73 research outputs found
Automated Synthesis: a Distributed Viewpoint
Distributed algorithms are inherently hard to get right, and a major challenge is to come up with automated techniques for error detection and recovery. The talk will survey recent results on the synthesis of distributed monitors and controllers
Polynomial Synthesis of Asynchronous Automata
Zielonka's theorem shows that each regular set of Mazurkiewicz traces can be
implemented as a system of synchronized processes with a distributed control
structure called asynchronous automaton. This paper gives a polynomial
algorithm for the synthesis of a non-deterministic asynchronous automaton from
a regular Mazurkiewicz trace language. This new construction is based on an
unfolding approach that improves the complexity of Zielonka's and Pighizzini's
techniques in terms of the number of states.Comment: The MOdelling and VErification (MOVE) tea
A Nice Labelling for Tree-Like Event Structures of Degree 3 (Extended Version)
We address the problem of finding nice labellings for event structures of
degree 3. We develop a minimum theory by which we prove that the labelling
number of an event structure of degree 3 is bounded by a linear function of the
height. The main theorem we present in this paper states that event structures
of degree 3 whose causality order is a tree have a nice labelling with 3
colors. Finally, we exemplify how to use this theorem to construct upper bounds
for the labelling number of other event structures of degree 3
A regular viewpoint on processes and algebra
While different algebraic structures have been proposed for the treatment of concurrency, finding solutions for equations over these structures needs to be worked on further. This article is a survey of process algebra from a very narrow viewpoint, that of finite automata and regular languages. What have automata theorists learnt from process algebra about finite state concurrency? The title is stolen from [31]. There is a recent survey article [7] on finite state processes which deals extensively with rational expressions. The aim of the present article is different. How do standard notions such as Petri nets, Mazurkiewicz trace languages and Zielonka automata fare in the world of process algebra? This article has no original results, and the attempt is to raise questions rather than answer them
Asynchronous Games over Tree Architectures
We consider the task of controlling in a distributed way a Zielonka
asynchronous automaton. Every process of a controller has access to its causal
past to determine the next set of actions it proposes to play. An action can be
played only if every process controlling this action proposes to play it. We
consider reachability objectives: every process should reach its set of final
states. We show that this control problem is decidable for tree architectures,
where every process can communicate with its parent, its children, and with the
environment. The complexity of our algorithm is l-fold exponential with l being
the height of the tree representing the architecture. We show that this is
unavoidable by showing that even for three processes the problem is
EXPTIME-complete, and that it is non-elementary in general
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