Laura Bright

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There is an increase in the number of data sources that can be queried across the WWW. Such sources typically support HTML forms-based interfaces and search engines query collections of suitably indexed data. The data is displayed via a browser. One drawback to these sources is that there is no standard programming interface suitable for applications to(More)
Wide area data delivery requires timely propagation of up-to-date information to thousands of clients over a wide area network. Applications include web caching, RSS source monitoring, and email access via a mobile network. Data sources vary widely in their update patterns and may experience different update rates at different times or unexpected changes to(More)
        (More)
We consider an architecture of mediators and wrappers for Internet accessible WebSources of limited query capability. Each call to a source is a WebSource Implementation (WSI) and it is associated with both a capability and (a possibly dynamic) cost. The multiplicity of WSIs with varying costs and capabilities increases the complexity of a traditional(More)
The rapid growth of the Internet and support for interoperability protocols has increased the number of Web accessible sources, WebSources. Current wrapper mediator architectures need to be extended with a Wrapper Cost Model (WCM) for WebSources that can estimate the response time (delays) to access sources as well as other relevant statistics. In this(More)
Large-scale scientific workflows can perform many computationally intensive tasks and generate large volumes of derived data products. These systems pose many challenges to both creating and managing data products, including efficiently executing tasks and tracking data product lineage and metadata. In this paper we describe our experiences implementing an(More)
A variety of emerging wide area applications challenge existing techniques for data delivery to users and applications accessing data from multiple autonomous servers. In this paper, we develop a framework for comparing pull based solutions and present dual optimization approaches. The first approach maximizes user utility while satisfying constraints on(More)
An important challenge to e ective data delivery in wide area environments is maintaining the data freshness of objects using solutions that can scale to a large number of clients without incurring signi cant server overhead. Policies for maintaining data freshness are traditionally either push-based or pull-based. Push-based policies involve pushing data(More)