The ambient calculus is a calculus of computation that allows active processes to communicate and to move between sites. A site is said to be a protective firewall whenever it denies entry to all attackers not possessing the required passwords. We devise a computationally sound test for validating the protectiveness of a proposed firewall and show how to perform the test in polynomial time. The...

This paper presents a comparison between two unsupervised neural network models: (i) the well-known Fuzzy ART, and (ii) AUTOWISARD, a new unsupervised version of the classic WISARD weightless neural network model. It is shown that AUTOWISARD is simple, fast and stable, whilst keeping compatibility with the original WISARD architecture. Experimental test results over binary patterns benchmarks h...

Do we always use the same name for the same concept? Usually not. While misunderstandings are always troublesome, they pose particularly critical problems in software projects. Requirements engineering deals intensively with reducing the number and scope of misunderstandings between software engineers and customers. Software maintenance is another important task where proper understanding of th...

When using a model to predict the behavior of a physical system of interest, engineers must be confident that, under the conditions of interest, the model is an adequate representation of the system. The process of building this confidence is called model validation. It requires that engineers have knowledge about the system and conditions of interest, properties of the model and their own tole...

A currency area can be a self-validating optimal policy regime, even when monetary unification does not foster real economic integration and intra-industry trade. In our model firms choose the degree of exchange rate pass-through onto export prices accounting for expected monetary policies, and monetary authorities choose optimal policy rules taking firms’ pass-through as given. We show that th...

Following the translation validation approach to highassurance compilation, we describe a new algorithm for validating a posteriori the results of a run of register allocation. The algorithm is based on backward dataflow inference of equations between variables, registers and stack locations, and can cope with sophisticated forms of spilling and live range splitting, as well as many forms of ar...

Semistructured data has become prevalent in both web applications and database systems. This rapid growth in use makes the design of good semistructured data essential. Formal semantics and automated reasoning tools enable us to reveal the inconsistencies in a semistructured data model and its instances. The Object Relationship Attribute model for Semistructured data (ORASS) is a graphical nota...

A critical element in the use of PDDL2.1, the modelling language developed for the International Planning Competition series, has been the common understanding of the semantics of the language. The fact that this has been implemented in plan validation software was vital to the progress of the competition. However, the validation of plans using actions with continuous effects presents new chall...

A crucial task in process management is the validation of process refinements. A process refinement is a process description in a more fine-grained representation. The refinement is with respect to either an abstract model or a component’s principle behaviour model. We define process refinement based on the execution set semantics. Predecessor and successor relations of the activities are descr...