Model-Based Synthesis of Incremental and Correct Estimators for Discrete Event Systems

State tracking, i.e. estimating the state over time, is always an important problem in autonomous dynamic systems. Run-time requirements advocate for incremental estimation and memory limitations lead us to consider an estimation strategy that retains only one state out of the set of candidate estimates at each time step. This avoids the ambiguity of a high number of candidate estimates and allows the decision system to be fed with a clear input. However, this strategy may lead to dead-ends in the continuation of the execution. In this paper, we show that single-state trackability can be expressed in terms of the simulation relation between automata. This allows us to provide a complexity bound and a way to build estimators endowed with this property and, moreover, customizable along some correctness criteria. Our implementation relies on the Sat Modulo Theory solver MonoSAT and experiments show that our encoding scales up and applies to real world scenarios.

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Failure diagnosis of dynamic systems: an approach based on discrete event systems

Proceedings of the 2001 American Control Conference. (Cat. No.01CH37148) ◽

10.1109/acc.2001.946047 ◽

2001 ◽

Cited By ~ 47

Author(s):

S. Lafortune ◽

D. Teneketzis ◽

M. Sampath ◽

R. Sengupta ◽

K. Sinnamohideen

Keyword(s):

Dynamic Systems ◽

Discrete Event Systems ◽

Discrete Event ◽

Failure Diagnosis ◽

Event Systems

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Fault Diagnosis for Discrete Event Systems Using Partially Observed Petri Nets

Mathematical Problems in Engineering ◽

10.1155/2020/2392904 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

Ye Dandan ◽

Luo Jiliang ◽

Su Hongye

Keyword(s):

Fault Diagnosis ◽

Petri Net ◽

Discrete Event Systems ◽

Discrete Event ◽

Diagnostic Process ◽

Structure Information ◽

Event Systems ◽

Time Requirements ◽

Diagnosis Method ◽

Partially Observable

This study proposes a fault diagnosis method of discrete event systems on the basis of a Petri net model with partially observable transitions. Assume that the structure of the Petri net model and the initial marking are known, and the faults can be modeled by its unobservable transitions. One of the contributions of this work is the use of the structure information of Petri net to construct an online fault diagnoser which can describe the system behavior of normal or potential faults. By modeling the flow of tokens in particular places that contain fault information, the variation of tokens in these places may be calculated. The outputs and inputs of these places are determined to be enabled or not through analyzing some special structures. With the structure information, traversing all the states is not required. Furthermore, the computational complexity of the polynomial allows the model to meet real-time requirements. Another contribution of this work is to simplify the subnet model ahead of conducting the diagnostic process with the use of reduction rules. By removing some nodes that do not contain the necessary diagnostic information, the memory cost can be reduced.

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Hybrid adaptive Petri nets: a conceptual framework for partial fluidization of Petri nets

Jornada de Jóvenes Investigadores del I3A ◽

10.26754/jji-i3a.201201888 ◽

1970 ◽

pp. 50

Author(s):

E. Fraca ◽

J. Júlvez ◽

M. Silva

Keyword(s):

Petri Nets ◽

Petri Net ◽

Dynamic Systems ◽

Discrete Event Systems ◽

Discrete Event ◽

Modeling And Analysis ◽

Analysis Techniques ◽

High Transition ◽

Large Systems ◽

Event Dynamic

Petri nets (PNs) constitute a well known family of formalisms for the modeling and analysis ofDiscrete Event Dynamic Systems (DEDS). As most formalisms for discrete event systems, PNssuffer from the state explosion problem, which renders enumerative analysis techniquesunfeasible for large systems. A technique to overcome the problem is to relax integralitycontraints of the discrete PN model, leading to continuous PN. This relaxation highly reducesthe complexity of analysis techniques but may not preserve important properties of theoriginal PN system such as deadlock‐freeness, liveness, reversibility, etc. This work focuses onHybrid Adaptive Petri nets (HAPNs), a Petri net based formalism in which the firing oftransitions is partially relaxed. The transitions of a HAPN can behave in two different modes:continuous mode for high transition workload, and discrete in other case. This way, a HAPN isable to adapt its behaviour to the net workload, it offers the possibility to represent morefaithfully the discrete model and use efficient analysis techniques by behaving as continuouswhen the load is high. Reachability space and the deadlock‐freeness property of hybridadaptive nets is studied in this work.

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