Thomas Leonard

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Network latency is a problem for all cloud services. It can be mitigated by moving computation out of remote datacenters by rapidly instantiating local services near the user. This requires an embedded cloud platform on which to deploy multiple applications securely and quickly. We present Jitsu, a new Xen tool-stack that satisfies the demands of secure(More)
Although different web sites structure their pages differently, the pages within a single site are often generated from a database and have a regular layout from which it is possible to extract information automatically. Dome is a visual tool for manipulating tree-structured documents. It can import and export in XML or HTML formats, making it ideal for(More)
Grids are becoming economically viable and productive tools. They provide a way of utilizing a vast array of linked resources such as computing systems, databases and services online within Virtual Organizations (VO). However, today's Grid architectures are not capable of supporting dynamic, agile federation across multiple administrative domains and the(More)
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(More)
Access control is a critical feature of many systems, including networks of services, processes within a computer, and objects within a running process. The security consequences of a particular architecture or access control policy are often difficult to determine, especially where some components are not under our control, where components are created(More)
In grids, delegation is a key facility that can be used to authenticate and authorize requests on behalf of disconnected users. In current grid systems, delegation is either performed dynamically, in an unrestricted manner, or by a secure but static method. Unfortunately, the former compromises security and the latter cannot satisfy the requirements of(More)
Two nested or non-nested candidate sampling models for an observed data set may be compared by consideration of summaries of a probability plot, which contrasts the posterior quantiles of the log-likelihoods under the two models. The procedures address both preference inference and refutation inference, and extensions to DIC and alternatives to AIC are(More)
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