions and aeroacoustics noise generation, require important computing power, visualization systems and high-end storage capacity. Because 3D multi-physics simulations also run long processes on large datasets, an important issue is the robustness of the computing systems involved, i.e., the ability to resume the inadvertantly aborted computations. A new approach is presented here to handle application failures. It is based on extensions of bracketing checkpoints usually implemented in database and transactional systems. An assymetric scheme is devised to reduce the number of checkpoints required to safely restart aborted applications when unexpected failures occur. The tasks are controled by a workflow graph than can be deployed on various distributed platforms and high-performance infrastructures. An automated bracketing process inserts in the workflow graph checkpoints that are placed at critical execution points in the graph. The checkpoints are inserted using a heuristic process based on a evolving set of rules. Preliminary tests show that the number of checkpoints, hence the overhead incurred by the checkpointing mechanism, can be significantly reduced to enhance the application performance while supporting its resilience

Scientific Workflows: Past, Present and Future

International audienceThis special issue and our editorial celebrate 10 years of progress with data-intensive or scientific workflows. There have been very substantial advances in the representation of workflows and in the engineering of workflow management systems (WMS). The creation and refinement stages are now well supported, with a significant improvement in usability. Improved abstraction supports cross-fertilisation between different workflow communities and consistent interpretation as WMS evolve. Through such re-engineering the WMS deliver much improved performance, significantly increased scale and sophisticated reliability mechanisms. Further improvement is anticipated from substantial advances in optimisation. We invited papers from those who have delivered these advances and selected 14 to represent today's achievements and representative plans for future progress. This editorial introduces those contributions with an overview and categorisation of the papers. Furthermore, it elucidates responses from a survey of major workflow systems, which provides evidence of substantial progress and a structured index of related papers. We conclude with suggestions on areas where further research and development is needed and offer a vision of future research directions