12,406 research outputs found
Petri net controlled grammars with a bounded number of additional places
A context-free grammar and its derivations can be described by a Petri net, called a context-free Petri net, whose places and transitions correspond to the nonterminals and the production rules of the grammar, respectively, and tokens are separate instances of the nonterminals in a sentential form. Therefore , the control of the derivations in a context-free grammar can be implemented by adding some features to the associated cf Petri net. The addition of new places and new arcs from/to these new places to/from transitions of the net leads grammars controlled by k-Petri nets, i.e., Petri nets with additional k places. In the paper we investigate the generative power and give closure properties of the families of languages generated by such Petri net controlled grammars, in particular, we show that these families form an infinite hierarchy with respect to the numbers of additional places
On Languages Accepted by P/T Systems Composed of joins
Recently, some studies linked the computational power of abstract computing
systems based on multiset rewriting to models of Petri nets and the computation
power of these nets to their topology. In turn, the computational power of
these abstract computing devices can be understood by just looking at their
topology, that is, information flow.
Here we continue this line of research introducing J languages and proving
that they can be accepted by place/transition systems whose underlying net is
composed only of joins. Moreover, we investigate how J languages relate to
other families of formal languages. In particular, we show that every J
language can be accepted by a log n space-bounded non-deterministic Turing
machine with a one-way read-only input. We also show that every J language has
a semilinear Parikh map and that J languages and context-free languages (CFLs)
are incomparable
State machine of place-labelled Petri net controlled grammars
A place-labelled Petri net controlled grammar is, in general, a context-free grammar equipped with a Petri net and a function which maps places of the net to productions of the grammar. The languages of place-labelled Petri net controlled grammar consist of all terminal strings that can be obtained by parallel application of the rules of multisets which are the images of the sets of input places in a successful occurrence sequence of the Petri net. In this paper, we investigate the structural subclass of place-labelled Petri net controlled grammar which focus on the state machine. We also establish the generative capacity of state machine of place-labelled Petri net controlled grammars
Couverture et Terminaison dans les réseaux de Petri Récursifs
International audienceIn the early two-thousands, Recursive Petri nets have been introduced in order to model distributed planning of multi-agent systems for which counters and recursivity were necessary. Although Recursive Petri nets strictly extend Petri nets and stack automata, most of the usual property problems are solvable but using non primitive recursive algorithms, even for coverability and termination. For almost all other extended Petri nets models containing a stack the complexity of coverability and termination are unknown or strictly larger than EXPSPACE. In contrast, we establish here that for Recursive Petri nets, the coverability and termination problems are EXPSPACE-complete as for Petri nets. From an expressiveness point of view, we show that coverability languages of Recursive Petri nets strictly include the union of coverability languages of Petri nets and context-free languages. Thus we get for free a more powerful model than Petri net
A performance analysis tool of discrete-events systems
The analysis of the logic correctness of the system and its performance evaluation are usually carried out using, respectively, the Petri nets formalism and the discrete-event simulation. Several tools exist for both. The Platform Independent Petri Net Editor (PIPE) is a free software tool developed in Java for the modelling, simulation and qualitative analysis of Petri nets. It has been designed with an open philosophy so that extensions can be easily incorporated. SIMAN is one of the first discrete-event simulation languages developed. It has extensively proven its power. This paper first presents a module for the PIPE software that allows the automatic generation of SIMAN code from a Petri net. Then, a tool is proposed to aid the performance analysis of manufacturing systems from its SIMAN model. These tools are designed as a support for students in the understanding of the simulation methodology
Capacity Bounded Grammars and Petri Nets
A capacity bounded grammar is a grammar whose derivations are restricted by
assigning a bound to the number of every nonterminal symbol in the sentential
forms. In the paper the generative power and closure properties of capacity
bounded grammars and their Petri net controlled counterparts are investigated
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Petri net equivalence
Determining whether two Petri nets are equivalent is an interesting problem from both practical and theoretical standpoints. Although it is undecidable in the general case, for many interesting nets the equivalence problem is solvable. This paper explores, mostly from a theoretical point of view, some of the issues of Petri net equivalence, including both reachability sets and languages. Some new definitions of reachability set equivalence are described which allow the markings of some places to be treated identically or ignored, analogous to the Petri net languages in which multiple transitions may be labeled with the same symbol or with the empty string. The complexity of some decidable Petri net equivalence problems is analyzed
Adjunct hexagonal array token Petri nets and hexagonal picture languages
Adjunct Hexagonal Array Token Petri Net Structures (AHPN) are re-
cently introduced hexagonal picture generating devices which extended the Hexag- onal Array Token Petri Net Structures . In this paper we consider AHPN model along with a control feature called inhibitor arcs and compare it with some ex- pressive hexagonal picture generating and recognizing models with respect to the
generating power
Algorithmic Verification of Asynchronous Programs
Asynchronous programming is a ubiquitous systems programming idiom to manage
concurrent interactions with the environment. In this style, instead of waiting
for time-consuming operations to complete, the programmer makes a non-blocking
call to the operation and posts a callback task to a task buffer that is
executed later when the time-consuming operation completes. A co-operative
scheduler mediates the interaction by picking and executing callback tasks from
the task buffer to completion (and these callbacks can post further callbacks
to be executed later). Writing correct asynchronous programs is hard because
the use of callbacks, while efficient, obscures program control flow.
We provide a formal model underlying asynchronous programs and study
verification problems for this model. We show that the safety verification
problem for finite-data asynchronous programs is expspace-complete. We show
that liveness verification for finite-data asynchronous programs is decidable
and polynomial-time equivalent to Petri Net reachability. Decidability is not
obvious, since even if the data is finite-state, asynchronous programs
constitute infinite-state transition systems: both the program stack and the
task buffer of pending asynchronous calls can be potentially unbounded.
Our main technical construction is a polynomial-time semantics-preserving
reduction from asynchronous programs to Petri Nets and conversely. The
reduction allows the use of algorithmic techniques on Petri Nets to the
verification of asynchronous programs.
We also study several extensions to the basic models of asynchronous programs
that are inspired by additional capabilities provided by implementations of
asynchronous libraries, and classify the decidability and undecidability of
verification questions on these extensions.Comment: 46 pages, 9 figure
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