Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Fundamenta Informaticae

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: occurrence nets

Sortuj według:

Ogranicz wyniki do:

Building Occurrence Nets from Reveals Relations

Balaguer S., Chatain T., Haar S.

Fundamenta Informaticae

2013

Vol. 123, nr 3

245--272

Occurrence nets are a well known partial order model for the concurrent behavior of Petri nets. The causality and conflict relations between events, which are explicitly represented in occurrence nets, induce logical dependencies between event occurrences: the occurrence of an event e in a run implies that all its causal predecessors also occur, and that no event in conflict with e occurs. But these structural relations do not express all the logical dependencies between event occurrences in maximal runs: in particular, the occurrence of e in any maximal run may imply the occurrence of another event that is not a causal predecessor of e, in that run. The reveals relation has been introduced to express this dependency between two events. Here we generalize the reveals relation to express more general dependencies, involving more than two events, and we introduce ERL logic to express them as boolean formulas. Finally we answer the synthesis problem that arises : given an ERL formula φ, is there an occurrence net N such that φ describes exactly the dependencies between the events of N?

Structured Occurrence Nets: A Formalism for Aiding System Failure Prevention and Analysis Techniques

Koutny M., Randell B.

Fundamenta Informaticae

2009

Vol. 97, nr 1/2

41-91

This paper introduces the concept of a "structured occurrence net", which as its name indicates is based on that of an "occurrence net", a well-established formalism for an abstract record that represents causality and concurrency information concerning a single execution of a system. Structured occurrence nets consist of multiple occurrence nets, associated together by means of various types of relationship, and are intended for recording or predicting, either the actual behaviour of complex systems as they communicate and evolve, or evidence that is being gathered and analysed concerning their alleged past behaviour. We provide a formal basis for the new formalism and show how it can be used to gain better understanding of complex fault-error-failure chains (i) among co-existing communicating systems, (ii) between systems and their sub-systems, and (iii) involving systems that are controlling, creating ormodifying other systems. We then go on to discuss how, with appropriate tools support, perhaps using extended versions of existing tools, structured occurrence nets could form a basis for improved techniques of system failure prevention and analysis.