Order-based element labeling for tree-structured XML data is an important technique in XML
processing. It lies at the core of many fundamental XML operations such as containment join …

Circus combines constructs to define complex data operations and interactions; it integrates
Z and CSP, and, distinctively, it is a language for refinement that can describe programs as …

This paper reports on the Xenon project's use of formal methods. Xenon is a higher-
assurance secure hypervisor based on re-engineering the Xen open-source hypervisor. The …

Context: The demand from industry for more dependable and scalable test-development
mechanisms has fostered the use of formal models to guide the generation of tests. Despite …

Separation kernels are the strongest known form of separation for virtual machines. We
agree with NSA's Information Assurance Directorate that while separation kernels are …

The up-front choice of security policy and formalism used to model it is critical to the success
of projects that seek to enforce information-flow security. This paper reports on the Xenon …

Since state-rich formalism is a combination of Z, CSP, refinement calculus and Dijkstra's
guarded commands, its model checking is intrinsically more complicated and difficult than …

Abstract The Unifying Theories of Programming underpins the development of Circus, a
state-rich process algebra for refinement. We have previously presented a theory of testing …

The work presented in this thesis is a contribution to formal specification and verification
methods. Formal specifications are used to describe a software, or more generally a system …

Circus is a concurrent language tailored for refinement that combines Z, CSP, and the
refinement calculus using Hoare and He's Unifying Theories of Programming (UTP). In this …