2,963 research outputs found

    Optimal representation of our knowledge about seismic sources for PSHA in low deformation areas

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    characterization of the seismic sources, the definition of the attenuation law and the computation of the probabilistic seismic hazard. Our work is focus on the first two steps. Given that most active faults are not characterized well enough, in low deformation areas, seismic sources are generally defined as areal zones, delimited with finite boundary polygons, within which the geological features of active tectonics and the seismicity are deemed homogeneous. Besides the lack of data (e.g., narrow range of recorded magnitudes), the application of this representation generates different problems: 1) a large sensitivity of resulting hazard maps on the location of zone boundaries, while these boundaries are set by expert decision; 2) the zoning can not represent any variation in faulting mechanism; 3) the seismicity rates are distributed throughout the zones and we lose the location of the determinant information used for their calculation. We propose an exploratory study for an alternative procedure in area source modeling. This method allows to obtain a limit, and its uncertainties, between two zones, separated by two different seismic activity rates. Since we obtain this limit, we can recover the seismic activity rates for both zones.The important features for this developed method is the location and magnitude of the largest earthquakes. Given than the largest events are not recorded by instruments,we decide to use the Bakun and Wentworth method (1997) to better characterize the epicentral region and the magnitude of the instrumental earthquakes. Because of the unusual shape of the isoseismal lines of the 1909 Benavente event, we decided to apply this methodology to this event. The result show that the estimated epicenter (Kárnik, 1969) is within all the confidence-level. Because of the low magnitude estimation, we decide to test the sensibility of this method to the attenuation law. A new law is developed using a compilation of macroseismic reports and will be used to re-estimate the epicentral region and the magnitude of the 1909 Benavente event.The logarithmic trends of intensities with the median distance suggests a logarithmic form for the attenuation law. Then, this law will be used to re-evaluate the estimations of both epicentral region and magnitude of the 1909 Benavente event

    From Design to Production Control Through the Integration of Engineering Data Management and Workflow Management Systems

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    At a time when many companies are under pressure to reduce "times-to-market" the management of product information from the early stages of design through assembly to manufacture and production has become increasingly important. Similarly in the construction of high energy physics devices the collection of (often evolving) engineering data is central to the subsequent physics analysis. Traditionally in industry design engineers have employed Engineering Data Management Systems (also called Product Data Management Systems) to coordinate and control access to documented versions of product designs. However, these systems provide control only at the collaborative design level and are seldom used beyond design. Workflow management systems, on the other hand, are employed in industry to coordinate and support the more complex and repeatable work processes of the production environment. Commercial workflow products cannot support the highly dynamic activities found both in the design stages of product development and in rapidly evolving workflow definitions. The integration of Product Data Management with Workflow Management can provide support for product development from initial CAD/CAM collaborative design through to the support and optimisation of production workflow activities. This paper investigates this integration and proposes a philosophy for the support of product data throughout the full development and production lifecycle and demonstrates its usefulness in the construction of CMS detectors.Comment: 18 pages, 13 figure

    Design Patterns for Description-Driven Systems

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    In data modelling, product information has most often been handled separately from process information. The integration of product and process models in a unified data model could provide the means by which information could be shared across an enterprise throughout the system lifecycle from design through to production. Recently attempts have been made to integrate these two separate views of systems through identifying common data models. This paper relates description-driven systems to multi-layer architectures and reveals where existing design patterns facilitate the integration of product and process models and where patterns are missing or where existing patterns require enrichment for this integration. It reports on the construction of a so-called description-driven system which integrates Product Data Management (PDM) and Workflow Management (WfM) data models through a common meta-model.Comment: 14 pages, 13 figures. Presented at the 3rd Enterprise Distributed Object Computing EDOC'99 conference. Mannheim, Germany. September 199

    The Reification of Patterns in the Design of Description-Driven Systems

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    To address the issues of reusability and evolvability in designing self- describing systems, this paper proposes a pattern-based, object-oriented, description-driven system architecture. The proposed architecture embodies four pillars - first, the adoption of a multi-layered meta-modeling architecture and reflective meta-level architecture, second, the identification of four data modeling relationships that must be made explicit such that they can be examined and modified dynamically, third, the identification of five design patterns which have emerged from practice and have proved essential in providing reusable building blocks for data management, and fourth, the encoding of the structural properties of the five design patterns by means of one pattern, the Graph pattern. The CRISTAL research project served as the basis onto which the pattern-based meta-object approach has been applied. The proposed architecture allows the realization of reusability and adaptability, and is fundamental in the specification of self-describing data management components.Comment: 10 pages 11 figure

    Meta-Data Objects as the Basis for System Evolution

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    One of the main factors driving object-oriented software development in the Web- age is the need for systems to evolve as user requirements change. A crucial factor in the creation of adaptable systems dealing with changing requirements is the suitability of the underlying technology in allowing the evolution of the system. A reflective system utilizes an open architecture where implicit system aspects are reified to become explicit first-class (meta-data) objects. These implicit system aspects are often fundamental structures which are inaccessible and immutable, and their reification as meta-data objects can serve as the basis for changes and extensions to the system, making it self- describing. To address the evolvability issue, this paper proposes a reflective architecture based on two orthogonal abstractions - model abstraction and information abstraction. In this architecture the modeling abstractions allow for the separation of the description meta-data from the system aspects they represent so that they can be managed and versioned independently, asynchronously and explicitly. A practical example of this philosophy, the CRISTAL project, is used to demonstrate the use of meta-data objects to handle system evolution
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