scholarly journals Free-choice Nets with Home Clusters are Lucent

2021 ◽  
Vol 181 (4) ◽  
pp. 273-302
Author(s):  
Wil M.P. van der Aalst
Keyword(s):  
Petri Net ◽  
Free Choice ◽  
Process Models ◽  
Model Systems ◽  
Analysis Techniques ◽  
End Point ◽  
Challenging Question ◽  
Regeneration Point

A marked Petri net is lucent if there are no two different reachable markings enabling the same set of transitions, i.e., states are fully characterized by the transitions they enable. Characterizing the class of systems that are lucent is a foundational and also challenging question. However, little research has been done on the topic. In this paper, it is shown that all free-choice nets having a home cluster are lucent. These nets have a so-called home marking such that it is always possible to reach this marking again. Such a home marking can serve as a regeneration point or as an end-point. The result is highly relevant because in many applications, we want the system to be lucent and many “well-behaved” process models fall into the class identified in this paper. Unlike previous work, we do not require the marked Petri net to be live and stronglyconnected. Most of the analysis techniques for free-choice nets are tailored towards well-formed nets. The approach presented in this paper provides a novel perspective enabling new analysis techniques for free-choice nets that do not need to be well-formed. Therefore, we can also model systems and processes that are terminating and/or have an initialization phase.

scholarly journals A Logic Petri Net-Based Method for Repairing Process Models With Concurrent Blocks

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 8266-8282 ◽  
Author(s):  
Yuanxiu Teng ◽  
Yuyue Du ◽  
Liang Qi ◽  
Wenjing Luan
Keyword(s):  
Petri Net ◽  
Process Models

THE APPLICATION OF PETRI NETS TO WORKFLOW MANAGEMENT

1998 ◽  
Vol 08 (01) ◽  
pp. 21-66 ◽  
Author(s):  
W. M. P. VAN DER AALST
Keyword(s):  
Petri Nets ◽  
Petri Net ◽  
Business Processes ◽  
State Of The Art ◽  
Workflow Management ◽  
Explicit Representation ◽  
The Other ◽  
Application Domain ◽  
Analysis Techniques ◽  
The One

Workflow management promises a new solution to an age-old problem: controlling, monitoring, optimizing and supporting business processes. What is new about workflow management is the explicit representation of the business process logic which allows for computerized support. This paper discusses the use of Petri nets in the context of workflow management. Petri nets are an established tool for modeling and analyzing processes. On the one hand, Petri nets can be used as a design language for the specification of complex workflows. On the other hand, Petri net theory provides for powerful analysis techniques which can be used to verify the correctness of workflow procedures. This paper introduces workflow management as an application domain for Petri nets, presents state-of-the-art results with respect to the verification of workflows, and highlights some Petri-net-based workflow tools.

scholarly journals Heat transfer simulation of the cure of thermoplastic particle interleaf carbon fibre epoxy prepregs

2018 ◽  
Vol 53 (15) ◽  
pp. 2053-2064 ◽  
Author(s):  
Tassos Mesogitis ◽  
James Kratz ◽  
Alex A Skordos
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Sensitivity Study ◽  
Process Models ◽  
Analysis Techniques ◽  
New Class ◽  
Thermosetting Polymers ◽  
Heat Transfer Simulation ◽  
Thermal Analysis Techniques ◽  
Semi Empirical

Thermochemical properties are needed to develop process models and define suitable cure cycles to convert thermosetting polymers into rigid glassy materials. Uncertainty surrounding the suitability of thermal analysis techniques and semi-empirical models developed for conventional composite materials has been raised for the new class of particle interleaf materials. This paper describes kinetics, conductivity, heat capacity and glass transition temperature measurements of HexPly® M21 particle interleaf material. Thermal models describing conventional, non-particle epoxy systems were fit to the data and validated through a thick-section cure. Results from curing experiments agree with heat transfer simulation predictions, indicating that established thermal analysis techniques and models can describe polymerisation and evolving material properties during processing of a material representing the class of interleaf toughened systems. A sensitivity study showed time savings up to about 20%, and associated energy-efficiency-productivity benefits can be achieved by using cure simulation for particle interleaf materials.

Variability in Residual Myoglobin Content and Glutamic Oxaloacetic Transaminase (GOT) Activity in Cooked Bovine Semimembranosus Tissue as Related to Temperature of Cooking Media above End-point Temperature and Sample Size

1994 ◽  
Vol 57 (6) ◽  
pp. 502-504 ◽  
Author(s):  
SAMUEL D. SENTER ◽  
WILLIAM E. TOWNSEND ◽  
GAYLE K. SEARCY
Keyword(s):  
Sample Size ◽  
Model Systems ◽  
Actual Process ◽  
Probability Level ◽  
Glutamic Oxaloacetic Transaminase ◽  
Point Temperature ◽  
End Point ◽  
Thermally Processed ◽  
System Data ◽  
End Point Temperature

The variables, sample size and temperature of cooking media, were tested to determine their influence on myoglobin content and glutamic oxaloacetic transaminase (GOT) activities in bovine semimembranosus tissue thermally processed in a model heat treatment system. Data were obtained from 2.9 and 5.5 × 8.0 cm samples that were thermally processed to end-point temperatures (EPTs) of 62.8, 71.1 and 79.4°C in a water bath that exceeded EPTs by 2 and 20°C. Myoglobin denaturation differed (P < 0.05) by EPTs within samples, by sample size at the specified EPTs and by temperature of the heating media used to attain the EPTs within sample sizes. Similar variations at this probability level were observed in the analyses for residual GOT activities of the samples. Data indicate the inadequacies of analysis of these parameters in model systems that do not duplicate the actual process being evaluated.

Modeling Collaborative Engineering Design Process Using Petri-Net

2000 ◽  
Author(s):  
Li Zhao ◽  
Yan Jin
Keyword(s):  
Engineering Design ◽  
Design Process ◽  
Petri Net ◽  
Collaborative Design ◽  
Process Model ◽  
New Technologies ◽  
Process Models ◽  
Collaborative Engineering ◽  
Routine Design ◽  
High Level

Abstract Collaborative engineering involves multiple engineers and managers working together to develop engineering products. As the engineering problems become more and more complicated, new technologies are required to achieve better effectiveness and efficiency. While process models management and technologies have been developed to support engineering design, most of them apply only to routine design tasks and do not explicitly deal with the change of processes during execution. Our research proposes a process-driven framework to support collaborative engineering. The framework is composed of a process model that captures both high level and low level activity dependencies, an agent network that monitors process execution and facilitates coordination among engineers, and a Petri-net based modeling tool to represent and analyze process features and predict the performance of engineering processes. In this paper, we first describe a simple collaborative design problem and our proposed ActivePROCESS collaborative engineering framework. After that we present our Petri-net based analytical model of collaborative design process and discuss the model along with a case example.

Characterizing Liveness Monotonicity for Weighted Petri Nets in Terms of Siphon-Based Properties

2003 ◽  
Vol 14 (04) ◽  
pp. 641-658 ◽  
Author(s):  
Li Jiao ◽  
To-Yat Cheung
Keyword(s):  
Petri Nets ◽  
Petri Net ◽  
Free Choice ◽  
Sufficient Condition

A Petri net (N, M0) is monotonically live (m-live) if it remains live when the values of its initial marking M0 are increased. N is structurally m-live if there exists an initial marking M0 such that (N, M0) is m-live. Three new siphon-based characterizations for these properties are obtained: (1) For a weighted net N, the ST-property (i.e., every siphon contains a trap) is a necessary but not sufficient condition for N to be structurally m-live. (2) For a weighted net N, a necessary but not sufficient condition for (N, M0) to be m-live is that every siphon of N contains an M0-controlled trap (i.e., for every reachable marking M, the trap contains a place whose token value is not smaller than the least weight of its outgoing arcs). (3) A homogeneous asymmetric choice net (N, M0) is m-live if and only if every minimal siphon of N contains an M0-controlled trap. Characterization (3) is a generalization of Commoner's Theorem from ordinary liveness for ordinary free choice nets to m-liveness for homogeneous asymmetric choice nets.

scholarly journals Lower and upper bounds of shortest paths in reachability graphs

2004 ◽  
Vol 2004 (57) ◽  
pp. 3023-3036 ◽  
Author(s):  
P. K. Mishra
Keyword(s):  
Petri Nets ◽  
Shortest Path ◽  
Petri Net ◽  
Free Choice ◽  
Shortest Paths ◽  
Upper Bounds ◽  
Lower And Upper Bounds ◽  
Marked Graphs ◽  
Marked Graph

We prove the following property for safe marked graphs, safe conflict-free Petri nets, and live and safe extended free-choice Petri nets. We prove the following three results. If the Petri net is a marked graph, then the length of the shortest path is at most(|T|−1)⋅|T|/2. If the Petri net is conflict free, then the length of the shortest path is at most(|T|+1)⋅|T|/2. If the petrinet is live and extended free choice, then the length of the shortest path is at most|T|⋅|T+1|⋅|T+2|/6, whereTis the set of transitions of the net.

On a Decidable Class of Partially Controlled Petri Nets With Liveness Enforcing Supervisory Policies

2013 ◽  
Vol 43 (5) ◽  
pp. 1256-1261 ◽  
Keyword(s):  
Petri Nets ◽  
Petri Net ◽  
Free Choice ◽  
Closed Set ◽  
Construction Procedure ◽  
Transition Set

We identify a class of partially controlled Petri net (PN) structures, which is denoted by G, that strictly includes the class of partially controlled free-choice (FC) PN structures. We show that there is a supervisory policy that enforces liveness in an arbitrary instance N(m0), where N ∈ G, if and only if there is a similar policy for an FCPN that results when the construction procedure enunciated in this paper is executed with N and its controllable transition set as input. Since the existence of a supervisory policy in an arbitrary partially controlled FCPN is decidable, it follows that the existence of similar policies for any N(m0), where N ∈ G, is also decidable. Furthermore, when it exists, the minimally restrictive supervisory policy that enforces in a member of G is characterized by a right-closed set of markings.

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