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I. Willers

Publications and source records attributed to I. Willers.

7 recordsLinked to original sources
arXiv2007

Mobile Computing in Physics Analysis - An Indicator for eScience

This paper presents the design and implementation of a Grid-enabled physics analysis environment for handheld and other resource-limited computing devices as one example of the use of mobile devices in eScience. Handheld devices offer great potential because they provide ubiquitous access to data and round-the-clock connectivity over wireless links. Our solution aims to provide users of handheld devices the capability to launch heavy computational tasks on computational and data Grids, monitor the jobs status during execution, and retrieve results after job completion. Users carry their jobs on their handheld devices in the form of executables (and associated libraries). Users can transparently view the status of their jobs and get back their outputs without having to know where they are being executed. In this way, our system is able to act as a high-throughput computing environment where devices ranging from powerful desktop machines to small handhelds can employ the power of the Grid. The results shown in this paper are readily applicable to the wider eScience community.

cs.DC↗
arXiv2007

DIANA Scheduling Hierarchies for Optimizing Bulk Job Scheduling

The use of meta-schedulers for resource management in large-scale distributed systems often leads to a hierarchy of schedulers. In this paper, we discuss why existing meta-scheduling hierarchies are sometimes not sufficient for Grid systems due to their inability to re-organise jobs already scheduled locally. Such a job re-organisation is required to adapt to evolving loads which are common in heavily used Grid infrastructures. We propose a peer-to-peer scheduling model and evaluate it using case studies and mathematical modelling. We detail the DIANA (Data Intensive and Network Aware) scheduling algorithm and its queue management system for coping with the load distribution and for supporting bulk job scheduling. We demonstrate that such a system is beneficial for dynamic, distributed and self-organizing resource management and can assist in optimizing load or job distribution in complex Grid infrastructures.

cs.DC↗
arXiv2001

XML for Domain Viewpoints

Within research institutions like CERN (European Organization for Nuclear Research) there are often disparate databases (different in format, type and structure) that users need to access in a domain-specific manner. Users may want to access a simple unit of information without having to understand detail of the underlying schema or they may want to access the same information from several different sources. It is neither desirable nor feasible to require users to have knowledge of these schemas. Instead it would be advantageous if a user could query these sources using his or her own domain models and abstractions of the data. This paper describes the basis of an XML (eXtended Markup Language) framework that provides this functionality and is currently being developed at CERN. The goal of the first prototype was to explore the possibilities of XML for data integration and model management. It shows how XML can be used to integrate data sources. The framework is not only applicable to CERN data sources but other environments too.

physics.ins-det↗
arXiv2001

Object Serialization and Deserialization Using XML

Interoperability of potentially heterogeneous databases has been an ongoing research issue for a number of years in the database community. With the trend towards globalization of data location and data access and the consequent requirement for the coexistence of new data stores with legacy systems, the cooperation and data interchange between data repositories has become increasingly important. The emergence of the eXtensible Markup Language (XML) as a database independent representation for data offers a suitable mechanism for transporting data between repositories. This paper describes a research activity within a group at CERN (called CMS) towards identifying and implementing database serialization and deserialization methods that can be used to replicate or migrate objects across the network between CERN and worldwide centres using XML to serialize the contents of multiple objects resident in object-oriented databases.

physics.ins-det↗
arXiv1999

Design Patterns for Description-Driven Systems

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.

physics.ins-det↗
arXiv1999

Getting Physics Data From the CMS ECAL Construction Database

CMS ECAL physicists must be able to extract physics characteristics from the ECAL construction database for the calibration of sets of detector components. Other applications, such as geometry for simulation and physics event reconstruction, will also need to extract data from the construction database. In each case, application software needs to query the construction database and to extract data that satisfies a particular view. These viewpoints are defined for a specific purpose (e.g. simulation, slow control, calibration) and data must be extracted into the viewpoint for a set of defined detector components (e.g. readout channels) called physics elements. The ECAL construction database follows an object-oriented design to maximise flexibility and reusability. An meta-modelling approach has been taken in its design, which promotes self-description and a degree of data independence. A query facility is being provided to allow navigation around so-called meta-objects in the construction database, facilitating the extraction of physics data into a particular viewpoint. This paper outlines how viewpoints can be populated with data extracted from the construction database, for a set of detector elements relevant for analysis.

physics.ins-det↗