Cross-middleware Interoperability in Distributed Concurrent Engineering

Secure, distributed collaboration between different organizations is a key challenge in Grid computing today. The GDCD project has produced a Grid-based demonstrator Virtual Collaborative Facility (VCF) for the European Space Agency. The purpose of this work is to show the potential of Grid technology to support fully distributed concurrent design, while addressing practical considerations including network security, interoperability, and integration of legacy applications. The VCF allows domain engineers to use the concurrent design methodology in a distributed fashion to perform studies for future space missions. To demonstrate the interoperability and integration capabilities of Grid computing in concurrent design, we developed prototype VCF components based on ESA’s current Excel-based Concurrent Design Facility (a non-distributed environment), using a STEP-compliant database that stores design parameters. The database was exposed as a secure GRIA 5.1 Grid service, whilst a .NET/WSE3.0-based library was developed to enable secure communication between the Excel client and STEP database

Design of distributed database

Issued as Final report, Project no. G-36-66

Rigorous Design of Fault-Tolerant Transactions for Replicated Database Systems using Event B

System availability is improved by the replication of data objects in a distributed database system. However, during updates, the complexity of keeping replicas identical arises due to failures of sites and race conditions among conflicting transactions. Fault tolerance and reliability are key issues to be addressed in the design and architecture of these systems. Event B is a formal technique which provides a framework for developing mathematical models of distributed systems by rigorous description of the problem, gradually introducing solutions in refinement steps, and verification of solutions by discharge of proof obligations. In this paper, we present a formal development of a distributed system using Event B that ensures atomic commitment of distributed transactions consisting of communicating transaction components at participating sites. This formal approach carries the development of the system from an initial abstract specification of transactional updates on a one copy database to a detailed design containing replicated databases in refinement. Through refinement we verify that the design of the replicated database confirms to the one copy database abstraction

Ownership principles for distributed database design

Includes bibliographical references.Marshall Van Alstyne, Erik Brynjolfsson, Stuart E. Madnick

The Design of a Distributed Database for Doctoral Studies Management

This paper aims to create a system that manages doctoral school requirements. The management of doctoral school implies administration of information like PhD personal information, Supervisors, Teachers, and other information that may be useful. We will debate on distributed database term as the proposed database project will have the same structure for four universities. Each university will be able to work on this database by accessing its own set of data and properly using the information received. This project will track the creation of a database to manage all the information needed and provide answers using these data.Distributed Database, Fragmentation, Top-Down Design Process

Distributed Database Design: A Case Study

Data Allocation is an important problem in Distributed Database Design. Generally, evolutionary algorithms are used to determine the assignments of fragments to sites. Data Allocation Algorithms should handle replication, query frequencies, quality of service (QoS), cite capacities, table update costs, selection and projection costs. Most of the algorithms in the literature attack one or few components of the problem. In this paper, we present a case study considering all of these features. The proposed model uses Integer Linear Programming for the formulation of the problem. (C) 2014 The Authors. Published by Elsevier B.V

Distributed computational fluid dynamics

Computational fluid dynamics simulations of relevance to jet-engine design, for instance, are extremely computationally demanding and the use of large-scale distributed computing will allow the solution of problems that cannot be tackled using current resources. It is often appropriate to leave the large datasets generated by CFD codes local to the compute resource in use at the time. This naturally leads to a distributed database of results that will need to be federated as a coherent resource for the engineering community. We describe the use of Globus and Condor within Cambridge for sharing computer resources, progress on defining XML standards for the annotation of CFD datasets and a distributed database framework for them