217 research outputs found
Towards a Theory of Glue
We propose and study the notions of behaviour type and composition operator
making a first step towards the definition of a formal framework for studying
behaviour composition in a setting sufficiently general to provide insight into
how the component-based systems should be modelled and compared. We illustrate
the proposed notions on classical examples (Traces, Labelled Transition Systems
and Coalgebras). Finally, the definition of memoryless glue operators, takes us
one step closer to a formal understanding of the separation of concerns
principle stipulating that computational aspects of a system should be
localised within its atomic components, whereas coordination layer responsible
for managing concurrency should be realised by memoryless glue operators.Comment: In Proceedings ICE 2012, arXiv:1212.345
Interface Simulation Distances
The classical (boolean) notion of refinement for behavioral interfaces of
system components is the alternating refinement preorder. In this paper, we
define a distance for interfaces, called interface simulation distance. It
makes the alternating refinement preorder quantitative by, intuitively,
tolerating errors (while counting them) in the alternating simulation game. We
show that the interface simulation distance satisfies the triangle inequality,
that the distance between two interfaces does not increase under parallel
composition with a third interface, and that the distance between two
interfaces can be bounded from above and below by distances between
abstractions of the two interfaces. We illustrate the framework, and the
properties of the distances under composition of interfaces, with two case
studies.Comment: In Proceedings GandALF 2012, arXiv:1210.202
Expressiveness and Completeness in Abstraction
We study two notions of expressiveness, which have appeared in abstraction
theory for model checking, and find them incomparable in general. In
particular, we show that according to the most widely used notion, the class of
Kripke Modal Transition Systems is strictly less expressive than the class of
Generalised Kripke Modal Transition Systems (a generalised variant of Kripke
Modal Transition Systems equipped with hypertransitions). Furthermore, we
investigate the ability of an abstraction framework to prove a formula with a
finite abstract model, a property known as completeness. We address the issue
of completeness from a general perspective: the way it depends on certain
abstraction parameters, as well as its relationship with expressiveness.Comment: In Proceedings EXPRESS/SOS 2012, arXiv:1208.244
Simulation and Bisimulation over Multiple Time Scales in a Behavioral Setting
This paper introduces a new behavioral system model with distinct external
and internal signals possibly evolving on different time scales. This allows to
capture abstraction processes or signal aggregation in the context of control
and verification of large scale systems. For this new system model different
notions of simulation and bisimulation are derived, ensuring that they are,
respectively, preorders and equivalence relations for the system class under
consideration. These relations can capture a wide selection of similarity
notions available in the literature. This paper therefore provides a suitable
framework for their comparisonComment: Submitted to 22nd Mediterranean Conference on Control and Automatio
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