INCOMPLETE INPUT INFERENCE ON FUZZY PRODUCTION SYSTEMS SUPPORTED BY PETRI NETS

2000 ◽  
Vol 09 (04) ◽  
pp. 537-549
Author(s):  
SHYUE-LIANG WANG ◽  
TZUNG-PEI HONG

This paper proposes a new reasoning technique on fuzzy production systems while given input knowledge is incomplete. Based on the fuzzy Petri net formalism, the proposed algorithm can infer all possible conclusions and their corresponding missing inputs. The most possible conclusion can also be determined based on the criteria of the minimum number of missing inputs as well as the degree of truth of the conclusion. In addition, finiteness and computational complexity of the algorithm is investigated. As real decisions are typically made under incomplete input knowledge, this reasoning technique provides more realistic applications for fuzzy production systems.

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 489
Author(s):  
Oz Yakrangi ◽  
Roque J. Saltarén Pazmiño ◽  
Juan S. Cely ◽  
Alejandro Rodríguez ◽  
Cecilia E. García Cena ◽  
...  

The aim of this article is to present the fuzzy Petri net algorithm and its implementation on the Guide d’etude des modes de marche et d’arrêt (GEMMA) guide paradigm. Additionally, this article presents a brief description of the GEMMA guide paradigm, the fuzzy logic approach, the Petri nets theory, and fuzzy Petri nets. Each algorithm is intended for a specific set of transitions, depending on their essential conditions. All these algorithms generate intelligent and safe control of the GEMMA guide paradigm in order to have the best control system for the machine. Moreover, the algorithms are able to make the best decision automatically depending on the machine’s situation and condition, something that allows the machine to be placed in the appropriate mode for each situation. The results show that the different fuzzy Petri net algorithms were working properly for the GEMMA guide paradigm and provided a proper solution for the automation of production systems.


Author(s):  
Goharik Petrosyan ◽  
Armen Gaboutchian ◽  
Vladimir Knyaz

Petri nets are a mathematical apparatus for modelling dynamic discrete systems. Their feature is the ability to display parallelism, asynchrony and hierarchy. First was described by Karl Petri in 1962 [1,2,8]. The Petri net is a bipartite oriented graph consisting of two types of vertices - positions and transitions connected by arcs between each other; vertices of the same type cannot be directly connected. Positions can be placed by tags (markers) that can move around the network. [2] Petri Nets (PN) used for modelling real systems is sometimes referred to as Condition/Events nets. Places identify the conditions of the parts of the system (working, idling, queuing, and failing), and transitions describe the passage from one state to another (end of a task, failure, repair...). An event occurs (a transition fire) when all the conditions are satisfied (input places are marked) and give concession to the event. The occurrence of the event entirely or partially modifies the status of the conditions (marking). The number of tokens in a place can be used to identify the number of resources lying in the condition denoted by that place [1,2,8]. Coloured Petri nets (CPN) is a graphical oriented language for design, specification, simulation and verification of systems [3-6,9,15]. It is in particular well-suited for systems that consist of several processes which communicate and synchronize. Typical examples of application areas are communication protocols, distributed systems, automated production systems, workflow analysis and VLSI chips. In the Classical Petri Net, tokens do not differ; we can say that they are colourless. Unlike standard Petri nets in Colored Petri Net of a position can contain tokens of arbitrary complexity, such as lists, etc., that enables modelling to be more reliable. The article is devoted to the study of the possibilities of modelling Colored Petri nets. The article discusses the interrelation of languages of the Colored Petri nets and traditional formal languages. The Venn diagram, which the author has modified, shows the relationship between the languages of the Colored Petri nets and some traditional languages. The language class of the Colored Petri nets includes a whole class of Context-free languages and some other classes. The paper shows modelling the task synchronization Patil using Colored Petri net, which can't be modeled using well- known operations P and V or by classical Petri network, since the operations P and V and classical Petri networks have limited mathematical properties which do not allow to model the mechanisms in which the process should be synchronized with the optimal allocation of resources.


Author(s):  
A.N. Sochnev

The paper describes the approach to solving the problem of optimal planning of the production process. A discrete production system represented by the operations of machining, welding and painting was chosen as the object of research. The study states the problem of optimization of assembly production, which contains a typical criterion of optimality. A mechanism for meeting the criterion using a simulation model based on a Petri net is determined. The rules for developing feedback on the state of the network model and a method for controlling the simulation of the Petri net based on the analysis of its states are given. A binary function is used to analyze the states of the model. The developed approach to process optimization develops the theory of Petri nets, makes it more suitable for modeling complex systems with a branched structure and a large number of interconnections, which is a typical situation for production systems. The most universal approaches of control theory, e.g. feedback principle, are used, which implies a significant degree of universality and replicability of the approach. On the basis of the developed theoretical provisions, a test example is presented that characterizes the effect of their application. The presence of assembly production at most mechanical-engineering enterprises determines the high practical significance of the developed approach


2018 ◽  
Vol 226 ◽  
pp. 04001 ◽  
Author(s):  
Marina A. Ganzhur ◽  
Aleksei P. Ganzhur ◽  
Olga V. Smirnova

This work is devoted to solving the problem of modeling critical systems based on the use of modified Petri nets. The dual (binary) Petri net one of the modifications, which allows us to view inversing events at the same time, solving the problem with the possibility of deadlocks. Construction of schemes using fuzzy logic makes it possible to calculate the values of linguistic variables obtained knowledge. Petri dual network allows you to organize the exclusion of negative events by introducing additional links. In accordance with the rules, it is possible to construct a dual fuzzy Petri net, which involves the use of maximum and minimum transitions or appropriate logical calculations of conjunctions and disjunctions. Transition from classical Petri nets to dual fuzzy nets, realizes fuzzy knowledge of logical deriving that gives the chance in construction of expert systems with fuzzy logic solving a problem of data analysis.


Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 595 ◽  
Author(s):  
Muhammad Bashir ◽  
Liang Hong

Decentralized supervisory structure has drawn much attention in recent years to address the computational complexity in designing supervisory structures for large Petri net model. Many studies are reported in the paradigm of automata while few can be found in the Petri net paradigm. The decentralized supervisory structure can address the computational complexity, but it adds the structural complexity of supervisory structure. This paper proposed a new method of designing a global controller for decentralized systems of a large Petri net model for flexible manufacturing systems. The proposed method can both reduce the computational complexity by decomposition of large Petri net models into several subnets and structural complexity by designing a global supervisory structure that can greatly reduce the cost at the implementation stage. Two efficient algorithms are developed in the proposed method. Algorithm 1 is used to compute decentralized working zones from the given Petri net model for flexible manufacturing systems. Algorithm 2 is used to compute the global controller that enforces the liveness to the decentralized working zones. The ring assembling method is used to reconnect and controlled the working zones via a global controller. The proposed method can be applied to large Petri nets size and, in general, it has less computational and structural complexity. Experimental examples are presented to explore the applicability of the proposed method.


2020 ◽  
Vol 42 (12) ◽  
pp. 2206-2220
Author(s):  
Muhammad Bashir

The decentralized supervisory structure has drawn much attention in recent years. Many studies are reported in the paradigm of automata while few can be found in the Petri net model. This paper proposes a new method for decentralized supervisory control using the Petri net paradigm. Two efficient Algorithms are developed in the proposed method. Algorithm 1 is used to compute decentralized working zones from the given LS3PR Petri net model for flexible manufacturing systems. Algorithm 2 is used to compute the decentralized controllers that enforced liveness to the decentralized working zones. The sequential assembling is used to reconnect and controlled the working zones via decentralized controllers. The decentralized controller is added to the decentralized working zones that have common elements, that is, common transitions. The proposed method has the following advantages: (i) it can be applied to a complex Petri net model for flexible manufacturing systems, (ii) the proposed methods has less computational complexity when compared with the previous methods, (iii) the proposed method can obtain a minimal number of decentralized controllers that enforce liveness of the uncontrolled Petri net model. Experimental examples are presented to explore the applicability of the proposed methods.


Author(s):  
Gajendra Pratap Singh ◽  
Sujit Kumar Singh ◽  
Madhuri Jha

Boolean Petri net (BPN) and Crisp Boolean Petri net (CBPN) is a well-studied graph model since 2010 which has several applications in mathematical modeling of complex or tricky networks. Modeling any network with Petri net which can generate binary numbers as marking vectors in its reachability tree is still has much uses. In CBPN with a minimum number of transition and minimum number of steps of reachability tree, minimal execution time to run the machine has not been noted till date, thus it’s necessary to sort out this problem. Possibly it may occur due to some forbidden structure which hinders any 1-safe Petri net to be a CBPN. In this paper, we present some forbidden digraphs whose presence interrupts the generation of binary n-vectors exactly once. Any 1-safe Petri net is not a CBPN if it contains any of the subnet induced to the four forbidden structures discussed in this paper.


Author(s):  
Xiaozhong Li ◽  
Yong Li ◽  
Ying Liu ◽  
Long Wang

With the advances in technique for high throughput data gathering such as microarrays, DNA sequencing machines and continuous development of human genome project, the traditional physical and chemical methods have been more difficult to meet the requests of time consuming and results accuracy. Exploring and understanding the causal relationship of complex gene regulatory networks and transforming the massive data of large-scale biological research to useful biological knowledge are the present challenge. As a result, there are two typical applications both the confidence value prediction of DNA sequence and influence degree prediction of gene expression which have become the hot issues in our daily life. In this paper, two extended fuzzy Petri nets approaches are proposed, based on the existing fuzzy Petri net model, to model and analyze for the hot issues respectively. One is the fuzzy colored Petri net, which combines fuzzy Petri net with colored Petri net to model fuzzy rule-based reasoning and determine confidence values for bases called in DNA sequence. The other is extended fuzzy Petri net, which integrates reverse reasoning into fuzzy Petri net and is proposed to model gene regulatory network. It can predict the change in expression level of target based on the input expression level of activator/repressor. Compared with the method of fuzzy Petri net, the two extended fuzzy Petri nets models perform more accurately in the following typical experiment reasoning outcomes and show that the proposed methods are feasible and available.


1983 ◽  
Vol 6 (3-4) ◽  
pp. 333-374
Author(s):  
H.J.M. Goeman ◽  
L.P.J. Groenewegen ◽  
H.C.M. Kleijn ◽  
G. Rozenberg

This paper continues the investigation froll1 [Goeman et al.] concerning the use of sets of places of a Petri net as additional (to input places) constraints for granting concession. Now interpretations of more general constraints are considered and expressed as Boolean expressions. This gives rise to various classes of constrained Petri nets. These are compared in the language theoretical framework introduced in [Goeman et al.]. An upperbound for the language defining power is found in the class of context-free programmed languages.


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