212 research outputs found
Independence Analysis of Firing and Rule-based Net Transformations in Reconfigurable Object Nets
The main idea behind Reconfigurable Object Nets (RONs) is to support the visual specification of controlled rule-based net transformations of place/transition nets (P/T nets). RONs are high-level nets with two types of tokens: object nets (place/transition nets) and net transformation rules (a dedicated type of graph transformation rules). Firing of high-level transitions may involve firing of object net transitions, transporting object net tokens through the high-level net, and applying net transformation rules to object nets, e.g. to model net reconfigurations. A visual editor and simulator for RONs has been developed as a plug-in for ECLIPSE using the ECLIPSE Modeling Framework (EMF) and Graphical Editor Framework (GEF) plug-ins. The problem in this context is to analyze under which conditions net transformations and token firing can be executed in arbitrary order. This problem has been solved formally in a previous paper. In this contribution we present an extension of our RON tool which implements the analysis of conflicts between parallel enabled transitions, between parallel applicable net transformation rules (Church-Rosser property), and between transition firing and net transformation steps. The conflict analysis is applied to a RON simulating a distributed producer-consumer system
Subtyping for Hierarchical, Reconfigurable Petri Nets
Hierarchical Petri nets allow a more abstract view and reconfigurable Petri
nets model dynamic structural adaptation. In this contribution we present the
combination of reconfigurable Petri nets and hierarchical Petri nets yielding
hierarchical structure for reconfigurable Petri nets. Hierarchies are
established by substituting transitions by subnets. These subnets are
themselves reconfigurable, so they are supplied with their own set of rules.
Moreover, global rules that can be applied in all of the net, are provided
Reconfigurable Decorated PT Nets with Inhibitor Arcs and Transition Priorities
In this paper we deal with additional control structures for decorated PT
Nets. The main contribution are inhibitor arcs and priorities. The first ensure
that a marking can inhibit the firing of a transition. Inhibitor arcs force
that the transition may only fire when the place is empty. an order of
transitions restrict the firing, so that an transition may fire only if it has
the highest priority of all enabled transitions. This concept is shown to be
compatible with reconfigurable Petri nets
ReConNet: A Tool for Modeling and Simulating with Reconfigurable Place/Transition Nets
In this contribution we present a tool for modeling and simulation with reconfigurable Petri nets. Taking the idea of algebraic graph transformations to marked Petri nets we obtain Petri nets whose net structure can be changed dynamically. The rule-based change of the net structure enables the adequate modeling of complex, dynamic structures as for example of the scenarios of the Living Place Hamburg. The tool \reconnet \ uses decorated place/transition nets that are extended by various annotations. Especially, they have transition labels that may change when the transition fires. The transformation approach is based on the well-known algebraic transformation approach, but here we use a variant, namely the cospan approach, that inverts the relation between left- and right-hand sides and interface in the rules
Formal Modeling of Communication Platforms using Reconfigurable Algebraic High-Level Nets
Communication nowadays is based on communication platforms like Skype, Facebook, or SecondLife. The formal modeling and analysis of communication platforms poses considerable challenges, namely highly dynamic structures and complex behavior. Since most of the well-known formal modeling approaches are adequate only for specific aspects of communication platforms, in this paper we introduce the approach of reconfigurable algebraic high-level nets with individual tokens and show in our case study Skype that this approach is adequate for modeling the main aspects and features of communication platforms
RONs Revisited: General Approach to Model Reconfigurable Object Nets based on Algebraic High-Level Nets
Reconfigurable Object Nets (RONs) have been implemented in our
group to support the visual specification of controlled rule-based transformations
of marked place/transition (P/T) nets. RONs are high-level nets (system nets) with
two types of tokens: object nets (P/T nets) and net transformation rules. System net
transitions can be of different types to fire object net transitions, move object nets
through the system net, or to apply a net transformation rule to an object net. The
disadvantage of the RON approach and tool is the limitation of object nets to P/T
nets and the limitation of the underlying semantics of RONs due to the fixed types
for system net transitions. Often, a more general approach is preferred where the
type of object nets and the behavior of reconfigurations may be defined in a more
flexible way. In this paper, we propose to use Algebraic High-Level nets with individual
tokens (AHLI nets) as system nets. In this more general approach, tokens
may be any type of Petri nets, defined by the corresponding algebraic signature and
algebra. To support this general approach, a development environment for AHLI
nets is currently implemented which allows the user to edit and simulate AHLI nets.
We present the formalization of RONs as special AHLI nets and describe the current
state of the AHLI net tool environment
Formalization of Petri Nets with Individual Tokens as Basis for DPO Net Transformations
Reconfigurable place/transition systems are Petri nets with initial markings
and a set of rules which allow the modification of the net structure during runtime.
They have been successfully used in different areas like mobile ad-hoc networks.
In most of these applications the modification of net markings during runtime
is an important issue. This requires the analysis of the interaction between firing and
rule-based modification. For place/transition systems this analysis has been started
explicitly without using the general theory of M-adhesive transformation systems,
because firing cannot be expressed by rule-based transformations for P/T systems in
this framework. This problem is solved in this paper using the new approach of P/T
nets with individual tokens. In our main results we show that on one hand this new
approach allows to express firing by transformation via suitable transition rules. On
the other hand transformations of P/T nets with individual tokens can be shown to
be an instance ofM-adhesive transformation systems, such that several well-known
results, like the local Church-Rosser theorem, can be applied. This avoids a separate
conflict analysis of token firing and transformations. Moreover, we compare
the behavior of P/T nets with individual tokens with that of classical P/T nets. Our
new approach is also motivated and demonstrated by a network scenario modeling
a distributed communication system
Transfer of Local Confluence and Termination between Petri Net and Graph Transformation Systems Based on M-Functors
Recently, a formal relationship between Petri net and graph transformation systems has been established using the new framework of M-functors F : (C1;M1) -> (C2;M2) between M-adhesive categories. This new approach allows to translate transformations in (C1;M1) into corresponding transformations in (C2;M2) and, vice versa, to create transformations in (C1;M1) from those in (C2;M2). This is helpful because our tool for reconfigurable Petri nets, the RONtool, performs the analysis of Petri net transformations by analyzing corresponding graph transformations using the AGG-tool. Up to now, this correspondence has been implemented as a converter on an informal level. The formal correspondence results given by our framework make the RON-tool more reliable.In this paper, we extend this framework to the transfer of local confluence, termination and functional behavior. In particular, we are able to create these properties for transformations in (C1;M1) from corresponding properties of transformations in (C2;M2), where (C1;M1) are Petri nets with individual tokens and (C2;M2) typed attributed graphs. This allows us to apply the well-known critical pair analysis for typed attributed graph transformations supported by the AGG-tool in order to analyze these properties for Petri net transformations
Towards Model Checking Reconfigurable Petri Nets using Maude
This paper introduces an approach to model checking of reconfigurable Petri nets. The main task is to flatten the two levels of dynamic behavior that reconfigurable nets provide, the firing of transitions on the one hand and the transformation of the nets on the other hand. We show how to translate a reconfigurable net into Maude modules. Maude's LTL model-checker is then used to verify properties of these modules
- …