Bernard Butler

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Software packages have made sequence analysis easier and more accessible to research scientists in many fields. The majority of these packages are routinely upgraded to include improved and innovative programs for primer design, sequence assembly and improvements in database searching programs. The interfaces of many packages have also been improved,(More)
We study the problem of optimising the provisioning of collections of virtual machines (VMs) having different placement constraints (e.g., security and anti-collocation) and characteristics (e.g., memory and disk capacity), given a set of physical machines (PMs) with known specifications, in order to achieve the objective of maximising an IaaS cloud(More)
There is growing awareness of the need to protect digital resources and services in both corporate and home ICT scenarios. Meanwhile, communication tools tailored for corporations are blurring the line between communication mechanisms and (near) real-time resource sharing. The resulting requirement for near real-time policy-based access control is(More)
The performance and scalability of access control systems is growing more important as organisations deploy ever more complex communications and content management systems. Fine-grained access control is becoming more pervasive, so decisions are more frequent and policy sets are larger. We outline a flexible performance testing framework that accepts XACML(More)
The performance and scalability of access control systems is a growing concern as organisations deploy ever more complex communications and content management systems. This paper describes how an (offline) experimental testbed may be used to address performance concerns. To begin, timing measurements are collected from a server component incorporating the(More)
Resource access control policies for an organization are often derived from best practice standards or from high level business policies. To ensure that access control is enforced effectively, these business policies need to be translated into deployable system configurations or lower level policies for multiple diverse systems. These target policy(More)